Net-Zero and Positive Energy Communities: Best Practice Guidance Based on the ZERO-PLUS Project Experience 1032211857, 9781032211855

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Net-Zero and Positive Energy Communities

This book presents a methodology for the design, construction, monitoring, optimization, and post-occupancy evaluation of net-zero and positive-energy communities based on the experiences gained in the EU Horizon 2020 ZEROPLUS project. It describes the steps, tools, and methods developed during the project, providing practical information for the energy and construction sector that will be of interest to students, engineers, architects, developers, and professionals working around high-performance architecture and sustainable communities. Through the ZERO-PLUS project, a consortium of 32 partners from eight countries, including academic institutions, technology providers, architects, and construction companies, designed four communities covering completely different geo-climatic regions, construction practices, and cultural backgrounds in Cyprus, Italy, France, and the UK. The communities were designed, optimized, constructed, monitored, handed over to tenants, post-occupancy evaluated, and troubleshooted through a system of continuous collaboration and data acquisition. This book presents these case studies and shows how the project targets of reducing electricity consumption below 20 kWh/m2/y, increasing electricity production from Renewable Energy Systems to over 50 kWh/m2/y, and at cheaper costs when compared to current zero-energy buildings were reached and surpassed. These cases demonstrate that a holistic and interactive approach to design and construction can bring communities to a high standard of sustainability. The key features of the book include: • Practical guidance drawn from the interdisciplinary, international, and remote cooperation between experts from academia and industry across the construction sector. • A survey of the state-of-the-art on net-zero and positive-energy communities, including the experience and the lessons learned from previous projects and from the ZERO-PLUS project. • Descriptions of novel emerging renewable energy technologies, integrated into real case study communities to achieve the energy generation target of the communities. • A comprehensive set of approaches, tools, guidelines, best practices, challenges, and lessons learned from the five-year ZERO-PLUS project and the completion

of four residential case studies to inform the reader of how to achieve affordable net-zero energy communities. • Four typologies of residential communities located in different climatic conditions are presented, touching on the critical aspects of the design, construction, monitoring, and occupancy phase. • A discussion of future trends for developing communities that are more livable, accessible, and sustainable and which can comply with new energy policies in a way that is affordable for the owners and residents. Shabtai Isaac is Senior Lecturer in Project Management at Ben Gurion University of the Negev, Israel. Isaac Meir is Architect, Town Planner, Archaeologist, and Professor at Ben Gurion University of the Negev, Israel. Gloria Pignatta is Scientia Lecturer and City Futures Research Centre (CFRC) Fellow (2021–2024) in the School of Built Environment (BE), Faculty of Arts, Design, and Architecture (ADA), University of New South Wales, Australia.

Net-Zero and Positive Energy Communities Best Practice Guidance Based on the ZERO-PLUS Project Experience

Edited by Shabtai Isaac, Isaac Meir, and Gloria Pignatta

Cover images: Shabtai Isaac, Isaac Meir, and Gloria Pignatta First published 2024 by Routledge 4 Park Square, Milton Park, Abingdon, Oxon OX14 4RN and by Routledge 605 Third Avenue, New York, NY 10158 Routledge is an imprint of the Taylor & Francis Group, an informa business © 2024 selection and editorial matter, Shabtai Isaac, Isaac Meir, and Gloria Pignatta; individual chapters, the contributors The right of Shabtai Isaac, Isaac Meir, and Gloria Pignatta to be identified as the authors of the editorial material, and of the authors for their individual chapters, has been asserted in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library ISBN: 978-1-032-21185-5 (hbk) ISBN: 978-1-032-20846-6 (pbk) ISBN: 978-1-003-26717-1 (ebk) DOI: 10.1201/9781003267171 Typeset in Times New Roman by Apex CoVantage, LLC

Contents

Foreword

vii

SHABTAI ISAAC, ISAAC MEIR, AND GLORIA PIGNATTA

  1 Introduction to net-zero and positive-energy communities

1

KHAN RAHMAT ULLAH AND MATTHEOS SANTAMOURIS

  2 Background: the current energy community implementation state in the EU

19

ANNA LAURA PISELLO, CRISTINA PISELLI, AND BENEDETTA PIOPPI

  3 Methodology: the ZERO-PLUS approach

33

MORNA ISAAC AND SHABTAI ISAAC

  4 Part 1: UK case study

47

RAJAT GUPTA, MATT GREGG, AND OWEN DAGGETT

 

Part 2: Energy modeling of positive-energy dwellings

64

RAJAT GUPTA AND MATT GREGG

  5 Part 1: Italian case study

72

GLORIA PIGNATTA

 

Part 2: Community-level strategies for microclimate mitigation and energy efficiency improvement

89

CRISTINA PISELLI, SILVIA CAVAGNOLI, ANNA LAURA PISELLO, CLAUDIA FABIANI, AND FRANCO COTANA

  6 Part 1: Cypriot case study SALVATORE CARLUCCI, IOANNA KYPRIANOU, AND PANAYIOTIS PAPADOPOULOS

102

vi  Contents  

Part 2: Production and installation planning

119

WEN PAN AND SHABTAI ISAAC

  7 Part 1: French case study

130

SHABTAI ISAAC

 

Part 2: Project and design management – best practices and tools

135

SHABTAI ISAAC

  8 Part 1: Concentrating solar energy – the FAE system

144

FABIO MARIA MONTAGNINO

 

Part 2: Bot-based building design

151

BROOKE SPREEN AND SVEN KOEHLER

 

Part 3: Solar air-conditioning – the Freescoo system

160

PIETRO FINOCCHIARO

  9 Monitoring and evaluation of the performance of positive-energy communities

167

DIONYSIA KOLOKOTSA, ANGELIKI MAVRIGIANNAKI, AND KONSTANTINOS GOMPAKIS

10 Post-occupancy evaluation: the missing link

187

ISAAC MEIR



Conclusions, or a more critical rethinking of the project

204

ISAAC MEIR, SHABTAI ISAAC, AND GLORIA PIGNATTA

Index

207

Foreword

Climate is changing, with the increased frequency of extreme weather events, and the environment is facing depletion of its resources and ongoing harm. A long and animated argument on the anthropogenic contribution in such processes seems to have finally been settled, with the vast majority of the scientific community agreeing that we, humans, play a major – if not the major – role. Our reliance on energy and excessive consumption, the belief in continuous and endless growth, and the misconception (the illusion) that the environment can withstand it all have brought us to a critical state and very sad and dire straits. Within this context, buildings are a significant contributor and one of the major environmental degradation drivers. Buildings account for about 40% of the energy consumed in OECD (Organization for Economic Co-operation and Development) countries, including the operational energy (OE) for heating, cooling, ventilation, lighting, and operation of all building-related systems (e.g., elevators, escalators, pumps, fans, electric appliances). However, we keep forgetting that for buildings to be built, natural resources have to be mined and processed, building materials and elements have to be produced and transported, buildings have to be erected, and then, at the end of their life, demolished. Adding the energy needed for all this, the embodied energy (EE), easily brings the overall building budget in the energy consumed to some 50% of the overall energy use. Thus, we may say with a great degree of certainty and accuracy that buildings are responsible for at least half of our impact on the environment. What can be done about this, then? The concept of nearly zero-energy buildings (nZEBs) has been out there for several years, and several successful projects have been developed. Many countries have established protocols, created standards, and made laws and regulations to promote the adoption of nZEBs as the common paradigm and even reach the goal of true zero-energy buildings (ZEBs), moving from the “nearly zero-energy” level to an actual “zero-energy” level. This, though, seems not to be enough. Can buildings go beyond being just energy conservers and become energy surplus producers, generating more energy than they consume? This may be necessary, as mere energy conservation seems to be insufficient. Here comes in the current ZERO-PLUS energy project, whose aim was to create an all-inclusive package for designing and building energy-efficient buildings that

viii  Foreword go beyond the concept of nZEBs. The package includes design features that conserve both energy and resources (i.e., in terms of OE and EE) as well as integrates renewable energy systems based on renewable energy sources (RES) in buildings for electricity production. These could be easily modeled, but the real challenge is to actually build them as such. So the ZERO-PLUS project team, made up of 32 institutions and companies from eight countries, took upon itself to also build four demonstration case study settlements in four geo-climatically and socio-economically different locations, in Cyprus (CY), France (FR), Italy (IT), and the UK (UK). Taking the process and its targets one more step forward, the ZERO-PLUS team proposed to optimize the four case studies through energy and microclimate simulations and monitor their performance post-construction and pre-occupancy. This is to allow for any necessary adjustments and adaptations to be made. Finally, the project team proposed to conduct a post-occupancy evaluation (POE) to assess whether the building user/tenant is able to take full advantage of the energyefficient systems and RES incorporated into the design. The goal was to promote comfort, well-being, energy conservation, and potentially a sustainable development alternative through the building–user nexus. As more specific targets, the project consortium aimed at achieving building energy consumption of less than 20 kWh/m2/annum and energy production from RES of more than 50 kWh/m2/annum at the settlement level, at a cost of at least 16% cheaper than existing ZEBs. Furthermore, a carbon emission reduction target was established for each case study (i.e., CY, ≥34 kgCO2/m2/annum; FR, ≥4.6 kgCO2/m2/ annum; IT, ≥ 23 kgCO2/m2/annum; and UK, ≥ 18 kgCO2/m2/annum). The consortium brought together experts from various fields, including building design and construction, HVAC (heating, ventilation, and air-conditioning), and RES systems design and production, automation and telecommunications, as well as monitoring and POE, to reach these ambitious goals. Local regulators ensured compliance with national standards, and strict privacy watchdogs closely monitored every step of the process to guarantee full compliance with regulations protecting personal data. Despite facing typical and unexpected challenges, including construction projects contingencies and COVID-19-related shutdowns and restrictions, the consortium successfully moved from ZEBs to zero-plus-energy communities and exceeded its goals. The ZERO-PLUS project is not just another research project but a step toward a more sustainable future and the only reasonable way forward. We have demonstrated that it is possible and feasible to create net-zero and positive-energy communities if all related institutions, service and product providers, and stakeholders put their combined efforts into it. This book provides a comprehensive description and critical analysis of the ZERO-PLUS project and its modules, from beginning to end, from inception to use, discussing what has been done, where we went wrong, how we navigated straits, where we could have done better, but first and foremost, what a more appropriate design construction and commissioning process should look like if we are to reach a more sustainable development of communities. Not least, this book shows

Foreword ix what a whole, complete design and construction process should look like, including a circular process of studying, assessing, analyzing, and evaluating time and again the design and its details, the building systems and their usability, the building–user nexus, and their productive interaction. Without such a complete and whole process, well-being-promoting, energy-positive, healthy buildings cannot be achieved. Following is a brief overview of the structure of the book. The first section of the book, which contains three chapters, provides a broad introduction to the topic of net-zero and positive-energy communities and to the proposed methodology for realizing such communities. Chapter 1 introduces net-zero and positive-energy communities by reviewing existing precedents and highlighting existing problems and challenges. Chapter 2 defines and analyzes in detail energy communities according to the European regulatory and policy framework. Chapter 3 introduces the ZERO-PLUS approach for the design and construction of new residential netzero energy communities. The second section of the book, containing four chapters, shares the experience gained from the design and construction of four demonstration projects according to the approach and guidelines developed within ZERO-PLUS. Each chapter on a specific case study also contains a second part that focuses on a particular aspect of the project closely related to this case study. Chapter 4 describes the UK case study (Part 1) and presents the modeling, simulation, and optimization methods used from the design through to evaluation of zero-energy dwellings (Part 2). Chapter 5 describes the Italian case study (Part 1) and presents community-level strategies for microclimate mitigation and energy efficiency improvement (Part 2). Chapter 6 describes the Cypriot case study (Part 1) and presents a collaborative way of planning and managing the design, production, and on-site assembly processes for the energy-related technologies in NZE communities (Part 2). Chapter 7 describes the French case study (Part 1) and presents a collaborative project management approach that facilitates the creation of NZE communities and the tools and methods that were developed to support the approach. The third and final section of the book presents solutions that were developed within the ZERO-PLUS project, including technologies, tools, and methods. Chapter 8 presents some of the innovative energy technologies that were developed and implemented in the project: concentrating solar energy (Part 1), rooftop energy generation technologies (Part 2), and solar air-conditioning (Part 3). Chapter 9 presents the Monitoring and Evaluation Framework of the net-zero and positiveenergy communities. Chapter 10 presents a post-occupancy evaluation platform for the in-depth study and analysis of projects upon occupation. The ZERO-PLUS project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 678407. We thank Mattheos Santamouris for putting together the project team and managing its first steps. We thank Margarita-Niki Assimakopoulos for successfully carrying on the coordination of the project. Finally, we thank all the partners for collegiality, creativity, hard work, and bringing the project to a successful conclusion.

1

Introduction to net-zero and positive-energy communities Khan Rahmat Ullah and Mattheos Santamouris

1 Introduction The adverse environmental impacts and limited quantities of fossil fuels are not the only causes to explore energy alternatives. The rising energy consumption rate along with the energy poverty in the building sector are responsible for health problems and inadequate quality of life for low-income households (Pignatta et al., 2017). The fast advancement of built environment sectors around the globe is responsible for the use of the largest portion of global energy (Kumar & Cao, 2021). The major three sectors of energy consumption are industry, transportation, and buildings – residential, commercial, and others – where the building sector consumes around 40% of the world’s total energy that is responsible for 30% of global greenhouse gases (GHG) emissions (Kumar & Cao, 2021). To generate this huge amount of energy, the world massively relies on fossil fuels, where oil is still a dominant resource. About 90% of global energy is produced from conventional fossil fuels, while renewable resources are contributing 10% only (Elavarasan, 2019). The large amount of energy demand in the building sector is not only increasing global energy scarcity but also impacting climate change significantly (Roaf et al., 2015). Therefore, focusing on the climate targets, lessening the energy consumption and carbon emissions is essential, especially in the building sector. For this reason, many countries have embraced energy and carbon targets. For example, buildings are recognized by the vision of the Swiss 2000-Watt Society as a potential contributor toward improving energy efficiency and lowering GHG emissions (Stulz et al., 2011). These challenges have been driving toward the net-zero energy (NZE) concept in the building sector for the last few decades (Santamouris, 2016). The concept of net-zero energy building (NZEB) refers to those buildings having efficient and balanced architectural design and energy systems supplied by active and passive renewable technologies (Torcellini et al., 2006). It also balances energy generation and consumption, including the minimization of energy demand and energy costs, along with net-zero GHGs emission (Wells et al., 2018). Though the concept of NZEB in the built environment sector has been attracting researchers for the last couple of decades, the lack of global and extensive frameworks to define the NZEB and its requirements, especially the performance levels and the energy usage from the renewable energy resources, is still notable DOI: 10.1201/9781003267171-1

2  Khan Rahmat Ullah and Mattheos Santamouris (D’Agostino, 2015). This uncertainty has effects on building design, considering all the associated factors, such as energy generation and consumption, cost, thermal comfort, environmental impact, indoor air quality, etc. (Athienitis & O’Brien, 2015). This wide range of interpretations, along with the technological challenges regarding the operation and maintenance of technical tools, creates a barrier toward achieving the NZE purposes at the building levels that leads to an additional strategy, for example, at the community scale. 1.1  Definition of net-zero and positive-energy settlements

Energy performance and efficiency, power capacity, system reliability, and economy are the key factors in the consideration of the NZE concept, from the building to community levels (Goldthau, 2014). While NZEB is applied to focus on the NZE concept for the individual building, the net-zero energy settlement (NZES) consists of a community having several buildings that follow the trend of the NZE concept throughout the year. The term NZE refers to the energy demand of a community, which is equal to the on-site energy generated within the community throughout the year. According to the US Department of Energy, “a net zero energy community is an energy-efficient community where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy” (He et al., 2016). According to Carlisle et al. (2009), the net-zero energy settlement (NZES) is to be considered in the following four perspectives: 1. The central energy system should consist of renewable energy sources and will accommodate the energy for the whole community. 2. The percentage of energy loss should be kept in mind to deliver the energy. 3. The financial aspects of the community should be considered. 4. The environmental impacts, including GHG emissions, are to be considered. While the NZES concept concerns equalizing energy demand and energy supply throughout the year, the positive-energy community yields more renewable energy than its demand, along with providing appropriate comfort levels, reducing carbon emissions, and increasing the overall performance of energy systems. More specifically, it has been believed as a step forward toward NZES (Kumar & Cao, 2021). 1.2  T  ransition of NZE concept from an individual building to community level

While the importance of future energy systems in the building sector is obvious, it is almost impossible to analyze and consolidate the energy dynamics of buildings perfectly if we consider individual and isolated single-building energy systems (Kumar & Cao, 2021). Several studies point out the benefits of expanding the boundaries of energy analysis from building scale to a collective approach on the community level, even sometimes widening to district scale (Staller et al., 2016).

Introduction to net-zero and positive-energy communities 3 Integrated energy planning has become widespread and inevitable for the urban environment. Various synergies, as well as amenities, can be identified during the optimization of building energy performance while we consider it on a larger scale. The community-scale initiative can provide enhanced energy security and energy independence (Karunathilake et al., 2019). There are several advantages of NZES over NZEB, as follows: • It offers the sharing of needs, costs, and resources among the buildings within the community that is beneficial and cost-effective (Isaac et al., 2020). • The mismatch between energy generation and demand generally occurs at the building levels, where the aggregated building approach within the community can ensure more balanced management of it (Dai et al., 2015). Oversizing of the whole system can be avoided by assessing the total energy demand and sharing (Amaral et al., 2018). • The centralized energy system enables the management of the various energy resources locally, which offers the flexibility to balance supply and demand with the help of an energy storage system that can also allow new consumers/end users, like electric mobility. Since the process of generation and distribution of energy runs in parallel, therefore, the losses (due to distribution of energy and the surplus energy) can be minimized significantly in NZES compared to the NZEB (Kurnitski et al., 2013). • While the retrofitting of the energy technologies within the existing building stock creates challenges, the centralized energy system at the community level allows more flexibility to serve the net-zero energy purposes (Marique & Reiter, 2014). • The net-zero energy target is more feasible for low-rise residential buildings than high-rise buildings, where energy generated at the community level can efficiently handle such types of big demands (Fong & Lee, 2012). • A microgrid at the community level can supply excess energy to the national energy grid, allowing additional earnings for the system. Also, when the loads cannot be handled by renewables, the community can meet the additional energy demand from the local grid. This approach, which is not possible at the building level, does not fully serve the net-zero energy purpose but nearly net-zero energy purpose only (Marique & Reiter, 2014). 2 Typologies of NZES The ways of serving NZE purpose on the community level consist of various elements and approaches. It is the approach not only to generate the required energy from renewables but also to reduce the energy demands by improving the microclimate and incorporating the passive elements within the buildings of the settlement. The methods to achieve the NZE purpose on the community level refer to: • The mitigation of the outdoor heat sources for the improvement of microclimate (Santamouris et al., 2019; Santamouris et al., 2017).

4  Khan Rahmat Ullah and Mattheos Santamouris

Figure 1.1  The various components of an NZES. Source: Ullah et al. (2021).

• The adaptation of the buildings to improve indoor thermal comfort (TaveresCachat et al., 2019). • The installation of renewables to generate the required energy for the community (Taveres-Cachat et al., 2019). The microclimate mitigation strategy enables mitigating the outdoor heat sources, thus allowing to reduce the cooling energy consumption within the community. The widely used technologies for this mitigation approach are urban greenery, the use of cool materials (Akbari et al., 2001; Pisello et al., 2015), water-based evaporative systems, etc. (Wu & Zhang, 2019). Besides, the adaptation of buildings refers to the sustainable design and techniques (e.g., incorporation of building envelope and insulation with state-of-the-art materials, improved ventilation, efficient lighting, thermal storage systems, building geometry, natural lighting, etc.) (Oh et al., 2017) that facilitate the improvement of the indoor environment of the buildings, including minimizing heat losses in winter and maximizing heat losses in summer, and renewable energy technologies play the key roles to generate the required electrical and thermal energy for the settlement (Taveres-Cachat et al., 2019). Besides, a smart monitoring and control system enhances the usage of onsite produced energy from renewable sources, lessens the energy curtailment, and prevents the oversizing for both the energy generation and energy storage tools and devices, which intends to reduce the investment and the operation and maintenance costs (Sokolnikova et al., 2020). 3 Existing application and outcomes There are several research efforts done regarding NZE settlements around the globe. While most of the studies deal with software simulation, some real field

Introduction to net-zero and positive-energy communities 5 applications practically confirm the viability of the technologies employed for NZES. The current applications of these technologies, along with their outcomes, are described in the next three sub-sections. 3.1  T  he strategies for mitigation of outdoor heat sources used in net-zero energy settlements

The mitigation strategies are usually applied to the outdoor heat sources of the settlements to reduce the ambient temperature of the environment, which leads to lessening the energy demand within the community. For serving the NZE purpose, vegetation strategy is primarily considered to mitigate the outdoor heat sources. For example, in the practically implemented NZES, namely, “UC Davis West Village,” various native trees, shrubs, grasses, and other native plants were planted to reduce the temperature of the environment (Wheeler & Segar, 2013; Dakin & Hoeschele, 2010). However, the studies did not explicitly determine the outcome of these mitigation strategies. In another case study of the NZES in Rimini, Italy, landscaping vegetation was based on deciduous trees and hedges, which enabled to reduce the ambient temperature up to 2℃, which allowed to reduce the energy consumption by about 4–5% of annual energy demand (Castaldo et al., 2018; Piselli et al., 2020). For the case study of Pieria, Greece, various plants, including bougainvillea, shrubs, ground covers, vines, and turf, were considered for the vegetation. As a result, almost 76% of polluting emissions could be reduced (Ascione et al., 2017). Beside the vegetation, there are some other mitigation strategies followed to achieve the NZE goals at community level. Natural, cool gravels were considered for pavements for the settlement of Rimini, Italy. The study also recommended using highly reflective asphalt for the roads. These measures resisted the ambient heat to sink within the ground (Castaldo et al., 2018; Piselli et al., 2020). The highly reflective asphalt used on road albedo was also considered in the study of nearly zero-energy district in Rome, Italy. The result showed that 8% energy demand was reduced by adopting these mitigation strategies within the district (Boccalatte et al., 2020). 3.2  The adaptation of the buildings used for net-zero energy settlements

The adaptation of the building refers to the use of several measures, like highly reflective materials on external walls and roof, windows with advance materials and technologies, high-quality insulation and ventilation systems, etc. The building envelope is a crucial factor that controls the indoor conditions independent of transient open-air conditions of the buildings. It segregates the outdoor and indoor conditions of the buildings by incorporating some advanced materials and tools on the walls, rooftop, and fenestration of the buildings (Nalcaci & Nalcaci, 2020). For example, as one of the real-life applications of these measures, UC Davis West Village used batt and blown insulation for the wall and the roof, respectively, where a radiant barrier was used as roof sheathing. They also incorporated highly reflective

6  Khan Rahmat Ullah and Mattheos Santamouris glazing windows and NightBreeze fresh air mechanical ventilation system, which reduced the thermal energy demand to about 65%, 58%, and 50% for single-family houses, multi-family houses, and common areas, respectively (Wheeler & Segar, 2013; Dakin & Hoeschele, 2010). On the other hand, for the case study of Rimini, Italy, extruded polystyrene was used as insulation, where highly reflective tiles were considered for roof and external walls, and the windows were made of doubleglazing low-e materials with PVC frames along with a mechanical ventilation system. The result showed that up to 10% of the energy demand could be reduced for HVAC (Castaldo et al., 2018; Piselli et al., 2020). This study was further expanded by Cardinali et al. (2020), who showed that about 22% of energy could be saved, along with 5% of the CO2 emissions reduction on community scale. Ascione et al. (2017) designed the roofs and terrace to be covered with arbor or wattle, whereas the terrace would be paved with highly reflective materials. Indoor shedding would be provided by indoor blinds, lattices, and curtains, and the windows would be made from double clear glass, argon-filled cavity, and wooden frames. They suggested natural materials (stone, brick, and wood) and light colors to be used in the opaque envelope of the buildings. These measures reduced the heating and cooling energy demand by up to 70%. In the case study of Plus Energy Settlement in Freiburg, Germany, a decentralized mechanical ventilation system was implemented. Insulation was considered for external walls, roofs, and floors, where low-e triple-glazed windows were implemented within the buildings. However, the study did not summarize the effect of such adaptation strategies (Heinze & Voss, 2009). Another practically implemented sustainable urban district is Vauban, located in Freiburg, Germany (Coates, 2013). The buildings of this community consisted of high level of insulation in walls, triple-glazed windows with two heat-reflecting surfaces, mechanical ventilation, and some large linden trees planted beside the houses for summer shading. However, this study also did not mention the outcomes of adopting such adaptation strategies as well. Arena and Faakye (2015) considered cellulose as an insulating material for ceiling, roof, wall, and slab. The windows incorporated in the buildings were made of triple-plane, low-e chlorinated polyvinyl chloride (CPVC) materials, where energy recovery ventilation (ERV) type of ventilation was used. However, the insulation strategy was not well addressed, and the sizing and positioning of the windows were not adequate. For the case study of a mixed-use community in Calgary, Canada, buildings with 30–35% south-facing glazing were considered, where triple-glazed, low-e, argon-filled windows were used along with the insulation of the exterior wall and gable roof. The study included the interior blind shading and concrete slab for the floor, along with a ventilation system that allowed a higher rate of ventilation compared to the reference. However, the effects of using the adaptation measures were not summarized (Hachem-Vermette et al., 2016). Similar windows were also considered for the case study of the NZES in Granarolo dell’Emilia, Italy (Mavrigiannaki, Pignatta, et al., 2021). For the case study of Cairo, Egypt, external rendering was considered for the insulation of roof and wall alongside the green rooftop as the adaptation strategies of the buildings that reduced 18% of carbon emissions and 57.6% of annual energy

Introduction to net-zero and positive-energy communities 7 consumption. Nevertheless, the building envelope and the ventilation strategies were not addressed (Fouad et al., 2020). Synnefa et al. (2017) considered extruded polystyrene as insulating material of the building envelope. The same adaptation approach was followed by Sougkakis et al. (2020), who considered three levels of insulation for the roof, floor, and wall of the buildings, but effect on the building energy performance is missing. Extruded polystyrene was also used for external walls, along with the low-e, triple-glazing windows with unplasticized polyvinyl chloride (uPVC) frame, which reduced more than 30% of energy consumption for both dwellings in the case study of York, England (Gupta & Gregg, 2016, 2018). For the nearly zero-energy district in Rome, Italy, high thermal resistance and cladding were considered for the roof and walls, with double-glazing windows that reduced about 70% of the thermal energy demand (Boccalatte et al., 2020). 3.3  T  he renewable energy technologies and the energy management strategies used in net-zero energy settlements

The pace of the transition of energy from conventional fossil fuels to renewable energy resources has been increasing over the last couple of decades. The relative part of renewable energy is significantly growing in the global electricity demand, estimated at 29% in 2020, compared to 27% in 2019. Alongside governments, several regional communities and private sectors are also playing key roles to contribute their part to such renewable energy growth. Energy production and management are based on both centralized and decentralized systems throughout the community, depending on the availability of the resources and the suitability of the installation of energy production and management tools (Kumar & Cao, 2021). There are several renewable energy sources as well as technological tools employed to generate electrical and thermal energy along with the storage and control system to meet the energy demand and therefore achieve the NZE goals within the communities. Though solar energy is considered the most widely used resource, some other renewable energy sources have also been used over the last few decades to generate thermal and electrical energy for the NZES. For example, in the UC Davis West Village, a centralized solar PV system with the capacity of 4 MW was installed. Besides, a community waste-based biogas fuel cell plant was incorporated, where thermal energy of the community was provided by active solar water heating and heat pump. However, the community has not achieved the NZE goals yet, since the energy demand of the community is still higher than the on-site energy generation of the community. This happens due to the lower capacity of installed solar PV, where 5.4 MW was planned to be installed (Wheeler & Segar, 2013; Dakin & Hoeschele, 2010). At the NZE community of Rimini, Italy, rooftopinstalled PV and Windrail were considered to generate electrical power, and a highly efficient HVAC system was proposed. The proposed model yielded about 70% energy reduction per building compared to the reference scenario (Castaldo et al., 2018; Piselli et al., 2020). For the case study of the Mediterranean climate in Pieria, Greece, PV was used to generate the electrical energy, where hot water was produced by gas boilers. A hydronic air-conditioning system was proposed,

8  Khan Rahmat Ullah and Mattheos Santamouris where space cooling was provided by electric air-conditioning units. These measures reduced the energy demand by up to 90%. However, the strategies to control and balance the energy demand and supply were absent (Ascione et al., 2017). In the Plus Energy Settlement of Freiburg, Germany, a 400 kWp PV was installed on the building roofs along with a combined heat and power (CHP) plant to supply electrical and thermal energy to the community with a positive-energy balance and in an emission-free manner, but it had to depend on the local grid, for lack of an energy storage system (Heinze & Voss, 2009). The sustainable urban district of Vauban in Freiburg, Germany, has a similar problem, lacking an energy storage system, but generation was higher than the demand (Coates, 2013). The rooftop PV and solar hot water system along with a natural gas–powered CHP unit were integrated within the building, enabling a 79% reduction in primary energy along with 80% GHG emission reduction. The simulation on the Eco Village at Ithaca, New York, incorporated PV and solar thermal collectors along with heat pump and thermal storage system to serve the NZE needs of 40 residential buildings. The suggested solution package faced the oversizing problem of the energy tools, since the energy consumption data collected from two occupied homes was 56% lower than the MJ8 software calculation, while the Passive House Planning Package (PHPP) calculation provides a figure 34% higher than the recorded data (Arena & Faakye, 2015). The mixed-use community of Calgary, Canada, was designed to include building-integrated PV (BIPV) system, alongside a heat pump and a chiller, providing heating and cooling, respectively. The installation of PV on the roof failed to ensure the energy-plus status of the multi-storied buildings due to the comparatively restricted space on the roof for installing the PV according to the demand. As a result, the school and houses have a net positive impact on the environment, while other buildings could not achieve it (Hachem-Vermette et al., 2016). Wind turbines and PV were considered for the case study of NZES in Cairo, Egypt (Fouad et al., 2020), where energy consumption could be reduced by about 57.6% along with the reduction of 390 tons of CO2 per year. These renewables were further considered in the case study of the NZES in Granarolo dell’Emilia, Italy (Mavrigiannaki, Gobakis, et al., 2021), where Windrail and PV were considered to be installed on the settlement level along some BIPV. This settlement is an outcome of the ZERO-PLUS project of the EU Horizon 2020 program, where the on-site energy generation was about 60 kWh/m2/year against the net-regulated energy consumption of 1.6 kWh/m2/year, with a reduction of up to 33% of the cost. The NZES designed by Synnefa et al. (Synnefa et al., 2017) consisted of a compact linear Fresnel reflector, translucent BIPV glass component, compact solar thermal driven HVAC system, thermal storage system connected to the solar field and absorption chillers, Windrail module, and a microgrid to generate, control, and supply the energy. The study met its target of yearly renewable energy generation and net-regulated energy use but failed to address the optimization of the economic and technical perspective. The opposite phenomena were observed by the study conducted on the nearly zero and positive-energy settlement in Alexandroupolis, Greece (Sougkakis et al., 2020), where PV, geothermal heat pump, and battery made the settlement viable, considering the economy and technologies, but energy monitoring and control system are missing. Almost similar technologies

Introduction to net-zero and positive-energy communities 9 were considered for the nearly zero energy community in South Korea (Suh & Kim, 2019), where PV, solar thermal collector, and geothermal heat pump were considered, but without energy storage systems. The study observed four different cases of renewable energy resources, where the first two cases failed to reach the NZE goals. The study of the nearly zero energy district in Rome, Italy, consisted of BIPV installed on the roof and facades of the building, along with an electric heat pump, where the performance of the PV module decreased for a massive coverage of the facade and rooftop by the PV (Boccalatte et al., 2020). The net-zero multi-energy community in Siberia, Russia, was simulated by Sokolnikova et al. (2020), where PV, wind turbines, heat pump, energy control and management strategy, along with the battery and thermal storage system used, enabled achieving the NZE goals along with the reduction of CO2 emissions of about 3,000 tons within the community. Similar renewable energy technologies were considered in the positive-energy community of Finland (Rehman et al., 2019). Besides the PV and wind turbine, the study included a central solar district heating system consisting of a solar thermal collector, heat pumps, and a borehole thermal energy storage system. In addition, the study included electric vehicles to be fed from the on-site energy generated within the community. The result showed that the system reduced the electrical energy imported from the grid by up to 2 kWh/m2/year while an energy storage system was considered. Another suggestion has been brought by Garmsiri et al. (2016) regarding the integration of vehicles fed by on-site energy generated within the community. They examined the feasibility of an NZES by utilizing captured waste hydrogen from chlor-alkali plants, along with building-integrated PV/thermal system. The result showed that about 1,200 kg of hydrogen can be produced that would be processed via Honda FCX fuel cells to feed the 750 electric vehicles successfully. However, results showed that the NZE purpose would be served if the vehicles are considered as loads besides the building energy demand within the community. A combined PV/T system was considered for the case of York, England (Gupta & Gregg, 2016, 2018). Besides building-integrated PV and modular wind turbines considered for electrical energy generation, a gas boiler district heating system was incorporated on the settlement level. The study suggested that more than 30% of energy can be saved within the existing dwellings, and more than 35% of CO2 emissions could be reduced. However, though the settlements significantly improved the amount of on-site energy generation by renewables, the NZE goals are yet to be achieved. Jordan et al. (2016) considered solar PV and battery (as energy storage) only to serve the NZE purpose in Mayaguez, Puerto Rico. The study showed that energy balance was merely achievable on sunny days, whereas on cloudy days, the community required to consume energy from the local grid. The study was limited to be used for low-energy consumption community only. There are some studies that do not consider the electrical and thermal perspective simultaneously toward achieving NZE goals at the community level. For example, a central biogas plant and a gas turbine were used in the ADM1 model to be used for the NZES in Ontario, Canada (Shareefdeen et al., 2015). The design mainly focused on the thermal energy supply of the community, where about 23% CO2 emissions can be reduced, compared to the conventional natural

10  Khan Rahmat Ullah and Mattheos Santamouris gas production system. However, though the study included a gas turbine, it did not include any discussion on or specification of the turbine and its output power. Burch et al. (2012) considered a solar PV/T system and borehole field heat storage system for energy generation and storage devices, where he emphasized the performance of thermal energy supply liquid desiccants (LD) method that ensured significant reduction of piping diameter, therefore also reduction of the cost for heating and cooling purpose. However, the study discussed only the thermal perspective, but no design of electrical components was considered. The technologies employed for NZE purpose on the community level are listed in Table 1.1. Table 1.1 The technologies employed and their significance toward achieving NZE goals on the community level List of technologies

Outcomes

Mitigation

• Reduction of the ambient temperature, energy demand, and polluting emissions up to 2℃, 8%, and 76%, respectively.

Adaptation

Renewables

Energy management and control system

• Vegetation (trees, shrubs, grasses, plants, hedges, etc.) • Cool and reflective materials for roads and pavements (natural cool gravels, highly reflective asphalt, etc.) • Low-e multi-glazing windows • High-insulating and reflecting materials for wall, roof, and floor (e.g., extruded polystyrene, batt and blown insulation, highly reflective tiles, arbor or wattle, stone, brick and wood, etc.) • Efficient ventilation systems (mechanical ventilation, ERV ventilation, HVAC systems, etc.) • Shading (by trees, indoor blinds, lattices, curtains, etc.) • PV and solar thermal collector • WindRail and wind turbine • CHP system • Biogas plant, geothermal energy, and gas turbine • Community waste (hydrogen energy utilized by fuel cells) • Heat pump • Battery and thermal storage systems • Microgrid system • Energy control strategy

• Up to 70% of heating and cooling energy demand reduction. • Significant minimization of annual GHG emissions (up to 18%) and annual energy demand.

• Up to 80% of GHG emissions reduced thanks to renewable energy resources. • Energy cost can be reduced up to 33%. • Vehicles can feasibly be added to the NZE system. • Energy storage system enhances the energy performance of the system. • Microgrid controls the electrical energy generation and supply. • Home energy management system increases the selfconsumption of renewable energy sources.

Introduction to net-zero and positive-energy communities 11 4 Conclusion and scope of further studies Evidence reveals that most of the NZE settlements mainly involve on-site energy generation rather than the measures to reduce the energy consumption of the settlements. Also, the barriers toward achieving NZE goals consist of several factors (e.g., inadequate and inappropriate energy generation tools and energy storage system, lack of control system, microgrid, etc.). However, various adaptation techniques are capable to lessen significantly the building energy demand. Nonetheless, the adaptation tools are not thoroughly considered yet, and there are also some new technologies to be introduced for the adaptation of buildings. Moreover, mitigation strategies enable lowering the ambient temperature along with curbing GHG emissions to the environment, as well as minimizing the energy demand of the community. Though this approach is widely used in several individual cases, it is time to incorporate it extensively to mitigate the outdoor heat sources of the NZES. The challenges of existing NZE communities and corresponding recommendations are made in the following sub-section. 4.1  P  resent challenges and scope of further studies for net-zero energy communities

Though NZESs have been considered over the last few decades, there are still several challenges and, therefore, scopes of further study and research for achieving NZE goals at the community level. From the preceding discussion, we can summarize the findings and the insights as follows: • Mitigation strategies and adaptation of the buildings are two key elements to achieve NZE goals on the community level. Those have been substantiated by previous studies to minimize the ambient temperature (up to 3℃), leading to a reduction of the energy demand of the community (Boccalatte et al., 2020). But these measures have not been thoroughly considered by NZE settlements which have been realized. Therefore, comprehensive assimilation of the tools and measures for mitigation and adaptation of the buildings is yet to be achieved. • Vegetation, natural cool gravels (Castaldo et al., 2018; Piselli et al., 2020), and highly reflective asphalt (Boccalatte et al., 2020) are considered as mitigation strategies which are limited in the extent to which they can be practically implemented in NZE communities. Besides, the assessment of the effects of incorporation of mitigation strategies are, sometimes, missing in the actual field application (Wheeler & Segar, 2013; Dakin & Hoeschele, 2010). • The measures and tools used for adaptation techniques in the buildings of some settlements were not widely considered with state-of-the-art tools and technologies, though it would enhance the energy performance of the building (Arena & Faakye, 2015; Fouad et al., 2020). Therefore, ample and high-performance tools and measures are yet to be incorporated. • Most of the settlements have considered solar energy as a renewable energy source, while wind energy was second, along with geothermal energy, biogas plant, etc., which are not enough in quantities.

12  Khan Rahmat Ullah and Mattheos Santamouris • For the enhancement of the self-consumption of energy (Sokolnikova et al., 2020) (Mavrigiannaki, Pignatta, et al., 2021) and the improvement of handling capacity of critical loads and balancing the good distribution of energy demand (Synnefa et al., 2017; Jordan et al., 2016), it is essential to incorporate energy control and management systems. But they are not extensively included in NZES yet, as few settlements considered them, and those are mostly limited to software simulations. • The utilization of community waste would become a good source of energy – for example, biogas fuel cell plant fed by agricultural and dining hall food waste (Wheeler & Segar, 2013; Dakin & Hoeschele, 2010) and the utilization of waste hydrogen from chlor-alkali plants (Garmsiri et al., 2016, etc.). Nevertheless, the use of community waste in NZE settlements is still not appropriately implemented or even considered. • Though the environmental impacts along with the energy demand and supply are discussed, a comprehensive cost analysis for the NZE settlements considering the per unit energy costs and payback period of the systems is yet to be conducted. • There are limited appropriate methodologies and tools that include all the parameters and factors (e.g., site coverage or shape factor, floor area, floor and ground space indexes, etc.) for researchers as well as practitioners. Even software tools sometimes neglect the geometric parameters and assume the default values during simulations that influence the energy performance of the renewable technologies within the community (Ullah et al., 2021). • The larger scale and area of the community bring more complexity in designing the system, guaranteeing functional stakeholders’ interactions (Mavrigiannaki, Pignatta, et al., 2021), and in assessing the performance of the system. Therefore, we can conclude that, considering on-site energy generation, there are already some successfully implemented NZES in the world, but there are still some scopes and areas (illustrated in Figure 1.2) to be addressed so as to improve the economic perspective, environmental friendliness, technical flexibility, and social viability of NZES. The major current gap resides in exploring stakeholders’ motivations as well as awareness of the NZE concept. Therefore, to establish NZES, further areas can be explored, as follows: 1. Mitigation strategies. At present, a limited number of case studies considered the mitigation strategies for outdoor heat sources to serve NZE goals within the community, where vegetation is mainly considered. However, along with vegetation, water bodies (Santamouris et al., 2017), and cool materials for roads and pavements (e.g., third-generation materials) (Santamouris et al., 2011), thermochromic coatings (Garshasbi & Santamouris, 2019), electrochromic glass, white marbles, super-cool materials (Santamouris & Yun, 2020), and photonic materials (Feng et al., 2021), etc.) could be adopted to improve the thermal comfort of the environment within the community. 2. Adaptation of the buildings. Till now, there has been an inadequate incorporation of the state-of-the-art passive elements within the buildings of the

Introduction to net-zero and positive-energy communities 13

Figure 1.2  Further measures and tools for future NZES. Source: Ullah et al. (2021).

community. Therefore, an extensive adaptation of the buildings with highperformance materials would be a promising option to reduce the energy demand and improve the indoor air quality as well as control the indoor temperature of the buildings. In this process, some new technologies (e.g., PCM in walls (Stritih et al., 2018) and cool roof materials (Green et al., 2020)) could be integrated in buildings. 3. Diversified use of renewables. Solar and wind energy are mainly considered renewable energy sources in most of the case studies. Hence, there are some other renewable energy resources and technologies (e.g., hydrogen energy (Ullah et al., 2015), thermoelectric generator, hydro energy, tidal energy, etc.) that would be good sources of energy to serve the net-zero purpose at the community level. 4. Energy management and control system design. There are very few efforts done to design and implement comprehensive control systems. Hence, implementing smart monitoring and control systems will enable to lessen the oversizing of the technical tools and the mismatch between the demand and generation of energy within the community. Besides, the formation of a microgrid connected to the conventional national grid and all the renewable energy tools would enable the distribution of the energy along with balancing the energy demand within the year, which is thoroughly not considered in NZE communities yet. 5. Usage of waste energy. Waste energy of the community can be harvested to meet partial energy demand (e.g., hydrogen energy by the fuel cell and industrial/

14  Khan Rahmat Ullah and Mattheos Santamouris domestic waste heat by thermoelectric generator), which is not widely devised yet for NZES. 6. Life cycle assessment. A comprehensive life cycle assessment, including the cost analysis and the payback period, along with the environmental impacts of the centralized system, is essential for the viability of the community, which is not often assessed in previous works. 7. Usage of updated software tools. Appropriate software selection brings the flexibility to select the required design parameters according to the weather condition and climatic zone, enabling to get the more accurate results to design NZES. 8. Awareness and motivation of the residents. The NZE concept is not wellknown to the community people. Therefore, social awareness regarding it and its benefits can be achieved via surveys and physical communication. References Akbari, H., Pomerantz, M., & Taha, H. (2001). Cool surfaces and shade trees to reduce energy use and improve air quality in urban areas. Solar Energy, 70(3), 295–310. https:// doi.org/10.1016/S0038-092X(00)00089-X Amaral, A. R., Rodrigues, E., Rodrigues Gaspar, A., & Gomes, Á. (2018). Review on performance aspects of nearly zero-energy districts. Sustainable Cities and Society, 43, 406– 420. https://doi.org/10.1016/J.SCS.2018.08.039 Arena, L., & Faakye, O. (2015). EcoVillage: A Net Zero Energy Ready Community. https:// doi.org/10.2172/1220427 Ascione, F., Bianco, N., De Masi, R. F., Dousi, M., Hionidis, S., Kaliakos, S., Mastrapostoli, E., Nomikos, M., Santamouris, M., Synnefa, A., Vanoli, G. P., & Vassilakopoulou, K. (2017). Design and performance analysis of a zero-energy settlement in Greece. International Journal of Low-Carbon Technologies, 12(2), 141–161. https://doi.org/10.1093/ IJLCT/CTW003 Athienitis, A., & O’Brien, W. (2015). Modeling, design, and optimization of net-zero energy buildings. Wiley Online Library, 1–374. https://doi.org/10.1002/9783433604625 Boccalatte, A., Fossa, M., & Ménézo, C. (2020). Best arrangement of BIPV surfaces for future NZEB districts while considering urban heat island effects and the reduction of reflected radiation from solar façades. Renewable Energy, 160, 686–697. https://doi. org/10.1016/J.RENENE.2020.07.057 Burch, J., Woods, J., Kozubal, E., & Boranian, A. (2012). Zero energy communities with central solar plants using liquid desiccants and local storage. Energy Procedia, 30, 55–64. Cardinali, M., Pisello, A. L., Piselli, C., Pigliautile, I., & Cotana, F. (2020). Microclimate mitigation for enhancing energy and environmental performance of near zero energy settlements in Italy. Sustainable Cities and Society, 53, 101964. Carlisle, N., Van Geet, O., & Pless, S. (2009). Definition of a ‘zero net energy’ community. National Renewable Energy Laboratory (NREL), Golden, CO (United States). Castaldo, V. L., Pisello, A. L., Piselli, C., Fabiani, C., Cotana, F., & Santamouris, M. (2018). How outdoor microclimate mitigation affects building thermal-energy performance: A new design-stage method for energy saving in residential near-zero energy settlements in Italy. Renewable Energy, 127, 920–935. https://doi.org/10.1016/J.RENENE.2018.04.090 Coates, G. J. (2013). The sustainable Urban district of Vauban in Freiburg, Germany. International Journal of Design and Nature and Ecodynamics, 8(4), 265–286. https://doi. org/10.2495/DNE-V8-N4-265-286

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16  Khan Rahmat Ullah and Mattheos Santamouris Heinze, M., & Voss, K. (2009). Goal: Zero energy building exemplary experience based on the solar estate Solarsiedlung Freiburg am Schlierberg, Germany. Journal of Green Building, 4(4), 93–100. https://doi.org/10.3992/JGB.4.4.93 Isaac, S., Shubin, S., & Rabinowitz, G. (2020). Cost-optimal net zero energy communities. Sustainability, 12(6), 2432. https://doi.org/10.3390/SU12062432 Jordan, I. L., O’Neill-Carrillo, E., & Lopez, N. (2016). Towards a zero net energy community microgrid. 2016 IEEE Conference on Technologies for Sustainability (SusTech), 63–67. https://doi.org/10.1109/SUSTECH.2016.7897144 Karunathilake, H., Hewage, K., Mérida, W., & Sadiq, R. (2019). Renewable energy selection for net-zero energy communities: Life cycle based decision making under uncertainty. Renewable Energy, 130, 558–573. https://doi.org/10.1016/J.RENENE.2018.06.086 Kumar, G. M. S., & Cao, S. (2021). State-of-the-art review of positive energy building and community systems. Energies, 14(16), 5046. https://doi.org/10.3390/EN14165046 Kurnitski, J., Alard, F., Braham, D., van Dijk, D., Feidmann, C., Fox, J., Graslund, J., Heiselberg, P., Hovorka, F., Kosonen, R., & Lebrun, J. (2013). REHVA nZEB Technical Definition and System Boundaries for Nearly Zero Energy Buildings: REHVA Report No. 4, 2013. Scientific Research Publishing. Retrieved March 20, 2023, from www.scirp.org/ (S(oyulxb452alnt1aej1nfow45))/reference/referencespapers.aspx?referenceid=1548723 Marique, A. F., & Reiter, S. (2014). A  simplified framework to assess the feasibility of zero-energy at the neighbourhood/community scale. Energy and Buildings, 82, 114–122. https://doi.org/10.1016/J.ENBUILD.2014.07.006 Mavrigiannaki, A., Gobakis, K., Kolokotsa, D., Kalaitzakis, K., Pisello, A. L., Piselli, C., Laskari, M., Saliari, M., Assimakopoulos, M.-N., Pignatta, G., Synnefa, A., & Santamouris, M. (2021). Zero energy concept at neighborhood level: A case study analysis. Solar Energy Advances, 1, 100002. https://doi.org/10.1016/J.SEJA.2021.100002 Mavrigiannaki, A., Pignatta, G., Assimakopoulos, M., Isaac, M., Gupta, R., Kolokotsa, D., Laskari, M., Saliari, M., Meir, I. A., & Isaac, S. (2021). Examining the benefits and barriers for the implementation of net zero energy settlements. Energy and Buildings, 230, 110564. https://doi.org/10.1016/j.enbuild.2020.110564 Nalcaci, G., & Nalcaci, G. (2020). Modeling and implementation of an adaptive facade design for energy efficiently buildings based biomimicry. 8th International Conference on Smart Grid, IcSmartGrid, 140–145. https://doi.org/10.1109/ ICSMARTGRID49881.2020.9144954 Oh, J., Hong, T., Kim, H., An, J., Jeong, K., & Koo, C. (2017). Advanced strategies for net-zero energy building: focused on the early phase and usage phase of a building’s life cycle. Sustainability, 9(12). https://doi.org/10.3390/SU9122272 Pignatta, G., Chatzinikola, C., Artopoulos, G., Papanicolas, C. N., Serghides, D. K., & Santamouris, M. (2017). Analysis of the indoor thermal quality in low income Cypriot households during winter. Energy and Buildings, 152. https://doi.org/10.1016/j. enbuild.2016.11.006 Piselli, C., Di Grazia, M., & Pisello, A. L. (2020). Combined effect of outdoor microclimate boundary conditions on air conditioning system’s efficiency and building energy demand in net zero energy settlements. Sustainability, 12(15). https://doi.org/10.3390/SU12156056 Pisello, A. L., Castaldo, V. L., Piselli, C., Pignatta, G., & Cotana, F. (2015). Combined thermal effect of cool roof and cool façade on a prototype building. Energy Procedia, 78. https://doi.org/10.1016/j.egypro.2015.11.205 Rehman, H. ur, Reda, F., Paiho, S., & Hasan, A. (2019). Towards positive energy communities at high latitudes. Energy Conversion and Management, 196, 175–195. https://doi. org/10.1016/J.ENCONMAN.2019.06.005

Introduction to net-zero and positive-energy communities 17 Roaf, S., Brotas, L., & Nicol, F. (2015). Counting the costs of comfort. Building Research & Information, 43(3), 269–273. https://doi.org/10.1080/09613218.2014.998948 Santamouris, M. (2016). Innovating to zero the building sector in Europe: Minimising the energy consumption, eradication of the energy poverty and mitigating the local climate change. Solar Energy, 128, 61–94. https://doi.org/10.1016/j.solener.2016.01.021 Santamouris, M., Ding, L., Fiorito, F., Oldfield, P., Osmond, P., Paolini, R., Prasad, D., & Synnefa, A. (2017). Passive and active cooling for the outdoor built environment – analysis and assessment of the cooling potential of mitigation technologies using performance data from 220 large scale projects. Solar Energy, 154, 14–33. https://doi.org/10.1016/J. SOLENER.2016.12.006 Santamouris, M., Ding, L., & Osmond, P. (2019). Urban Heat Island Mitigation in Decarbonising the Built Environment (pp. 337–355). Springer. https://doi.org/10.1007/ 978-981-13-7940-6_18 Santamouris, M., Synnefa, A., & Karlessi, T. (2011). Using advanced cool materials in the urban built environment to mitigate heat islands and improve thermal comfort conditions. Solar Energy, 85(12), 3085–3102. https://doi.org/10.1016/J.SOLENER.2010.12.023 Santamouris, M., & Yun, G. Y. (2020). Recent development and research priorities on cool and super cool materials to mitigate urban heat island. Renewable Energy, 161, 792–807. https://doi.org/10.1016/J.RENENE.2020.07.109 Shareefdeen, Z., Elkamel, A., Perera, L., Vaideswaran, K., & Jinxu Zhang, J. Z. (2015). Design and analysis of a biogas digester for a net-zero energy community in southwestern Ontario. 2015 International Conference on Industrial Engineering and Operations Management (IEOM). https://doi.org/10.1109/IEOM.2015.7093887 Sokolnikova, P., Lombardi, P., Arendarski, B., Suslov, K., Pantaleo, A. M., Kranhold, M., & Komarnicki, P. (2020). Net-zero multi-energy systems for Siberian rural communities: A methodology to size thermal and electric storage units. Renewable Energy, 155, 979– 989. https://doi.org/10.1016/J.RENENE.2020.03.011 Sougkakis, V., Lymperopoulos, K., Nikolopoulos, N., Margaritis, N., Giourka, P., & Angelakoglou, K. (2020). An investigation on the feasibility of near-zero and positive energy communities in the Greek context. Smart Cities, 3(2), 362–384. https://doi.org/10.3390/ SMARTCITIES3020019 Staller, H., Rainer, E., Heimrath, R., Halmdienst, C., Martín, C. V., & Grabner, M. (2016). +ERS – plus energy network Reininghaus Süd: A pilot project towards an energy selfsufficient urban district. Energy and Buildings, 115, 138–147. https://doi.org/10.1016/J. ENBUILD.2015.06.049 Stritih, U., Tyagi, V. V., Stropnik, R., Paksoy, H., Haghighat, F., & Joybari, M. M. (2018). Integration of passive PCM technologies for net-zero energy buildings. Sustainable Cities and Society, 41, 286–295. https://doi.org/10.1016/J.SCS.2018.04.036 Stulz, R., Tanner, S., & Sigg, R. (2011). Swiss 2000-watt society. In Energy, Sustainability and the Environment (pp. 477–496). Elsevier. https://doi.org/10.1016/B978-0-12385136-9.10016-6 Suh, H. S., & Kim, D. D. (2019). Energy performance assessment towards nearly zero energy community buildings in South Korea. Sustainable Cities and Society, 44, 488– 498. https://doi.org/10.1016/J.SCS.2018.10.036 Synnefa, A., Laskari, M., Gupta, R., Pisello, A. L., & Santamouris, M. (2017). Development of net zero energy settlements using advanced energy technologies. Procedia Engineering, 180, 1388–1401. https://doi.org/10.1016/J.PROENG.2017.04.302 Taveres-Cachat, E., Grynning, S., Thomsen, J., & Selkowitz, S. (2019). Responsive building envelope concepts in zero emission neighborhoods and smart cities – a roadmap to

18  Khan Rahmat Ullah and Mattheos Santamouris implementation. Building and Environment, 149, 446–457. https://doi.org/10.1016/J. BUILDENV.2018.12.045 Torcellini, P., Pless, S., Deru, M., & Crawley, D. (2006). Zero Energy Buildings: A Critical Look at the Definition; Preprint. www.osti.gov/bridge Ullah, K. R., Akikur, R. K., Ping, H. W., Saidur, R., Hajimolana, S. A., & Hussain, M. A. (2015). An experimental investigation on a single tubular SOFC for renewable energy based cogeneration system. Energy Conversion and Management, 94, 139–149. https:// doi.org/10.1016/J.ENCONMAN.2015.01.055 Ullah, K. R., Prodanovic, V., Pignatta, G., Deletic, A., & Santamouris, M. (2021). Technological advancements towards the net-zero energy communities: A review on 23 case studies around the globe. Solar Energy, 224, 1107–1126. https://doi.org/10.1016/J. SOLENER.2021.06.056 Wells, L., Rismanchi, B., & Aye, L. (2018). A review of net zero energy buildings with reflections on the Australian context. Energy and Buildings, 158, 616–628. https://doi. org/10.1016/J.ENBUILD.2017.10.055 Wheeler, S. M., & Segar, R. B. (2013). Zero net energy at a community scale: UC Davis West village. In F. P. Sioshansi (Ed.), Energy Efficiency: Towards the End of Demand Growth (1st ed., pp. 305–324). Elsevier. Wu, Z., & Zhang, Y. (2019). Water bodies’ cooling effects on urban land daytime surface temperature: Ecosystem service reducing heat island effect. Sustainability, 11(3), 787. https://doi.org/10.3390/SU11030787

2

Background: the current energy community implementation state in the EU Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi

1 Introduction The energy transition toward a decarbonized future offers the possibility of implementing innovative and effective new policies toward faster economic and social sustainable development (Amin, 2018). This path involves the digitalization of the energy sector, the reduction of renewable energy costs, and the development of new models of distributed energy generation. In particular, with the increasing decentralization of energy generation, individuals and companies are able to play a proactive role in the energy system, allowing the growth of new resource management schemes and, consequently, business models. In this context, a new archetype for the national and European energy system is arising: energy communities (ECs), where citizens produce, consume, manage, and share renewable energy. Energy communities have been introduced in the European regulatory framework by the “Clean Energy for all Europeans Package” (European Commission, 2020a), which includes the European directives governing renewable energy production and sharing that define the schemes of collective self-consumption and energy community. The term “energy community” refers to a legal entity constituted – in accordance with national law – openly and voluntarily. It is autonomous and controlled by shareholders or members located in proximity of the renewable energy production plant that belongs to and is developed by the same legal entity (Figure 2.1). The shareholders or members can be individuals, smalland medium-sized enterprises (SMEs), or local authorities, including municipalities, which constitute the EC in order to provide environmental, economic, and social benefits rather than financial profit. Practically, the energy community can be set up between users belonging to the same low-voltage network, namely, those users that refer to the same medium/low-voltage (MV/LV) substation. Therefore, it can combine various end uses characterized by different “energy use profiles,” which are usually out of phase in time (e.g., office buildings, small manufacturing companies, residential buildings, etc.), in order to benefit from the non-contemporaneity of energy needs. Collective self-consumption, instead, is a specific scheme that can be established only between users belonging to the same condominium who produce (store) and consume renewable energy (Frieden et al., 2019).

