High-performance Buildings Simplified: Designing, Constructing, and Operating Sustainable Commercial Buildings 9781947192324, 9781947192331, 2019019790

Table of contents :
Contents
Section 1: Basics
Chapter 1—Terminology and Concepts
Chapter 2—Defining a High-Performance Building
Chapter 3—Certifications, Standards, Codes, and Guidance
Section 2: Design
Chapter 4—Building Design and Delivery Process
Chapter 5—The Commissioning Process
Chapter 6—Sustainable Sites: Locating the Project
Chapter 7—Water Efficiency and Utilization
Chapter 8—Energy: Conversion, Distribution, and Utilization
Chapter 9—Energy: Sources and Generation
Chapter 10—Indoor Environmental Quality (IEQ)
Section 3: Construction and Operation
Chapter 11—Materials
Chapter 12—Construction and Startup
Chapter 13—Operations and Maintenance
Section 4: Future Trends
Chapter 14—Energy Informatics, Smart Buildings, and Smart Grid
Chapter 15—Resilience in Design and Operation
Chapter 16—Future Trends
Chapter 17—References and Bibliography

Citation preview

Simplifying the Essentials of Sustainable Building Design

With a significant basis in the ASHRAE GreenGuide, now itself in its fifth edition, High-Performance Buildings Simplified introduces readers to the fundamentals of: • Building design and commissioning • Sustainability, including water and energy conservation • Indoor air quality and indoor environmental quality • Materials selection, construction, and operations and maintenance • Energy informatics, smart grid, and resilience • Future trends Each chapter includes a list of industry-standard terms, as well as self-guided and instructor-led exercises. Case studies and more than 30 supplemental files containing additional in-depth information and relevant articles round out the practical content. More than just an introductory text, High-Performance Buildings Simplified is a concise resource for anyone looking to keep the basics of sustainable buildings close at hand.

High-Performance Buildings Simplified

High-Performance Buildings Simplified breaks down the basics of high-performance building design using familiar language and practical exercises. It is perfect for use by engineering students, students from other disciplines, the new engineer just starting out in their career, or anyone interested in resource-efficient and environmentally friendly building principles.

High-Performance Buildings Simplified Designing, Constructing, and Operating Sustainable Commercial Buildings Tom Lawrence • Julia Keen

Lawrence • Keen

ISBN 978-1-947192-32-4 (paperback) ISBN 978-1-947192-33-1 (PDF)

1791 Tullie Circle Atlanta, GA 30329-2305 Telephone: 404-636-8400 (worldwide) www.ashrae.org

Hi-Perf Bldgs Simplified_Cover Spread.indd 1

Product code: 90467

9/19

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High-Performance Buildings Simplified Designing, Constructing, and Operating Sustainable Commercial Buildings

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Tom Lawrence, PhD, PE, LEED AP, is a professor of practice and coordinator for the mechanical engineering degree program at the University of Georgia. He has more than 35 years of professional engineering experience. Before going back for his doctorate in mechanical engineering, he spent approximately 20 of those years in the industry and consulting. Among his many roles of service to ASHRAE, Dr. Lawrence is a Director-at-Large on the ASHRAE Board of Directors; past chair of ASHRAE Technical Committee 2.8, Building Environmental Impact and Sustainability; a member of the committee that wrote ASHRAE Standard 189.1 on highperformance green buildings, and was elected an ASHRAE Fellow. As an ASHRAE Distinguished Lecturer, he gives presentations and workshops on high-performance and smart buildings around the world. Dr. Lawrence is also the chair of the editorial committee that produced the fifth edition of the ASHRAE GreenGuide. Dr. Lawrence has a bachelor’s with highest distinction honors in Environmental Science from Purdue University, a master’s degree in Mechanical Engineering from Oregon State University, and a second master’s degree in Engineering Management from Washington University. He received his doctorate in Mechanical Engineering from Purdue University, with a research topic focused on demand control ventilation. Julia Keen, PhD, PE, BEAP, HDBP, is a professor of Architectural Engineering and Construction Science at Kansas State University with a specialty in HVAC, energy codes, and integrated building design. She has a doctorate in Curriculum and Instruction from Kansas State University, where she also received a Bachelor's and Master's degrees in Architectural Engineering. She also owns her own consulting engineering company Keen Designs, PA. Dr. Keen is an ASHRAE Distinguished Lecturer and was elected an ASHRAE Fellow. She served as an ASHRAE Vice President and Vice Chair of Publication and Education Council and has been deeply involved in ASHRAE course development and delivery.

ASHRAE STAFF

SPECIAL PUBLICATIONS Cindy Sheffield Michaels, Editor James Madison Walker, Managing Editor of Standards Lauren Ramsdell, Associate Editor Mary Bolton, Assistant Editor Michshell Phillips, Senior Editorial Coordinator PUBLISHING SERVICES David Soltis, Group Manager of Electronic Products and Publishing Services Jayne Jackson, Publication Traffic Administrator DIRECTOR OF PUBLICATIONS AND EDUCATION Mark S. Owen

Updates and errata for this publication will be posted on the ASHRAE website at www.ashrae.org/publicationupdates.

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High-Performance Buildings Simplified Designing, Constructing, and Operating Sustainable Commercial Buildings

Atlanta

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ISBN 978-1-947192-32-4 (hardback) ISBN 978-1-947192-33-1 (PDF) 2019 ASHRAE 1791 Tullie Circle, NE Atlanta, GA 30329 www.ashrae.org All rights reserved. Printed in the United States of America Cover design by Laura Haass. ASHRAE is a registered trademark in the U.S. Patent and Trademark Office, owned by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ASHRAE has compiled this publication with care, but ASHRAE has not investigated, and ASHRAE expressly disclaims any duty to investigate, any product, service, process, procedure, design, or the like that may be described herein. The appearance of any technical data or editorial material in this publication does not constitute endorsement, warranty, or guaranty by ASHRAE of any product, service, process, procedure, design, or the like. ASHRAE does not warrant that the information in the publication is free of errors, and ASHRAE does not necessarily agree with any statement or opinion in this publication. The entire risk of the use of any information in this publication is assumed by the user. No part of this book may be reproduced without permission in writing from ASHRAE, except by a reviewer who may quote brief passages or reproduce illustrations in a review with appropriate credit, nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any way or by any means—electronic, photocopying, recording, or other—without permission in writing from ASHRAE. Requests for permission should be submitted at www.ashrae.org/permissions. ____________________________________________ Library of Congress Cataloging-in-Publication Data Names: Lawrence, Tom, 1957- author. | Keen, Julia, 1975- author. Title: High-performance buildings simplified: designing, constructing, and operating sustainable commercial buildings / Tom Lawrence, Ph.D., P.E., LEED-AP, Professor of Practice Professor and Chair, College of Engineering Architectural Engineering & Construction Sciences, University of Georgia, Athens, Georgia, Julia Keen, Ph.D., P.E., BEAP and HDBP Certified Kansas State University, Manhattan, Kansas. Description: Atlanta : ASHRAE, 2019. | Includes bibliographical references. | Summary: "Textbook accompaniment to ASHRAE GreenGuide provides practical instruction, assessments, and case studies for engineering students" -- Provided by publisher. Identifiers: LCCN 2019019790 | ISBN 9781947192324 (hardback: alk. paper) | ISBN 9781947192331 (pdf) Subjects: LCSH: Commercial buildings. | Sustainable buildings. Classification: LCC TH4311 .L39 2019 | DDC 690/.52--dc23 LC record available at https://lccn.loc.gov/2019019790

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Contents Foreword

vii

 Section 1: Basics Chapter 1—Terminology and Concepts  Chapter 2—Defining a High-Performance Building  Chapter 3—Certifications, Standards, Codes, and Guidance 

3 15 23

 Section 2: Design Chapter 4—Building Design and Delivery Process  Chapter 5—The Commissioning Process  Chapter 6—Sustainable Sites: Locating the Building Project  Chapter 7—Water Efficiency and Utilization  Chapter 8—Energy: Conversion, Distribution, and Utilization  Chapter 9—Energy: Sources and Generation  Chapter 10—Indoor Environmental Quality (IEQ) 

37 49 59 75 93 117 141

 Section 3: Construction and Operations Chapter 11—Materials  Chapter 12—Construction and Startup  Chapter 13—Operations and Maintenance 

171 189 199

 Section 4: Future Trends Chapter 14—Energy Informatics, Smart Buildings, and Smart Grid  Chapter 15—Resilience in Design and Operation  Chapter 16—Future Trends  Chapter 17—References and Bibliography  v

217 231 241 249

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Foreword It has been interesting to watch the growth and evolution of the concept of high-performance buildings over the past 20-plus years. Though it started as a niche market with a few committed early adopters, the concept has grown and entered the mainstream. Even the terms have evolved—the discipline originally referred to green buildings, but the term high-performance buildings is now preferred. A high-performance building still focuses on all the key topical areas that one would ascribe to a green building as defined in the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED®) program, but also strives to do so in a cost-competitive manner such that the conventional building market will want to adopt these principles. The consuming public and other building professionals’ representative groups continue to become more aware of the societal need to provide buildings that are more resource-efficient and environmentally compatible. The topics related to high-performance buildings include much more than just energy. They also include carbon footprint, water efficiency, indoor environmental quality, materials and methods used in the building construction, and the operation and maintenance of the building. All of these factors help to maintain highperformance characteristics beyond design and construction. I have taught a course in Sustainable Building Design each year at the University of Georgia since fall 2007. Although it originated in the College of Engineering with a focus on serving engineering undergraduate students, the course is offered to students of all majors and is co-listed with landscape architecture. This was done purposefully for engineering students to gain insight into topics outside of their own technical discipline as well as help students from disciplines outside of engineering learn about the core technical aspects of a high-performance building. It is important that more than just the engineers responsible for the design of building be educated on this topic. Future building owners, government officials, financiers, and others play an important role in driving and supporting decisions targeting high-performance building design. Although the core parts come from an engineering perspective, this book is designed to help instruct and guide students and early career professionals from all disciplines in the principles of highperformance building design, construction, and operation. Some content builds on material from the ASHRAE GreenGuide, fifth edition, released in early 2018 and authored and edited by ASHRAE volunteers. I served as the senior editor for the GreenGuide for the past few editions and have used it in my course for approximately 10 years; however, it is not as well-suited for use as a university-level course textbook. The GreenGuide was written for use by practicing professionals, as opposed to someone learning the basics of the trade; thus, the genesis of this book. While the focus here is on commercial buildings, many other concepts discussed can be generalized to the residential sector. vii

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The book is structured to serve as a guide for a flipped or at least partially flipped course. By this I mean that it is designed to provide concepts and background on topics that would be studied outside of the classroom (or studied on their own by an early career professional), while reserving class time for instructor-lead facilitated discussion. Additional outside-of-class activities, suggested design projects, and learning exercises are another key component of this text. Much of the in-class and outside-of-class exercises are based on ones that I have used in my own classes. We have generally tried to keep the discussions and exercises at an introductory level, but also include some that require a more in-depth background knowledge. Instructors, students, and early career professionals using this book are encouraged to provide feedback and suggestions, and my email address is given below. In particular, suggestions for additional exercises or refinements to the ones presented in this book are very much welcome. Tom Lawrence Athens, GA April 2019 [email protected]

This book references supplemental files that accompany many of the end-of-chapter exercises. These files can be found at www.ashrae.org/HPBSimplified. If the files or information at the link are not accessible, please contact the publisher.

viii

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Section 1: Basics CHAPTERS  • Chapter 1—Terminology and Concepts • Chapter 2—Defining a High-Performance Building • Chapter 3—Certifications, Standards, Codes, and Guidance KEY IDEAS  • Key differences between high-performance buildings and those built to minimal code standards • Contributing factors for defining buildings as high-performance • Key terminology • Comparison of high-performance building certification or rating systems, guidelines, codes, and/or standards

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1

Terminology and Concepts 1.1

COMMON ACRONYMS 

The following is a list of common acronyms used both in this book and in the industry. This is not meant to be an exclusive list, but is instead intended to help you build a foundation for a future career and advance the concept of high-performance buildings in this book. AC AEDGs AFDD AHJ AHU AIA AMV ASHRAE

= = = = = = = =

ASPE AWWA BAS BEAM BEMS Building EQ BIM BMP BoD BOMA BREEAM Btu BUG CALGreen CASBEE CFD CFR CHP (CCHP) CHW

= = = = = = = = = = = = = = = = = = =

Alternating current (electricity) Advanced Energy Design Guides Automated fault detection and diagnostics Authority having jurisdiction Air-handling unit American Institute of Architects Actual mean vote American Society of Heating, Refrigeration and Air Conditioning (but now officially goes by ASHRAE) American Society of Plumbing Engineers American Water Works Association Building automation system Building Environmental Assessment Method Building Energy Management System Building Energy Quotient building information modeling (see additional information below) best management practices (see additional information below) Basis of Design (see additional information below) Building Owners and Managers Association Building Research Establishment Environmental Assessment Method British thermal unit (see additional information below) Backlight, uplight, and glare California Green Building Standards Code Comprehensive Assessment System for Built Environment Efficiency Computational fluid dynamics Current facility requirements Combined (cooling) heat and power system (see additional information below) Chilled water 3

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CIBSE CxP DC DCV DG DOE DR EIA EPA EPACT EPBD EPC EPD ERV ET and ETo EUI (NEUI)

= = = = = = = = = = = = = = = =

GSHP GWp

= =

GWP HRV HVAC IAQ IAQP IBC IBD ICC ICT IECC IEQ IES IgCC/189.1 IMC IoT IPC kW LCA LEED® LED LPD MAS MERV MPC MW

= = = = = = = = = = = = = = = = = = = = = = = = =

Chartered Institution of Building Services Engineers Commissioning provider Direct current (electricity) Demand-controlled ventilation Distributed generation (of electrical energy) U.S. Department of Energy Demand response U.S. Energy Information Agency U.S. Environmental Protection Agency Energy Policy Act (1992) Energy Performance Building Directive (European building energy standard) Energy performance certificate Environmental product declaration (see additional information below) Energy recovery ventilator Evapotranspiration and the reference rate for evapotranspiration Energy use intensity (net energy use intensity) sometimes also called energy utilization index (see additional information below) Ground-source heat pump (see additional information below) Gigawatt peak energy production (for solar photovoltaic [PV] or wind power installed capacity) Global warming potential (of refrigerants or emissions) Heat recovery ventilator Heating, ventilation, and air-conditioning Indoor air quality Indoor air quality procedure International Building Code Integrated building design International Code Council Information and communications technology International Energy Conservation Code Indoor environmental quality Illuminating Engineering Society 2018 International Green Construction Code® Powered by Standard 189.1-2017 International Mechanical Code Internet of Things International Plumbing Code Kilowatts Life-cycle assessment (environmental) Leadership in Energy and Environmental Design® (building certification program) Light emitting diode lighting Lighting power density (in W/ft2 or m2) Multiagent system Minimum efficiency reporting value (for particulate filters) Model predictive control Megawatts

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NAAQS NABERS NPDES O&M ODP OpenADR OPR PMV PPD PUE PV REC SHW SMACNA SRI TAB TES USGBC UVGI VAV VFD VOC VRF VRP

1.2

= = = = = = = = = = = = = = = = = = = = = = = =

5

National Ambient Air Quality Standards National Australian Built Environment Rating System National Pollutant Discharge Elimination System Operations and maintenance Ozone depletion potential (for refrigerants) Open Automated Demand Response Owner's project requirements (for commissioning) Predicted mean vote Predicted percentage dissatisfied Power use effectiveness (for a data center) Photovoltaic system for electricity generation Renewable energy credit Solar hot water Sheet Metal and Air Conditioning Contractors National Association Solar reflective index Testing and balancing Thermal energy storage U.S. Green Building Council Ultraviolet germicidal irradiation Variable air volume Variable-frequency drive Volatile organic compounds Variable refrigerant flow Ventilation rate procedure

BRIEF DEFINITIONS FOR COMMON TERMS AND CONCEPTS 

 Architectural Program The architectural program is a process used in the very early phases of a building project in which questions, such as about how the building will be used or how the overall scope of the project will be designed, are answered. These questions include the types of spaces or rooms needed and how many people are expected in each space; the anticipated flow of people, goods, and services through the building; the overall project timeline (when the first occupancy will happen, and so on) and budget constraints; local specific zoning or other restrictions; and transportation issues to and from the site. The architectural program is the initial overall document that guides the project team to develop the building project design that the owner expects.

 Automated Fault Detection and Diagnostics (AFDD) AFDD serves as a database overlay designed to uncover, report, characterize, and oftentimes correct, system faults with the objective of maximizing ongoing building operational performance.

 Ambient The atmospheric conditions surrounding a room, building, or system.

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 Building Information Modeling (BIM) A process that allows for seamless sharing of information and collaboration between various parties about the design, planned construction, and future management of a building. BIM is a database process that gives the design team the ability to share not only the design details but also other key information on the building, such as construction schedules and costing. In this regard, BIM is more than just the technical details but also a method for the people involved to work together more collaboratively.

 Best Management Practices (BMP) Used in a number of industries and contexts; however, in the built environment, BMP refers to methods that reduce the potential for water pollution and stormwater control. For stormwater management, the BMPs are designed to address both the quantity and quality of the water that runs off the building site. These practices can include structural devices such as impoundments to collect stormwater and nonstructural practices such as landscaping designs. As part of the National Pollutant Discharge Elimination System (NPDES) the U.S. Environmental Protection Agency (EPA) created the “National Menu of Best Management Practices (BMPs) for Stormwater” guide (EPA 2019a).

 Basis of Design (BoD) The documentation prepared in the early design phase that describes key assumptions, technical details, and parameters to be used. It also documents the rationale behind key decisions that were (or will be) made in the design, as well as specifications for key systems and equipment.

 British Thermal Unit (Btu) The fundamental measurement for energy in the English Inch-Pound (I-P) system. One Btu equals the amount of energy needed to raise the temperature of one pound of water one-degree Fahrenheit. The corresponding Système Internationale (SI) unit of measure is the Joule. 1 Btu equals 1055 Joules.

 Centralized versus Decentralized HVAC The primary source of cooling or heating and ventilation airflow in a building. A centralized system concentrates the generation of cooling or heating in a limited number of units and then distributes this thermal conditioning to the various zones within the building. Similarly, with air circulation and ventilation, a centralized system provides the conditioning/ventilation air from a limited number of air-handling units (AHUs) that provide this air to one or more zones throughout the building. A decentralized HVAC has all (or most all) thermal zones conditioned and ventilated via units that are dedicated to that zone; thus, this is generally a larger number of units than if the system were centralized. A classic comparative example might be a hotel. Some hotels may choose to provide the cooling and heating source in a central mechanical plant and provide this to fan coil units at each room (via chilled or hot water): thus, a centralized system. Other hotels may choose for each room to have its own dedicated unit, typically a heat pump that can provide both heating and cooling. Note that hotels often have a centralized exhaust system that exhaust air from the restroom areas of each room.

 Combined Heat and Power System (CHP or CCHP) A set of equipment designed to generate electricity (typically with a gas-fired turbine) and then recover the waste heat in the exhaust gas to provide heat to the building for other uses such as domestic or process hot water. If the heat is also used to generate chilled water through an absorption or adsorption chiller, this would be known as a combined cooling, heat, and power system (CCHP).

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 Commissioning A quality control and assurance process for a building to verify that all systems, equipment, and components of a building are designed, installed, tested, and operated per their specifications and operational requirements expressed by the building owner. This process is often given the acronym Cx.

 Demand Charge A component of the rate tariff set by electrical utilities. It is based on the peak demand (rate of energy usage) a customer draws from the grid.

 Design Team The collection of individuals and companies involved in the design, construction, and delivery of a building project. These include (but are not limited to) the building owner, architect, engineering design team, landscape architects, interior designers, construction managers and contractors, commissioning provider (CxP), and building operators.

 Embodied Energy The quantity of energy that was needed to produce or extract, transport, and install a given material or component in a building. The metric used to quantify this would be in terms of a given amount of energy (Btus or Joules) per unit mass, volume, area, or system component (as appropriate for the particular situation).

 ENERGY STAR® A program created by the EPA that rates various products or buildings based on their energy or water efficiency.

 Environmental Product Declarations (EPD) A standardized method for a manufacturer to share information on the environmental impacts of materials, material systems, and equipment.

 Evapotranspiration (ET) and Reference Evapotranspiration Rate (ETo) ET is the loss of soil water due to transpiration by plants in their photosynthetic processes and from soil evaporation. To estimate the rate of ET from a particular landscaping or agricultural crop, a reference rate of ET is adjusted for local climate and the plants involved. The reference rate, ETo, is the estimated rate of water loss for a well-water, fully covered grass surface 8 to 15 cm (3 to 6 in.) in height that would occur in the local climate and time of year.

 Greenfield, Greyfield and Brownfield Sites A greenfield site for a building project is one in which there has been no previous development or building on that site (at least in the modern record). A greyfield site, in contrast, has been previously built upon or developed and may contain some carryover impervious ground coverings such as asphalt or concrete. A brownfield site is one in which there has been prior development and is known to have, or suspected of having, residual contamination by hazardous substances or pollutants. Depending on the specific classification given to the site, there are different levels of expectations in areas such as managing stormwater and treatment of vegetation for a high-performance building.

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 Greywater The waste water from relatively clean sources such as sinks, baths, showers, and washing processes. The term derived from the general color of the water. Greywater can be a potential alternative source for water to a municipal water supply for reuse in areas like irrigation, toilet flushing, and makeup water for cooling towers. This does not include waste water from toilets or that which may contain harmful contaminants that would make the water unsafe for reuse (this water is commonly termed blackwater).

 Ground-Source Heat Pump (GSHP) Heat pumps use a refrigeration cycle to transfer thermal energy (heat) from a cooler medium to a warmer heat sink. In cooling mode for a building, this is the same as what would commonly be called an air conditioner, whereby heat is transferred from the interior space to a heat sink such as the outdoor air. A GSHP is a configuration for a building HVAC system where instead of using the ambient air as the cooling heat sink and wintertime heating source for a heat pump, water is used to exchange heat with the earth. This heat exchange with the earth (ground) can be done using a buried horizontal piping system or with vertical wells. This concept is illustrated in Figure 1.1.

 Indoor Environmental Quality (IEQ) The overall perception of the conditions within building spaces by the occupants of those spaces. This perception goes beyond the indoor air quality (IAQ) to include items such as the thermal conditions, acoustics, lighting, visual appeal, and view of the outdoors.

(a)

(b)

Figure 1.1 GSHP operation in (a) cooling and (b) heating modes. (EPA 2016)

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 Integrated Building Automation Systems (BASs) Integrated BASs are a smart approach to operations and maintenance (O&M). They integrate building infrastructure systems into a common operations interface, facilitate data visualization and sharing across systems, and serve as a repository of maintenance information and procedures.

 International Code Council (ICC) The ICC is an association that develops model codes and standards for the design and construction process of safe, sustainable, affordable, and resilient structures. All 50 states in the United States, in addition to the District of Columbia, several territories, and several U.S. federal agencies, have adopted ICC codes at the state and/or jurisdictional level.

 2018 International Green Construction Code® Powered by Standard 189.1-2017 The IgCC is a high-performance building code suitable for adoption by states and localities as part of their overall model building code. Starting with the 2018 edition, the technical basis for the IgCC is the requirements of ANSI/ASHRAE/USGBC/IES Standard 189.1. In the United States and Canada, the IgCC is offered by the ICC for adoption by various jurisdictions (ICC 2018a). Outside of these countries, Standard 189.1 is available for use directly or in modified form.

 kWh (or kilowatt-hour) The amount of energy equivalent to one kilowatt consumed for the period of one hour. This is the common metric for measuring electrical energy consumption; 1 kWh = 3412 Btu.

 Life-Cycle Assessment (LCA) A method that provides an analysis of the overall environmental impact of a material, component, or system (such as a building). When done thoroughly, this analysis will consider all stage of the products’ life, from raw material extraction or processing through the manufacture, installation, operation, and ultimately the final end-of-life for that material or system,

 Makeup Water/Air Water/air that is used to replenish or compensate for water/air unintentionally lost via evaporation, leaks, or other means.

 Net Zero (or Nearly Net Zero) Energy Building A (nearly) net zero energy building will have sufficient on-site renewable energy system capacity installed (e.g., solar PV, wind, biofuel harvested on site) such that the energy generated is sufficient to offset the energy consumed by the building. This is measured on an annual basis because it is recognized that at times the building will be consuming more than produced (e.g., at night when no solar PV production is possible), while other times the on-site renewable energy system(s) may produce more than the building is currently consuming.

 Owner’s Project Requirement (OPR) The OPR defines the overarching goals and functional objectives the owner would like to achieve with the building project. This includes how the building will be used and operated.

 Phases of Design There are three distinct phases during the building design process generally recognized in the industry.

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•

•

•

Schematic design. This is the initial stage of the building design, generally when the architect works with the owner (and perhaps the initial representatives of the integrated design team) to determine the rough requirements and goals for this building project. Design development. This is a transitional phase where the design moves from general sketches and ideas to a more solid concept of exactly what the building will look like and the types of systems included. Construction documents. After the architect and owner (with the other key design team members) are satisfied with the concepts put forth in the design development documentation, the design team proceeds with preparation of the construction documents. These are the documents (design drawings, specifications, and so on) that provide the basis for the final construction contracts describing what is expected to be built.

 Plug Loads Energy used by equipment plugged into electrical receptacles within a building. The devices are generally considered portable in that they can be moved and plugged into another outlet in that building or any other building. Plug loads are meant to exclude other electrically powered equipment such as HVAC, lighting, water heating, or other process equipment.

 Predicted Percentage Dissatisfied, Predicted Mean Vote, and Actual Mean Vote (PPD, PMV, and AMV) Terms related to measurements or predictions of the building occupants’ thermal comfort. The predicted mean vote (PMV) has been established as a prediction of the mean values of how the occupants would express the thermal conditions in a building. This has generally been expressed on a seven-point scale—cold, slightly cold, cool, neutral, warm, slightly hot, hot—and is predicted based on local parameters such as the temperature, relative humidity, and air speed in the space. The predicted percentage dissatisfied (PPD) is a numerical relationship based on thermal comfort studies that correlates the overall average PMV with a predicted percentage of people in the space that would say they are dissatisfied with the thermal conditions in the building. A related metric is the AMV. This is a measurement of the overall average of people in a real-world building environment that rate the indoor thermal conditions on the same seven-point thermal comfort scale.

 Prescriptive versus Performance Standards or Codes Building standards or codes are designed to list a set of criteria that the building must achieve or match to meet the intent of the code or standard. Prescriptive criteria state the minimum standard a given component of a building should achieve. Performance standards, on the other hand, focus more on how the building functions (in terms of energy or water consumption, for example). An example of a prescriptive standard is for the minimum efficiency of a hot-water boiler. A performance standard measures the total energy consumption per unit volume or mass of hot water supplied. Similarly, the performance standard for a building should reflect the overall combination of the efficiencies of all components and systems installed in the building.

 Project Team This is the combined collective body of people working together to define, design, build, and ultimately operate a building.

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 Project Delivery Methods • • •

•

Design-bid-build. The traditional linear process whereby the owner first contracts with an architect for the building design, then a contractor to build this design is determined based on bids received. Design-build. A process where the owner contracts for the design and construction of a building up front with a general contractor who then manages the entire process Construction management at risk. A newer method whereby the owner contracts with an architect and a construction contractor up front. The contractor advises during the design process, and once design is complete the construction phase is separately bid out and contracted for Integrated design. Focuses on the design and construction of the building being completed by a collaborative team comprised of the owner, architect, design professionals, and construction contractor(s).

 Smart Hardware Hardware in smart buildings that often possess the algorithms necessary to diagnose defective devices and recalibrate and/or fix those devices.

 Solar Reflective Index (SRI) The SRI is a rating method that expresses how well a material or building product can help mitigate its contribution to the urban heat island (UHI) effect. It combines how much of the incident solar heat is absorbed by the material (versus reflected away), the absorptivity, with how well the materials can radiate any absorbed heat away, and the emissivity. The absorption rate can be generally related to its color or hue; bright or white materials absorb less and reflect away more than dark or black materials. Materials radiate thermal energy based on their temperature and a material property known as the thermal emissivity. Most materials have a thermal emissivity of about the same level, at least in ranges for materials in the normal environment. Thus, for most materials, the SRI is more dependent on the absorptivity of the surface materials than the emissivity values. In general, the SRI values for, say, a newly installed asphalt surface would have an SRI value of 0, a freshly poured concrete surface has a value of 35, and a commercialgrade white or cool roof would have an SRI around 70.

 Testing and Balancing (TAB) An important portion of the start-up and verification of buildings after construction is complete. In essence, all HVAC systems in commercial buildings are designed in theory and installed in place piece by piece. Only after the full system is in place can the fine-tuning of the airflow distribution balance and leak checking occur. This process involves steps such as verifying fan speeds or damper positions, minimum flow and pressure balance, and so on.

 Urban Heat Island (UHI) The concept of the UHI revolves around the idea that the human-built environment contains a number of mechanisms that lead to an urban area being at a higher ambient temperature (the outdoor air temperature around this urban area) than the surrounding rural countryside. This increase in temperature is caused by additional heat energy from human sources, such as air-conditioning unit condensers, as well as absorbed solar energy with the built environment structures. The overall relationship is complicated and somewhat locally dependent on items such as solar intensity and typical concrete formulation.

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1.3

MORE INVOLVED DEFINITIONS OF KEY CONCEPTS 

 EUI—Metric for Building Energy Consumption A common metric to measure energy consumption in a building to compare with other buildings. The EUI is determined by taking the total amount of energy consumed annually within a building divided by the conditioned floor space of that building. In the United States, where the Imperial unit (inch-pounds or I-P) system still predominates, it is expressed in terms of thousands of Btus of energy per square foot of floor area during a 12-month period of time (kBtu/ft2·y), whereas in the SI system this is expressed as kWh/m2·y.

 Source versus Site Energy An important factor in the evaluation of building energy consumption. Site energy describes the amount of energy consumed at the building site; in essence, imagine placing an energy meter at the property boundary to measure the amount of energy brought in for consumption. Even though this energy comes to the site in various forms such as natural gas, electricity, fuel oil, steam, or chilled or hot water, it is possible to express all of these in one common equivalent form. As discussed previously, in the I-P system this is expressed in terms of the total number of Btus, whereas in the SI system this is mostly expressed as kWh. Even though electrical energy is universally measured in terms of kW (the instantaneous usage rate) and kWh (the amount consumed over time), for the determination of the EUI in the I-P unit system these are converted (1 kW equals that rate of 3412 Btu/h). Source energy is the total amount of energy consumed to provide the energy consumed as a whole to operate a building. The clearest example of this is in terms of grid-delivered electricity. Particularly for electricity generated with a fossil-fueled power plant, energy consumed at the plant needs to be determined. A modern fossil-fueled power plant has a thermodynamic efficiency of around 40%, meaning that 2.5 units of energy are consumed to produce 1 unit of electricity. There are additional losses in energy as the electricity is transmitted over distances and converted to different voltage levels, such that only about 30% of that original energy actually becomes useful energy for consumption in a building. The actual conversion factor for site to source energy derived would vary by region, particularly for electricity, based on the overall mix of fuel and generation sources. Generation and/or transmission losses also exist for other energy sources besides electricity. Similar conversions are used to determine the total source energy for the use of district energy supply of steam and chilled or hot water. A table of the national average source energy conversions for the United States is given in a report by the U.S. Department of Energy (DOE 2015), where, for example, the amount of imported electricity from the grid (in kWh) is multiplied by 3.15 to convert to the total source energy consumed. The value for electricity is an overall average value for the United States This information is given in Table 1.1; note that these are overall values suggested but the factors may be somewhat different in each local situation. Although there has been a debate in the industry for several decades about whether site or source energy should be the most common metric, the recent trend is to use source energy: it represents a more accurate representation of energy consumption. Source energy does not solely encompass all energy needed to produce electricity at the used level. If a cradle-to-grave analysis is conducted on source energy, the energy required to remove the fossil fuel from the Earth and to transport it to the generation plant has been ignored. This is important because the consumer needs to realize that electricity is not simply generated at the receptacle within the building from which it is used, but instead there is a tremendous opportunity for mitigating environmental impact simply in the discussion of what energy type is selected to serve a building and its systems.

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Table 1.1: Conversion Factors for Site to Source Energy Based on Energy Type (U.S. Averages) (DOE 2015) Energy Form

Source Energy Conversion Factor, r

Imported electricity

3.15

Exported renewable electricity

3.15

Natural gas

1.09

Fuel oil (1, 2, 3, 4, 5 diesel; kerosene)

1.19

Propane and liquid propane

1.15

Steam

1.45

Hot water

1.35

Chilled water

1.04

Coal or other

1.05

 Building Energy Audits A process that reviews the operations of a building and evaluates its energy consumption with respect to the original design intent or accepted standards for the level of performance based on the building type, climate zone, occupancy patterns, and so on. Identifying opportunities for reducing the energy consumption is the primary intent of energy auditing. There are varying levels of detail and involvement in how energy audits are performed. The simplest is what is referred to as a Level 1 audit, which generally includes a simple walkthrough of the facility and a review of utility bills. A Level 2 audit involves monitoring key systems and equipment for a short period of time and an investigation of the building operations in a high level of detail. Energy conservation measures are identified and estimates are made of the expected energy savings for each measure. Done in sufficient detail, that process allows the building owner and operations team to make informed decisions on what efficiency measures to implement. The most detailed audit type is identified as a Level 3 audit. This is an audit that is detailed enough to allow investment-grade decisions to be made and may include design studies detailing the energy conservation measures that will be done. A Level 3 audit is typically performed as part of an energy performance contract whereby a firm will guarantee certain energy saving amounts or will actually design and implement the energy conservation measures. Using this model, energy cost savings over time are used to pay for the measures implemented. The energy auditing process is outlined in Procedures for Commercial Building Energy Audits (ASHRAE 2011) and ANSI/ASHRAE/IES Standard 100 (ASHRAE 2018a).

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2

Defining a High-Performance Building Reflection Exercise: Stakeholders’ Perspectives Think for a few minutes about the metrics that might be used to define a highperformance building—in other words, how is a high-performance building different than a typical building? Consider this question from not only the types of effects buildings have on the environment, but also take into perspective the various stakeholders involved in a building. The stakeholders may include (but are not necessarily limited to): • • • • • • • •

2.1

A building owner that intends to occupancy some or all of the space in a building A building owner that intends to either resell or lease out a building space Tenants that lease all or portions of the building The building occupants, be they workers in or visitors to commercial spaces or renters/owners of residential spaces in mixed-use developments. The people responsible for operating and maintaining the building People living or working in adjacent or nearby buildings and in the city as a whole Government or building code officials who manage the building permitting process The design team (architects, engineers, and specialty consultants) and construction team members

GREEN, SUSTAINABLE, OR HIGH-PERFORMANCE? 

Many different terms are used in the discussion of building design and performance, both in the design and construction industry as well as by the media and the general public. A few of the most common of these terms include green, sustainable, and high-performance. The difficulty is that the terms are not clearly defined nor are they used with consistency. Often, they are used interchangeably. To help add clarity, these terms are further expanded in the following paragraphs. Green is one of those words that can have many meanings, depending on the circumstances. One of these is the greenery of nature in the flora around us. As a result, it infers a connection to the environment and the impact on nature. Concepts commonly associated with this inference include those related to environmental degradation, such as the carbon foot print or natural resource consumption (water and 15

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materials), waste generation, and pollution. Although these topics are all noble and important, they do not encompass the breadth of considerations that must be accounted for when addressing buildings. Over time, and with evolution into the mainstream thought, the term green has been misused in the marketing of many products. Green, in some instances, has nothing to do with environmental impact but can be as misleading as the color of a label. This has led to the term greenwashing, implying the term green has been abused to the extent that it now has little legitimate meaning. Although green is fine term in the appropriate context and use, this publication will generally refrain from using green for these reasons. Sustainable is also a word that does not have a universally accepted definition. A common definition first appeared in Our Common Future: Sustainable development is development which meets the needs of the present without compromising the ability of future generations to meet their own needs. (World Commission on Environment and Development 1987) This definition reflects the common intent when using this word. Like green, sustainable is primarily focused on environmental impact. This book certainly recognizes and agrees that the environment is a priority, but it is rarely the sole focus when designing, constructing, or operating a building. High-performance is be the preferred term used in this text when discussing buildings. Highperformance is more encompassing then green or sustainable. Minimizing impact on the environment is one component of a high-performance building, but the building must also simultaneously provide a healthy, comfortable indoor environment that is cost effective, not only when first constructed, but over its lifetime. Factors that should also be taken into consideration are the operation, maintenance, and durability of the building. A building designated as high-performance is one that is successful, over its full life cycle, in the following areas: • •

• • • •

Minimizing natural resource consumption Minimizing emissions that negatively impact the global atmosphere, and therefore the indoor environment, especially those related to indoor air quality (IAQ), greenhouse gases, global warming, airborne particulates, or acid rain Optimizing the quality of the indoor environment Minimizing discharge of solid waste and liquid effluents, including demolition and occupant waste, sewer, and stormwater, and the associated infrastructure required to accommodate removal Minimizing negative impacts on the building site Optimizing the integration of the new building project within the overall built and urban environment; a truly high-performance building should not be thought of or considered as in a vacuum, but rather in how it integrates within the overall societal context

This more encompassing definition is important as we consider the potential sacrifices that could be made to achieve success when focused on a single area. If simply concerned about a building’s energy consumption or carbon footprint, one could argue to raise the temperature of a space in the summer months to reduce the amount of air conditioning needed. However, this also consequently results in reduced comfort and in turn sacrificed productivity. A high-performance building addresses the opportunity for energy use while also ensuring the building function (occupant productivity) is not compromised. It should be apparent now that buildings are complicated systems composed of many parts and functions. The design, construction, and operation of a truly high-performance building therefore involves the integration of the work of many disciplines and specialties.

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2.2

17

WHY THIS IS IMPORTANT 

Interest in high-performance buildings has been particularly evident in the concern about energy and water resource consumption, but also includes broader concerns such as indoor environmental and air quality, material use, well-conceived development and planning, and so on. Many countries in the world now have voluntary green building certification systems and/or mandatory codes in some form or another. Organizations devoted to green buildings now exist in most countries. Even as the notion of high-performance design is reaching mainstream acceptance, these organizations continue to promote these concepts by calling the industry and society to action and providing leadership on how to achieve high performance. Advocates for high-performance buildings can cite plenty of reasons why buildings should be designed using these concepts. Though these reasons exist, high-performance designs are still not routinely incorporated into building projects, even with the existence of designers (or design firms) with high-performance and integrated design experience. The main driver of high-performance building design is the motivation of the owner; they are the entity that initiates the creation of a project, the one who pays for it (or who carries the burden of its financing), and the one who has (or has identified) the need to be met by the project. If the owner does not believe that high-performance design is needed, thinks it is unimportant, or thinks it is of secondary importance to other needs, then it will not happen. In addition, recent trends in the industry are moving toward high-performance building practices being made mandatory, either through local adoption of new codes and standards or through organizational policy. These trends are discussed in more detail in the Chapter 3.

2.3

THE TRIPLE BOTTOM LINE: PEOPLE, PROFIT, AND PLANET 

One method for assessing sustainability is through the concept of the triple bottom line (Savitz and Weber 2006). This concept advances the idea that monetary cost is not the only way to value project design options. The triple bottom line concept advocates to include economic, social, and environmental impacts of building design and operational decisions in design evaluation. Others describe this concept as the “three Ps”, or people, profit, and planet. The desire for higher-performing buildings in the past has generally been driven by the recognition that the Earth’s resources are finite and environmental concerns such as climate change, availability of water and materials, and energy consumption are affected by the built environment. This is all good, but we must not forget the other two Ps in this equation, people and profit. It has been noted that, for example, practically any building in the world could be made net zero energy, a term that is defined in detail later, but for now let us take it as a building that generates as much energy as it consumes on site over the course of a year. Any building might well be designed for net zero, but only if there is enough land area available to generate that energy on site and, of course, if sufficient money is available for financing. We must keep in mind that the concept of high-performance buildings will not be sustainable unless the highperformance aspects become cost effective; cost effective meaning that the owners and developers will be willing to invest in those features, or at least not be too upset if the future building codes require high-performance features. Studies of the buildings industry have confirmed a growing recognition that green (or high-performance) concepts can lead to better profitability as well (McGraw-Hill 2018). The final “P” in this process represents the people that will occupy the building. It is for their use and purposes that the building was constructed in the first place. If the building does not meet the needs of the people it is intended for, then what use was it? Put another way, just as any machine or device undergoes extensive thought about the intent and how that device is to be operated, so should the building be considered with respect to the occupants’ needs and indoor environment.

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2.4

COMMITMENT TO HIGH-PERFORMANCE PROJECTS 

High-performance projects require more than a project team with good intentions; they require commitment from the owner and the rest of the project team. The most successful projects incorporating high-performance design are ones with dedicated, proactive owners who are willing to examine (or give the design team the freedom to examine) the entire spectrum of ownership, from design to construction to long-term operation of their facilities. These owners understand that high-performance buildings require more planning, better execution, and better operational procedures, and thus require a firm commitment to changing how building projects are designed, constructed, operated, and maintained to achieve a lower total cost of ownership and lower long-term environmental impact. Implementing high-performance practices could indeed raise the initial design costs associated with a project, particularly compared to a code-minimum building design if not included as a priority at initial design concept meetings. In this context, a code-minimum building is designed to meet the minimum standards set by the building code. For example, imagine a building that is set to meet the bare minimum requirements set by the energy code. First cost is an important issue and is often a stumbling block in moving building design from the code minimum to one that is more truly sustainable. Investing in the initial design budget can often actually reduce overall total design/construction costs if implemented early rather than being added after much of the design is complete.

2.5

HISTORY OF HIGH-PERFORMANCE BUILDINGS 

Prior to the industrial revolution, building efforts were often directed throughout design and construction by a single architect—a method called the master builder model. The master builder alone bore full responsibility for the design and construction of the building, including any engineering required. This model lent itself to a building designed as one system, with the means of providing heat, light, water, and other building services often closely integrated into the architectural elements. This integrated design approach commonly resulted in buildings that were high-performing and sustainable, although that was not the goal of yesteryear’s master builders. Many structures achieved an admirable combination of great longevity in construction, operation, and maintenance. It is interesting to compare the ecological footprint (a concept discussed later in this book) of Roman structures from two millennia ago heated by radiant floors to a twentieth century structure of comparable size, site, and use. In the nineteenth century, as ever more complicated technologies and scientific methods developed, the discipline of engineering building systems and design emerged separate from architecture. This change was not arbitrary or willful, but was rather caused by the increasing complexity of design tools and construction technologies and a burgeoning range of available materials and techniques. This complexity continued to grow throughout the twentieth century and continues today. With the architect transformed from master builder to lead design consultant, most engineering work is performed predominantly as a subcontract to the architect, who in turn was retained by the client (owner, developer, or others). Under the design and delivery approach with the architect as the lead, the architect conceives the shell and interior design concepts first. Only then does the architect turn to rest of the design team: structural engineers; heating, ventilation, airconditioning (HVAC) engineers (with maybe also refrigeration involved); electrical engineers; landscape architects; and other specially consultants such as information technology (IT), and so on. Hand-in-hand with this evolution of the design and delivery method emerged the twentieth century doctrine of buildings over nature, an approach still widely demanded by clients and supplied by architectural and engineering firms. The buildings over nature paradigm does not embrace or take advantage of the surroundings or architectural design synergy, but instead relies on the brute force of the system to enable function. An example of

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19

such a practice is to provide unnecessarily large HVAC systems that are resource-intensive and energyintensive to build, operate, and maintain conditions acceptable for human occupancy instead of taking advantage of many opportunities to integrate architectural elements such as reducing solar load with shading, strategic placement of windows, building orientation, and so on, often because the HVAC engineer is brought into the conversation too late in the design process. Recognizing the inefficiencies of what is the norm today, progress is being made to correct these issues. One approach is the implementation of a new delivery method, the integrated design process. In this system, the design team (architect, engineers, specialty consultants, and the owner) are part of the design process from the very beginning. This is important, as it allows these integrated items to be incorporated in the design from the beginning. Even with an integrated design team to bridge back over the gaps in the traditional design process, a high-performance building with optimally engineered subsystems will not result unless done by professionals with appropriate knowledge and insight.

2.6

WHEN HIGH-PERFORMANCE DESIGN IS APPLICABLE 

Perhaps the obvious rebuttal is, “When is high-performance design not applicable?” However, practicalities do exist in the design process, the funding that the owner has available, or expectations of some of the stakeholders that may interfere with consideration of high-performance design and operation. This book is intended to help overcome these impediments. One recent trend in architecture, especially in the design of smaller buildings, is to invite nature in when conditions are appropriate. This is an alternative to the normal concept prominent during the past century of excluding the outdoor environment by isolating the indoor space and then providing sufficiently powerful mechanical/electrical systems to maintain temperature control and ventilation. These new design concepts present a significant opportunity for engineers today. Design teams who take this approach require fresh and complementary engineering approaches, not tradition-bound design that incorporates extra capacity of the mechanical systems to maintain good indoor environmental conditions. Natural ventilation and hybrid mechanical/natural ventilation, radiant heating, radiant cooling, and solarassisted air conditioning are just a few examples of the new tools with which today’s engineers can use to achieve high performance as well as a more natural indoor environment. Interesting enough, some of these “new” techniques have been well-known for centuries and used around the world. These can be enhanced with capabilities allowed by new technology advancements, better understanding of the physical processes involved and optimum use of their potential effectiveness. Fortunately, there is a great deal of information available about high-performance building design, including this text. Further, tools for understanding and defending engineering decisions in such projects are emerging. For example, a revised ASHRAE thermal comfort standard, ANSI/ASHRAE Standard 55, Thermal Environmental Conditions for Human Occupancy (ASHRAE 2017a), includes an adaptive design method that is more applicable to buildings that interact more freely with the outdoor environment. ASHRAE Standard 55 also accommodates an increasing variety of design solutions intended both to provide comfort and to respect the imperative for sustainable buildings. High-performance engineering aspects in a building project can be provided for their own sake, independent of any client or architect demand. Ideally, the end result is an energy-efficient system that is more robust and provides for a better indoor environment than a cookie-cutter conventional design. The appetite for environmentally conscious engineering must be carefully gaged, and opportunities to educate the design team carefully seized. In this way, engineers can bring greater value to their projects and distinguish themselves from competing individuals and firms.

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2.7

WHY CAN’T ALL BUILDINGS BE HIGH-PERFORMANCE— OR SHOULD THEY? 

This is a good question to which there is no real one right answer. Ideally, all buildings would be designed, constructed, and operated to high-performance standards. Currently, the high-performance criteria is only generally applied to buildings that are large-scale investments or in projects where the owner is a long-term investor (such as a government agency, university, and so on.). Other building projects are focused on lowest cost to construct; these buildings will likely only be built to high-performance standards when society as a whole realizes it is important that these be achieved for reduced energy and water consumption, materials efficiency, and so on. If or when this decision point comes, the building codes process will be the method used to ensure high-performance standards are applied in every building.

Discussion Topics, Exercises, Investigation Study Topics and Assignments For Class Discussion 1. 2. 3. 4.

5. 6. 7.

8.

Is the decision to design a new building to be high-performance an individual issue and decision for the building owner/developer, or does society in general have a role? Are high-performance buildings just a fad that will may well go away in the future? Why or why not? Some have said “the greenest building is one that already exists”: Why would someone be inclined to state that? To what standard should high-performance buildings be held in terms of expense? Should they be expected to cost the same as a conventional building, or would there be a different standard for reference (such as being cost-competitive)? Are high-performance buildings considered now part of the mainstream in the industry, or are they still a niche market (meaning only a few will choose this approach)? What are the barriers preventing every building from being a high-performance building? If a new building were to be planned for this university campus, should it be designed and constructed as a high-performance building? Why or why not? What if this means it will require every student to pay an increased tuition rate or an additional fee? If so, how much would you be willing to pay? Considering the definition of a high-performance building, identify the attributes of the place where you live that conform to meeting these requirements, as well as those areas that fall short.

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In-Class Exercises 1.

2.

3.

Observe and think about the building you are currently in. What features of this building currently contribute to it being a high-performance building? What changes can you recommend to bring this facility closer to meeting the definition of a high-performance building? Imagine yourself as the administrator for a rural school district that has a limited budget. The district needs to replace one school building that has been wiped out by a severe storm (e.g., a tornado). What are some of the considerations to be given to the choice of whether the replacement school building will be designed/built/operated similar to a high-performance building? Spend 5 to 10 minutes thinking about the following key policy and economic issues and questions that affect sustainable building design and practices. We will then break into small discussion groups to share these observations, and then report back to the full class the group’s conclusions. (This also could be done as an outside of class “for further investigation” study). a. What do you think has been the primary driver toward high-performance building practices becoming more mainstream during the past 15 to 20 years? b. What are the key factors preventing further market penetration of highperformance building practices? c. Should some level of high-performance building requirements be made mandatory for all new construction and major renovation projects? If so, how would you propose these be developed and enforced? d. Should there be a mandatory building energy consumption reporting mechanism? (Consider this topic now with what you know to date; we will discuss this issue in more detail in Chapter 13). e. Would you support a student-led demand that any new building on this university campus be certified according to a high-performance building program such as the Leadership in Energy and Environmental Design® (LEED®) Green Building Rating System? f. Some states are rolling back their building energy code requirements to older standards (i.e., becoming less efficient). What do you think the key drivers influencing this push are? g. Is there a changing paradigm in the United States concerning acceptance of high-performance buildings and a focus on sustainability overall? If so, which way is it changing and why? h. Some have talked about the need to future-proof buildings; that is, have them be readily adaptable to future conditions. What aspects need consideration for future proofing and how might they that be accomplished?

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For Further Investigation and Study 1.

Research the growth in high-performance (or green) buildings in the United States. How does this compare with the growth in other regions of the world? Select two of the following regions to conduct this comparison. a. b. c. d. e.

2.

Europe Australasia India South America Africa

Do high-performance buildings command a premium price in terms of building selling price or lease rates? If so, by roughly how much? If not, why do you think they do not? Provide the source reference in addition to your answer.

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3

Certifications, Standards, Codes, and Guidance 3.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: • • • • • • • • •

Advanced Energy Design Guides (AEDG) Authority having jurisdiction (AHJ) Building Research Establishment Environmental Assessment Method (BREEAM) California Green Building Standards Code (CALGreen) Chartered Institution of Building Services Engineers (CIBSE) Energy Performance Building Directive (EPBD) International Energy Conservation Code (IECC) International Green Construction Code (IgCC) Leadership in Energy and Environmental Design (LEED)

Rapid growth of interest in high-performance buildings has occurred over the past two decades, with a corresponding growth in the number, depth, and breadth of available resources to guide the practicing professionals. There are several types of mechanisms that exist to encourage (or require) highperformance building design. Each has their own purpose and targeted goals: •

•

•

•

Minimum Building Standards and Codes. These codes set minimum criteria for how buildings are designed and their equipment and systems are installed. They, in essence, define the “least bad” the building can be and still legally be occupied. High-Performance Building Codes. These are more progressive building codes that extend the minimum design criteria to include high-performance features. The International Green Construction Code® Powered by Standard 189.1-2017 (IgCC/189.1 [ICC 2018a]) is one example. Building Certification, Rating, or Labeling Programs. These types of programs are designed to recognize buildings that meet criteria for higher-performance buildings. They are (generally) not required, but are voluntary programs the owner and design team can decide whether to pursue. A prime example would be the U.S Green Building Council’s Leadership in Energy and Environmental Design (LEED) program. Guidelines. This category includes documents that provide general guidance to the design team but that are generally not legally enforceable nor used to rate the overall building design and performance. 23

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This chapter provides a brief summary of each type of resource and how they might be used to advance high-performance buildings.

3.2

MINIMUM BUILDING STANDARDS AND CODES 

While the building permit and code compliance process varies widely across the globe, there are some common factors. First, a minimum set of criteria must be established. These criteria can be prescriptive or performance-based in nature. Prescriptive criteria are specific items and/or methods required to demonstrate compliance, while performance criteria specify a goal to reached and require more effort on the part of the designer to show the goal has been met. Prescriptive criteria can be thought of as a checklist that to be used in design. Alternatively, performance criteria can be considered as a threshold that needs to be met or exceeded; compliance verification of that performance is done using methods such as building energy simulation modeling.

 The Building Permitting Process and Code Enforcement While the basic process varies between local jurisdictions, there are some common parameters that exist. A building owner will generally apply for the approval to build a building with the local authority, generally referred to as the authority having jurisdiction (AHJ). Some jurisdictions may require approval of the building proposal through a local planning agency as well. The AHJ will review the building plans submitted for compliance with the current building codes. In the United States, each state adopts its version of the building code. There are overarching codes (such as the International Building Code [IBC]), and then codes that deal with specific aspects, such as the International Mechanical Code (IMC), the International Plumbing Code (IPC), and the International Energy Conservation Code (IECC). The AHJ will conduct inspections of the building and equipment that is being installed during the construction process. Once the AHJ is satisfied that the building and its systems meet the requirements of all applicable codes, a certificate of occupancy (or other similar document) is issued that allows for the owner to legally occupy the building.

 The Basis for Building Codes The original reason for establishing building codes was to verify that a building was safe to occupy. The original drivers were catastrophic fires and structural failures (particularly in the late 1800s and early 1900s) that led people to create standards that now are the basis of the building codes. These codes are written in legally enforceable language and enforced by local agencies. They set criteria for buildings in areas such as structural design, electrical design, fire safety, plumbing, HVAC, and energy performance. As such, these codes do not define high performance, but rather the minimum performance allowed by law and enforced by the local jurisdictional authority.

 Energy Codes The closest that minimum codes come to defining a high-performance building is in energy codes. The concept of minimizing energy consumption and maximizing building performance has been a priority for many years. Its importance became evident in the 1970s when the price of energy escalated quickly as a result of the Organization of Arab Petroleum Exporting Countries (OPEC) declaring an oil embargo. This significant change in energy pricing made building owners acutely aware of the affect energy costs had on their bottom line and profits. As a result, a need surfaced to help building designers design more energy-efficient buildings. The first of these documents was ASHRAE Standard 90-1975. This document eventually evolved to become ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, which is recognized as the basis of most energy codes adopted today. This document continues to be updated every three years, matching the building code update cycle in the United States (ASHRAE 2016d).

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Standard 90.1 has been written to conform to a number of constraints. Because it is a standard, its scope is strictly defined, meaning in this case that it only considers content specifically related to building energy use. It does not address water consumption, refrigerants’ impact on the environment, or the large number of other factors in a high-performance building. The content areas include energy use of the building envelope (the exterior shell of the building, such as the walls, windows and roof), lighting, HVAC, and service water. This standard is intended to define the minimum energy performance considered acceptable within the context of current society. A building that meets exactly the criteria defined in this document is therefore considered the least efficient building that can be built and still given an occupancy permit. The language used in this standard, and the format used, is such that it can be adopted as a legally enforceable code. The design criteria contained is required to show that it pays for itself in a life-cycle cost analysis. It is important to many owners and jurisdictions (such as cities, counties, states, and federal entities) that adopt this document into law that the criteria are not economically burdensome (ASHRAE 2016d). Not all jurisdictions have elected to adopt Standard 90.1 but have instead chosen to adopt another version of an energy code or create and maintain their own energy codes. The most common alternative code is the IECC, produced by the International Code Council (ICC). This document is created with close collaboration with ASHRAE to ensure the content does not conflict. The content is so similar that the IECC states in their document that Standard 90.1 is an alternative compliance path.