DOI: 10.1201/9781003267171-2

20  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi

Figure 2.1  Example of energy community scheme with different building uses.

In the international panorama, the discussion is led by the group headed by the IEA EBC Annex 83 “Positive Energy Districts” (Reda & Tuominen, 2020). Indeed, ECs can be assimilated to positive energy districts (PEDs), since PEDs’ base principle is to create an area within the built urban context where renewable energy is generated more than required in an agile and flexible way, namely, capable of responding to the variation of the dynamic energy market – not only producing more energy than required on an annual static basis. PEDs should be able to minimize the impact of fluctuations in demand and production, offering further possibilities of synchronization of loads and self-consumption, even through energy storage solutions and system flexibility optimization using advanced multidirectional flow control mechanisms. The final objective is always the same: to cope with the fact that in Europe buildings are responsible for approximately 40% of energy consumption and 36% of CO2 emissions (European Commission, 2020a). This condition requires a prompt action from various points of view, and energy communities seem an effective solution in terms of both urban carbon footprint reduction and resilience to fluctuating markets and “unpredictable” environmental phenomena, as well as safe renewable sources supply. From the economic point of view, ECs give rise to a double benefit. On the one hand, they provide greater energy self-sufficiency for the country that adopts them and, consequently, independence from foreign imports. On the other hand, thanks to the self-production and internal sharing of energy, community members save the charges on the bill and potentially recreate a sense of community among “peers” with also socio-demographic benefits. Indeed, the integration of energy communities into the energy system must be carried out efficiently from the economic perspective, by taking into account the real savings for the energy system as a whole, to ensure feasibility. Nevertheless, equally important is the potential social benefit that derives from these new forms of aggregation (Gjorgievski et al., 2021).

The current energy community implementation state in the EU 21 Energy communities take on a strong social value because they enhance human involvement and awareness on the control of energy process (consumption and production of energy), guarantee inclusiveness, and have impact in the long term, potentially triggering green individual behaviors and social practices. Consequently, through ECs the energy transition creates roles for new actors: innovation and social transformation through the involvement of citizens and the reduction of energy poverty. Indeed, the European energy market is experiencing not only the transformation from an energy system based on fossil and nuclear energy to a system based on renewable, efficient, and sustainable energy but also the transformation from a centralized market toward a granular, distributed, and resilient market, with prosumer citizens, that is, active citizens in the energy system (Amin, 2018). This chapter starts from the analysis of the regulatory framework of the European Union to understand the feasibility and the current state of implementation of energy communities in Europe. Thereafter, the lesson learned from the Horizon 2020 (H2020) ZERO-PLUS project (H2020 Project ZERO-PLUS, 2015) is discussed with specific reference to the experience in a laggard country in the implementation of energy communities, that is, Italy. Finally, the current progress in this path is presented by analyzing the following projects that are going beyond ZERO-PLUS. 2 European context 2.1  European regulatory framework

In the European regulatory framework, certain categories of community energy initiatives are recognized as energy communities. They were introduced, as aforementioned, with the “Clean Energy for all Europeans Package” (European Commission, 2020a) in 2019. The energy community is intended as a means for organizing collective energy actions based on models of governance and open and democratic participation in order to provide benefits for its members and for the local community (Roberts et al., 2019). In particular, two of the revised European directives define energy communities: the Directive 2018/2001/EU (revised Renewable Energy Directive – RED II) (Directive (EU) 2018/2001 of the European Parliament and of the Council on the Promotion of the Use of Energy from Renewable Sources, 2018), which promotes energy from renewable sources and renewable self-consumption, introduces “renewable energy communities” (REC), while the Directive 2019/944/EU (Internal Electricity Market Directive – EMD II) (Directive (EU) 2019/944 on Common Rules for the Internal Market for Electricity, 2019), on common rules for the internal electricity market, introduces “citizens’ energy communities” (CEC). In both cases, the regulatory framework describes energy communities as new types of non-commercial legal entities that provide for open and voluntary participation, without discrimination. They aggregate shareholders, who can be individuals, local entities, and small- and medium-sized enterprises, whose primary

22  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi economic activity cannot be the participation in the energy community. Although they engage in an economic activity, energy communities have the main objective to provide environmental, social, and economic benefits to the members of the community and the territory where they are located, rather than to provide financial profit (Rescoop, 2019). The main differences between CEC and REC are related to geographical and energy characteristics (Caramizaru & Uihlein, 2020): • RECs require that energy generation and self-consumption take place in close proximity, while CECs do not. • CECs operate specifically in the electricity sector and may also involve fossil fuel generation, while RECs – as the name implies – encompass all forms of renewable energy in the electricity and thermal energy sectors and aspire to be energy-autonomous. Therefore, the European Union recognizes and proposes a legislative framework favorable to the development of energy communities, which are expected to pave the way for a citizen-centric clean energy transition, while increasing public acceptance of renewable energy and attracting private investments in clean energy (European Commission, 2020b). For the first time, the collective participation of citizens in the energy system is significantly promoted (Figure 2.2). Accordingly, the implementation of the “Clean Energy Package” at a national level in each member state is essential for the profitable development of energy communities toward the energy transition, as well as adequate technical and operational support from local administrations (Ren et al., 2015). 2.2  Virtuous cases in Europe

Energy community projects exist in various forms across Europe. Since the 1980s, energy community initiatives have been developing, yet only recently, as previously mentioned, has the EU started developing a policy framework to define energy communities in legal terms and to foster their operation. Nowadays, over 1,900 projects exist across the EU, involving over 1,250,000 citizens (Energy Transition. The Global Energiewende, 2021). The most common are those involving renewable energy generation. Table 2.1 summarizes the indicative number of active energy communities led by citizen groups in selected European countries by 2020. This number is expected to continuously evolve. Indeed, the European Commission apprises that, in the transition to cleaner and more sustainable energy by 2030, energy communities may own up to 17% of wind power and 21% of solar power (European Commission, 2016). Although they aim at being autonomous, energy communities remain connected to the energy system – exceptions are granted for isolated areas, such as islands or remote areas. As regards the organizational models and legal forms, there is high heterogeneity. The most widespread typology is the energy cooperative. This model was established with the introduction of renewable energy support schemes (indeed, they are particularly popular in countries where the latter are relatively advanced) and mainly favors ECs

The current energy community implementation state in the EU 23

Figure 2.2  The energy system fostered today vs. the energy system of yesterday.

members, according to the main purpose of energy communities (Caramizaru & Uihlein, 2020). In terms of diffusion, the largest number of energy communities firstly developed in European countries with a tradition of community-owned and social enterprises, namely, the Netherlands, Denmark, and Germany, in ascending order (H2020 Project COMETS, 2019) (Table 2.1). For example, the energy cooperative Bioenergiedorf (which means “bioenergy village”), born in 2005 in Jühnde, Germany (de Waal & Stremke, 2014), was the first village to be self-sufficient in terms of thermal and electrical energy, capable of producing renewable energy from biomass with the participation of consumers. Another example is the Schoonschip residential district in Amsterdam, the Netherlands (Stichting, 2020), where every home is equipped with an intelligent heat pump energy system and renewable energy production systems – photovoltaic panels and solar collectors – supported by electric and thermal storage systems. Each house is connected to the internal microgrid of the community, which has a single point of connection and exchange with the central grid. The community microgrid is controlled via an intelligent

24  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi Table 2.1  Active energy communities in selected European countries Country

Number of energy community initiatives

Germany Denmark Netherlands United Kingdom Sweden France Belgium Poland Spain Italy

1,750 700 500 431 200 70 34 34 33 12

Source: Caramizaru and Uihlein (2020).

platform capable of managing and optimizing local renewable energy exchange and administrative activities. Luče Community is a village in a remote part of Slovenia (H2020 Project COMPILE, 2018), which represents a case of rural network of building with different end uses served by multiple renewable energy production systems, such as photovoltaic panels, wind turbines, biomass-based heat generators, and charging stations for electric vehicles. In this context, the presence of a local community grid allows for optimizing the balance between supply and demand of clean energy thanks to the flexibility associated with the various production systems and end users, that is, prosumers, with diversified and asynchronous energy needs. In the town of Monachil, Spain (Ecosystemic Transition Unit (ETU), 2020), the local residents are brought together to be part of the energy transition through the production of their own renewable energy and the establishment of a REC, while sharing surplus with other communities. A key challenge to set up a successful energy community stressed in this project is the need to engage and raise awareness about energy self-consumption on its inhabitants. To this aim, energysharing groups and educational activities are carried out by the municipality to communicate the benefits of the energy communities. 3 Beyond ZERO-PLUS 3.1  Lesson learned

The H2020 project ZERO-PLUS (H2020 Project ZERO-PLUS, 2015) provided an approach for the design and construction of net-zero energy settlements (NZES) in different European countries. Therefore, the proposed approach was implemented and tested in selected case studies, including a small-scale settlement in Italy (Granarolo dell’Emilia) (Cardinali et al., 2020; Castaldo et al., 2018; Mavrigiannaki et al., 2021). These NZES were designed with a configuration typical of energy communities, with expected renewable energy production and management systems shared among the buildings in the settlement. However, in the implementation phase, different barriers were faced to the effective application of this approach.

The current energy community implementation state in the EU 25 Among the main ones, there was a big policy barrier on a legal basis related to the implementation of community contracts in Italy. In detail, at that time, different consumers could not share energy contract. This non-negligible barrier prevented the implementation of shared energy systems among the buildings of the Italian case study settlement and, therefore, the proper implementation of the ZERO-PLUS approach. Accordingly, this issue highlighted the need of shared and acknowledged policies on energy communities at national and – most of all – EU level. Moreover, dedicated regulatory models to be applied to these new subjects should be agreed. On the other hand, a key variable enabling the feasibility of energy communities is users’ understanding and acceptance of this novel approach to energy use. Therefore, strategies aimed at mobilizing interest and trust among citizens must be defined to foster a human-based energy transition. Results from the project showed that this is a challenge to be faced (Piselli et al., 2021). In this view, the right mix of incentives for all stakeholders (not only bottom-up but also top-down) should be provided. Finally, technical barriers emerged within the framework of the project. First, the need to develop and select easy and acknowledged technologies. Indeed, innovative renewable energy systems require environmental and/or other permissions to be effectively installed in the settlement outdoors as shared systems. Furthermore, the phases of operation and maintenance of the shared systems involve additional issues related to privacy and intrusion that should be taken into account when designing energy communities. 3.2  National regulatory framework in Italy

As regards policies, a key achievement related to the ZERO-PLUS project was the development of a national regulatory framework for energy communities in Italy. The policy barriers faced during the project, indeed, drove the local researchers to push to a legislative adaptation of the Italian policies to those of early adopter countries of this solution in Europe. The Italian “Milleproroghe” Decree, that is, Legislative Decree of December 30, 2019, n. 162 (Decreto-Legge 30 dicembre 2019, n. 162 “Disposizioni urgenti in materia di proroga di termini legislativi, di organizzazione delle pubbliche amministrazioni, nonché di innovazione tecnologica” (in Italian), 2019) – which was pushed also by the Italian researchers who were involved in the ZERO-PLUS project – officially published on February 29, 2020, and came into force on March 1, 2020, laid the foundations for the establishment of renewable energy communities in Italy. Until then, the Italian legislation allowed producing and self-consuming energy, but only in terms of 1:1, namely, with the producer as the only consumer (Quaranta, 2020). For instance, if the owner of an apartment in a condominium had installed a photovoltaic system on the roof, they would have been the only one to be able to use the energy produced by this system, which, therefore, could not have served, when exceeding, the other utilities nearby or even in the same condominium. Similarly, the energy surplus of a photovoltaic system installed on the

26  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi roof of a company could have been fed into the network, but not used, for example, to cover all or part of the energy needs of a neighboring company (Candelise & Ruggieri, 2020). Therefore, despite numerous mechanisms aimed at encouraging electric renewable energy sources such as photovoltaic, geothermal, wind power, etc., which have led to an increase in renewable energy production up to covering approximately 14% of national production over the years 2000–2012 (GSE, 2019), this constraint has slowed the development of self-consumption potential. This limit was overcome thanks to the “Milleproroghe” Decree and the conversion law of February 28, 2020, n.8 (Legge 28 febbraio 2020, n. 8 “Conversione in legge, con modificazioni, del decreto-legge 30 dicembre 2019, n. 162” (in Italian), 2020). Indeed, this regulation has started implementing the provisions of the European Directive 2018/2001/EU (Directive (EU) 2018/2001 of the European Parliament and of the Council on the Promotion of the Use of Energy from Renewable Sources, 2018) by legally recognizing renewable energy sharing, according to the two mechanisms aforementioned: collective self-consumption and energy communities. Thereafter, the most recent legislative decree of November 8, 2021, n. 199 (Decreto Legislativo 19 novembre 2021, n. 199 “Attuazione della direttiva (UE) 2018/2001 del Parlamento europeo e del Consiglio, dell’11 dicembre 2018, sulla promozione dell’uso dell’energia da fonti rinnovabili” (in Italian), 2021), which should be followed by the implementing decrees and regulations within six months from its publication, definitively transposes the Directive 2018/2001/EU. The regulatory evolution in Italy is summarized in Figure 2.3. More in detail, Article 42-bis of “Milleproroghe” Decree, coordinated with Law 8/2020, outlines the path toward distributed generation from renewable sources, that is, methods and conditions for activating collective self-consumption and/or creating energy communities, in terms of plants sizing, producer–consumer legal model, provisions regarding the treatment of the energy produced, and tariff mechanisms. On the one hand, it specifies that the self-consumers of renewable energy who act collectively (in collective self-consumption schemes) must be in the same building or condominium. Moreover, subjects other than households can join only if the aforementioned activities are not their main commercial or professional activity. On the other hand, in renewable energy communities, the members can be individuals, SMEs, and local authorities, including municipal administrations,

Figure 2.3  Timeline of regulatory evolution in Italy.

The current energy community implementation state in the EU 27 but likewise, participation in the energy community cannot constitute the main commercial or industrial activity for the members who benefit from it. The law underlines the concept of adherence to one of the two schemes on a voluntary basis using any collective legal entity type and among users connected to the same MV/LV substation. Also, it clarifies that the subjects participating in collective self-consumption or energy community initiatives produce energy for their own consumption with plants powered by renewable sources with a total power not exceeding 200 kW and newly installed – that is, entered into operation after March 1, 2020, and within 60 days following the date of entry into force of the provision implementing the Directive 2018/2001/EU. In this view, Article 36 of Directive 2018/2001/EU fixes the deadline for the transposition of the same directive by the member states to the end of June 2021 (Directive (EU) 2018/2001 of the European Parliament and of the Council on the Promotion of the Use of Energy from Renewable Sources, 2018), with consequent commissioning of the involved plants by August 2021. Moreover, Article 42-bis defines how the energy produced and shared should be treated: (a) the energy produced can only be shared using the existing distribution network; (b) the shared energy is equal to the minimum, in each hourly period, between the electricity produced by renewable systems and fed into the grid and the electricity taken from the grid by the associated end users; and (c) the energy is shared for instant self-consumption also through storage systems installed near the buildings/condominiums. In addition, the law clarifies the rights and duties of the members of an energy community, who regulate the relationships among them through a private contract that identifies also the manager of the shared energy. This subject can be an external consultant or, for instance, the administrator in condominiums, to whom the members delegate the management of payments and takings toward the sellers and the Italian Energy Services manager (Gestore dei Servizi Energetici – GSE) to this manager. In fact, the GSE plays a key role in providing access to the incentives aimed at favoring and encouraging the implementation of collective self-consumption and energy communities schemes. The second relevant body at national level is the Regulatory Authority for Energy, Networks, and Environment (Autorità di Regolazione per Energia, Reti e Ambiente – ARERA), which has established the requirements for having access to incentives and the calculation models to determine the fees to be paid by the GSE to collective self-consumers and members of energy communities with the Deliberate 318/2020/R/eel of August 4, 2020. Finally, with the ministerial decree of September 15, 2020, the Italian Ministry of Economic Development (Ministero dello Sviluppo Economico – MiSe) has characterized the incentives by defining the tariffs based on the transmission and distribution components of shared energy, thus taking into account the potential losses (Ministero delle imprese e del made in Italy, 2020). The incentives proposed involve 100 €/MWh of shared energy in the case of collective selfconsumption and 110 €/MWh for renewable energy communities. These incentives are recognized for a period of 20 years. They cannot be combined with those incentives provided by the foregoing decree of July 4, 2019, which promotes the use of electricity produced by onshore wind power, solar photovoltaic, hydroelectric, and

28  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi biogas plants (Decreto 4 luglio 2019 “Incentivazione dell’energia elettrica prodotta dagli impianti eolici on shore, solari fotovoltaici, idroelettrici e a gas residuati dei processi di depurazione” (in Italian), 2019), while they can be cumulated with tax bonuses within the limits established by the law. Thanks to this recent and rapid development of policies at national level, several projects aimed at establishing energy communities and collective self-consumption schemes are currently progressing in Italy. The leading energy community was established in the town of Magliamo d’Alpi, in northern Italy, in December 2020. The process was driven by the municipality, who installed a photovoltaic system on the roof of the town hall and is now the coordinator and the prosumer in the REC by sharing the energy produced. This small-scale REC provides a model that can be replicated in the numerous similar contexts existing in Italy. Indeed, this approach allowed the municipality to boost the spread of renewable energy systems installation, thus supporting local economic growth, and to fighting energy poverty, by sharing the value created with people in need of energy support. 3.3  Follow-up projects

In recent years, the European Union funding program Horizon 2020, among others, has acted as a strong facilitator in support of the progress and uptake of energy communities. In this way, the ZERO-PLUS project has been one of the forerunners to the numerous actions that are progressing toward the implementation of European energy communities and the generation and management of clean energy in all member states. Some of these research and coordination projects in progress that have a link with the ZERO-PLUS project are here briefly presented. However, this is not an exhaustive list of the several relevant research, innovation, and coordination actions related to this topic currently financed under the H2020 program. The H2020 project NRG2peers (H2020 Project NRG2peers, 2020), which stands for “Towards a new generation of EU peer-to-peer energy communities facilitated by a gamified platform and empowered by user-centred energy trading mechanisms and business models,” started in 2020 by taking the lead also from the lesson learned from the ZERO-PLUS project. Indeed, this project has the purpose of supporting the diffusion of the energy community model in Europe. It starts from existing virtuous cases, the so-called “innovators,” thus guiding the energy transition and the adoption of these models even in the “laggard” countries. To this aim, the project involves nine pilot cases, including “innovators” and pioneer energy communities, others that have been established at a later stage, and the “laggards,” including, for the aforementioned reasons, two Italian cases, managed by the University of Perugia together with the company EValTech (R&D of Elettrica Valeri SRL) and by Politecnico di Milano together with the municipality of Milan, respectively. The innovative and driving energy communities involved in the project are located in the Netherlands. The objective of the project is the creation of information and support desks at a Central European level, as well as at local level in the different involved countries, and the development of a gamified platform to support human-centric residential energy communities. Therefore, the focus is

The current energy community implementation state in the EU 29 on financial, legal, and technical feasibility in a short time, in order to support the adoption and replication of the proposed model throughout Europe. Another pilot case of this project is Luče Community, in Slovenia, which was born thanks to the H2020 COMPILE project (H2020 Project COMPILE, 2018), started in 2018. This project is focused on the decarbonization of energy supply and community building in energy islands. To this aim, the consortium developed different tools to design, manage, and support the successful achievement of this goal and tested them in real pilot cases. These tools involve, for instance, a toolset that helps operate, control, and manage a microgrid to improve its flexibility, stability, and security, or a building energy management application that engages users in the energy process by providing information on energy consumption, production, and sharing. Instead, the Lugaggia Innovation Community (LIC) (LIC, 2019) is a project launched by the University of Applied Sciences and Arts of Southern Switzerland (SUPSI) in 2019 to set up a self-consumption community to solve the issues in the public grid for the village of Lugaggia, Switzerland. This is done by integrating all building outlets in one grid, making use of a district battery, and implementing a community manager module that takes advantage of blockchain technology. This community has become one of the pilot cases of the H2020 project PARITY (H2020 Project PARITY, 2019), which is focused on the improvement of distribution grids by delivering a transactive grid and market framework. On the other hand, the H2020 CREATORS project (H2020 Project CREATORS, 2020), which stands for “CREATing cOmmunity eneRgy Systems,” addresses the side of community energy systems (CES) by supporting local stakeholders in the initiation, planning, implementation, and operation of CES throughout their entire life cycle. Moreover, business models will be defined based on technical and financial performance data to ensure commercial readiness and market uptake of these systems. Finally, the H2020 project SCCALE 20–30–50 (SCCALE 20–30–50 project to grow at least 25 energy communities – REScoop, n.d.) has been just recently started, with the aim to power and scale up energy communities around Europe. This will be done by exploring various community energy-enabling strategies, for example, collective self-consumption, building renovation, financing solutions, etc., and, thus, developing a series of tools and resources to support the establishment and operation of energy communities. The final goal is to boost the setup of at least 25 energy communities and 34 community projects. 4 Conclusion The energy transition toward clean energy and reduction of greenhouse gas emissions cannot be achieved only through markets and the development of increasingly advanced technologies. Indeed, energy transition implies, above all, a social transformation in which citizens have a key role. Citizens must be leading actors in this play thanks to the awareness of their role. To this aim, the distinctive characteristics of innovation and social transition of energy communities are the ability to combine mutual and public interest and the possibility of making decentralized renewable energies a “common good” pursued in collaboration with the different

30  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi stakeholders. Consequently, the potential for social innovation of energy communities also lies in the ability to involve consumers regardless of their income and social status, ensuring that the benefits obtained are shared even with those who cannot participate in their generation. If properly designed, energy communities will allow the reduction of energy poverty, thanks to the reduction of energy costs and the greater resilience of the scheme, breaking down the barriers that prevent the most vulnerable consumers from participating in clean energy sharing. In Italy, the “Milleproroghe” Decree first, and then the follow-up regulations, finally gave all citizens the opportunity to act as prosumers, namely, to collectively exercise the right to produce, store, consume, exchange, and sell self-produced energy, with the aim to contribute to environmental, economic, and social benefits for the same community. However, this is just the first step toward the energy and social transition of energy communities. Another fundamental step lies in the need to train new professionals – involved in the processes of design and management of the built environment – with respect to these new models of smart, resilient, and sustainable communities and cities. Therefore, detailed technical and operational guidelines for the design of efficient and effective energy communities – from the perspective of the citizen-prosumer, of the interested institutions, and of competent professionals – should be developed. Last but not the least, energy communities need the logistical support from technology providers. Indeed, currently, there is a lack of adequate and up-to-date expertise regarding technologies and services required to ensure their proper operation, for example, more flexible energy accounting mechanisms, which are currently meant for on-site exchange. Therefore, enabling technologies and services should be soon adapted to facilitate immediate, real-time, and easy-to-understand accounting for consumers and prosumers. Acknowledgments The authors wish to thank the Italian Ministry of Research for supporting the young researcher PRIN project NEXT.COM (20172FSCH4_002). Additionally, the authors would like to thank the Italian funding program Fondo Sociale Europeo REACT EU – Programma Operativo Nazionale Ricerca e Innovazione 2014–2020 (D.M. n.1062 del 10 agosto 2021) for supporting their research though projects “Efficientamento energetico e rinnovabili nella catena del freddo e nel sistema edificio-impianto,” “Red-To-Green,” and “Comunità energetiche resilienti per la valorizzazione del benessere ambientale, del risparmio energetico e della valorizzazione del patrimonio mediante gestione multidominio di dati human centric.” References Amin, A. Z. (2018). Decarb Europe Connecting Technologies for a Cleaner Future. Brussels: European Copper Institute (ECI). Candelise, C., & Ruggieri, G. (2020). Status and evolution of the community energy sector in Italy. Energies, 13(8), 1–22. https://doi.org/10.3390/en13081888

The current energy community implementation state in the EU 31 Caramizaru, A., & Uihlein, A. (2020). Energy Communities : An Overview of Energy and Social Innovation. Luxembourg: EU. https://doi.org/10.2760/180576 Cardinali, M., Pisello, A. L., Piselli, C., Pigliautile, I., & Cotana, F. (2020). Microclimate mitigation for enhancing energy and environmental performance of near zero energy settlements in Italy. Sustainable Cities and Society, 53, 101964. https://doi.org/10.1016/j. scs.2019.101964 Castaldo, V. L., Pisello, A. L., Piselli, C., Fabiani, C., Cotana, F., & Santamouris, M. (2018). How outdoor microclimate mitigation affects building thermal-energy performance: A new design-stage method for energy saving in residential near-zero energy settlements in Italy. Renewable Energy, 127, 920–935. https://doi.org/10.1016/j.renene.2018.04.090 de Waal, R. M., & Stremke, S. (2014). Energy transition: Missed opportunities and emerging challenges for landscape planning and designing. Sustainability (Switzerland), 6(7), 4386–4415. https://doi.org/10.3390/su6074386 Decreto 4 luglio 2019. (2019). Incentivazione dell’energia elettrica prodotta dagli impianti eolici on shore, solari fotovoltaici, idroelettrici e a gas residuati dei processi di depurazione (in Italian). Rome: Gazzetta Ufficiale della Repubblica Italiana. Decreto Legislativo 19 novembre 2021, n. 199. (2021). Attuazione della direttiva (UE) 2018/2001 del Parlamento europeo e del Consiglio, dell’11 dicembre 2018, sulla promozione dell’uso dell’energia da fonti rinnovabili (in Italian). www.gazzettaufficiale.it/ eli/gu/2021/11/30/285/so/42/sg/pdf Decreto-Legge 30 dicembre 2019, n. 162. (2019). Disposizioni urgenti in materia di proroga di termini legislativi, di organizzazione delle pubbliche amministrazioni, nonché di innovazione tecnologica (in Italian). www.gazzettaufficiale.it/eli/id/2020/02/29/20A01353/sg Directive (EU). (2018). 2018/2001 of the european parliament and of the council on the promotion of the use of energy from renewable sources. Official Journal of the European Union, 82. Directive (EU). (2019). 2019/944 on common rules for the internal market for eelectricity. Official Journal of the European Union, 18. Ecosystemic Transition Unit (ETU). (2020). Monachil | ETU Initiative. https://etuinitiative. eu/flagship/monachil/ Energy Transition: The Global Energiewende. (2021). Energy Communities: The Hidden Gems of the EU Energy Transition | Energy Transition. https://energytransition. org/2021/10/energy-communities-the-hidden-gems-of-the-eu-energy-transition/ European Commission. (2016). Evaluation Report covering the Evaluation of the EU’s Regulatory Framework for Electricity Market Design and Consumer Protection in the Fields of Electricity and Gas and the Evaluation of the EU Rules on Measures to Safeguard Security of Electricity Supply and Infrastructure Investment (Directive 2005/89) (pp. 1–178). Brussels: European Commission. European Commission. (2020a). Clean Energy for All Europeans Package. Official Website of European Commission. https://ec.europa.eu/energy/topics/energy-strategy/cleanenergy-all-europeans_en European Commission. (2020b). Energy Communities. Official Website of European Commission. https://energy.ec.europa.eu/topics/markets-and-consumers/energy-communities_en Frieden, D., Tuerk, A., Roberts, J., D’Herbemont, S., Gubina, A. F., & Komel, B. (2019). Overview of emerging regulatory frameworks on collective self-consumption and energy communities in Europe. 2019 16th International Conference on the European Energy Market (EEM), 1–6. https://doi.org/10.1109/EEM.2019.8916222 Gjorgievski, V. Z., Cundeva, S., & Georghiou, G. E. (2021). Social arrangements, technical designs and impacts of energy communities: A review. Renewable Energy, 169, 1138– 1156. https://doi.org/10.1016/J.RENENE.2021.01.078

32  Anna Laura Pisello, Cristina Piselli, and Benedetta Pioppi GSE. (2019). Accesso agli incentivi (in Italian). Roma: Gestore dei Servizi Energetici. H2020 Project COMETS. (2019). Collective action Models for Energy Transition and Social Innovation. www.comets-project.eu/ H2020 Project COMPILE. (2018). Integrating Community Power in Energy Islands. www. compile-project.eu/ H2020 Project CREATORS. (2020). Creating Community Energy Systems. www.crea tors4you.energy/ H2020 Project NRG2peers. (2020). Towards a New Generation of EU Peer-to-Peer Energy Communities Facilitated by a Gamified Platform and Empowered by User-Centred Energy Trading Mechanisms and Business Models. https://nrg2peers.com/ H2020 Project PARITY. (2019). Pro-sumer AwaRe, Transactive Markets for Valorization of Distributed flexibilITY enabled by Smart Energy Contracts. https://parity-h2020.eu/ H2020 Project ZERO-PLUS. (2015). Achieving Near Zero and Positive Energy Settlements in Europe using Advanced Energy Technology. www.zeroplus.org/index.php/ Legge 28 febbraio 2020, n. 8. (2020). Conversione in legge, con modificazioni, del decretolegge 30 dicembre 2019, n. 162 (in Italian). www.gazzettaufficiale.it/eli/id/2020/02/29/ 20G00021/sg LIC. (2019). LIC Project. https://lic.energy/ Mavrigiannaki, A., Gobakis, K., Kolokotsa, D., Kalaitzakis, K., Pisello, A. L., Piselli, C., Laskari, M., Saliari, M., Assimakopoulos, M.-N., Pignatta, G., Synnefa, A., & Santamouris, M. (2021). Zero energy concept at neighborhood level: A case study analysis. Solar Energy Advances, 1, 100002. https://doi.org/10.1016/J.SEJA.2021.100002 Ministero delle imprese e del made in Italy. (2020). Energia, incentivo per l’autoconsumo e le comunità energetiche da fonti rinnovabili (in Italian). Rome: Istituto Poligrafico e Zecca dello Stato. Piselli, C., Salvadori, G., Diciotti, L., Fantozzi, F., & Pisello, A. L. (2021). Assessing users’ willingness-to-engagement towards net zero energy communities in Italy. Renewable and Sustainable Energy Reviews, 152, 111627. https://doi.org/10.1016/j.rser.2021.111627 Quaranta, A. (2020). Comunità energetiche in Italia: prove di sostenibilità diffusa (in Italian). TEKNORING, Il Portale Delle Professioni Tecniche. Reda, F., & Tuominen, P. (2020). IEA EBC Annex 83 – Positive Energy Districts. https:// annex83.iea-ebc.org/ Ren, L., Wang, W., Wang, J., & Liu, R. (2015). Analysis of energy consumption and carbon emission during the urbanization of Shandong Province, China. Journal of Cleaner Production, 103, 534–541. https://doi.org/10.1016/j.jclepro.2014.08.098 Rescoop. (2019). Q & A: What Are Citizen and Renewable Energy Communities? www. rescoop.eu/toolbox/q-a-what-are-citizen-and-renewable-energy-communities Roberts, J., Frieden, D., & D’Herbemont, S. (2019). Energy community definitions (Issue May). COMPILE: Integrating Community Power in Energy Islands. https://www.com pile-project.eu/ SCCALE 20–30–50 Project to Grow at Least 25 Energy Communities – REScoop. (n.d.). www.rescoop.eu/news-and-events/news/sccale-20-30-50-project-to-grow-at-least-25energy-communities Stichting, S. (2020). De meest duurzame drijvende wijk van Europa. Amsterdam: Schoonschip

3

Methodology: the ZERO-PLUS approach Morna Isaac and Shabtai Isaac

1 Introduction The ZERO-PLUS approach is a modular and collaborative solution that supports and informs the design and construction of new residential net-zero energy settlements (hereafter referred to as “NZES”). The term “settlement” is used loosely here, referring to anything from a small number of residences up to the neighborhood level. Thus, we use the term settlements in order to differentiate the ZEROPLUS approach both from approaches dealing with single residential buildings such as Passivhaus and from approaches addressing the planning of whole cities. Research performed by ZERO-PLUS project consortium members (Isaac et al., 2020) indicates that this settlement level is the optimal level for planning to achieve cost-effective net- or near-zero energy performance of residential buildings. We use the terms “ZERO-PLUS approach,” “ZERO-PLUS concept,” and “ZERO-PLUS framework” to refer to the settlement-level optimization method and the toolkit developed in the EU H2020 ZERO-PLUS project, which together aim to address issues affecting the design and construction supply chain, overcoming barriers to the cost-effective construction of NZES. The method and toolkit integrate design and construction considerations in the planning of settlements, including the selection of suitable technologies. The main aim is a reduction of energy consumption, construction delays, initial and operational costs compared to conventional individual homes. In addition to its cost-saving approach to settlement-level design, one of the competitive advantages of the ZERO-PLUS concept is its ability to continuously inform energy management at the settlement level, using real-time analysis of data on energy production and consumption. The targets to be achieved by applying the ZERO-PLUS approach can be adjusted as needed for specific cases. Encouraging innovation in the conservative construction industry is a difficult task. To accomplish this, in the development of the ZERO-PLUS concept, emphasis is put on the promotion of a new way of thinking. We aim to provide the market with strategies that can be employed to reduce the resistance to change and contribute to a continent-wide market uptake of net-zero energy buildings and settlements. The ZERO-PLUS approach will make it easier for the construction industry

DOI: 10.1201/9781003267171-3

34  Morna Isaac and Shabtai Isaac to quickly adopt technologies and processes that can increase the energy efficiency of its products. 2 What is the ZERO-PLUS approach? The ZERO-PLUS approach can help overcome the barriers in adopting energy performance standards in building design and construction. Traditional obstacles have affected the ability of stakeholders to implement such standards in a way that is cost-effective and delivers the expected results. This section delves into the barriers, value preposition, and advantages offered by the ZERO-PLUS approach. 2.1  Barriers addressed by the ZERO-PLUS approach

Three main categories of barriers to the successful construction of net-zero and positive-energy communities in Europe are addressed: 1. Standard construction methods can result in cost overruns and in design targets being missed. 2. NZEBs are still more expensive to build than conventional buildings, despite the requirement of the European Union Energy Performance of Buildings Directive (EPBD) that all new buildings from 2021 (public buildings from 2019) have to be NZEBs. 3. Lack of coordination and collaboration among different actors in the construction supply chain. An example of such lack of coordination is the difficulty of assessing the feasibility of the installation of innovative technologies in specific cases. The ZERO-PLUS approach includes a method and accompanying tools that provide an overarching solution mitigating the barriers to successful construction of net-zero energy settlements (NZES) in Europe. Based on this approach, a service supporting design, commissioning, and monitoring of NZES could be provided. Focusing on the settlement level, the ZERO-PLUS approach aims to bring together technology suppliers, energy efficiency and renewable energy experts, and developers who work together from the earliest stages of project conception to optimize the NZES design. This collaborative management approach leads to an increased ability of actors to simultaneously design the settlement and plan its construction, resulting in lower energy consumption and cost reductions. In addition, greater energy efficiency and economies of scale can be achieved through a transition from single NZE buildings to NZE settlements in which the energy loads and resources are optimally managed. 2.2  Value proposition

ZERO-PLUS is a comprehensive, cost-effective system for the design, construction, and monitoring of NZES which has been tested and implemented in four pilot

Methodology: the ZERO-PLUS approach 35 projects across Europe. ZERO-PLUS provides the market with an innovative yet readily implementable combination of services and tools for designing and building NZE residential neighborhoods that will significantly reduce both their initial and operational costs. It was born from a vision aiming to simplify the design and construction process of highly energy-efficient buildings by using an integrated, iterative, and collaborative approach to design and construction management. Consequently, the ZERO-PLUS concept can deliver the following: • Housing that achieves renewable energy and energy savings targets set by the recipient at the lowest possible cost. • Clear information on the trade-offs between cost and performance. • Provision of the information needed for optimal, cost-effective maintenance of completed buildings. Cost reduction is achieved through the careful selection of innovative technologies that increase the efficiency of building components providing energy conservation and energy production in settlements. This reduces initial costs by allowing, for example, less material and space to be used for energy conservation and energy production. Technology selection is addressed through technology scouting at the design phase. Examples of technology types considered range from improved insulation, innovative HVAC, to efficient wind and solar energy-producing components. The required levels of performance are achieved through a carefully calibrated combination of investments in energy efficiency measures (e.g., through improved insulation) and investment in renewable energy technologies. 2.3  Benefits of the ZERO-PLUS approach

The benefits that can result from the implementation of the ZERO-PLUS approach are described in Figure 3.1.

Figure 3.1  Benefits of the ZERO-PLUS approach.

36  Morna Isaac and Shabtai Isaac The specific benefits that accrue to the main stakeholders include: For developers (housing associations, private housing developers, or municipalities), applying the ZERO-PLUS concept leads to: • Reduced cost of construction compared to other NZE buildings. • Provision of a clear road map for achieving compliance with European regulations for energy efficiency in buildings. • Improved energy performance of the building reduces energy costs for residents, an added incentive to purchase or rent a ZERO-PLUS home. • Due to the guaranteed energy performance and increased comfort for residents, homes in NZES have a marketing advantage compared to marketing conventional dwellings. • Ease of contracting and clear procedures resulting in time and financial savings. • Enhanced reputation and image of the organization due to being involved in cutting-edge projects and delivering high-quality housing. For construction actors, including construction companies, professionals, technology providers, and installers, benefits include: • Increased sales of energy efficiency products or services. • Reduced cost of construction. • Integration of the construction supply chain, resulting in fewer delays and better cost control. • Enhanced ability for new actors to enter the market via the provision of clear guidelines and practices. • Contributing to innovation and improvement of processes in the construction industry. • Simplified integration of renewable energy and energy efficiency measures in the settlement. For end users (residents, homeowners, maintenance companies, and utilities), benefits include: • • • •

Energy savings. Enhanced quality of life. Increased energy security. Ease of carrying out maintenance activities, resulting in time and financial savings.

3 Elements of the ZERO-PLUS approach The ZERO-PLUS approach has three phases (design, construction, and occupancy), with each having its own set of activities. The phases are shown in Figure 3.2.

Methodology: the ZERO-PLUS approach 37

Figure 3.2  Overview of the phases of the ZERO-PLUS approach.

3.1  Design phase

In the ZERO-PLUS concept, the design phase comprises the planning and design of the individual buildings and the settlement as a whole. An emphasis is placed on planning all design strategies and all the technologies to be installed at the settlement level. Due to economies of scale, this approach enables the hiring of experts, which would not have been affordable in the context of a single-building project. Using state-of-the-art simulation tools, energy generation and consumption projections are estimated – first, at the building level, and then at the settlement level – to assess the energy performance. The simulation considers a certain set of promising and innovative technologies. The microclimate in the settlement is also assessed to determine the future needs of each building, and together with the building-level assessments, this informs the design of indoor and outdoor living spaces. After the production of an initial integrated design optimizing building thermal efficiency and minimizing construction costs, an additional assessment is carried out using life cycle cost analysis (LCCA) to determine the costs to be incurred by operating the energy and systems chosen for the settlement. The cost analysis is based on the applicable regulation, such as net-metering regulations. Continuous iteration and refinement of the initial technology set were done to achieve optimal performance and cost-effectiveness. The final step of the design phase revolves around the development of the design, commissioning, and monitoring and verification (M&V) plans. The building commissioning plan includes the final selection of monitoring devices to be installed, provides installation guidelines for the energy and environmental systems, details the tendering process to be followed to support construction that is timely and within budget, and lists all thermal, visual comfort, and indoor air quality parameters to be monitored during the occupancy phase. This activity illustrates the core aspects of the ZERO-PLUS concept: integration, optimization, holistic planning and design for performance, and cost-effectiveness.

38  Morna Isaac and Shabtai Isaac 3.2  Construction phase

At every step of the construction phase, collaboration and synchronization of the work performed by the different construction actors are ensured by following the detailed commissioning plan prepared in the previous phase. A change management (CM) tool is used that enables the identification, examination, and modification of every proposed change to the design of the building. The tool prevents discrepancies in construction resulting from a lack of communication between different actors and allows optimization of the as-built energy and financial performance of components. As the construction of the building progresses, energy efficiency (EE), renewable energy (RE), and monitoring components are integrated into the building structure following the guidelines laid out in the commissioning plan. The commissioning plan also ensures compliance with local regulations as well as the local building code for the seamless integration of the building into the local landscape. Once the installation of energy systems is completed, functional testing takes place to ensure any deficiencies are handled according to the commissioning plan. Checklists are provided to construction contractors and developers to facilitate this process ahead of the occupancy phase. Pre-occupancy checks are then carried out by the construction supervision team, which verify the complete and correct installation of monitoring devices, energy measurement devices, weather stations, and routers collecting energy load data at the building and settlement level. Further tests are conducted to assess the thermal and physical performance of the building structure for heat loss, permeability, and U-value. The building and/or settlement is then delivered “turnkey,” ready to be sold or rented. 3.3  Occupancy phase

Three months after the start of occupancy, activities relating to the occupancy phase begin. The process of documentation, collection, and analysis of data at the building and settlement level is enabled using a WebGIS platform, which is accessible to all stakeholders involved in the ownership, operation, and maintenance of the building. The data gathered will be adapted to the needs of each individual case. They can include climatic data (site-specific, weather, building design, fenestration, and orientation) and, where needed, other quantitative and qualitative data on the residents/homeowners and their use and operation of the building. Using a post-occupancy evaluation (POE) protocol, the analysis of the data generated will enable an optimal allocation of funds for the maintenance of the buildings and settlement. Residents and maintenance companies help achieve the energy and environmental impacts of the buildings by reporting any malfunctioning equipment. Data on thermal, visual, and acoustic data and indoor air quality, and their relations to comfort votes, can be captured by sensors fitted on and in every building if the developer chooses to do so and through surveys with the building users. At the settlement level, an energy management dashboard tracks energy production and demand.

Methodology: the ZERO-PLUS approach 39 To facilitate the monitoring process, the supplier of each energy or environmental technology will have to provide a fully detailed operations and maintenance manual, and residents will be provided with a “welcome package” to introduce them to the innovative technologies enhancing their quality of life. Guidelines on how to access and operate the WebGIS platform will be provided to all stakeholders involved in the operational management of the settlement. 4 Detailed description of the ZERO-PLUS approach The activities and tools that support each of the phases of the ZERO-PLUS approach are shown in Figure 3.3. At the top of the diagram, in gray, we show the toolkit developed. In the body of the diagram we show the main steps of the approach. Linkages between the steps are shown by arrows. The steps shown in the diagram include the following activities. 4.1  Design phase

• Step 1.1: Preparatory activities. Data will be collected (wind maps, irradiation data) to plan the use of materials and technologies for outdoors, such as renewable energy production, energy management, and environmental control, to be implemented in common areas of the settlement. • Step 1.2: Setting objectives and technology scouting. The expected performance of technologies for energy management and production will be defined. The expected energy performance of the buildings is defined based among other factors on relevant regulations, such as those for net metering. Energy definitions are set. Data that will be monitored are agreed upon.

Figure 3.3  Activities and tools supporting each phase of the ZERO-PLUS approach. Source: Mavrigiannaki et al. (2021).