3.3

HIGH-PERFORMANCE BUILDING STANDARDS AND CODES 

There is a defined need to have standards and codes that reflect a much better level of performance than just the code minimum, and for criteria that extend into areas beyond energy efficiency. In the area of energy efficiency, a number of U.S. states and jurisdictions have surpassed minimum energy code requirements. Major cities across the United States that have taken exceptional steps towards increasing the energy efficiency of their buildings include Chicago, New York, San Francisco, and Washington, D.C. An overview of international building energy efficiency policies (e.g., codes, incentives, and labels, for all types of buildings including mandatory, model code and voluntary programs) is maintained by the International Energy Agency (IEA) in a publicly available database (IEA 2019). However, as should be apparent by now, high performance in a building involves a host of other topics. To address this need, the industry started to create standards that could be adopted into the building codes starting around 2005. The remaining part of this section outlines the history of this phenomenon in the United States.

 Standard 189.1 and the IgCC In 2006, ASHRAE, in conjunction with U.S. Green Building Council (USGBC) and the Illuminating Engineering Society (IES), began a process to create a standard that would address a growing need within the industry for a code-language document for high-performance buildings. ANSI/ASHRAE/USGBC/IES Standard 189.1, Standard for the Design of High-Performance Green Buildings, was developed to be suitable for adoption into the model building codes. It was initially released in 2009. The document is different than Standard 90.1 in that it covers much more than just energy—it covers site sustainability, water use, indoor environmental quality (IEQ), environmental impact of materials and resources, the construction process, and ultimately the building operation. This standard built upon other key ASHRAE standards and adopted these with modifications, when considered necessary, to have a document that defines what a high-performance building really is. Besides the expanded topical content, Standard 189.1 was different than Standard 90.1 in that it is progressive code and it does not require a financial payback (although costs are a consideration). The idea of a progressive code is that it asks for performance beyond the minimum levels and that not all the items contained in it will necessarily pay for them-

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selves when implemented. The payback in this case is seen as more than monetary, but rather the saving provided in social and environmental expense. This standard is not targeted for each and every building project, but rather for high-performance building projects. This document was intended to help the perceived gap in the evolving building codes in the area of high-performance buildings, as locales began to adopt high-performance building design as a requirement. Besides the obvious intent of providing a vehicle for adoption into building codes, this standard may also be used by developers, corporations, universities, or governmental agencies to set requirements for their own building projects, even if they are not required by their local jurisdictions. During the development period of Standard 189.1, which took approximately three and a half years, the ICC also worked to create its own version of a high-performance building code. The IgCC was created for the same reasons as Standard 189.1—to provide a tool in the market for adoption of high-performance standards in all topical areas. Similar to the minimum energy performance codes, ASHRAE and the ICC worked together such that Standard 189.1 was recognized as an alternative compliance path to the equivalent ICC code (the IgCC). In this case, Standard 189.1 was included as an appendix to the IgCC. After several years of a dual set of standards, ASHRAE and the ICC agreed that the two should be merged. Starting with the 2018 code cycle, ASHRAE is the subject matter expert for technical content of high-performance building codes while the ICC is responsible for the administrative provisions in the 2018 IgCC. The 2018 version of the IgCC/189.1 reflects this merger (ICC 2018a). In in the United States, building codes are, in general, adopted for use by each state and local jurisdictions incorporate those into their local ordinances. An illustration of the status for adoption of the 2015 IgCC is given in Figure 3.1—it is important to note it takes a while after the release of new editions of the codes for them to be adopted).

Figure 3.1. Adoption of the IgCC in the United States as of December 2018 (ICC 2018b)

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 Other Jurisdictions and Codes In 2010, California became the first state in the United States to adopt a high-performance building code, the California Green Building Standards Code or CALGreen. California made this decision because they wanted to impose a higher statewide minimum than defined in the other codes. More information on CALGreen can be found in the Case Study later in the text. In 2002, the European Parliament approved the Energy Performance of Buildings Directive (EPBD), which required member nations to develop methods to calculate the energy performance of buildings, to establish minimum energy performance requirements for both new buildings and existing large buildings subject to major renovation, and to develop energy performance certification programs. An energy performance certificate (EPC) must be issued when any building (commercial or residential) is constructed, sold, or rented to a new tenant. In 2010, the EPBD was revised (“recast”) to direct that new governmental buildings would be built to nearly net zero energy criteria starting December 31, 2018, and for all buildings starting December 31, 2020. The definition of nearly net zero is to be established by each of the European member states as reflective of their local climate and economic conditions (e.g., local cost of energy). Because of the wide variation in economic, social, political, and technological conditions between the various countries and jurisdictions of the world, it is not surprising that there needs to be a wide variety of approaches taken if we want to truly achieve moving high-performance building design into the mainstream.

Case Study CALGreen—America’s First Statewide Green Building Code CALGreen was developed in 2010 to promote the design of efficient and environmentally responsible residential and nonresidential buildings in California. The CALGreen code is part of the overall California Building Standards Code and is the first statewide green code established in the United States. It was developed, in part, in an effort to meet the provisions of Assembly Bill (AB) 32, which requires a cap on greenhouse gas emissions by 2020, with mandatory reporting. The initial CALGreen Code became effective January 1, 2011, and has been regularly updated and modified since then. The most recent versions are available online (State of California 2018). Some similarities to other certification or rating systems such as the LEED programs include standards for stormwater pollution prevention, light pollution reduction, indoor and site water savings, construction waste management, energy performance, outdoor air delivery, carbon monoxide monitoring, and materials selection. In some cases, CALGreen has stricter targets than LEED; in others, LEED is stricter. And, in many others, the requirements are identical. There are several CALGreen requirements not found in LEED, such as installing water meters on buildings with areas greater than 50,000 ft2 (4600 m2), providing weather-resistant exterior walls and foundation envelopes, defining the type of fireplaces that can be installed, and employing acoustical control (interior and exterior). In addition to the mandatory statewide CALGreen requirements, a city or county may adopt local ordinances to require more restrictive standards that go above and beyond the mandatory measures. These packages of voluntary measures, called Tier 1 and Tier 2, include a set of provisions from each code division. These provisions are

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additional measures which are stricter than the mandatory codes. For instance, building energy performance must exceed the California Energy Code (Title 24) by 15% and 30% for Tier 1 and Tier 2, respectively. The full text of this code is viewable on the ICC website (ICC 2016).

3.4

BUILDING CERTIFICATION, RATING, AND LABELING SYSTEMS 

There are alternative programs that help guide and define a high-performance building beside the codes and standards described in the previous section. In fact, before the development of IgCC/189.1, certification systems such as LEED in the United States, the Building Research Establishment Environmental Assessment Method (BREEAM) developed for the United Kingdom, and the Green Globes program were in place. These tools incorporate a coordinated method for accomplishing, validating, and benchmarking sustainably designed projects. As with any generalized method, each has its own limitations and may not apply directly to every project’s regional, political, and owner design-intent-specific requirements. But, first, we must define the key differences between each of these. Certification Systems. Certification programs such as LEED, BREEAM, or Green Globes are designed to certify that a building meets standards as defined by each program for a high-performance building. Some have multiple levels of certification, depending on how many of the qualifying criteria are met. There are a wide variety of certification programs available around the world to measure the environmental impact and performance of buildings. Some of these programs focus on the projected design performance based on results of computer modeling and simulation while others are limited to building performance based on actual collected data. Besides what data are used to qualify a building for these programs, the other distinguishing factor is whether they are narrowly focused on energy (and/or water in some cases) use, or are more broadly focused to also encompass other sustainability categories and IEQ. It could easily be said that the high-performance building movement really started in earnest with the initial establishment of BREEAM in 1990. BREEAM is a creation of the Building Research Establishment (BRE) in the United Kingdom and began as a voluntary, consensus-based, market-oriented assessment program. Originally, BREEAM encouraged and benchmarked only office buildings, although it has now been expanded to apply to most building types. The program has evolved to include both new and existing buildings, as well applications for most building types. The program transitioned in 2011 from being optional to being mandatory on all new construction as well as implemented postconstruction review requirements in the United Kingdom. Several other countries and regions have adopted BREEAM or have developed/are developing related spinoffs. Examples of other building certification programs throughout the world include Australia’s Green Star and National Australian Built Environment Rating System (NABERS), Japan’s Comprehensive Assessment System for Built Environment Efficiency (CASBEE), Hong Kong’s Building Environmental Assessment Method (BEAM), and the Estidama program in the United Arab Emirates (BRE 2019). The method primarily used in the United States is the LEED program, created by USGBC (2019a). This organization started offering this system in the late 1990s and was intended to be a voluntary, consensusbased, market-driven green building certification system. LEED evaluates environmental performance from a whole-building perspective over a building’s life cycle, providing a numerical standard for what constitutes a green building. Projects wishing to obtain LEED certification will track and document how well the building meets a set of criteria specified in various LEED credits, with a varying number of points

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for meeting each credit. A minimum number of points (currently 40) allows the building to be LEED certified. Higher levels of recognition are given for a greater number of points (rated Silver, Gold, or Platinum). The USGBC’s goal is to raise awareness of the benefits of high-performance building, and it has transformed the marketplace. The introduction and acceptance of the LEED program was key to high-performance buildings rapidly entering designers’ and owners’ consciousness in the 1990s and early 2000s. Several cities in the United States now require LEED certification for building projects above a certain size or classification (such as a government building); thus, LEED is (in these cases) becoming a de facto highperformance building code. Rating or Labeling Systems. A rating is a method of comparison based on performance. An example of this is the overall energy use intensity (EUI) compared to a standard level of performance for that type and size of building in that particular climate. These programs give a relative ranking of how this building stacks up against its peers. In comparing buildings, there must be some common metric for comparison. For example, in vehicles this would be in terms of miles per gallon or kilometers per liter of fuel (or equivalent if an electric vehicle). In buildings, this metric is in terms of total energy consumption per unit floor area (usually using the total conditioned floor space, which ignores unconditioned areas such as mechanical rooms, parking decks, and so on.). The units used are expressed as thousands of Btus per square foot per year (kBtu/ft2·y) or kilowatt-hours per square meter (kWh/m2·y). There are a number of examples of building rating or labeling systems that have been developed and applied in various circumstances. Most commonly, the performance metric evaluated is the energy consumption. One significant example is the building ENERGY STAR® program operated by the U.S. Environmental Protection Agency (EPA). This program is similar to the ENERGY STAR ratings label given to higher-efficiency products such as household appliances. Another metric of energy performance is the Building Energy Quotient (Building EQ). The program provides a method to rate a building’s energy performance both as designed (asset rating) and as operated (operational rating). Assessment of building performance is done at both the as designed and the as operated levels so owners can compare the actual performance of the building to its potential performance. The assessment process is also structured to provide information on methods or measures that could help improve overall building energy performance. The building owner also receives a report with recommendations for how to reduce energy and water use while maintaining acceptable IEQ. More details on building benchmarking of performance through rating or building labeling systems are given in Chapter 13.

 Summary Building certifications and ratings can play an important role in improving design and operation, but the ultimate design will always be specific to each building and its owner’s objectives. Excellent building design and operation can occur without a certification or rating. Recognizing this, many building owners are choosing to invest time and money into having their facilities rated and certified for reasons beyond building performance. Many owners justify this investment based on the image the certification portrays. For some this image is important for marketing by showing alignment with company values and displaying a commitment to bettering the environment. In some cases, it is also an opportunity for competitive advantage—attracting top employees and customers, as well as positioning themselves to be able to demand higher lease rates or a higher building value at resale. Certifications are important to the design industry in that they provide a foundation from which designers and owners can discuss the expected level of performance of the building. These certification programs have significantly changed the industry; owners initiate the conversation about their desire to have a high-performing building and, in many cases, they do so by referencing the need to have a certificated building. It is the responsibility of the design team to further

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explore the actual needs and expectations of the owner and to guide them as to the best design direction with the budget in mind, which may or may not result in certification. Ratings also play an important role, but their focus is on an existing building’s performance. A rating compares a building’s performance to other buildings that are similar in function and within the same climate. This comparison can be conducted on a relatively new building (say within 12 to 18 months of operation) or one of significant age. The rating of a new building is powerful because it can gage how well the building is performing relative to what was anticipated in the design. Older buildings often implement the rating process to identify if there is opportunity for improvement. As one can see, there are different reasons for and strengths to certification and rating systems. Therefore, their implementation is dependent on the building and the owner’s objectives. The procedures used by those organizations and governmental agencies providing building rating systems vary. Many building rating programs use static building labels. In other words, the building’s energy (or other high-performance attributes) is evaluated once, the label is applied with an assessment date, and the providing organization does no reassessment to determine if the building continues to actually meet the original specifications. The application of dynamic labeling is preferred. A few of the building rating programs do include a reassessment (e.g., every two years) and buildings not continuing to perform to the standards set may lose their building label (Means and Walters 2010).

3.5

GUIDELINES 

A guideline is a set of design criteria or goals that an outside entity has decided a project should look to incorporate. A number of professional organizations (such as ASHRAE or CIBSE), trade associations (such as the Sheet Metal and Air Conditioning Contractors National Association [SMACNA]), and other entities produce guidelines related to their field of expertise. In the case of high-performance or energy guidelines, the guidelines identify methods for minimizing the overall environmental footprint or energy consumption of a project. Examples here include the Advanced Energy Design Guides (AEDGs) that ASHRAE, the American Institute of Architects (AIA), the Illumination Engineering Society (IES), and the USGBC have produced with the backing of the U.S. Department of Energy (DOE). The AEDGs provide guidance for a project team on ways for their design to achieve a certain percentage level of energy performance better than Standard 90.1, specifically for a given building type and climate zone. Guides that have been produced for the 30% and 50% improvement levels are in development for (net) zero energy buildings (with the first one for K–12 schools already published as of this writing). Zero energy (or net zero energy) buildings are those that generate as much energy on-site as they will consume during the course of a year. Another high-performance-related document is the Indoor Air Quality Guide. The summary document is available for free while the detailed document is available for purchase. This guide was released in January 2010 and was developed in conjunction with AIA, the Building Owners and Managers Association (BOMA), SMACNA, the EPA, and USGBC. This document is designed for architects, design engineers, contractors, commissioning agents, and all other professionals concerned with indoor air quality (IAQ).

3.6 COMPARATIVE SUMMARY OF THE PROGRAM DIFFERENCES  A quick review and summary of the key distinctions between the various types of programs related to high-performance buildings is as follows:

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Standards and Codes. These are the most rigorous of the program types. Standards are documents that set minimum criteria for a specific aspect of a building (such as energy efficiency or IAQ), or in the case of a standard such as IgCC/189.1, which defines a high-performance building from a holistic perspective. Standards are generally written using language such that if they are adopted or referenced as part of a local jurisdiction building, they can be legally enforceable. Certification Systems. These are designed to evaluate the building design and other associated factors with respect to a number of criteria that can be used to define a high-performance building. The building project much meet a minimum number of these criteria to be able to achieve the certification. A few of the examples given are the LEED, BREEAM, and Green Star programs. Rating Systems. These programs compare the performance of a building to a given standard level or to similar buildings in the same climate zone. These most often are oriented toward the evaluation of energy consumption. Guidelines. A guideline is a collection of recommendation or suggestions that provide guidance toward the design of a better performing building.

•

•

•

•

More details on how the various programs cover the various topical areas are included in subsequent chapters. In addition, various case studies are included through this book that will highlight examples of high-performance building applications or criteria.

Additional Resources for Further Study Several additional study and reference documents are available www.ashrae.org/HPBSimplified. For this chapter, this includes the following: •

at

An overview comparison of the LEED program and IgCC/189.1 File name “Overview of High-Performance (Green) Building Certification Systems and Standards”

Application for a Future Career In most chapters of this book, we provide suggestions on ways that a beginning professional can achieve their goal of getting involved in the area of highperformance buildings. If this chapter taught you anything, part of that should be the realization that there are a lot of various technical, legal, social, and other aspects that all play a part in developing high-performance buildings. In this portion, we cover just a few of the ways that you can prepare yourself to enter this field. The first is professional licensure. For an engineer, the first step is obtaining Engineer in Training (EIT) designation. The procedures for doing so vary state by state in the United States, but all require passing the Fundamentals of Engineering exam (FE exam). Some engineering programs require taking this exam as requirement for graduation, but even if yours does not, it is recommended to take it (and pass!) anyway. It is much easier to take and pass the exam while all that engineering knowledge is fresh in your mind. After a period of working as an engineer in industry, you will be able to apply for the Professional Engineer (PE) designation. This requires you to take

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another exam, this one focusing more on the application of engineering concepts to real-world problems. Depending on the state or situation, you may be required to select a specific discipline in engineering, for example mechanical or civil/structural. An alternative for people interested in high-performance buildings is to get registration as an architectural engineer. The exam for this particular engineering license is a broad mix of general mechanical, electrical, plumbing, and other topical knowledge that a professional in the buildings industry would be expected to know. Other disciplines related to high-performance building have their own licensure or certification programs—for example, landscape architecture, where most U.S. states require licensure to practice. Another way to establish qualifications in high-performance buildings is to obtain credentialing in the LEED program through the USGBC. The first step in this would be as a LEED Green Associate, which signifies core competency in the topic. To earn this, you must pass an exam on the LEED programs. Later, you may wish to move up to a LEED Accredited Professional with a specialty in one of the LEED programs (such as building design and construction or operations and maintenance [O&M]). More information on these credentials can be found in Chapter 17. Other certification programs related to high-performance buildings are offered by organizations such as ASHRAE. ASHRAE offers certification (after passing the related exam) in several areas related to high-performance buildings, including the following: • • • •

Building Energy Assessment Professional (BEAP) Building Energy Modeling Professional (BEMP) High-Performance Building Design Professional (HBDP) Building Commissioning Professional (BCxP)

Other organizations, such as the Association of Energy Engineers (AEE), offer certification programs as well. Obtaining licensing, accreditation, or credentialing is not the end of the process. One thing you will quickly realize is that to stay active in the field you must adopt a commitment to lifelong learning. Most of the licensing and many of the credentialing programs require some sort of formal continuing education to maintain the license or credentials. This will force you to keep your skills up to date, but you should realize that this is important regardless. Take advantage of opportunities that might be available through professional societies and organizations. These organizations provide opportunities to continue your professional growth, as well as making new friends and associates along the way.

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Discussion Topics, Exercises, Investigation Study Topics, and Assignments For Class Discussion: 1. 2. 3.

Why were high-performance (or green) certification programs, rating systems, codes, and standards created in the first place? Think about what you consider to be the top five items or issues that should be included in any high-performance building certification/rating system. What items should be considered but be optional? Assuming high-performance buildings may become mandatory (i.e., code) in the future, what types of requirements should be required versus what ones should be optional? Note that this is different from the previous question in that this involves mandatory requirements that all buildings would need to follow. In-Class Exercises:

1.

Imagine yourself as being part of the city council or group of governmental officials that determine the building codes for the locality where your college or university is. Think of the following issues and then be prepared to make a case for or against the adoption of a high-performance building ordinance for this city. a. In the context of local politics and opinions, do you think there would there be support for such an ordinance? b. Considering the five major topical areas in most high-performance building program (site, water, energy, IEQ, and materials), rank these in order of importance that this community would support for inclusion in such an ordinance. c. Would you apply this code for only a specific set of buildings? (For example, every building above a certain floor area.) If so, what restrictive criteria would you propose?

Next, select a partner and explain to them your proposed position and work together to develop a joint proposal that you both can agree on.

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2.

Individually, imagine you are involved with creating a new high-performance building certification program. Think how you would allocate the total points for this certification program among the following key topical areas: a. Where the building site is to be located and connection to the rest of the community b. The building site c. Water efficiency d. Energy efficiency e. IEQ (air quality, acoustics, lighting, thermal comfort, and so on.) f. Materials use g. Construction practices h. Operation and maintenance Are there any areas that you think might be missing from this list? Next, as a class compile your list of point allocations and collectively come up with a consensus. For Further Investigation and Study:

1. 2. 3.

Investigate and summarize the historical development and implementation of the voluntary high-performance building programs in the United States (for example, LEED). Investigate the development and adoption of mandatory high-performance or green building codes in localities in the United States. Investigate and summarize the historical development of high-performance or green building programs in the following locations: a. b. c. d. e.

6.

7. 8.

Europe and the United Kingdom India Australia Asia Middle East (e.g., Kuwait, the United Arab Emirates)

Some states in the United States have recently adopted laws that forbid state entities from pursuing LEED certification. Identify these and investigate why this has happened and the viewpoints from all sides to this politicized issue. Provide your opinion on how this impasse might be resolved. Investigate the IgCC/189.1 in more detail. If you were part of your local building authority and asked to help adapt IgCC/189.1 for your community, are there any requirements you would propose to be struck from inclusion? Investigate the current status of building codes in the community you live in. Are there energy or other high-performance-building-related codes that are officially part of the locality’s building permitting process? How strongly are these enforced?

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Section 2: Design CHAPTERS  • Chapter 4—Building Design and Delivery Process • Chapter 5—The Commissioning Process • Chapter 6—Sustainable Sites: Locating the Project • Chapter 7—Water Efficiency and Utilization • Chapter 8—Energy: Conversion, Distribution, and Utilization • Chapter 9—Energy: Sources and Generation • Chapter 10—Indoor Environmental Quality (IEQ) KEY IDEAS  • Key issues, technologies, and methods in designing a high-performance building, including: • Design and delivery process • Commissioning • Site, water, energy, IEQ, and materials considerations

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4

Building Design and Delivery Process Reflection Exercise: Who Influences and Makes Decisions Related to a Building’s Design and Construction? Spend the next few minutes creating a list of all the parties or individuals that play a role or take part in a building’s design and construction. Looking at this list, identify which of these individuals are involved in building design, which are involved in construction, and who is involved somewhere outside the design or construction process. What would the different relationships between these various parties look like? Note: there may be some parties or individuals that you come up with that fit in multiple categories—these should be identified as such. Form into small groups and compare your lists. Take some time to consolidate your individual lists into one master list. The built environment is essential for the quality of life we have come to expect. On average, individuals spend more time inside buildings each day than they do outside. Therefore, it is critical that buildings provide all the items needed for the occupants to be productive, safe, and comfortable. Buildings are designed and constructed to meet the needs of the occupants, but it is clear that there are many different functions that take place indoors and influence the buildings composing our built environment. This chapter introduces the criteria considered in the design, the stakeholders that influence the decisions along the way, and the different processes used in the construction of a building.

4.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: • • •

•

Authority having jurisdiction (AHJ) Design team Phases of design • Schematic design • Design development • Construction documents Project delivery methods 37

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• • • •

4.2

Design-bid-build Design-build Construction management at risk Integrated design

BUILDING TYPE CLASSIFICATION 

Before diving into a discussion on design and construction, it makes sense to first consider the different types of buildings. The broadest classification of a building is whether it is new or existing. Construction of new buildings with high performance as a goal is obvious, but only a very small fraction of new building square footage is added annually (see Figures 4.1 and 4.2 below). Existing buildings provide the greatest opportunity to affect energy consumption as they were not built to the higher efficiency standards that are used today. The next level of classification is in the type of building occupancy, primarily defined as commercial, industrial, or residential. There are some buildings that are deemed mixed occupancy, meaning that the building includes more than one occupant type. Examples of mixed occupancy can be a manufacturing plant (industrial) with portions dedicated to offices (commercial), or a building that contains retail space on the lower level(s) and residential space in its upper floors. For the purposes of this book (and to be consistent with existing building codes and standards), residential is assumed to include single-family home applications or apartments less than three stories in height. All other buildings where people live (for example, high-rise apartments or dormitories) are classified as commercial buildings because they are often constructed differently than and can apply techniques that are otherwise cost prohibitive or unreasonable to smaller residential applications. Commercial buildings can be further broken down in classification by use or function. There are many different types, such as schools, offices, hospitals, laboratories, hotel, retail, and so on. The use classification of a building is important especially when thinking about its performance and design because the different uses result in more or less resource consumption. For example, an office building has moderate energy use as a result of equipment, lighting, and heating/cooling but its water use is generally quite low. However, a hospital requires substantially more energy for additional equipment and higher light levels, and water use will also be much greater as a result of increased bathroom, cooking, laboratory, and laundry needs. Similarly, a restaurant will have a high energy and water usage for the cooking and cleaning processes involved. Office buildings are not better than hospitals or restaurants because they consume less energy, they are simply different in what they need to function to meet occupants’ needs. This example illustrates that high consumption buildings cannot be eliminated (imagine if we did not have hospitals or restaurants), but it is rather essential that they be designed to consume as little as possible and eliminate waste.

4.3

DESIGN CRITERIA 

Each of the building classifications mentioned previously have different needs and high-performance opportunities based on their age (new or existing), occupancy, and function. As a result, they also have different design criteria. Most buildings have some common considerations, such as occupant health and safety, minimizing environmental impact (carbon footprint, water use, energy consumption, use of recycled materials), indoor environmental quality (IEQ) (lighting levels, daylight, air quality, thermal comfort, acoustics), budget, timeline/schedule, maintenance and operation complexity, and so on. However, each project is unique and will prioritize these criteria differently. Many things influence the design criteria for a specific project, including the owner, the design and construction team, and society at large. The design and construction teams can provide input and

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Figure 4.1. Distribution of building size for U.S. commercial building stock. (EIA 2015)

Figure 4.2. Distribution of ages for U.S. commercial building stock. (EIA 2015)

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suggestions, but it is ultimately the owner who has the most influence. The owner plays a critical role in determining the priority of specific items in a building design because they also provide the money or financing for construction. An owner who builds a facility for their own long-term use and occupancy is likely to make different decisions than an owner who is leasing or developing a building for sale. This may result in decisions that do not optimize performance if there is a high first cost impact; an owner who intends to stay in the space for many years will consider utility and maintenance costs as well as employee productivity as much higher priorities, even if it means the first costs are higher, because there is the opportunity to recover this initial investment over time. If the space is being leased, the leasing agreement structure and the market in the area can be influential. Leasing agreements that require the occupant to pay utility expenses do not incentivize the owner to select design options that reduce energy or water use unless the market in that location shows higher lease rates and resale value for buildings that claim to be high performance. Besides the economics related to the operation of a building, an owner that occupies the building may also choose to prioritize the building IEQ to best protect their No. 1 investment—their employees. As indicated in Figure 4.3, an investment during construction to improve employee productivity is minor when put into perspective of overall business expenses over the life of a building. As explained previously, the market for resale, space lease, employees, and customer connection can certainly drive decisions. These are direct influences. An indirect influence is legislation supported and passed in different jurisdictions that determine building design and construction requirements, usually in the form of codes and standards. The public continues to indirectly support this through the allocation of tax dollars at the jurisdictional level to fund the employment of code officials, also referred to as the authority having jurisdiction (AHJ). As described earlier in this book, the AHJ is responsible for the adopted code enforcement, which includes reviewing design plans and inspecting for construction conformance.

Figure 4.3. Distribution of facility operating costs through a typical facility life. (Data from Romm 1994)

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4.4

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THE DELIVERY METHOD 

The process used from the beginning of project design to completion of construction is referred to as the delivery method. The method selected is influential because it ultimately has legal contractual obligations defined for each of the parties involved. There are four primary delivery methods used: • • • •

Design-bid-build Design-build Construction management at risk Integrated project delivery

These methods will be explained later, but it is important to first understand the roles of individuals involved and the different stages of the design and construction process.