40  Morna Isaac and Shabtai Isaac • Step 1.3: Building-level simulation; Step 1.4: Settlement-level simulation. Energy conservation measures and renewable energy technologies as well as settlement servicing technology are modeled along with simulations of mitigation of microclimatic conditions. A tool for simulation of energy technologies and renewable systems at settlement scale is developed with the purpose of determining whether or not the hourly energy requirements of each building in the settlement can be covered by a specific combination of the different energy technologies and renewable systems within the settlement itself. • Step 1.5: Initial integrated design (minimizing construction costs). Energy and initial cost analysis to select the combination of technologies to be implemented in the project at the building and settlement level and customization of monitoring protocols. • Step 1.6: Optimization of design – integrated optimization. At the building level, the energy and financial performance of the settlement design is ensured through an iterative process. LCCA is used to determine life cycle costs of the innovative energy and environmental systems used in the settlement. At the settlement level, renewable energy production technology and settlement servicing technology are modeled together with simulations of microclimatic conditions. This step also informs the design of outdoor common spaces. • Step 1.7: Assembly and installation planning. Specific tasks include: • Design coordination, including interface checking and clash detection. • Conservative preliminary cost assessment and appropriate budget reserves. • Creation of detailed site plans, including the work breakdown structure and a location-based schedule. • Quality control and verification of the design. • Step 1.8: Final design and preparation of commissioning. The design of the building commissioning plan and measurement and verification plan, including final selection of the monitoring devices to be installed in the buildings, will inform the tendering process to ensure the timely conduct of specific technical tasks during the construction phase. Development of monitoring protocols and procedures to control and optimize environmental conditions of projected NZE settlement will be customized to match the microclimatic conditions of the settlement. Each building and settlement includes sensors to obtain monitoring data to check on the targets that ZERO-PLUS aims for. The data collected can include thermal comfort and indoor air quality, which will be analyzed using the WebGIS platform. The development of the monitoring platform will include: • Assessment of the performance of involved systems and technologies and environmental performance of the ZERO-PLUS settlements. • Generation of technical information to inform future feasibility studies and designs.

Methodology: the ZERO-PLUS approach 41 4.2  Construction phase

• Step 2.1: Construction management. This process is to ensure that installation instructions and commissioning process are followed and works are going according to plan. The construction manager is responsible for all construction contractors and for liaising with technology providers as needed. • Step 2.2: Cost control and change management. Synchronized and collaborative work between different technology providers, developers, and work package leaders. The change management (CM) tool will allow to identify, examine, and discuss every proposed change that may have an impact on energy performance and/or operational costs. • Step 2.3: Inspection and installation of energy efficiency, renewable energy, and monitoring equipment. The main purpose of this step is to provide key guidelines and support the owners of each settlement following the detailed commissioning process to ensure the proper implementation of the selected innovative technologies in ZERO-PLUS and help them in navigating through this complex process. • The activities performed in this step are to ensure the applicability and compliance of chosen technologies with local standards and code, to provide installation guidelines to construction actors, and to monitor the performance of installed technologies in order to detect and address any deficiency found before the occupancy phase. • Step 2.4: Functional testing. Checklists will be provided to developers to check the correct implementation of each technology and to detect deficiencies while construction is taking place, before the pre-occupancy checks. Reports will be issued by the supervision team, and responses from contractors will be tracked to ensure all contractors handle deficiencies on time and according to the commissioning plan • Step 2.5: Pre-occupancy checks. Pre-occupancy checks will be carried out by the supervision team and will verify the complete and correct installation of monitoring devices, energy measurement devices, weather station, and routers collecting energy production and consumption data. A number of different tests to evaluate the physical performance of the building envelope for heat loss will also be carried out after the completion of the construction (i.e., air permeability and U-value tests). 4.3  Occupancy phase

• Step 3.1: Post-occupancy evaluation (POE). Starting three months after early occupancy at the earliest. Process for documentation, collection, study, and analysis of settlement data. Tools and processes used include surveys, questionnaires, and interviews. Data will be collected regularly, covering different seasons and times of the day, and will include site-specific, weather, building design, fenestration, and orientation data. Other subjective building user data will include gender, age, country of origin, health status, education, and

42  Morna Isaac and Shabtai Isaac occupation. Questionnaires need to be calibrated to accommodate for cultural discrepancies. The analysis will inform projections used to adjust investments and therefore promote an enhanced allocation of funds for the maintenance of the settlement. • Step 3.2: Monitoring and verification (M&V). End users (residents and maintenance companies) take part in the monitoring and help achieve the impacts by keeping an eye out for malfunctioning of systems and identifying potential improvements. Each building and settlement has sensors to monitor data on thermal comfort, visual comfort, and indoor air quality. At the settlement level, an integrated resources management system and dashboard allow for verification of energy demand and production, therefore enabling close monitoring of the energy load. • Step 3.3: Maintenance. The supplier of each technology will provide a fully detailed operations and maintenance manual. A problem identification procedure has been developed to detect and deal with issues that may arise. Technology providers and developers will provide support as needed. Building occupants will receive a “welcome package” to introduce them to the innovative technologies and monitoring equipment installed in their home and settlement. Guidance on how to access the WebGIS platform and how data will be collected and monitored will be provided. It should be noted that occupants are not expected to interact with the ZERO-PLUS technologies, apart from thermostats. 5 Drivers and barriers 5.1  Barriers to the uptake of NZES

Following a survey conducted among the members of the ZERO-PLUS consortium, key barriers to the uptake of NZE technologies and settlements were categorized (Mavrigiannaki et al., 2021) as follows: • Technological barriers. Project participants noted a shortage of the skills and expertise needed for the construction of NZES throughout the construction sector, combined with uncertainties on how new technologies perform. Some of these technologies, such as solar panels and insulation, may need to be adapted to site constraints, architectural requirements, and specific local standards. • Economic and financial barriers. At the European and national level, the lack of access to affordable finance to build new residential homes meeting high standards represents an important barrier, while higher initial costs can also be a limiting factor. • Regulatory and legislative barriers. Actors involved in construction are unclear about the legal definition of NZEB, while there is lack of policy coherence at the national level. • Market organization barriers. The high numbers of parties involved (from architects and engineers to contractors, owners, and tenants) in building construction and operation all have different and conflicting financial motives that

Methodology: the ZERO-PLUS approach 43 discourage investment in innovative, energy-efficient building designs and discourage a collaborative approach to construction. • Awareness and knowledge barriers. The lack of awareness of existing solutions by professionals is exacerbated by the lack of mainstream examples of good practice and reliable data from homes with high energy performance. • Institutional barriers. The construction industry is a conservative one, and the many changes in practices required for the construction of NZES are resisted by many in the sector. • Social and behavioral barriers. The behavior of residents has a major influence on energy use in homes and on the achievement in practice of net-zero or positive-energy targets. From the point of view of suppliers, a key barrier identified is the unsuitability of conventional procurement practices for construction projects aiming to achieve netzero targets. An internationally recognized and cost-effective procurement method that can address this barrier is energy performance contracting (EPC). However, the use of EPC in new construction faces challenges due to the split responsibilities of parties responsible for the optimization of the energy design of the building. The ZERO-PLUS approach, with its information-sharing and enhanced communication and collaboration between parties, could address these challenges. The construction of a ZERO-PLUS settlement, with its higher cost and longterm commitment compared to conventional buildings, is facilitated by using innovative procurement strategies. By carefully considering procurement needs from the outset of the construction process as part of the development of the commissioning plan, companies reduce transaction costs, which can create room for investment in other aspects of construction, such as higher energy performance. 5.2  Drivers for the construction of residential NZES

The following key drivers and barriers for the construction of residential NZES were identified through the analysis of the supply chain in the construction industry: • Legislation. Although there are large discrepancies between the definitions of low-energy buildings in different European countries, the EPBD and other EU directives as well as their transposition to national legislation are perceived as key drivers. • Demand. Considering that the goal set by the EPBD is that every new building (public and residential) must achieve NZEB standards, it can be assumed that this drives an increase in market demand. • Financial drivers. A number of different financial drivers exist due to the reduction of energy-related operational costs compared to conventional buildings. Financial support mechanisms exist at the EU level, which support market growth (such as, for example, ELENA and the European Energy Efficiency

44  Morna Isaac and Shabtai Isaac Fund). At the national level, a diversity of financial incentives exists, with some targeted at companies and some at consumers, but both types aim to incentivize demand and boost construction. Feed-in tariffs (FiT) are an example of financial mechanisms which have proved decisive in the integration of renewable energy sources in buildings. • Public sector support. Distinguished from pure legislation, this refers to demonstration programs, research, communication, and education of various groups. Public sector support may be particularly important when it is translated to semi-public institutions, such as housing associations. • Awareness and knowledge. Awareness of actors in the supply chain of requirements and solutions to build NZES, and awareness of consumers of the advantages of highly energy-efficient homes over a conventional house, such as cost-efficiency and comfort. Some additional drivers have been identified but depend to a large extent on the type of developer, such as: • Private building developers may turn to building highly energy-efficient homes, provided that the investment cost is equal, or lower, than for the construction of a conventional building. • Housing associations. Reducing energy expenses is believed to lead to improvements in rent collection, while corporate social responsibility and the reduction of fuel poverty are also a consideration reported by both UK and French associations. • Private landowners and self-builders may see highly energy-efficient homes as a marker of quality. 6 Potential for commercial exploitation A commercial offering based on the ZERO-PLUS approach could take advantage of the drivers noted in the previous section and mitigate many of the barriers to the construction of NZES. 6.1  Target markets

The target market of ZERO-PLUS is the European construction market, in particular, the European construction market for new highly energy-efficient buildings, especially new residential settlements. The target audience of the ZERO-PLUS concept are organizations with the resources to develop whole settlements and with ambitions to invest in developments with high environmental performance. Since the construction of a settlement requires significant resources, the main contractors involved in building ZERO-PLUS settlements would have to come from the small number of medium or large companies in the construction sector, with micro and small companies participating as subcontractors or some other form of collaboration.

Methodology: the ZERO-PLUS approach 45 Indicative customer segments for the ZERO-PLUS approach could be: • Large or growing municipalities aiming for excellence in residential construction who would adopt a holistic methodology of planning and managing urban expansion in the most sustainable way. • Housing associations with environmental commitment who aim to provide the beneficiaries with highly efficient, environmentally friendly, and low-carbon buildings. • Private or public housing developers investing in multi-building residential developments who wish to leverage compliance with the EPBD and improve performance and design. • Professional architecture/engineering practices, which would adopt a comprehensive service and toolbox package for the design of NZE settlements and the management of the construction and commissioning phases. 6.2  Potential promoters

Three main initial channels could be envisaged to be targeted by a ZERO-PLUS commercialization strategy. These indicative channels could be: • Real estate developers. Both private and public housing developers maintain a good relationship with construction actors, have the capacity to reach out to a variety of contacts, as well as a capacity to invest and unlock capital. • Building planners. Architects, urban planners, and designers represent points of entry to advocate for the ZERO-PLUS concept to be applied to building and settlement construction projects. • Policymakers. To various extents, policymakers at different levels have the capacity to influence other stakeholders, in addition to a capacity to leverage funding. Their decision-making processes could also be informed by their familiarity with ZERO-PLUS and by the data generated by ZERO-PLUS settlements. 6.3  Potential business model

Several potential directions for commercial exploitation of the tools and methodology that form the ZERO-PLUS approach were identified. These included the development of a settlement-level energy-efficiency standard, development of a settlement passport (similar to building-level certificates such as LEED or BREEAM), creation of a ZERO-PLUS toolkit, or the formation of a company that would provide services using the approach. The most promising business model was judged to be that of a service for net-zero energy settlement design, commissioning, and monitoring. The application of this concept would result in new housing that achieves specific renewable energy and energy-saving targets at the lowest possible cost for the technologies considered. This would be achieved through the implementation of the ZERO-PLUS approach: an iterative, integrated optimization process that looks at both the energy

46  Morna Isaac and Shabtai Isaac and the financial performance of the design. Tools would be provided, based on the tools developed for ZERO-PLUS, to ensure that construction is completed on budget and while achieving design targets. After the commissioning of the buildings, all information needed for optimal maintenance would be provided to building managers. The service would combine the knowledge and tools of a range of entities with broad expertise in design, modeling, construction management, and monitoring of buildings into a seamless package as developed for the ZERO-PLUS project. The economies of scale provided by working at the settlement level would lead to a reduction of costs compared to working at the single-building level. 7 Conclusions In conclusion, the analysis of the market for residential highly energy-performing buildings in the EU showed that the ZERO-PLUS approach can help overcome some major barriers to the design and construction of NZEBs and NZESs. The ZERO-PLUS project’s outputs were used to develop a concept for commercial exploitation which is flexible and can be expanded to other target markets. To do this, we analyzed the ZERO-PLUS project’s activities and outputs and developed a description of the ZERO-PLUS concept, illustrating the steps involved in applying the concept and the tools used. These steps and tools could be further developed into the product and service offering proposed earlier. The ZERO-PLUS concept is flexible, and successful commercial exploitation of the ZERO-PLUS project outputs could be followed by an expansion to additional target markets. Examples are mixed-use developments, including commercial and/ or industrial buildings, as well as residential ones, and a geographical expansion to application in other regions of the world. The ZERO-PLUS concept’s optimization component and modular nature make it relevant to different climatic conditions (i.e., colder and hotter climates) and regions throughout Europe, as well as to other regions in the world with a high or increasing demand for energy-efficient buildings. References Isaac, S., Shubin, S., & Rabinowitz, G. (2020). Cost-optimal net zero energy communities. Sustainability, 12(6), 2432. Mavrigiannaki, A., Pignatta, G., Assimakopoulos, M., Isaac, M., Gupta, R., Kolokotsa, D., Laskari, M., Saliari, M., Meir, I. A., & Isaac, S. (2021). Examining the benefits and barriers for the implementation of net zero energy settlements. Energy and Buildings, 230, 110564.

4

Part 1: UK case study Rajat Gupta, Matt Gregg, and Owen Daggett

1

Background and context

The UK has transitioned through several policy initiatives during the time frame of the housing development at the center of the UK ZERO-PLUS study (CCC, 2019). At the time of the origination of the development, the UK government had in place a legally binding target of 80% CO2 emission reduction (from 1990 levels) by 2050 (signed in 2008) (UK Government, 2019). In 2019, the national target was revised to achieve net zero emissions by 2050 (BEIS, 2019). The ZERO-PLUS (ZP) dwellings are located in the Derwenthorpe development located on the outskirts of York, England. York, located in the North of England, experiences a temperate climate, resulting in average winter temperatures between 1°C and 5°C, and average summer temperatures between 11°C and 18°C. As a result, there was a greater focus on heating demand in the properties, with a total of 1,975 heating degree days compared to 298 cooling degree days. Derwenthorpe began construction in late 2010 and is currently still under construction, with phase 5 in progress in 2021. The development of around 500 homes includes two-, three-, four-, and five-bedroom family homes and several onebedroom apartments. The scheme was developed on 54 acres, with around 18 acres of open land available for the community, with recreational open space being a key feature of the development. In addition to the public open space, all single-family homes were designed with a private garden. The development was designed to be ‘environmentally friendly’ and energyefficient. One initial key aspect of this was that all homes built were expected to meet or exceed the Code for Sustainable Homes level 4 standard (CSH4) (DCLG, 2006, 2008). To this end, all homes were designed to include several features that would qualify them for CSH4, including high levels of airtightness/insulation, lowenergy fittings, water restrictors, and mechanical ventilation with heat recovery (MVHR) (Quilgars et al., 2019). Additionally, hot water and central heating are provided to all homes by means of a centrally located district heating system. Some key changes were made in later phases for capital cost reasons and experiences of operational difficulty from both a management and resident viewpoint. One notable change was that the MVHR system for ventilating homes in phase 1 was replaced by mechanical extract ventilation (MEV) in later phases. The district DOI: 10.1201/9781003267171-4

48  Rajat Gupta, Matt Gregg, and Owen Daggett heating system is fueled by gas, though it was originally intended to be a biomass system. As a result of revisions to the overall plan, beginning with phase 2, homes were designed to only meet CSH level 3 (Quilgars et al., 2019). This chapter is the first in a two-part series on the UK ZERO-PLUS dwellings. It describes the case study dwellings, methods, results, and outcomes from the design, optimization, delivery, monitoring, and evaluation of the ZERO-PLUS dwellings in the UK. The second part describes the modeling and simulation phases and processes in greater detail. The following section of this chapter introduces the case study dwellings; Section 3 describes the methodological approach to each phase of the project, Section 4 the design process, Section 5 the delivery of the project, and Section 6 the operation of the dwellings, specifically the evaluation of one year of occupancy. The final section provides a concluding discussion to the chapter. 2 The case study dwellings The developer for the project selected three dwellings to be improved through the ZP project. The dwellings were constructed in phase 4 of the development, which began construction in early 2016. ZP1 and ZP2 are both two-bedroom semidetached properties consisting of two stories. These two properties are mirrored, and both share the party wall along the lounge wall. ZP3, separated from the others by a 2 m passage, is a three-bedroom, plus-study detached property with an attached garage, also with two stories. Figure 4.1 shows the three dwellings from the street. Detailed dwelling construction specifications are presented in Chapter 4 Part 2.

Figure 4.1  Street frontage of the ZERO-PLUS dwellings.

4.1: UK case study 49 3 Methodology The project was split into four main phases: 1. Modeling, simulation for design specification adjustment (December  2015– July 2016) 2. Cost optimization and technology integration planning (August 2016– December 2017) 3. Construction (January 2018–March 2019) 4. Building performance evaluation (BPE) (April 2019–August 2020) 3.1  Modeling, simulation, and cost optimization

The research team was provided with design and specifications for the dwellings as typical Derwenthorpe designs. At this point, the research team began testing energy technology options through modeling and simulation. The overall objective of the modeling and simulation phase was to revise the design of the original dwellings to achieve energy consumption and generation key performance indicators (KPIs) of the ZERO-PLUS project. These were: • Net-regulated1 energy consumption to be less than or equal to 20 kWh/m² per year. • Total renewable energy (RE) generation to meet or exceed 50 kWh/m2 per year. As location, orientation, form, size, and style of the dwellings were fixed, improvement was dependent on technological advancements. The ZP project had the goal of applying and testing energy efficiency and renewable energy generation technologies that are an advance beyond the state of the art. These were: • Advanced insulation. High thermal resistance and high solar reflectance extruded polystyrene external insulation. • Advanced HVAC. Solar desiccant evaporative cooling. • Building energy management system (BEMS). Smart home energy management. • biPV. Precast, dry-assembled, and pre-stressed translucent, building-integrated PV components made of dye-sensitized solar cells–integrated glass blocks. • Solar PV and thermal CHP (CHP/PV). Optics technology used to focus the sun’s radiation on a small area occupied by high-efficiency photovoltaic cells to generate electricity and capturing waste heat. • Wind/PV. Building-based modular PV and wind turbine–integrated system. • Pressurized oil storage. Thermal energy storage.

1 Regulated energy = space heating + cooling + ventilation + domestic hot water (DHW) + fans + pumps.   Regulated energy does not include plug loads (e.g., lighting and appliances).   Net-regulated energy = (regulated energy) − (renewable energy generated).

50  Rajat Gupta, Matt Gregg, and Owen Daggett The specific details of the modeling and simulation phase of the project are described in Chapter 4 Part 2. 3.2  Cost optimization

As costs were a real concern, optimization was the next step in the project. Cost optimization entailed gathering costing data from technology producers and modeling alternatives. The cost optimization KPI of the ZERO-PLUS project was: • The investment cost of the technological advancements to achieve the preceding KPIs is greater than or equal to 16% less than that of a comparable net-zero energy building (NZEB). 3.3  Building performance evaluation

Following construction of the dwellings, the evaluation phase was split into two areas. These were pre-occupancy testing and post-occupancy monitoring and evaluation. 3.3.1 Pre-occupancy testing

The objective of the pre-occupancy testing was to check the actual thermal performance of the building fabric and identify any areas of air leakage, thermal bridging, or less-than-adequate insulation in the external fabric. The approach was to use integrated building fabric performance tests with some degree of longitudinal evaluation. The BPE methods included: Air permeability (AP) tests were performed immediately following construction for compliance purposes (January–February 2019) and again in April 2019. The tests were conducted on each of the three dwellings in accordance with ATTMA TSL1 (Air Tightness Testing and Measurement Association Technical Standard L1) recommendations, using a blower door and depressurization pressures up to 50 Pa. Thermal imaging was carried out on April 3, 2019. At that time, the weather conditions were not ideal due to limited cloud cover, allowing some incident solar radiation on the building fabric. For this reason, the survey was restricted to interiors only. Depressurization was used to highlight areas of air leakage. A blower door was used, and a pressure of approximately −50 Pa was maintained for a period of 15 min before a second thermographic survey was undertaken. A 19°C difference was maintained between interior and exterior. Heat flux plates were installed for 14 days (April 3–24, 2019) to measure variations in thermal transmittance (U-value) following International Standard ISO 9869–1. The locations were first selected by preferring northerly orientation, avoiding facades exposed to solar radiation, and avoiding heat sources. Paired heat flux plates were used to observe the difference between what was observed to be “good” and “poor” areas of building fabric as assessed through the thermal

4.1: UK case study 51

Figure 4.2  Heat flux measurement location on stairway wall (a) with thermal image (b).

imaging assessment. For each surface area selected for heat flux measurement, the “good” refers to the warmer surface temperature that covers most of the surface as seen through thermal imaging (Figure 4.2). “Poor” refers to areas that stand out with notably lower surface temperatures. These are areas of thermal bypass and the results of expected thermal bridges. Figure 4.2 shows the heat flux measurement location on stairway wall in ZP1 as dictated by thermography. AR02 is the “good” spot, and AR01 is the “poor” spot. The process of quantifying the thermal transmittance involved data logging of the temperature on each side of the fabric element and the heat flow through the heat flux sensors. Air temperatures were measured in the respective rooms and outside the fabric as near as possible to the same part of the fabric. U-value W/(m2·K) of a wall is heat flux (in W/m2) divided by temperature difference (K). This is calculated from the average value of heat flux divided by the average temperature difference. Because temperatures and heat flow vary during the test, average values of each parameter need to be taken over an extended test period. Pre-occupancy test limitations: • ZP2 had inoperable heating, thereby limiting the temperature difference between the interior and the exterior. • Given time and material limitations, the project was limited to three paired simultaneous heat flux measurements. For this reason, wall measurements were prioritized in the two dwelling types with operable heating, that is, ZP1 and ZP3. The roof measurement was done on ZP2. • The “worst” areas were sought out for taking heat flux measurements; therefore, the thermal transmittance results from the assessment may be higher than the thermal transmittance of each element in the dwellings overall. 3.3.2 Energy and environmental data collection

To evaluate the key performance indicators of the ZERO-PLUS dwellings, data loggers were deployed inside and outside the dwellings. Each main room received

52  Rajat Gupta, Matt Gregg, and Owen Daggett both ORSIS and Hobos for temperature, and RH measurements and ORSIS and TinyTag to measure CO2 concentrations. HIVE smart thermostats were installed to serve each floor and were centrally located for this purpose. The HIVE thermostats provided data on temperature at the location, set point settings, and on/off status. In summary, the following parameters were measured on-site: Energy consumption at the dwelling level; location: energy monitoring equipment located in storage closet under stairs in each dwelling: • Total electricity consumption (measured in by both ORSIS loggers and the Tesla battery) • Lighting electricity consumption (ORSIS – outlet-powered, transmitted to WiFi) • Fan electricity consumption (ORSIS) • Space heating (ORSIS) • Domestic hot water (ORSIS) Energy generation/management at the dwelling level; location: batteries located under balcony of ZP1 and ZP2 and in garage of ZP3: • Total PV generation (Tesla – hardwired transmits to WiFi, Tesla app data access) • Battery charging/discharging (Tesla) Indoor environment (all parameters measured in living room and all bedrooms): • Temperature (ORSIS, HIVE, Hobo – battery-powered; I-button – batterypowered) • Relative humidity (RH) (ORSIS, Hobo) • CO2 concentrations (ORSIS, TinyTag – outlet-powered logger) • Window opening (Hobo) • Thermostat set point/heating on/off (HIVE) Outdoor environment (Davis Instruments); location: energy center (80–100 m away from dwellings): • Temperature • Humidity • Wind speed • Wind direction • Rainfall • Solar radiation Monitoring and analysis of in-use data began October 2019 and ended August 2020. There were occasional data gaps in the logged data; however, none lasted for significant spans, with the exception of heating in ZP1 (no heating data collected for entire study). ZP2 was not occupied until the end of January 2020.

4.1: UK case study 53 3.3.3 POE questionnaires

Two seasonal post-occupancy evaluation (POE) questionnaires and right-here-rightnow thermal comfort (TC) surveys were performed in the dwellings. These were for winter 2020 and summer 2020 assessments. The winter 2020 questionnaires were performed in person in February. After this, as COVID lockdowns restricted access to the homes in the summer, the summer questionnaires were entered into Google Form and sent via email at the end of July. The POE questionnaire covered demographic questions (e.g., gender, age, country of origin); symptoms of sick building syndrome (SBS); perception of ventilation, temperature, noise, lighting, and odors; and means of control for thermal comfort. The thermal comfort survey asked about the occupant’s feeling of comfort, comfort preference, activity, clothing, and the researcher took temperature and RH measurements on-site. 4 Design Advanced insulation, biPV, CHP/PV, Wind/PV, and BEMS were all tested individually for suitability and viability in the climate, the design of the development, and the local regulations. At the early stage, advanced HVAC and oil storage were precluded from the analysis as they were not considered appropriate for the UK climate and infrastructure. At the completion of the modeling and simulation phase of the project, CHP/PV and biPV were also excluded. CHP/PV was not considered fit for the UK climate based on modeling results and recommendation from the technology producer. BiPV was found in the modeling to increase the thermal conductivity of the element in which it was placed, creating a net loss, and therefore not appropriate. Though biPV could have been used as an entry canopy element or integrated at the community level, the cost of biPV was also considered a hindering factor. During the modeling and simulation stage, advanced insulation, BEMS, and Wind/PV were considered technically beneficial to the project. During the cost optimization stage of the project, the ZERO-PLUS-selected brand of advanced insulation was excluded for the following reasons: 1. The thermal conductivity of the insulation was equivalent to the standard insulation being used for the baseline Derwenthrope dwellings. 2. Following the 2017 Grenfell Tower fire and subsequent casualties in the UK, there was an increased level of due diligence of product certification. The critical issue with the ZP-specified brand of insulation was that it was not certified to the British Board of Agreement (BBA) standards, meaning, that it could not be installed in the UK. 3. Subsequent attempts to substitute the ZP-specified insulation with a BBAcertified product failed due to high costs associated with the products. In the end, no improvement to the fabric was approved; therefore, the insulation properties of the ZP dwellings matched the baseline dwelling, that is, what would have been built originally in the absence of the ZP intervention. The Wind/PV product was also excluded due to final cost, planning constraints, and inability to arrive at an agreement regarding installation responsibilities, warranties, and service and

54  Rajat Gupta, Matt Gregg, and Owen Daggett maintenance obligations. As a result, the only remaining ZP project partner technology installed in the dwellings was BEMS. To meet the KPIs, standard PV panels were installed on the roof of each dwelling, and batteries were installed to improve self-consumption of generated electricity. As the ZERO-PLUS project has a settlement-scale focus, the initial plan for installation of the PV was to install the entire array on the roof of the energy center of the development. Batteries would also be installed in the energy center and serve the dwellings in aggregate. The greatest weakness in this plan, which ultimately caused the solution to be impracticable, was that the roof of the energy center could not structurally hold the entire array. Altering the structure of the roof to support the array would have caused the ZERO-PLUS settlement cost-savings KPI to fail. In contrast, the typical “non-settlement-minded” solution would have been to install an equivalent capacity, that is, enough to generate about 17 kWh of electricity per year per dwelling on the roof of each of the three dwellings to meet the ZP KPI. As noted, there would have been a great sacrifice to efficiency, as northeastfacing roofs of the dwellings would have been used. The final solution was to use the south-facing roofs of the ZP dwellings and the south-facing roof of one additional dwelling to avoid sacrificing efficiency and to capture a “settlement-level” approach. The BEMS technology was HIVE, a smart thermostat and home system. HIVE includes a wireless thermostat control device that communicates with a hub that is connected to the home’s broadband router, and the receiver, which allows the thermostat to communicate with the boiler. The HIVE smart thermostat element can be controlled using voice commands or smart device applications. The thermostat can also be controlled like a traditional thermostat, for example, via direct device control and scheduling. A key feature is the ability to remotely control a home’s heating while away from the home. The HIVE home energy management system, in theory, improves the conservation of heat in the dwellings by allowing the user to control the magnitude and timing of heat consumption at a fine detail. 5 Delivery All three dwellings were constructed as standard Derwenthorpe dwellings, with the exception of the BEMS integration, PV installation on the roof, battery integration to the electrical system, and monitoring equipment. 5.1  Pre-occupancy testing results

All three dwellings were found to have better AP results than the design target (4 m3/(h·m2) @ 50 Pa) when they were first tested upon completion for building regulation compliance: ZP1, 3.9; ZP2, 4.0; and ZP3, 2.8 m3/(h·m2) @ 50 Pa. The latter tests (ZP1, 5.4; ZP2, 5.4; and ZP3, 7.5 m3/(h·m2) @ 50 Pa), however, showed that none of the three dwellings met the design target, although all dwellings remained below the UK Building Regulations requirement of 10 m3/(h·m2) @ 50 Pa. ZP3 had deteriorated most significantly, and it was noted that there were

4.1: UK case study 55 holes in the kitchen wall where waste pipes had been fitted and the gaps around the pipes were not sealed properly. Other areas that had deteriorated included holes cut on the first floor, presumably to trace pipes or cables in the void and not properly filled, and cracks at the edges of the stairs and under the skirtings. These anomalies were re-confirmed in the thermal imaging survey under depressurization. According to the developer, some work had been done on the properties to fix defects between the first and second tests. The thermal imaging survey of the dwellings showed air leakage pathways around openings and penetrations. Most surfaces were found to have a low thermal index, which generally equates to higher U-values. In ZP1, the most common anomalous areas were around skirting boards and at the junctions between the ceilings and walls. ZP2 showed similar signs of air leakage throughout the property, as well as air leakage around the openable elements, especially around doors and windows. ZP3 also showed similar signs of air leakage that was observed within the other two properties. This was mainly seen at the junctions between the ceiling and the wall and around external doors. Overall heat flux measurements showed poor thermal quality of the walls and roof section that were measured. Whereas “good” and “poor” quality sections were measured, even the “good” quality sections did not meet the design U-values. The measured values of thermal transmittance for the walls of the dwellings were found to be significantly higher than design values. In fact, the measured external wall U-values (ZP1 good, 0.47/poor, 1.39 W/(m2·K); ZP3 good, 0.56/poor, 1.95 W/(m2·K)) do not meet UK Building Regulations limiting fabric parameters (0.30 W/(m2·K)). The measured U-value for the roof/ceiling was 0.19 W/(m2·K) in the “good” area, which is close to the design value, but the “poor” area corresponding to a roof joist was 1.28 W/(m2·K), which is eight times the design value (0.16 W/(m2·K)). Design U-values are discussed in more detail in Part 2. 5.2  Technology specifications

To meet ZERO-PLUS targets, the final technologies selected were BEMS, PV, and battery storage. The HIVE active heating and smart home system was installed to serve as an energy management tool for the occupants of the dwellings. The HIVE system included in each dwelling: • • • • •

Smart thermostats (2) (separate ground-floor and first-floor control) Smart light bulbs (3) Plug load monitor (2) Window/door sensors (3) Occupancy sensor (1)

To meet the energy generation requirements of the ZP project, a large PV array was spread across four dwellings, three neighboring (two adjoining) and one

56  Rajat Gupta, Matt Gregg, and Owen Daggett located a couple of streets away, all with southwest-facing roofs. Each dwelling features a 14-panel array of 300 W panels at a 50° tilt, each generating 4.34 kW. This provided a settlement approach as opposed to forcing the 15,000 kWh generation capacity needed onto the three ZP dwellings, which would reduce efficiency and increase costs. At 17.36 kWp, the PV produces an estimated 15,160 kWh of electricity annually. The PV generation is supplied to the dwellings individually, but total generation is netted to the three ZERO-PLUS dwellings to achieve the ZERO-PLUS KPIs. The three ZP dwellings also have batteries to store and displace solar peak energy to peak consumption times. The resulting design allows for separated generation and storage, with a “net” calculation between generation and storage to theoretically balance the system. To complement the generation requirements, a 13.5 kWh Tesla Powerwall II battery was installed for each ZP dwelling. The batteries automatically drive the smart consumption of PV and battery power. PV to home connection is prioritized, and when the home does not require power from the PV, it is routed to the battery. If the home does not require power and the battery is full, the PV generation is fed into the grid. When PV is not generating, the home uses battery power before the grid. 6 Operation Roughly three months after completion of construction, the dwellings were occupied between August 2019 and February 2020. Table 4.1 shows occupancy details in the three ZP dwellings. Most energy is consumed in the evening for all three dwellings.

Table 4.1  ZERO-PLUS dwelling occupancy details ZP1

ZP2

ZP3

First full month in dwelling No. of occupants Household Pets Declared occupancy Occupancy pattern (most energyintensive hours)

August 2019

February 2020

September 2019

3 1 adult, 2 children 0 16:00–24:00 6:00 a.m.–8:00 a.m., 6:00 p.m.–10:00 p.m.

3 2 adults, 1 child 0 24 hours 6:00 a.m.–8:00 a.m., 7:00 p.m.–11:00 p.m.

4 2 adults, 2 children 2 small dogs and fish 24 hours 5:00 a.m.–9:00 a.m., 6:00 p.m.–10:00 p.m.

Mean heating set point* Period heated

29–30°C

23–24°C

17–18°C

October 1–May 18

January (move-in date) 23–April 5

September 22– April 5

* Heating set point does not indicate actual temperature averages.

4.1: UK case study 57 6.1  Energy consumption and generation analysis 6.1.1 Overall energy consumption

The in-use results for each dwelling (based on one year of monitored data: September 2019–August 2020) show that the actual total in-use consumption of the dwellings is lower than the as-designed expectation (Figure 4.3). Space heating consumption in ZP1 had to be 100% estimated as the space heating monitoring equipment failed. Space heating in ZP2 was 75% estimated as the occupants did not occupy the dwelling until the end of January. The as-built model was based on findings from the pre-occupancy evaluation. At that stage, the as-designed models were revised to match the air permeability and heat flux measurements. PV generation as a total covers all electricity consumption in the dwellings. In-depth assessment of self-consumption and export is detailed later. Overall, the project as a settlement successfully achieved the project KPIs. Final renewable generation was 51 kWh/m2/year, and final net-regulated energy consumption was 8 kWh/m2/year (Figure 4.4). The settlement, however, did not achieve net-zero, net-regulated status. It is important to clarify here that an additional PV array was installed on a nearby dwelling to achieve the total 51 kWh/m2 generation. This was done to achieve the “settlement” target without sacrificing efficiency, as PV would have had to be installed on the north-facing roof to fit the entire required capacity on the ZP dwellings. Therefore, the homes, as they stand alone, are not net-zero. On a monthly basis, some key patterns are notable among the dwellings. Space heating consumption peaks in December, and PV generation peaks in May. December also marks the month with the lowest PV generation. Across the three dwellings, annually, space heating was the largest use of total energy (between 50 and 58% in winter), however, less than the typical UK

Figure 4.3  ZP modeled and actual energy consumption and generation results.

58  Rajat Gupta, Matt Gregg, and Owen Daggett

Figure 4.4  ZP modeled and actual energy consumption against design target.

dwelling (Palmer & Cooper, 2013). ZP3 had the largest percentage of appliance use in all seasons; in winter, the proportion of appliance use was twice that of the other dwellings. With respect to other end uses, annual domestic hot water (DHW) consumption was higher than the UK average (18%), and annual lighting proportion was lower than the UK average (3%) (Palmer & Cooper, 2013). 6.1.2 Energy production

The location, orientation, and tilt of the PV array, combined with the seasonal variation of the location, provide more generation in the spring than in summer. The generation in autumn and winter is almost identical. Figure 4.5 shows the settlementlevel electricity balance. Instantaneous self-consumption of PV represents 27% of total generation, self-consumption through the battery represents an additional 44%, and a remaining 29% is exported to the grid. There is a clear combined peak load for all three dwellings from 16:00 to 17:00 averaged over the year. The PV instantaneous self-consumption reduced this load by 48%; however, the batteries helped reduce the overall peak load by 90% overall. On a seasonal basis, most direct electricity from the grid is consumed in autumn and winter. Overall PV production is 20% higher in spring, but instant self-consumption was 4% higher in summer. The installed PV arrays generate between 40 and 50% of each dwelling’s total energy consumption. This is between 55 and 66% of each dwelling’s total regulated energy consumption. However, as most of the total energy consumption in the dwellings is from gas use, the batteries have proven to be exceptionally helpful in reducing actual electricity consumption in the dwellings by spreading out the ability to self-consume. At an individual-dwelling level, the instantaneous self-consumption of PV ranged from 22 to 35% (total with battery ranged from 57 to 72%). Summary of energy management: • ZP1 did not charge the battery from the grid. Battery discharge was greatest from 16:00 to 21:00.

4.1: UK case study 59

Figure 4.5  Settlement-level electricity balance.

• ZP2 did charge the battery from the grid. This occurred overnight and was greatest around midnight. Battery discharge was greatest from 16:00 to 17:00 and 20:00 to 21:00, with a dip between these two periods. • ZP3 depended on significant battery charging from the grid. This occurred overnight and was greatest around 01:00. The battery charging from the grid was greater than the battery charging from PV. However, this charging from the grid did not stand in the way of the charging from PV, as there was a notable morning discharging (06:30–09:00) for consumption (as compared to the other dwellings). Battery discharge was greatest from 16:00 to 17:00. 6.2  Indoor environment analysis 6.2.1 Seasonal temperature, relative humidity, and CO2 concentrations

Winter averages in the dwellings ranged from 17°C in ZP3 to 22°C in ZP2. ZP2 kept temperature on the high end of what is recommended, and ZP1 retained a reasonable range as per recommendations. In contrast, ZP3 consistently kept the dwelling at temperatures that would be considered cold and borderline potentially harmful for vulnerable occupants (Wookey et al., 2014) in the winter. The following summarizes indoor temperature and RH-related findings: ZP1 • Most temperatures on the ground floor in the winter were within recommended range. However, ZP1 considered the temperature in winter to be “poor.” ZP1 did, however, have the largest range between max. and min. • Both the ground and first floors were experiencing higher than recommended temperatures in the summer, with potential overheating. Highest temperatures in summer among the dwellings.

60  Rajat Gupta, Matt Gregg, and Owen Daggett ZP2 • Most temperatures on the ground floor in the winter were within recommended range; however, the first floor appeared to be heated a little higher than necessary. • Maintained a constant average of 22–23°C throughout the year. Highest temperatures in winter among the dwellings. • The first floor was experiencing most temperature much higher than recommended temperatures in the summer, with potential overheating. ZP3 • Most temperatures on the ground floor and first floor in the winter were below the recommended range. Lowest temperature in winter among the dwellings. • The occupants were young, but there may be risk of being too cold, as a significant amount of readings are below 15°C. • Both the ground and first floors were experiencing higher than recommended temperatures in the summer, with potential overheating. As with the other dwellings, this is most notable on the first floor. In winter, ZP3 has higher levels of RH than the other dwellings (even higher in the bedroom). This is likely a result of window opening behavior. In the summer, RH is well within recommended range for the dwellings. All dwellings in summer averaged 51% RH in the living rooms and 53–55% RH in the bedrooms. Overall, the median CO2 concentrations throughout the year of all ZP dwellings were within the range of 600–800 ppm in the living rooms and 650–800 ppm in the bedrooms. Summer tended to have lower readings overall, especially in the living rooms, likely due to more ventilation, not only due to greater frequency, but also because of larger openings, that is, garden doors. ZP3 had much higher maximum readings overall. Among the living rooms in all seasons, ZP1 had lower median and maxima. In the bedrooms, however, ZP1 tended to have higher maximum concentrations. 6.2.2 Indoor environment control via BEMS

On average in ZP1, peak heating happened between 6:00 and 9:00, with another slow and steady hump from 9:00 to 23:00, with the evening peak around 17:00 to 18:00. December is the month with the most heating use. Most months in the heating season follow a tight hourly average from around 18 to 20°C. In ZP1, the heating system temperature setting for the most part was used as an on/off switch. Heating was set to 31 or 32 (maximum temperature on thermostat) to begin heating and turned off when desired comfort was reached. On average, in ZP2, peak heating happens between 6:00 and 8:00 in the morning and 15:00 to 21:00 in the evening. Most of the time, the main set point was around 23°C; this aligns well with the average evening peak temperature in the dwelling.

4.1: UK case study 61 In ZP3, there is also very little evidence of a clear peak heating time in the dwelling. In the months of October 2019–January 2020, the heating set point and on/off schedule were sporadic; however, from February to April 2020, it appears that the occupants adopted a heating behavior of maintaining the temperature at a steady average set point around 16°C. ZP3 was significantly underheating as compared to ZP1 and ZP2. 6.3  Occupant survey

For each survey period, four responses were returned (one in ZP1, one in ZP2, and two in ZP3). All respondents were fairly young, with young families, native to England, and typically spending most time at home. Their self-reported health condition is nearly equally split between “usually healthy” and “chronic condition.” In the winter period, perception of temperature, ventilation, noise, lighting, and odors was mostly “very good,” with some “good” and two “poor” votes. The “poor” votes were with respect to temperature in ZP1 and noise in ZP3. The data demonstrated through standards that the bedrooms were too warm in the winter for most of the time in ZP2; however, the occupant considered the temperature in winter to be “good” and did not prefer the home to be warmer or cooler. In the summer period, ZP3 saw some improvement in their perception of the indoor environment, ZP1 remained the same, and ZP2 considered lighting and odors to be “good” as opposed to “very good” in the winter. In the winter period, all but ZP2 reported that they open windows to control the thermal environment. Review of window opening behavior in the winter confirms that ZP2 did not open living room windows and bedroom windows were opened minimally. Furthermore, window opening in the summer was also minimal but necessary for ventilation. In the summer, all dwellings reported opening windows and doors to control the thermal environment. At the same time, all respondents but one in ZP3 stated that the dwelling was generally “too warm” in the summer and difficult to cool down. The perception of the impact of opening the windows and doors to cool down the space varied between respondents widely. Overall, the ZP dwellings rated their ease of control and effectiveness of the systems on the higher end of the range (mean control = 6, and effectiveness = 6.5). ZP1, for example, considered the response to both questions to be very easy/effective; they also counterintuitively considered the indoor temperature in winter to be poor. They also noted that they use the radiator valves to control room temperatures, which would make sense, given their set point control pattern outlined in the earlier section on controlling the indoor environment. 7 Concluding discussion This chapter has demonstrated the approach and results from the design, simulation, and performance evaluation of ultra-low-energy dwellings in the UK. As the UK is striving to be a net-zero economy by 2050 through such measures as broad electrification of the residential sector, studies like this demonstrating actual

62  Rajat Gupta, Matt Gregg, and Owen Daggett performance are important in revealing the drawbacks and potential. The dwellings’ design and implementation provide a potential path forward toward the UK’s carbon reduction targets; however, more would need to be done at the dwellingand settlement-level to satisfactorily meet the UK’s net-zero carbon target by 2050. Unfortunately, in the case of the ZP dwellings, the large PV arrays installed on the homes and the selected fabric solution were not enough to achieve net zero. Though the dwellings were designed to achieve a standard better than current building regulations, there was a missed opportunity to design and build more-efficient dwellings (e.g., greater fabric efficiency, including lower insulation conductivity, tighter fabric, coupled with MVHR). In addition, pre-occupancy evaluation revealed notable flaws which could have led to less-efficient fabric than as designed. These were higher air permeability rates and higher measured U-values than as designed. With respect to roof space and the PV array, a few more panels could have been installed on ZP3, but the roof of ZP1 and ZP2 could not have supported any more. If additional PV were the solution, a local community installation would have been necessary to provide the additional PV generation needed. Given ZP1 dwelling’s current built characteristics and occupancy, an additional array of the same size, tilt, and azimuth as the current array would be required to achieve net zero. The other dwellings would require an even larger array. However, as the development on the whole includes around 500 dwellings, based on the performance in these three dwellings, a community installation in addition to panels on every roof could not provide the demand needed to achieve net zero. An important recommendation coming out of this experience is the need for better building fabric standards and wide support for the residential sector to build and retrofit to meet better fabric standards that precede renewable solutions. At this stage, there is little to no guidance and support for the able-to-pay portion of the sector in the UK. Despite the drawbacks, the combination of electricity generation and smart battery storage is shown to be a flexible and resilient solution. The case studies have demonstrated that batteries would be greatly beneficial to increasing selfconsumption of renewables. The results of the dwellings have shown that batteries are “smart” devices that are helpful in shifting the renewable energy or overnight (off-peak) grid charging to peak demand times in dwellings. As the batteries were able to double the SC of the PV systems and the combined PV and battery combinations were able to reduce average peak load by a significant amount, this technology will undoubtedly help the UK government meet its goals to develop a smart energy system and reduce peak electricity demand pressure on the electricity grid under aggressive electrification of the residential sector. The indoor conditions varied significantly between the dwellings that were constructed together in location and time with the same specifications. It is evident that heating preferences and expectations can overtake the capabilities of a smart thermostat. This reinforces the importance of understanding, designing for, and addressing occupant behavior; occupant behavior has a significant impact on how a dwelling is operated. In light of the wide variation in measured indoor temperature across the dwellings, it is vital that energy models consider a range of heating preferences to avoid a large gap between expectation and reality.

4.1: UK case study 63 The BEMS were a difficult technology from which to capture the benefit. It would appear that factors such as resident expectations, preferences, and understanding of heating controls are more consequential than simply installing a smart thermostat. Without appropriate training, overarching preferences and behaviors of the occupants can be carried from one type of thermostat (standard, programmable) to the next, negating any special or “smart” features. For any upcoming smart heating technology rollouts, it is vital to have training of residents on use of the system and troubleshooting should the control not yield the expected result. The different needs and requirements of the occupants need to be addressed, and the solution will need to be highly customizable to the user. This will be an important step in achieving the intended energy savings of these smart controls that are expected to become widespread in a smarter energy system. References BEIS. (2019). UK Becomes First Major Economy to Pass Net Zero Emissions Law. Retrieved March 23, 2020, from www.gov.uk/government/news/uk-becomes-first-majoreconomy-to-pass-net-zero-emissions-law CCC. (2019). UK Housing: Fit for the Future? London: Committee on Climate Change. DCLG. (2006). Code for sustainable homes: A step-change in sustainable home building practice. In Department for Communities and Local Government (Ed.). London: Communities and Local Government Publications. DCLG. (2008). Code for Sustainable Homes – Technical Guide. London: Department for Communities and Local Government. Palmer, J., & Cooper, I. (2013). United Kingdom housing energy fact file. In DECC (Ed.). London: Department of Energy & Climate Change (DECC). Quilgars, D. J., Dyke, A., Wallace, A., & West, S. E. (2019). Making a Sustainable Community: Derwenthorpe, York, 2012–2018. York: University of York. UK Government. (2019). The Climate Change Act 2008 (2050 Target Amendment) Order 2019. London: Legislation.gov.uk. Wookey, R., Bone, A., Carmichael, C., & Crossley, A. (2014). Minimum Home Temperature Thresholds for Health in Winter – A Systematic Literature Review. London: Public Health England.

4

Part 2: Energy modeling of positive-energy dwellings Rajat Gupta and Matt Gregg

1 Introduction This chapter is the second in a two-part series on the design and evaluation of the UK ZERO-PLUS (ZP) dwellings. This chapter describes the modeling and simulation of the case study dwellings in the UK framed within the larger context of the methodologies used in the project to refine the design to optimally meet the project key performance indicators. In this chapter, the following section describes the methodological approach to each phase of the project, where modeling and simulation were applied. Section 3 provides results from each stage, and Section 4 closes the chapter with a conclusion. 2 Methodology Within the four phases of the project, modeling and simulation were applied at three key stages, resulting in six models: 1. Design development (December 2015–December 2017) a. b. c. d.

Baseline model Typical reference case model UK Building Regulations reference case model As-designed model

2. Post-construction/pre-occupancy evaluation (April–September 2019) a. As-built model 3. Building performance evaluation (BPE) (October 2019–August 2020) a. In-use model 2.1   Modeling and simulation software

Modeling and simulation were performed using Integrated Environmental Solutions Virtual Environment (IES VE) suite. ModelIT was used for modeling the external physical characteristics of the dwellings, and Apache for setting thermal DOI: 10.1201/9781003267171-5

4.2: Energy modeling of positive-energy dwellings 65 parameters and running simulations. The IES VE thermal calculation and dynamic simulation software was selected as it is an approved industry standard, audited by the Chartered Institution of Building Services Engineers and the United Kingdom Accreditation Service, as well as being an accredited software for producing energy performance certificates by the Building Research Establishment (BRE). 2.2  Design development

The first modeling and simulation phase set out to model the baseline design, reference cases, and the model of the dwellings as they were expected to be built. 1. Baseline model. Model of the dwelling as designed for the Derwenthorpe development exclusive of zero-energy design influence. 2. Reference cases. Reverse modeling of the baseline to establish reference cases: a. Typical reference case, that is, consumption of typical existing dwelling in England. b. UK building regulations reference case: applied building regulations to the model. 3. As-designed model. The modeling of all technological advancements planned for the model. This step included testing and evaluation of the impact of each ZP technology individually and in combination. This model was to stand as the representation of the expected performance of the final design to be built. The overall objective of the design development phase was to revise the design of the original dwellings to achieve energy consumption and generation key performance indicators (KPIs) of the ZERO-PLUS project. These are described in Chapter 4 Part 1. 2.2.1 Data request

The design process began with an extensive request for data from the developer, architects, and technology providers. The request of almost 200 points of data covered an array of details that would be required to complete a dynamic thermal model for each dwelling, for example, plans, specifications for insulation, design air permeability (AP), etc. The data queries were divided into sections related to phases of modeling. These were: • Base model construction (gathered from construction drawings) – floor area, window sizes, door sizes, ceiling heights, etc. • Fabric constructions (gathered from specifications, project data sheets) – material thicknesses, conductivities, window fill gas, window g-values, etc. • Thermal templates for rooms (gathered from Standard Assessment Procedure (SAP) worksheets, design intent declarations) – domestic hot water (DHW) consumption, lighting wattage, number of occupants, infiltration rates, etc.