 Design Team The design team is traditionally made up of architects and engineers (Figure 4.4). The purpose of the design team is to develop documents that represent the owner’s needs and expectations for construction. It is common on a complex project for the architects to include specialists such as interior architects, interior designers, landscape architects, acousticians, building envelope consultants, sustainability specialists, and others. An architect works with an owner to define the building programming needs—how many rooms, room sizes and adjacencies, space flow—and prepares the building design to accommodate these needs while considering the prioritized criteria previously introduced. In addition to considering the function of the layout, the architect also focuses on issues of life safety (e.g., exit paths from the building), aesthetics, and material selection and assembly (e.g., number, type, and location of windows). The engineers usually consist of practitioners from multiple disciplines (e.g., civil [site], structural, mechanical [plumbing and HVAC], electrical [power and lighting]) and often from more than one design firm. For a list of the many different potential participants and more detail related to their roles in the design process, reference the list of Design Disciplines from the Whole Building Design Guide (NIBS 2019). The engineers generally focus most of their time on making the concepts developed by the architects work. Items within their purview include, but are not limited to, confirming the building is structurally sound, managing rain water on the property, providing heating and cooling, ensuring the light levels are sufficient, and providing electricity to all the equipment requiring power. Much of the work of an engineer goes unnoticed, even though it is essential for building function, because it is often hidden above a ceiling, behind walls, or located in rooms removed from the public view. The engineer also plays a critical role in maintaining occupant health and safety, as well as providing an environment that enhances productivity. Figure 4.4. The traditional buildBoth the architects and the engineering team play an essential role; neither are more important ing design team. than the other in the design process. They both

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bring different expertise to the process and have the common goal of satisfying the client by meeting the owner-defined criteria as well as the minimums established for occupancy dictated by code. The design of a high-performance building must also factor in the needs and perspectives of those that will operate and maintain the building. Even though these are not generally included in the design process, they will ultimately determine the overall efficiency of the building operation. Thus, in this text we refer to the design team, a term that includes all parties that determine the ultimate level of building performance.

 Phases of Design The design team works closely to develop a set of documents to be used for construction that meet the owner’s priorities. There are three primary steps to get from a building concept (when the owner states they would like to build a new or renovate an existing building) to being ready for construction. These three phases are as follows (Figure 4.5): •

Schematic design. The schematic design phase typically consists of defining the scope of the project, creating the program of needs and space use, and creating preliminary sketches to aide in communication with the owner. This phase’s purpose is to set the direction for the project. This is also when the design criteria are set and specific priorities are defined for a successful project. Setting priorities and effectively communicating these to the design team is critical before moving to the next phase of design, as many items are either much more expensive or impossible to be added once other design decisions are made. For example, a building with high performance as a priority can be designed so the window type, position, and orientation can partially offset the lighting needs within the space, but this needs to be planned and accounted for up front to optimize the systems’ interaction. • Design development. Once everyone is comfortable with the project direction, the design development phase begins. During this phase the concepts introduced during schematic design are advanced. The exploration of methods of optimizing economics and performance as well as addressing constructability issues are conducted at this time and require extensive coordination between the different disciplines. Building plans, construction documents, and details are started during this phase. These documents are not so complete that construction can begin, but they provide enough information that preliminary pricing is possible. • Construction documents. The final phase of the process is the construction document phase. The construction documents consist of drawings, technical specifications, and (increasingly) computer models. The design team is responsible for coordinating and communicating all the details related to construction, from the most obvious large components (e.g., connection methods) to the minute details (e.g., the size and number of fasteners). These documents are used by the contractor during construction are needed to show codecompliance before construction permits can be issued. They are also used as the basis for pricing and become the foundation of Figure 4.5. Phases of a legally binding contract with the construction team. building design.

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 Construction The construction team is commonly led by a general contractor. The general contractor may do all the work on a small project, but it is more likely that a team of individuals is needed because of the many specialty areas involved. Other contractors (typically referred to as subcontractors) may specialize in mechanical, steel, concrete, electrical, fire alarms, and so on. The general contractor’s time and attention is devoted to coordinating subcontractors, scheduling, logistical planning, and interacting with the owner and design team (especially when changes are made). There are two phases to construction: bidding/negotiation and construction administration. Bidding and negotiation is the process in which the contractor develops a price to complete the proposed building based on the construction documents. The owner then selects the contractor with whom they want to work, negotiates a final price, and enters into a legally binding contract that says the contractor will do the work identified in the construction documents within a defined timeline and that the owner agrees to pay the contractor for this service. Once the contract is signed, the construction administration phase begins, described further in Chapter 12.

 Project Delivery Methods Having a basic knowledge of the parties involved as well as the phases of the construction process enables discussion of construction delivery methods. There are four dominant delivery methods, all of which are acceptable, with advantages and disadvantages. Therefore the most appropriate method depends on the application. •

•

Design-bid-build. The most traditional, and for many years the only, delivery method is design-bidbuild. In this method, the architect is hired by the owner to complete the building design and then hires the remainder of the design team. Once the design is complete, the construction documents are released for bid. The architect serves as an advisor for the selection of the contractor, and the owner then has a separate contract with the contractor. This project delivery arrangement is illustrated in Figure 4.6a. Because this is the traditional method used for construction, it is familiar, meaning that the roles of the professionals and the owner are well defined. The primary advantage to this method, besides familiarity, is the competitiveness of the bids between contractors that can result in a lower price. The disadvantages include the need to have the design complete before beginning construction, potentially slowing down the process; the price not being determined until design is complete and potentially requiring reworking the design if price comes in high; and the architect and contractor not being contractually connected, with the owner serving as the go-between and resolving disputes. This delivery method is best for projects that are unlikely to change during construction and do not have a restrictive time schedule. Design-build. Design-build differs from design-bid-build in that the owner firsts establishes a single contract for both design and construction with the construction contractor rather than the architect. The contractor then either hires the design team or uses an in-house design team. This contractual arrangement is shown in Figure 4.6b. The most significant advantage of this method is having the contractor acting as the project lead, giving the opportunity to lock in pricing much earlier. This reduces the risk for an owner because do not wait until the design is complete before knowing the construction costs. Although the owner knows the budget sooner, the owner may not receive the lowest price possible; this cannot be confirmed as it is not always a competitive bid process. However, this method reduces conflict because all aspects of construction work through a single party. The fact that the owner is less involved and there is only a single responsible party is also a disadvantage

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(a)

(b)

Figure 4.6. Relationships of the various parties in traditional building processes: (a) design-bid-build, (b) design-build.

•

•

because there are no checks and balances to ensure quality control. This can be a concern given the contractor has incentive to complete the project faster for less money. This is an especially good delivery method for simple projects that are especially time sensitive, since construction can commence while design details are still being refined. Construction management at risk. Construction management at risk is a recently introduced delivery method that addresses some of the disadvantages of the previously defined methods. In this method the owner hires both a contractor and architect during the design phase. The contractor during the design phase is simply acting as a specialized consultant, helping the design team with budgetary information as well as providing guidance on constructability and timeline. Once the design is complete, the owner then puts the construction documents out for competitive bid. This allows for more competitive pricing as well as builds in the safeguard of checks and balances seen in design-bid-build. The owner then enters into another contract for construction that may or may not be with the same contractor that participated during the design phase. This arrangement is depicted in the Figure 4-7a. The dashed line between the contractor and the architect is to signify the fact there is interaction but no formal contract between these parties. This is a very popular delivery method today, surpassing design-bid-build in terms of number of projects and requiring more owner involvement than design-build. Depending on the owner and the project, this can be identified as an advantage or a disadvantage. Construction management at risk is often the preferred delivery method for projects that are more difficult because of technical complexity or required multitrade coordination. Integrated project delivery. The last of the delivery methods is integrated project delivery. This is the newest method for the construction market and is currently the least used. However, it is looked at as being more popular in the future, especially for projects focused on high performance. The roles of those involved are defined in this method to facilitate a team approach. The owner is considered an integral part of both the design and construction, as are the design team and the contractor. There is contractually shared responsibility, liability, and risk for the project success and everyone is equally accountable. This method is shown in Figure 4-7b. All participants are incentivized to make the project successful, as there is shared risk and reward. This means if the project is completed faster and less expensive than initially

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(a)

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(b)

Figure 4.7. Relationships of the various parties in newer and/or more complicated building processes: (a) construction management at risk, (b) integrated project delivery.

defined, the money saved is distributed to all the parties—the owner saves money and the design team and contractor(s) see a greater profit. For example, if the overall cost for the project completion is $30,000 less than the original budget, the owner saves $10,000, $10,000 goes to the contractor(s), and $10,000 goes to the design team. This incentivizes all parties to target this outcome. It is not always evenly split between parties, depending on the contract terms at the beginning of the project. In a similar spirit, if the project is $30,000 over budget, everyone pays to cover this cost, which encourages all parties to work to avoid this outcome. This method allows for a much more collaborative and thorough design at the beginning of the project with all the professionals involved, thus resulting in the elimination of expensive changes once construction has begun. This is seen as the best method because it eliminates the conflict and animosity between parties and encourages the focus to be on the best design possible. It has been shown that this method of delivery is most likely to have a building completed on time and within budget because of its efficiency and team approach. However, there are disadvantages to this method that prevent it from being the standard delivery method used today. The disadvantages include it being unfamiliar, it requires a very involved and knowledgeable owner, and issues related to financing, insurance, and contracts. This method is most frequently applied to complex projects with an owner (or a representative) that wants to be very engaged and has their own funding to eliminate the need for financing. Because of the collaborative relationships involved with this delivery method, a bidding process is not used. Rather, the design team and contractor are selected by the owner, often using an interview process. The construction documents are created in a collaborative environment based around the owner’s priorities, needs, and budget. This delivery method often takes far more time and incurs much higher expenses during the design phase of the project compared to other delivery methods, but this time and money are offset because there are little to no change orders at the end of the project. This is a result of a more thorough coordination early in the project planning. Cost savings are attained through the reduction or elimination of change orders during construction and incentivizing coordination/integration. Thus, this delivery method can result in a lower overall project cost compared to other delivery methods.

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4.5

SUMMARY 

There is not one perfect delivery method for any project, but rather each project must consider the prioritized design criteria defined for its success, the capacity and experience of the parties involved, and the complexity, budget, and timeline for the project. What is clear, as buildings become more sophisticated and there is higher priority set on performance, is that doing things in a more collaborative manner is essential. This means that the construction industry will be required to evolve and entertain new practices and methods to accomplish these goals.

Application for a Future Career There are various and significant opportunities for professionals in the design and construction industry. Depending on their interests, one may find a position working as a part of the design or construction team or being the business owner contracting the building. The design and construction teams and the many related consultants and subcontractors are defined earlier and provide distinct opportunities, focus, and knowledge. An owner can be the individual that owns the entity initiating the project, but it is more common that the owner is not the CEO or president of the company. Rather, the “owner” is usually a representative of the owner. Considering most company presidents or CEOs need to dedicate their time and attention to the daily function of their business, it makes sense they cannot afford to also engage heavily in the construction process. For this reason, as well as the fact most owners do not have interest or expertise in construction, they either have someone within their staff or hire someone to serve in the capacity of owner’s representative for the duration of the project. There is no shortage of opportunity or variety when considering where one might fit within the building design and construction industry.

Discussion Topics, Exercises, Investigation Study Topics, and Assignments For Class Discussion: 1.

2.

There is often tension between architects, engineers, and contractors, even though they are all working toward the common goal of providing an owner with a building that meets their defined criteria. Discuss items that may contribute to this tension and who is most likely at fault. Are there delivery methods or specific projects that result in greater potential for conflict? Are there things that can be done to limit or minimize the degree of frustration experienced? Which building project delivery method do you think is the least suited for producing a high-performing building? Which is the best suited, or at least more likely to result in high performance?

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In-Class Exercises: 1.

Given the following three new buildings create a list of design criteria that should be accounted for each project. What are the similarities and differences of criteria between the lists? Next, looking at these lists prioritize the most important three criteria for each project and justify the reason these were selected. • • •

2.

College campus office and classroom building Hospital Fast food restaurant

Considering the three buildings given above, which delivery method is most appropriate for each? Explain your selection. For Further Investigation and Study:

1.

Select a delivery method and find a building that has been executed using this method. Create a fact sheet defining the following information for this building, including: • • • •

2. 3. 4.

Building type and function Building location Building owner Specific attributes of the building that affected building design or construction

Explain why the delivery method selected for this building was a good choice or why a different delivery method would have been more appropriate. Research the evolution of the role of specialty consultants in building design and construction. Select a specific specialty and clearly explain in what circumstances their expense can be justified as part of a project’s budget. Explore contractual issues between architects, engineers, contractors, and owners. Legal issues and litigation are important, especially on projects that have a high profile and budgets that reach millions of dollars. Inquire with local architects, engineers, or city planners/code officials if any controversial building projects were involved in the local area. What were the issues involved? How were they resolved before (or if) the building project was eventually approved and built?

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5 The Commissioning Process 5.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: • • • •

Basis of design (BoD) Commissioning provider (CxP) Testing and balancing (TAB) Owner’s project requirements (OPR)

• • • •

Reflection Exercise: What is Commissioning? The concept and term commissioning first referred to the process whereby a new naval vessel (or one that had undergone significant repair and renovation) is first brought out on an initial short voyage to check the operation of all systems. Another term for this is “taking the ship out on its sea trials.” During these sea trials, all systems and equipment are checked to verify they meet the design requirements and specifications; obviously you would not want a major malfunction to occur out in the middle of the open ocean. Only after the ship passes its sea trials would it then be commissioned, or formally brought into service. Any issues found during the sea trials must to be fixed and rechecked before the vessel is commissioned. Based upon your experience, think of a situation or circumstance where the design of a system, component, product, or process did not appear to be well thought out or was somehow out of control. • •

•

Identify the situation or circumstance Summarize the overall basic problem from each of the main stakeholders’ perspectives • How could or should each of these be addressed? • Are any of these not beneficial to a solution but rather just more convenient for others? Is there anything from the situation that you would have changed in the design or the process that would have benefited all parties?

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Consider an example with a building that tends to be overcooled during the summer time. Surveys and studies indicate this to be a fairly common scenario, at least in the United States. The possible reasons for this are varied. For example, the HVAC controls may be not setup properly. Or, overcooling could be done on purpose to prevent the building operations team from getting complaints of the building being too warm (but not considering the potential for going too far and producing conditions that many feel to be too cool or cold). This is the type of situation that commissioning can help avoid. Commissioning is a quality-focused process that enhances the delivery of a building project by providing continuous oversight; it lasts from the predesign phase throughout occupancy and is administered by a commissioning provider (CxP). How, and to what extent, an owner incorporates commissioning into their project depends on the owner’s understanding of the process and its expected results. Factors that determine if and the extent of how commissioning is incorporated in any given project include the following: • • • • •

5.2

How long the owner intends to hold the property The owner’s staff capabilities Funding mechanisms for design, construction, and operation The project schedule Ownership experience

COMMISSIONING: CONCEPT AND ADOPTION 

Commissioning establishes benchmarks for evaluating the building’s ability to achieve the owner’s defined goals and objectives. It is applied to new building projects and existing facilities to ensure that a facility meets the needs of the occupants and effectively and efficiently deliver the owner’s purpose for that building and their organization’s financial goals. Commissioning therefore provides benefits to everyone: the owner, the designers, construction team, building occupants, and building operators. It helps to reduce risk and with fewer change orders, ultimately improves system efficiency and operation. The true measure of a high-performance building is how it performs over its lifetime, and proper commissioning of a building helps ensure that intent. Commissioning is growing in importance in the industry and is now being incorporated into building codes. One contributor to this trend is the mandatory requirement for commissioning in building certification programs and standards; another is a growing awareness of the benefits commissioning brings to a project. There is some debate currently on whether all high-performance buildings (or even all buildings) should be required to undergo a full commissioning process. Certainly any building that includes complex systems or a larger number of energy and water consuming devices should be considered for a least some level of commissioning. Related to this, the minimal energy codes (ANSI/ASHRAE/IES Standard 90.1 and the International Energy Conservation Code [IECC] in the United States) require commissioning of HVAC controls. The commissioning process should begin early in the predesign phase to ensure maximum benefits are derived. Starting early improves designer and contractor quality control processes, makes the CxP part of the process, and identifies and helps resolve problems during design (when corrective action is the least expensive). During construction, commissioning can also provide benefit when the contractor has the materials and resources on site for efficient corrective action (minimizing post-occupancy rework and repairs).

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 The CxP It is the CxP’s role to lead the collaborative team effort in each phase of the project, balancing competing interests so that the owner’s needs and mission are not lost. To accomplish this task, a benchmark is needed. This benchmark is the owner’s project requirements (OPR) and the CxP should be involved with its development. The CxP acts as the owner’s agent during the design, construction and building acceptance process. Ideally, the CxP will be an independent third party hired directly by the owner to avoid potential conflicts of interest. The CxP can be an individual or outside firm, depending on the size and scope of the job. Preferably, the CxP begins work in the predesign phase of a project, prior to engaging the design team, and they develop draft commissioning specifications and a commissioning plan. The draft commissioning plan defines the team’s roles and responsibilities, suggested communication protocols, commissioning activities, and the schedule of activities. Because of the high level of responsibility for the success of the project, the CxP should be experienced. The further along the team is in the design and construction process, the more difficult and expensive changes become. Waiting until after predesign to define project end goals, occupant requirements, and team roles and responsibilities can lead to increased project cost. The easiest time to evaluate or change goals, objectives, and criteria is during the schematic design phase. This is also the best time to reduce the cost of any changes. The feasibility of implementing high-performance features declines sharply after the schematic design phase. Making significant cost-efficient changes ends when the project moves into design development. Historically, owners and contractors set up a contingency fund intended to cover the unpredictable cost of changes in a project. If the design does not meet the owner’s needs, the owner may be forced to accept the project as is, because changes needed to meet his or her requirements at that point would be too costly.

5.3

DOCUMENTS FOR THE COMMISSIONING PROCESS 

 The Commissioning Plan The Commissioning Plan defines the team’s roles and responsibilities, communication protocols, activities to be performed, and the schedule of those activities. Commissioning success is dependent on each team member’s understanding of what is expected of them and their conformance with the plan. The commissioning plan provides the owner with clearly defined roles and responsibilities for each team member for inclusion in contractual agreements. It is better to define these requirements early, before selecting and contracting the various project team members. After the project team selection, an owner will state the basic requirements of the project that form the starting point for the OPR and the architectural program.

 OPR The OPR is a written document that details the functional requirements of a project and expectations of how it will be used and operated. The OPR includes project and design goals, programming needs, measurable performance criteria, budgets, schedules, success criteria, training and operational requirements, any goals for attaining certification, and supporting documentation. It also includes information necessary for all disciplines to properly plan, design, construct, operate, and maintain systems and assemblies. Development of the OPR is often a key contribution of the CxP during the early phases of a building project. Many confuse the OPR with the building program that the architect would produce. The typical architectural program focuses on project floor area needs, adjacencies, circulation, cost, and structural predesign test results. The OPR, however, documents how the owner intends for this building to function and

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fulfills the needs of the owner and the occupants. For instance, an architectural program does not contain requirements for how the building will be operated. It also does not contain training requirements for operations and maintenance (O&M), or post-construction documentation requirements for the building, whereas the OPR does. Developing the OPR in conjunction with the architectural program reduces programming effort and provides valuable information to the designers that they typically do not have. In combination with the architectural program, the OPR provides a strong foundation for a successfully integrated design and delivery process, and also meets the building’s operational criteria. The OPR, however, should not duplicate information from the architectural program. The OPR only forms the basis from which the CxP verifies that the developed project meets the needs and requirements of the owner.

 The Basis of Design (BoD) The BoD document should not be confused with the OPR, rather it should describe how the project design meets those OPR requirements. This document should be submitted by the design team and outlines how they have designed the project to meet the goals of the OPR. The HVAC BoD would, for example, include details on the assumptions made regarding operating schedules and factors affecting the overall cooling and heating loads.

5.4

DECISIONS DURING THE COMMISSIONING PROCESS 

 Selecting the CxP As with finding a doctor, lawyer, contractor, or other professional, the key element is that the CxP should have experience in the types of systems an owner wants commissioned. A good CxP generally has a broad range of knowledge: including hands-on experience in O&M, design, construction, and investigation of building/system failures. CxPs must also be detail-oriented, good communicators, and able to provide a collaborative approach that engages the project team. As with hiring in any profession a request for qualifications (RFQ), a request for proposal (RFP), and an interview are good ways to narrow the candidates and find the one that is most appropriate for a specific project.

 Selecting Systems to Commission There are three main system categories that should always be commissioned: the mechanical, plumbing, and electrical systems. In addition, including the building envelope in the commissioning plan is often recommended. Commissioning of all systems using the whole-building approach has proven to be beneficial. However, because of budget constraints, owners may want to look at only commissioning systems that will yield the greatest benefit. For example, if the building project includes an on-site renewable energy system, that would be a definite candidate for commissioning. Depending on the functional requirements of a building and the complexity of systems, additional systems that may be commissioned include security, voice/data, selected elements of fire and life safety, irrigation and/or process water systems, energy or water monitoring systems, and daylighting controls. The IgCC/189.1 defines the systems that should be commissioned and is a good general guideline to follow. In other cases, the systems selected for commissioning may be specified by code or standard, such as projects conducted under the requirements of the IgCC/189.1 (ICC 2018a). Long-term owners have an advantage and can apply their experience to commission only those systems where they have historically encountered problems. There are many factors that define which building systems should be commissioned. It often depends on the associated risk of not commissioning a particular system. Insurance providers publish graphs of claims against design professionals by discipline. Interestingly enough, many of the litigation claims against architects are for moisture intrusion, thus indicating a need for building envelope commissioning.

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In addition, the U.S. EPA noted that during the initial concerns about sick building syndrome in the 1980s, the World Health Organization suggested that up to 30% of new and remodeled buildings worldwide may be the subject of excessive complaints related to indoor air quality (IAQ) (EPA 2019b). So, these are key areas to consider for commissioning. Commissioning provides several benefits, including risk reduction. For example, based on the specific local climate, the risk associated with not commissioning the building envelope is much less in dry regions such as Phoenix, AZ than they would be in Miami, FL. Based on the functional requirements, declining to commission the security systems in a conventional office building may have less risk compared to a federal courthouse. Some systems may be commissioned by the manufacturer’s installer or specialized professional, such as is the case with fire and life safety systems where specific licenses and certification are required. Some building systems are installed with oversight and field testing by the manufacturer (elevators, for example) and these systems do not normally require a third-party commissioning agent.

5.5

COMMISSIONING PHASES 

Commissioning for new construction projects can be broken down into six distinct phases: • • • • • •

Predesign Design Construction Acceptance Warranty Ongoing commissioning

 Predesign One of the greatest values of involving a CxP in the predesign phase is to develop a comprehensive OPR document and a preliminary commissioning plan that serve as the project benchmarks, guiding all project team members. In this phase of the project, the CxP can help provide valuable insight to guide the team toward a high-performance design. It is critical that these requirements are clearly defined (before development of the architectural program) so that all effort is focused on these objectives.

 Design Design-phase commissioning reduces the risks of change orders, accompanying construction delays and errors and omissions claims. The CxP provides consulting to and checklists for the design team to assist in the design quality control process. These checklists also inform the designers about the specifics the CxP will be focusing on during commissioning design reviews. They include items designers should check during the quality control process, the amount and type of information to be provided at each stage of the commissioning design review, and the designer’s assertion that items in the commissioning checklists are complete. Two or three reviews are common during the design phase. A typical design review process is as follows: 1. Written comments from the reviewers are provided to the design team and owner. 2. Comments are reviewed and the design team returns written responses. 3. Meetings are scheduled with the review team and the designers to adjudicate comments as necessary, allowing the owner to understand the issues and have an opportunity to provide direction.

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4. Design concerns, comments, and actions taken are recorded in the design review document. Changes are made as agreed and the commissioning review team verifies the change and closes the issue as appropriate. Changes to optimize building performance, daylighting considerations, system selection, and stacking/massing synergies can best be addressed during schematic design review (Stacking and massing are terms describing how the various portions of a building [particularly a larger-scale building] are arranged with respect to each other.) Review during design development allows the team to identify potential problems and constructability perspectives early enough to resolve many issues before the construction documents phase starts.

 Construction During the construction phases, the CxP conducts site visits and provides checklists to the contractors to assist them in their quality control process and, as in the design reviews, verifies that the contractor’s quality control process is documented and functioning well. These efforts significantly improve the chances that the systems being commissioned will need only minor modifications during performance testing and will reduce the delivery team’s efforts and costs. The CxP’s role during the construction phase is to: • • • • •

Review the essentially complete (95%) construction documents and submittals Develop and integrate contractor construction checklists Identify and track issues to resolution; develop, direct, and verify functional and performance tests; observe construction of commissioned systems Review the O&M manuals provided under the contract Oversee development of a systems manual

Prior to the testing of systems and equipment, the CxP ensures that the necessary prefunctional tests and observations have been completed. The prefunctional tests are those where the equipment installation is confirmed as ready to receive power. Often, the prefunctional test procedures are developed by the manufacturer and are then verified by the contractor and CxP.

 Acceptance After construction is substantially complete, the CxP verifies that the systems perform as intended through testing and helps resolve issues prior to occupancy. The functional testing phase of the commissioning process is often referred to as the acceptance phase and is the phase that is most commonly associated with commissioning. With designer and contractor input, the CxP develops system tests (functional tests) to ensure the systems perform as intended under a variety of conditions. Contractors under the CxP’s direction execute the test procedures, while the CxP records results to verify performance. The tests should verify performance at the component level through inter- and intra-system levels. Another practice is to have the contractors simulate failure conditions to verify alerts and alarms, as well as system reaction and interaction with associated systems. Testing and balancing (TAB) of HVAC systems typically is provided by an independent third party (not the mechanical contractor) and a recent trend is to sometimes include this under the commissioning contract. Problems identified are resolved while contractors and materials are still on site and the designers are engaged.

 Warranty After occupancy begins, buildings typically undergo a warranty phase that allows for fixing of any problems that arise with the building systems. Typically this warranty phase is for one year. The CxP

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takes on a vital role in this phase to assist the owner and operational staff in identifying and resolving problems, hopefully with the least interruption to the occupants during this critical period. During this time, the CxP monitors system performance and verifies that the operators understand all training that had been provided. The CxP assists operators in better understanding their systems and maintaining maximum performance, which helps prevent inappropriate modifications by the operators. Many systems cannot be fully tested until the building is occupied, or have seasonally operated systems. For example, the heating and cooling equipment can only be fully tested under seasonal design load conditions. There might be some system components that pass functional testing but, fail to perform as intended under actual load. These components must be identified in the warranty period and replaced or repaired as necessary. The CxP’s role in conjunction with the operational staff is to search out problems that only become evident under actual load. By having the CxP work with the operational staff during the warranty period, the operators gain valuable insight into how the building should operate and what to look for to ensure continued performance. This helps to overcome bypassing of system components and controls because of a lack of understanding of how the systems are intended to operate—a typical industry problem.

 Ongoing Commissioning An important part of high-performance design is verification that the goals defined by the owner are integrated by the design and construction team to achieve the owner’s objectives for the life of the building. Using the original OPR as a starting point, the OPR is converted to the current facility requirements (CFR), which documents the changes the owner needs to match the changes in their daily mission. The CFR provides the foundation to guide the future project teams in modifications needed to meet the changing needs of the owner/occupant. Ongoing commissioning provides the owner and operators with the tools necessary to efficiently manage financial and human resources to achieve desired returns on their investment, to optimize building performance, and to reduce environmental impact. Various forms of commissioning can be performed during the long-term operation of a building. These can include a regular auditing process or perhaps monitoring-based commissioning. Monitoring-based, ongoing commissioning provides regular monitoring and analysis of utility usage, system interaction, and operator performance. Additional discussion on ongoing commissioning after occupancy begins are given in Chapter 13.