66  Rajat Gupta and Matt Gregg • Use profiles (design intent, standard assumptions) – heating profile, auxiliary ventilation profile, window opening profile, etc. • Systems profiles (gathered from product data sheets) – main HVAC system type, fuel, DHW tank insulation thickness, PV array type, CHP heat output, rated wind power, etc. • Macro airflow process (gathered from construction drawings) – exposure, openable area, open angle, length and width of openings. The following section lists a few of these parameters used in the project. 2.2.2 Constructing the baseline model

After all requested data were gathered, the models were built using provided plans and specifications. Not all data points were provided by the design team; in this case, standard assumptions had to be made. Hourly weather data used were typical meteorological year data (TMY) for Leeds, England, located 38 km from the site. Table 4.2 shows modeling parameters in the ZP project as an example. Table 4.2  Modeling parameters Modeling parameter

Details ZP1

ZP2

ZP3

Total floor area (m2) Envelope area No. of bedrooms SAP rating (designed)

84.4 245.8 2 B – 82

84.4 245.8 2 B – 82

129.6 321.1 3 + study B – 83

Modeling parameter

Type

External wall U-value

Filled cavity wall 0.17 W/(m2.K) From out to in: 102.5 mm brick, cavity, 100 mm insulation at 0.022 W/(m·K), 102.5 mm concrete block, 12 mm plasterboard Glass mineral wool insulation 0.23 W/(m2.K) Pitched w/rigid polyisocyanurate 0.16 W/(m2.K) (PIR) insulation core faced with an aluminum foil composite From out to in: 12 mm roofing tile, 12.5 mm sheathing, roof void, 130 mm insulation at 0.023 W/(m·K), 12 mm plasterboard (timber-framed) Rigid PIR 0.14 W/(m2.K) From out to in: ground, 100 mm gravel, 200 mm insulation at 0.035 W/(m·K), 100 mm concrete, 12 mm carpet Double glazed in uPVC frame 1.3 W/(m2.K) 0.4 4 m3/(h.m2)@50pa Gas boiler–district heat MEV: extract only: kitchen 60 l/s; bathrooms 15 l/s (HM Government, 2010)

Party wall Roof U-value

Ground floor U-value Window U-value Window g-value Design AP Heating Mechanical ventilation

Final design parameter

4.2: Energy modeling of positive-energy dwellings 67 Modeling parameter

Parameters applicable to all models

Occupancy profiles

Operational profiles developed by the UK National Calculation Methodology (NCM) and provided with the IES VE software Morning: 6:00–10:00 (with maximum presence at 7:00– 9:00); evening: 18:00–23:00 (with maximum presence at 19:00–22:00) 22:00–9:00 (with maximum presence at 24:00–7:00)

Living room occupancy pattern Bedroom occupancy pattern Heating set point Heating schedule ( BRE, 2014) Hot water consumption Internal gains Living room internal gains Kitchen internal gains Bathroom internal gains

Living: 21°C; all others: 18°C (BRE, 2014) October 1–May 31 Weekday: 07:00–9:00 and 16:00–23:00 Weekend and holidays: 07:00–23:00 Average consumption of 3,000 kWh/year (Palmer & Cooper, 2013) “Light” occupancy profile provided in the BRE Technical Note 90/2: standard dwellings for modeling (Allen & Pinney, 1990). TV, TV box, laptop, router, game system/DVD player, lighting Dishwasher, toaster, kettle, microwave, oven, hob, fridge, hot water gains, lighting Hot water gains, bathroom lighting

2.2.3 Reference cases

There were two reference cases for comparison. These were: 1. Ref. 1: typical UK dwelling from most common typology and age group (semidetached, 1945–1964 (DCLG, 2015)). 2. Ref. 2: dwelling constructed to contemporaneous UK Building Regulations relevant to the development (HM Government, 2010). Ref. 2 is also useful for cost analysis described later. Typical reference case (Ref. 1) construction details were obtained from the Tabula and Episcope Building Typology Brochure (2014). In addition, however, recent retrofit data was used to refine the Ref. 1 case (DCLG, 2015): • 68% of cavity wall dwellings were estimated to have cavity wall insulation by 2013. • 80% of all dwellings and 91% of housing association homes were estimated to have more than half of windows double-glazed by 2013. • 56% of dwellings had 150 mm or more of loft insulation by 2013. Examples of specification differences were: • Wall U-value: Ref. 1: 0.6 W/(m2.K); Ref. 2: 0.26 W/(m2.K) • Roof U-value: Ref. 1: 0.24 W/(m2.K); Ref. 2: 0.2 W/(m2.K)

68  Rajat Gupta and Matt Gregg • Window U-value: Ref. 1: 2.2 W/(m2.K); Ref. 2: 1.6 W/(m2.K) • AP: Ref. 1: 2 air changes per hour; Ref. 2: 8 m3/(h.m2)@50pa 2.2.4 As-designed model

The purpose of the as-designed model was to predict the performance of the improved design. The advanced technologies considered to be relevant and tested were: • Advanced insulation. Modeled in IES VE: additional 100 mm of insulation in external walls, resulting in 0.11 W/(m2.K); additional 110 mm of insulation in roof, resulting in 0.10 W/(m2.K). • biPV. Modeled in IES VE: installed in south roof face; low-e triple glazing with dye-sensitized solar cells integrated. • CHP/PV. Modeled in tech. providers software: solar and thermal power are calculated from solar azimuth, solar elevation (altitude), global radiation, and diffuse radiation. • Wind/PV. Modeled in tech. providers software: wind and solar power are calculated from wind direction, wind speed, global radiation, and solar altitude. • Building energy management system (BEMS). Smart home energy management. Some aspects of the technologies could be modeled in the dynamic simulation software (e.g., biPV); however, others required bespoke software developed by the technology providers (e.g., CHP/PV). Not all technologies introduced for the project were considered relevant to the UK climate. As explained in Chapter 4 Part 1, as a result of ZERO-PLUS team modeling, BEMS was the only ZP technology selected for the design; however, to meet the KPIs, a standard approach to PV installation was used. 2.2.5 Cost optimization refinement of the as-designed model

Three different variations on the ZP design were used to optimize the cost of improvement for the ZP design. These were: 1. Conventional building. The dwellings designed to meet current regulations – see model Ref. 2. 2. Zero-energy reference model. Dwellings designed to match as-designed model using conventional methods. 3. The as-designed model. Incorporating typical costs for acquisition, supply, and installation of the relevant technologies, the cost difference was calculated between the cost of the as-designed model and the zero-energy reference model. 2.3  Post-construction model calibration 2.3.1 As-built model

Following the pre-occupancy testing phase described in Chapter 4 Part 1, the asbuilt model was updated with measured data on U-values and AP and calibrated

4.2: Energy modeling of positive-energy dwellings 69 using hourly monitored temperature data in the unoccupied dwellings. To calibrate the model using actual pre-occupancy conditions and temperature data, the following steps were taken: • Actual weather data were imported. • All internal gains from occupant activity were removed from the model, that is, occupant body heat, appliance energy, DHW energy, and lighting energy. • Occupant window opening patterns were removed from the model. • Heating patterns were removed. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) validation indices method (ASHRAE, 2014) was used to model uncertainty in results. Two validation indices were used to quantify the model’s accuracy: normalized mean bias error (NMBE) and coefficient of variation of the root-mean-square Error (CV[RMSE]). When using hourly calibration data, NMBE should be at most 10%, and CV(RMSE) should be at most 30% (ASHRAE, 2002). 2.3.2 In-use model

After a year of building performance data collection, a final model calibration was performed. Data used for the final calibration included: • Actual weather data monitored via the weather station on-site. Where data was incomplete, online accessible local weather station data was used to fill in the gaps. • Occupancy patterns measured through activity on BEMS, number of people (POE survey). • Heating pattern and magnitude of control from BEMS. • Pre-occupancy fabric assessment/as-built calibration details for AP, external wall thermal transmittance, and roof thermal transmittance. • Measured indoor temperature data. • Measured space heating energy. Air permeability, thermal transmittance, occupancy pattern, occupancy count, heating pattern, and heating set point were updated in all models to align the simulation with reality. Again, the ASHRAE validation indices were used for accuracy. Where monthly calibration data are used (as was done for final calibration), the requirements for NMBE is 5% and for CV(RMSE) is 15%. 3 Results 3.1  Baseline and as-built results

In the modeling and simulation stage of the project, the baseline dwellings, that is, typical Derwenthorpe dwellings, were estimated to consume around 60% less

70  Rajat Gupta and Matt Gregg

Figure 4.6 ZP model simulation results: (g) indicates gas consumption, and (e) indicates electricity.

energy than the Ref. 1 dwellings and 33% less energy than the Ref. 2 dwellings. Figure 4.6 shows the simulation results for all four variations of the model. The ZERO-PLUS model, that is, the as-designed model, shows the simulated impact of BEMS and PV. 3.2  Cost optimization

The estimated costs for the ZP building were 17.8% less than those of the zeroenergy reference building, meeting the project KPI. The most significant difference came from using a settlement approach for PV installation as opposed to an individual-dwelling approach for PV installation. 3.3  As-built and in-use model

Following an increase in external wall U-value from 0.17 to 0.26 W/m2K and roof U-value from 0.16 to 0.19 W/m2K, the result of NMBE was 0.8%, and the result of CV(RMSE) was 5% for the as-built calibration. Using ZP1 as an example, following an increase in external wall U-value from 0.17 to 0.35 W/m2K, party wall U-value from 0.23 to 0.36 W/m2K, roof U-value from 0.16 to 0.19 W/m2K, and AP from 4.0 to 4.7 m3·h–1/m2 at 50 Pa, the result of NMBE was 1.6%, and the result of CV(RMSE) was 8.2%. 4 Concluding discussion The intent behind the presented methodological approach is to provide a useful process for baselining, improving a design, analyzing the magnitude of gap between

4.2: Energy modeling of positive-energy dwellings 71 as-designed and as-built, and analyzing the magnitude of gap between as-designed and in-use. Depending on targets of a jurisdiction, reference models can be used as a baseline reference from which to judge the improvement of a design to meet a specific low-carbon or net-zero related target. As shown, the reference model is also useful as baseline for cost-related optimization. There are several ways to calibrate a model based on building performance evaluation. Robust measurements of U-value and air permeability can be helpful in calibrating the model to show asbuilt conditions, thereby removing fabric-related unknowns from the model. This method of calibration can be helpful in attempting to isolate the magnitude of occupant behavioral influence on the performance of the dwelling. References Allen, E., & Pinney, A. (1990). Standard Dwellings for Modelling: Details of Dimensions, Construction and Occupancy Schedules. Garston: Building Environmental Performance Analysis Club. ASHRAE. (2002). ASHRAE guideline 14–2002: Measurement of energy and demand savings. In Measurement of Energy and Demand Savings. Atlanta, GA: ASHRAE. ASHRAE. (2014). ASHRAE guideline 14–2014: Measurement of energy, demand, and water savings. In Measurement of Energy, Demand, and Water Savings. Atlanta, GA: ASHRAE. BRE. (2014). The Government’s Standard Assessment Procedure for Energy Rating of Dwellings: 2012 Edition. Building Research Establishment. www.bre.co.uk/filelibrary/ SAP/2012/SAP-2012_9-92.pdf DCLG. (2015). English Housing Survey: Profile of English Housing: Annual Report on England’s Housing Stock, 2013. Department for Communities and Local Government. www.gov.uk/government/uploads/system/uploads/attachment_data/file/445370/EHS_ Profile_of_English_housing_2013.pdf HM Government. (2010). Approved document F 2010 edition with 2013 amendments. In Approved Document F: Ventilation (p. 63). Newcastle upon Tyne: NBS. Palmer, J., & Cooper, I. (2013). United Kingdom Housing Energy Fact File (13D/276). www.gov.uk/government/uploads/system/uploads/attachment_data/file/345141/uk_ housing_fact_file_2013.pdf Tabula & Episcope. (2014). Building Typology Brochure England September 2014. http:// episcope.eu/building‐typology/country/gb/

5

Part 1: Italian case study Gloria Pignatta

1 Introduction The EU H2020 ZERO-PLUS project (H2020 Project ZERO-PLUS, 2015) is aimed at the development of near-zero and positive-energy settlements that can contribute to meeting the European Union’s 2020 energy and environmental targets. The project aims to demonstrate the technical and economic feasibility of NZESs through the development of pilot projects in four European countries, each with its own specific climatic, technological, and regulatory conditions. The Italian case study is one of these pilot projects, and it aims to demonstrate the feasibility of the ZEROPLUS approach in a temperate Mediterranean climate (Mavrigiannaki, Gobakis, et al., 2021). The purpose of this chapter is to present and discuss the performance and impact of the ZERO-PLUS approach on the design, construction, commissioning, operation, and evaluation of single-family villas located close to the city of Bologna, in Italy. The energy efficiency, renewable energy generation, and carbon emissions of the Italian settlement are here assessed and presented together with the key design and technological solutions that contribute to the overall performance of the settlement. Valuable insights into the barriers and opportunities for the implementation of the NZES concept in Italy and in similar climatic conditions are also discussed. Additionally, Chapter 5 provides a comprehensive look at strategies for improving energy efficiency and mitigating microclimate issues, with Part 1 focusing on building-level strategies and Part 2 delving into the design and implementation of community-level strategies. 2

Overview of the Italian case study site and settlement

The Italian case study settlement is designed to showcase the potential of the ZERO-PLUS project framework in a real-world setting and enhance the microclimate, comfort, and energy efficiency throughout the site. It is composed of eight new residential buildings, including two highly energy-performing villas that represent the ZERO-PLUS single-family demonstration villas (Figure 5.1), where the ZERO-PLUS approach has been applied from the design to the occupancy phase. The settlement covers a total flat area of approximately 9,600 m2, excluding DOI: 10.1201/9781003267171-6

5.1: Italian case study 73

Figure 5.1 Location of the Italian case study site in Granarolo dell’Emilia (BO), Italy: plan view of the settlement (red rectangle) and the two ZERO-PLUS single-family demonstration villas (white rectangle).

public spaces, and the total area dedicated to the two demonstration case study villas and their lots is close to 2,760 m2. The area where the settlement is located is part of a residential development area located in Granarolo dell’Emilia (BO), in the Emilia-Romagna region of northern Italy. Granarolo dell’Emilia is a town with a population of over 12,000 residents, boasting a population density of 350 people per square kilometer. The surrounding area of the settlement is located near a public park and is abundant in social services, such as schools, government offices, shops, banks, and more, as well as being well-connected by public transportation. 2.1  Geographical location and climate

The case study settlement Granarolo dell’Emilia (44°33’15” N, 11°26’38” E), situated at an altitude of 28 m above sea level, boasts a temperate and Mediterranean local climate characterized by a maximum mean annual temperature of 25°C and minimum mean annual temperature of 3°C. It is classified as climatic zone E, or Cfa, according to the Köppen-Geiger international classification (Beck et al., 2018), with approximately 2,162 and 110 heating and cooling degree days, respectively. The hottest season extends from June to September, and July represents the hottest month of the summer period, with a maximum mean temperature of 31°C. On the contrary, January represents the coldest month, with a maximum mean temperature of 7°C. The annual global solar radiation on horizontal surface corresponds to 1,429 kWh/m2, and the annual precipitation to 214 mm. Table 5.1 reports the monthly climate data for Granarolo dell’Emilia (Climate & Weather, 2023).

74  Gloria Pignatta Table 5.1 Monthly data of average maximum temperature (Ta,max), mean temperature (Ta,ave), minimum temperature (Ta,min), relative humidity (RH,ave), and precipitations (Rain,ave) for Granarolo dell’Emilia Month

Ta,max (°C)

Ta,ave (°C)

Ta,min (°C)

RH,ave (%)

Rain,ave (mm)

Jan Feb Mar Apr May

7 10 15 19 24

3 5 10 14 19

0 1 5 8 13

84 77 70 70 66

8.1 11.1 16.5 34.4 27.1

Jun Jul Aug Sep

28 31 31 26

23 25 25 20

17 20 19 15

64 61 63 68

21.5 7.5 6.7 17.4

Oct Nov Dec Year

19 12 7 31

15 9 4 14

11 6 1 0

80 85 84 73

31.6 18.8 12.9 17.8

Source: Based on 1985–2015 weather reports (Climate & Weather, 2023).

2.2  Buildings description and occupant profiles

The building type of the ZERO-PLUS Italian demonstration buildings is a singlefamily detached villa, with a total floor area of approximately 250 m2. The villas have their own private entrance and garden that is well connected with the surrounding outdoor areas of the settlement. Each villa sits on its own plot of land of about 800 m2, and their entrances face the northwest side. The two ZERO-PLUS single-family demonstration villas, named Villa A (a ground-floor building) and Villa B (a two-story building), operate under the same environmental conditions; present similar modern architecture, technical design, and construction characteristics; and incorporate the latest advances in sustainability and energy efficiency (Figure 5.2). Table 5.2 provides an overview of the main characteristics of the two demo buildings. Both villas are made of reinforced concrete. They feature high-performance insulation and airtight construction, as well as advanced heating and cooling systems (i.e., similar HVAC systems) that minimize energy consumption and reduce carbon emissions. Villas A and B are also equipped with home energy management and load control systems by ABB for the same purpose. The use of renewable energy technologies, such as photovoltaic panels (PVs) for electricity generation and ABB energy storage, is also a key aspect of the design, further reducing the environmental impact of the buildings. Overall, these Italian single-family demonstration villas represent a perfect balance of modern design and cutting-edge technology, showcasing ZERO-PLUS building principles in their

5.1: Italian case study 75

Figure 5.2 Italian ZERO-PLUS single-family demonstration villas: (a) photo and groundfloor plan of Villa A, and (b) photo and ground-floor plan of Villa B.

construction. More information about the selected technologies and design phase are provided in Sections 2.3 and 3.1, respectively. These villas reflect a typical Italian residential scheme and are designed to accommodate a family of three to five people, with three bedrooms, two bathrooms, a living room, a kitchen, a hall, a utility room, and a personal garage. In particular, after the completion of the construction phase, an elderly couple moved into Villa A and a family made of two adult parents with two children moved into Villa B during the summer of 2018 and spring of 2019, respectively. While the elderly couple spent most of their time at home during the project, the other family frequently traveled and was often out of the house during the day, despite each member having different daily schedules. Table 5.3 provides a brief overview of the demographic and lifestyle characteristics of the two families living in the two demo villas.

76  Gloria Pignatta Table 5.2  Overview of the building as-built characteristics for the Italian case study Size and general information

Villa A

Villa B

Total floor area Net floor area Building orientation Number of stories Number of bedrooms Thermal properties U-value of walls U-value of roof U-value of floor Ug-value of windows Infiltration rate at 50 Pa Other parameters Shading Glazing

241 m2 118 m2 Northwest 1 3

259 m2 131 m2 Northwest 2 3

0.164 W/m2 K 0.117 W/m2 K 0.167 W/m2 K 0.600 W/m2 K 0.575 vol h-1

0.250 W/m2 K 0.117 W/m2 K 0.167 W/m2 K 0.600 W/m2 K 0.500 vol h-1

Manual blinds Manual blinds Triple glazing with laminated glazing 33.1 in the external (selective treatment) and in the internal panel (low emissivity) and internal glass of 4 mm. Two argon cameras of 12 mm thick outward and 20 mm inward.

Table 5.3  Occupant profile comparison for the two families living in the ZERO-PLUS villas Feature

Family A

Family B

Occupation

Retired

Income Family composition Daily routine

Moderate/high Elderly couple Spend most of their time at home, participate in leisure activities

Professionals, the parents; and students, the children Moderate/high Couple with 2 children Both parents work and travel Children attend school and afternoon activities out from home

2.3  Building-integrated technologies

The ZERO-PLUS building-integrated technologies selected for, and implemented in, the Italian villas are reported in Table 5.4 and can be categorized under three main categories: • Energy conservation strategies, consisting of the advanced Fibran insulation panel • Energy production technology from renewable energy sources, consisting of solar PV panels • Energy storage and energy management solutions, consisting of ABB storage system, ABB load control, and ABB home energy management system (HEMS) The Fibran insulation panel is a thermal insulation board made of extruded polystyrene (XPS) and presents high thermal insulating properties. Only Villa A was

5.1: Italian case study 77 Table 5.4  Building-integrated technologies selected for the Italian villas Technology

Villa A

Energy conservation strategies XPS Fibran insulation 220 mm in walls and 150 mm panel in roof and ground floor, producing energy savings for 1 kWh/m2 per year Energy production technologies Solar PV for building use 14 panels for total 4 kWp, producing about 19.5 kWh/m2 Solar PV for settlement use 6 panels for total 2 kWp, producing 4.7 kWh/m2 Energy storage systems and energy management solutions ABB REACT+ for energy 1 module of 4 kWh and storage 200 V Li-ion battery and 3.6 kW hybrid inverter ABB load control for 1 module contributing to the energy management energy conservation ABB HEMS 1 system contributing to the energy conservation

Villa B -

14 panels for total 4 kWp, producing about 19.5 kWh/m2 6 panels for total 2 kWp, producing 4.7 kWh/m2 1 module of 4 kWh and 200 V Li-ion battery and 3.6 kW hybrid inverter 1 module contributing to the energy conservation 1 system contributing to the energy conservation

equipped with the XPS Fibran insulation system, which was integrated into the walls and sloped roof. The sloped roof was insulated with a thickness of 7 + 7.5 cm, while the ground floor and exterior walls were insulated with 10 + 5 cm and 22 cm, respectively. The other villa was equipped with Stiferite thermal insulation panels, as requested by the owner. Forty polycrystalline photovoltaic panels are utilized for energy generation. Each villa is equipped with 14 PV panels installed on the roof, with a total capacity of 8 kWp (kilowatts peak), producing approximately 39 kWh/m² per year. Additionally, each villa has 6 extra PV panels mounted on the roof, with a total capacity of 4 kWp, generating over 9 kWh/m² per year, to fulfil the community’s energy needs within the settlement (e.g., irrigation system and outdoor lighting). The energy generated by the PV panels is first used to satisfy the building and settlement energy demand. Then, it is stored in the ABB REACT+ system for private use during times when the renewable energy sources are not producing energy. Lastly, any excess energy is fed into the national power grid. Each villa’s technical room is equipped with an ABB REACT+ module, which includes a mobile accessible control dashboard through a dedicated app, to store the energy generated by the PV panels and use it at various times throughout the day. The energy storage system comprises 200 V Li-ion battery with 4 kWh storage capacity, 95% deep discharge, 1.6 kW charge power, and 2 kW discharge power. A 3.6 kW hybrid inverter is used to transform the direct current (DC) power generated by the PV panels to alternating current (AC) power for self-consumption, and vice versa, to allow the battery to store electricity as DC power. The integration of

78  Gloria Pignatta

Figure 5.3 Building-integrated technologies selected for the Italian villas: (a) Fibran insulation, (b) PV panels in Villa A, (c) PV panels in Villa B, and (d) ABB REACT+.

this energy storage system with the ABB load control system and the ABB HEMS (used for the management of the occupants’ indoor thermal comfort and their behaviors) increases the villas’ energy self-sufficiency, reduces their annual energy consumption by 20–30%, and ultimately leads to energy savings. Figure 5.3 illustrates the Fibran insulation panels, the solar PV panels on the roof of Villa A and Villa B, and the ABB REACT+ after their installation. Among the ZERO-PLUS solutions that were initially selected for the Italian case study, also the WindRail B60 system was considered as one of the potential energy production technologies. It is a modular and hybrid solar and wind turbine system that can be installed in the sloped roof of small residential buildings. However, during the construction phase of the villas, issues with permission and procedures arose, and it had to be replaced with additional PV panels. In addition to the ZERO-PLUS technologies, a low-temperature under-floor HVAC system has been installed in each villa to meet their heating and cooling needs. The system presents a digital control for thermoregulation and consists of an 8 kW air-to-water heat pump with an energy efficiency ratio (EER) of 3.8 and a coefficient of performance (COP) of 4.1. Ventilation is provided through a mechanically assisted system with 70% efficiency that incorporates a heat recovery mechanism. 3 Methodology The ZERO-PLUS approach, presented in Chapter 3, involves a combination of modeling, numerical simulations, analysis tools, continuous monitoring, and data collection, as well as pre- and post-occupancy evaluation (POE). This approach was applied to the Italian case study throughout the design, construction, and occupancy phases, which are further elaborated in Sections 3.1, 3.2, and 3.3, respectively.

5.1: Italian case study 79 3.1  Design phase

The design phase of the Italian case study settlement lasted approximately 2.5 years (2015–2017) and involved collaboration between various stakeholders, including the research team of the ZERO-PLUS project, architects, building owners, technology providers, housing developers, and planning authorities. The involvement of multiple stakeholders was crucial for the successful implementation of the ZEROPLUS approach, as it allowed for a diverse range of expertise and requirements to be integrated into the design process of the individual buildings and the settlement as a whole. In particular, the involvement of future occupants in the design process ensured that their needs and preferences were taken into account, leading to higher levels of occupant satisfaction. The process began with a site assessment, which included evaluating the microclimate, thermal energy performance, and environmental factors. Then, the design team worked on integrating advanced insulation, ZERO-PLUS technologies and other technical solutions, home energy management and load control systems, energy storage, and PV technology into the homes to achieve the NZES definition while also ensuring high levels of indoor comfort, optimal cost, and environmental sustainability. The main objective of the design process was to develop two energy-efficient demo villas and an NZES in accordance with the ZERO-PLUS guidelines, including the selection of suitable technologies, while meeting simultaneously specific design criteria and targets related to energy, cost, and environmental impact. These targets were met in practice and included: • Annual net-regulated energy1 consumption of 0–20 kWm2 (corresponding to an average of 70 kWm2 per year of regulated energy) • Renewable energy generation of at least 50 kWh/m² per year (on average) at the settlement level • ≥16% reduction in investment costs per building compared to costs for a single ZEB of similar performance Energy, economic, and environmental analyses were conducted following an iterative process aimed at evaluating and optimizing the performance of the Italian case study villas and settlement before the construction phase. These analyses were essential to identify the optimal configuration and set of technologies required to achieve the ZERO-PLUS targets (e.g., the thickness of insulation panels was optimized to decrease predicted energy consumption for the two villas, and at the same time, the number and type of PV panels were specified to achieve a total energy production of at least 50 kWh/m² per year).

1 Net-regulated energy = regulated energy use – renewable energy, where regulated energy use includes heating, cooling, domestic hot water, fans, pumps, and ventilation, while renewable energy includes energy production from building-integrated and settlement-integrated renewable energy technologies.

80  Gloria Pignatta Building thermal energy performance was evaluated through monitoring and dynamic simulations of energy consumption, renewable energy production, and indoor environmental quality. EnergyPlus engine, with DesignBuilder graphical interface v4–v6, was used for building modeling, energy load assessment, and building energy performance optimization. Different building models have been elaborated, including a baseline model, two reference cases for each villa, and an as-built model for each villa, similarly to what has been presented in Chapter 4 Part 2 for the UK case study. The typical meteorological year (TMY) used for the thermal energy simulations was provided by the EnergyPlus weather file database for the specific location of the case study. The as-built model simulations were calibrated and validated using data from dedicated meteorological and microclimate stations, as well as indoor environmental quality sensors, energy meters, and data loggers. The ABB storage systems were sized based on the estimated energy production data obtained for the specific case study location and PV panel typology. The economic analysis assessed the life cycle cost and payback period of the energy-efficient measures selected and implemented in the two villas. The aim was to evaluate the operating expenses associated with the energy and environmental systems selected during all the iterative steps of the design phase and identify the most cost-effective combination. The environmental analysis that was performed by using SimaPro software considered the reduction of carbon dioxide emissions, as well as the overall environmental impact of the settlement and all the integrated ZERO-PLUS technologies. Thanks to this type of analysis, both villas are finally designed and built to be sustainable, incorporating environmentally friendly features and microclimate strategies (as presented in Chapter 5 Part 2). This set of analyses enabled the identification of an optimal design plan that incorporates the most effective materials, technologies, and strategies to achieve net-zero and positive-energy targets while also considering economic feasibility and environmental impact. The results of each analysis informed and refined the building design, construction, and operation, resulting in a highly efficient and sustainable settlement. 3.2  Construction phase

During the construction phase of the Italian case study settlement (2017– August 2019), the main objective was to ensure that the optimal design plan was implemented as closely as possible to achieve the desired level of energy efficiency and NZES status. To this aim, both villas were built following the ZERO-PLUS approach presented in Chapter 3 and by implementing a dedicated commissioning plan, a change management plan, and a series of functional testing and pre-occupancy checks before the occupation phase. This quality control system was established through collaboration among relevant stakeholders to guarantee adherence to design and performance standards during the construction process.

5.1: Italian case study 81 The performance of the completed villas was evaluated during the phase of the pre-occupancy checks (June 2018–July 2018 for Villa A and February 2019– March 2019) that took place immediately after the construction phase and included surveys, short-term indoor and outdoor monitoring campaigns, and energy metering. The campaign involved building diagnostic (i.e., air permeability tests, U-value tests, infrared thermography, co-heating tests (Bauwens & Roels, 2014)) and spot measurements taken for two weeks using portable microclimatic stations for indoor (including sensors for air temperature, relative humidity, mean radiant temperature, air velocity CO2 and VOC, vertical radiant asymmetry, and heat flow) and outdoor (equipped with sensors for air temperature, relative humidity, surface temperature, wind speed, CO2, global solar and reflected radiation, and light intensity) and individual sensors (Figure 5.4) (Meir et al., 2020). The purpose of the

Figure 5.4 Example of monitoring sensors installed Italian Villa A: (a) blower-door test for air permeability, (b) thermal image taken indoor by a FLIR thermal camera, (c) Tinytag probe for indoor air temperature and relative humidity, (d) Tinytag probe for surface temperature, (e) heat flux plate for thermal resistance of external walls, (f) U-value test for thermal transmittance and heat flow, and (g) portable indoor microclimatic station.

82  Gloria Pignatta short-term monitoring was to assess the buildings’ performance in free-running mode, prior to the thermal plant becoming operational, and before occupancy. The data obtained from the short-term and long-term monitoring (discussed in Section 5) were used to validate the energy simulation models of the two villas under the as-built scenario. Overall, the construction phase was completed successfully, resulting in two energy-efficient villas that met the performance targets established during the design phase. The main characteristics and technologies of the two as-built ZEROPLUS single-family demonstration villas are reported in Sections 2.2 and 2.3, respectively. 3.3  Long-term monitoring and occupancy phase

After the construction phase, the performance of the Italian case study settlement was evaluated through extensive monitoring activities. The continuous monitoring during operation involved collecting real data on climate conditions, indoor environmental quality, energy consumption, and user behavior for a period of about one year (July 2019–August 2020), which partially occurred during the COVID-19 pandemic. The occupancy phase in Villa A started in August 2018, and in Villa B in March 2019. The collected data were analyzed to assess the actual performance of the buildings and settlement in operation (i.e., energy consumption, energy generation, indoor and outdoor microclimate), compared to the predicted performance from the design stage. Long-term monitoring equipment were installed in Villa A and Villa B to perform the post-occupancy evaluation (which included spot measurements, continuous monitoring, surveys and questionnaires for the occupants, statistical and qualitative analysis of their responses – more details are provided in Chapter 11) and collect performance data to be transmitted to the WebGIS platform. This platform was designed to manage monitoring and performance evaluation. The collected data were first transmitted to a KNX router via Ethernet, and then to the WebGIS platform through a REST API (Richardson & Ruby, 2007). The collected data were transmitted in real time with 15-minute sampling intervals and were used also to ensure timely interventions and troubleshooting of the installed technologies. Figure 5.5 shows some of the sensors installed in Villa A, including the air quality sensor (for CO2 concentration, indoor air temperature, and relative humidity recording), the HVAC thermostat, the on-site DEVIS meteorological station installed on the roof and its display (for outdoor air temperature, relative humidity, wind speed, wind direction, and solar radiation recording) (Bauwens & Roels, 2014). In addition to these monitoring equipment, energy meters and inverter were installed to collect data on energy consumption (for heating, cooling, domestic hot water, fans, pumps, and ventilation, as well as total operation of each villa) and energy production from the PV panels, respectively. Occupancy profiles were monitored via room presence and luminance sensors and sensors installed on windows and doors to record their open and close configuration.

5.1: Italian case study 83

Figure 5.5 Long-term monitoring sensors in Italian Villa A: (a) CO2 and relative humidity sensor, (b) HVAC thermostat, (c) wireless DAVIS meteorological station installed on the roof, and (d) display of the DAVIS meteorological station. Table 5.5  Measurement range, resolution, and accuracy of the installed monitoring sensors Measurement

Range

Resolution

Accuracy (±)

Space temperature (°C) Space CO2 level (ppm) Space illumination (Lux) Building HVAC electric Power (W) Relative Humidity (%) Wind speed (m/s) Global radiation (W/m2) Outdoor air temperature (°C)

0–50 0–2,000 0–500 0–25,000 1–100 1–50 0–2,000 −40–64

0.1 20 0.2 0.1 1 0.4 50 0.1

0.5°C 40 ppm 0.5 Lux 0.1% 4% 5% 10% 1°C

Table 5.5 summarizes the range, resolution, and accuracy of the sensors used to measure the monitored parameters. Figure 5.6 shows the profiles of the variables (i.e., indoor and outdoor temperatures in °C, HVAC power in W, solar radiation in W/m2, wind speed in m/s, CO2 in ppm, and outdoor relative humidity in %) monitored during the long-term monitoring campaign for the month of August 2019. The temperature inside the house was controlled to stay between 23 and 25°C, while the outdoor temperature ranged from 16.4°C to 36.2°C. Humidity levels and wind speed reached 93% and 12.5 m/s, respectively. Maximum solar radiation on the site was 867 W/m2, and HVAC power reached a maximum value of 2,500 W. The HVAC system improved indoor thermal comfort and air quality, with an average CO2 level of 545 ppm, which is within the acceptable range (i.e., 400–600 ppm) according to the European standard NBN EN 13779. However, occupants experienced brief periods of high CO2 levels. Examining HVAC power consumption and space temperature variation revealed that power spikes were associated with different space temperatures at

84  Gloria Pignatta

Figure 5.6  Profiles of the variables monitored in Villa A for the month of August 2019.

different times. These spikes can be attributed to the start of the heat pump, which requires significant power to turn on and provide heating or cooling. It appears that occupants adjusted the HVAC set point temperature, which affected the space temperature. The post-occupancy evaluation (POE) protocol included the involvement of the occupants’ feedback collected via four scheduled surveys and interviews distributed along one year (June 2019–August 2020 for both villas), and it was applied by a dedicated supporting team. This phase of the project involved the collaboration of the main stakeholders that together elaborated a specific informative document named “welcome package,” which aimed to instruct the occupants on how to use and maintain the building and their advanced technologies and systems. It also informed the occupants about the collected data and reasons for collection, the type of monitoring campaign, and instruction about surveys and privacy. Additionally, the POE comprised quantitative and qualitative data and helped with the identification of design or behavioral barriers responsible for malfunctions and solutions to remediate the identified problems. Maintenance was supported by a problem

5.1: Italian case study 85 identification procedure, a risk registry, the WebGIS platform, and related guidelines which were provided to all stakeholders involved in the operational management of the settlement and, in particular, to the dedicated rescue team. Real-time analysis of data on energy production and consumption have also been used to continuously inform energy management at the settlement level, the occupants, the rescue team, and the post-occupancy evaluation results. An internal monitoring and verification (M&V) protocol was developed to include quality control procedures for each phase of the project, from postinstallation to post-occupancy phase. The results from one-year monitoring showed that both villas achieved the energy consumption target in terms of net-regulated energy thanks to the implementation of ZERO-PLUS guidelines and technologies. This represents a significant improvement compared to a typical Italian building, where the primary energy consumption is usually around 180–200 kWh/m² per year. The indoor environmental quality was also found to be satisfactory, with comfortable temperature and humidity levels throughout the year. Furthermore, the user feedback from the occupants of the buildings was positive, with high levels of satisfaction regarding the thermal comfort, air quality, and lighting conditions. Overall, the monitoring and occupation phase provided valuable insights into the actual performance of the settlement, demonstrating that the ZERO-PLUS approach can effectively deliver comfortable and energy-efficient buildings in real-world conditions. 4 Results Following the ZERO-PLUS approach, an investment cost reduction of about 25% (more than the economic target set at 16%) has been achieved for both villas thanks to the shift between the single-building design approach and the multi-building design approach, where the cost for the extra performance of high-performing buildings is mitigated by the benefit derived by the application of the economy of scale. The energy optimization results showed that the implementation of energy conservation measures and energy management solutions resulted in a net-regulated energy consumption lower than the ZERO-PLUS target of 20 kWh/ m2 per year. The renewable energy systems (i.e., PV panels) generate about 50 kWh/m2 per year at the settlement level, meeting the energy production target. The PV panels and energy storage systems together provided a sufficient amount of energy to run the two villas and energy flexibility to meet the energy demand of the community’s energy needs within the settlement. Furthermore, a total saving of 49.6 kgCO2eq/m2 per year was achieved at the settlement level. Table 5.6 summarizes the achieved performance results of the two villas and compare them to the ZERO-PLUS targets. The results derived by the numerical simulation have been obtained by modifying the as-designed parameters with the as-built parameters derived from the monitoring campaign. Table 5.7 reports the measured U-values and air permeability values used for the calibration of the building models.

86  Gloria Pignatta Table 5.6 Cost reduction and energy results compared to the ZERO-PLUS targets in the Italian case study Villa A

Villa B

ZERO-PLUS target

Investment cost reduction per villa

24.8%

24.8

Net-regulated energy consumption at building level Regulated energy consumption at building level Renewable energy production at settlement level Carbon emission reduction at settlement level

6 kWh/m² per year

4.2 kWh/m² per year

≥16% compared to the costs for a single NZEB of similar performance (reference model) 23 kgCO2/m² per year

Source: Mavrigiannaki, Gobakis, et al. (2021); Mavrigiannaki, Pignatta, et al. (2021).

Table 5.7 U-values and air permeability values used for the calibration of the buildings’ models Element

Villa A

Villa B

As-designed As-built result As-designed As-built result target target External walls (W/m2 k) Roof (W/m2 k) Ground floor (W/m2 k) Air tightness rate h-1 @ 50 Pa

0.12 0.117 0.167 0.5

0.25 – – 0.575

0.12 0.117 0.167 0.5

0.164 – – –

5 Barriers For the adoption of the innovative ZERO-PLUS approach and implementation of advanced technologies, a number of barriers have been identified and mitigated in the Italian case study settlement. The first encountered barrier was the lack of experience of the conservative construction company in the installation and a lack of knowledge in the performance. Occupants’ concern was on the maintenance of building’s systems, and they were skeptical about their performance and cost. There was the fear to be the first adopters of novel technologies, and time was needed to promote the benefits of a new way of building, thinking, managing, demanding, and approaching to new high-performing constructions and to reduce the resistance to change the business-as-usual. The monitoring period of ZERO-PLUS included the first COVID-19 outbreak. Despite the challenges, the monitoring activities, both the monitoring and the

5.1: Italian case study 87 post-occupancy evaluation (POE) surveys and interviews, continued to run, to the extent possible. Thanks to the ZERO-PLUS strategies employed to reduce the resistance to change among the key partners in the Italian case study, it was possible to contribute to a national market uptake of energy-efficient buildings and settlements and energy regulations as presented in Chapter 2. 6 Conclusion In conclusion, the Italian case study settlement was successfully realized following the ZERO-PLUS approach despite several barriers and regulatory and technical challenges. It demonstrated the feasibility of achieving the energy, economic, and environmental targets set in the ZERO-PLUS project in a temperate and Mediterranean climate. The combination of passive design measures and highly efficient technologies implemented in the villas has enabled a significant reduction in energy consumption, CO2 emissions, and operating costs. The renewable energy production target was just short of the target (i.e., by 4.8%), which may be the result of a seasonal variation, such as cloud cover or dust. However, the villas have exceeded net-regulated consumption expectations by performing as net-zero dwellings. Again, this shift can be attributed to modeling assumptions, construction variation, and occupant behavior. The monitoring campaigns carried out have provided valuable insights into the actual performance of the buildings and the renewable energy systems. In line with reduced net-regulated consumption, the Italian settlement has increased total energy conservation and CO2 emission reductions in the in-use stage based on actual data against the as-built projections, enhancing their impact. As their energy conservation was improved in the actual case overall, this unimproved CO2 emissions reduction attributed to the higher-than-projected space heating consumption and the change in fuel proportions. The ZERO-PLUS modeling approach for simulating the expected building and settlement performance at the design phase had produced reliable performance results. Moreover, keeping a record of the changes that might occur during construction is useful in understanding possible performance deviations. The involvement of a multidisciplinary team of stakeholders, including architects, engineers, technology providers, and researchers, has been essential for the successful implementation of the ZERO-PLUS approach in the Italian case study settlement. This case study highlights the potential for implementing highly efficient and sustainable residential settlements and provides valuable lessons for future projects. The development of replicable and scalable solutions for zero- and positive-energy districts will be critical in the transition toward a more sustainably built environment. References Bauwens, G., & Roels, S. (2014). Co-heating test: A state-of-the-art. Energy and Buildings, 82, 163–172. https://doi.org/10.1016/J.ENBUILD.2014.04.039

88  Gloria Pignatta Beck, H. E., Zimmermann, N. E., McVicar, T. R., Vergopolan, N., Berg, A., & Wood, E. F. (2018). Present and future Köppen-Geiger climate classification maps at 1-km resolution. Scientific Data, 5(1), 1–12. https://doi.org/10.1038/sdata.2018.214 Climate & Weather. (2023). Climate & Weather Averages in Granarolo dell’Emilia e Viadagola, Italy. Retrieved February 10, 2023, from www.timeanddate.com/wea ther/@3163830/climate H2020 Project ZERO-PLUS. (2015). Achieving near Zero and Positive Energy Settlements in Europe using Advanced Energy Technology. www.zeroplus.org/index.php/ Mavrigiannaki, A., Gobakis, K., Kolokotsa, D., Kalaitzakis, K., Pisello, A. L., Piselli, C., Laskari, M., Saliari, M., Assimakopoulos, M.-N., Pignatta, G., Synnefa, A., & Santamouris, M. (2021). Zero energy concept at neighborhood level: A case study analysis. Solar Energy Advances, 1, 100002. https://doi.org/10.1016/j.seja.2021.100002 Mavrigiannaki, A., Pignatta, G., Assimakopoulos, M., Isaac, M., Gupta, R., Kolokotsa, D., Laskari, M., Saliari, M., Meir, I. A., & Isaac, S. (2021). Examining the benefits and barriers for the implementation of net zero energy settlements. Energy and Buildings, 230. https://doi.org/10.1016/j.enbuild.2020.110564 Meir, I. A., Isaac, S., Kolokotsa, D., Gobakis, K., & Pignatta, G. (2020). Towards zero energy settlements – a brief note on commissioning and POE within the EU ZERO-PLUS Settlements. IOP Conference Series: Earth and Environmental Science, 410(1). https:// doi.org/10.1088/1755-1315/410/1/012038 Richardson, L., & Ruby, S. (2007). Restful Web Services (1st ed.). Sebastopol, CA: O’Reilly.

5

Part 2: Community-level strategies for microclimate mitigation and energy efficiency improvement Cristina Piselli, Silvia Cavagnoli, Anna Laura Pisello, Claudia Fabiani, and Franco Cotana

1 Introduction The phenomenon of global population growth has markedly altered the microclimate of urban areas. Whether due to the intensification of human activity or to other parameters, such as city characteristics or the shape and arrangement of buildings (Santamouris, 2014), urban areas are now characterized by a higher local temperature than nearby rural areas. Indeed, one of the most influential factors in microclimate change is the heat released by structures, which are especially common in more urbanized areas or larger city centers (Rizwan et al., 2008). The ability of the most common building materials to absorb heat during the day and release it at night contributes to the increase in local ambient temperatures in the built environment, a phenomenon known as urban heat island (UHI). UHI also results in increased anthropogenic emissions, for example, due to the increased use of systems to achieve indoor comfort, especially in summer, when this phenomenon has the greatest impact (Kim & Brown, 2021). From these issues, there is the need to find methods and strategies to mitigate this phenomenon. Several studies propose to intervene on material characteristics and thermal-optic properties, particularly for roof applications. As a matter of fact, according to Li et al. (2014), using green or cool roofs characterized by high albedo values results in a cooling phenomenon of the surface and near-surface temperature. Supporting this study is the work of Onishi et al. (2010), who, in addition to UHI, also consider land use and land cover (LULC) and land surface temperature (LST). The study is primarily based on parking lot coverage with various percentages of grass amounts, and from the results analysis, the values are as expected, that is, a decrease in temperature is found. These strategies, in addition to reducing the increase in temperature, also reduce energy consumption that would be caused by the various systems of buildings. Buildings are responsible for around 40% of the energy consumption in Europe (European Commission, 2018). A large part of this energy is associated to heating, ventilation, and air-conditioning (HVAC) of buildings, as addressed in this study. However, also, interior lighting is non-negligible. For this purpose, it is useful to find a strategy that takes advantage of daylight as much as possible, reducing the use of artificial light or otherwise combining both daylight and artificial light in DOI: 10.1201/9781003267171-7

90  Cristina Piselli et al. the most efficient way. In this regard, the study of Carletti et al. (2017) shows the importance of exploiting daylight (considering factors such as the structure position and shading or local climate conditions) and how this reduces energy costs and total consumption, reaching the standards of a nearly zero energy building (nZEB). On a large scale, the UHI phenomenon is manifested as global warming, characterized by high amounts of greenhouse gas emissions (GHG), negatively affecting the frequency of events, such as floods or sea level rise. For this reason, it is needed to start from the small scale (i.e., building and urban planning scale) to mitigate the effect of urban heat island and, consequently, climate change, achieving the goal of having a similar temperature between urbanized and rural areas (Ciancio et al., 2020). Connecting to this research sphere, the purpose of this chapter is to present the methodology developed within the Horizon 2020 (H2020) ZERO-PLUS project to assess the influence of inter-building microclimate mitigation strategies on outdoor comfort and building thermal energy performance in net-zero energy settlements. 2 Methods According to the purpose of the proposed methodology, as aforementioned, the approach defined consists of the following steps: • Microclimate modeling and analysis of the considered settlement in its current design configuration, that is, so-called “reference” scenario. • Design of mitigation scenarios involving passive strategies to be implemented at settlement scale, for example, vegetation, cool surfaces, etc. • Implementation of the selected mitigation strategies in the microclimate simulation model and analysis of the “mitigated” scenarios. • Generation of different site-specific weather files to be used in building thermal energy dynamic simulation for more accurate predictions: “reference” and “mitigated” conditions. • Dynamic simulation of the considered buildings in the settlement in the “reference” and the “mitigated” weather conditions. • Critical evaluation of the potential benefits achievable in terms of energy saving and indoor and outdoor comfort improvement. • Sensitivity analysis aimed at comparing the impact of the investigated microclimate mitigation inter-building strategies. The proposed methodology was presented in detail in two publications by the same authors (Castaldo et al., 2018; Cardinali et al., 2020) and is described in the following sub-sections. 2.1  Community-level analysis and microclimate simulation

The initial step of the proposed methodology is the microclimate analysis related to the simulation of outdoor local microclimate conditions on the settlement scale.

5.2: Community-level strategies for microclimate mitigation 91 First, the “reference” scenario is modeled, which represents the actual local climate conditions. In this case, a limited portion of the land around the buildings is considered that needs improvement techniques within the ZERO-PLUS project. The simulation of the outdoor microclimate conditions for this scenario is carried out using the ENVI-met software version 4. The information on buildings and settlement is obtained from the technical drawings, and where necessary, details are integrated with Google Earth. The models developed in ENVI-met are used to simulate the hottest summer day and the coldest winter day for 24 hours, where parameters such as air temperature and relative humidity can be set with hourly values. As for the weather data to be used as input in the simulations, these are provided by MeteoBlue (2016). The other scenarios considered are those that implement microclimate mitigation strategies (“mitigated” scenarios) in order to optimize local microclimate conditions in the settlement and are as follows (Castaldo et al., 2018): • “Green” scenario. Includes a percentage increase in vegetation based on the architecture and landscape of the settlement and the application of permeable pavements. • “Cool” scenario. Involves the application of cool materials for buildings and pavements with an increase in the solar reflectance capability of the external surfaces of the built environment. • “Combined” scenario. The combination of the preceding strategies. Table 5.8 reports the values of albedo for the building envelope and external surface materials in the “reference” and the three “mitigated” scenarios. 2.1.1 Sensitivity analysis

The sensitivity analysis is carried out in order to determine the specific impact of each considered mitigation strategy on the local microclimate of the settlement. In detail, the separate impact of each optimization solution, that is, green, cool, and combination of both, is quantified in terms of minimum, maximum, and average Table 5.8  Albedo values of surfaces in “reference” and “mitigated” scenarios Material

External wall Pitched roof Asphalt road Pavement Loamy soil Vegetation (grass, trees, hedges) * Permeable.