5.6

ANSI/ASHRAE/IES STANDARD 202 

As the commissioning process moved into the mainstream within the industry, the need for a formal, code-quality standard for commissioning became apparent. ANSI/ASHRAE/IES Standard 202, The Commissioning Process for Buildings and Systems (ASHRAE 2018b) defines the specific details needed to establish and conduct a well-organized commissioning process for a project. The basic scope of this Standard is to provide “procedures, methods, and documentation requirements for each activity for project delivery from predesign through occupancy (and) operations.” The standard covers the following: • • • •

Overview of commissioning process activities Description of each process step’s minimum activities Minimum documentation requirements Acceptance requirements

Standard 202 describes, in legally enforceable terms, a very detailed process for how commissioning should be run, along with the activities and deliverables that are needed. It describes what should be

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included in the critical components for a successful commissioning process, such as the OPR, the commissioning plan, the BoD, how to conduct design and submittal reviews, the systems manual, and the commissioning report. The main part of the standard is fairly short, but more detailed appendices are included that provide extensive details and examples of deliverables.

Application for a Future Career Commissioning has grown significantly in popularity during the past few decades. Thus, the demand for professionals with the technical and personal skills needed to fully participate in the quality control process of commissioning has greatly increased. To work effectively as a commissioning authority, it helps to have some prior related experience (for example, as a building design engineer or in construction). It is possible to be employed in a professional position in commissioning directly following the attainment of a college degree in the building sciences, but one would start off under the direction of the lead commissioning authority (like many other professional positions in this industry). A prior internship with a design or construction firm would also be of help. The commissioning process can involve a good deal of field work during the construction process and the young professional entering the industry in commissioning should expect to be called on for this type of work. The early career professional will also work with the various parties (architects and designers, contractors, equipment suppliers, and so on) to obtain information and verify compliance with the OPR and BoD. Those interested in a future career in commissioning should look into additional training, resources, and certification programs. The following is a brief list of commissioning certifications by organization. •

•

• • •

Associated Air Balance Council (AABC) and the AABC Commissioning Group (ACG) • Certified Commissioning Authority (CXA) • Certified Commissioning Technician (CXT) Association of Energy Engineers (AEE) • Certified Building Commissioning Professional (CBCP) • Master's Level CBCP (CBCPM) • Certified Building Commissioning Firm (CBCF) • Existing Building Commissioning Professional (EBCP) ASHRAE • Commissioning Process Management Professional (CPMP) The Building Commissioning Association (BCxA) • Certified Commissioning Professional (CCP) • Associate Commissioning Professional (ACP) National Environmental Balancing Bureau (NEBB) • Building Systems Commissioning Certified Professional (BSC CP) • Retrocommissioning Certified Professional (RCX CP)

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University of Wisconsin • Accredited Building Enclosure Commissioning Process Provider (BECxP) • Accredited Commissioning Authority + Building Enclosure (CxA+BE) • Accredited Commissioning Process Authority Professional (CxAP) • Accredited Commissioning Process Manager (CxM) • Accredited Commissioning Process Technical Service Provider (CxTS) • Accredited Green Commissioning Process Provider (GCxP) • Qualified Commissioning Process Provider (QCxP)

Discussion Topics, Exercises, Investigation Study Topics, and Assignments For Class Discussion: 1.

2. 3.

4. 5.

Describe some of the key differences between the commissioning of buildings as a quality control process and how quality control would be done for a typical manufacturing operation, such as in the design and manufacturing of a car. Explain why the OPR is considered the starting point for the commissioning process. Should all buildings be commissioned, regardless if they are considered a highperformance building or not? If not, then what criteria should be used to determine which buildings should or should not be commissioned? What percentage of the total project budget should be devoted to commissioning? What is the rationale for encouraging or requiring that the CxP be independent from the design and construction team, preferably under contract directly with the owner? Are there times and situations where a contractor, who has a vested interested in their work being accepted as good, might be allowed to commission their own work? What criteria would you think should be considered to allow this? In-Class Exercises:

1.

2. 3.

List the key systems that should be considered for inclusion as part of a commercial building commissioning program. Which of these would you consider vital to include, and which should be considered more on a case-by-case basis depending on the situation, budget, and so on? List five key tasks that a CxP would typically be responsible for in a highperformance building project. Create an argument as to why commissioning would be more important in ensuring successful completion of a large complicated project, such as a new hospital, compared to a small simple retail facility?

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4.

Why do you think some of the standards, codes, and certification programs require or recommend that commissioning only has to be implemented on buildings over a defined size (e.g., 5000 ft2 [500 m2]) instead of requiring this for all buildings? For Further Investigation and Study:

1.

2. 3.

Explain the differences between fundamental commissioning and enhanced commissioning as defined by the Leadership in Energy and Environmental Design (LEED) program. How do these differ from the concepts of building acceptance testing and building project commissioning as used in the IgCC/ 189.1? Imagine that you are with the campus architectural team for this university or college. Write an OPR for a new classroom building on this campus. Investigate a famous serious building failure that has occurred (for example, the Hyatt Regency Hotel walkway collapse in 1981 or the New York Mets replacement ballpark in 2009). What were the major issues with this case? How could have commissioning prevented these problems?

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6 Sustainable Sites: Locating the Project As part of the increased awareness of sustainable or high-performance building design practices, design professionals are becoming more cognizant of the work done by disciplines outside their own. For example, the building site and its location may seem foreign or not as important to an engineer responsible for the design of the lighting system or selection of building materials. However, those involved with the design of high-performance building projects should have at least a basic knowledge of all aspects of the design issues and associated implications from all disciplines and topics. This is especially important when considering the opportunity to find synergies in design where a decision can aid the performance of more than one system or when difficult choices need to be made to accommodate a budget.

6.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: • • • • •

Backlight, uplight, and glare (BUG) Best management practices (BMP) Greenfield, greyfield, and brownfield sites Solar reflective index (SRI) Urban heat island (UHI)

Reflection Exercise: Why Focus on the Building Site and Surroundings, and What Should we Focus On? The following exercise will aid understanding of issues associated with the sites and location of high-performance buildings. Think a little about each of the following topic areas associated with the site and location of a building. List why each of these is important in determining the overall sustainability or high performance of a building. • • •

Site location in relation to the local built and natural environment(s) Site landscaping Exterior lighting

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• • • • •

Stormwater management Building orientation Preservation or restoration of any natural vegetation or ecosystems on site Potential effects on nearby environmentally sensitive areas, such as streams or waterways Pedestrian connectivity to neighborhood services and community amenities

In most developed countries, local and regional agencies determine the allowable building use, site placement, density, height, parking, and site access. Local regulations are designed to, as a minimum, provide for compatible uses while addressing site connectivity, stormwater management, and environmentally sensitive areas. Depending on the region, these regulations can be fairly strict or more lenient. However, this is primarily a local or regionally derived decision based on long-term community goals and master plans. The first two sections of this chapter discuss key issues associated with the building site and location that a high-performance should take into consideration. The last two sections summarize how these issues can be addressed by high-performance buildings in design, construction, and operation, with a brief discussion on existing high-performance certification programs and codes.

6.2

LOCATION OF THE BUILDING PROJECT 

The building’s location may be allowable under local minimum codes or regulations, but not desirable for a building project that strives to be high performance. In fact, with most of the concepts concerning the building project location and overall site, the concept of high performance needs to be extended beyond just the minimum codes. High-performance design not only considers aspects internal to the building and its operation but also focuses on how the building integrates with the site, overall environment, and society as a whole.

 Community and Connectivity Consider a highly efficient office building with many sustainability features incorporated, but where the project developer has decided to build in a rural or more remote setting. Would that building be considered truly a high-performance building if all the occupants or visitors to the building had to drive private vehicles to the site each day? There is no right or wrong answer to that question, as all projects are unique, but transportation to the site is certainly a consideration. Thus, urban sprawl is just one more topic for consideration for a highperformance building and for ultimately moving toward a more sustainable built environment. Urban sprawl affects more than just environmental impact considerations; it affects human issues such as quality of life. When selecting the site for a building, the occupants or building users need to be considered. What is their commute time? What are their options for transportation (e.g., personal vehicle, public transportation [bus or train], bicycle, or walking)? As can be seen, the decisions and issues associated with this topic go well beyond just the design of the physical building structure and systems.

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 Greenfield, Greyfield, and Brownfield Sites The site is one of the earliest decisions to be made for a building project. The owner may already have a property selected and may just be deciding what to do with it, or there may be a specific building project in development but with several choices on where to locate the project. Sometimes it may be best to locate the project on a greenfield site (a location that has not been developed yet). However, just as it is more desirable to reuse and renovate an existing building rather than tear down and rebuild, it is also more desirable to locate the building on a site that already had been developed in the past, commonly known as a greyfield site. The opportunity may arise in some situations to develop the building project on a site that was formerly used for industrial or other similar purposes (a brownfield site). While it is good to reuse this type of land, care must be taken to avoid disturbing potentially contaminated soil. The first step in the due diligence process is to perform a Phase I Environmental Site Assessment (ESA). The Phase 1 ESA involves an initial evaluation of the potential for soil contamination, ground and surface water quality, and the potential for hazardous materials such as asbestos or lead-based paint in materials contained within existing buildings. This process includes site inspections, a review of past historical records for use of the property, and so on. If contamination (or potential contamination) is found to exist, a Phase II assessment should be performed and appropriate remediation completed. Although the context of an ESA originated in the United States, other countries have adopted a similar approach (ASTM 2013, 2011).

6.3

BUILDING EFFECTS ON THE SITE AND REGION 

The building project has the potential to affect the site and surrounding region in a number of ways. The building may have a positive contribution, but often the design team’s focus is to minimize or mitigate potential negative impacts. This section outlines key issues where a building can have an affect on the project site or the nearby region, either with new construction or an existing renovation.

 Urban Heat Island (UHI) Effect The UHI effect is the phenomenon of urban areas having ambient air temperatures higher than the surrounding rural areas in the same region. This is a complex topic, and the contributing factors to the UHI are many. Thus, high-performance building rating systems, standards, and codes have long recognized UHI as an essential consideration. These programs commonly address one of the main contributors to the UHI effect, the tendency of buildings and their associated site hardscape areas to absorb and retain heat from the sun. Hardscape refers to materials used in the landscaping and other modifications on the site that are not horticultural elements. These can include items such as pavement, retaining walls, or walkways. In some circumstances, the UHI effect may be considered a good thing. For example, if the UHI effect in a major metropolitan area means that precipitation falls as rain rather than snow, motorists in that area may be thankful. However, that same UHI effect in summer means that every building’s air-conditioning system must work harder to provide required cooling. The additional load placed on the system means additional thermal heat contributed to the ambient air and the additional energy consumption. For example, a simple, air-cooled air-conditioning unit operating with a 100°F (38°C) ambient air temperature will have approximately 10% lower compressor power input than a comparable unit providing the same cooling capacity and operating in an ambient air temperature of 105°F (40°C). Air-conditioning units produce anthropogenic waste heat. Anthropogenic heat is that which is rejected by building air-conditioning systems, transportation, and industrial processes into the environment. This heat does not just disappear into thin air, especially in dense urban environments, but rather contributes to overall higher urban temperatures. Outdoor condensing units connected to the air-conditioning system reject all the thermal

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energy from inside the building (plus the energy used to power the refrigeration system that provided that cooling) to the outdoor air. Thus, whatever can be done to reduce energy consumption and improve efficiency of HVAC and refrigeration systems can also have the positive benefit of reducing the overall UHI effect. There are many other contributors to the UHI effect that are beyond the control of the building designers. These include items such as industrial activity and motor vehicle transportation. The UHI effect should therefore be looked at as a regional issue and not just evaluated using cost effectiveness of reductions in an isolated building’s heat gain and its affect on the cooling load.

 Stormwater Management, Erosion, and Sedimentation Development of land area for buildings and the associated infrastructure has increased the area of impervious surfaces (building roofs, parking lots, roads, walkways, and so on) that contribute to increased surface runoff into waterways. That increased runoff is often the cause or a significant contributor to flooding problems downstream. Stormwater and erosion control is therefore a significant concern. Many localities have regulations and guidelines to minimize the impact of impervious surfaces, but these vary in effectiveness depending on enactment of regulations, level of enforcement, and clarity of expectations. In addition to the quantity of the water runoff, a high-performance building design should also work to improve the quality of runoff in terms of erosion and sedimentation control and preventing potential contaminants on the site from entering the waterways. Contaminants may have already existed on the building site from prior activity, but contaminants can also possibly be left on the site as a byproduct of building construction. This is one area where design and features of the building project can provide a measurable positive contribution to the environment or at least where several options exist to minimize the negative impact.

 Exterior Lighting Similar to UHI, the design of exterior lighting levels and lighting fixture selection for a green building involves both consideration of lighting power (for total energy consumption) and the effect of the building and its systems on the surrounding locality. In the case of exterior lighting and the building site, it is also a matter of how the lighting is directed to the area intended to be lit. A general definition of pollution is the introduction of something into the environment that causes harm or degradation to the environment. Thus, light can indeed be a source of pollution if a building is responsible for emitting light beyond the property boundary at sufficient levels to cause a negative effect elsewhere. A classic example would be a shopping mall located adjacent to a housing development. The mall’s parking lot lights may be on all night at a high level for security purposes. However, homes with bedroom windows facing directly toward that mall may require the installation of darkening shades on windows to avoid disrupting the residents’ sleep. This same scenario also commonly occurs with street lights, retail establishments, medical facility parking, and so on. Excess exterior lighting or light pollution impacts not only nearby humans, but also affects the natural world by disrupting and confusing wildlife. It also adds to the overall urban glow that reduces the ability to see stars at night—for this reason, many people have never seen the Milky Way with their own eyes. Depending on the situation and location, the importance of exterior lighting and light pollution may range from vital to inconsequential. If the building project is located near a park or other natural space where the additional nighttime lighting would be an annoyance or worse, then there is a need to have stricter control on the lighting used. If this building is located in a major urban core with already significant nighttime lighting in the surrounding environment, then there is less need for strict control (although factoring these concerns into the building design would be worthwhile).

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 Noise Pollution Building systems generate noise (for example, chillers, cooling towers, or condensing units). A highperformance building project should evaluate the potential impact of the systems involved and include plans for mitigating those impacts.

6.4

SUSTAINABLE SITES AND HIGH-PERFORMANCE BUILDINGS 

This section outlines concepts and techniques for how building design and installation can minimize the effects on the overall site or region, and perhaps even improve the site’s environmental characteristics. These concepts apply to both new construction and existing building renovations.

 Stormwater Management and Mitigation Techniques The best designs for minimizing stormwater impact will result in no more surface runoff from that property than would have occurred from a natural, undisturbed landscape at the same location. This can be achieved by a combination of one or more of the following design features. Maintaining a Larger Vegetated Percentage of the Property. Maintaining as much as possible of the property with some form of vegetated surface is a prime consideration. However, some properties offer limited, if any, potential for strategy, so additional measures are needed. Minimizing Unnecessary Impervious Surfaces and Compaction of the Soil. Impervious surfaces (such as roofs and concrete or asphalt pavements) do not allow precipitation to infiltrate into the soil. In addition, during the site preparation and construction process, the soil may become compacted. Compacted soil reduces the ability for water infiltration and increases surface runoff. By careful planning and construction management, the amount of unnecessary compaction that occurs can be minimized. The site development planning should also consider the use of porous pavement or pavers or other methods to increase the rainfall absorption on site and thus minimize runoff. Porous pavements are concrete systems that are designed to allow precipitation to drain through while still retaining structural strength sufficient for traffic. The performance of a test installation of porous pavement during a hard rainfall is shown in Figure 6.1. Notice the water runoff on this parking lot with free water flowing across the surface. The six parking spaces in the center have porous pavement installed and have no standing water—all the water draining toward them seeps through to the soil. Rain Gardens or Retention Basins. Retention basins and rain gardens are low-lying regions on the property located and designed to collect surface runoff from surrounding impervious surfaces (such as parking areas). They slow rainfall runoff enough to allow a significant portion of that water to naturally infiltrate into the soil or leave by evaporation or transpiration from plants in the rain garden. Retention basins are areas designed primarily to collect the runoff water, with or without consideration for the aesthetics of that feature. Rain gardens provide a similar function as a traditional retention basin or pond, but with the additional benefits of providing a more natural landscape look (see Figure 6.2) and avoiding some of the negative aspects of retention ponds such as liability concerns and the need to fence the area off. Rainwater Harvesting. Rainwater collection for later use in the building or on the site as irrigation water has two sustainability-related benefits. On-site collection and storage of rainwater from rooftops and impervious surfaces means much less water running off the property and possibility contributing to stormwater problems downstream. (This is therefore a sustainable site issue.) If the collected water is used to displace potable water (for example, as makeup water to a cooling tower), then rainwater harvest-

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Figure 6.1. Example of porous pavement performance during heavy rainfall. Photo courtesy Stephan Durham (still from video)

Figure 6.2. Example of rain garden to manage stormwater runoff from a building roof drain.

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ing also contributes toward water efficiency. Further discussion on the use of rainwater and other recovered or reclaimed water sources as a substitute for using potable water in a building is given in Chapter 7.

 Managing the UHI: Cool Roofs, Walls, and Hardscape Materials There are many methods the building designer has available to help minimize the contribution of a building project to the local UHI. One of the primary methods includes the use of materials that have a higher solar reflective index (SRI). The SRI is a rating metric that is based on the ability of a material to absorb the sun’s heat (in terms of the absorptivity of the material) as well as its ability to lose heat by thermal radiation, which is determined by the thermal emissivity of the material. The rating ranges from 0 to 100, with an SRI = 0 being a black surface (equivalent an initial solar reflectance of 0.05 and initial thermal emittance 0.90) and an SRI = 100 being a white surface (initial solar reflectance of 0.8 and initial thermal emittance 0.90). Note that the thermal emissivity value of many materials in the infrared wavelengths is often around 0.9 regardless of the surface color. The use of higher-reflectivity materials on roofs and walls will have varying impact on the building heat gain, depending on how thermally coupled the building interior is with the exterior structure. In some structures, the reduction in heat gain to the overall building cooling load is practically insignificant, while in other cases they can cause a noticeable reduction in overall cooling load. An illustration of how cool roof technologies work is shown in Figure 6.3. As the building materials age and are exposed to the environment, their properties may change. For example, reflectivity may decrease. These changes occur due to potential degradation of the product materials, or simply dirt accumulation on the material surface. High-performance building certification programs codes often set minimum SRI based on 3-year aged levels rather than when they are brand new. These would be closer aligned to the values expected during normal building operation over time.

Figure 6.3. How cool roofs work.

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However, high-performance building concepts, standards, and certification programs are concerned not only with the building heat gain, but also with the contribution of the building structure and associated hardscape with the UHI effect. For example, the selection of a roof with a lower solar absorption rate reduces the heat gain into the building, thereby potentially reducing the size and expense of operating the system, but also reduces the heat rejected to the surrounding environment. In fact, much of the benefit from measures that reduce the UHI effect is experienced by all in the local region and not by just that particular building’s operation and performance. These are positive externalities from implementing measures to reduce the heat island impact. Thus, this is a site and local environment issue, rather than strictly a building energy issue, although tools such as cool roofing materials can affect both. This is, therefore, a subject that is a benefit to society as a whole and should not be overlooked when evaluating options in preliminary building design. Other methods for addressing the contribution of a building to the UHI include the use of shading (such as from vegetation) to prevent a building wall or the hardscape from absorbing the sun’s heat and keeping those surfaces from getting hot and contributing to the overall UHI effect. In other situations, the design team should be aware of the potential for causing unintended consequences when using high SRI materials. It is possible that a high SRI roof may end up causing a higher heat gain through the windows of an adjacent building through reflection of sunlight, perhaps causing thermal comfort and overall HVAC system operational problems there. Some high-profile problems have been reportedly caused by high reflective metal surfaces or structures on buildings (such as damage to sidewalks and vehicles on the streets below), but these were primarily caused by architectural façades— these issues are explored further in the Discussion Topics section at the end of this chapter. These potential negative impacts help highlight the need to look at every building project not in isolation, but rather as part of the surrounding neighborhood and environment.

 Green or Vegetated Roofs and Terraces Green roofs are described in this separate section because they have the potential to provide benefits in multiple areas, such as addressing the UHI, stormwater management, and improved ambient air quality. Green roofs are roofs where a layer of soil and vegetation is planted on top of an impermeable roof with a waterproofing layer in between to maintain the building envelope. Green roofs can also provide benefits to the site in terms of potential habitat for wildlife as well as a positive effect on the building occupants and surrounding environment. Green roofs provide the ability to absorb at least a portion of the precipitation that falls on the roof, terrace, or plaza. The amount collected and stored depends on soil depth, soil condition before the storm event (whether dry or already containing some water), and the type of soil in the green roof system. Green roofs have been recognized by green building certification systems, standards, and codes as having a positive effect of reducing the local UHI, but the amount of this benefit depends on the moisture content of the soil and any shading from vegetation on the green roof soil surface. They do provide additional environmental benefits, but can also be a source of additional water consumption if not properly designed. To minimize the negative aspects, the design team should select native plants to minimize or eliminate the need for supplemental irrigation and, depending on the green roof type, the design may need to consider the load bearing capacity of the roof (especially for existing buildings). There is also the potential concern for moisture problems to the building, and therefore the design team should pay careful attention to the need for installation of waterproofing material, drainage, and so on. An example green roof placed over the top of a parking facility can be seen in Figure 6.4. This installation provides the benefits of a native vegetated area as well as a pleasant space for people.

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Figure 6.4. Example of green roof planted with native or adapted species. Green roofs are classified as extensive or intensive depending on their design and construction. An extensive green roof is one that is essentially external to the building structure. These will have shallower soil depths (between 3 and 6 in. [7 and 15 cm] soil depth) and are thus lighter weight but with more limited options for the vegetation to be included. Extensive green roofs could even be installed in the form of pans with soil and vegetation already included and placed on the surface of a conventional building roof. In contrast, an intensive green roof integrates the green roof directly into the building structure and design and can thus accommodate greater soil depths. This adds significant load to the roof structural requirements but also gives more options for vegetation types and provides additional stormwater collection potential. Regulations and guidelines for green roofs are available in some countries. The first one with widespread use was published in Germany (FLL 2004). Other examples include the UK guidelines on best practices for the design, installation, and maintenance of green roofs (NFRC 2014) and ASTM Standard E2400 (ASTM 2015). Green roofs are more common in Europe than in other areas of the world. In Germany, the market boomed beginning in the 1980s and recent estimate place the total installed green roof area in Germany at between 1 and 1.5 billion ft2 (100 and 150 million m2) (Dongfang 2017). More than 75 European municipalities currently provide incentives or requirements for green roof installation. Copenhagen, Denmark mandates that all new flat roofs at or under a 30° pitch have a green roof. The decision to install a green roof should take a number of factors into consideration; one item to note is that Europe has more temperate climates compared to the harsher summertime conditions expected in installations in much of the United States.

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 Light Pollution Control There are two general ways this problem can be addressed, and they are not mutually exclusive. One way focuses on energy consumption and addresses this with an overall restriction in the total amount of lighting used and how that lighting is controlled in terms of turning on and off the lighting. This is the approach used by energy standards and codes such as ANSI/ASHRAE/IES Standard 90.1 and the International Energy Conservation Code (IECC). Another way is through the specification and use of lighting fixtures that direct the light to only where needed and thus minimize the potential for light to escape beyond the property line of that building project. A process has been developed by the Illumination Engineering Society (IES) and the International Dark Sky Association to measure the backlight, uplight, and glare (BUG) rating of a lighting fixture. Backlight is light that is in the 90° arc behind and below the lighting source. Uplight is light that escapes behind the fixture, which is, for the most part, wasted. Glare is any light directed in the 90° direction in front of the light fixture (this is sometimes referred to as frontlight). The various features of a BUG rating are illustrated in Figure 6.5. Lighting manufacturers can rate their products-based lumen limits specified in IES Standard TM-15, Luminaire Classification System for Outdoor Luminaires (IES 2011). To prevent light from escaping the building project property boundary to areas that would be adversely affected by that light, the lighting design should specify fixtures that meet certain BUG ratings, with these levels depending on the situation and location. The building project lighting zone type should first be identified based on the technical criteria set by the IES. Additional discussion of the lighting zone types is given in the later Building Certification Programs and Code Requirements section.

Figure 6.5. Illustration of the various aspects of BUG ratings for exterior lighting.

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 Survey of the Building Site, Habitat Protection, and Restoration Unless the building project is located on a site with essentially zero lot-line boundaries (the building footprint is located up to the property boundary) and minimal or no local natural habitats, the building project team should conduct a survey of what is on the existing site. This should be part of an overall site survey of the topography, hydrology, climate, vegetation, soils, human use, local ecological habitat (particularly if this is a greenfield site), and potential human health effects. After the survey is complete, there should be a site preparation plan and design for after construction that will include methods for the following: • • •

Elimination of any invasive plant species on the site Improving the site habitat to reflect natural areas in that region Providing a positive experience for the building occupants and users by providing views looking outside and providing opportunities for engagement with nature

 Minimization of Impacts During Construction One of the greatest impacts a building can have on the local environment is during construction. Even if they are temporary, the effects can potentially be large. Effects include topsoil erosion and sedimentation runoff, native plant destruction, air pollution from construction vehicles (particularly from idling vehicles), noise, and dust or particulate emissions. A high-performance building project is expected to have a well-thought-out and documented stormwater and erosion control plan for use by the construction team. This plan should be communicated to all relevant contractors and compliance with that plan should be included in the contractual language for each contractor. The U.S. Environmental Protection Agency (EPA) has a good reference document on how to develop a stormwater pollution prevention plan (EPA 2007).

6.5

BUILDING CERTIFICATION PROGRAMS AND CODE REQUIREMENTS 

This section provides a brief outline of how building certification programs (using LEED as an example) and the International Green Construction Code (IgCC/189.1) address the issues raised in this chapter. Protecting the building site must be an important focus for any high-performance building. Building certifications and codes include credits and requirements that address the key issues discussed in this chapter. Rather than focusing on first the certification programs and then the standards or codes, we briefly discuss how these are addressed in each key topical area.

 UHI Effect Building certification programs, standards, and/or codes all tend to include similar methods for limiting the UHI, such as specifying the SRI values of roofs and hardscapes or for hardscape shading. Higher SRI values are required for flat or low-sloped roofs than for steep-sloped roofs because of the types of roof covering materials generally involved with those different structure designs. The roof design should use materials with a 3-year aged SRI value of 64 for low slope (with a slope ratio of less than 2:12) and 25 for high-slope (slope ratio greater than 2:12) roofs. There is some discussion in the industry as to what climate zones the higher SRI materials should be used in, due to concerns about moisture and so on, but in general these should be used or at least considered for buildings in ASHRAE climate zones 0–4 (ASHRAE 2013). The IgCC/189.1 also includes provisions for the lower portions of building walls to be shaded or to have a minimum SRI value for opaque wall materials (ICC 2018a).

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 Stormwater Management Existing high-performance building standards and codes or other building certification systems approach stormwater management from various perspectives. One approach is to specify or require the building project achieve a particular performance basis in terms of stormwater management. This approach seeks to address the amount and quality of stormwater runoff based on comparison to a set criterion. For example, a target could be to end up with the post-development runoff amount not exceeding that which would have occurred from the same site if left in an undisturbed, predevelopment state. A performance approach is used by the U.S. Green Building Council (USGBC) Leadership in Energy and Environmental Design (LEED) rating systems. Performance is what ultimately counts, but this is achieved by the actual design and selection of specific measures. An alternative approach could be one that is prescriptive in nature. Instead of specifying one particular performance criterion to be achieved, a prescriptive approach would require the inclusion of best management practices (BMPs) that have been proven to address problems caused by unmitigated stormwater from the built environment. This approach is identified as being prescriptive, as it prescribes specific technologies or practices to be implemented. Some of these practices were briefly outlined in the sections above.

 Exterior Lighting BUG ratings make addressing this issue fairly simple; the design team just needs to ensure that fixtures with the proper rating for this location are specified. There are different lighting zones defined in the Illumination Engineering Society (IES) Technical Memorandum (IES 2011). The concept is that the human eye will adapt and less light is needed in darker conditions while more light is needed in an area where light already exists. The ratings are also more stringent in areas that the light pollution will cause more ecological harm. Lighting zones range from LZ0 (Undeveloped areas within national parks, state parks, forest land, rural areas, and other undeveloped areas) to LZ4 (high activity commercial districts in major metropolitan areas).