Albedo [-] Reference

Green

Cool

Combined

0.40 0.15 0.20 0.20 0.00 0.20

0.40 0.15 0.20* 0.30* – 0.20

0.71 0.58 0.60* 0.67 0.00 0.20

0.71 0.58 0.60* 0.67* – 0.20

92  Cristina Piselli et al. outdoor air temperature variation and minimum, maximum, and average outdoor air relative humidity variation. Such evaluation is carried out by considering the hottest hour of the warmest day simulated in the “reference” scenario. 2.2  From community-level to building-level analysis

For the building-level analysis, the followed method is based on several steps. First, tailored weather files are developed for the “reference” and the “mitigated” scenarios to be input in thermal energy dynamic simulation, as described in SubSection 2.2.1. In a second step, the new meteorological data are used as weather boundary conditions for building dynamic simulation in the four settlement scenarios (i.e., “reference,” “green,” “cool,” and “combined”) (Cardinali et al., 2020). The software selected for building dynamic simulation is EnergyPlus (Crawley et al., 2000) with DesignBuilder graphical interface. Before carrying out the simulations with the developed weather files, building models are optimized in order to represent the final as-built configuration of nZEBs according to the requirements of the ZERO-PLUS project (Castaldo et al., 2018). Therefore, one weather file at a time is entered to perform building simulation in order to quantify the benefits (on average) of implementing different microclimate mitigation strategies. All in all, by simulating the buildings with the developed weather file, the maximum achievable benefits due to the combination of the cool and green strategy can be estimated. Hence, the analysis starts from a reference, building up to a nearly zero-energy settlement. 2.2.1 Development of weather files

Starting from the available hourly data obtained from the ENVI-met outdoor microclimate simulation outputs, a dedicated MATLAB code is implemented to generate hourly values of the available parameters for an entire year. Outdoor microclimate simulation provides dry-bulb temperature, direct and diffuse radiation, and wind speed for one day in summer and one in winter for each scenario. Therefore, using Meteonorm software, which allows to develop used defined weather files starting from a database of meteorological data at various points around the world, a weather file for the case study (.epw format) is developed in the “reference” and “mitigated” microclimate scenarios. For the “combined” scenario, which is the optimized one in terms of outdoor microclimate simulation, the weather file is developed starting from both the average output values and the values in the position characterized by the maximum mitigation effect. The procedure is described in detail in Castaldo et al. (2018). The developed weather files are the following: • • • •

“Reference” weather file: “reference” microclimate conditions “Cool” weather file: mitigated microclimate conditions with cool surfaces “Green” weather file: mitigated microclimate conditions with vegetation “Combined_average” weather file: combination of the microclimate mitigations “cool” and “green” (average value around the settlement)

5.2: Community-level strategies for microclimate mitigation 93

Figure 5.7 Case study settlement: (a) plan view, (b) southwest (left) and southeast (right) 3D views of the microclimate simulation model, and (c) building dynamic simulation model.

• “Combined_maximum” weather file: combination of the microclimate mitigations “cool” and “green” (maximum value around the settlement) 2.3  Case study

The proposed methodology is replicable and can be applied in any suitable case study settlement. In the framework of the Horizon 2020 ZERO-PLUS project, the procedure was implemented in all case study settlements. This chapter reports the analysis carried out for the Italian case study settlement as an example. This case study is located in Granarolo dell’Emilia, Bologna, in central Italy, and consists of two single-family houses built as part of a settlement and the surrounding outdoor area (Figure 5.7). According to the project purposes, the buildings were designed – and, therefore, modeled – based on high energy efficiency, low emissions, and cost-effectiveness principles, using innovative materials and technologies aimed at minimizing energy demand and producing renewable energy. The two buildings are similar in geometry and dimensions, construction characteristics, and HVAC system and have the same orientation and boundary conditions. The characteristics of the Italian case study settlement are described in detail in Chapter 5 Part 1. 3 Results 3.1  Outdoor microclimate simulation

The results of the microclimate simulations of the different scenarios in summer and winter configuration refer to 24-hour simulations, and the main parameters analyzed are as follows: • Air temperature (T air) (°C) • Relative humidity (RH air) (%)

94  Cristina Piselli et al. • Wind speed (m/s) • Mean radiant temperature (°C) The graphs depicted in Figure 5.8 are made by exporting data at 0.9 m height from the ground in the time when maximum air temperature occurs in summer. These data are analyzed also in winter conditions at the time of maximum air temperature (6 or 12 hours from minimum air temperature). Indeed, for the comfort evaluation in winter, daytime hours are selected. Moreover, the Leonardo ENVI-met application is used to export data toward determining the external comfort indices PET (physiological equivalent temperature) through RayMan software. However, this analysis is not discussed in this chapter. Regarding the “reference” scenario, the results for summer report a daily air temperature variation between 21°C and 40°C at 2:00 and 14:00, respectively. Moreover, the relative humidity range is between about 22% and 25%, while the average radiant temperature is between 51.1°C and 71.5°C, and the wind has speeds between 0 and 0.8 m/s. For the results in winter conditions, an air temperature range of 6.5°C to 8.2°C is observed, while relative humidity ranges from 53% to 67%. In this case, the average radiant temperature varies between a minimum of 12.8°C and a maximum of 56.6°C, while the maximum wind speed is 2.4 m/s. Figure 5.9a (Cardinali et al., 2020) depicts the distribution of outdoor air temperature in the “reference,” “green,” “cool,” and “combined” scenario at 15:00. In summer conditions, the comparison of the “green” scenario and the “reference” one shows a good mitigation of air temperature, with a decrease of about 1.4°C at peak time. Moreover, by using the cool materials (“cool” scenario), a lower but more spatially widespread mitigation effect is obtained. Finally, by comparing the “reference” and the “combined” scenarios, the maximum air temperature decrease equal to 1.5°C is found. As for relative humidity, the major increase (about 5%) is estimated in the “green” and the “combined” scenario. As regards the mean radiant temperature, there is a maximum decrease of about 5°C in the “green” configuration, due to the shading effect of vegetation to the incoming solar radiation. Conversely, in the “cool” scenario, an increase in mean radiant temperature is found due to the presence of reflective materials on the paving surfaces serving the two houses. As for wind speed, in the “green” scenario, the presence of the hedge does not allow air circulation at 0.9 m and, therefore, has the effect of reducing the wind speed near the buildings. This generates a reduction in convective mixing in the area, which is perceived also in the “combined” scenario. In winter conditions, the results for mitigation scenarios dictate a lower overall mitigation effect. As for air temperature, a slight decrease is assessed in all scenarios analyzed. Regarding relative humidity, there is a non-negligible effect in the green scenario (up to 8% increase), while in the “cool” one, no major difference is observed. In the case of the mean radiant temperature, the “cool” scenario has higher values (up to 3°C difference), while the “green” one seems not to affect this parameter in winter conditions. Negligible differences in terms of wind speed are registered in winter by comparing the different simulated configurations.

5.2: Community-level strategies for microclimate mitigation 95

Figure 5.8 Summer conditions: air temperature and relative humidity values in the (a) “reference,” (b) “green,” (c) “cool,” and (d) “combined” scenario at peak air temperature time.

96  Cristina Piselli et al.

Figure 5.9 (a) Summer air temperature at 15:00 in the four settlement scenarios and (b) percentage reduction in net-regulated energy at building scale. Source: Cardinali et al. (2020).

5.2: Community-level strategies for microclimate mitigation 97 Table 5.9 Effect of the different mitigation strategies in terms of outdoor air temperature and relative humidity variations Scenario

m3 % % cool ΔT air ΔT air ΔT air ΔRH air ΔRH air ΔRH air trees grass max [K] min [K] ave [K] max [%] min [%] ave [%]

Green + 356 + 10.3 – + 0.10 Cool – – + 26.5 + 0.16 Combined + 356 + 10.3 + 26.5 – 0.67

– 1.35 – 0.70 + 0.14

– 0.12 – 0.09 – 0.09

+ 4.90 + 0.09 + 0.91

+ 0.05 – 0.20 – 0.18

+ 0.50 + 0.11 + 0.12

Table 5.9 summarizes the results of the sensitivity analysis on the effect of the different mitigation strategies in terms of outdoor air temperature and relative humidity variations. Variations are calculated with respect to the “reference” scenario, which presents 560 m3 of trees, 38.5% of grass cover, and 0% of cool surfaces. First, the increase of vegetation percentage produces a positive effect in terms of outdoor air temperature reduction in the case study settlement. The decrease of the outdoor air temperature due to the evapotranspiration also generates a slight increase in air relative humidity. On the other hand, the implementation of cool surfaces generates a slighter passive cooling effect. More in detail, the microclimate conditions in the case study settlement appear to be more sensitive to the introduction of grass, even if the increase of the greenery percentage in the area, that is, around 10% of grass and 356 m3 of trees, is not very high. Nevertheless, the case study settlement experiences a sensible reduction of average outdoor air temperature with consequent slight increase of average air relative humidity due to the evapotranspiration. When considering the combination of green and cool strategies, results are similar to the “cool” scenario. Globally, this analysis demonstrates that while designing microclimate mitigation strategies, it is important to take into account the sensitivity of the settlement to both the percentage of the strategy implemented and its geometrical-physical characteristics. 3.2  Building thermal energy dynamic simulation

Microclimate strategies have influence also on the energy behavior of buildings by acting on the outdoor boundary conditions. Indeed, the proposed procedure allows to assess the thermo-energy performance of the building, considering its insertion in the settlement. As depicted in Figure 5.9b, the “combined” scenario provides the most suitable conditions for the operation of the building in the settlement, mainly thanks to the lower local air temperature values during summer. As a result, within the “combined_maximum” weather file conditions, the reduction in net-regulated energy (defined in the ZERO-PLUS project as the building energy need for heating, cooling, domestic hot water, fans, pumps, and ventilation minus the total energy production from renewable sources) is up to 22% compared to the “reference.” In the “combined_average,” the energy saving is equal to about 12%, while in the other

98  Cristina Piselli et al. two scenarios, the saving is smaller. Moreover, when progressively enlarging the mitigation area, that is, the area all around the building where mitigation strategies are implemented, an increasing reduction of net-regulated energy can be achieved (Cardinali et al., 2020). In particular, the maximum achievable reduction within the “combined_average” weather file conditions is equal to about 20%. Thereafter, the further enlargement of the intervention area does not provide additional benefits in terms of energy savings for the single building within the settlement. Finally, at the building level, the orientation is studied to optimize the electricity production by the photovoltaic panels installed on the building roof. The optimal orientation is 85° rotated to the north. Thanks to this arrangement, an increase in energy production of about 12.3% is estimated, compared to the less-effective orientation. This also results in a decrease in operational CO2 emissions, which are analyzed for the two “combined” scenarios compared to the “reference” scenario. As a matter of fact, within the “combined_maximum” weather conditions, a decrease in CO2 emissions of 3.5% is achievable under spring/summer conditions (from April to September), while within the “combined_average,” there is a reduction of around 4.0%. 4 What’s next? Following the ZERO-PLUS project, other studies have been carried out with the same aim, that is, defining innovative strategies for microclimate mitigation and investigating their effect on building energy consumption. A follow-up study carried out by Piselli et al. (2020) highlights the benefits of creating net-zero energy settlements and analyzes their performance from the inter-building point of view not only in terms of generating improved local outdoor conditions but also in terms of the reduction of building energy consumption due to the milder conditions of operation of the systems as a result of climate mitigation. This study estimates energy savings up to 24% thanks to the combination of these effects. Indeed, achieving mitigated external and internal microclimate conditions for citizens and users is important for both ensuring well-being in the built environment and improving the final energy performance of buildings. In order to assess the role of users in this panorama, another follow-up study by Piselli et al. (2021), related to the same case study, analyzes different occupant behavior scenarios with the aim to evaluate the relationship between the users and the building. With similar aim, the study carried out by Ascione et al. (2020) evaluates the performance of an nZEB by monitoring the building in its relationship with the outside world in order to assess the actual benefits that could be obtained with the use of renewable energy systems. This study is based on various applications that could be incorporated into buildings, including the idea of external directionally selective blinds or controlled mobile devices capable of protecting the building during the hottest hours of the day, that is, when the rays are directly aimed at the building. Linked to renewable energies, there is a further study that encourages the application of photovoltaic panels in buildings while also paying attention to the surrounding vegetation (Berardi & Graham, 2020), in line with the present study. This study

5.2: Community-level strategies for microclimate mitigation 99 implements these solutions with both cool materials and the inclusion of trees along the road. However, the authors stress the importance of properly designing the integration of trees in order not to negatively influence the performance of photovoltaic panels on roofs. The extent of these topics is recognized in various countries around the world, including Egypt, where several studies have looked at ways to mitigate the local microclimate, especially in summer. They recognize that microclimate conditions are strongly influenced by parameters such as the layout of buildings or the albedo of materials, in agreement with other studies already mentioned. The attempt made in the study by Fahmy et al. (2020) is to reduce building energy consumption by designing mitigated urban forms. On the other hand, a work by Romano et al. (2021) presents a platform for the assessment of the effects of the interaction between buildings in the same district, by evaluating their mutual shading, and the urban heat island effects in summer. This approach also involves the calculation of the influence on the energy demand of buildings, as highlighted by the present study. In addition to the aforementioned studies, the research topic is still under discussion in several countries, with a focus on renewable energy sources, energy consumption, emissions reduction, and microclimate control in order to achieve efficient net-zero energy communities, as summarized in the review by Ullah et al. (2021). 5 Conclusions In recent years, the world population has been growing, and most of this population lives in urban centers, where most of energy consumption and emissions are gathered. As a matter of fact, the environmental characteristics of urban centers and areas with less population density, that is, rural areas, are different. Indeed, rural areas are characterized by lower temperatures than urban centers, which are instead affected by the urban heat island phenomenon. In an increasingly hot planet where the number of people is constantly increasing, it is important to find efficient solutions. The rise in temperatures in the outdoor climate and the increase in energy demand from buildings have led the research community to focus on developing strategies to reduce these phenomena. These solutions do not only bring benefits from a climatic and economic point of view but also lead people to achieve indoor and outdoor comfort conditions. In particular, this research work focuses on the design and application of novel microclimate modeling and simulation approach for the assessment of the influence of outdoor microclimate mitigation strategies on both outdoor comfort and building energy performance in net-zero energy settlements. In this work, the proposed methodology is implemented in a case study settlement located in Granarolo dell’Emilia, Bologna, Italy. To this aim, a “reference” and different “mitigated” scenarios in terms of local microclimate conditions are modeled and compared. One of the key points of this work is to demonstrate how implementing tailored inter-building microclimate mitigation strategies allows building energy savings by up to 22% and a consequent reduction in CO2 emissions.

100  Cristina Piselli et al. It is from these concepts that the idea of “net-zero energy” was derived, especially in relation to the construction sector, which is responsible for the highest demand for energy compared to other sectors. As a follow-up of this study, other studies have focused on these issues, developing new strategies by considering their impacts and characteristics. In most of the studies, the results are positive, and the proposed solutions are able to improve the energy performance of buildings. Since this is a problem that affects the entire planet and different countries are looking for solutions to counteract these phenomena, an effective approach could be the interaction and integration to find solutions that can be used in different countries, adapting them to the local environmental and climatic characteristics. Acknowledgments The authors wish to thank the Italian Ministry of Research for supporting the young researcher PRIN project NEXT.COM (20172FSCH4_002). Additionally, the authors would like to thank the Italian funding program Fondo Sociale Europeo REACT EU – Programma Operativo Nazionale Ricerca e Innovazione 2014–2020 (D.M. n.1062 del 10 agosto 2021) for supporting their research though projects “Efficientamento energetico e rinnovabili nella catena del freddo e nel sistema edificio-impianto,” “Red-To-Green,” and “Comunità energetiche resilienti per la valorizzazione del benessere ambientale, del risparmio energetico e della valorizzazione del patrimonio mediante gestione multidominio di dati human centric.” References Ascione, F., Borrelli, M., De Masi, R. F., & Vanol, G. P. (2020). Nearly zero energy target and indoor comfort in Mediterranean climate: Discussion based on monitoring data for a real case study. Sustainable Cities and Society, 61, 102349. https://doi.org/10.1016/j. scs.2020.102349 Berardi, U., & Graham, J. (2020). Investigation of the impacts of microclimate on PV energy efficiency and outdoor thermal comfort. Sustainable Cities and Society, 62, 102402. https://doi.org/10.1016/j.scs.2020.102402 Cardinali, M., Pisello, A. L., Piselli, C., Pigliautile, I., & Cotana, F. (2020). Microclimate mitigation for enhancing energy and environmental performance of near zero energy settlements in Italy. Sustainable Cities and Society, 53, 101964. https://doi.org/10.1016/j. scs.2019.101964 Carletti, C., Cellai, G., Pierangioli, L., Sciurpi, F., & Secchi, S. (2017). The influence of daylighting in buildings with parameters nZEB: Application to the case study for an office in Tuscany Mediterranean area. Energy Procedia, 140, 339–350. https://doi.org/10.1016/j. egypro.2017.11.147 Castaldo, V. L., Pisello, A. L., Piselli, C., Fabiani, C., Cotana, F., & Santamouris, M. (2018). How outdoor microclimate mitigation affects building thermal-energy performance: A new design-stage method for energy saving in residential near-zero energy settlements in Italy. Renewable Energy, 127, 920–935. https://doi.org/10.1016/j.renene.2018.04.090 Ciancio, V., Salata, F., Falasca, S., Curci, G., Golasi, I., & de Wilde, P. (2020). Energy demands of buildings in the framework of climate change: An investigation across Europe. Sustainable Cities and Society, 60, 102213. https://doi.org/10.1016/j.scs.2020.102213

5.2: Community-level strategies for microclimate mitigation 101 Crawley, D. B., Pedersen, C. O., Lawrie, L. K., & Winkelmann, F. C. (2000). Energy plus: Energy simulation program. ASHRAE Journal, 42, 49–56. European Commission. (2018). Energy Performance of Buildings Directive. https:// energy.ec.europa.eu/topics/energy-efficiency/energy-efficient-buildings/energy-perfor mance-buildings-directive_en Fahmy, M., Mahmoud, S., Elwy, I., & Mahmoud, H. (2020). A review and insights for eleven years of urban microclimate research towards a new Egyptian era of low carbon, comfortable and energy-efficient housing typologies. Atmosphere, 11(3), 236. https://doi. org/10.3390/atmos11030236 Kim, S. W., & Brown, R. D. (2021). Urban heat island (UHI) variations within a city boundary: A systematic literature review. Renewable and Sustainable Energy Reviews, 148, 111256. https://doi.org/10.1016/j.rser.2021.111256 Li, D., Bou-Zeid, E., & Oppenheimer, M. (2014). The effectiveness of cool and green roofs as urban heat island mitigation strategies. Environmental Research Letters, 9, 055002. https://doi.org/10.1088/1748-9326/9/5/055002 Meteoblue. (2016). https://content.meteoblue.com/ Onishi, A., Cao, X., Ito, T., Shi, F., & Imura, H. (2010). Evaluating the potential for urban heat-island mitigation by greening parking lots. Urban Forestry and Urban Greening, 9(4), 323–332. https://doi.org/10.1016/j.ufug.2010.06.002 Piselli, C., Di Grazia, M., & Pisello, A. L. (2020). Combined effect of outdoor microclimate boundary conditions on air conditioning system’s efficiency and building energy demand in net zero energy settlements. Sustainability (Switzerland), 12(15), 6056. https://doi. org/10.3390/su12156056 Piselli, C., Salvadori, G., Diciotti, L., Fantozzi, F., & Pisello, A. L. (2021). Assessing users’ willingness-to-engagement towards net zero energy communities in Italy. Renewable and Sustainable Energy Reviews, 152, 111627. https://doi.org/10.1016/j.rser.2021.111627 Rizwan, A. M., Dennis, L. Y. C., & Liu, C. (2008). A review on the generation, determination and mitigation of urban heat island. Journal of Environmental Sciences, 20(1), 120–128. https://doi.org/10.1016/S1001-0742(08)60019-4 Romano, P., Prataviera, E., Carnieletto, L., Vivian, J., Zinzi, M., & Zarrella, A. (2021). Assessment of the urban heat island impact on building energy performance at district level with the EUReCA platform. Climate, 9(3), 48. https://doi.org/10.3390/cli9030048 Santamouris, M. (2014). On the energy impact of urban heat island and global warming on buildings. Energy and Buildings, 82, 100–113. https://doi.org/10.1016/j.enbuild. 2014.07.022 Ullah, K. R., Prodanovic, V., Pignatta, G., Deletic, A., & Santamouris, M. (2021). Technological advancements towards the net-zero energy communities: A review on 23 case studies around the globe. Solar Energy, 224(May), 1107–1126. https://doi.org/10.1016/j. solener.2021.06.056

6

Part 1: Cypriot case study Salvatore Carlucci, Ioanna Kyprianou, and Panayiotis Papadopoulos

1 Introduction The Cypriot case study is located at the Cyprus Institute (35.14 north and 33.38 east) in Aglantzia, a suburb at the southeastern edge of the city of Nicosia, the capital of the Republic of Cyprus. It is situated in a low-density area and borders the Athalassa National Forest Park. The climate in the area is a hot, semi-arid Mediterranean climate (Bsh according to the Köppen-Geiger climatic classification), with mild winters (average minimum ambient temperature about 10°C) and hot summers (maximum ambient temperature up to 46.7°C), resulting in a cooling-dominated climate. The Cypriot case study is the result of the application of the ZERO-PLUS design methodology to create a positive-energy settlement by designing a new theoretical prefabricated facility, the so-called ZERO-PLUS demohouse, intended for student housing, to be added to an existing prefabricated facility called “Air Quality Observatory” (AQO) hosting an office space and workshop at the ground floor and a climate and atmospheric laboratory at the first floor (Figure 6.1). The ZERO-PLUS demohouse has not been constructed yet, but a demonstration site in the area surrounding IQO has been identified as the venue of the Cyprus Institute for its future construction. The concept of the Cypriot case study is to create a positive-energy settlement formed by the AQO and the newer ZERO-PLUS demohouse by adopting, at the building level, high-performance passive building components, namely, the Fibran insulation, and a novel active system for space heating, ventilation, and air-conditioning (HVAC), namely, the FREESCOO HVAC system (Beccali et al., 2020; Finocchiaro et al., 2016), and installing, at the settlement level, highefficiency systems for the combined generation of electricity and heat from solar energy, namely, the IDEA’s HCPV/T system (Paredes et al., 2015). In 2020, the AQO was updated by adding one module of the IDEA’s HCPV/T and one FREESCOO HVAC system. The two systems were installed, commissioned, and monitored in operation, and facility users were surveyed to collect their feedback about the quality of the indoor environment through a post-occupancy evaluation questionnaire administered at periodic intervals during the monitoring DOI: 10.1201/9781003267171-8

6.1: Cypriot case study 103

Figure 6.1  Observatory (right). Table 6.1  Overview of the building parameters for the Cypriot case study General information Gross floor area in m Orientation of the building’s primary facade Stories Bedrooms Shading 2

Thermal properties U-values of walls (W m-2 K-1) U-values of roofs (W m-2 K-1) U-values of floors (W m-2 K-1) U-values of windows (glass + frame) (W m-2 K-1) g-value (adimentional) Infiltration rate (vol h-1)

Air Quality Observatory

ZERO-PLUS demohouse

130 South

390 South

2 0 None

2 3 Overhanging slab extension/ external shading in bedrooms

0.40 0.40 0.644 2.400

0.21 0.21 0.644 1.663

g = 0.7 1.0

g = 0.56 0.3

period.1 The FREESCOO HVAC system is mounted onto a fake wall filled with Fibran insulation. Regarding the ZERO-PLUS demohouse, it was designed using building performance simulation to explore a large number of different design alternatives evaluated against the three ZERO-PLUS objectives. Finally, a building variant including 40 mm of Fibran insulation on the perimeter walls and 80 mm on the roofs provided a suitable performance. The main parameters regarding the building and its technical features are reported in Table 6.1. 1 Unfortunately, the outbreak of the SARS-COVID-19 pandemic impacted accessibility to the facility and the period of administration of the questionnaires.

104  Salvatore Carlucci et al. 2 Objectives and methodology The ZERO-PLUS design and the measurement and verification methodologies were developed to support the design, construction, and operational validation of cost-competitive and energy-efficient settlements characterized by low greenhouse gas emissions in different climatic regions. The Cypriot case study faced the warmest climatic conditions and, combining theoretical and computational analysis on the ZERO-PLUS demohouse (Figure 6.1, left) and experimental procedures on the AQO (Figure 6.1, right), proved to meet the objectives of the ZERO-PLUS project. The feasibility of the ZERO-PLUS approach lies on four principal axes. 2.1  The structured transition from building level to settlement level

The methodology was developed by design to tackle the challenge of achieving cost-competitive and energy-efficient settlements characterized by low greenhouse gas emissions, not as a collection of individually optimized buildings, but as a network of grid-interacting and energy-efficient buildings, leveraging the opportunities offered by the larger settlement scale for installation of renewable energy generation systems. In Cyprus, there were no specific regulatory or legislative constraints hindering the transition from building-level to settlement-level design; however, up to 2021, there is no legislative landscape supporting the creation of energy communities or fostering the paradigm switch where buildings from energy consumers become energy prosumers. 2.2  C  alibrated energy simulation for accurate estimation of building performance

To estimate the energy performance of the existing buildings, as-built documentation and detailed site visits occurred to reduce specification uncertainty of AQO, and a verified and state-of-the-art energy simulation engine, EnergyPlus, was used to model and simulate both the AQO and the ZERO-PLUS demohouse. Following the instructions of the ASHRAE Guideline 14 (ANSI/ASHRAE, 2002), the energy model of the AQO was calibrated to properly represent the energy behavior of the facility before the amelioration and offer a trustworthy reference for evaluating the contributions of the newer insulation additions and the active HVAC system and the solar-powered renewable energy generation system. 2.3  A customized measurement and verification protocol

Complementary to a design support methodology for positive-energy settlements and compliant with international standards, a measurement and verification plan (M&VP) (Mavrigiannaki et al., 2019) was developed to supervise and assess the performance of the facilities against set targets and benchmarks throughout the entire construction and delivery process, from the installation and post-construction verification to the pre-occupancy and post-occupancy phases. The M&VP was explicitly tailored to the needs of a settlement rather than a building and resulted in

6.1: Cypriot case study 105 a fundamental tool for identifying deviations and design of fail-safe and mitigation measures, all the way guaranteeing the quality of the results. 2.4  The actual monitored performance and user satisfaction

The M&VP offered a consolidated guideline to monitor the actual performance of the facilities and the systems. Furthermore, post-occupancy evaluation (POE) surveys were created and administered to monitor the facility users’ responses and collect their feedback. The seamless integration of the M&VP, operational monitoring, and POE resulted in being a key aspect for the early detection of malfunctions and anomalies, which were promptly fixed by a rescue team appointed to supervise the case study. 3 The adopted technologies To conceive a positive-energy settlement, three technologies were adopted in the Cypriot case study: • Advanced insulation with the Fibran panels. • An innovative compact solar air-conditioning system, the FREESCOO HVAC system. • A pioneering high-concentration photovoltaic and thermal system, which uses a non-image optic system to concentrate the sunrays on actively cooled, multijoint photovoltaic cells, IDEA’s HCPV/T. These innovative technologies underwent two analyses. Life cycle cost analysis was utilized to determine the costs incurred by operating the energy and environmental systems chosen for the initial design of the settlements (Section 6). Energy performance and cost were optimized through iteration and progressive changes in the initial set of technologies. The technologies’ configuration eventually installed in the Cypriot settlements is summarized in Table 6.2.

Table 6.2  Overview of used technologies, their functions and expected performance Technology

Installation level

Function

Performance

Number of units

Fibran

Building

Energy conservation

6.8 kWh/(m2 year)

FREESCOO HVAC IDEA’s HCPV/T

Building

Energy conservation Energy production

14.8 kWh/(m2 year)

40 mm external walls 80 mm roof 1 system

Settlement

Electrical energy: 917.1 kWh/year Thermal energy: 1207.1 kWh/year

1 array with 20 concentrating mirrors

106  Salvatore Carlucci et al. Furthermore, these innovative energy conservation and renewable energy generation solutions are numerically tested for the ZERO-PLUS demohouse to reach the expected performance targets and provide insights for better integration of the technologies, enhancing the overall concept’s performance. The numerical analysis provided figures on implementing these solutions applied to the ZERO-PLUS demohouse evaluated in typical meteorological conditions. 3.1  Fibran insulation

The Fibran insulation is an extruded polystyrene (XPS) board made by extruding raw material mixture with the appropriate blowing agents and fire retardant. The extrusion makes the molecular structure of the XPS have almost 97% of closed shells. This provides XPS material with an extremely high resistivity toward water penetration. Furthermore, the coherence of the structure provides a board with very high compressive strength. The innovation in the XPS production is the creation of a waffle surface, which allows the best possible coherence and adherence between XPS and plaster or primer. The Fibran insulation also has a highly reflective coating that reduces space heating and cooling and overheating risk during the summer period. More specifically, the application of the Fibran technology to the ZERO-PLUS demohouse can conserve up to 2758 kWh/year, that is, about 7 kWh/(m2 year). 3.2  FREESCOO HVAC system

FREESCOO is a plug-and-play compact HVAC solution fed by low-grade thermal energy (e.g., solar thermal systems, heat pumps, gas boilers, or waste heat) that provides indoor thermal comfort. The system is based on a new solar desiccant evaporative cooling (DEC) concept, where solar heat and water are used to drive the cooling process that conditions the space the unit is connected to. The air handling process ensures temperature and humidity control and provides efficient air change thanks to a cross-flow heat exchanger. It is designed to satisfy the needs of the residential and small tertiary buildings. The energy input comes from a water–heat distribution loop that can be connected to a solar thermal plant or a gas-fired boiler as a backup energy source. The supply air is sent directly to the conditioned room, but air exchange with an outdoor space is also required. In the ZERO-PLUS project, the system design has been wholly revised to form a compact unit, which can be integrated into the building facade. One FREESCOO system has been installed in the Cypriot case study on the ground floor of the existing demobox (see Figure 6.2). The technical specifications of the FREESCOO HVAC system are shown in Table 6.3. The FREESCOO HVAC technology has a high energy efficiency ratio (EER) of 12.5 (SolarInvent, 2020), which provides a highly efficient generation of the required energy for space cooling.

6.1: Cypriot case study 107

Figure 6.2  FREESCOO system assembly location. Table 6.3  Technical specifications of the FREESCOO HVAC system Technical specifications

Remarks

Dimensions

1,986 mm × 1,000 mm × 283 mm (both evaporative and absorption units) Weight ~ 150 kg Kind of installation Wall-mounted Hot water Two pipes of 1/2” for The adsorption unit is directly supply connected to the circuit of solar and return hot water; a boiler can be used as a backup system. Cold water Two pipes of 1/2” for the The evaporative unit uses water evaporative unit and drain treated by a small osmosis system. Electrical characteristics 220 V AC or 24 V DC

3.3  IDEA’s HCPV/T system

The HCPV developed by IDEA, associated with ARCA Consortium, is a technology that exploits solar radiation to generate electricity and heat simultaneously, with high combined efficiency. A non-image optic system concentrates the sunrays on multifunction cells that are actively cooled on their backside. An array of 20 such receivers is integrated into a double-axis tracking system that precisely follows the sun’s position. To maximize the energy harvest of the IDEA’s HCPV system, the central axis must always be oriented in a north–south direction. The IDEA’S HCPV/T system exploits the property of optics (lenses or curved mirrors) to focus a wide area impacted by the sun’s radiation on a small area occupied by one or more high-efficiency photovoltaic cells (up to 44% of conversion rate) to generate electricity. The characteristics of this system are summarized in Table 6.4. In the Cypriot case study, one module of the IDEA’S HCPV/T system is

108  Salvatore Carlucci et al. Table 6.4  Characteristics of the IDEA’S HCPV/T system Technical specifications Net surface of each concentrator Solar concentration Optical efficiency Tracking system Dimension Weight Wind resistance Heating temperature Mirrors Structure

Remarks 2.025 cm2 ≈ 2.000 × 90% Two-axis Alt-Alt 1.4 × 6.5 m 280 Kg 3.4K N/m 60–70°C

At a wind speed of 20 m/s Compatible with the inlet of the Solarinvent FREESCOO HVAC system Ultraclean glass with Reflectivity >95% silver coating Galvanized steel

Figure 6.3  The IDEA’s HCPV/T developed by IDEA.

installed in front of the existing AQO, away from overshadowing from the neighboring property (Figure 6.3). Before installing the IDEA’S HCPV/T system, the ground in the proximity of the case study facility was prepared to host the structure safely and levelled it to avoid misalignment, which could affect its operation. Its installation requires positioning the center foot and installing the worm reduction gears, installing the side feet and the external axes, and installing additional components, such as the optic port, the transmission system, the actuation system, the optical concentrator, the heat sink, the hydraulic mounting connectors, the fitting sinks, and the rotary encoder. To ensure the functionality of the system, the mirrors required calibration. The IDEA’S HCPV technology generates electrical energy of 917.1 kWh per year, while it also generates 1,207.1 kWh thermal energy per year, which can be

6.1: Cypriot case study 109

Figure 6.4  Systems integration supporting the ZERO-PLUS demohouse: the IDEA’S HCPV/T produces electricity and heat used by the FREESCOO HVAC unit to provide ventilation, dehumidification, and space cooling and heating.

used by the FREESCOO HVAC technology or even to produce distilled water for various functions of the ZERO-PLUS demohouse. Finally, the FREESCOO HVAC and the IDEA’S HCPV/T technologies were connected electrically and hydronically so that the waste heat and electricity produced by the IDEA’S HCPV/T are used as input energy by the FREESCOO for space heating and cooling, respectively (Figure 6.4). 4 Building performance simulation The Cypriot case study simulations were carried out in both free-running and thermostatically controlled conditions using the dynamic energy simulation engine EnergyPlus, and its models were developed in the DesignBuilder interface. EnergyPlus was chosen because it is a versatile and thorough simulation environment for building performance. It provides several advanced opportunities for modeling HVAC, daylighting, airflow exchanges, cost, energy uses, and carbon emissions. In addition to assessing the energy-efficient technologies, it can also be used for determining building-level energy generation even if the available template and modeling classes are limited to components currently available in the market, and innovative and advanced systems like the IDEA’S HCPV/T and the FREESCOO HVAC cannot directly be modeled. These systems were modeled using average descriptive metrics, like generation efficiency and seasonal EER. EnergyPlus also enables calculating thermal comfort indices according to the standards ISO 7730 (ISO 2005), EN 16798-Part1 (CEN, 2019), and ASHRAE 55 (ANSI/ASHRAE, 2020), referring to the Fanger model and the European and ASHRAE adaptive models.

110  Salvatore Carlucci et al. 4.1  AQO: model calibration, validation, and energy breakdown

Calibration is a process where the results of a computer simulation are compared with measured data to improve the agreement of the simulation outcomes with respect to a chosen set of benchmarks through the adjustment of independent parameters implemented in the building model (Trucano et al., 2006). The simulation models of each case study, namely, “as-designed” models, have been updated according to the as-built drawings and considering the installed ZERO-PLUS advanced technologies. This first calibration of the models used, where possible, the data gathered during the pre-occupancy checks and preoccupancy monitoring, providing the “as-built” model and results. The final calibration of the models, aiming at evaluating and validating the AQO models, used all monitored data collected during the whole M&V period, which includes both the pre-occupancy and post-occupancy phases. For the Cypriot case study, the calibration of the numerical model of the existing AQO was conducted following the recommendations provided by the ASHRAE Guideline 14 (ANSI/ASHRAE, 2002) and summarized in the following six steps: 1. Producing a calibrated simulation plan. 2. Collecting data from the field. 3. Creating a numerical model of the building. 4. Comparing simulation model output to measured data. 5. Refining model until an acceptable calibration is achieved. 6. Reporting on observations. Calibrated simulation plan. First, the technical and analytical features required by the simulation task were specified, and EnergyPlus was identified as a suitable dynamic energy simulation engine. To create the geometry of the building model, the DesignBuilder interface to EnergyPlus was adopted. Next, a reliable temporal span on which to conduct the data collection and monitoring was set from the January 1, 2020, to the June 18, 2020. The first two months were considered as the stabilization period due to the installation and preliminary tests of the FREESCOO HVAC and IDEA’S HCPV/T. Furthermore, due to the COVID-19 lockdown and the inability of users to access the building, the period from March 1 to April 30 was used to drive the calibration, given the absence of the aleatory uncertainty due to user presence and interaction with building devices and openings. Then, the major sources of specification uncertainty were identified, and estimated variation ranges for each input variable were set. The different options were progressively tested, and the features of the resulting building variants are reported in Table 6.5. Data collection. This phase benefitted from all the information and data collected during the pre-installation analysis, installation and post-construction verifications, pre-occupancy and post-occupancy phases. A detailed and complete weather file was created using the software Elements from weather variables collected from a professional weather station available on the campus to reduce as much as possible the aleatory uncertainty related to climatic variation. The measured values were

6.1: Cypriot case study 111 Table 6.5  Input variables of simulation runs according to the calibrated simulation plan Sim. Air UU-value UU-value Type of no. change value floor value windows glass factor wall (W/m2K) roof (W/m2K) (W/m2K) (W/m2K)

Detailed Ground modeling temperof the ature entrance door

Operation mode

1 2 3 4 5 6 7 8 9

N N Y N Y Y Y Y Y

Free-running Free-running Free-running Free-running Free-running Free-running Free-running Free-running Heating in free-running, Cooling controlled (May–June)

1 1 1 1 1.5 1.5 1 1 1

0.8 0.8 0.8 0.4 1 1 0.8 0.8 0.8

0.4 0.4 0.4 0.4 0.5 0.5 0.5 0.65 0.67

0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.45

1.6 5.87 5.87 5.87 5.87 5.87 5.87 5.87 5.87

Double Single Single Single Single Single Single Single Simple

Fixed Fixed Fixed Fixed Fixed Dynamic Dynamic Dynamic Dynamic

outdoor dry bulb air temperature, relative humidity, atmospheric pressure, wind direction and speed, and global and direct solar radiation on a horizontal plane. Indoor environmental variables (i.e., air temperature, relative humidity, carbon dioxide level) were collected through the sensors installed in the AQO. Furthermore, the doors and windows states (open/close) were recorded. The transmittance of the building walls was measured with an in-field measurement campaign, and average minimum and maximum values were used during the calibration process. Creation of the numerical model of the building. The geometrical model of the AQO was based on the available as-built drawings. Preliminarily, the main dimensions reported in the as-built drawings were double-checked with on-site geometrical measurement. Next, the data collected in the pre-occupancy and postoccupancy phases were used to refine input variables in the numerical model. The zoning was set to reproduce the spatial layout of the AQO to better represent the thermal conditions inside the facility. To increase the case study representativeness, the model was calibrated by comparing the measured internal air temperature with the simulated one in the office room occupied by the users and located on the facility’s ground floor. All available information about passive and active systems available at the facility was filled in the simulation tool. Comparing simulation model output to measured data. Several simulations were conducted according to the calibrated simulation plan to identify the combination of input data that best replicates the indoor measured air temperature trend. Data relating to the measured internal temperature used for calibration were obtained through post-occupancy measurements with sub-hourly frequency (every quarter of an hour). Starting from these values, the hourly temperature was generated for the entire period indicated in the calibrated simulation plan. To evaluate the goodness-of-fit of each simulation run, two validation indices were calculated

112  Salvatore Carlucci et al. according to the ASHRAE Guideline 14 (ANSI/ASHRAE, 2002): the normalized mean bias error, NMBE, and the coefficient of variation of the root-mean-square error, CV(RMSE): n

( y - yˆ i ) NMBE = S i =1 i (n - p) ´ y

CV ( RMSE ) =

S( yi - yˆ i )2 n- p y

Where n represents the number of data points or periods in the baseline period, y represents measured values and yˆ the simulated ones, y represents the arithmetic mean of the sample of n observations, and p, which is equal to 1, represents the number of parameters or terms in the baseline model, as developed by a mathematical analysis of the baseline data. According to the ASHRAE Guideline 14, a model can be considered to have been calibrated if, for hourly values, NMBE is in the range of ±10% and CV(RMSE) is lower than 30%. Simulation no. 9 reaches an NMBE of +7.5 and a CV(RMSE) of 21.6%; hence, it can be considered calibrated according to the ASHRAE Guidelines 14. The calibrated model can reproduce the thermal behavior of the actual building in the considered period, although it may not meet the daily fluctuation of the monitored data on some days. Also, three spikes cannot be explained by the data, but they only appear at the beginning of the period and seem not to affect the other days of the period.

Figure 6.5 Validation of the AQO model with respect to measured total electric energy used by the facility.

6.1: Cypriot case study 113 Table 6.6 Energy performance of the Air Quality Observatory: simulated and measured data Energy use (kWh/m2/M&V period)

Simulated data

Actual performance

Space heating Cooling/ventilation Domestic hot water Lighting Appliances Regulated energy use1 Renewable energy2 Net-regulated energy3

0 3.09 – 0.03 8.69 11.81 N/A 11.81

0 N/A – N/A N/A 12.15 N/A 12.15

1

2

3

Heating, cooling, domestic hot water, fans, pumps, and ventilation (otherwise known as the building load). Energy production from building-integrated renewables and the energy produced by the community/ settlement systems. Regulated energy use minus renewable energy.

While the calibration period lasted from March 1 to April 30, 2020, the M&V period lasted from January 1 to July 30, 2020. Figure 6.5 shows bar charts comparing final calibrated simulation results and actual performance on a monthly basis for the M&V period. The figure depicts the total electric energy required by the AQO. The calibrated model is capable of reproducing quite well the monitored data. Estimated from the calibrated model, Table 6.6 shows the disaggregation of energy uses of the facility for the M&V period. Note that space heating is zero because the heating system was not used as the facility was not occupied during the winter. 4.2   ZERO-PLUS demohouse: energy breakdown

ZERO-PLUS demohouse was modeled in DesignBuilder and simulated in EnergyPlus using the same assumptions adopted for the AQO model. Since the ZERO-PLUS demohouse was not built before the M&V period, it was not possible to measure its actual energy consumption disaggregated per energy use. Table 6.7 shows the results of the energy simulation of the ZERO-PLUS demohouse. The concept of the Cypriot case study is to create a positive-energy settlement formed by two ZERO-PLUS demohouses built at the Cyprus Institute premises and connected to two IDEA’S HCPV/T modules with 20 mirrors each. The performance of this settlement will be indicated “as-designed” and refers to the results of the dynamic energy simulation. Given the theoretical nature of the task, it is not possible to compare the as-built performance with the “actual” performance of the settlement.

114

Salvatore Carlucci et al. Table 6.7 Energy performance of the ZERO-PLUS demohouse Energy use (kWh/m2/M&V period)

Simulated data

Space heating Cooling/ventilation Domestic hot water Lighting Appliances Regulated energy use1 Renewable energy2 Net-regulated energy3

41.51 29.64 2.05 19.72 45.11 73.20 54.29 18.91

1

2

3

Heating, cooling, domestic hot water, fans, pumps, and ventilation (otherwise known as the building load). Energy production from building-integrated renewables and the energy produced by the community/settlement systems. Regulated energy use minus renewable energy.

5 The transition from individual buildings to the settlement Greater energy efficiency can be achieved through a transition from individual buildings to a grid-interconnected settlement, in which the energy loads and resources are optimally managed. The demand for energy in an individual building can fluctuate over the day, with peaks at different times determined by performed activities. When aggregated over a settlement, the peaks can smoothen out when accounting for the cumulated energy demand of a community. This aggregation assessment can be done for the whole year and/or seasonally to identify which season is characterized by higher energy demand. The Cypriot case study settlement was studied aggregating the facilities’ energy consumptions and the renewable energy generation, assuming ideal energy storage available at the settlement level. For this reason, the numerical models of the two ZERO-PLUS demohouses were used. The transition from the building level to the settlement was simulated by modeling an energy management system that takes full advantage of the renewable energy production of the installed technologies against the existing energy consumption patterns of the buildings, preferring to use the yielded renewable energy first to increase the settlement’s self-consumption, and then storing any residual energy for deferral use. 5.1   Base case

The two ZERO-PLUS demohouses are student houses assumed to be primarily used during the lunch breaks and after the course time in the afternoon and evening during the workday and have a complete occupation during the weekends. At the settlement level, two IDEA’S HCPV/T units with 20 mirrors each are considered to generate electricity and waste heat, both available to meet the needs of

6.1: Cypriot case study 115

Figure 6.6 Hourly average energy balance between consumption, generation, and storage. Left: January. Right: July.

the settlement. However, in the analysis, only the electrical yield of the IDEA’S HCPV/T units is considered and not its heat generation. The electricity produced by the IDEA’s HCPV/T at settlement level is firstly self-consumed, and in case of production surplus, it is assumed to be stored in ideal batteries and used to offset the facility’s peak demand. To characterize the electricity generation and demand, the average day for the months of January and July is considered. January is chosen because it is the coldest month, and July is selected because it is the hottest month, if we exclude August, when students typically leave the Institute for their summer holidays. The electricity demand of the settlement fluctuates over the day, with peaks in the morning (between 08:00 and 10:00 in winter and 07:00 and 9:00 in summer) and the evening (between 20:00 and 23:00). The total hourly electricity consumption and production of the settlement, averaged over January and July (Figure 6.6), show that most of the renewable energy is generated during the central hours of the day but only partially is directly self-consumed by the two buildings. Furthermore, only two modules of IDEA’S HCPV/T are not sufficient to cover the daily electricity demand of the settlement. 5.2  Optimization

Assuming to install six IDEA’S HCPV/T units and storage with a max battery discharge potential of 3.5 kW, it is possible to fully cover the electricity demand of the settlement during the summer months, but a limited contribution is required from the grid in the winter months (4.10 kWh/day). 6 Environmental impact The ZERO-PLUS settlement in Cyprus is a theoretical cluster made of two demohouses located into the plot of the Cyprus Institute along the east–west axis (therefore, not generating solar obstructions among them) and two IDEA’s HCPV/T

116  Salvatore Carlucci et al. Table 6.8 Consumption, generation, and self-consumption statistics related to the Cypriot case study settlement Cy settlement

Daily average electricity

January

July

IDEA’S HCPV/T units: 6 kWp Battery size: 12 kWh 7 kW peak/3.5 kW continuous Efficiency: 90%

Total consumption (kWh) Total generation (kWh) PV electricity consumed instantly Self-consumption from PV alone (percentage of PV electricity consumed instantly) PV electricity discharged from the battery (kWh)

666.5 539.4 230.6 42.7%

895.9 1116 377.6 33.8%

181.4

738.4

Table 6.9 Summary of energy conservation and cost savings for the Cypriot ZERO-PLUS settlement Total area of Energy demonstration consumption (m2) for the reference demohouse + districts (kWh)

Energy consumption of the ZERO-PLUS demohouse and settlements (kWh)

Energy conservation on a yearly basis (kWh)

Carbon emissions reduction (ton CO2/ year)

Energy cost savings (€/year)

2 × 130

13,976 (PE = 21,500)

5,393 (PE = 14,066)

4.37

1,681.40

19,369 (PE = 35,813)

Note: The numbers in parentheses are the primary energy consumption based on the fuel mix used.

modules situated in front of the demohouses. To compute the carbon emission reduction from the energy calculation reported in Kyprianou and Georgiou (2019), the following carbon emission conversion factors are adopted: 0.794 kgCO2/kWh for electricity and 0.266 kgCO2/kWh for diesel. Given an electricity savings of 2,696 kWh and a diesel saving of 164 kWh (both delivered energy per energy carrier) for each ZERO-PLUS demohouse, the corresponding carbon emission reduction of the settlement is 0.034 tonCO2/m2/year. Moreover, the overall yearly energy cost saving for the ZERO-PLUS settlement can be computed assuming a specific energy cost saving of 0.3 €/kWh for electricity2 and 0.638 €/liter for (heating) diesel.3 Furthermore, taking, on average, a calorific content of diesel of 10.96 kWh/liter (whose only 30% is directly used for water heating4), the specific energy cost saving is 1,681.40 €/year. 2 https://in-cyprus.philenews.com/cyprus-had-the-highest-increase-in-electricity-prices-in-theeu/#:~:text=According%20to%20Eurostat%2C%20electricity%20prices,%E2%82%AC18.3%20 per%20100%20kWh 3 www.globalpetrolprices.com/Cyprus/heating_oil_prices/ 4 www.sustainabilityexchange.ac.uk/files/cambridge_regional_college_sus_how_much_energy_do_ you_use_pdf.pdf

6.1: Cypriot case study 117 Table 6.10  KPIs for the Cypriot case study #

ZERO-PLUS KPIs

As-designed

Check

1

Net-regulated energy usage (kWh m-2 year-1) (Target: < 20 kWh m-2 year-1) Renewable production (kWh m-2 year-1) (Target: > 50 kWh m-2 year-1) Cost reduction (%) (Target: 16% reduction compared to the reference case) Carbon emission reduction (kgCO2 m-2 year-1) (Target: > 34 kgCO2 m-2 year-1)* Self-consumption ratio

14.8

OK

55.4

OK

17%

OK

33.60

Within uncertainty range

2 3 4 5

33.8% in July 42.7% in January

Carbon emissions reduction target is relative to the Cypriot case study. It is based on the reduction targeted during the project’s design phase.