Case Studies The following case studies address issues beyond just their sites and locations. While the focus in each is on the sites issue, they provide interesting insight into overall realworld problems with developing truly high-performance building projects. The Bitter Battle to Turn an Old Factory into a 21st Century Eco-Village Redevelopment projects of old facilities, such as a closed factory site, often bring up competing perspectives from the residents in the area. One example is case of what to do with an old automotive manufacturing plant in St. Paul, MN, that closed in 2011 (Walljasper 2018). 1. 2. 3.

What are the key positives to this redevelopment project mentioned by proponents? What are the main drawbacks mentioned by the opposition? Can these two sides be resolved to a solution that all can accept (i.e., is there a possible common ground solution)?

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San Francisco Public Utilities Commission Headquarters Building The main webpage for this building is at: http://sfwater.org/index.aspx?page=583. (SFWater 2018) Besides the many sustainable features on this project, an interesting look at how this building is designed to have an artistic appeal to those on the outside is shown in the video: www.youtube.com/watch?v=lNjTPnLspgM (kevinsyoza 2012). Not all that was promised with this building has been successful. An article from the San Francisco Chronicle highlights some of the problems (Johnson 2016).

Additional Resources for Further Study Several additional study and reference documents are available www.ashrae.org/HPBSimplified. For this chapter, this includes the following: • • • •

at

Rain gardens File name “Rain Gardens” Green roof systems File name “Green Roof Systems” Developing Your Stormwater Prevention Plan (EPA 2007) www3.epa.gov/npdes/pubs/sw_swppp_guide.pdf Guidance Manual for Developing Best Management Practices (BMP) (EPA 1993) www3.epa.gov/npdes/pubs/owm0274.pdf

Application for a Future Career It should be apparent by now that professionals from many disciplines are responsible for design decisions that influence the overall performance of a building with respect to the site and location. For those that wish to eventually work on high-performance building projects, being aware of the interconnected nature of the building design with the local and regional environment is important. The location of the building will often be determined by other factors, such as local land use planning or zoning regulations, but it is still important for the high-performance building professional to know of the socialpolitical-economic factors that are involved. Specific professional titles that have a job component specifically related to the site include: land scape architect, environmental engineer, hydrologist, and civil engineer.

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Discussion Topics, Exercises, Investigation Study Topics, and Assignments For Class Discussion: 1.

2. 3.

4.

5. 6.

7.

Imagine that you are part of a management team trying to decide on the location of a new building project. You have been offered a great deal on an existing site, but the site is rumored to have chemical contamination on it from earlier uses (you are not sure). The alternative is a greenfield site located in a region of the city that is growing. What are the issues that you would want to consider and get answers to before you make your decision on the location? What can your university campus do to help encourage connectivity of the campus with the surrounding locality? Would green roofs perform well and add to the environmental quality in the location where this class meets? Consider all aspects, such as the local climate, the benefits to the campus occupants, and so on. Where might you suggest a green roof be considered? How important is it to include the topic of exterior lighting in high-performance building designs compared to the other issues concerning the building site and region? Are there specific instances where this is a problem either on this campus or in the local vicinity of the campus? Discuss the transportation options for students, faculty and staff commuting to your campus. In what ways could these be improved to make them more sustainable? Rate the practicality of each. Should local community governments direct or control where new development is to occur, for example, to encourage or mandate development oriented around public transportation? If yes, what topics should be under primary consideration by the governmental agencies? If not, are there some areas that should be considered for regulation, at least to some extent, and how would the planning or decisions for new development be undertaken? What are the key aspects that would go into the design of a parking lot that includes pervious concrete or pavement? What are the key components for the mixture and application of that concrete? What other design factors need to be considered? In-Class Exercises:

1.

Is your university campus in a location where the UHI effect is significant (with a negative impact)? Develop an outline of a plan for how your university campus can minimize that impact. Do these ideas require significant changes to the overall infrastructure or operation of the university?

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2.

3.

4.

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Make a quick “back-of-the-envelope” estimation of the increased energy consumption for air conditioning on your campus caused an UHI effect of 5°F (about 3°C) compared to if there were no heat island effect. Note: this will required a good deal of assumption-making and guidance from the instructor. Take a walk around the building where this class meets. Identify items included in the building installation that have a positive impact on the site and location. Identify areas where the building seems to be having a significant negative impact. One way that high-performance buildings can help minimize impacts on local air pollution and other issues is to provide electric vehicle charging stations on site. Make a list of potential (or existing) locations on this campus that include or could include electric vehicle charging stations. How do you propose that these locations be paid for? Should the charging be free? What policies would you create if you were in charge of implementing this opportunity on campus? On-site electric vehicle charging is discussed further in Chapter 16. For Further Investigation and Study:

1.

2.

3.

4. 5.

Investigate the pros and cons of the installation of pervious concrete. Would this type of material work well on your university campus? Why or why not? Where would be good candidate locations for pervious concrete? Why do you think this is not more widely used in practice? Investigate the stormwater management practices for your university campus and locality. Do these seem to follow best management practices (BMP) guidelines? Further details on stormwater BMP are included at www.ashrae.org/HPBSimplified and listed above. In what ways are do these measures contribute positively? Are there any areas that the campus needs to focus more on? What is the recent history in your local environment in terms of stormwater-induced flooding? Investigate some recent high-profile building cases where an actual built building has had unforeseen (at least to the initial design team) consequences. For example, consider the “Walkie-Talkie” skyscraper in London (technically the 20 Fenchurch Street building) or the Walt Disney Concert Hall in downtown Los Angeles. What were the issues involved? Could these have been foreseen and avoided? What were the solutions to resolving these real-world problems? Investigate the land use planning and zoning policies for the state and city at this campus location. Do these policies encourage or discourage suburban sprawl? Investigate further the pros and cons of white or cool roofing. Are there particular climates where cool roofing is not desirable? Identify five existing projects online that use cool roofs and discuss if these are appropriate applications. If possible, try to identify if there are installations of such roofing currently on your campus and how these are performing.

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6.

Research the various mechanisms that some cities have taken in the United States on planning and development of transportation options. Compare and contrast the methods used as well as the results. Example cities to consider could be: Atlanta, GA; Portland, OR; Houston, TX; Charlotte, NC; and Washington, D.C. Potential Design Projects:

1.

2.

Investigate a location on your campus that would make a good location for a rain garden. Prepare a sketch and diagrams for what this garden would look like—this would include the size and location, the site preparation needed, the plant species that would work well in this garden, and so on. Are there any negative consequences if this rain garden were to be installed? Identify a parking lot or similar location on your campus that would be a good candidate for the installation of permeable pavement or pervious concrete. Prepare the design sketches for how this installation would be done. Determine how the water collected would be handled and size the key installation layers and components.

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7 Water Efficiency and Utilization Access to clean water is one of the most preeminent topics in global society. Some have called water the “new energy” in terms of its importance to society. Take, for example, the recent experience of Cape Town, South Africa. A drought that began in 2015 resulted in the city being on the brink of depleting their reservoirs by 2018, even in spite of implementing a general water conservation program after droughts in the years 2000–2004. Buildings have an important role to play in terms of overall water consumption, particularly within urban environments. On a small-scale (individual buildings), the effect may not seem that significant, but the combined impact of all buildings in a community is large.

7.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: • • • •

American Society of Plumbing Engineers (ASPE) American Water Works Association (AWWA) Evapotranspiration (ET) and reference evapotranspiration rate (ETo) Greywater

Reflection Exercise: Why is Water Efficiency an Important Part of a High-Performance Building? Where Does Water Come from and How is it Used? To properly understand the importance of buildings in the overall efficient use of water, it is important first to make a list of how water is used. Make a list of all the areas where water is used on your campus (or, alternatively, in your personal residence). Highlight those you think have significant potential for reducing consumption without negatively impacting the quality of life. How could these reductions be implemented? It is helpful to look at the overall water consumption data for typical developed economies. For example, check out U.S. federal government data, such as this from the U.S. Energy Information Agency (DOE 2014a).

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Commentary Water is an important resource that deserves attention as part of the design criteria and operation of buildings. Water is used in a number of ways within commercial buildings, varying depending on the type of usage and occupancy of the building. This chapter will help you understand where water is used and methods that can be adopted during design and operation to reduce the overall water footprint of a high-performance building.

7.2

THE VALUE OF WATER AND WATER EFFICIENCY 

The earth has a fixed amount of water contained in various forms, such as in oceans, glaciers, underground aquifers, precipitation, vapor, and embodied in living organisms. No water in any form leaves or enters the planet, with the exception of minuscule amounts entering from meteorites and leaving on space launches. The problem is not that there is an overall lack of water, it is just that in many places there is a lack of usable water. Water efficiency and conservation therefore continue to be critical factors in high-performance building design. In 2015, water use in residential and commercial buildings was estimated at 45.6 billion gallons (0.17 billion m3) per day, with nearly 13% of total worldwide fresh and saline water consumption occurring in the United States. This is substantial considering the U.S. population is only around 5% of the world’s population. Between 1985 and 2005, total water use increased less than 3%, while water use in the buildings sector increased 27% (DOE 2012). Efficient operational practices provide opportunities to save significant amounts of water in the building sector. A number of factors are expected to drive adoption of water-efficient products and methods. These include the need to reduce overall water use and withdrawal from water supply sources, the desire for lower operating costs, and increased government regulation through the development of new codes and standards. Cooling systems within commercial buildings account for approximately one third of the building’s water consumption. Commercial building HVAC systems can be a significant proportion of the total water consumption in a building, particularly if they employ a water-cooled chiller (refer to Chapter 8). To help address this issue, ASHRAE partnered with the American Water Works Association (AWWA), the U.S. Green Building Council (USGBC), and the American Society of Plumbing Engineers (ASPE) to develop a proposed new standard: Standard 191, Standard for the Efficient Use of Water in Building, Site, and Mechanical Systems. This new standard is projected to be formalized in late 2019 or early 2020 (ASHRAE SPC 191 2019).

 The Water-Energy Nexus The term nexus can be defined as a connection or series of connections linking two or more things. The water-energy nexus references the interdependent and inseparable nature of two of our most precious resources, water and energy. The consumption of energy and water are interrelated and this relationship is illustrated in Figure 7.1. This figure shows the flow of water and energy from the various supply sources and how much water and energy are used on an annual basis in the various sectors of the economy. Water consumption is listed in billions of gallons per year and energy is listed in quads per year. A quad is one quadrillion (1015) Btu. Water or energy flows from left to right in this diagram, first as it is extracted or generated and then how it is used. Note in some cases that there is an overlap or exchange, where water is involved with energy production or in other situations where energy is used to process and transport water—this represents the water-energy nexus.

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Figure 7.1. Energy and water flow diagram for the United States.

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The water use cycle involves considerable energy expenditures. Energy is needed to extract, treat, and transport potable water and to collect and treat wastewater. Electricity production from fossil fuels and nuclear energy is the largest use of water in the United States. According to the U.S. Geological Survey, electricity production in 2010 it accounted for 45% of total water withdrawal in the United States, requiring an average of 161 billion gallons (609 million m3) of water per day (Maupin et al. 2014). Although water used by thermoelectric power plants for once-through cooling systems is returned to waterways or lakes, it is returned at a higher temperature, leading to a greater evaporation rate and is thus indeed a net consumption of water. With approximately 8% of the global energy consumption being used for pumping, treatment, and transportation of water and approximately 15% of the world’s total water used for energy production, each resource (water and energy) will face rising demands and constraints as a consequence of economic growth, a growing worldwide population, and climate changes that affect water availability and energy consumption. Water and energy, in their various classifications, have generally continued to be viewed in individual independent silos, which has limited the adoption of integrated solutions. To properly address the challenges and opportunities posed by the water-energy nexus, emphasis on policy incentives and sustainable engineering solutions promoting optimal usage efficiency of each resource, as well as advanced technologies promoting both water and energy conservation, will be required.

 The Value of Water in Society According to the World Health Organization, more than 700 million people do not have access to improved water supply sources (WHO 2019). The amount of fresh water of sufficient quality suitable for consumption is not uniformly distributed. (For example, 20% of the world’s fresh water is stored in the U.S. Great Lakes, while elsewhere it is often nonexistent or in meager supply.) In addition, the relation of water availability relative to demand varies widely, as seen in Figure 7.2. Water stress is defined by the water demand compared to local availability of fresh water. Water must be somehow allocated to the world’s populated lands, many of which are undergoing rapid development. In short, it is becoming more and more difficult to provide adequate distribution of the world’s water supply to those who need it. In areas where water supply is not plentiful, an engineer focusing on high-performance design should take the total energy as well as water consumption required to operate the building or facility into consideration. While many of the measures to protect and preserve the world’s freshwater supplies are beyond a design engineer’s purview, there are a number of simple things related to buildings that can be done as part of a high-performance design effort.

7.3

WHERE WATER IS USED IN COMMERCIAL BUILDINGS 

How water gets used in a commercial building depends on the purpose and type of building. Figure 7.3 shows a typical breakdown of water use for various types of commercial buildings in the United States. Water is not consumed like energy or food; those are used up or converted and are not available for further use, while water may be withdrawn and used for some purpose and still remain in the ecosystem (but maybe in different form such as water turned to vapor through evaporation). The next sections cover major areas where water is consumed in commercial buildings. These include site water use for landscaping, internal use for domestic water consumption, and process uses such as HVAC systems or food preparation. The primary purpose will be on minimizing the use of fresh potable water. Using alternative water sources, such as collected rainwater or HVAC condensate, is an option to reduce the consumption of potable water. However, the initial focus should be on first getting the greatest possible overall reduction

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Figure 7.2. United States predicted change in water stress levels, 2040–2060. (NOAA 2013)

in water use, regardless of the source of that water. That is the most environmentally friendly option, and is most often also the most cost-effective.

7.4

SITE WATER USE 

Site water use refers to water used external to the building and on the building project property. Landscaping irrigation and water features such as fountains or swimming pools are the primary examples.

 Landscape Design The landscape architect plays a key role in determining how much, if any, water is required by the landscaping by selecting the plant species used. Ideally, the plants would be adapted to the local environment and not require any supplemental irrigation beyond perhaps an initial period for ensuring the plants are established. If it is necessary to include some plants that will require supplemental irrigation, then the landscape design should group those plantings together to minimize the area needing irrigation. A maximum percentage target of the improved landscape design (the portion of the site that will be reworked after con-

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Figure 7.3. Water uses in commercial buildings. (ASHRAE 2018c)

struction is finished) that includes plants which require irrigation should be established for the building project. The plantings be also be biodiverse to help improve the local ecological footprint of the site.

 Determining Irrigation Demand For situations where the landscaping does require the installation of irrigation, the amount used should be just sufficient to maintain health of the plants and no more. That amount is determined by the combined evaporation from the soil, intercepted water on the plant canopy, and the transpiration from the plants (also called evapotranspiration [ET]). Landscape architects base the amount of actual ET for each plant on a standard reference ET rate determined by the Penman-Monteith equation. This is a complex equation that gives a standard reference ET rate (ETo) and is derived from an energy and mass transfer balance given standard reference data such as solar radiation, temperature, humidity, and wind speed. This equation and calculation process is well beyond the scope of this book. For those wanting to dig a little deeper, there is an ETo calculator tool available from the United Nations Food and Agriculture Organization (FAO 2009). Estimates for the actual ET rates for individual plant species in a given location are determined based on adjustment factors for that species. A vital component for water conservation with the irrigation system is to water only when it is needed, not based on some arbitrary time clock or schedule. Thus, a smart control system design should be provided that shuts off the irrigation when either (1) a sensor detects that the water level in the soil reaches an adequate moisture level or (2) the irrigation system (plus any rainfall) has provided an adequate

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amount to make up for the ET from that site. IgCC/189.1 states that the irrigation control should provide no more than 10% above the maximum evaporation rate and defines an adequate amount to be 80% of the plants’ need (ICC 2018a).

 Choosing Water Sources for Irrigation Outdoor irrigation is an excellent opportunity for the use of reclaimed or recovered water in commercial buildings. The water does not have to exactly meet drinking quality standards in order to be used, thus rainwater, HVAC condensate, or other sources of greywater can be considered. More discussion on HVAC condensate is given later in this chapter. If greywater is used, then the local codes that govern its use must be followed. The codes in the United States follow the requirements set by the NSF/ANSI Standard 350, Onsite Residential and Commercial Water Reuse Treatment Systems (NSF 2017). This standard and the corresponding codes include aspects such as the level of water treatment needed and methods to protect from direct human contact.

7.5

INTERNAL BUILDING SYSTEMS 

Water conservation strategies save building owners money on their monthly utility expenses. Municipal water and wastewater treatment plants also save on operating and capital costs, and these savings would (in theory) ultimately would be passed on to consumers. This becomes a more influential consideration for building owners as water prices rise—it is not a matter of if but rather when and to what cost prices will rise as demand for water increases.

 Plumbing Fixtures The Energy Policy Act of 1992 (EPACT) set minimum water usage standards for typical plumbing fixtures based on the technologies then available (USC 1992). These values are used to calculate the baseline water consumption of a building when certifying a building. There are plumbing fixtures and equipment available now that are capable of significant reduction in water usage compared to the values used in 1992. Good guidance for the water consumption of current plumbing fixtures is available from such programs as WaterSense or ENERGY STAR® from the Environmental Protection Agency (EPA 2019c, 2019d). These information sources should be used to set the specifications for any highperformance building project and are also referenced for projects that are subject to codes that require higher efficiency systems, such as IgCC/189.1. A good comparison of the various water efficiency requirements has been published by the Alliance for Water Efficiency (2010). Plumbing fixture technology continues to advance toward lower water consumption without sacrificing the unit performance. Some of the more popular fixtures include waterless urinals, low-flush and multi-flush toilets, and low-flow showers, lavatories, and sinks. In addition to the fixture itself, control methods can also be used to reduce water use, such as sensors on lavatories to prohibit unnecessary runtime. Applicable state and local codes should be checked prior to design for the approved fixture lists; some codes have not approved the use of waterless urinal and low-flush toilet technologies.

 Appliances In projects such as hotels or in residential portions of commercial building developments, the specification of appliances such as clothes washers or dishwashers is sometimes the function of the original building design team. Again, the WaterSense or ENERGY STAR levels of water efficiency should be specified for all of these devices. These are also the basis for the requirements listed in the proposed Standard 191 and IgCC/189.1.

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 Water Heaters Many applications require the use of domestic hot water. Hot water can be generated in a number of different ways to serve a building. These different options can be broken into two primary categories: centralized and point-of-use. The water heaters themselves do not consumer more or less water, but the method of distribution can inherently result in using more water to serve the needs. A centralized water heater creates hot water that is then stored in a tank for delivery via the hot-water piping distribution system. The heating source could be electricity, natural gas, steam, or even waste heat from a process on site. The storage units could be located, in some cases, a long way from the fixture being served. A cold-water line must still be connected to the units, as well as an energy source (either electricity or gas) for heating the water,. As implied by the title, a point-of-use domestic hot-water heater provides smaller quantities of hot water at the point of use (at the sink or bathroom). There is some variation in point-of-use water heater types. Typically, the device may be instantaneous (e.g., located at a lavatory and producing hot water on demand—when the hot-water faucet flow comes on at the desired temperature), or it may have a small amount of storage capacity (usually 3 to 10 gal [11 to 38 L]) located in a nearby storage space. Point-of-use water heaters can save water by reducing the need to run water until hot water reaches the end point of use. These devices are applicable wherever hot-water is needed in small quantities, used relatively infrequently, and/or where it is excessively inconvenient or costly to run a hot-water line (with perhaps a recirculation line as well) from a central hot-water source. More on point-of-use hot water heaters can be found in the Additional Resources section at the end of this chapter.

7.6

BUILDING PROCESSES 

The third primary area where water is consumed within commercial buildings is in supporting the processes associated with the building. These include water used for HVAC systems, commercial food preparation, medical and laboratory services, pools and spas, and other special water features. In some situations these may be the dominant use of water within the facility. This section outlines the issues for consideration with each of these building processes.

 HVAC Many heating and cooling systems require the use of water to function. For commercial buildings, the primary water consumption for HVAC is through the use of cooling towers. The heat generated within the building or transmitted from the outdoors has to be rejected back outdoors. This is accomplished by running water between equipment inside the building producing the cooling, a water-cooled chiller, and the cooling tower outside. The cooling tower uses a water spray and fan to reject this building heat. This process consumes a lot of water because the principle of cooling, in this case, is based on the evaporative function of the water. For example, in an internal study on water conservation, one large university campus in the southeastern United States concluded that more than 20% of the campus water consumption was the result of cooling tower operation. This is a very common manner of providing cooling to large buildings, partly because water was previously not considered expensive and is readily available. There are alternative ways to cool a building currently being explored because of the importance of water conservation.

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 Commercial Food Services Water consumption can be high in buildings with food services such as restaurants, cafeterias, caterers, or food preparation kitchens, and thus careful attention must be given to the specifications of equipment used. Fortunately, concern about water consumption has led to products on the market that use water more efficiently, meeting criteria set by the ENERGY STAR program. Other innovations include handsfree faucet on-off controllers for sinks in food preparation and dish cleaning areas.

 Medical and Laboratory Facilities Similar to commercial food services, these facilities have specialized operations with the potential for significant water consumption. Also, similar to food services, innovations in these systems and pieces of equipment provide the design team options for water conservation, including equipment such as steam sterilizers, film processing, scrubbers, and water treatment systems. This is a specialized area, and IgCC/ 189.1 provides more information on the criteria that should be used in equipment specification for these facilities (ICC 2018a).

 Water Features, Pools, and Spas Ornamental fountains or other water features may also be part of the facility design. The aesthetic benefits of water features can be a compelling case for including them in the building project, but the design team must be mindful of applying methods for reducing the consumption of potable water for filling and makeup water (water that makes up for evaporation). Alternative sources of water should be investigated. These include rainwater, HVAC condensate, or foundation drain water. Care must be taken that the alternative source of water used does not pose a health hazard for the building occupants through potential exposure to the water feature, and thus not all types of alternative sources may be suitable for use in water features. The water feature should also include a meter for the makeup water as well as leak detection capable of shutting it off in the case that a leak is detected. For example, IgCC/189.1 specifies that this rate be 1.0 gal (3.8 L) per hour (ICC 2018a). For pools and spas, the specified design and equipment should include the following: • • •

Use of reusable filter cartridges Inclusion of a filter pressure gage (to determine when backwash is required) and a site glass on the backwash (to determine when backwash should be stopped). Swimming pool splash troughs, if used, should drain back into the pool.

7.7

ALTERNATIVE WATER SOURCES— RECLAIMED OR RECOVERED WATER REUSE 

Another way of improving a building’s overall water use footprint is to investigate alternative sources of water—that is, water that is not potable water from the local utility. From a typical initial cost evaluation of such systems, using reclaimed or recovered water may not often appear economically advantageous. However, in periods of drought, the actual value of a unit of water to the local society and economy may be worth much more than the rate currently charged by the local utility. Another choice may be to avoid the utility entirely and have a well into the water table. While this might be feasible, it still has some environmental footprint as it draws from natural water systems. There are many possible alternative sources of water that may be available with a building project. This section discusses these and the issues involved with the most common alternatives.

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 Uses for Alternative Water Supplies While a number of potential ways exist for how reclaimed water can be used in a high-performance building, each must be carefully considered and properly designed for. Not all options are possible or practical for any given building. More common methods include using reclaimed water for makeup water in cooling towers, toilet flushing, and landscape irrigation. Additional design considerations for each of these potential methods are discussed in the following subsections.

 Rainwater Rainwater harvesting is a simple technology that has been around for thousands of years. Harvested rainwater can be the sole source of water for a given use, or may augment other water sources. Systems can be as basic as a rain barrel under a downspout or as complex as a pumped and filtered greywater system that provides landscape irrigation, cooling tower makeup, and/or building waste conveyance. Systems are generally composed of five or fewer basic components: a catchment area, a means of conveyance from the catchment, storage (optional), water treatment (optional), and a conveyance system to the end use. The catchment area can be any impermeable surface from which rainwater can be harvested. Typically, this is the building roof, but paved areas (e.g., patios, entries, and parking lots) may also be considered. Roofing materials made of metal, clay, or concrete are preferable for roofs planned for rainwater harvesting compared to those with potential contaminants such as asphalt or those with lead-containing materials. Similarly, care should be given when considering a parking lot for catchment because of oils and residues that can be present. This collected water is routed via piping to a storage location or directly to the end use. This storage tank or cistern can be located above grade, buried outside the building, or placed on the lower levels of the building. In the case there is more rain water than planned, the storage tank should have an overflow device piped to a storm drain system. There is also the potential for less rainfall than expected in periods of drought; therefore, a potable water makeup line may be required. Depending on the catchment source and the end use, the level of water treatment will vary. For simple site irrigation, filtration can be achieved through a series of graded screens and paper filters. If the water is to be used in toilets or urinals, then an additional sand filter is appropriate to protect these fixtures. Parking lot catchments may require an oil separator. The local code authority will decide acceptable water standards for filtration and chemical polishing of this water may be required, rather than be a design choice.

 Greywater Systems Greywater is generally considered as being wastewater from lavatories, showers, bathtubs, and sinks that are not used for food preparation. Greywater is further distinguished from blackwater, which is wastewater from toilets and sinks that contains organic or toxic matter. Local health codes have regulations that specifically define the two kinds of waste water streams in their respective jurisdictions. Plumbing codes require that a colorant be added to greywater used within buildings, such as for toilet flushing, to help distinguish it as nonpotable water. Typically, for a commercial greywater system (e.g., for toilet flushing in a hotel), a means of short-term on-site storage, or a surge tank, is required. Greywater can only be held for a short period of time before it naturally becomes blackwater. Often some treatment of the greywater is done, such as a bleach solution or other means, to prolong storage time and minimize the potential for occupant exposure to unhealthy water. The surge tank is provided with an overflow to the blackwater waste system and a potable water makeup line for situations when the end-use need exceeds stored capacity.

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Distribution is accomplished via a pressurized piping system requiring pumps and some low level of filtration. Usually, there is a code requirement for the greywater system to be a supplemental system. Therefore, systems will still need to be connected to the municipal or localized well service. Careful consideration should be given before pursuing a greywater system. While a greywater system can be applied in just about any facility that has a nonpotable water demand and a usable waste stream, the additional piping and energy required to provide and operate such a system may outweigh the benefits. Such a system is best applied where the ratio of demand for nonpotable water to potable water is relatively high and consistent, as in restaurants, laundries, and hotels. Some facilities have a more reliable greywater volume than others. For example, a school might have substantially less greywater in the summer months or when classes are not in session. This may not be a problem if being used for flushing purpose, since it can be assumed that this water use would vary with occupancy. However, it would be detrimental if greywater was planned for use with landscape irrigation.

 HVAC Condensate If the cooling coil surface temperature is less than the dew point of the airstream passing by, water will condense on the cold cooling coils as air passes across. Water that condenses on the coils will collect and drop to the drain pan below. In conventional building systems, this water typically drains, unused, to the sewer system or other disposal method, but it can be worthwhile in some situations to capture and reuse it. HVAC condensate from commercial building scale air-handling units (AHUs) can be a source of good quality water if care is given in the maintenance of the air-handling systems (Glawe et al. 2016). One choice for use of this water is as part of the makeup water feed for a HVAC cooling tower, but in general collected condensate is a good source of relatively clean water that can be used in numerous applications. Condensate collection can be integrated with a rainwater collection system, a scheme sometimes referred to as rainwater plus. This usually involves a storage tank or cistern and can require considerably more expense and engineering than using the condensate in a cooling tower. Depending on the intended use, different amounts of further treatment may be required. In all cases, local building codes must be followed. Factors that determine whether condensate collection should be considered include climatic location and humidity; building type (particularly relating to the amount of outdoor air required); the size, number, and accessibility of air handlers that condition outdoor air; and location of potential uses for the condensate. Location determines both the potential to collect a significant amount of condensate and the value of the water to the local community. Condensate collection in new buildings is more easily done since it can be planned for with lower costs and fewer complications, but existing building retrofits present the highest savings potential as existing buildings comprise about 98% of the building stock. A major source of condensate water is from outdoor air brought in through outdoor air intakes for ventilation. Building or space occupancy type determines the amount of outdoor air required for health and safety of the occupants or to compensate for exhaust, and thus, the amount of moisture in the incoming air. A building or space that requires a lot of outdoor air on an ongoing basis (e.g., a laboratory) is an ideal candidate for condensate collection. Other obvious candidates include spaces with high occupancy densities or indoor water features. A method for estimating the amount of potential condensate that might be collected is given in the additional resources listed at the end of this chapter.

7.8

WATER CONSUMPTION MONITORING, MEASURING, AND MANAGEMENT 

The old adage that “you can’t manage what you don’t measure” holds true with both the flows of water and energy through building systems. That is why high-performance building rating systems and stan-

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dards have included methods to encourage (with a rating system) or require (with a standard) some level of monitoring and recording where water is used in the building.

 What to Monitor and How to Measure Most commercial buildings have one or more water meters installed by the local water utility to record how much has been used for billing purposes. This information only provides a gross level of detail, or the how much question. To effectively manage the question of how water is used, it is necessary to have additional monitoring or submetering devices installed. Note that this is different from the metering that might be done for billing residential units that are part of a commercial building development. The question is then, what does the building owner and operations team need to know? It is desirable to know how much water is being used by major building functions or equipment. These include items such as HVAC cooling towers, landscape irrigation, and other heavy users of process water. It is also desirable to know how much water is derived from alternative sources such as collected HVAC condensate. This information can be used for reporting purposes, tracking of return on investments, or for public relations releases. It is generally not necessary that the monitoring or submetering be done with utility-grade water meters, which can be fairly expensive. However, it is useful for the meters to be capable of communicating their information to a central recording station within the building. This allows for automatic recording of the water usage (or water production in case of an alternative source).

 Using Monitoring Data to Maximize Efficiency The level of detail needed to monitor data might differ with the type of water consumption. It is handy to have information on the makeup water flow to each cooling tower with the building, as that provides another method for leak monitoring and detection. This is where making the meters capable of communicating to a central monitoring station is useful; it provides for near-immediate notification if a leak has started, or if any unusual operational situation seems to be forming. Because the water usage data is sent to a central location, that information can be compiled to create a benchmark of building performance. Particularly in the initial years of operation, this benchmarking can be a point of reference in the future to detect problems or issues with the building operation.

7.9

PRESCRIPTIVE MEASURES VERSUS PERFORMANCE GOALS: ESTIMATING WATER CONSUMPTION 

The concept of prescriptive, as compared to performance-based, criteria in building standards is discussed in Chapter 2. Many of the criteria discussed in this chapter are prescriptive by nature, such as plumbing fixture selections that adhere to WaterSense or ENERGY STAR efficiency levels. Specifying the use of low-flow fixtures should result in water consumption savings associated with those specific devices, but consideration should be directed to the overall total water consumption of the building, not just how any one particular device functions. Similar thinking applies to the considerations for the energy efficiency of one piece of equipment as compared to the total overall energy consumption of the building. To judge the overall effect on total building performance, methods are needed to predict water overconsumption for a building given various scenarios for equipment and fixture specification. A discussion on a simplified method for doing this is contained in one of the additional resources for this chapter, and as part of one of the class exercises at the end of this chapter.

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7.10 CERTIFICATION SYSTEMS AND CODE REQUIREMENTS  This section provides a brief outline of specific provisions in the LEED certification system and IgCC/ 189.1 concerning water use and efficiency. These are included as samples of criteria any highperformance building should consider for inclusion in their design.

 The USGBC’s LEED Certification System The criteria for LEED (version 4) includes, for example: • •

•

A prerequisite for the recording of whole-building water usage and a commitment to share that information with the USGBC for at least five years A credit point for installing permanent meters that monitor at least 80% of the water usage for at least two of the following water subsystems: • Irrigation • Indoor plumbing and fixtures • Domestic hot water • Other process water In addition to the above subsystems, monitoring for boilers that are expected to use more than 100,000 gal (378,500 L) of water annually or have a combined heat input rate of 500,000 Btu/h (150 kW), and for any reclaimed water usage (USGBC 2019a)

 IgCC/189.1 The IgCC/189.1 includes requirements on outdoor water use for irrigation, indoor use for domestic purposes, for HVAC, food and medical processes, and for condensate collection from HVAC AHUs. For example, concerning the water use for outdoor irrigation, the IgCC includes a provision that a minimum of 60% of the improved landscape be planted in native or adapted plants, with the assumption that little or no supplemental irrigation would be needed to sustain those plants. In the area of building internal water use, the IgCC/189.1 focuses on ensuring that all internal water features meet a minimum level of high-performance and efficiency. This is defined as water usage rates that meet a minimum level of performance as defined in the EPA ENERGY STAR program or equivalent. Concerning HVAC systems, the IgCC/189.1 puts limits on the number of cycles of water through a cooling tower. It also requires condensate collection on AHUs above 5.5 tons (19 kW) of cooling capacity in humid regions (areas with a design wet-bulb temperature greater than 72°F [22°C]). There are also specific requirements for other process systems such as food preparation and medical facilities, the details of which are beyond the scope of this book. The final aspect to discuss with this code is the monitoring of water consumption in key systems above a given water usage threshold. This involves the installation of meters with data storage and retrieval capability on those systems and areas. For example, this applies to the cooling tower makeup flow for cooling towers with greater than 500 gpm (30 L/s) process flow rate. This roughly corresponds to roughly 200 tons (700 kW) of cooling capacity, and thus includes most cooling towers in commercial building operations. These standards also set threshold size before water consumption; monitoring is required for the landscape irrigation based on area irrigated, the alternative water sources that are used, for the process water uses, and for separately leased spaces or buildings on a project campus (ICC 2018a).

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Case Studies Consider the following examples of high-performance buildings that include significant water efficiency designs. These examples are not all mainstream (of yet) but represent the application of technologies that can be an important part of a water efficient future. Details on each can be found at www.ashrae.org/HPBSimplified. The Omega Institute for Holistic Studies This organization, situated on a 195-acre campus of over 100 buildings in New York state, implemented a system that processes wastewater on site and incorporated this system into their educational mission (Omega 2019). The treated wastewater is used for irrigation purposes and for other campus greywater systems, such as toilet flushing. More details on this installation are included in the report by Lesniewski (2011) at www.ashrae.org/HPBSimplified. Jeffrey Trail Middle School The Jeffrey Trail Middle School is a new school in the Irvine Unified School District (IUSD). The school was designed and constructed to meet the Collaborative for High-Performance Schools (CHPS) performance standards for exemplary energy and water conservation (NBI 2016). 2012 London Olympics The 2012 London Olympics set goals for water efficiency. The Olympic Development Authority determined that efficiency measures were the most cost-effective way to reduce overall water use for the Games (WRAP 2011).

Additional Resources for Further Study Several additional study and reference documents are available www.ashrae.org/HPBSimplified. For this chapter, this includes the following: • • • • •

Case Study: File name “Omega Institute—Completing the Circle” Case study: Jeffrey Trail Middle School https://newbuildings.org/resource/ultra-low-energy-school-case-study-jeffreytrail-middle-school/ (NBI 2016) Case Study: London 2012 Olympic Park www.wrap.org.uk/content/water-efficiency-case-study-london-2012-olympicpark-0 (WRAP 2011) Examples for a process to estimate the amount of condensate: • File name “Estimating the Amount of Condensate Collected” Example for a process to estimate total annual building water consumption: • File name “Computing Baseline Predicted Building Water Consumption”

at

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• • • •

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Additional resource: Onsite Non-Potable Water Reuse Practice Guide (William J. Worthen Foundation 2018) www.collaborativedesign.org/water-reuse-practice-guide Additional resource: File name “Quality of Condensate from Air-Handling Units” Additional resource: File name “Waterless Urinals” Additional resource: File name “Point-of-Use Water Heaters”

Application for a Future Career The design of the water consumption and water supply systems is more complicated for high-performance buildings compared with traditional designs. Newer technologies for water savings require more complicated analysis and design considerations to ensure that they will work properly and as intended. Unfortunately, some attempts at incorporating newer technology concepts for water savings and reuse have ended up with problems, often caused by lack of understanding of the technologies by the design engineer, installation contractor, or building operations team (or any combination thereof). The mechanical, electrical, and plumbing engineering firms that do highperformance building designs need people that understand these newer technologies, recognize when they would or would not be compatible with a given building situation, and can successfully design and oversee the construction and commissioning of these systems.

Discussion Topics, Exercises, Investigation Study Topics, and Assignments For Class Discussion: 1.

During periods of drought, many localities or jurisdictions implement restrictions on outdoor landscape and grounds irrigation (at least those using potable water). a. Are watering regulations a necessary restriction placed on businesses and residences or should municipalities instead rely on voluntary water use restrictions? b. If restrictions are deemed appropriate, would it be okay to use well water to irrigate landscaping at a business or home? c. If restrictions are deemed appropriate, are they better done using: i. Across the board restrictions setting maximum usage for businesses and residences? ii. Using a tiered pricing structure (higher cost per unit for larger water users)? iii. Alternatives that might work better, at least for your locality?

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5.

6.

d. If pricing were used as the mechanism for restricting potable water for irrigation use, how would you decide what level of water use to begin requiring increased water rates? What factors should be considered when a water utility determines their rate structure for water use? Should municipalities subsidize the cost of water for residential users? Should the cost of water be different for lower-income segments of the population? Does the general student body on this campus feel that water efficiency is important? Why or why not? In-Class Exercises:

1.

In groups of 3 or 4 and based on your observations and knowledge about the campus where this class meets suggest how the campus can develop a more efficient water strategy in each of the following areas: a. Water use for exterior landscaping, including athletic fields b. Internal building water use c. Process water use (includes HVAC, labs, food services, and so on)

4.

Estimate the full-time equivalent (FTE) occupancy level for either the building this class is located in or some other building on the campus. This might require you to use your best judgment in making estimations and determinations (as many professionals do in the real world). The FTE is a way of saying the overall average occupancy of a building is equivalent to N number of people on average. Then, based on that number and other assumptions on water usage, estimate the water consumption associated with this building. If getting accurate information on this building and occupancy patterns is beyond the scope of this class, then determine as a class the best estimate value to use that would give representative total water consumption estimates. For Further Investigation and Study:

1.

2.

3.

Some localities are implementing the process of using reclaimed or “recycled” water as input to their potable water supply chain (the “toilet to tap” concept). Research localities where this has been implemented and summarize their experience, lessons learned, and so on. Research the water efficiency measures and programs that have been implemented on your campus. Is there documentation of water savings resulting from these measures? What additional areas are being considered or are in the works? If not much information is available, or there is not a concerted water efficiency program in place, try to determine the reasons for that and any barriers that exist. What are the technical factors that determine the amount of condensate water that can be collected from HVAC unit cooling coils? Is this a viable option where your campus is located?

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4.

Study the water consumption associated with electricity generation associated with the following generation mechanisms (consumption in this case is defined in the broader sense of water that becomes unavailable for later use at this location): a. b. c. d. e.

5.

6.

7.

8.

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Hydroelectric dams Natural gas fueled steam generation Coal fueled steam generation Nuclear power plants Large-scale concentrating solar power facilities

What factors determine the amount of water use in cooling towers for chilledwater generation? What can be done to increase the efficiency in terms of water consumed? What are the potential negative consequences to consider and avoid when trying to reduce the amount consumed? What are the pros and cons of using water cooled chillers versus air cooled in terms of total societal water consumption (by societal water consumption it is meant not just water consumed at the site but also the water consumed to generate electricity to power the chiller). Find out the average cost of water in the locality where you currently live. Does that include the cost of sewage disposal or is that a separate fee? Are there different tiers or rate structures depending on the amount used? In your opinion, does this rate structure encourage or discourage efficiency in how a building designer and the later operator would think of water efficiency? Now select a city in a region with a very different precipitation pattern (i.e., if you live a dry region, select a city in a region that typically has plentiful rainfall or vice-versa; your instructor may provide some suggestions for this). Repeat the same investigation and analysis. Are there any patterns to note? Investigate the issues surrounding the adoption and implementation of waterless urinals in commercial buildings. Develop recommendations for this technology implementation on your campus (Should it be adopted? What barriers to implementation might exist on your campus?). More information on this technology is given in the Additional Resources section. Potential Design Projects:

1.

2.

Select an AHU on your campus (perhaps in the building where this class meets) and study how a condensate collection system could be added there. Use the regression equations provided by Lawrence et al. (2012) to predict the amount of condensate that could be collected from this unit. This will require you to estimate the amount of outdoor air (in ft3/m [L/s]) going into that unit and to scale the results based on the number of actual operating hours per year that this unit runs. What are the preferred option(s) for using the collected water? Prepare the design sketches for how the condensate would be collected and how it would be handled after collection. Determine the building(s) best suited for rainfall collection systems on your campus. Prepare an initial conceptual design sketch on how rainwater collection and reuse might be integrated with this building(s).

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8 Energy: Conversion, Distribution, and Utilization This is the first of two chapters focusing on the important topic of energy. This chapter discusses how energy is used within a building and opportunities to improve energy efficiency beyond that of a conventional building design. After the introductory reflection exercise, metrics used in measuring the amount of energy used in a building are discussed, followed by the various ways energy is consumed in a typical commercial building. This is followed with a discussion on how energy is converted and distributed within buildings, and finally this chapter discusses how the building as a whole should be considered for overall energy efficiency. Later in Chapters 14 and 16 we introduce topics that are on the cutting edge of the design and operation of the built environment, many of which involve new energy system innovations such as integrating smart buildings with the smart grid, for example.

8.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: • • • • • • • • • • •

Air-handling unit (AHU) Centralized versus decentralized HVAC systems Combined (cooling) heat and power systems (CHP or CCHP) Energy use intensity (EUI) Ground-source heat pump (GSHP) Plug loads Power use effectiveness (PUE) Thermal energy storage (TES) Variable-air-volume (VAV) systems Variable-frequency drives (VFD) Variable refrigerant flow (VRF) systems

•

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Reflection Exercise: Why is Energy Use an Important Part of a High-Performance Building? Energy Consumption by Market Sector To recognize the impact of energy use by buildings in typical developed countries, it is important to first understand the percentage of total energy consumption they use. Consider the following: • •

•

What would you guess to be the percentage of total energy consumed by residential and commercial buildings? Identify the percentage of energy used in a typical commercial building for each of the following major consumption categories: plug loads (energy used by equipment that is plugged into receptacles); lighting; heating, ventilation, and air-conditioning (HVAC); refrigeration; and water heating. Do you expect these percentages to change based on building type (office, restaurant, medical facility, retail store, and so on)? If so, in which category are percentages most likely to be influenced by building type?

For a number of decades in the United States, data has been compiled on the consumption by end-use sectors of the economy (residential, commercial, industrial, transportation) by the U.S. Energy Information Agency (EIA); this data is available online (EIA 2017). Figure 8.1 shows the changing amounts in energy consumption by each sector for the past 70 years.

Figure 8.1. Energy consumption by end-use sector in the United States. (EIA 2017)

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The Impacts of Energy Consumption Does the cost of energy for buildings (mainly electricity and natural gas) reflect the true cost to society? •

The concept of externalities comes from the field of economics. Externalities are costs (or benefits) that affect one party and are beyond that party’s control or choice. For example, a manufacturing operation that discharges pollutants into a river does not usually pay anything to do so (except maybe a permit fee and compliance verification)—these are externalities to that company. If these pollutants cause harm to someone downstream, those are externalities from that person’s perspective. What externalities exist with respect to energy consumption? Are environmental costs part of normal consideration when energy costs are determined?

•

Commentary Total energy consumption by the commercial and residential building sectors has been essentially constant since the beginning of this century, while energy consumption in the industry sector has actually declined. The only sector where energy consumption has steadily increased during these decades is in transportation. The decline in industrial energy consumption can largely be attributed to a decrease in the amount of goods manufactured as well as an evolution in manufacturing processes. The recent interest in high-performance buildings seems to have had a positive effect of keeping total energy consumption flat while the total number of buildings (both residential and commercial) has grown. Ignoring externalities can influence the decision-making process when determining things like building designs. The design and operational decisions for a high-performance building should try to factor these issues into the decision process.

8.2

HOW ENERGY IS USED IN COMMERCIAL BUILDINGS 

There are two basic categories of building energy use: (1) the building systems used for human comfort and safety such as HVAC or lighting and (2) process loads. Process loads can be defined as those that are in addition to the basic building systems and depend on the type of building, its occupancy, and its operation. Cooking equipment in a restaurant or the computers in an office building are considered process loads. Energy usage breakdown for an average commercial building is illustrated in Figure 8.2. Although this data is based on commercial buildings in the United States, similar trends exist in commercial buildings throughout all developed economies and in many developing countries as well. Notice that roughly 50% of total building energy consumption is used by computers, office equipment, and “all other uses.” This means the building design team has only partial control over how much energy will be used, and the rest is determined by the choices made by occupants.

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The rest of this chapter provides more detailed information on the primary systems and design decisions that would be part of a highperformance commercial building. First, the basic concepts in understanding how each of these systems operates will be introduced, followed by identification of methods that drive the design toward high-performance.

8.3 HVAC SYSTEMS  For there to be heating, cooling, lighting, and electric power throughout a building, the energy required by these functions must be distributed from one or more central points. This is usually accomplished through the flow of cold and hot water, air, steam, electrons (electricity), or refrigerants. There are a number of different approaches the building mechanical system design can take to accomplish these functions, so we next investigate the basic system concepts for HVAC system design.

Figure 8.2. Energy use breakdown in typical U.S. commercial buildings.

 Centralized versus Decentralized Systems

Temperature conditioning in a building can be provided by centralized or decentralized systems. (EIA 2019) For the context of this discussion, the concept of centralized or decentralized refers to where the heating or cooling effect is originally generated. In a centralized system, the heating and cooling is created by a limited number of systems that then distribute that “hot” or “cold” to various areas of the building. In HVAC terminology, a building zone is the portion of the building where temperature control is provided by a single thermostat. A zone could be a single room (such as a private office), a collection of rooms, or a subset of a larger area (such as a portion of a big-box retail store). This is the context when we use the word zone throughout this chapter and book. Larger buildings tend to have centralized systems because of their scale and complexity. One common example is where cold and hot water are generated at a central location (or limited centralized locations) and circulated to air-handling units (AHUs) to provide cooling (and possibly initial heating) to an air distribution system. A variation on this is to have the chilled and hot water circulated to fan coil units located within each zone; for example, in a hotel where a separate fan coil unit provides conditioning to each room. Alternatively, the chilled or hot water could be circulated to beams or panels in a ceiling or through radiant floor heating and cooling. Another example of a centralized system is with variable refrigerant flow (VRF) systems where refrigerant is circulated throughout the building to provide cooling or heating as necessary to separate terminal units in each zone. These are described in more detail below and in the Additional Resources provided for this chapter. In contrast, a decentralized system has distributed conditioning units that provide the heating or cooling generation in each individual zone of the building. Heating can be accomplished with natural gas com-

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bustion, electric resistance coils, or with heat pump within units at each zone. These zone-level units typically accomplish cooling by using a refrigeration cycle to directly cool the air.

 Cooling and Heating Systems Because HVAC systems are designed to maintain the room air temperature, there must be a mechanism in cooling mode to transfer heat from inside the building to the outdoors using some media that also serves as a source of that cooling. Ultimately, the room air must be cooled, and thus there must be some mechanism that delivers water, air, or a refrigerant at a lower temperature than the room air temperature. Sometimes, the outdoor air temperature is cool enough to provide this cooling function, so all that is needed is the equivalent of “opening the window” and bringing sufficient outdoor air in to provide cooling. This concept is called economizing or free cooling. When outdoor air temperatures are too warm or humid to directly use for conditioning, a mechanicalbased cooling system must be used. Cooling can either be provided by a refrigeration cycle to directly cool the air or indirectly through the production of chilled water. Figure 8.3 is a sketch of a typical chilled-water-based cooling system. Chilled water is circulated to individual air-handling or terminal units to condition the building zones. That chilled water can be generated by chillers in each building or, in the case of district energy systems, at a centralized plant that provides the cold water to each building in the district. A chiller is used to transfer heat from the chilled water to a cooling tower water loop or the ambient air heat sink. Most chillers employ a refrigeration cycle to do the heat transfer, although there are also absorption and adsorption chillers that will convert a heat source to provide the cooling for chilled water. The type of system shown in Figure 8.3 is a watercooled chiller that uses a separate water loop to transfer heat to the outdoors via a cooling tower. A cool-

Figure 8.3. Representative centralized cooling system using chilled water.

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ing tower merely provides a mechanism to allow the water to come in contact with the ambient air, thus cooling the water through heat exchange and evaporation. An air-cooled chiller is simpler in that the chiller condenser is cooled directly by ambient air passing across the condenser coils. In the case of a centralized HVAC system in a commercial building, zone heating is generally provided by hot-water or electric resistance coils within terminal units (or refrigerant from a VRF system). In the case of hot-water heating, a similar distribution system to that shown in Figure 8.3 might be used, with hot-water boilers used in the place of chillers to create and circulate through a hot-water distribution system. A decentralized system with individual AHUs that directly condition the air supplied for each zone may provide the heat using a natural gas furnace, electric resistance heating, or a heat pump. More details on cooling and heating systems and equipment are given in the Energy Conversion section that follows.

 Air Distribution and Ventilation Systems Air is distributed through a system of ductwork in a building powered by fans. A building can be conditioned with multiple small units containing heating and cooling coils and a fan at each zone (decentralized) or with a larger centralized AHU. Besides thermal conditioning for occupant comfort another reason for air distribution in buildings is to meet requirements for ventilation. Ventilation is outdoor air brought into a building to dilute indoor contaminants. The process for determining the amount of outdoor air needed is described in Chapter 10. Probably the most common type of air distribution system in commercial buildings is a recirculating air system. In this system, return air from the building zones is mixed with some fresh outdoor ventilation air, then filtered, temperature conditioned, and returned to the various zones in a building.

 HVAC Load Calculations Determination of the HVAC system heating and cooling loads for a building involves a large number of factors and is an important part of the overall design for a high-performance building. Heat and moisture transfer mechanisms are complicated and transient in nature and may be unpredictable; they involve factors such as outdoor air temperature and humidity; solar heat gains; human occupancy patterns, usage, and temperature set point preferences; the mass and thermal transmission characteristics of a building; heat generated by people, lighting, appliances, and so on; and construction quality, to name just a few. Rules of thumb in terms of the cooling and heating system capacity needed for a given building will help guide initial estimates, but the actual system equipment sizing needs a more detailed analysis that is often performed using sophisticated software packages and building energy modeling (BEM). A complication for HVAC load calculations is the fact that these involve transient processes. For example, solar energy absorbed by the building wall will take time to warm the building envelope and structure and will gradually be transferred to the building interior as the envelope warms. This time delay can be on the order of a few hours, therefore we cannot simply calculate the instantaneous heat gains or losses based on steady-state conditions and assume it is the actual cooling or heating load for that particular hour. For a high-performance building (or any building really), it is important to properly size the HVAC system. The HVAC equipment can be sized to match the worst-upon-worst case scenario in terms of weather conditions, occupancy, and so on. Alternatively, the HVAC designer can design for less than worst-case conditions, understanding that the worst-case scenario is unlikely to occur very frequently. Undersizing the cooling or heating capacity can result in thermal comfort issues within the space during worst-case conditions. Oversizing systems, however, is not the solution. An oversized system will likely undergo what is termed short-cycling—the heating or cooling generation equipment turns on and off

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more frequently. That can particularly be bad for a cooling system because insufficient moisture may be removed by the cooling coils, leading to humidity control problems in the building. Not only will the system not function correctly if oversized, but it will also be dimensionally larger, cost more, and be less energy efficient. The goals should always be to right size the system, which is just as much of an art as it is a science.

8.4

LIGHTING 

Lighting is another significant item for the total energy consumption in commercial buildings. About 10% of the total annual energy consumption in buildings is lighting, as shown in Figure 8.2. Lighting technology is rapidly transforming, as the cost and availability of the more efficient light-emitting diode (LED) technology is displacing more conventional fluorescent lamps. Like the HVAC system, lighting influences both indoor environmental quality as well as energy consumption in a building. Thus, good design of the lighting system can significantly contribute toward the building being recognized as high-performance. Lighting also adds to the heat gain of the building space, which has a positive effect when heating is needed but increases the cooling load during other times. The discussion that follows provides insight into the latest technologies available and practices in the market at the time of this publication. Given the rapid changes in lighting technology, there may be recent advancements that are not reflected here. The lighting discussion within this chapter is focused on interior lighting, as site lighting was already discussed in Chapter 6.

 High-Performance Lighting Design High-performance lighting design is a comprehensive concept that looks beyond just saving energy; lighting also plays an important role in building occupant comfort and productivity. Sufficient lighting needs to be provided to allow the occupants to function, and the total life-cycle impact of the lighting systems needs to be considered. High-performance lighting solutions achieve the following: •

• • •

Reduction in energy consumption and operating costs • Longer lamp life • Higher efficacy in creating and distributing light • Efficient lighting controls Safety and security in all parts of an operation High-quality indoor environment Reduced carbon footprint through conscientious selection and specification • Reduced use of hazardous materials • Use of recycled materials • Location of supplier/manufacturer (for reduced transportation impacts) • Packaging • Responsible disposal at end of life

 Energy-Efficient Lighting Design The lighting design profession is increasingly focused on providing high-quality visual environments using energy efficient strategies. Lighting technologies are now more efficient, and expectations for interior illuminance (measured in foot-candles [I-P] or lux [SI] at the task level) have evolved to lower light levels than before while still meeting the illuminance levels required for the activities in a given space. It is therefore now possible to design high-quality lighting at connected power levels that are much lower than even 10 to 20 years ago. Most energy codes and standards limit the lighting power density (LPD) as

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a manner of addressing consumption. The LPD is defined as the watts of power allocated for lighting per unit floor area in a building. In addition to limiting the lighting power use, some have restricted or outright banned lamps with low efficacies (lumen/watt ratio). For example, incandescent lamps that convert only one-tenth of their consumed energy to supply light have been banned in Europe and a phase-out implementation began in the United States as part of the 2007 Energy Independence and Security Act (EISA) (USC 2007). EISA technically does not ban incandescent lamps, but rather sets minimum efficiency levels for lamps that most incandescent lamps can not meet. Most energy codes generally have building LPD limits between 0.8 and 1.4 W/ft2 (8.5 and 15 W/m2), depending on the occupancy type of the space. All buildings can be efficiently and comfortably illuminated using carefully selected standard lighting equipment. Successful lighting systems with LPDs of 0.7 to 1.0 W/ft2 (8 to 11 W/m2) can be applied to most building types by following basic application design criteria set forth by the Illuminating Engineering Society (IES) and lighting manufacturers.