*

The cost reduction is calculated as the yearly energy cost saving of the ZEROPLUS settlement with respect to a similar settlement made of a conventional demohouse (Kyprianou & Georgiou, 2019). 7 Cost assessment The third KPI of the ZERO-PLUS project regarded a reduction of the investment cost of the ZERO-PLUS demohouses to be reduced by at least 16%, compared to a regular net-zero energy building. A life cycle cost analysis was performed, and summary tables are reported in Appendix 1. 8 Conclusions The theoretical settlement composed of the two ZERO-PLUS demohouses and two IDEA’S HCPV/T underwent detailed energy, emission, and cost analyses, reported in Section 5.1.1, of the deliverable D7.7 of the ZERO-PLUS project. Table 6.10 reports the performance metrics of the Cypriot case study settlement and shows that the Cyprus ZERO-PLUS settlement succeeded in meeting the objectives of the ZERO-PLUS project. The carbon emission reduction was estimated to be slightly lower than the reference target, but it falls in what can be assumed to be the uncertainty range. References ANSI/ASHRAE. (2002). ASHRAE Guideline 14–2002 Measurement of Energy and Demand Savings. ASHRAE Inc., American Society of Heating, Refrigerating and AirConditioning Engineers (ASHRAE). ANSI/ASHRAE. (2020). ANSI/ASHRAE Standard 55–2020: Thermal Environmental Conditions for Human Occupancy. ASHRAE Inc., American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

118  Salvatore Carlucci et al. Beccali, M., Scoccia, R., Finocchiaro, P., Zanetti, E., & Motta, M. (2020). FREESCOO facade 3.0, a compact DEC thermally driven air-conditioning system for apartments. Proceedings of the ISES Solar World Congress 2019 and IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2019. https://doi.org/10.18086/ swc.2019.55.02 CEN. (2019). EN 16798–1:2019 – Energy Performance of Buildings – Ventilation for Buildings – Part 1: Indoor Environmental Input Parameters for Design and Assessment of Energy Performance of Buildings Addressing Indoor Air Quality, Thermal Environment, Lighting and Acoustics. Comite Europeen de Normalisation (CEN). www.en-standard.eu/ bs-en-16798-1-2019-energy-performance-of-buildings-ventilation-for-buildings-indoorenvironmental-input-parameters-for-design-and-assessment-of-energy-performance-ofbuildings-addressing-indoor-air-quality-thermal-environment-li Finocchiaro, P., Beccali, M., Brano, V. L., & Gentile, V. (2016). Monitoring results and energy performances evaluation of Freescoo solar DEC systems. Energy Procedia. https://doi.org/10.1016/j.egypro.2016.06.240 ISO. (2005). ISO 7730:2005 – Ergonomics of the Thermal Environment – Analytical Determination and Interpretation of Thermal Comfort Using Calculation of the PMV and PPD Indices and Local Thermal Comfort Criteria. Geneva, Switzerland: International Organization for Standardization (ISO). Kyprianou, M., & Georgiou, G. (2019). Impacts Calculation and Methodology for Simulations and Performance Verifications for the ZERO-PLUS Demohouse in Cyprus. Nicosia, Cyprus. Mavrigiannaki, A., Gobakis, K., Kolokotsa, D., Saliari, M., Laskari, M., & Assimakopoulos, M. N. (2019). Measurement and Verification Plan for NZE Settlements. ZERO-PLUS. Athens. Paredes, F., Montagnino, F. M., Salinari, P., Bonsignore, G., Milone, S., Agnello, S., Barbera, M., Gelardi, F. M., Sciortino, L., Collura, A., & Lo Cicero, U. (2015). Combined heat and power generation with an HCPV system at 2000 suns. AIP Conference Proceedings. https://doi.org/10.1063/1.4931550 SolarInvent. (2020). Unità Di Trattamento Dell’aria FREESCOO 3.0V – Manuale Di Installazione Uso e Manutenzione. Catania: SolarInvent. Trucano, T. G., Swiler, L. P., Igusa, T., Oberkampf, W. L., & Pilch, M. (2006). Calibration, validation, and sensitivity analysis: What’s what. Reliability Engineering and System Safety. https://doi.org/10.1016/j.ress.2005.11.031

6

Part 2: Production and installation planning Wen Pan and Shabtai Isaac

1 Introduction To reduce the cost and duration of the process of constructing NZE communities and increase the quality of the outcome, the design of the buildings and systems in the community must be linked with off-site production and on-site installation considerations. This chapter accordingly describes an integrated and collaborative approach for planning and managing the three main processes of design, production, and on-site assembly. The Cyprus case study (Chapter 6.1) and the Freescoo HVAC system that was installed in it (for further details, see Chapter 8.3) are used as an example to describe the proposed approach. In the ZERO-PLUS project, the focus of production and installation planning was on applications of off-site manufacturing for the integrated building facade systems that were used. The goal was for the off-site manufacturing strategy to minimize the embedded energy consumed during the production and assembly processes and increase value-added activities. The planning method that was developed for this goal was based on the “design for X” (design for production, assembly, etc.) approach. The HVAC system is chosen to demonstrate the potential of the proposed approach for the integration of buildings and energy-related products and systems in the NZE community. The HVAC system requires an additional frame system to accommodate the product and connect to the building. For this purpose, an interface between the product and the building is required. Alternative solutions were collaboratively developed for the integrated frame systems, based on the notion of design for manufacture and assembly. Each design demonstrated an alternative mode of production and assembly sequence and was analyzed during the production phase to evaluate its advantages and disadvantages. The collaborative definition of optimal solutions for the design, production, and assembly of the system required a systematic analysis by all parties involved of the system’s requirements. This was supported by a process-oriented planning methodology that allowed seamless information-sharing. Frequent exchange of information helped identify issues in advance, predict malfunction, reduce production time, and influence production cost.

DOI: 10.1201/9781003267171-9

120  Wen Pan and Shabtai Isaac While the specific example in this chapter focuses on the integration of energy technologies at the building level, the proposed planning approach can be extended from the building envelope to the whole settlement and consider the application of technologies at the community level. When integrating components and technologies into the building or settlement level, the integrated technology product design must be feasible, flexible, modular, and customizable to facilitate the interconnection of the various sub-systems at the building or settlement level in an aesthetic and ergonomic way. The design also needs to consider the life cycle planning aspects in the early design stage to ensure the optimal performance of the energy-related systems, the maximal potential cost savings, and the most value-adding activities throughout the entire project phase. 2 Objectives and challenges The key objectives of the planning method include: 1. Assisting the technology providers in improving or customizing the selected products for the buildings, in which their technology shall be implemented. 2. Collaborating effectively with the case study owners, architects, and engineers to communicate the specifications of the technology products to be installed. 3. Assisting in the preparation of the design documents that must be submitted to the local authority. 4. Suggesting feasible solutions to ease on-site assembly and future maintenance. In addition, a feasibility study was conducted of how to potentially implement robotics and automation technology in the manufacturing and assembly phases of the selected technology products. One of the most challenging tasks for the project team over the course of the project is to ensure sufficient information exchange among the different project partners. This is due to the multidisciplinary nature of the project team and a lack of specialization in each other’s professional fields, which leads to some of the involved partners not being familiar with each other’s expertise and experience. Such challenges may potentially lead to miscommunication between the engineers and the architects, ultimately resulting in delays. This was also the case in the ZERO-PLUS project, where most of the technology providers were small start-up companies that were unable to employ additional employees to bridge the communication gap between the company and its clients. Most of the technologies were highly innovative. From the architect’s point of view, the technology products were relatively new, and the specifications and detailed installation manuals not available. Therefore, it was extremely difficult for the architects to incorporate the correct details into the design that had to be submitted for the building permit application and the building regulation application. The proposed approach can help support communication between technology providers, case study partners, and other stakeholders during the production and installation planning phase. The existing design can be improved based on the

6.2: Production and installation planning 121 requirements defined by the technology provider, and tailored solutions can be provided according to the special circumstances of each project. Through improved communication and teamwork, the planning approach can: • Propose feasible solutions for (a) production, (b) transportation, (c) assembly, (d) installation activities, (e) life cycle management (where feasible). • Ease the production, assembly, installation procedures for each product. The planning method aims to increase productivity, value-added activities, and consequently, time and cost savings. • Reinforce the communication between the technology providers and other stakeholders – architects, project managers, project owners, engineers, and key subcontractors. To ensure smooth information exchange, it is necessary to build up a mutual understanding of the project among all the stakeholders. The challenge for the different stakeholders to jointly make decisions throughout the process is often further increased due to some of the work tasks changing in scope over time. Similarly, some of the technology products may evolve. Furthermore, as the project proceeds, the technology providers may have changing interests. 3 The planning method applied for the Freescoo HVAC system Freescoo is an innovative, compact solar air-conditioning system developed within the ZERO-PLUS project. It is designed for ventilation, cooling, de-humidification, and heating of buildings in the residential and tertiary sectors. Solar heat and water are used to drive the cooling process that conditions the space the unit is connected to. The air handling process ensures temperature and humidity control. In addition, the system is designed to provide air flow in the conditioned space. The supply air is sent directly to the conditioned room, but air exchange with an outdoor space is also required. In the ZERO-PLUS project, the Freescoo HVAC system design had been completely revised to form a compact unit which can be integrated into the building facade. In the Cyprus case study, the HVAC technology was installed and integrated with the building envelope. The HVAC technology is a free-standing system that cannot connect to the building envelope directly without an additional frame system. As such, the HVAC requires a frame system that can be prefabricated as an integrated facade system, which can then be further integrated into the building. After discussions with SolarInvent, the design goals for the frame system were defined as follows: • Minimized amount of parts • Flexible, interchangeable, and upgradable • Lightweight • Easy to assemble by either human workers or robots during production and onsite construction • Suitable for mass production

122  Wen Pan and Shabtai Isaac In line with these goals, the frame system was designed to allow future expansion and upgrades. Furthermore, other types of energy products could potentially also be fitted and replaced when necessary. The proposed planning method was applied for the design of the frame system, in four steps. The first step consists of an initial proposal. This proposal includes the development of: a. Alternative initial designs for the system b. Initial design of an off-site manufacturing facility c. Initial on-site installation methods The second step consists of an updated design, prepared through an application of the proposed assembly and installation processes using a life-size mock-up. The third step consists of a collaborative and iterative improvement of the design, assembly, and installation plans for the specific case study. The fourth and final step consists of the supervised on-site installation of the final product. 4 Initial proposal for the integrated frame system 4.1  Alternative initial designs

The initial step in the method included the proposal and evaluation of three alternative designs for the integrated frame system. The proposed frames were all planned to be made of structural steel profiles fabricated by a subcontractor. The first design consisted of 20 parts (Figure 6.7) divided into four key categories (left and right channel parts, the front and rear channel parts, a top fix channel, and a fix channel part). These parts were to be connected to each other with nuts and bolts, and the channel parts positioned in a top-down sequence that would allow the assembly to be easily carried out by an assembly robot. Two other alternative designs were similarly developed.

Figure 6.7  First alternative design for the proposed integrated frame system.

6.2: Production and installation planning 123 4.2  Initial design of an off-site manufacturing facility

The initial step in the method also included a feasibility study that evaluated how to potentially implement robotics and automation technology in an off-site manufacturing (OSM) facility for the manufacturing and assembly phases of the system. A dedicated production and assembly analysis method known as assembly evaluation method was applied for this. A different alternative strategy and corresponding OSM facility design were developed for each of the three initial designs that had been proposed. Thus, the first alternative consisted of six sections, including a material feeding cell, an assembly cell, assembly station A, assembly station B, a packaging station, and a shipping station (Figure 6.8). The integrated robotic cell concepts were incorporated into the assembly-line design. A similar approach was also used for the two other alternatives, in which the different types of frames could be produced. 4.3  Initial on-site installation methods

Following consultations between the project team members, including the case study owner and the architects, three different installation methods were proposed. These were developed as initial proposals, which would later need to be reassessed based on project-specific aspects, such as the structural details of the wall, the connection methods, the accessibility of the site, etc. The first alternative installation method (Figure 6.9A) featured a frame system that was completely embedded into the wall along with the HVAC technology. This method gave a neat interior finish as the system and the frame appear in line with the internal wall. The only drawback was that it is difficult to assemble and maintain due to narrow gaps between the elements. In addition, this method requires

Figure 6.8  Proposed alternative designs for an OSM facility.

124  Wen Pan and Shabtai Isaac

Figure 6.9  Proposed on-site assembly sequences of the integrated frame with HVAC system.

an assessment of the energy performance of the building. In the second alternative (Figure 6.9B), the frame and the HVAC technology were half-embedded into the wall. The advantage of this method was the ease of assembly and maintenance. The third option (not shown here) included both the frame and the HVAC system being connected to the external wall. This method had minimal impact on the stability and energy performance of the building. However, because the system will be exposed to the external environment, an additional set of covering panels was needed to protect the system. 5 Updated design using a mock-up The HVAC system evolved over time, and different changes were made in its design after the initial proposals described in the previous section. The biggest change was that it now consisted of two separate modules – an evaporative (EVA) module and an adsorption (ADS) module – that would be assembled prior to onsite installation. Furthermore, the overall size of the system had increased, and noticeable changes were made in the top surface of the system. The top edges of both modules now had elevated sections, and the design and purpose of the installation frame consequently had to change.

6.2: Production and installation planning 125 To further develop the design, production, and installation plans of the frame system, and to avoid time delays that would occur if it waited for a fully functional prototype of the HVAC system to be produced and delivered, the project team decided to use a mock-up of the HVAC system that consisted of an empty casing, which was not functional yet included all the crucial features that would influence the on-site assembly process. The original design had allowed an installation frame to be built around the whole HVAC system so that it would be delivered with the frame as a modular facade kit system and could be slid into the assembly position. Now, several issues had to be considered. First, as mentioned earlier, the height of the system had increased, and this had to be coordinated with the height of the windows in a residential building. Second, the system was hard to handle and did not have any built-in handles or grips that could assist lifting and installation. Third, it would be very difficult to slide the system into position without dragging it on the building’s floor surface, and this could cause unnecessary damage to the floor finish. Taking these issues into consideration, a new installation frame concept was designed and tested in the lab using the mock-up to assist in the lifting, transfer, positioning, and fixing of the system in the correct assembly position. With the new design, the HVAC system could be easily jacked up and slid into position, with the need of only two people with basic hand tools for the entire installation task. A wooden wall structure was built in the lab and used to simulate the real structural wall in the testing of the installation using the mock-up. Following the development of the new design and the testing of its on-site assembly and installation, several recommendations were made. Thus, it was recommended that the height of the HVAC system should not exceed 1,000 mm, and a specific installation sequence was recommended to avoid damaging the floor or causing obstructions during the construction phase, during the final installation of the system. 6 Iterative improvement of the design, assembly, and installation plans At this stage, the generic plans for the design, assembly, and installation of the frame system had to be adjusted while considering the specific local conditions in the Cyprus case study. This was done through an iterative process that included seven revisions until the final design was reached and on-site installation could commence. This was also a collaborative process that involved frequent communication between different project partners. To ensure that this collaborative process would be carried out smoothly and on time, the roles and responsibilities of each of the involved parties were clearly defined, and the work was scheduled according to four stages of concept development, initial and detailed design, design optimization, and on-site installation. The HVAC system continuously evolved over time (Figure 6.10). Its design changed from two separate modules (the EVA module and the ADS module) to a compact single-unit design with a height of 1,986 mm. Given the large vertical space that the HVAC system would take up, the original plan to fully integrate it

126  Wen Pan and Shabtai Isaac

Figure 6.10  Design evolution of the Freescoo system.

with the building envelope was no longer feasible. To avoid significant alteration works, the external installation method was adopted instead. The technology provider had identified four key functional requirements for the installation method: 1. The method should ease the installation task. 2. The design should offer protection against external elements, such as rain and wind. 3. The design should offer an elegant appearance. 4. It should facilitate necessary maintenance tasks. An initial design was prepared as a proof of concept. It presented a free-standing steel installation frame that supports the weight of the system, the top overhanging section provides weather protection, and the access door that is secured by conventional padlock allows the maintenance work to be carried out easily. This prototype was presented to the technology provider for feedback. In the second iteration, a small in situ concrete footing was proposed. The frame could be lifted by a handheld forklift to ease its installation. Following this, discussion ensued with the technology provider on further design improvements. Ideas were exchanged on a fully integrated approach, and the decision was made to use an installation wall that would provide the appearance of a system fully integrated with the building envelope. The third design featured the installation wall, which was not load-bearing, the weight of the Freescoo system being instead supported by the steel installation frame (Figure 6.11). The installation wall consisted of a wooden stud wall that contained the frame and the HVAC unit, as well as insulation. Similar to the previous design, this approach was also equipped with an access door for maintenance purposes.

6.2: Production and installation planning 127

Figure 6.11  The third version of the external installation method.

The third version received positive feedback from the technology provider. A coordinated site survey also provided some valuable insights on the site conditions. Three further revisions of the design included adjustments in the design of the installation wall (so that it covered a larger part of the facade, providing a unified appearance), a replacement of the steel installation frame and the wooden stud back support structure with a galvanized strut channel, and the use of cladding wall panels instead of plasterboard. Three such panels located were to be used as maintenance doors that can be opened individually, which eases inspection tasks. The final design was a simplified version of the previous designs, which reduced the types of materials used for the installation, which consequently speeded up procurement and logistics procedures (Figure 6.12). The final installation procedure consisted of five steps (Figure 6.13): • Remove the ground floor window, making an opening below the window opening for ventilation grills. • Install galvanized strut channels. • Install HVAC system and the fixture profiles. • Install insulation panels. • Install cladding wall panels.

128  Wen Pan and Shabtai Isaac

Figure 6.12  The final design of the Freescoo system installation method.

Figure 6.13  The proposed installation procedure.

7 Supervised on-site installation of final product To ensure that the on-site installation would run smoothly, the project partners prepared a comprehensive installation plan. The relevant partners traveled to the Cyprus case study site to guide, assist, and collaborate with the local team and carry out necessary installation tasks on-site. Prior to the commencement of the on-site installation, the following tasks were carried out: • Preparation of the site for installation • Confirmation of the availability of the local contractor

6.2: Production and installation planning 129 • Confirmation of the availability of required installation materials (insulation, galvanized strut channels, and other accessories) • Confirmation that the design documents are distributed to the right party • Ensuring that the technology products are produced and delivered on time The installation was successful. Most of the prefabricated parts and components (shipped from Italy) were fitted perfectly or with very little deviation. The HVAC system was relatively heavy for manual handling, and it was therefore recommended that in the future a mini crane would be used on-site for the lifting of the system, and that hoist brackets be installed on the system casing to assist in the lifting. 8 Conclusions This chapter describes the process of integrating different technologies in a project. The technology products are analyzed, evaluated, and optimized in terms of product design, assembly, and life cycle management. A planning method was introduced that supports such an analysis in several structured steps. Its application was demonstrated in the case of the installation of the Freescoo HVAC system. In the first step, three alternative designs were proposed for the integrated frame system that would support the HVAC system, as well as three corresponding conceptual designs for the off-site manufacturing facility. In addition, three on-site installation methods were presented. Next, a mock-up construction was used in a lab to test the assembly sequence, to evaluate the appropriate installation sequence, and to suggest changes that would improve assembly speed and operational safety. Following this, the design of the system was iteratively improved to facilitate the requirements of the technology provider, as well as the project owner. The successful completion of the on-site installation process demonstrates the utility of the proposed planning method, in supporting the definition of an optimal installation strategy.

7

Part 1: French case study Shabtai Isaac

1 Introduction The town of Voreppe is located in an urban area with medium-density housing in the eastern part of France, about 15 km northwest of Grenoble City. Voreppe is a city of 10,000 inhabitants and is located in a lowland between two mountains with a variable wind direction. The ZERO-PLUS building has been constructed 200 m away from the railway station linked to Grenoble (10 minutes) as well as to the cities located between Voreppe and Lyon. The climate in this area is continental, with a temperature gradient that can range from −11°C in the winter season and up to +36°C in the summer season. The rainfall is on average around 1,000 mm per year. The ZERO-PLUS building is a collective building with 18 apartments on four floors. It includes seven one-bedroom, six two-bedroom, four three-bedroom, and one four-bedroom apartments. The objectives of the city and Alpes Isère Habitat focus on the urban development around the railway station. More precisely, two buildings (including the one of ZERO-PLUS) comprising 18 and about 14 social housing units will be constructed, and a building of roughly 20 dwellings for sale will complete this new settlement. So far, only the ZERO-PLUS building has been constructed and occupied (Figure 7.1). The French case study pioneered the national thermal regulation for 2020 to generate savings for tenants thanks to energy autonomy. New French buildings must meet requirements of the 2012 Thermal Regulation (RT2012) and have an energy consumption lower than 75 kWh/m²/year (primary energy) for heating, domestic hot water (DHW), cooling, and electricity for common equipment (fans, pumps, etc.). The case study was, however, built to meet the new French BEPOS standard (Bâtiment à Energie POSitive, or positive-energy building), which includes goals regarding energy consumption and embodied energy. Consumption must be lower than 40 kWh/m² and must be offset with on-site energy production. Air leakage (Q4pa-surf) must be lower than 0.4 m3/h/ m². Energy needs for materials (embodied energy) must be calculated using a methodology complying the NF EN 15978 norm. Finally, to ensure that these goals are achieved, stakeholders must have access to the actual energy performance.

DOI: 10.1201/9781003267171-10

7.1: French case study 131

Figure 7.1  French case study.

2 Selection of technologies A combination of technologies was selected to meet the energy performance goals, with the help of dynamic thermal simulation. The thermal resistance and thickness of the insulation of the building’s envelope (walls and glazing) were defined in accordance with the thermal regulation. The building is connected to Voreppe’s urban heating network, which is supplied by renewable energy at a rate higher than 87%. Most of this energy is produced by a wood biomass boiler plant. The connection of the building to the urban heating network was a condition for the municipality to sell the land for the project. A heat exchanger of the biomass urban heating network is used to provide heat (hot water) to the building. The heat exchanger is able to deliver approximately 44,000 kWh per year (heating and hot water) and is connected to the building’s 750 L DHW tank to supplement the production of hot water. To achieve positive energy performance, the remaining energy consumption of the building is offset through solar energy generation. Firstly, 20 dual-technology solar modules, which provide both thermal and photovoltaic energy, were installed on the rooftop of the building (Figure 7.2). These modules are manufactured by DualSun and exploit solar radiation to simultaneously generate electricity and heat. The building’s DHW boiler is powered with the solar modules and further supplemented from the urban heating network when needed. Each module has the dimensions of a standard photovoltaic panel. It is made of high-efficiency monocrystalline cells and cooled by water circulation on the backside of the panel. An ultra-thin heat exchanger is integrated into the panel, generating an excellent heat transfer between the photovoltaic front side and water circulation on the backside. The nominal PV power of each module is 310 Wp, and the thermal power

132  Shabtai Isaac

Figure 7.2  Dual-technology solar modules.

Figure 7.3  Smart roof edge solar energy system.

output is 570 W/m². The 20 solar modules provide approximately 7,800 kWh/year in electricity, and 8,288 kWh/year of warm water. A second type of solar energy system installed in the building was developed for this project by ANERDGY. This is a modular all-in-one smart roof edge system which is flexible in terms of the number of units, energy generation, design option, and functions (Figure 7.3). It combines the following key features of energy, design, and function: • Energy. The modules exploit solar radiation to generate electricity, thanks to a standard photovoltaic panel implemented on an innovative base frame. They are dimensioned for a photovoltaic electrical production of approximately 6,540 kWh/year.

7.1: French case study 133 • Design. The modules are structurally integrated in the building. This offers new visual silhouettes and multiple design options in terms of coloring, illumination, or facade design. In addition, the roof edge positioning of the system opened up the inner area of the roof for the installation of the DualSun modules. • Function. The system comes with a base frame to host the modules. This frame, together with the module, integrates building functions such as lightning protection, safety rail, snow, rain and ice handling, facade water protection, and hosting space for technical roof installations. In the French case study, a total of six modules has been installed. 3 Cost and energy performance The cost and energy performance of the French case study resulted in: • A reduction of 18.4% in the construction cost when compared with an NZE reference building. • A 16 kWh/m2/year net-regulated energy consumption. • 55.8 kWh/m2/year energy production by the Renewable Energy Systems (RES). Since this is a social housing project, tenants pay a limited rent (calculated according to the grants received at national and local level). This means that the rent doesn’t include all the construction costs. Nevertheless, the energy costs are fully paid by the tenants, and they therefore directly benefit from the building’s improved energy performance and lower energy costs. The energy cost reduction for this case study can be estimated to be: • 3.9 €/m² due to the reduction in required heating (15 + 8 kWh/m² compared to 45 + 18 kWh/m²) and energy cost (of the district heating system). • 0.7 €/m² due to the reduction in electricity consumption. • 3.5 €/m² due to the production of 10 kWh/m² of PV electricity. 4 Changes that occurred in the project Several changes occurred in the requirements and design of the building during the project. These changes required coordination among multiple stakeholders and dynamic project management. The plan to use building-integrated PV modules in the facade was abandoned when the start-up company that was to provide the technology suspended its activities. Another plan was to install a combined wind and solar energy generation system. However, the construction of the building had already started when plans for a future development next to the building were announced. The position of this development in relation to the building would have a major impact on the wind flow patterns on the rooftop. In effect, the installation of the wind turbines had to be cancelled and all the energy had to be produced by solar energy technology instead.

134  Shabtai Isaac Furthermore, the implementation of a planned concentrated photovoltaic (CPV) system was prevented due to the lack of an appropriate interface (inverter) with the local grid. The French electricity grid is three-phase, while the CPV technology had a monophase inverter. The technology provider made an extensive market research, but an appropriate inverter that would offer the required flexibility in connecting the CPV modules to each of the three phases was not found. As a result, the installation of the CPV in France had to be cancelled. It is worth noting that this challenge revealed an opportunity for the technology provider, who is considering developing such an inverter in the near future. 5 Conclusions A number of systems were installed in the French case study, including a 750 L DHW tank connected to the heat exchanger of the biomass urban heating network, dual-technology solar modules that provide both thermal and photovoltaic energy, and a modular all-in-one smart roof edge solar energy system. The choice of technologies resulted in the fulfilment of the project’s energy and cost-related performance goals: a low net-regulated energy consumption of only 16 kWh/m2/year and 55.8 kWh/m2/year of energy produced from local renewable energy sources, at a construction cost that was 18.4% lower than in an NZE reference building. However, a significant number of challenges were encountered during the project, as several planned technological solutions had to be abandoned or adjusted due to various difficulties encountered in their realization. This underlined the need for the inclusion of all relevant stakeholders throughout the project’s various phases. For example, an alignment between the local urban plan and the ZEROPLUS approach in the early stages of design would have prevented the design and then cancellation of a combined wind and solar energy generation system. Such challenges could be met through the full application of a comprehensive methodology to support integrated project management, which is described in the second part of this chapter.

7

Part 2: Project and design management – best practices and tools Shabtai Isaac

1 Introduction As the French case study and other case studies have shown, there are multiple benefits for NZE settlements and neighborhoods. Greater energy efficiency and economies of scale, resulting in lower costs, can be achieved through the transition from single NZE buildings to NZE communities. Yet as we learn from ZERO-PLUS, such a transition can also be challenging to realize. This raises the need for both effective project management practices and for tools and methods that can support the application of these practices. The following sections describe in detail the collaborative project management approach that facilitates the creation of NZE communities (Section 2), and the tools and methods that were developed in ZERO-PLUS to support it (Section 3). 2

Collaborative project management

In all the ZERO-PLUS case studies, numerous stakeholders were involved in all phases of each project, working together and continuously exchanging updated information. This experience underlines the need for collaborative project management practices, which enable the different stakeholders to simultaneously design the settlement and plan its construction. This, in turn, has resulted in both cost reductions and lower energy consumption of the completed buildings. It is important to note that the operational phase must be taken into account from the outset of the project as well, as it accounts for the largest share of energy demand. This will require the smart operation of the building by the building user – an aspect that can be challenging and requires preparation. Essentially, the implementation of NZE communities in ZERO-PLUS was found to face two main issues: 1. The need to align the projects with local planning policies and regulations. 2. The challenge of managing and integrating the numerous project stakeholders. 2.1   Aligning the design with policy and regulations

When making the transition from single NZE buildings to NZE settlements, the various components in the design (different innovative technologies, shared energy DOI: 10.1201/9781003267171-11

136  Shabtai Isaac resources, and communal energy management systems) need to be aligned with the relevant local policy and regulation frameworks. These frameworks may contain guidelines and by-laws that can either facilitate or prevent the implementation of the proposed design for the settlement. Local energy companies also play an important role in enabling renewable energy sharing programs, and thus motivating the project stakeholders to develop and implement them. As the French case study showed, it is, for example, important to align the project with existing long-term urban plans, which are usually initiated and prepared by local and/or national authorities. The project team should strive to familiarize the local planning authorities with the goals and approach of the NZE settlement and involve them in the project from the outset, to avoid the risk that they will be reluctant to approve its implementation. The full understanding of local planning authorities of the unique nature of the project, and ensuring that it is in accordance with the relevant national and local regulations, can streamline the process of obtaining building permits and prevent delays in their approval. It is also important for the project’s management to study the relevant regulations that may or may not allow energy sharing schemes within the settlement. For example, the Italian government approved relatively recently a new regulation that allows the sharing of renewable energy within settlements according to the European directive on the promotion of RES. This was a significant barrier in the Italian case study in ZERO-PLUS. In addition, it is important to involve utility companies at an early stage of the design, to ensure that these were willing to approve the planned communal energy generation and management systems and the installation and connection to the electrical grid of any innovative hybrid renewable energy systems that may be planned for community use, such as a combined wind–solar energy system. 2.2  Managing and integrating project stakeholders

In addition to the involvement of external stakeholders such as local planning authorities and utility companies, it is important to ensure the coordination and integration of the internal stakeholders in the project – the project owner, designers, technology providers, construction companies, occupants, and facility managers. The necessary interactions between these stakeholders need to be ensured and supported throughout the projects. This should preferably be handled by an experienced project manager who has a broad overview of the project. A close collaboration of all the project’s stakeholders is required throughout its various stages – from early planning to design and execution – to enable optimal energy performance, project duration, and cost. The owner in particular is a key member of the project team and should be committed to a high level of involvement and frequent communication with other project team members for it to succeed. Other important project stakeholders include the designers, technology providers, construction companies, and facility managers. The realization of the concept of NZE settlements requires access to participants with the relevant expertise, and this is an important factor that should be taken into consideration when

7.2: Project and design management 137 initiating the project. Project initiation should focus on assembling the experts into an aligned team with good internal communication so that they can tackle the various aspects of the project involving the design, construction, and monitoring of an NZE settlement. The integration of innovative technologies in the settlement’s systems requires timely information sharing between the construction company, technology providers, and suppliers. Technology providers in particular emerged in ZERO-PLUS as core members of the project team who need to be involved early on in the project to support the integration of the technologies in the design and the evaluation of their expected and actual performance. Continuous monitoring may be essential for performance evaluation and energy management of the settlement after it is occupied. Consequently, a monitoring coordinator and IT engineer should also be part of the project team. The monitoring coordinator leads the overall planning and implementation of the monitoring framework, which includes measurement and sensor specifications, design of the monitoring schema, monitoring equipment placement, and monitoring quality control procedures. The IT or data engineer is the developer of the platform through which the monitored data are being recorded and ensures the correct functioning of the monitoring schema and the data logging platform. Finally, non-experts, such as the buildings’ occupants, also need to be highly involved in the process. Since the project owner is not necessarily the final homeowner and/or occupant, their level and stage of involvement may differ from one project to another. It is essential to ensure a common understanding and agreement among the owners of different homes in the settlement. Such an agreement should cover the sharing of energy and the design, use, and maintenance of common technologies. The cooperation of occupants is also essential for the sustainable operation of the building’s systems and to obtain their approval for the installation of indoor monitoring systems and their participation in periodic surveys. 3 Integrated design and optimization The main aim of the work performed for the integrated design and optimization of the settlements is to help size and select the optimum configuration of innovative technologies and integrate them in the architectural and engineering design of the settlements. In the ZERO-PLUS approach, the design of settlements is the outcome of three strongly interrelated tasks (Figure 7.4): 1. Initial integrated design. A certain set of candidate technologies is evaluated to achieve the required energy performance and minimize construction costs, based on energy generation and consumption projections that are produced with the help of simulation tools, first at the building level, and then at the settlement level. 2. Technical and financial optimization. The initial integrated design is further improved to minimize life cycle costs while ensuring the settlement’s thermal energy environmental efficiency. An additional assessment is carried out using

138  Shabtai Isaac

Figure 7.4  Design process of the NZE settlements.

life cycle cost (LCC) analysis to determine the costs incurred by operating the energy and environmental systems chosen for the settlement. 3. Control and verification. Actual performance is ensured by developing and applying cost and change management processes, as well as commissioning and measurement and verification (M&V) plans. 3.1  Initial integrated design

The initial integrated design focuses on the selection of the types of innovative energy and environmental technologies to be implemented in the project. Through this process the systems and techniques can be selected at both building and settlement level and integrated in an overall combined design. This initial selection of technologies is an outcome of an iterative process, which is continued until the performance targets of the project are met. The assessments of the energy consumption of the buildings and of the production potential of renewable energy systems incorporated in the communities are based on energy modeling. Advanced simulation techniques, appropriate for the building and settlement levels, are thus used to calculate the energy and environmental performance of each proposed system and its components. The weather and climate uncertainties are considered in these simulations. In parallel, an initial cost analysis is performed. Based on the results of the energy and economic analysis, the energy conservation, energy management, and energy production technologies are selected. 3.2  Technical and financial optimization

The optimal sizing of each selected technology can then be defined to further improve the energy performance and reduce the overall cost of the settlements. This is done through the implementation of a life cycle cost (LCC) analysis and optimization process. The objective of this process is to identify the specific configuration of the selected technologies that will reduce the system’s LCC as much as possible (objective function) and yet fulfil the project’s performance targets (constraints). In ZERO-PLUS, an LCC analysis and optimization tool was developed to

7.2: Project and design management 139 automatically calculate and present such an analysis. The objective of the tool is to analyze the total LCC of the technologies in the initial design of a project and collect the required data for the LCC optimization. Initial, operational, maintenance, and end-of-life costs are taken into consideration for the LCC analysis. The total LCC of the technologies is calculated for the project as present value in €/m2. The results are considered as a reference point for performance measurement of the LCC optimization process. The output of the optimization is the economically optimum number of units of each selected technology. After the optimization process is completed, sensitivity analyses are carried out to examine the robustness of the achieved results. 3.3  Control and verification

At every step of the construction phase, collaborative and synchronized work between the project team members is ensured by following previously defined cost and change control processes and detailed commissioning and M&V plans. Cost and change control. A cost management program should be applied during the design and execution of the project to prevent cost overruns that would affect the project’s goals. A  change management process should also be implemented to identify for each change requested by a project stakeholder during the design and execution of the project, the expected implications of the requested change, and the consequent cost of the change. In ZERO-PLUS, the cost management program included the development and application of a dedicated cost control tool that was linked with the previously described LCC analysis tool. The cost control tool facilitated the preparation of preliminary cost assessments and the definition and monitoring of budget reserves. Some of the data in the tool was provided by the user, while other data could be automatically calculated. Using the tool, the costs of the project could be continuously monitored throughout the design and execution process to prevent unexpected cost overruns. Change management. The objectives of the change management process are to allow project partners to identify, examine, and discuss the implications of every proposed change before it is implemented, in order to prevent deviations from project goals. The implementation of changes can thus be monitored to ensure that their implications are correctly identified when the changes are requested. In ZERO-PLUS, a dedicated change management tool was developed that was linked to the previously described cost control and LCC analysis tools. The change management process implemented through the tool has four major components (Figure 7.5): 1. Definition of the proposed change 2. Identification of the expected impact of the proposed change on the project’s performance targets 3. Determination of the dependencies that connect the technologies in the system, in order to identify the implications of a change on other subsystems 4. Documentation of the data on each proposed change and its assessed implications

140  Shabtai Isaac

Figure 7.5  Change management process.

Commissioning. The main purpose of a commissioning plan is to provide key guidelines and support the owners of the project in order to ensure proper implementation of the selected technologies and help them navigate through this complex process. The plan provides detailed information on proposed actions that could be implemented by the project owners in the assembly, installation, and preoccupancy phases of the project. The general sequence in which these actions are carried out is: 1. Commissioning of each innovative technology 2. Building diagnostics 3. Monitoring of performance of the technologies during the pre-occupancy phase For the assembly and installation phases, basic checklists should be provided for the commissioning of each innovative technology. For the pre-occupancy phase

7.2: Project and design management 141 building diagnostics and systems, tests need to be defined for measuring and verifying the performance of the different technologies, as well as actions for testing the monitoring system, and for guiding the building users. The commissioning plan contains basic checklists for commissioning each innovative technology during its assembly and installation. These checklists describe the performance tests to be carried out and the parameters to be checked after completing the installation of each system separately and as a stand-alone scenario. The checklists are provided in a form that can be easily printed and used by the project owners (Figure 7.6). They allow the project owners to check the implementation of each technology and to detect, as far as possible, deficiencies while construction is taking place and before the pre-occupancy phase. The commissioning plan also specifies a number of different building diagnostics tests to be carried out after the completion of the construction, to evaluate the physical performance of the building envelope for heat loss, and to ensure that calibrated building energy simulations can be executed in the pre-occupancy phase. These include mandatory air permeability and U-value tests, as well as additional

Figure 7.6  Example of a checklist for the installation of a technology.

142  Shabtai Isaac optional tests, such as infrared thermography, co-heating, and U-value tests. The final selection of tests to be carried out should be done based on the consideration of constraints, such as the schedule, costs, and expert availability. The plan also specifies several building pre-occupancy tests that measure energy generation, energy end uses, and indoor and outdoor environmental conditions (temperature, humidity, CO2, etc.), namely: 1. Metering/sub-metering (and/or BMS data collection) (e.g., ventilation system, renewable technologies) 2. Walkthrough survey (photographic or video documentation) 3. Environmental spot measurements, ongoing on-site monitoring, and climatic data collection (weather station) In addition, a variety of tests are described in the plan that are to be executed to ensure that all the innovative technologies are performing (simultaneously and separately) according to the project’s goals, under full and partial load conditions. Monitoring protocols are prepared for measuring and verifying the energy savings and production provided by the different technologies and the parameters that need to be measured for each technology (Figure 7.7). Finally, instructions for the installation and testing of the monitoring system are provided in the plan as well.

Figure 7.7  Example of the specification of pre-occupancy tests.

7.2: Project and design management 143 Pre-occupancy monitoring and verification. The procedures provisioned for this stage are intended to monitor both the simultaneous and individual performance of the systems and to evaluate them against the project’s targets. Pre-occupancy monitoring data should be acquired for approximately one to two months so as to provide a baseline of performance that is needed for the calibration of the installed systems. Tests include building diagnostics tests for the evaluation of the physical performance of the building fabric, and system testing for the measurement of the performance of the technologies, the energy uses, and environmental parameters. The monitoring system should be tested as well according to a series of tests that are decided and implemented by the monitoring coordinator to collect data and cross-check them with the data provided by the internal data logging of each individual device in order to verify the performance and accuracy of the system. 4 Conclusion NZE settlements and neighborhoods have multiple benefits in terms of greater energy efficiency and lower costs yet can also be challenging to realize. This chapter described in detail the collaborative project management approach that facilitates the creation of NZE communities, and the tools and methods that were developed in ZERO-PLUS to support it. These tools and methods enable the integrated design, technical and financial optimization, cost and change control, commissioning and pre-occupancy monitoring, and verification of the projects.

8

Part 1: Concentrating solar energy – the FAE system Fabio Maria Montagnino

1 Introduction Concentration photovoltaic (CPV) systems have been specifically researched and developed in the last decades for application in regions of high DNI (Sharaf & Orhan, 2015a, 2015b). These devices include a solar concentrating system pointing into highly efficient photovoltaic cells. Multi-junction cells are usually employed, as these achieve higher efficiencies, delivering high voltage and currents despite their small size. Their further development should result in an increase in the conversion efficiency, boosting the power density of the CPV modules, that is, the amount of electric power that can be generated per unit of solar collecting surface, with a consequent reduction in the land footprint of solar systems. Figure 8.1 shows the realized and expected trajectories in the development of efficiency in multi-junction cells, CPV modules, and CPV systems. CPV systems are usually equipped with a primary concentrator (either reflector or refractor), a photovoltaic receiver that is located at the focal point of the primary optics and, eventually, a secondary optic stage to improve the concentration. The CPV module is mounted on a two-axis very accurate sun-tracking system which assures the continuous and accurate alignment of the optics with the direct solar radiation. As multi-junction cells can operate at relatively high temperatures that are compatible with the combined generation of heat for domestic applications or industrial processes working at mild temperature ranges, concentration photovoltaic and thermal (CPV/T) modules have been developed to integrate the CPV with an active thermal energy recovery circuit which delivers both electric and thermal energy (Renno & Petito, 2013, 2016; Settino et al., 2018; Mittelman et. al, 2007). High-concentration photovoltaic and thermal systems (HCPV/T) represent an evolution of CPV/T ones, designed to achieve very high levels of concentration (>500). As a matter of fact, the advantages of CPV and CPV/T systems are enhanced at high concentrations due to the further improvement of the ratio between the surface of the collector and the receiving cell. The trade-off is represented by the need for tougher tolerances in the opto-mechanic mounting and even higher accuracy in the tracking system.

DOI: 10.1201/9781003267171-12

8.1: Concentrating solar energy – the FAE system 145

Figure 8.1 Development of record efficiencies of III–V multi-junction solar cells, CPV modules, and top-of-the-line CPV system efficiencies. Trend lines show expected efficiencies from the Strategic Research Agenda (SRA) developed by the European Photovoltaics Technology Platform in 2011. Source: Wiesenfarth et al. (2017).

2 The HCPV FAE system The FAE system has been developed by IDEA Srl, an Italian company specialized in the design and fabrication of solar systems (Paredes et al., 2015). It is composed of two semi-trackers, each consisting of ten coupled mirrors and receivers, mounted on a superalloy A-286 stainless-steel frame support. An Alt-Azimuth tracking system keeps the mirrors aligned with the sun by the continuous rotation along the N–S horizontal axis for altitude tracking and the tilt of the E–W transverse axis for azimuth alignment. The two movements are regulated by an AN8 magnetic encoder position sensor and are provided, respectively, by a Bernio MR 615 30Q 1/1024 coaxial gear rotational motor and a Linak LA25 linear actuator. Figure 8.2 shows a 3D representation of the module, where the 20 primary mirrors are clearly visible. The geometry of the primary mirrors is generated from a rotationally symmetrical paraboloid of a focal length of 350 mm. The mirror mechanical center is 245 mm apart from the paraboloid optical axis, and its effective focal length is 363 mm. The plane projection of the mirror is a square of side 450 mm; its curved surface area is approximately equal to 2,025 cm2. The mirrors are manufactured in silver-coated ultraclean solar glass, with a reflectance of 95%, as specified by the manufacturer. The receiver includes a TaiCrystal InGaP/InGaAs/Ge triple-junction (TJ) solar cell, which is incorporated into an active heat sink. An inverted truncated pyramid (ITP) is placed with the larger face at the mirror focal point, and the smaller one glued upon the TJ cell. It performs as a light pipe secondary optics,

146  Fabio Maria Montagnino

Figure 8.2  Three-dimensional representation of an FAE module.

Figure 8.3 Detailed view of the HCPV FAE receiving module (left). The ITP light pipe is represented in blue (right).

with an entry surface area of 16 mm × 16 mm = 256 mm2 and an exit surface area (corresponding to the TJ cell) of 10.3875 mm × 10.3875 mm = 107.90 mm2. This results in a geometric concentration factor of Cg = 1,875×. Figure 8.3 illustrates the coupled mounting of the primary reflector and the receiver. The right side of the figure shows the detail of the ITP light pipe coupling the primary optics with the cell, which is glued on its exit surface. The cell achieves high efficiency in the conversion of the sunlight into electricity due to the different bandgaps characterizing each of the three sub-cells, as shown in Figure 8.4. The superficial InGaP junction has a bandgap of approximately 1.88 eV, which is designed to absorb in the UV–Vis spectrum. The underlying InGaAs subcell captures the non-absorbed IR photons up to approximately 885 nm, which corresponds to the bandgap of 1.39 eV. The remaining photons finally reach the Ge layer that absorbs in the 885–1,900 nm range (0.67 eV bandgap).

8.1: Concentrating solar energy – the FAE system 147

Figure 8.4 Structure of an InGaP/InGaAs/Ge triple-junction (TJ) solar cell with the three absorption bandgaps reported on the sunlight spectrum. Source: Anaty et al. (2016).

Each cell is embedded into an active 100 mm2 aluminum (Al) heat sink to extract its thermal energy. The active cooling system keeps the InGaP/InGaAs/Ge TJ solar cell at an operating temperature in the range of 20°C to 90°C through the continuous circulation of demineralized water with added glycol. A maximum temperature of 110°C can be reached without damaging the cell, even if a significant reduction in its efficiency will be observed. The active heat sink has a single inlet and a single outlet point; in between the fluid flows in a thin gap beyond the TJ solar cell, which is directly exposed to the flow. A Priux Master 25–90 circulating pump and a 0.2 m3 demineralized water storage tank are integrated into the reverse return closed-loop hydraulic system. In order to achieve the required accuracy, the control system is combining an open-loop and a closed-loop logic. The open-loop makes use of the solar position algorithm (SPA) of the National Renewable Energy Laboratory (NREL), which is a reliable astronomical tracking algorithm widely used to point the sun. The tracking accuracy that can be achieved by the open-loop logic is increased on clear-sky sunny days by the intervention of the closed-loop control logic, which moves the actuators in order to keep the image of the sun in the center of a complementary metal oxide semiconductor (CMOS) installed in the N-side of the module configuration. A control panel manages the two-axis tracking system and acquires operative parameters (such as current, voltage, flow rates, demineralized water temperature, solar position angles, etc.). The electric layout of one module consists of a parallel circuit arrangement of the two semi-modules (N-side and S-side), each consisting of ten TJ solar cells placed in series. The hydraulic/thermal system is integrated into the control panel too: two YF-S401 volumetric flowmeters that can measure the flow rate between 0.3 l/min (5 × 10–6 kg/s) and 6 l/min (1 × 10–4 kg/s) at water

148  Fabio Maria Montagnino Table 8.1  Characteristic features of FAE HCPV/T Feature

Value

Thermal peak power Electric peak power Width Length Height (at the rotating axis) Weight Number of receivers Size of reflecting mirrors Concentration factor Maximum operational wind speed Maximum wind speed stowed

1kW 2kW 1.2 m 7.3 m 1.5 m 450 kg 20 45x45 cm ≅ 2.000 54 km/h 100 km/h

pressure 0.8 MPa gauge with an accuracy of ±5 % are installed in the east side (E-side) and west side (W-side) of each semi-module. The temperature of the heat transfer fluid is measured at each semi-module inlet outlet by PT100 platinum thermometer sensors with an accuracy of ±0.05%. All data are collected and recorded by a supervising microcomputer in a MySQL database. The HCPV/T module is finally equipped with a 1,000 W smart grid tie variable load micro-inverter. The characteristics of the module are summarized in Table 8.1. 3 Results The monthly and annual production of FAE has been evaluated from measurement campaigns, and it is in substantial agreement with the finding of calculations applying consolidated CPV/T analytical models. The calculated average daily electric efficiency of the system reaches 33%, while the recorded experimental peak efficiency is 30%, and the thermal efficiency reaches 50%, in line with the analytical model. The HCPV/T system is, therefore, able to produce up to 1 kW of electric power and 2 kW of thermal power, offering a hybrid source of energy that is suitable for apartments, commercial buildings, and small industrial applications that require on-site combined heat and power. The system has been integrated into the ZERO-PLUS demo site in Cyprus, supplying electricity and heat in a polygenerative configuration, including the solar cooling module Freescoo. 4 Limitations and future developments: toward a DL/HCPV/T system The pilot installations in Italy and Cyprus have shown the critical role of the tracking system, which should maintain a very high accuracy to assure the nominal performance. Also, the heat recovery circuit presents critical aspects toward industrialization, as its topology is complex, the components are still expensive, and

8.1: Concentrating solar energy – the FAE system 149 some risks of failure are determined by the possibility of obstructions in the pipe network, with consequent overheating of the cells, which may result in serious damage. A possible solution would be the removal of the cells from the collector and their installation in an integrated and sheltered receiver, where the cooling circuit would be more compact and simplified. The level of concentration could be relaxed in order to increase tolerances and therefore reduce costs of both mechanical and optical components, as well as of the tracking system. Transport of light from the concentrator to the cells could be achieved by waveguides, having both high transparency in the solar spectral range and high resistance to concentrated light. In this scenario, an additional function of FAE could be envisaged, as the transmitted light may also be used to directly illuminate interior spaces. A preliminary work to transform FAE into a multi-functional daylighting/highconcentration photovoltaic thermal device (DL/HCPV/T) system has been initiated. Using Zemax OpticStudio18, an upgraded module has been simulated, in which the receiver was replaced with either three bare fibers of different size, a fiber bundle, an end-capped fiber, an aspheric lens, or an aspheric telephoto lens. The aspheric telephoto lens and the fiber bundle resulted in the two bestperforming optics. The former reduces the image size and angular aperture with virtually no power loss, although its design is more complex and expensive. The latter concentrates the sunlight without significant loss, and it is cost-effective and easy-to-handle. Large-diameter optical fiber made of high-purity, low-hydroxyl silica, although still far from commercially viable efficiencies, represents a quite promising material for the development of prototypes of single multi-functional systems to provide effective lighting and energy supply for domestic and commercial buildings. 5 Conclusion The development of the FAE HCPV/T system represents a step forward in the achievement of high conversion rates of solar energy into electricity and thermal energy. The experimental module achieves a total efficiency of about 80% in converting the DNI radiation to provide electric power and domestic water heating. Nevertheless, some further improvements are required before the industrialization of FAE in order to simplify the design, reduce the cost, and minimize the risk of faults. Hereby, has been presented a strategy that takes into account the introduction of optical fibers to reposition the receivers and review the overall design of the mechatronic and hydraulic system. References Anaty, M., Merouan, B., Bouziane, K., Aggour, M., & Mohamed, E. (2016). Modeling and simulation of a C3MJ+ triple junction solar cell using Matlab/Simulink, 752–757. https:// doi.org/10.1109/IRSEC.2016.7984015 Mittelman, G., Kribus, A., & Dayan, A. (2007). Solar cooling with concentrating photovoltaic/thermal (CPVT) systems. Energy Conversion and Management, 48, 2481–2490.

150  Fabio Maria Montagnino Paredes, F., Montagnino, F. M., Salinari, P., Bonsignore, G., Milone, S., Agnello, S., Barbera, M., Gelardi, F. M., Sciortino, L., Collura, A., & Lo Cicero, U. (2015). Combined Heat and Power Generation with a HCPV System at 2000 Suns (pp. 2–7). Melville, NY: American Institute of Physics. https://doi.org/10.1063/1.4931550 Renno, C., & Petito, F. (2013). Design and modeling of a concentrating photovoltaic thermal (CPV/T) system for a domestic application. Energy and Buildings, 62, 392–402. Renno, C., & Petito, F. (2016). Experimental and theoretical model of a concentrating photovoltaic and thermal system. Energy Conversion and Management, 126, 516–525. Settino, J., Sant, T., Micallef, C., Farrugia, M., Staines, C. S., Licari, J., & Micallef, A. (2018). Overview of solar technologies for electricity, heating and cooling production. Renewable and Sustainable Energy Reviews, 90, 892–909. Sharaf, O. Z., & Orhan, M. F. (2015a). Concentrated photovoltaic thermal (CPVT) solar collector systems: Part I – Fundamentals, design considerations and current technologies. Renewable and Sustainable Energy Reviews, 50, 1500–1565. Sharaf, O. Z., & Orhan, M. F. (2015b). Concentrated photovoltaic thermal (CPVT) solar collector systems: Part II – Implemented systems, performance assessment, and future directions. Renewable and Sustainable Energy Reviews, 50, 1566–1633. Wiesenfarth, M., Philipps, S. P., Bett, A. W., Horowitz, K., & Kurtz, S. (2017). Current status of concentrator photovoltaic (CPV) technology. Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany National Renewable Energy Laboratory NREL in Golden, Colorado, USA.

8

Part 2: Bot-based building design Brooke Spreen and Sven Koehler

1 Introduction Despite the ongoing digital revolution, technologies such as cloud collaboration and automation are still largely foreign to the building design industry. Architects and designers juggle creative problem-solving with manual, repetitive tasks. Threedimensional models, where used, are usually locked in desktop software and can be accessed by only one user at a time. Industry-standard software utilizes direct modeling workflows, where small mistakes or design changes can lead to costly rebuilds. The scope of input data, including various norms, regulations, climate metrics, usage forecasts, and customer targets, can be staggering. Complicating the issue, the definition and detailed specification of nZEB, ZEB, ZERO-PLUS, and other sustainable building standards are often highly complex, further increasing the burden and cost of technical design. In an effort to combat these increased costs, the efficiency of the design process can be improved. This is especially important to avoid counterincentives to the adoption of sustainable building standards. The authors see an opportunity to apply technologies which have been proven successful in other industries – mechanical and software engineering – to the building design process. As a first step, they have proposed and prototyped a cloudbased software solution which designers can use to model rooftops. Though the software started as a tool for planning the ZERO-PLUS solar installations in Voreppe (see Chapter 7–1), it has since been expanded to address all major roof technologies, thus making it appropriate for the design of “multifunctional roofs” – those which combine multiple design criteria (insulation, drainage, energy production, green roofing, etc.). After a year of real-world testing, the software demonstrates both clear benefits and potential for further improvements. This chapter begins with an outline of the current shortcomings and accompanying potential improvements of the roof planning process (Section 2). A design specification for a new planning software follows in Section 3, and the resulting implementation of this specification (Anerdgy’s “Roofbot” software) is discussed in Section 4. Section 5 reflects upon the challenges and potentials observed during the last year of Roofbot testing.

DOI: 10.1201/9781003267171-13

152  Brooke Spreen and Sven Koehler 2 Roof design – current difficulties The roof design process of sustainable buildings presents several opportunities for optimization. Tasks driven by linear logic, often dictated by norms and building codes, can be automated, as can significant parts of the reporting process. A procedural modeling workflow, where models are built by an adjustable algorithm, allows for clear communication of design intent and facilitates subsequent updates. The library of norms required by a multi-functional roof can be largely implemented in code, decreasing overhead and minimizing calculation errors. Finally, the selection of an optimized roof design requires the analysis and comparison of multiple options, which in turn necessitates the efficient generation of multiple designs in parallel. 2.1  Automation

The increasing demand for low-footprint and sustainable building stock significantly increases the workload required of building designers. The roof, for example, has evolved from a relatively inconspicuous area whose primary technical requirement was to provide robust weatherproofing to a multi-functional area which must integrate the design requirements of energy production, rainwater management, biodiversity, and public-use spaces. Designing such interdisciplinary systems, with their inherent overlaps and trade-offs, represents a significant increase in the time and cost investment required of a building designer. Any tool to decrease design workload translates to reduced costs, which, by extension, reduces one of the barriers to ZEB adoption. Though roof design is too complex to fully automate, careful selection of clear, logical, and linear subtasks can significantly reduce the designer’s workload. 2.2  Procedural model generation

Procedural model generation refers to the process of creating a model via a linear series of programmable steps, as opposed to direct modeling, where no record is preserved of the steps taken to reach the end model state. Though procedural modeling has been widely adopted in mechanical engineering CAD systems and is used in some cases for bulk generation of buildings (Müller et al., 2006; Esri), the most common architectural modeling programs still rely on direct modeling. This makes the communication of design intention, design accountability, and the implementation of any subsequent updates very difficult. 2.3  Encoded norms and building codes

Several codes and building norms prescribe constant values or required calculations as part of the design process. Keeping track of these norms, especially if the design office has projects in multiple countries, can be a challenge, as can the manual checks to ensure that the project is fully in compliance.

8.2: Bot-based building design 153 As they usually rely on clear, linear logic, these values could easily be coded into software. The software could also check for compliance with the building codes by reporting errors if required values are not met. 2.4  Configurable modeling and generation of options

The multi-dimensional nature of roofs means the large range of options can be difficult to grasp – meaning, it can be relatively easy to settle on a less-than-optimal design. In most cases, it would be ideal to conduct a preliminary analysis of multiple roof configurations to allow for informed comparisons regarding price, energy production, weight, etc. With conventional building design, however, total design cost increases roughly linearly with the number of options under consideration. Economies of scale fall apart when most of the work executed for an initial option must be replicated for every additional option. This means project managers are forced to prematurely narrow their design focus. As a result, decision-makers lack key information when the time comes to settle on a final design. A configurable model which can automatically regenerate to reflect changes in its input values, however, would allow additional options to be produced at a fraction of the cost. 3 Bot potential – design requirements Leveraging the opportunities for improvement discussed earlier, Anerdgy has prototyped a new roof design software. This section summarizes the primary design specification of that software. An overview is shown in Figure 8.5. 3.1  Primary design requirements

In order to semi-automate the roof design process, it was envisioned that a program (“bot”) takes over straightforward tasks (e.g., rainwater calculations, placement of solar modules), allowing the designer to focus on decisions that require more critical thinking. In determining the extent of automation, tasks should be prioritized that fall in the intersection of low complexity and high work effort (see Figure 8.6). In this way, the bot is a tool to supplement, but not replace, the designer’s workflow. If the bot facilitates the creation of a configurable, procedurally generated model of the roof, multiple options can be efficiently created and compared. The bot should handle all required calculations and include built-in error checking. Data export must be facilitated for the 3D model, generated 2D images, and calculation results. For accountability, an output log of all implemented norms and a record of all significant calculations should be generated. Reporting should be automated as much as possible. 3.2  Secondary design requirements – “nice-to-haves”

Ideally, the bot would leverage modern, cloud-based computing platforms to ensure computer-agnostic access, robust software updates, and easy collaboration

154  Brooke Spreen and Sven Koehler

Figure 8.5  Mind map of the requirements of a bot-based design software.

(Figure 8.5). This also opens the possibility for a new method of client communication – where links can allow direct viewing of the model and final report from any browser. Integrated version control (similar to GIT, which is used for software development) would enable robust tracking of updates and iteration. BIM integration would fully modernize the system. 4 Anerdgy Roofbot implementation Anerdgy’s Roofbot software is one potential implementation of the requirements listed in Section 3. It is a collection of codes that assists the designer in modeling, calculating, and reporting and which operates on top of existing commercial cloud platforms. Model generation and design calculations are executed in Onshape, a browser-based 3D CAD system that supports procedural modeling, configurations, and custom scripting (Onshape, 2022a). Report generation and client communication are implemented in Google Drive. In Onshape, Roofbot code is written in the built-in Featurescript language, which allows users to develop custom CAD functionalities. By storing attributes directly on modeled parts, the Roofbot scripts communicate with each other to semi-autonomously design and model multiple interlocking rooftop systems. The scripts execute procedurally (linearly) and allow for varying degrees of user input. When starting a project, the user imports or directly models the required building, which may have one or multiple roofs. Custom scripts are used to define all relevant project data (Figure 8.6) and to identify the surfaces where a roof is to be built. The Roofbot scripts then generate a default design, which the user can manually adjust or override as required. Final options are chosen and generated. A local app exports the resulting data and figures to Google Drive for reporting. These steps are explained in more detail in the following sections.

8.2: Bot-based building design 155

Figure 8.6 Screen capture of the Onshape interface showing their configurations and feature list (procedural modeling). Updating any of the configuration values or any feature in the feature list will trigger a rebuild of the entire model. On the right is the interface of Anerdgy’s custom “Project data” feature.

4.1  Defining constant roof geometry

After the import or creation of a building, roof modeling starts with the option to add additional fixed roof geometry, for example, access elements (doors, skylights, ladders) or obstacles (HVAC, vents, elevator machine rooms). If desired, elements can be marked such that subsequent scripts will automatically “float” the elements to the top of any generated roof layers. 4.2  Drainage

For each desired surface covering (i.e., gravel, vegetation, concrete tiles), the number and placement of drainage fields (roof areas with a single drainage outlet) are defined. The code calculates the required number and approximate size of the fields based on project location, then lays a default field raster over each roof. The user then adjusts the size and placement of the raster as needed. Real-time drainage calculations aid this process. Field surface color continuously updates to reflect the relation between calculated runoff and maximum permissible drain flow (Figure 8.7). Continuity of the drainage surface (i.e., no abrupt height changes) is ensured. Besides surface type, other configurable options include drainage system type (conventional vs. siphonic), gutters, and retention systems. 4.3  Technology families

The next step bundles together several rooftop technologies, including solar fields and roof layers (membranes, insulation, tiles, etc.). The user can then apply the default roof algorithm, which generates all selected items, or choose to configure

156  Brooke Spreen and Sven Koehler

Figure 8.7 Drainage field modeling. Colors indicate the relation between the calculated runoff from each surface and the maximum allowable flow rate. Red fields (not shown) are unacceptable, yellow is allowable, and green is comfortably below the limit. Light gray boxes around each drain indicate the forecasted water surface during the 5-year and 100-year 5 min storms (German standard DIN 1986–100).

the algorithm for specific technologies on specific roofs. An example generated roof is shown in Figure 8.8. 4.3.1 Solar fields

The solar field family covers multiple solar installation systems. Some are optimized toward low profile and low weight, others toward integration with green roofs or as in-roof installations. Installations can be configured regarding orientation (east–west, south, building-aligned), spacing, offsets, panel size and type, etc. Peak power and panel orientation are auto-calculated, allowing total annual energy production to be estimated during report generation. 4.3.2 Roof layers

The roof layers family builds all necessary roof layers (membranes, insulation, etc.), taking into account any sloped insulation calculated from the “Drainage” step and the location of any installed roof technologies. Users can select from preconfigured roof types (i.e., extensive green roof, gravel) or build their own layer configuration. Layer weights and volumes are calculated and stored for export. Depending on which other technologies are installed, extrastrong insulation may be installed in some areas, or vegetation may be selectively replaced by gravel (i.e., under low solar fields). Total layer heights are calculated, and all relevant items are automatically lifted to the new rooftop surface.

8.2: Bot-based building design 157

Figure 8.8 Example model generated using the Roofbot. Raised butterfly solar panels permit the installation of a green roof across the entire building (based on a system by Zinco GmbH (2022)). An interactive model can be accessed via https:// tinyurl.com/roofbot-demo. For viewing on a mobile device, the Onshape app is recommended. 4.3.3 Other families

The Roofbot also generates other rooftop technologies, including fall protection and lightning protection. Besides the auto-generation of safety rails, fences, lightning rods, etc., post-processing modules facilitate the visualization of fall danger zones as well as lightning cones and the rolling ball method. 4.4  Report generation

A central app leverages the Onshape API to transfer all relevant figures and data to the Roofbot reporting module, which is based in Google Drive. The app also pulls data from the PVGIS database (EU JRC, 2019) and calculates an estimated annual power output for the installed solar capacity. Software written in Google Apps Script assists with processing the data (Google, 2022), a cost matrix is applied in Google Sheets, and the final report comes together in Google Docs. The report and supporting material can be shared in read-only form with clients, enabling transparency and streamlining the communication of any necessary updates. 4.5  Iterations

One of the greatest strengths of a procedural system comes into play during the inevitable update process. When the project demands adjustments to initial assumptions, these can be integrated, and the system will automatically regenerate to take them into account. Though some manual adjustments may be needed depending on the nature of the update, hours of rework can generally be avoided.

158  Brooke Spreen and Sven Koehler 5 Challenges and potential impacts To date, the Anerdgy Roofbot has been used in the initial design of approximately 20 buildings. It is continuously evolving, and although most of the desired features have been implemented, some (including BIM export and logging of all calculations) are still under construction. It has nonetheless proved to be a valuable tool for the design of technical roofs. 5.1  Challenges

From a broader viewpoint, there are a few challenges to the widespread use of a bot-based design process to consider. For bot systems built on third-party cloud platforms, their biggest asset is also a liability. For all the benefits of cloud-based software, the bot will always be limited by the capabilities of the underlying platform. This can manifest as limited computational power or a lack of needed features and can be compounded if the bot users represent a relatively small percentage of the platform’s total user base. For example, despite its impressive modeling and scripting capabilities, Onshape was primarily developed as a CAD system for mechanical engineering and currently has little incentive to prioritize native support for IFC file export (Onshape, 2022b). Computational power can also be an important topic. Building models, by necessity, require a monumental amount of data. As with existing programs, careful application of graded level of detail (LOD) models goes a long way to maximizing model efficiency, and cloud-based computing opens up access to a much wider range of user-side computers (laptops, non-Windows operating systems), but users are still at the mercy of how the cloud provider allocates resource use. This has not yet been a blocking point for the cases tested with the Anerdgy Roofbot but may cause issues for solutions working with a higher LOD. Interoperability with existing programs is also a theme. Although SAT, STEP, and OBJ files are currently workable, the development of an IFC interface is a must. Ideally, the system would also be fully compatible with BIM workflows, including import, addition, and export of all BIM attributes, though the BIM standards will need to further solidify before this is seriously pursued. 5.2  Potential impacts

Despite these current challenges, the Roofbot has demonstrated the potential benefits of cloud-based procedural roof design. Wider adoption of similar technologies could significantly reduce the overhead associated with designing ZERO-PLUS buildings, accelerating their adoption and stimulating the market for the next generation of rooftop technologies. On a broader scale, similar benefits could be realized across the building design industry. 6 Conclusion Based on Anerdgy’s experience in the development and use of their Roofbot design software, the building industry can benefit from a semi-automation of the design

8.2: Bot-based building design 159 process. This is particularly true regarding sustainable buildings, where more complex building specifications must be considered. Cloud-based software ensures maximal flexibility, and the scripting capabilities of Onshape enable the generation of a procedurally created, configurable roof model. There is a significant potential for widespread adoption of this or similar technologies across the building industry. References Esri. (n.d.). Advanced 3D City Design Software | ArcGIS CityEngine. Retrieved February 8, 2022, from www.esri.com/en-us/arcgis/products/arcgis-cityengine/overview EU JRC. (2019). JRC Photovoltaic Geographical Information System (PVGIS) – European Commission: EU Science Hub. Retrieved February 7, 2022, from https://re.jrc.ec.europa. eu/pvg_tools/en/#PVP Google. (2022). Apps Script: Google Apps Script. Retrieved February 7, 2022, from www. google.com/script/start/ Müller, P., Wonka, P., Haegler, S., Ulmer, A., & van Gool, L. (2006). Procedural modeling of buildings. ACM Transactions on Graphics, 25(3), 614–623. https://doi.org/10.1145/ 1141911.1141931 Onshape. (2022a). FeatureScript introduction. Retrieved February 7, 2022, from https://cad. onshape.com/FsDoc/ Onshape. (2022b). Onshape | Product Development Platform. Retrieved February 7, 2022, from www.onshape.com/en/ ZinCo GmbH. (2022). Gründach und Solar | ZinCo. ZinCo. Retrieved February 8, 2022, from www.zinco.de/solar

8

Part 3: Solar air-conditioning – the Freescoo system Pietro Finocchiaro

1

Introduction

Building air-conditioning represents a large contribution on the overall building sector energy consumption, whereas the air-conditioning demand is growing fast in several areas of the world. The massive use of traditional air-conditioning systems based on vapor compression cycle causes problems during summer seasons in terms of energetic consumptions, environmental impacts, and network overhead. In the air handling systems, the latent load linked to the air dehumidification process is of considerable importance. In conventional systems, the dehumidification of the air takes place through the passage in a cooling coil where a coolant circulates at low temperature (6–7°C), causing condensation of the moisture on the surfaces of the heat exchanger. The condensate is then collected in a basin and evacuated. In this way, the air dehumidification process is inevitably associated with the cooling process. More in general, despite the seeming contradiction, it’s possible to use the heat to power a cooling cycle instead of electricity. This is the case of so-called thermally driven air-conditioning technologies which comprise absorption adsorption chillers and desiccant evaporative cooling (DEC) systems. In DEC systems, a different approach is used to dehumidify the air, in comparison to the mentioned condensation process which occurs in standard cooling coils fed by chilled water. Air dehumidification by adsorption uses the physical process by which water vapor molecules contained in the air are captured on the internal surface of a highly porous material (desiccant or sorbent) without the need to reach the dew point temperature. The water vapor migrates to the surface of the adsorbent due to the partial pressure difference. After a certain time of operation, the desiccant becomes saturated due to adsorption, and the pressure gradient decreases until it reaches the equilibrium. For the subsequent elimination of water vapor from the saturated desiccant material, it is necessary to bring the sorbent in contact with a stream of hot air, whose temperature depends on the type of material used (regeneration phase). The temperature of the regeneration heat used to release the trapped water vapor from the sorbent changes wildly depending on the specific desiccant material chosen. The most used sorbent materials in dehumidification systems are silica gel, DOI: 10.1201/9781003267171-14

8.3: Solar air-conditioning – the Freescoo system 161 lithium chloride, and zeolites. In the case of DEC systems powered by solar thermal collectors, one of the most used sorption materials is silica-gel, which can be regenerated even with relatively low-grade heat (60°C). Common DEC air handling systems using solid-state sorbent materials are based on dehumidifying rotors. The use of adsorbent rotors implies that the adsorption heat is first rejected on the process air and then removed by the evaporative cooling process. While the humidity rate is lowered during the dehumidification process, the air temperature increases, thus obtaining a quasi-isenthalpic transformation and, consequently, no production of cooling power. Furthermore, an increase in the temperature of the desiccant during the adsorption phase implies a higher regeneration temperature. Finally, in the adsorbent rotors, there is a relatively low quantity of desiccant material so that energy storing can be based on the quantity of fluid used for the regeneration (normally water in storage tanks). The second type of process used in DEC systems is the direct and/or indirect evaporative cooling, also called adiabatic cooling, which allows to cool down the air using the cooling effect of water evaporation. In direct systems, since water evaporates directly into the airstream, the temperature of the air is decreased, whereas humidity is increased. In indirect systems, cool air is produced without moist change. For a typical indirect evaporative heat exchanger, the primary air (or product air) and the secondary air (or working air) flow in separate passages. The secondary air in wet channel acts as a heat sink by absorbing heat due to water evaporation. In DEC systems, indirect and/or direct evaporative cooling solutions can be combined with the dehumidification process to achieve the desired air handling process. Globally, DEC cooling systems require water for the evaporative cooling, electricity to run the air fans, and thermal energy for the sorption material regeneration, but no electricity is used to drive a compressor. Therefore, DEC systems can achieve electrical efficiency four or five times higher than for vapor compressor cycles. 2 Concept Freescoo is an innovative air handling technology that uses low-grade heat (solar thermal, recovery heat by a heat pump, waste heat, district heating, and cogeneration) with functions of cooling, dehumidification, heating, heat recovery, and ventilation in buildings where air change is necessary. The Freescoo system uses a new DEC technology based on fixed and cooled sorption beds. Thanks to the use of this technology, the heat released during the air dehumidification phase can be removed in the sorption bed through a cooling medium. In the Freescoo system, the dehumidification and cooling process takes place inside a heat exchanger containing the desiccant material which captures the moisture within its porous structure. The heat generated by the adsorption phenomenon is then rejected on the other side of the heat exchanger. To increase the heat exchange, evaporative cooling is used.

162  Pietro Finocchiaro

Figure 8.9 Comparison among different dehumidification processes on the psychrometric chart.

The cooling cycle is described here on the psychrometric chart shown in Figure 8.9. A flow rate of ambient air which is warm and humid is drawn through one of the adsorption beds, where it is simultaneously dehumidified and cooled down (product air). The dehumidification process can be carried out with a slight temperature decrease with respect to the inlet conditions. Thanks to the heat exchange inside the heat exchanger, the adsorption heat can be rejected on the secondary side of the heat exchanger to another airstream, where water evaporation occurs. After a certain time of operation, the desiccant material tends to become saturated by the moisture, so its regeneration becomes necessary. In this phase, the exchanger is hit by a hot airstream, which dries the adsorbent material, restoring its initial ability to attract moisture from the air. For continuity of service in the system, there are two exchangers operating alternately in adsorption and desorption (regeneration). This has several advantages from an energetic point of view compared to the solution based on desiccant rotors, and in particular: • Greater adsorption capacity of the material, thanks to the low temperature that characterizes the dehumidification process • Greater energy efficiency of the whole air handling process • Possibility to store latent heat in form of adsorption capacity of the desiccant The main energy and environmental benefits of the Freescoo technology can be summarized as following: • High rated energy efficiency ratio (EER >10 and >20 at partial load). EER is the ratio between the cooling energy supplied by the system and the electricity used for its operation (electricity is used only to operate the fans, circulation pumps, and some auxiliaries).

8.3: Solar air-conditioning – the Freescoo system 163 • Installed electrical power commitment equal to 6–8 times lower than other conventional solutions for air-conditioning. • Use of low-enthalpy heat: the minimum temperature required for the operation of the system is 55°C. • High thermal efficiency. Thermal efficiency is the ratio of the cooling capacity to the heat source supplied. The thermal efficiency for DEC solutions based on adsorbent rotors is 50 kWh/m2 per year) are done by comparing the actual consumption/ production with the output of the calibrated thermal and energy models of the communities. If a significant difference is found, the problem identification procedure is initiated. The following values are tabulated in the report: • • • •

Total energy Average energy workday Average energy weekend Lost measurements For the aforementioned, indicators are calculated for the following: • • • • •

Past month Past month of the previous year Two months ago Expected from simulation Difference between actual and simulated value

The tabulated values include the average, maximum, minimum, and percentage of lost measurements for indoor temperature, relative humidity, and CO2 of the apartment. Also, the net-regulated energy consumption (heating, cooling, domestic hot water, fans, pumps, ventilation) and production of the individual sources are presented. All the calculated differences (between actual and simulated value) are colorcoded. If the difference is negative for achieving the KPI of the project, the value

180  Dionysia Kolokotsa et al. is color-coded as red, and if is positive, the color is green. Finally, the graphs of the following measurements of the past month are presented: • Indoor temperature (°C) • Relative humidity (%) • CO2 level (ppm) • Outdoor air temperature (°C) • Outdoor relative humidity (%) • Wind speed (m/s) • Solar radiation (W/m2) 5 Lessons learned and best practices 5.1 M&V planning and implementation

Experience from the implementation of the M&V framework on four pilot communities revealed that the design of the M&V is closely related to a project’s design development and optimization. It was identified that critical decisions for the M&V are made during the early design stages. During these stages, a clear vision of the M&V targets and expectations assists in identifying the measuring approach to be followed and, as a result, obtain a view of the expected effort in human resources and costs. During the design development phase, the building sensors’ placement needs to be considered along with interior and electrical design. Besides, the location of a weather station in the community needs to be decided at this stage. Therefore, at the end of this phase, a set of plans indicating the equipment’s location should be prepared. Furthermore, the electrical drawings need to include the monitoring installation. This design-phase planning assists the construction and installation phases, and it is highlighted through the lessons learned as a practice to be adopted in future projects. Planning of the M&V activities for construction and post-construction phase demonstrates that commissioning and the M&V are linked. Commissioning is closely related to measurement and verification because it ensures that the technologies and the monitoring schema are functional. Hence, it provides a trusted basis for assessing initial performance after installation that allows the elimination of “procurement” as a possible reason for poor performance when investigating a possible performance gap. 5.2  Quality control

Quality control is a significant task within the M&V planning and implementation, and an important subject of quality control has been the development and operation of the monitoring schema with a WebGIS platform in its core. The monitoring schema measures and collects parameters related to IEQ, building and community

Monitoring and evaluation of positive-energy communities 181 Table 9.5  Quality assessment of the collected data, quality indicator: completeness

Reasons for missing data % of missing data

Italy

UK

France

Cyprus

Equipment updates Electric power disruption COVID-19 20%

Equipment updates Electric power disruption 3%

Equipment malfunction

Internet connection issues

15%

1%

energy consumption, building and community energy production, energy storage (if implemented), and weather data. On the platform, the data are collected, analyzed, and visualized for immediate performance feedback. Implementation of intelligent models for prediction of performance can further support energy management. Quality control in every phase has to ensure the interoperability and smooth communication of the various components. The ultimate goal is reliable, high-quality data collection that is the basis for performance assessment and verification. This is imperative when measuring and verifying a community’s performance with multiple data sources. Post-occupancy quality control has provided invaluable feedback regarding cases of lost communication and missing data (Table 9.5). In the ZERO-PLUS communities, missing data occurrences were recorded due to system communication disruptions and sensor malfunction. Sensor malfunction was related to the faulty reading of the measurements. Communication disruption was attributed to Internet connection problems, electric power disruption, or individual component updates. Having a quality control mechanism allows the timely identification of the problem source and immediate appropriate mitigation actions. The COVID19 lockdown caused a period of lost data spanning from mid-February to midJuly 2020 in one of the pilots, where technical assistance could not attend to the problem. Indeed, not all issues can be resolved remotely. Keeping a record of missing data occurrences and implementing suitable data imputation procedures have been identified by the partners as useful good practice. 5.3  Involved experts

The M&V framework presupposes close collaboration among the partners throughout the process. This type of collaboration is inherent to an integrated design process and is expected for the design and construction of net-zero energy communities (Mavrigiannaki et al., 2021). An M&V coordinator’s work in collaboration with a rescue team or a rescue person was proven necessary to achieve timely identification and mitigation of monitoring malfunctions in four pilot communities where it was implemented. Such collaboration is recognized as invaluable through the lessons learned.

182  Dionysia Kolokotsa et al. 5.4  Occupant interactions

In planning the M&V for a community project, the involvement of occupants becomes a critical parameter of the M&V planning decisions. Future owners or occupants need to be included in the process and informed about the location of monitoring equipment in their houses and communities to avoid possible objections at a later stage that could cause unexpected changes or delays, as was the case in one of the pilot communities. In the pilots, non-technical user guides, called “welcome packages,” were prepared and handed to the occupants. These documents contained basic information about the technologies and the monitoring equipment installed on the residences and the communities, guidance on accessing the WebGIS platform, and contact details of the rescue team. Finally, considering occupants’ involvement, the monitoring planning was ruled by the necessary provisions of the General Data Protection Regulation (GDPR). 5.5  WebGIS platform

The developed monitoring scheme alongside the WebGIS platform successfully support the measurement and verification of the net-zero and positive-energy communities. The success factor is the use of open protocols providing the freedom of the development team to easily integrate them to the platform. Moreover, open protocols enable the use of different models and manufacturers for the sensors and data acquisition devices to leverage prior knowledge of the community owners, local installers, and supply chain. 5.6  Rescue team

During the operation of the monitoring scheme in the pilot communities, the local rescue team played a crucial role. The role of the rescue team was taken by the community manager. The team undertook the task to address in a time-sensitive manner any issue concerning sensor faults or equipment/technologies faults and provided guidance, clarifications, and support to the occupants. The rescue team was charged also with the responsibility to review the monthly community report. If the deviation between the computed and simulated values of the KPIs is above 15%, the problem identification procedure is initiated. 5.7  Problem Identification Procedure

The problem identification procedure has been designed to provide a step-by-step guide to identify and solve any issue. In case that the measured performance of the case studies is not as expected for a defined period of time, the problem identification procedure should assist the identification of the cause, whether it is due to faulty installation of the technologies, poor performance of the technologies, faulty settings, or occupant intervention.

Monitoring and evaluation of positive-energy communities 183 6 Conclusions The effective implementation of zero- and positive-energy buildings and communities requires a significant amount of data collection for the monitoring of energy and environmental performance as well as for the application of intelligent models for prediction and fault detection. Different types of sensors and monitoring devices should be interconnected to provide valuable results and support the integration of different components and technologies. The M&V framework for netzero and positive-energy communities, followed by the ZERO-PLUS case studies, provides a road map for other case studies as it is scalable and fully replicable. References Ahmad, M. W., Mourshed, M., Mundow, D., Sisinni, M., & Rezgui, Y. (2016). Building energy metering and environmental monitoring – a state-of-the-art review and directions for future research. Energy and Buildings, 120, 85–102. https://doi.org/10.1016/j. enbuild.2016.03.059 Ali, Q., Thaheem, M. J., Ullah, F., & Sepasgozar, S. M. E. (2020). The performance gap in energy-efficient office buildings: How the occupants can help? Energies, 13(6), 1480. https://doi.org/10.3390/en13061480 ASHRAE. (2002). ASHARE Guidelines 14 – Measurement of Energy and Demand Savings (Vol. 8400, pp. 1–165). Atlanta, GA: American Society of Heating, Refrigerating and AirConditioning Engineers, Inc. BACnet. (n.d.). BACnet Website. Bose, M. S. R. K., Sathyendra Kumar, G., & Venkateswarlu, C. (2005). Detection, isolation and reconstruction of faulty sensors using principal component analysis. Indian Journal of Chemical Technology, 12(4), 430–435. BS EN 1434 – Heat meters. (n.d.). EN. Burkhart, M. C., Heo, Y., & Zavala, V. M. (2014). Measurement and verification of building systems under uncertain data: A Gaussian process modeling approach. Energy and Buildings, 75, 189–198. https://doi.org/10.1016/j.enbuild.2014.01.048 Burman, E., Mumovic, D., & Kimpian, J. (2014). Towards measurement and verification of energy performance under the framework of the European directive for energy performance of buildings. Energy, 77, 153–163. https://doi.org/10.1016/j.energy.2014.05.102 Capozzoli, A., Lauro, F., & Khan, I. (2015). Fault detection analysis using data mining techniques for a cluster of smart office buildings. Expert Systems with Applications, 42(9), 4324–4338. https://doi.org/10.1016/j.eswa.2015.01.010 Carpino, C., Loukou, E., Heiselberg, P., & Arcuri, N. (2020). Energy performance gap of a nearly Zero Energy Building (nZEB) in Denmark: The influence of occupancy modelling. Building Research & Information, 1–23. https://doi.org/10.1080/09613218.2019.1 707639 CEN. (2007). EN 15251: Indoor Environmental Input Parameters for Design and Indoor Air Quality, Thermal Environment, Lighting and Acoustics. Brussels: European Committee for Standardization. CEN. (2017). EN ISO 52000–1:2017 – Energy Performance of Buildings – Overarching EPB Assessment – Part 1: General Framework and Procedures. Brussels: European Committee for Standardization. https://www.iso.org/standard/65601.html

184  Dionysia Kolokotsa et al. CEN. (2019). EN 16798–1:2019 – Energy Performance of Buildings – Ventilation for Buildings – Part 1: Indoor Environmental Input Parameters for Design and Assessment of Energy Performance of Buildings Addressing Indoor Air Quality, Thermal Environment, Lighting and Acoustics. Comité Européen de Normalisation (CEN). www.en-standard.eu/ bs-en-16798-1-2019-energy-performance-of-buildings-ventilation-for-buildings-indoorenvironmental-input-parameters-for-design-and-assessment-of-energy-performance-ofbuildings-addressing-indoor-air-quality-thermal-environment-li. Efficiency Valuation Organisation. (n.d.). What is M&V. EU. (2012). Directive 2012/27/EU of the european parliament and of the council. Official Journal of the European Union, 315, 1–56. EU. (2018). Directive 2018/844 of the european parliament and of the council. Official Journal of the European Union, 156, 75–90. EVO. (2016). Core Cconcepts – IPMVP – International Performance Measurement and Verification Protocol. Washington, DC: EVO. Fanger, P. (1970). Thermal Comfort: Analysis and Applications in Environmental Engineering. www.cabdirect.org/abstracts/19722700268.html FEMP. (2015). M&V Guidelines: Measurement and Verification for Performance-Based Contracts Version 4.0 (Issue November). US Department of Energy. Gallagher, C. V., Bruton, K., Leahy, K., & O’Sullivan, D. T. J. (2018). The suitability of machine learning to minimise uncertainty in the measurement and verification of energy savings. Energy and Buildings, 158, 647–655. https://doi.org/10.1016/j.enbuild. 2017.10.041 Gallagher, C. V., Leahy, K., O’Donovan, P., Bruton, K., & O’Sullivan, D. T. J. (2019). IntelliMaV: A cloud computing measurement and verification 2.0 application for automated, near real-time energy savings quantification and performance deviation detection. Energy and Buildings, 185, 26–38. https://doi.org/10.1016/j.enbuild.2018.12.034 Granderson, J., Price, P. N., Jump, D., Addy, N., & Sohn, M. D. (2015). Automated measurement and verification: Performance of public domain whole-building electric baseline models. Applied Energy, 144, 106–113. https://doi.org/10.1016/j.apenergy.2015. 01.026 Gupta, R., Gregg, M., & Cherian, R. (2019). Developing a new framework to bring consistency and flexibility in evaluating actual building performance. International Journal of Building Pathology and Adaptation, 38(1), 228–255. https://doi.org/10.1108/ IJBPA-04-2019-0032 Heo, Y., & Zavala, V. M. (2012). Gaussian process modeling for measurement and verification of building energy savings. Energy and Buildings, 53, 7–18. https://doi.org/10.1016/j. enbuild.2012.06.024 IEC. (n.d.). IEC 62053–21:2020 | IEC Webstore | Smart Grid, Smart Meter, Smart Energy. IEC. https://webstore.iec.ch/publication/28660 ISO. (2018). ISO 50001:2018 – Energy Management Systems – Requirements with Guidance for Use. ISO. https://www.iso.org/standard/69426.html ISO. (n.d.). ISO – ISO 7726:1998 – Ergonomics of the Thermal Environment – Instruments for Measuring Physical Quantities. ISO. https://www.iso.org/standard/14562.html Kampelis, N., Gobakis, K., Vagias, V., Kolokotsa, D., Standardi, L., Isidori, D., Cristalli, C., Montagnino, F. M., Paredes, F., Muratore, P., Venezia, L., Dracou, Μ. K., Montenon, A., Pyrgou, A., Karlessi, T., & Santamouris, M. (2017). Evaluation of the performance gap in industrial, residential & tertiary near-zero energy buildings. Energy and Buildings, 148. https://doi.org/10.1016/j.enbuild.2017.03.057

Monitoring and evaluation of positive-energy communities 185 Ke, M. T., Yeh, C. H., & Su, C. J. (2017). Cloud computing platform for real-time measurement and verification of energy performance. Applied Energy, 188, 497–507. https://doi. org/10.1016/j.apenergy.2016.12.034 Laaroussi, Y., Bahrar, M., El Mankibi, M., Draoui, A., & Si-Larbi, A. (2020). Occupant presence and behavior: A major issue for building energy performance simulation and assessment. Sustainable Cities and Society, 63, 102420. https://doi.org/10.1016/j. scs.2020.102420 Lee, D., & Cheng, C. C. (2016). Energy savings by energy management systems: A review. In Renewable and Sustainable Energy Reviews (Vol. 56, pp. 760–777). Elsevier. https:// doi.org/10.1016/j.rser.2015.11.067 Mavrigiannaki, A., Pignatta, G., Assimakopoulos, M., Isaac, M., Gupta, R., Kolokotsa, D., Laskari, M., Saliari, M., Meir, I. A., & Isaac, S. (2021). Examining the benefits and barriers for the implementation of net zero energy settlements. Energy and Buildings, 230. https://doi.org/10.1016/j.enbuild.2020.110564 Napolitano, A., Noris, F., & Lollini, R. (2013). Measurement and verification protocol for net zero energy buildings. IEA SHC/ECBS Task 40/Annex, 52, 1–96. https://www.iea-shc. org/data/sites/1/publications/STA-MV-protocol-for-Net-ZEBs-Final.pdf Ni, K., Srivastava, M., Ramanathan, N., Chehade, M. N. H., Balzano, L., Nair, S., Zahedi, S., Kohler, E., Pottie, G., & Hansen, M. (2009). Sensor network data fault types. ACM Transactions on Sensor Networks, 5(3), 1–29. https://doi.org/10.1145/1525856. 1525863 Ole Fanger, P., & Toftum, J. (2002). Extension of the PMV model to non-air-conditioned buildings in warm climates. Energy and Buildings, 34(6), 533–536. https://doi. org/10.1016/S0378-7788(02)00003-8 Peeters, L., de Dear, R., Hensen, J., & D’haeseleer, W. (2009). Thermal comfort in residential buildings: Comfort values and scales for building energy simulation. Applied Energy, 86(5), 772–780. Pioppi, B., Piselli, C., Crisanti, C., & Pisello, A. L. (2020). Human-centric green building design: The energy saving potential of occupants’ behaviour enhancement in the office environment. Journal of Building Performance Simulation, 13(6), 621–644. https://doi. org/10.1080/19401493.2020.1810321 Piselli, C., Di Grazia, M., & Pisello, A. L. (2020). Combined effect of outdoor microclimate boundary conditions on air conditioning system’s efficiency and building energy demand in net zero energy settlements. Sustainability, 12(15), 6056. https://doi.org/10.3390/ su12156056 USGBC. (n.d.). LEED v4.1. Walter, T., Price, P. N., & Sohn, M. D. (2014). Uncertainty estimation improves energy measurement and verification procedures. Applied Energy, 130, 230–236. https://doi. org/10.1016/j.apenergy.2014.05.030 Wang, S. (2016). Making buildings smarter, grid-friendly, and responsive to smart grids. Science and Technology for the Built Environment, 22(6), 629–632. https://doi.org/10.10 80/23744731.2016.1200888 Xia, X., & Zhang, J. (2013). Mathematical description for the measurement and verification of energy efficiency improvement. Applied Energy, 111, 247–256. https://doi. org/10.1016/j.apenergy.2013.04.063 Ye, X., & Xia, X. (2016). Optimal metering plan for measurement and verification on a lighting case study. Energy, 95, 580–592. https://doi.org/10.1016/j.energy.2015. 11.077

186  Dionysia Kolokotsa et al. Zhang, Y. U., Bingham, C., Gallimore, M., Yang, Z., & Stewart, J. (2013). Applied sensor fault detection, identification and data reconstruction based on PCA and SOMNN for industrial systems. 12th WSEAS International Conference on Applications of Electrical Engineering, 38–43. Zmeureanu, R., & Vandenbroucke, H. (2015). Use of trend data from BEMS for the ongoing commissioning of HVAC systems. Energy Procedia, 78, 2415–2420. https://doi. org/10.1016/j.egypro.2015.11.207

10 Post-occupancy evaluation: the missing link Isaac Meir

1

Introduction

Post-occupancy evaluation (POE) is a very broad platform for the documentation, analysis, and study of the actual interaction between user and project, be it a cluster, a building, or just a building system. As such, POE is based on surveys, monitoring, and questionnaires, which must be cross-analyzed to allow the understanding of subjective reactions to objective conditions (Meir et al., 2009). Thus, POE depends on access to and cooperation of the project user. This is not selfevident, as POE activities may be perceived as intrusive and a nuisance, especially when surveys and interviews are repeated over time to map the project–user nexus during different parts of the year, under different conditions. Since this process involves people as study subjects, privacy and personal data protection are inherently connected with POE. This, though, is not enough. The cooperation of the project user depends on their being properly informed on the aims and targets, the tools and methods employed, and their understanding of the implications of such work for their well-being (e.g., enhancing usability, promoting better IEQ), and even potential financial benefits (e.g., savings resulting from properly operating project and systems). The ZERO-PLUS project was even more complex than usual POEs. It spread over four countries with different climatic regimes, involved different types of clusters, buildings, building user groups, local project teams, and an array of other issues which are described hereon. It therefore presented logistical and operational challenges, as well as such that implied comparability of data collected and conclusions reached. Suffice it to say that this module of the project – the last link in the chain – used weather and building IEQ data collected in each project, which were remotely collected, transmitted, analyzed, and stored; surveys undertaken on each site and analyzed by the project’s POE leader; while all this had to be authorized and endorsed by the ethics supervising committee of each of the institutions involved in the different project partner countries. Another unexpected parameter was the COVID-19 pandemic, which complicated matters in ways to be detailed later (Mavrigiannaki et al., 2021; Meir et al., 2019). Due to the project’s nature and size, this module covered a limited number of units, building users, and thus also survey questionnaires; therefore, it may not DOI: 10.1201/9781003267171-16

188  Isaac Meir be considered statistically significant. Nevertheless, it highlights issues potentially inherent to similar POE surveys and flushes out several possible corrections for future consideration. 2 POE tools and methods POE is a multi-purpose, multi-level methodology. It allows the understanding of the interface and interactions between building and user; helps flush out and characterize potential barriers, be they building, technical, or behavioral; identifies building use specific attributes and how these affect overall satisfaction with the building and its systems; helps characterize IEQ from the building user’s point of view; and helps point at potential corrective measures and improvements toward the specific building–user nexus, as well as future design. To reach such understandings, surveyors need to identify physical, cultural, and behavioral attributes and peculiarities of the building user, among them age, gender, health, education, occupation, attire, and even hours of the day a specific tenant uses the specific building unit, and tasks they perform there and then. All these may affect the individual’s perception of their indoor environment and need to be considered under changing conditions – hours of the day, sunny or cloudy, seasons of the year – as described in the POE protocol flow chart in Figure 10.1, which was prepared as the basis for this POE study. 2.1  Privacy and data protection

This POE was conducted as an integral part of the ZERO-PLUS project. Toward this end, relevant procedures, protocols, and documents were planned and prepared right from the beginning. These started by obtaining ethics approval, authorization, and permit to conduct research involving humans. Due to the complexity of the specific project, such approval was obtained by the POE module leader, Ben-Gurion University of the Negev (BGU), from its Human Subjects Research Committee (HSRC). Similarly, approvals were obtained by the project leading partner, University of Athens (UOA), and each of the national teams conducting the surveys in each of the four case study countries (Cyprus, France, Italy, UK). POE involves the collection of both monitored data and surveys based on questionnaires, interviews, observations, whereas the ethical part of the latter was addressed through the HSRC, ensuring the collaboration of the building user was essential. A “welcome package” (WeP) was prepared in all four languages of the case studies (English, French, Greek, Italian), detailing the specific design and operation features and advantages of each case study. An informed consent form (ICF) accompanied each WeP, explaining the purpose and attributes of the ZERO-PLUS project case study, the data to be collected, and the purpose for their collection, ways in which the survey shall be conducted, protection of privacy and personal data, and the right of the building user not to agree to participate, or decide to withdraw at any given moment, having the right to ask that all previously

Post-occupancy evaluation: the missing link 189

Figure 10.1  POE protocol.

collected data be shredded from all storage banks and devices if the building users so desire. 2.2  Questionnaires

To ensure building users would understand the exact purpose and means of conducting the surveys, all translations from the original documents in English were

190  Isaac Meir cross-checked for language, cultural, and other peculiarities and specificities (e.g., levels of education to fit the French education system, Greek colloquialisms befitting Cypriot Greek, or occupation to accommodate the Cyprus case study, which changed in nature, as described later). So were the questionnaires. Questionnaires included annotations to those of the questions which might be perceived as intrusive, too personal, or the purpose of which might be considered improper. Thus, when asked to state their gender, interviewees can read the purpose: “understanding potential differences in thermal comfort”; or next to questions on education (number of years) and occupation, they can read the reason such questions are asked: “building/system usability.” If a building system can be operated only by people with a technical background, the system design needs to be changed and adapted to allow broader usability. Other questions might be perceived as intrusive, for example: If not born in this country, how long have you been living here? The purpose of this question is stated as “acclimatization.” Another asks: Health – are you usually healthy, or do you suffer of some chronic condition? The purpose for asking so personal a question is stated as “potential differences in thermal and visual comfort.” Questionnaires were cross-checked by, and clearance was obtained from, the Human Subjects Research Committees (HSRC) of BGU (POE leader), UOA (project leader), and each one of the national teams’ respective HSRCs. 2.3  Administering questionnaires, considerations, and constraints

The original plan was for local teams to administer the questionnaires in person. This has several advantages, among them the ability to explain the purpose of questions which may be unclear to the interviewee, and address any possible concerns (e.g., privacy, personal data protection). A very important parameter in the in-person interviews is the fact that the surveyor can add personal observations to the questionnaire form, for example, indicate on the space’s plan the specific position where the interview takes place. Proximity to a window, for example, may be of interest in deciphering subjective votes of thermal or visual comfort. Spot measurements of temperature, relative humidity, light intensity, as well as observations (attire, window door or shutter operation, etc.) may help understand subjective reactions to indoor conditions, identify thermal or light asymmetry, operation/utilization of building details and systems, all of which are important in deciphering answers and votes of building users. To allow higher flexibility with surveys; less-intrusive, more frequent survey schedule; and larger number of responses (especially under varying conditions of weather, time, mood, and activity), additional means to administer the questionnaires were considered. One such obvious platform is an online questionnaire. The Technical University of Crete (TUC), designer and operator of the project’s dashboard and data collection and administration system, opted for LimeSurvey (www.limesurvey.org/), an open-source survey tool. The questionnaires’ text was uploaded in the four different ZERO-PLUS project languages. In theory, this

Post-occupancy evaluation: the missing link 191 would allow to prompt building users by an SMS or other prompting method and encourage them to fill in the questionnaire at times considered critical either by the POE leader or local teams – different hours of the day, specific climatic events, etc. – potentially filling in the questionnaires on a mobile phone. However, this idea was abandoned, both because it was considered rather intrusive in terms of the prompting and because employing an additional survey tool (mobile phone) associated with the questionnaires might involve data protection risks which we were not familiar with or prepared to leave unaddressed. Instead, the survey platform was opened by TUC upon request of one of the local teams, the latter having coordinated survey dates and times with the building users, and closed at the end of the designated period. Access to the data obtained was safeguarded, while only the unit pseudonym-related data were kept in a protected storage, as per obligation. This form of self-administered questionnaires embodies several contingencies. However, developing such a tool proved most appropriate and allowed performing surveys under a different, unexpected contingency – COVID-19 lockdown and subsequent restrictions. Other methods considered included administering questionnaires by phone. This was the method closest to person-to-person interview and turned out to be the most appropriate and useful under COVID-19-related limitations and restrictions. It was chosen and employed by the French team. Considerations, methodologies, other POE survey–related issues have been discussed and addressed in several papers which were consulted before and during the POE part of this project (Meir et al., 2018; Gupta & Kapsali, 2016; Gill et al., 2010; Cena & de Dear, 2001; Luo et al., 2015; de Dear & Brager, 2002; Nicol & Humphreys, 2002; Blandford, 2013; Cohen & Crabtree, 2006; Candido et al., 2015). 2.4  Additional tools and methods – quantitative data monitoring

For the subjective, qualitative replies of the interviewees to make sense, they need to be coupled with quantitative data. These generally include monitoring outdoor and indoor environment conditions, presence, and fenestration operation sensors. Researchers often opt also for spot measurements of conditions where surveys take place. In the ZERO-PLUS case, we originally opted for both, not least since all case studies were designed to be monitored both indoors and outdoors, and spot measurements were considered important for specific issues, for example, thermal or light asymmetry. Unfortunately, COVID-19-related contingencies made on-spot measurements impossible, but at least monitored data were available and helped decipher and understand some of the more intriguing replies. Case study–monitored data were automatically transferred from each case study (Cyprus, France, Italy, UK) to the project data hub (ABB, Italy), from where they were transmitted to TUC (Greece), administrator and operator of the ZERO-PLUS WebGIS Platform (data dashboard and bank), and were eventually made accessible to the POE leader (BGU, Israel) after privacy issues were double-checked.

192  Isaac Meir 3 ZERO-PLUS POE Surveys Within the project’s constraints and limitations, for example, delays in obtaining building permits, and even practical contingencies, the POE module was pushed closer to the end of the project. It was hoped that the four case studies would develop in tandem, but reality proved different. Each case study moved at a different pace. Thus, the POE had to accommodate for shorter periods available before the end of the project; compensate for unexpected delays and contingencies due to COVID-19, for example, inability to conduct in-person interviews; and even already-collected questionnaires being locked away at the offices of the local teams, thus making them inaccessible. Nevertheless, troubleshooting, including interviews over the phone instead of in-person on-site surveys, and/or using the online platforms, allowed the collection of a reasonable number of data and thorough understanding of the issues at hand. Table 10.1 details survey dates, methods used, and numbers of questionnaires collected in each of the case studies. Numbers represent questionnaires, not interviewees, each of whom participated in more than one survey (summer and winter; morning, noon, and evening). A total of 94 questionnaires was collected during the periods of summer 2019 (Italy only) and winter, spring, and summer 2020. Italy yielded most questionnaires (37), with Cyprus following closely (31), then the UK (17), and France (9). Several reasons can explain the differences. 3.1  Who were the interviewees?

Despite the relatively small number of interviewees, male and female, they came from all walks of life and covered a wide range of age groups, education background, occupation, hours spent in the unit, etc. They included higher education graduates, technicians, housewives, clerks, employed, unemployed, and pensioners. Figure 10.2 shows demographic data obtained. Most reported “usually healthy.” The few chronic conditions reported included one cardiovascular, one asthma, and one very specific case. These could be associated with comfort perception or sick building syndrome (SBS) complaints, yet the specific questionnaires showed no correlation. The Italian building users were engaged from the very first moment and reported several habit changes instigated by the understanding of the potential of RES. Personal involvement of the local team of surveyors, already experienced in similar projects, helped smooth out potential worries. The fact surveyors visited the houses in person, took spot measurements, and marked on the building plans the specific location interviews took place also yielded interesting insights on thermal and light asymmetry and use of building details and features to improve IAQ. It would be reasonable to state that this early involvement with the project (Summer 2019) later yielded several complete self-administered questionnaires filled online during the COVID-19 lockdown. The Cyprus case study, due to the delays, had to be changed from single-family houses to an Air Quality Observatory (AQO) hosting a laboratory, office space, and

Post-occupancy evaluation: the missing link 193 Table 10.1 POE surveys per case study, season, number of questionnaires, and way of administering them Country Season

Cyprus

Dates

No. of SelfSurveyor Surveyor Selfquestion- admini- in person by phone admininaires stered stered online

Winter 2020 Spring 2020

Feb. 28 2 Apr. 29 1 May 4 2 May 11–19 7 June 6 1 June 12–18 5 Summer 2020 July 7–15 13 Total 31 France Winter 2020 Feb. 11 2 Feb. 20 1 Spring 2020 May 7 2 May 15 1 Summer 2020 June 30 2 July 8 1 Total 9 Italy Summer 2019 July 23 12 Winter 2020 Feb. 15 12 Summer 2020 July 15 13 Total 37 UK Winter 2020 Feb. 18 4 Spring 2020 June 1–5 9 Summer 2020 July 30–31 4 Aug. 12 Total 17 Grand total 94

2 1 2 1 1

6 5 13 24

7 2 1

3 12 12

2 1 2 1 6

13 13

24 4

9 4

7

4 31

6

13 50

a storage room. For the POE, the research staff using the laboratory and several administrative and faculty staff members of the Cyprus Institute (CYI) completed self-administered questionnaires. By being involved in the specific research, or research work in general, they were well aware of the POE targets, a fact which created a certain commitment. 3.2  What went wrong? Contingencies

One may feel compelled to answer this by saying “everything that might go wrong did.” As briefly mentioned earlier, case study projects were delayed for different

194  Isaac Meir

Figure 10.2  POE demographics.

reasons. In Cyprus, a long process of obtaining a building permit, followed by an exceptionally rainy winter, including landslides, impeded construction and led to the decision to change the project’s site, form, and function. A prefabricated (container) structure was chosen at the CYI campus, on which the alternative technologies were incorporated. The AQO laboratory research and administrative staff participated in the POE. In France, the occupation process was delayed, low Internet access and ownership of computers were reported, and the user of one of the units originally designated for POE eventually declined. The first batch of questionnaires was administered in person, and location details were included. In the UK, issues evolved with the incorporation of the originally specified rigid insulation, and two alternative RES systems, delaying occupation. All these pushed the POE toward the end of the project, causing a revision of the original protocol and its time frame. COVID-19 was the last impediment, due to which in-person interviews could not be conducted. In the Italian case, a monitoring system fault did not respond to remote attempts to restart, had to be manually restarted, and this was postponed due to the lockdown and health concerns. In France, interviews were conducted over the phone. In the UK, the building users had to fill in the online questionnaires prima vista with subsequent complications.

Post-occupancy evaluation: the missing link 195 3.3  What did we learn? Lessons

The ZERO-PLUS project proved to be well received by the building users. Their votes on individual parameters and overall satisfaction ranged mainly between “good” and “very good,” with minor discrepancies. In Cyprus, noise and ventilation got poor marks, but it needs to be stressed that both construction and function of the building were not part of the original plan. Temperature, lighting, odors, and overall satisfaction were mainly between “indifferent” (neutral) and “very good.” In France, satisfaction ranged between “good” and “very good” for all parameters, except “ventilation,” which got two “poor” votes. In Italy, scores were between “good” and “very good” for all parameters, except “ventilation,” which got one “poor” vote. Lastly, in the UK, satisfaction ranged mostly between “good” and “very good” for all parameters. Temperature received one “poor” vote, which, though, should be attributed to the exceptionally high summer temperatures over an unusually long number of consecutive days (Osborn, 2020). Overall satisfaction was mostly “very good.” No significant SBS indications were reported other than cases of fatigue in the Cyprus laboratory, attributed mainly to long hours at work. 4 Discussion and conclusions – reassessing POE in light of the ZERO-PLUS results The major conclusion of the POE module of the ZERO-PLUS project needs to be clearly stated up front: all case studies (with some inherent reservations in the case of the Cyprus one, which should not be attributed to the ZERO-PLUS project) have stood up to the project’s expectations as far as user satisfaction is concerned, both on the individual parameters and the overall satisfaction with the building. The POE part of the ZERO-PLUS project proved quite challenging, as expected and pointed out from the beginning of the project’s activities. Being the last task along the chain of activities, it was expected that delays in the individual case studies implementation would affect the ability to properly carry out the POE tasks as intended. Thus, delayed occupancy of the case studies pushed the beginning of the first surveys from summer 2019 to autumn of the same year, then to winter 2019–2020. The Italian case study was exceptional, having been completed and commissioned as intended, thus enabling the first POE survey to be carried out according to schedule. Building user cooperation was an additional issue which proved problematic. One unit had to be removed from the already-limited inventory of units to be surveyed when the tenant refused to participate (France). COVID-19 brought contingencies that proved challenging. These included preventing local teams from carrying out in situ surveys but also prevented building users from being in the building in the case of Cyprus, which is different from all other case studies. Lack of access to some of the pre-COVID-19 stored questionnaires (Cyprus, France) significantly delayed their study, systematic data tabulation, and parallel data analysis.

196  Isaac Meir Technical failure of monitoring equipment and/or online data transfer (Italy) proved to be an additional barrier. Due to COVID-19 concerns, the rescue team tried to solve the problem by remotely restarting the systems to avoid or limit physically visiting the units and subsequent contact with the tenants. Unfortunately, this proved unsuccessful. From the analysis of the questionnaires, the following may be concluded: • • • • • • •

• • • • •

• • •

POE surveys showed high satisfaction with the ZERO-PLUS case studies. Gender distribution was rather balanced. Age distribution was between 35 and >64, with the majority being >45. Education levels were secondary and above. Occupation included housekeeping, technical, retail, health, and “other.” Country of origin was relevant only in the Cyprus case study. In all other case studies, building users were indigenous, thus acclimatized. Nearly all interviewees reported “usually healthy,” except one chronic cardiovascular condition, one with asthma, and one more with a chronic condition which could affect IEQ perception, yet the specific questionnaires did not indicate related complaints. Satisfaction scores were “good” to “very good.” The “good” to “very good” thermal and acoustic properties of the envelope were stressed by most interviewees (except in Cyprus, as explained earlier). Lighting satisfaction scored highly, indicating the importance of daylighting, and appropriately designed artificial lighting. No significant discrepancies were identified between votes for different hours of the day or seasons of the year, implying good design, detailing, and construction. Information obtained on the operation of building details and systems by the building users showed a very clear preference for operating windows and doors to achieve thermal comfort and improve indoor air quality (IAQ) before operating HVAC. A negligible number of SBS symptoms were reported, usually either during evening surveys or after long hours at work, specific to the Cyprus case study, and two questionnaires identifying occupation as “housekeeping.” RES presence enhanced the building user’s understanding of and adaptation to energy-conserving behavioral patterns. This, though, may have triggered a certain “rebound effect,” albeit marginal.

Based on these insights, we consider the POE results to confirm the high quality of the case studies’ design, detailing, and construction. Nevertheless, considering the series of exceptionally hot summers in recent years, not least the summer of 2020, especially in the UK, all future design urgently needs to address climate change, and future needs for cooling, even in traditionally heating-dominated countries! Accepting POE as today’s missing link, a necessary step toward the improvement of buildings and their usability, some general conclusions are in point, so that

Post-occupancy evaluation: the missing link 197

Figure 10.3 Top left, clockwise: Cyprus, France, Italy, UK: satisfaction with ventilation, temperature, noise, lighting, odors, and overall satisfaction with the building.

future POE projects may be smoothened out, barriers may be prevented or overcome, and failures may be avoided. 4.1 The building user

Obviously, a committed building user is key to a successful POE. The need to obtain multiple subjective responses from each building user for numerous cases (sunny or cloudy days, different hours of the day, seasons of the year, specific weather events, for example, heat and cold waves, storms) implies a willingness on the building user’s part to invest time and effort repeatedly. For this to be feasible, the building user must be appropriately informed and given data and tools to assess personally the importance and value of their investment in the POE, for personal benefit (obtaining thermal and overall comfort from the unit, as well as energy expenditures savings, alongside correction of potential building or system design, operation, and interface issues), and that of future design (more and better energyconserving buildings, ensuring public benefits, for example, cleaner environment, fewer emissions, climate change mitigation). These may be defined as incentives

198  Isaac Meir which research has shown to be effective under certain circumstances (Singer & Ye, 2013; Gabay et al., 2014). Carefully written WePs provided to all building users aimed exactly to achieve this by providing all necessary design, technical, and operational information on the building attributes, systems, and appropriate use. However, when explicitly asked whether such information has brought any changes to interaction with the building and its systems, most interviewees replied negatively. This may mean that the ZERO-PLUS buildings and their systems are user-friendly, and their operation self-evident. Such a conclusion is supported by the relatively high satisfaction scores in all case studies. It may also imply that an intelligent building need not necessarily be complicated and user-alienating. Nevertheless, it would be unfair not to note one positive reply coming from an Italian housewife with technical background, who stated clearly that the WeP has made her change her behavior. We bring the exact translation of her response: I changed my behavior in terms of use of energy for housework and in general. For example, before I used to do the laundry during nighttime to take advantage of the lower energy tariffs, while now I use to do it during the sunniest hours of the day to take advantage of the PV [electricity] production. This is encouraging, as it shows that providing appropriate technologies as an integral part of the project and providing the relevant information about them embody the potential for a significant behavioral change toward a more energy-balanced lifestyle. Not much has been investigated or published on the willingness of individuals to participate in web surveys. Some papers tend to emphasize the linkage between interviewees’ willingness and the reputation of sponsoring body and survey provider (Fang et al., 2012). Others point to a linkage between tenant participation in project-related decision-making and management and willingness to participate in surveys, especially if such facilitate raising concerns (Housing Registrar, 2020). There is an inherent need for both building user and building owner/facility manager to identify the potential in such a feedback process (Benton Pereira et al., 2016). This is a major challenge, especially when dealing with people of varying educational backgrounds, environmental awareness, or commitment to abstract concepts (climate change, energy conservation). “Survey fatigue” caused by multiple prompting should be carefully assessed and addressed (Housing Registrar, 2020; Tourangeau & Plewes, 2013). 4.2  The professional

The commitment of architects, engineers, construction companies, building services providers, and facility managers to educate the public toward this end becomes a major issue in the whole process. A linkage is necessary, the existence of which can only be legally mandated, at least until such processes become self-evident

Post-occupancy evaluation: the missing link 199 common practice. Such preconditions already exist in different countries, considering the obligation to comply with the EPBD and similar directives, standards, bylaws, and legislation. Integration of POE in the commissioning process alongside periodic audits, similar to those expected from gas and other services providers, will root the need to comply with standards (Meir, 1999, 2008, 2015; Meir & Pearlmutter, 2010; Meir et al., 2009). The ability to provide more focused operation and maintenance services is an additional incentive for the building owner and the facility manager as it improves user satisfaction and may well lower costs. 4.3  Improving tools and methods

Here we need to consider several items – questionnaires and the means of administering them, the relevance and importance of surveyors on the ground, and not least, privacy and General Data Protection Regulation (GDPR). 4.3.1 Questionnaire length

An appropriately composed and administered questionnaire can help identify and flush out up to 80% of a building’s positive and/or negative attributes (Bordass & Leaman, 2010; Leaman, 2003; Meir et al., 2018;). This is a general concern with most surveys – the longer the questionnaire, the more reluctant people will be to respond, reluctance becoming all the more pronounced when people are expected to fill in the same questionnaire multiple times (Tourengeau & Plewes, 2013). Personal data seem to be a tedious and unnecessarily imposing part of the questionnaire, which, however, is of importance to the understanding and analysis of the interviewee’s replies and votes. This could be overcome if such details could be safely saved the first time, safely kept, and simply associated with the questionnaires from then on, which, of course, would imply certain elaborate and strict GDPR procedures, depending on the way the survey is conducted, and questionnaires administered. 4.3.2 Questionnaire format and administering

There are different ways to administer questionnaires, and they prescribe their format. A large cohort may be appropriate for an automatic prompting on smartphone, smartwatch, or computer, via SMS, WhatsApp, email, or other, if the respondent is asked to answer a very limited number of questions, usually as a vote on a scale, Likert, or similar (Kitoshi Tanaka et al., 2019; Vellei et al., 2016). Such methods imply a previously collected and organized database on building user attributes, the access of users to relevant tools and platforms, their availability and willingness to reply upon prompting, and most important, a cohort large enough to smooth out outliers, errors, and peculiarities, and an appropriately developed application and replies scrambling system to ensure impersonality (lack of connection between a specific device and the replies/votes), privacy and data protection, and not least, addressing interviewees’ concerns (Chin et al., 2012; Shih et al., 2015). Similar

200  Isaac Meir concerns have been addressed in research publications regarding the use of smartphone application in a residential survey, albeit on a scale considerably larger than that of the ZERO-PLUS project (de Dear et al., 2018). Though such methods and tools carry with them technology and privacy complications, they seem to be the obvious future development, not least as they allow a respondent to grade a specific environment (room, office, class, etc.) at a given moment, thus potentially providing a much broader and detailed assessment of a building and its IEQ (Konis et al., 2020). At the other end of the spectrum lie the traditional questionnaires administered by surveyors in person. These assume direct access to the interviewees at specific times, often several times in the same day, as in the ZERO-PLUS case. Despite being time-consuming and often barred by subjective and objective limitations, such an immediate and personal survey method carries with it several advantages, for example, on-spot measurements flushing out specificities (as in the preliminary POE of the Italian case study), observations on attire, operation of building details and systems, and other specificities which may carry special weight when analyzing the interviewees’ responses and votes. Between these lay the interviews conducted by phone (as in the French case study). Although they lack the ability to add personal observations and on-spot measurements, they nevertheless enable conducting a full survey without omitting specific questions (as experienced in parts of the online completed questionnaires, as in the UK case study). All three tools can and should be considered for use, combined or alternately. A combination of remote prompting and “silent surveyor” – a person only observing and taking notes – may be appropriate for large cohorts. However, for smaller ones, especially those of dwellings, the presence of a surveyor on-site still seems to be important. 4.3.3 Flexibility in times of contingencies

This final note needs to be made here, though we have no appropriate answers at this moment. It relates to the obvious clash between building user privacy calling for prearranged survey time slots and the need to conduct surveys during unexpected events, subject to contingencies. Such may concern specific weather events (heat and cold waves, storms, blackouts disabling building support systems), as well as completely unexpected ones (e.g., the COVID-19 lockdown), which may call for custom-made questionnaires and surveys. Such was the case with a CONTEDIL (Italian team) initiative aimed to investigate the building–user interface and interaction during imposed lockdown. A custom-made questionnaire was prepared, intended to accompany the spring and summer 2020 POE surveys. Unfortunately, this initiative was dropped, for several reasons, including concerns that tenants would refuse to fill in longer questionnaires, which might jeopardize the whole spring and summer surveys. Furthermore, the addition would have to be endorsed by the HSRCs of all involved partners’ relevant authorities. Expanding the questionnaires to address COVID-19-specific constraints was

Post-occupancy evaluation: the missing link 201 considered by the project leader’s data protection officer (DPO) to be outside the spectrum defined in the specific informed consent form, thus implying further potential complications. A better harmonization between the relevant documents may well create the platform for quick and adaptable actions in similar circumstances. It is obvious that adding to a standard questionnaire more specific, custom-made questions may well make the difference between missing vital stimuli and information or troubleshooting in real time (satisfaction with the temperature retainment/conservation during storm/heat wave/power failure), obtaining priceless data for special events (COVID-19 lockdown-related questions, such as opening windows to change the indoor air; symptoms experienced when spending longer than usual periods at home), or identifying an inherent building design, detail, construction, or system problem which needs to be addressed in this case study and/or in future designs. Making POE integral and mandatory will encourage developing appropriate tools and methods. References Benton Pereira, N., Calejo Rodrigues, R., & Fernandes Rocha, P. (2016). Post-occupancy evaluation data support for planning and management of building maintenance plans. Buildings, 6, 45. https://doi.org/10.3390/buildings6040045 Blandford, A. (2013). Semi-structured qualitative studies. In M. Soegaard & R. F. Dam (Eds.), The Encyclopedia of Human-Computer Interaction (2nd ed.). Aarhus: The Interaction Design Foundation. Bordass, B., & Leaman, A. (2010). Design Intent to Reality. Cambridge: IDBE Cambridge, The Usable Buildings Trust. Candido, C., Kim, J., de Dear, R., & Thomas, L. (2015). BOSSA: A multidimensional postoccupancy evaluation tool. Building Research and Information, 44(2), 214–228. Cena, K., & de Dear, R. (2001). Thermal comfort and behavioral strategies in office buildings located in a hot-arid climate. Journal of Thermal Biology, 26, 409–414. Chin, E., Porter Felt, A., Sekar, V., & Wagner, D. (2012). Measuring confidence in smartphone security and privacy. SOUPS ’12: Proceedings of the Eighth Symposium on Usable Privacy and Security, July 2012 Article No. 1, 1–16. Cohen, D., & Crabtree, B. (2006). Semi-structured interviews. Qualitative Research Guidelines Project. Princeton: Robert Wood Johnson Foundation. de Dear, R., & Brager, G. S. (2002). Thermal comfort in naturally ventilated buildings: Revisions to ASHRAE standard 55. Energy and Building, 34, 549–561. de Dear, R., Kim, J., & Parkinson, T. (2018). Residential adaptive comfort in a humid subtropical climate – Sydney Australia. Energy and Buildings, 158(2018), 1296–1305. Fang, J., Wen, C., & Pavur, R. (2012). Participation willingness in web surveys: Exploring effect of sponsoring corporation’s and survey provider’s reputation. Cyberpsychology, Behavior and Social Networking, 15(4), 195–199. Gabay, H., Meir, I. A., Schwartz, M., & Werzberger, E. (2014). Cost-benefit analysis of green buildings: An Israeli office buildings case study. Energy & Buildings, 76, 558–564. Gill, Z. M., Tierney, M. J., Pegg, I. M., & Allan, M. (2010). Low-energy dwellings: The contribution of behaviours to actual performance. Building Research and Information, 38(5), 491–508.

202  Isaac Meir Gupta, R., & Kapsali, M. (2016). Evaluating the ‘as-built’ performance of an eco-housing development in the UK. Building Services Engineering Research & Technology, Special Symposium Issue, Vol. 1, 23. Housing Registrar. (2020). Getting tenants involved: Good practice guide. Housing Registrar, Victoria. Retrieved July 2020. www.housingregistrar.vic.gov.au Konis, K., Blessenohl, S., Kedia, N., & Rahane, V. (2020). TrojanSense, a participatory sensing framework for occupant-aware management of thermal comfort in campus buildings. Building and Environment, 169(2020), 106588. Leaman, A. (2003). Post-occupancy evaluation: Building use studies. Gaia Research Sustainable Construction Continuing Professional Development (CPD) Seminars. Luo, M., de Dear, R., Ji, W., Lin, B., Ouyang, Q., & Zhu, Y. (2015). The dynamics of thermal comfort expectations. Building and Environment, 95, 322–329. Mavrigiannaki, A., Pignatta, G., Assimakopoulos, M. N., Isaac, M., Gupta, R., Kolokotsa, D., Laskari, M., Meir, I. A., & Isaac, S. (2021). Examining the benefits and barriers for the implementation of net zero energy settlements. Energy and Buildings, 230, 110564. Meir, I. A. (1999). Spreading the word: Toward a multiple layer program for information dissemination. In S. Szokolay (Ed.), Sustaining the Future: Energy-Ecology-Architecture: Refereed Papers. Proceedings 16th PLEA International Conference: PLEA International & Department of Architecture, Brisbane, September 22–24 (Vol. 2, pp. 679–686). Brisbane: The University of Queensland. Meir, I. A. (2008). Apology for architecture. In S. Roaf & A. Bairstow (Eds.), The Oxford Conference: A Re-Evaluation of Education in Architecture (pp. 33–36). Southampton, Boston: WIT Press. Meir, I. A. (2015). Green Technologies in Planning and Design vis-à-vis Climatic Uncertainty. Encyclopedia of Energy Engineering and Technology (2nd ed., pp. 796–803). Invited Entry. Boca Raton, FL: Taylor & Francis. Meir, I. A., Garb, Y., Jiao, D., & Cicelsky, A. (2009). Post Occupancy Evaluation (POE): An inevitable step toward sustainability. Advances in Building Energy Research, 3(1), 189–220. Meir, I. A., Isaac, S., Kolokotsa, D., Gobakis, K., & Pignatta, G. (2019). Towards ZECs – A brief note on commissioning and POE within the EU ZeroPlus Settlements. SBE19 Conf. Sustainability in the Built Environment for Climate Mitigation: IOP Conference Series: Earth and Environmental Science, Thessaloniki, October 23–25, Vol. 410, 012038. Meir, I. A., & Pearlmutter, D. (2010). Building for climate change: Planning and design considerations in time of climatic uncertainty. Corrosion Engineering Science & Technology, 45(1), 70–75. Meir, I. A., Schwartz, M., Davara, Y., & Garb, Y. (2018). A window of one’s own. POE of a public office building – the demand for personal control over one’s work space. Building Research and Information, in print. Nicol, J. F., & Humphreys, M. A. (2002). Adaptive thermal comfort and sustainable thermal standards for buildings. Energy and Buildings, 34(6), 563–572. Osborn, S. (2020). UK weather: Temperature tops 44C for sixth day in a row for first time in six decades. Independent, August 12. www.independent.co.uk/news/uk/home-news/ukweather-latest-updates-storms-heavy-rain-a9667651.html last accessed Sept.2020/ Shih, F., Liccardi, I., & Weitzner, D. (2015). CHI ’15: Proceedings of the 33rd Annual ACM Conference on Human Factors in Computing Systems, April 2015, 807–816. Singer, E., & Ye, C. (2013). The use of incentives in surveys. Annals of the American Academy of Political and Social Sciences, 645(1), 112–141.

Post-occupancy evaluation: the missing link 203 Tanaka, K., Wada, K., Kikuchi, T., Kawakami, H., Tanaka, K., & Takai, H. (2019). Study on air-conditioning control system considering individual thermal sensation. IOP Conference Series: Earth and Environmental Science, Vol. 294, 012066. Retrieved July 2020. https://iopscience.iop.org/article/10.1088/1755-1315/294/1/012066/pdf Tourangeau, R., & Plewes, T. J. (2013). Nonresponse in Social Science Surveys: A Research Agenda. Washington, DC: The National Academies Press. Vellei, M., Natarajan, S., Biri, B., Padget, J., & Walker, I. (2016). The effect of real-time context-aware feedback on occupants’ heating behaviour and thermal adaptation. Energy and Buildings, 123(2016), 179–191.

Conclusions, or a more critical rethinking of the project Isaac Meir, Shabtai Isaac, and Gloria Pignatta

Nearly three years have passed since the occupation of the project, the postoccupancy (POE) study, the preparation of the final documents, and their submission to the Horizon 2020 authorities for their assessment and approval. This, then, is a time for retrospection and assessment – how efficient was the process, how reasonable and relevant were the targets, how focused and good was the planning, how successful was the end product, what are the lessons to be learned for future attempts? Following are the points we consider of pivotal importance, as these have emerged from the intensive work on this project. The first is the creation of a multi-disciplinary, committed, interacting team which is not only able but also willing and ready to collaborate from the preparation of the pre-proposal to the completion of the project. This is not a completely new insight. For many years now, researchers and professionals, specifically those involved in sustainability-related projects (e.g., green planning and design), have been saying time and again that the creation of a multi-disciplinary planning and design team and the earliest possible integration of experts and sustainability consultants can and do make the project much more focused on the relevant issues, and not least, minimize potentially added costs stemming from the different methodologies, principles, and practices followed, and the integration of technologies needed for the successful completion of the project. To make this more comprehensible, suffice it to say that in this project, the team dealt from the beginning with questions relating to what is possible, how it may be achieved, what is the technical know-how, and how it needs to be informed by new technologies and materials, including such which were developed especially for the project. It was through the collaborative work of all experts and practitioners involved that appropriate solutions were developed for each one of the case studies, not least for the one which needed to be rethought and replanned anew due to bureaucratic, technical, and even environmental hinderances (Cyprus). The second point stems from here and refers to troubleshooting. Well-thought and thoroughly pre-planned as such projects may be, they are very complex and depend on too many parameters, not least site-specific limitations of by-laws and construction restrictions, accessible technologies, and materials availability, as well as contingencies, be they environmental (e.g., exceptionally rainy winter in Cyprus causing mudslides on the intended site), legal (e.g., lack of legal DOI: 10.1201/9781003267171-17

Conclusions, or a more critical rethinking of the project 205 framework allowing the integration of wind turbines in the British case study), consumer-based (e.g., extensive discussions with the Italian house owners regarding the choice of renewable energy sources (RES) systems to be integrated), or community-oriented (e.g., the French case study, which was intended for tenants who, by definition, might have limited or no access to the Internet, on which some of the project modules were based). Troubleshooting ties naturally into any project, but especially into such that are complex and ambitious as this one. The dashboard developed and applied to allow for a continuous tracking of the project performance had to be based on a robust monitoring system made up of flexible modules (sensors, data collection and transfer, warning systems) which can operate in unison or independently when other parts of the system fail. Furthermore, modules and systems were chosen so that they could be remotely rebooted if need be. All this was coupled with local emergency teams which could, and did, intervene when technical issues evolved with the residential units or their mechanical or monitoring systems. The mere concept of local emergency teams is revolutionary in itself. It implies that there is a long-term commitment between planners and designers, the builders, the technology providers, the owners, the authorities, and the tenants. In a market dominated by “hit-and-run practices,” in which many of the planners, designers, and consultants are overworked and underpaid, where the contractor may have a one-year quality assurance commitment – if any at all – and in which once the building, house, or unit is occupied, they become the tenant’s responsibility, having a support infrastructure and teams is a revolutionary idea. Why this is presented as such has to do, among other considerations, with the ability of projects to provide resilience under duress and during contingencies. One of the major contingencies this project had to face was the COVID-19 pandemic. This slowed down things on various fronts, but more so during the POE module of the project. While emergency teams could not access projects (e.g., in the Italian case study), POE was hindered exceptionally. Originally intended to be carried out by local survey teams which could provide not just on-site completed questionnaires but also personal observations, of vital importance in deciphering part of the replies, the inability to access the projects was a major frustration. In Cyprus, for example, completed questionnaires were kept in an office, which was not accessible under quarantine restrictions. Having anticipated the need for remotely prompted and online-completed surveys, an Internet platform was developed early on, which was operated during the pandemic movement restrictions period. This multiple tools approach proved exceptionally helpful under the circumstances yet suffered several hindrances. Due to personal data and privacy protection protocols, the researchers could not obtain or use tenant phone numbers, which would allow for appropriate prompting. Another restricting issue had to do with limited acquaintance of the user with online surveys, or even limited understanding of some of the survey questions or the process of answering the questions. As a result, this last resort to conducting a POE as per planning yielded a certain percentage of incomplete or useless questionnaires.

206  Isaac Meir, Shabtai Isaac, and Gloria Pignatta This might have been avoided or mitigated, at least partially, had it been anticipated and appropriate tutorials, online or as part of the welcome package, had been provided. Yet the question of what is an appropriate length for an explanatory document is not clear or self-evident. Though the need for a welcome package was obvious, which would present to the tenant the special character, attributes, potential, and operational guidelines of the project, keeping it short was one of the major concerns. To ensure the usability and accuracy of this document, as well as that of the questionnaires, they were both translated into all four project languages – English, French, Italian, and Greek. Furthermore, to ensure their compatibility with each project tenants, their accuracy was double-checked in each of the four languages, often requesting external language- or dialect-specific reading (e.g., Cypriot Greek). What emerged out of the POE proved the responsiveness of many of the tenants (e.g., the Italian case study) to the potential advantages provided by the building and its systems. Given the choice and having been appropriately informed, the tenant may and will operate their building and its systems in ways which will allow to take advantage of energy conservation, preference to operate energy-intensive systems when free electricity is provided by RES systems, and even understanding and a certain forgiveness (as in the forgiveness factor identified through the surveys) when extreme conditions stretch the building’s ability to provide for all expectations. Nevertheless, even this has a limit. One of the surveys included complaints on poor indoor conditions (defined specifically as “stuffy” and “too hot”). Fortunately, these researchers were able to couple subjective preferences with objective monitored data, both indoor and outdoor. What these showed were indeed conditions under which very few – if any – buildings could provide reasonable indoor conditions without support systems, for example, air-conditioning, which is still quite uncommon in many European countries. What this means is that despite all good intentions, planners, designers, consultants, technology providers, construction teams need to start providing buildings designed for “unknown unknowns” – planning for climatic uncertainty and climatic exacerbation, hard to anticipate. This is the only way to promote and ensure community resilience and even survivability. It is our conclusion and hope that planning and design will adopt and internalize the lessons learned through this and parallel studies. It is only through environment and climate awareness, integrative and responsive design, institutional memory, corporate responsibility, and user-oriented production of buildings that the built environment can constrain its ecological and carbon footprint toward an attempt to mitigate a far-reaching and destructive process.

Index

Note: numbers in bold indicate a table. Numbers in italics indicate a figure on the corresponding page ABB 74, 77 – 78, 80, 191 active energy communities in selected Europe 24 adaptation 10 adaptation of building 4, 5, 11, 12 – 13 adaptation strategies 7 ADS see adsorption (ADS) module adsorption chillers 160 adsorption heat 161 – 162; heat exchangers 165 adsorption (ADS) module 124 adsorption rotors 161, 163 adsorption unit 107 Air Quality Observatory (AQO) 102, 104, 108, 192, 194; model calibration and validation 110 – 113; validation of model 112, 113 albedo 5, 99 albedo values 91; high 89 Alexandropoulis, Greece 8 ambient temperature 5, 10 – 11, 89 American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE): 55 (fifty-five) 109; Guideline 14 (fourteen) 104, 110, 112, 169; validation indices method 69 Anerdgy: Roofbot 151, 153, 154 – 159; solar energy system 132 anthropogenic emissions vii, 89 AQO see Air Quality Observatory Arena, L. 6 ARERA see Regulatory Authority for Energy, Networks, and Environment (Autorità di Regolazione per Energia, Reti e Ambiente)

as-built configuration of nZEBs 92 as-built documentation 104 as-built drawings 110, 111 as-built model 38, 57, 64, 69 – 71, 110 as-built parameters 85 as-built projections 87 as-built results 69 – 70, 86, 110; overview of building as-built, characteristics for Italian case study 76, 80, 82; settlement 113; simulations 80 as-built scenarios and simulations 80, 82 as-built target and result 86 as-designed expectation 57, 64 as-designed model 68, 70 – 71, 110 as-designed parameters 85; ZERO-PLUS KPIs 117 as-designed target and result 86 Ascione, F. 6, 98 ASHRAE see American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) BACnet 176 Bâtiment à Energie POSitive, or positiveenergy building (BEPOS) standard 130 Belgium 24 BEMS see building energy management system BEPOS standard (Bâtiment à Energie POSitive, or positive-energy building) 130 biomass system 24, 48 biomass urban heating network 131, 134

208  Index bot-based building design 151 – 159; bot potential in roof design 153 – 154; challenges and potential impacts of 158; mind map 154; roofbot implementation 154 – 157; roof design 152 – 153 BPE see building performance evaluation BRE see Building Research Establishment building budget and reserves vii, 37, 40, 46, 130 building energy management system (BEMS) 49, 53 – 55, 68 – 70; comprehensive system using 168; difficulties of 63; HIVE 54; indoor environment control via 60 – 61; smart capabilities of 168 building-integrated PV (BIPV or biPV) system 8 – 9, 49, 53, 68 building-integrated technologies 78 building performance evaluation (BPE) 49, 50 – 53, 64, 71, 168 – 169 Building Research Establishment (BRE) 65 building thermal energy dynamic simulation see thermal energy dynamic simulation Burch, J. 10 carbon emission 1, 2; levels 111; lowcarbon buildings 45; reduction of 6, 74, 80; see also CO2 emissions carbon emission reduction, computing 116 carbon emission reduction target viii; Greece 116, 117; Italy 72, 74, 86; UK 62 carbon footprint 206 Cardinale, M. 6 Carlisle, N. 2 Castaldo, V. 92 Cavagnoli, Silvia 89 – 100 CEC see citizens’ energy communities CHP see combined heat and power citizens’ energy communities (CEC) 21 – 22 CO2 emissions 20, 81; air quality sensors for 82, 83; concentration 59 – 60; concentration, measuring 52, 180; reduction 6, 9, 47, 87, 98 – 99, 163 Code for Sustainable Homes level 4 standard (CSH4) 47 – 48 coefficient of performance (COP) 78 coefficient of variation of the root-meansquare error (CV[RMSE]) 69, 112 combined heat and power (CHP) 8, 66; solar PV and thermal CHP (CHP/ PV) 49, 53, 68; thermal 49

combined scenario 91, 91, 92, 93, 94, 95, 96, 97, 97 communities: current energy community implementation state in the EU 19 – 30; energy community scheme 20; net-zero and multi-energy 1 – 14 community-level strategies for microclimate mitigation and energy efficiency improvement ix, 89 – 100; building thermal energy dynamic simulation 97 – 98; case study 93; communitylevel analysis and microclimate simulation 90 – 92; community-level to building-level analysis 92 – 93; outdoor microclimate simulation 93 – 97; results 93 – 98 community resilience 206 community-scale initiative 3, 6 concentrated photovoltaic (CPV) systems 134, 144, 149 continuous tracking of the project performance 205 cool scenario 91, 91, 92, 93, 94, 95, 96, 97, 97 corporate responsibility 206 Cotana, Franco 89 – 100 COVID-19 viii; Cypriot case study impacted by 110; Italian case study ZERO-PLUS monitoring period during 82, 86; lost data due to 181, 181; POE ZERO-PLUS project contingencies due to 187, 191 – 192, 194 – 196, 200 – 201, 205; UK case study POE impacted by 53 CPV see concentrated photovoltaic (CPV) systems CREATing cOmmunity eneRgy Systems (CREATORS) project (H2020) 29 CSH4 see Code for Sustainable Homes level 4 standard CV[RMSE] see coefficient of variation of the root-mean-square error Cypriot (Cyprus) case study 102 – 117, 119, 121, 125, 128, 148, 190; adopted technologies 105 – 109; Air Quality Observatory (AQO) 102, 104, 108, 110 – 113, 192, 194; building performance simulation 109 – 114; building permit process 194; consumption statistics 116; cost assessments 116, 117; energy conservation and cost savings summary 116; environmental impact 115 – 117;

Index 209 KPIs 117, 117; objectives and methodology 104 – 105; overview of building parameters 103; poor marks for noise and ventilation 195; transition from individual building to the settlement 114 – 115; troubleshooting 204 – 205 Cyprus 181, 188, 191, 192; POE survey 193, 197 Cyprus Institute 102, 113; Freescoo at 165 – 166 Daggett, Owen 47 – 62 data protection officer (DPO) 201 DEC see desiccant and evaporative (DEC) concept decarbonization 19, 29 dehumidification and dehumidification process 109, 160, 163, 164; comparison among 162 dehumidifying rotors 161 Denmark 23, 24 Derwenthorpe dwellings 47, 49, 53 – 54, 65, 69 desiccant and evaporative (DEC) concept 106, 160, 165 desiccants 161 – 162; liquid (LD) 10; solar 49, 106 Directive 2018/2001/EU (revised Renewable Energy Directive – RED II) 21, 26 – 27 Directive 2019/944/EU (Internal Electricity Market Directive – EMD II) 21 DPO see data protection officer Eco Village, Ithaca 8 ECs see energy communities EE see embodied energy EER see energy efficiency ratio (EER) embodied energy (EE) vii – viii energy communities (ECs) 19 – 21; current energy community implementation state in EU 19 – 30; Luče Community, Slovenia 24, 29; Lugaggia Innovation Community (LIC) 29; Magliamo d’Alpi 28; Schoonschip residential district in Amsterdam, the Netherlands 23 energy efficiency ratio (EER) 78 energy management and control 10 energy modeling of positive-energy dwellings 64 – 71; methodology 64 – 69; results 69 – 70

Energy Performance of Buildings Directive see European Union Energy Performance of Buildings Directive energy recovery ventilation (ERV) 6 energy system fostered today vs. the energy system of yesterday 23 environment and climate awareness 206 EPBD see European Union Energy Performance of Buildings Directive ERV see energy recovery ventilation European Commission 22 European Union: current energy community implementation state in 19 – 30; Directive 2018/2001/ EU (revised Renewable Energy Directive – RED II) 21, 26 – 27; Directive 2019/944/EU (Internal Electricity Market Directive – EMD II) 21 European Union Energy Efficiency Directive 167 European Union Energy Performance of Buildings Directive (EPBD) 34, 167, 199 European Union (EU) Horizon 2020 (H2020) i, ix, 21, 28, 90, 93, 204; CREATORS project 29; project COMETS 23; project COMPILE 24, 29; project NRG2peers 28; project PARITY 29; SCCALE 20 – 30 – 50 project 29 EVA module see evaporative (EVA) module evaporation, of water 162 evaporative cooling: direct and/or indirect 161; solar desiccant 49, 106; see also DEC systems evaporative (EVA) module 125 evaporative systems: water-based 4 extruded polystyrene (XPS) 6, 7, 76 – 77, 78, 78; advanced insulation 49; Fibran 76 – 77, 77, 78, 78, 102 – 106, 165 – 166 EValTech 28 Faakye, O. 6 Fabiani, Claudia 89 – 100 FAE system 144 – 149; HCPV 145 – 148; limitations and future developments 148 – 149; results 148 Fahmy, M. 99 Fanger model 109 Fibran 76 – 77, 77, 78, 78, 102 – 106, 165 – 166; see also extruded polystyrene

210  Index Finocchiaro, Peter 160 – 166 floods 90 fossil fuel 1, 7, 21 – 22 France 24, 181, 191, 192; cancellation of installation of CPV in 134; POE survey 193, 194 – 195, 197; Voreppe 130 – 131, 151 Freescoo HVAC system 148, 160 – 166; applications of 163 – 165; concept of 161 – 163; Cypriot case study 102 – 103, 105, 106 – 107, 107, 109 – 110, 119; Cyprus Institute installation of 165 – 166; design evolution of 126; final design of 128; installation of 129; planning method applied for 121 – 122 Freiburg, Germany: Plus Energy Settlement 6, 8; sustainable urban district of Vauban 6, 8 Garmsiri, S. 9 GDPR see General Data Protection Regulation General Data Protection Regulation (GDPR) 182, 199 geothermal energy 11, 26 geothermal heat pump 8, 9 Germany 23, 24; see also Freiburg GHG see global greenhouse gases global greenhouse gases (GHG) 1, 29, 90, 104 Gompakis, Konstantinos 167 – 183 Google Apps Script 157 Google Docs 157 Google Drive 154 Google Earth 91 Google Form 43 Granarolo dell’Emilia 8, 73, 73, 93, 99 green and greenery: roofs or rooftops 6, 89, 151, 156, 157; urban 4 green building standards 167 green individual behaviors 21 green planning 204 green scenario 91, 91, 92, 93, 94, 95, 96, 97, 97 Gregg, Matt 47 – 62, 64 – 71 Gupta, Rajat 47 – 62, 64 – 71, 168 H2020 see European Union (EU) Horizon 2020 HCPV see IDEA’s HCPV/T system HIVE smart thermostats 52, 54 – 55

Horizon 2020 see European Union (EU) Horizon 2020 (H2020) HVAC see heating, ventilation, and air-conditioning heating, ventilation, and air-conditioning (HVAC) system viii, 6 – 7, 10, 89; innovative or advanced 35, 49, 53; set point temperature 84; smaller 163; thermostat 82, 83; under-floor 78; see also Freescoo IDEA’s HCPV/T system, 102, 105, 107 – 110, 113 – 115; characteristics of 108; Cypriot case study 116 Integrated Design Process (IDP) 168 institutional memory 206 integrative and responsive design 206 in-use data 52 in-use model 64, 69; as-built and 70; as-designed and 71 in-use results 57 in-use stage 87 Isaac, Morna 33 – 46 Isaac, Shabtai vii – ix, 33 – 46, 119 – 129, 130 – 134, 135 – 143, 204 – 206 Italian case study 72 – 87, 188, 191; barriers 86 – 87; building description and occupant profiles 74 – 76; buildingintegrated technologies 76 – 78; design phase 79 – 80; construction phase 81 – 82; long-term monitoring and occupation phase 82 – 85; geographical location and climate 73–methodology 78 – 85; overview 72 – 78; results 85 – 86 Italy 24, 181, 191, 192; Bologna 72, 93, 99; community contracts implemented in 25; energy communities 21, 28; Granarolo dell’Emilia 8, 73, 73, 93, 99; “Milleproroghe” Decree 25 – 26, 30; nZE district 7, 9; NZES 5, 6, 8, 72; pilot installations 148; POE survey 193, 197; Rimini 5, 6; Rome 7, 9; timeline of regulatory evolution 26, 26 Jordan, I. 9 key performance indicators (KPIs): Cypriot case study 117, 117; ZERO-PLUS project 49 – 50, 54, 56 – 57, 65, 68, 70, 117, 117, 173, 179 KNX 82, 176 Koehler, Sven 151 – 159 Kolokotsa, Dionysia 167 – 183

Index 211 Köppen-Geiger international classification 73 KPIs see key performance indicators land use and land cover (LULC) 89 land surface temperature (LST) 89 LD see liquid dessicants Li, D. 89 LIC see Lugaggia Innovation Community Likert scale 199 liquid dessicants (LD) 10 local emergency teams 205 long-term commitment between planners and designers 205 LST see land surface temperature Luče Community, Slovenia 24, 29 Lugaggia Innovation Community (LIC) 29 LULC see land use and land cover M&V see measurement and verification Magliamo d’Alpi 28 Mavrigiannaki, Angeliki 167 – 183 measurement and verification (M&V): framework 170; planning and implementation 180; procedures 171; protocols 170 mechanical extract ventilation (MEV) 47e Meir, Isaac vii – ix, 187 – 201, 204 – 206 MeteoBlue 91 MEV see mechanical extract ventilation microclimate 37, 40, 72, 79 – 82 microclimate mitigation: energy efficiency improvement and 89 – 100, 168; methods 90 – 93; results 93 – 98 microclimate mitigation strategy 4 micro companies 44 microgrid 3, 8, 10, 11, 13; community 23; consortium 29 “Milleproroghe” Decree 25 – 26, 30 Ministry of Economic Development (Ministero dello Sviluppo Economico) (MiSe) 27 MiSE see Ministry of Economic Development (Ministero dello Sviluppo Economico) mitigation 10 Modbus 176 multiple tools approach 205 nearly zero-energy buildings (nZEBs) 90, 92, 98, 151; concept of vii – viii Netherlands 23, 24 net-zero-energy (NZE): concept, NZEB and 2; barriers towards achieving

11; technologies employed toward achieving 10 net-zero-energy buildings (NZEB): concept of 1 – 2; barriers to design and construction of 46; demand for 43; EPBD and 34, 43; expenses of building compared to conventional buildings 34; legal definition of, lack of clarity regarding 42; NZES compared to 3; ZERO-PLUS approach to, benefits of 46, 50 net-zero-energy settlements (NZES) 2 – 14; barriers to uptake of 42 – 43, 44; Cairo 6, 8; concept 3; defining 3; drivers for construction of 43 – 44; existing applications and outcomes 4 – 10; list of further areas to explore 12 – 14; further measures and tools for future NZES 13; Granarolo dell’Emilia 6, 8; Pieria 5; Rimini 5; South Korea 9; Synnefa 8; typology of 3 – 4; UC Davis West Village 5, 7; various components of 4; ZERO-PLUS approach to 33 – 36, 46 net-zero multi-energy community: Siberia 9 NZE see net zero-energy nZEBS see nearly zero-energy buildings NZES see net zero-energy settlements OECD see organization for economic cooperation and development Onishi, A. 89 Onshape CAD system and app 143, 155, 157, 158 – 159 operational energy (OE) vii – viii organization for economic co-operation and development (OECD) vii Pan, Wen 119 – 129 personal data and privacy protection 187 – 188; protocols 205 personal observation 200, 205 photovoltaic (PV): cells 49, 107; concentrated (CPV) 134, 144, 149; energy 26, 131; panels 23, 77, 98, 132; system 25, 28, 105 Pignatta, Gloria vii – ix, 72 – 87, 204 – 206 Pioppi, Benedetta 19 – 30 Piselli, Cristina 19 – 30, 89 – 100 Pisello, Anna Laura 19 – 30, 89 – 100 POE see post-occupancy evaluation Poland 24 Politecnico di Milano 28

212  Index polystyrene see extruded polystyrene polyvinyl chloride (PVC) 6; unplasticized polyvinyl chloride (uPVC) 7 positive energy districts (PEDs) 20 positive-energy dwellings, energy modeling of 64 – 71 post-occupancy evaluation (POE) viii, 38, 41, 78, 187 – 201, 204 – 205, 206; case study results 193; definition of 187; demographics 194; protocol 84, 188, 189; questionnaires 53, 189 – 191; survey 69, 87, 105; tools and methods 188 – 191; ZEROPLUS survey 192 – 195; ZEROPLUS survey results 195 – 201 project PARITY (H2020) 29 PV see photovoltaic PVC see polyvinyl chloride (PVC) quarantine restrictions, Cyprus 205 REC see renewable energy communities recovery heat pump and radiant floor or fan coils, combination of 164, 164 Regulatory Authority for Energy, Networks, and Environment (Autorità di Regolazione per Energia, Reti e Ambiente)(ARERA) 27 renewable energy (RE) 49; decentralized 29; exported 2 renewable energy communities (REC) 21 – 22, 24 renewable energy costs, reduction of 19 renewable energy exchange 24 renewable energy production: EU Directives regarding 19; Directive 2018/2001/EU (revised Renewable Energy Directive – RED II) 21, 26 – 27; Directive 2019/944/ EU (Internal Electricity Market Directive – EMD II) 21 renewable energy sharing 26 renewable energy source see biomass; geothermic; photovoltaic; solar energy; wind energy renewable energy sources (RES) systems 205 renewable energy systems 25 renewable energy technologies and the energy management strategies used in net-zero energy settlements 7 – 10 renewable resources 1

renewables 3, 4, 10; diversified use of 13 RES see renewable energy sources (RES) robust monitoring system made up of flexible modules 205 Romano, P. 99 Roofbot software 151, 154 – 159 Santamouris, Mattheos 1 – 14 Schoonschip residential district in Amsterdam, the Netherlands 23 Siberia 9 Slovena 24 smart grids 148, 168, 173 smart home energy management see BEMS smart monitoring and control systems 4, 13 smartphone 199 – 200 smart roof edge solar energy system 132, 134 smart thermostat see HIVE Sokolnikova, P. 9 solar air-conditioning system 105, 121; Freescoo system 160 – 166 solar collectors 23 solar concentration 108 solar dessicant 106 solar energy ix, 7 – 11; concentrating, with FAE system 144 – 149; diversified use of renewables including 13 solar energy generation 131, 133; wind– solar system combined 134, 136 solar-energy-producing components 35 solar fields 155, 156 solar installation ZERO-PLUS 1 Solarinvent FREESCO HVAC system 108, 121 solar modules 131, 132, 134, 153; dual-technology 131, 132, 134 solar panels 42; raised butterfly 157 solar peak energy 56 solar photovoltaic plant 27 – 28 solar power 22 solar-powered renewable energy generation system 104 solar PV 76, 77, 78 solar PV and thermal CHP (CHP/PV) 49, 53, 68 solar radiation 50, 52, 83, 107, 111; annual global 73; global 81; shading effect of vegetation on 94 solar radiation recording 82

Index 213 solar reflectance capability 91 solar thermal system 106 Sougkakis, V. 7 South Korea 9 Spain 24 Spreen, Brooke 151 – 159 Synnefa, A. 7 – 8 Tabula and Episcope Building Typology Brochure 67 TC see thermal comfort thermal: behavior 112; bypass 51; bridges 51; calculation 65; collectors, PV and solar 8 – 9; conductivity 53; efficiency 37; energy 4, 6, 8, 23; energy dynamic simulation 92, 97 – 98; energy performance 79 – 80, 90; energy sectors 22; energy storage 49; environment 61; geothermal energy 11, 26; IES VE calculation 65; imaging 51, 51, 55; parameters 63 – 64; performance 37 – 38, 50; plant 82; properties 103; resistance 7; storage systems 23; transmittance 51, 69, 81; see also Fibran; Freescoo; Stiferite thermal comfort (TC) 12, 40, 42; EnergyPlus indices 109; HVAC system’s impact on 83; indoor 78, 106; survey 53; ZERO-PLUS approach to 85 thermal energy supply liquid desiccants 10 Thermal Regulation, France 130 thermographic survey 50 thermography 51; infrared 81, 142 troubleshooting 63, 82, 192, 204 – 205 UHI see urban heat island Ullah, Khan Rahmat 1 – 14 United Kingdom (UK) 24, 181; POE survey 192, 193, 197; see also York United Kingdom (UK) case study, ZERO-PLUS dwellings 47 – 63, 64 – 71; delivery 54 – 56; design 53 – 54; energy modeling of positive-energy dwellings 64 – 71; methodology 49 – 53; operation 56 – 61; see also energy modeling of positive-energy dwellings urban carbon footprint reduction 20

urban heat island (UHI) 89 user-oriented production of buildings 206 U-value 38, 41, 50, 62, 66; floors 103, 111; roof 55, 66, 67, 76, 103; tests 81, 141, 142; wall 51, 55, 66, 67, 70, 76, 103; window 66, 68, 76, 103, 111 U-values and air permeability values used for the calibration of the buildings’ models 85, 86 Voreppe 130 – 131, 151 welcome package 39, 42, 84, 182, 188, 206 wind direction 130 wind energy 11, 13, 35 wind and solar energy generation system 133 – 134, 136 wind maps 39 window opening: behavior 60, 61; Hobo 52 windows 5; fill gas 65; glazing, double glazing, triple glazing 6 – 7, 67; g-values 65, 66; height of 125; occupant window opening patterns, to control indoor temperature 61, 69, 196, 201; Ug-values 76; U-values 66, 68, 103, 111 windows/door sensors 55 window size N 177, 178 wind power 26; onshore 27; ownership of 22 Wind/PV 49, 53, 68 WindRail 7, 8, 10, 78 wind speed 81, 82, 83, 92, 94, 180 wind turbines 8 – 10, 24, 49, 204 York, England 7, 9, 47 zero-energy building (ZEB) vii, 151 ZERO-PLUS approach ix, 25, 33; barriers addressed by 34; benefits of 35 – 36; defining 34; detailed description of 39 – 42; drivers and barriers to 42 – 44; elements of 36 – 39; methodology 33 – 46, 102; overview of phases of 37; potential for commercial exploitation of 44 – 46; value proposition of 34 – 35 ZERO-PLUS concept 33 ZERO-PLUS demo house 104, 148; see also Cypriot case study

214  Index ZERO-PLUS dwellings, UK case study 47 – 63, 64 – 71; energy modeling of positive-energy dwellings 64 – 71; delivery 54 – 56; design 53 – 54; methodology 49 – 53; operation 56 – 61 ZERO-PLUS framework 33

ZERO-PLUS project vii, 21, 24 – 25, 28; team viii; see also EU Horizon; Freescoo; POE ZERO-PLUS solar installation 151; see also Voreppe ZinCo GmbH 157