 Daylighting and Daylight Harvesting Most buildings are designed to have some type of natural light transmitted through windows and/or skylights. The majority of commercial, industrial, and institutional buildings have windows and, in some cases, skylights. From a basic lighting and energy efficiency perspective, it is generally better to have a building with more of its windows on the north or south side of a building, compared to the east or west. In the Northern hemisphere, windows on the north side let in diffuse daylight without the worry of too much additional solar heat gain that might add to a cooling load (this applies to south-facing windows in the Southern hemisphere). South-facing windows in the Northern hemisphere can be shaded from direct solar heat gain in the summer but still let in solar heat during winter (again, similar for north-facing windows in the Southern hemisphere). East- and west-facing windows are less desirable for commercial buildings because the sun will be lower in the sky when it is impinging on those building surfaces and can thus add to the solar heat load (although this heat may be desirable in winter heating conditions). From an energy perspective, the optimal use of daylight is to reduce the load on the electric lighting system by dimming or switching off luminaires (lighting fixtures) when natural light provides ample illuminance for the tasks performed in the space. It is important to note that the incoming light is only usable if it is controlled to reduce glare and illuminates a space in a way that is comfortable to the occupant (including thermal comfort). This process of reducing electric lighting using daylight is known as daylight harvesting. Figure 8.4 shows an example of good daylighting implementation. The prediction of daylight harvesting savings is a complicated process that involves a comprehensive understanding of the site, building orientation, weather conditions, materials, and system integration. There are added capital costs for daylight harvesting elements, such as lamps capable of dimming, dimming controls, and photoelectric sensors to monitor daylight levels. It is important to justify these costs by accurately predicting the potential energy savings of daylight harvesting techniques. However, when the challenges of daylighting are appropriately addressed, significant energy savings are possible. From a lighting design perspective, daylight can be treated similarly to any other light source, so it can be used to compose lighting design solutions that take illuminance, luminance, contrast, color rendition, and other lighting design elements into consideration. However, the lighting designer is challenged by the fact that the light source varies daily and throughout the year. The designer can use blinds, shades, curtains, moveable shutters, light shelves, light conveyors, and other mechanical forms of attenuation and shielding to control daylight. It is possible to simulate the performance of daylight with the use of software models to determine the amount and, to a certain extent, the quality of available daylight under varying conditions of season, time

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Figure 8.4. Example of good use of daylight harvesting. Image courtesy of NREL

of day, and weather. This analysis can be time consuming and requires an experienced professional, but many buildings can benefit tremendously from the incorporation of some type of daylighting. Additional detailed discussion on topics associated with daylighting and lighting controls is given in the resource document “Daylighting and Lighting Controls” available at www.ashrae.org/HPBSimplified.

8.5

PLUG LOADS 

Plug loads represent the energy used by devices or machinery that are temporarily connected to the building’s electrical supply (hence the term plug). These connected loads have grown significantly in the past several decades as a result of increased dependence on computers and other electronic devices in the overall functioning of buildings. These loads are generally included as part of the computing, office equipment, and “other” categories, which together make up 20% of a typical commercial building’s energy consumption (although not all of that is what we would call plug loads). The decreased energy consumption for major systems such as HVAC and lighting in a high-performance building means that the plug loads have an increasing level of importance in overall energy consumption.

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The first step to address the plug load energy is to select equipment, when possible, that is high efficiency. This includes equipment that is ENERGY STAR® rated or equivalent. However, in most cases, the building design team has limited influence on the amount and what type of equipment is to be installed later. The design of a high-performance building should therefore include measures that allow monitoring of the plug load energy use and for providing that information to the building operations management (and perhaps the building occupants as well). The design should also include the ability for occupancy sensor control that turns off equipment when not in use or the power to receptacles in spaces that are not occupied.

8.6

DATA CENTERS 

The operation of data centers and servers is a rapidly growing area of energy consumption, using about 3% of total electricity worldwide. The design and operation of large-scale, dedicated data centers are specialized areas of expertise and beyond the scope of this book. However, many commercial buildings have their own data center(s) to manage the information technology (IT) needs. The basic metric used to evaluate the efficiency of a data center is Power Use Effectiveness (PUE), the ratio of the total energy used to run the data center compared to that used just for operation of the IT equipment. Well designed and operated data centers are now operating with PUEs in the range of 1.10, although this metric fails to compensate for factors such as differences in climate. ANSI/ASHRAE Standard 90.4, Energy Standard for Data Centers (ASHRAE 2016a) (or equivalent local standards or guidelines, such as EN 50600-X in Europe) should be used as the basis for the data center system design. Emphasis should be placed on overall system operation and efficiency as opposed to individual equipment specifications.

8.7

OTHER SYSTEMS 

Depending on the type and scale of a building, other systems will also contribute meaningfully to the building’s overall energy consumption. Two common systems are covered in this category: people moving (such as elevators and escalators) and commercial-scale cooking (as in restaurant or cafeteria).

 Elevators and Escalators The design and operation of elevators and escalators is now being covered as part of the regulated loads in commercial building energy codes. Elevators and escalators can consume in the range of 2% to 5% of the total energy in a typical commercial building (Sachs et al. 2015). There are two aspects of energy use that need to be considered for these systems: first is the overall efficiency in providing the mechanical movement and second is how the systems are operated when not in use (standby mode). Recent technology advances provide options for efficient movement as well as the potential for regeneration of energy. Regeneration involves the recovery of energy expended to raise the equipment, similar to hybrid cars where the braking action is used to generate power to recharge the electrical batteries. Regeneration can be done via electricity or hydraulic power as an individual cab is lowered in an elevator, converting the potential energy contained in elevation to stored electricity or hydraulic pressure. Efficient use of elevator cars or cabs can also be aided using smart control concepts. This control may be based on artificial intelligence or other predictive controls to schedule the placement and routes for the cars. Other concepts include systems where the passenger indicates at a central point in the main lobby to which floor they wish to go, and the control system schedules the cars’ operation accordingly and asks that the rider get in a specified elevator car.

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Many elevators and escalators move people during a good portion of time during the day, and thus offer energy savings potential. This can be accomplished by shutting off elevator cab lighting and ventilation when not in use or using motion sensors to operate escalators only as needed.

 Cooking Energy is used in a number of ways in commercial cooking operations. This includes the storage of food (refrigeration and freezing), food preparation (fryers, grills, steam cookers, ovens, and so on), ventilation and exhaust, holding of food in hot cabinets or warming stations, and cleanup. Energy savings are possible through the specification, scheduling, and operation of energy-efficient equipment. A true high-performance building with commercial cooking facilities must start with high-performance equipment, such as refrigeration and freezing appliances and kitchen exhaust hoods. This equipment should comply with the ENERGY STAR criteria for commercial refrigeration and freezers and commercial ice machines (EPA 2019d). The minimum criteria for kitchen exhaust systems has recently increased in stringency. These criteria are now commonly expressed in terms of a maximum allowable exhaust flow rate per linear length of the capture hood. The amount and control of makeup air (air used to compensate for the exhaust) to the kitchen is a vital part in achieving high performance. When possible, a high percentage of the makeup air to the kitchen should be transfer air, or air that is coming from other portions of the building. This saves energy compared to bringing in and conditioning additional outdoor air.

8.8

ENERGY CONVERSION 

This section provides a brief overview of the mechanisms where energy is converted in form for use within a building, in particular for heating, cooling, and ventilation purposes via HVAC systems.

 Heating Systems The seasonal efficiency of heating plant equipment (e.g., boilers, furnaces, and heat pump systems) has improved considerably during the last several decades. However, designers should verify equipment manufacturers’ claims by reviewing documented data of this equipment to ensure the efficiency ratings are accurate. In general, heating is provided through the direct combustion of a fuel source, the direct use of electrical resistance heating, or through electrically powered heat pump systems. Combustion-Based Heating. The main distinctions of combustion-based heating systems are in the fuel source (fossil fuel, biomass, or other combustible materials), and whether the heat is a byproduct of other use, such as in a combined heat and power (CHP) system or if the heat generation is dedicated for the supply of heat to the building systems alone. CHP systems are discussed further in Chapter 9, but these systems use a fuel source to first generate electricity and then use the waste heat from that process for other means, such as building heating. A common method to provide heat within a building is to use a boiler to generate steam or hot water and then distribute that hot fluid through the building. The flue gas of any boiler usually contains carbon dioxide, nitrous oxides, and water vapor with a dewpoint temperature of about 138°F to 140°F (58.8°C to 60°C). Any lower boiler return water temperature may result in water vapor condensation in the exhaust (and subsequently corrosion). Conventional boilers avoid this problem by limiting return water temperatures and keeping the flue temperature hot enough to avoid condensation. Condensing boilers, on the other hand, allow for extracting additional heat from the flue gas. The flue gas temperatures may fall low enough to have condensation occur, but they are designed to handle the corrosive nature of condensing water vapor.

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Refrigeration-Cycle-Based Heating. It is possible to transfer thermal energy (heat) from a source at a cooler temperature to a heat sink at a higher temperature. Doing so for heating requires the use of a refrigeration cycle in a heat pump. For the purpose of providing heat to a building, this cycle transfers heat from a source at a lower temperature (say, the outdoors in winter or the ground in a groundsource heat pump [GSHP]) to a warmer temperature (the building interior). It is beyond the scope of this book to go into too much detail on the refrigeration thermodynamic cycle, but suffice it to say that energy (most often electrical energy) is used to power the refrigFigure 8.5. Simple illustration of the operation eration cycle machinery that uses of a refrigeration cycle. refrigerant to absorb heat at a low temperature (and low refrigerant pressure) and discharge that heat energy at a higher temperature (and higher refrigerant pressure). The basics of a refrigeration cycle can be found in any thermodynamics course textbook, but a simple illustration is shown in Figure 8.5. For refrigeration-based heating, the cycle takes thermal energy from the colder heat source fluid (outdoor air or the ground) and transfers it to the heating medium (directly to the building air or to water for heating the building elsewhere).

 Cooling Systems The mechanisms to provide cooling within a building generally are more complicated than for heating, because they often require the transfer of thermal energy from the cooler indoor building space to a warmer outdoor ambient. Thus, it is not as simple as burning a fuel or plugging in to the electrical circuit to gain the cooling effect. The explosive growth in the demand for comfort cooling in commercial buildings during the past half century has led to a rapid increase in demand for energy consumption globally. Thus, this is a very important topic in the development of high-performance buildings worldwide. Figure 8.5 illustrates the basics of a refrigeration cycle to provide cooling. Chilled-Water Systems. Chilled-water plants are most often used in medium to large facilities. Their primary benefit involves higher efficiency, especially at warm ambient temperatures, and reduced maintenance costs, plus redundant capacity when compared to decentralized systems. Chilled-water systems are generally classified by their heat sink, such as ambient air in air-cooled chillers, cooling towers in water-cooled systems, or the ground in a geothermal-based system. (See also Figure 8.3.) A chilled-water plant generally consists of the following elements: • •

Chillers to generate the chilled water (more discussion on chillers follows) Chilled-water pumps

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Condenser water pumps (for water-cooled systems) Cooling towers or a below-ground piping/well network for geothermal-based water-cooled systems, or air-cooled condensers, Associated piping, connections, valves, and controls Later sections discuss the various system types for generating chilled water.

Refrigeration-Cycle-Based Chillers. The most common method for providing cooling is through the use of a refrigeration cycle. More details on such a system can be found in any thermodynamics textbook or in the online resources listed at the end of this chapter. Referring to Figure 8.5, refrigeration cycle cooling will remove thermal energy from the cooling media and transfer that heat to a higher temperature heat sink (ambient air or cooling tower condenser water) as the refrigerant condenses. Cooling is provided directly by the refrigerant to the building air or indirectly to another energy transfer medium such as chilled water. Absorption Chillers. Another chiller type is an absorption chiller, which uses a heat source such as steam, hot exhaust gases, or waste heat sources such as those from a combined cooling, heat, and power (CCHP) plant. In an absorption chiller, a low-pressure absorption fluid is evaporated to create chilled water. This absorption working fluid is regenerated using the heat source. A common working fluid used in these chiller types is a lithium or potassium bromide solution. These are complex cycles beyond the scope of this book. Adsorption Chillers. A few manufacturers market this alternative chiller type that also can use waste heat or heat from a solar thermal system. Adsorption chillers use a solid material instead of a the liquid used in an absorption chiller. One positive aspect of this chiller type is that they use a nonpolluting refrigerant: water. They are fairly simple in their mechanical construction and operation. However, their overall thermodynamic efficiency is low compared to a conventional refrigerant chiller, but this is may be acceptable as they are designed to run off a waste or renewable energy source.

 Final Notes on Specialized Equipment Heat Pumps. A heat pump is another means of generating cooling and heating using the same piece of equipment. This will be done with refrigeration-cycle-based equipment; the external source/sink of heat could be the ambient air, the ground, or nearby large bodies of water such as a lake or ocean. An array of heat pumps distributed throughout the building are usually used for large-sized projects (i.e., they are not part of a central plant). Buildings that have consistent demands for both chilled and hot water, such as hospitals, are good candidates to use a larger heat pump as a central plant, and in these situations could be designed to simply transfer heat from the systems or portions needing cooling to those needing heat. Thermal Energy Storage (TES). TES in and of itself is not a method to generate cooling, but is rather a technique encouraged by electricity pricing schedules where the off-peak rate is considerably lower than the on-peak rate. Cooling in the form of chilled water or ice is generated during off-peak hours and stored for use during on-peak hours. Although not refrigeration equipment per se, this technique can usually reduce the size of refrigeration equipment or eliminate the need to add a chiller to an existing plant. TES may also be used for heating systems in some situations and locations. The characteristics, merits, and cost factors of TES for cooling, as well as numerous reference sources can be found at www.ashrae.org/HPBSimplified.

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8.9

ENERGY DELIVERY AND DISTRIBUTION 

 Distribution Methods Ducts, pipes, and wires are used to move energy media (air, water/refrigerants, or electrons). Proper sizing of these distribution mechanisms is a balancing act between energy use, energy cost, and material first cost. Space is commonly at a premium in building design; therefore, there are advantages to distributing as much energy as possible through a more efficient carrier. Wires (electricity) have the capacity for carrying the most energy by unit volume, followed by pipes (hydronics), in turn followed by ducts (air). Although space conservation and coordination is important, it is not the only criteria to be accounted for. A designer must consider that the different energy-carrying media have different characteristics and capabilities in terms of meeting the requirements of the spaces served, as well as the first and operational costs associated with each media. This section provides a brief discussion on the issues involved with the different energy distribution methods and mechanisms.

 Wires—Electric Delivery Systems Not much needs to be said about this method for the delivery of the invaluable energy source of electricity. Energy is delivered via the flow of electrons through the transmission and distribution electric grid to a building and to the point of use by the building's own wiring network. Thus, in terms of space for the energy delivered, wires are a very compact way to deliver energy compared to the other methods discussed in this section.

 Pipes—Hydronic Energy Delivery Systems Hydronic systems consist of those that produce heat and cooling using water. This water can be in the form of hot water, chilled water, or steam. As previously mentioned, a hydronic system can transmit significant amounts of energy in a small cross-sectional area, especially when compared to an air system. Using common temperature and design strategies, the cooling energy that requires an 18 × 18 in. (45 × 45 cm) duct could be transmitted in a 1 in. (2.5 cm) chilled-water pipe. This saved space is an important advantage, but an even more influential factor is the reduced pumping power required to move this water compared to the fan energy required to move an equivalent capacity of air. Chilled-water systems distribute cold, chilled water to terminal cooling coils to provide conditioned air dehumidification and cooling or the process cooling. They can also serve cooling panels in occupied spaces. This chilled water is produced by a centrally located chiller and pumped through units/coils distributed throughout the facility. In terms of high-performance building design, one of the main factors for increased efficiency and performance is in the selection and design temperature difference ( T) between the supply and return temperatures. This decision is typically determined based on the chiller selection and the performance criteria of the units/coils. Similarly, distributing hot water throughout the building is generally the most efficient heating energy distribution method. Most HVAC hot-water heating systems will operate at temperatures of 250°F (121°C) and below. This hot water is used to heat air in air handling or fan coil units, or in radiant heating through floors, registers, or ceiling panels. Generating steam requires heating water above its boiling point. Steam is considered an inefficient way to transport heating energy for space and domestic water heating because temperatures as high as the steam temperatures are not needed for these applications. Plus, additional safety measures (such as higher insulation of the piping) are needed. Steam is primarily used in two applications—where steam is needed for other processes within the building (i.e., sterilization or laundry) or when distribution distances are

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long (i.e., from a central plant on a large campus). Steam is rarely routed to the occupied space level within a building but is instead used to heat hot water for distribution. Steam is different from other hydronic systems in that it does not require a supply distribution pump. Steam moves through a supply piping system because of its pressure. As steam moves through the piping or is used for heating, it cools and returns back to hot water called condensate. The condensate then is returned back to the boiler, preferably via gravity to avoid the expense and energy associated with operating another pump, although this is not always possible.

 Ducts—Air Delivery Systems Using air as a means of energy distribution is almost universal in buildings, especially as a means of providing distributed cooling to spaces that need it. A key characteristic that makes air so widely used is its importance in maintaining good indoor air quality (IAQ). Thus, air distribution systems are not only a means for energy distribution, they also serve the essential role of providing ventilation. It is important to understand that properly distributing air to heat and cool spaces in a building is less efficient from an energy usage perspective than using hydronic distribution. Air distribution systems are often challenging to design because, for the energy carried per cross-sectional area, they take up the most space in a ceiling cavity and are frequent causes of space conflicts among disciplines (i.e., structural, plumbing, heating/ cooling pipes, lighting, and so on). Another tricky aspect of air system design is that there are temperature limitations on supply air. Lowtemperature air supply systems providing cooling from ceiling supply diffusers offer many advantages, but an especially critical design aspect is avoiding occupant discomfort at the supply air/occupant interface. If not carefully designed, the space temperature may be maintained, but the space in some places may feel drafty and uncomfortable to the occupant. Heating delivery air temperatures are also very important when introduced to the space from the ceiling (as is commonly done in commercial buildings) because of the potential for stratification. When air is supplied much warmer than the room air (greater than about 20°F [10°C] above the room thermostat set point), that hot air remains near the ceiling because of its buoyancy effects, and therefore the goal of conditioning the occupant is not effectively achieved.

 Refrigerant Distribution One more energy distribution method is worth a brief mention. VRF systems have been used in Asia and Europe since the late 1980s. The basic concept is to circulate warm or cool refrigerant through the building and use it to directly condition the building zones. In addition to the refrigerant delivery piping, air distribution ducting is needed as well to provide the ventilation air.

 Efficiency in Energy Distribution: Power, Flow, and Pressure If heating and cooling could be produced exactly where it is needed throughout a building, overall system efficiency would increase—there would be no additional energy used to move conditioned water or air. In addition, the energy loss potential due to heat gain or loss during distribution is eliminated. For acoustic, aesthetic, logistic, and a variety of other reasons, this ideal is seldom realized. Therefore, fans and pumps are used to move energy in the form of water and air. Throughout this process, the goal is to minimize system energy consumption. Understanding how fan and pump power change with flow and pressure is imperative to optimization (balancing cost between energy and operation). Energy savings can be realized from reducing the resistance to flow of electricity or fluid attributed to the friction imposed by the conduit: the wire, the pipe, or the duct. It takes significantly more energy to move the same amount of electricity, water, or air through a small wire, pipe, or duct compared to a large one. This is simply a function of a higher resistance in smaller wires compared to larger ones (for electric-

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ity) or the higher flow velocity and thus larger pressure drop needed to move the same amount of fluid through ducts or pipes (for air or water). To reduce system resistance, sizes should be maximized within the space allowed.

 Efficiency in Energy Distribution: Variable-Speed Drives In most fluid moving systems for HVAC applications (hydronic or air), there is not a consistent heating and cooling load year-round; changing climatic conditions due to changing seasons or time of day, fluctuating occupancy numbers, varying equipment operating schedules, and so on are all factors that affect loads. These shifting loads result in heating and cooling systems that do not operate at full capacity all the time. Therefore, varying the flow provided with variable-speed pumps or fans to match the actual load at that point in time can be a significant source of energy savings. Variable speed of the prime mover (fan or pump) is achieved by a variable-frequency drive (VFD) that adjusts the motor input electric current frequency. The motor turns at a speed proportional to the input frequency. For example, a motor designed for a nominal 60 Hz current (the frequency used in the United States) that is provided with electrical current at 48 Hz will rotate at 80% of its design rotational speed. Because the volumetric flow provided by a pump or fan is directly proportional to the rotating speed of that device, a pump or fan rotating at 80% speed will provide 80% of the fluid flow than it would at its maximum rotational speed. The pressure drop of a fluid moving through a pipe or duct is proportional to the square of the fluid velocity. For a typical piping or ducting system, a simplifying assumption can therefore be made: reducing the fluid flowing to X % of the maximum flow will reduce the overall resistance or pressure drop through the system to X2 when compared to what is required at the maximum rotational speed of the pump or fan. The pump or fan power is proportional to the fluid flow rate times the pressure input to the fluid. Combining all this, the overall pumping or fan power is proportional to the cube of the pump or fan rotational speed, as the flow rate is linearly proportional to the rotating speed times the pressure input required, which is itself proportional to the square of the flow rate. Therefore, for the example where a fan or pump is controlled to rotate at 80% of its maximum design speed, the power input to that device would be as follows: Power = Mass flow × Force (Pressure drop) = 0.8 × 0.82 = 0.83 = 0.512 Thus, a fan or pump rotating at 80% of full speed would require approximately 51% of the power compared to that needed for the device at full speed.

8.10 APPLICATION TO OVERALL BUILDING DESIGN  The focus up to this point has been on individual technologies or equipment and their contribution to overall building energy efficiency. However, what is truly important is how all these parts and systems interact together to produce a building that operates at the highest overall performance while still providing the appropriate services and environment for the people inside. This requires the integration of all these parts into a smoothly functioning system, much like it requires the integration of all the parts of an aircraft to make it fly. Doing this right takes insight into building operations and design, keeping up-to-date on the latest technologies, and having the project management and business acumen to pull it all together. BEM is one potential tool in the process; it helps to screen potential design concepts and technologies to evaluate their overall benefit and cost effectiveness using physics-based software tools to analyze the detailed energy use within a building throughout the year on an hourly basis. These software tools use detailed inputs from the building geometry, construction materials, systems configuration and type (HVAC, lighting, and so on), occupancy

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patterns, and local climatic patterns in this process. Besides energy consumption, BEM tools can provide information on system interactions and evaluate and compare different design decisions. These models can be used for a number of different purposes. Different aspects of the architectural design can be compared and evaluated, such as the energy savings benefits of incorporating a higherefficiency window. The energy savings can be used to determine the costs and benefits to help inform decision-makers. Similar evaluations can be made with HVAC system trade-offs for efficiency, among other things. These evaluations can be done fairly simply, at relatively low cost, and assist the design team in optimizing the performance gains for the cost of implementing those technologies. Building energy models are also used to verify energy performance for applications such as green building certifications.

8.11 BUILDING CERTIFICATION PROGRAMS AND CODE REQUIREMENTS  As may be expected, a significant percentage of requirements in high-performance building certification systems and codes/standards are focused on energy efficiency. This section provides a brief outline of how building certification programs (using LEED as an example) and the International Green Construction Code (IgCC/189.1) address the issue of energy efficiency.

 Building Certification Programs The Leadership in Energy and Environmental Design (LEED) certification system section that focuses on energy and atmosphere consists of a total of 33 credit points, of which 28 are focused on the efficient use of energy and monitoring that energy use. The largest of these is the Optimize Energy Performance credit, which allows up to 18 credit points for demonstrating the reduction in energy consumption compared to a standard baseline design. LEED focuses on the predicted overall performance level of the building, which differs from the approach taken by IgCC/189.1 and outlined below. Other credits include a focus on energy metering (for use in monitoring of performance during operation) and designing the building systems for participation in demand response (DR) programs that allow for electrical load shedding or shifting to nonpeak demand time periods (USGBC 2019a).

 IgCC/189.1 This high-performance building code contains a number of requirements for improvements in the building and systems designs that will improve the energy performance beyond what would be achieved by only following the minimum energy code. The scope of systems included covers all aspects of the building systems, such as HVAC, lighting, plug loads, and so on. IgCC/189.1 addresses these by specific prescriptive requirements that outline how higher efficiency would be achieved compared to the minimum energy code. There also is an alternative performance-based approach that focuses on a predicted overall level of energy performance, similar to the LEED program. The code also includes items such as the installation of energy monitoring systems (ICC 2018a).

8.12 SUMMARY  In summary, this chapter provides an overview of the various uses of energy within a building, methods for better efficiency, and how energy is moved within the building. The next chapter builds on this to consider how energy is generated (or converted) for use by buildings and the built environment.

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Case Studies 1.

Review the High-Performance Buildings case study “From Darkness to Light: Engaging Employees to Save” from the Summer 2015 issue (Bowman and Nagle 2015). • List the three key energy-efficiency-related items that this building and the design/implementation team did well. Were there any additional cost implications for the design and construction? • Are there any areas that could have been done better, or what seems to be lacking this design? State your reasoning. 2. The National Renewable Energy Laboratory in Golden, CO conducts research concerning building energy efficiency (among a number of other topical areas). An excellent case study is their Research Support Facility complex. These buildings are designed to demonstrate methods to achieve a net zero energy facility that is cost-competitive and replicable for other projects. (A net zero energy facility is one that generates as much energy as it consumes on an annual basis.) Videos and an article in High-Performance Buildings magazine on this project are included at www.ashrae.org/HPBSimplified (NREL 2010, 2015; Hootman et al. 2012). • List the key energy-efficiency-related items that this building and the design/ implementation team did well, and what additional cost implications there were for the design and construction (if any). • How was this organization able to implement the amount of photovoltaic (PV) energy resources sufficient to make it net zero?

Additional Resources for Further Study Several additional study and reference documents are available www.ashrae.org/HPBSimplified. For this chapter, this includes the following files: • • • • • • • • •

at

Double-Effect Absorption Chillers CHP or CCHP Systems Daylighting and Lighting Controls District Energy Systems Ground-Source Heat Pumps (GSHPs) Thermal Energy Storage (TES) for Cooling Variable-Speed Pumps and Fans Variable Refrigerant Flow (VRF) Systems Net Zero Blueprint (NREL Research Support Facility Case Study) (Hootman et al. 2012)

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Application for a Future Career Ever since the initial energy crises in the 1970s, people have made careers and even an entire industry out of improving building energy efficiency for both new and existing buildings, such as in conducting building energy auditing and energy performance contracts, energy modeling, and commissioning. These tend to be service-type jobs that require skills in engineering, economic analysis, construction, and legal issues. But there is also a demand for people that can conceptualize and design new highperformance equipment and systems required to achieve desired high-performance building design. Building energy auditing is a process that assesses a building’s energy performance compared to standard performance metrics. The auditing process may also involve the preparation of proposed energy efficiency measures that would improve the overall energy performance of the building. These energy efficiency measures may be implemented directly by the building owner and operations team or by the energy auditing firm through an energy performance contract. In an energy performance contract, the contracting firm determines and analyzes the energy efficiency measures in sufficient detail such that they can guarantee energy cost savings of a certain level. The firm will implement and pay for the efficiency measures, using the energy savings to pay for their cost (and their anticipated profit). One good resource to learn more about building energy auditing is in A Guide to Energy Audits, a report published by the U.S. Department of Energy (DOE) (Baechler et al. 2011). As you gain experience in this area, you may consider earning certification such as the Building Energy Assessment Professional (BEAP) program. The industry also needs people with skills in BEM. BEM requires a detail-oriented person who can interpret the modeling results as a valuable contribution to the building design process. The results can be used to determine which high-performance options have the greatest impact and potential return on initial investment. Building modeling is also a key step in many different building certification processes.

Discussion Topics, Exercises, Investigation Study Topics, and Assignments For Class Discussion: 1. 2. 3.

What is the real difference between a kW (kilowatt) and a kWh (kilowatt-hour)? Can both of these be measured? Describe how knowledge of both of these is important to the building owner. Does the cost of energy for buildings (electricity or natural gas for the most part) reflect the true cost to society? If not, what is not accounted for and why do you think it is left out? What are the impediments (technical, economic, regulatory, and so on) to implementing CCHP on a typical university campus? How could these be overcome?

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4. 5.

6. 7. 8.

What do you think this university’s reputation is concerning energy efficiency? Does this match what is expected at the local, state, and regional levels? How could plug load management be effectively implemented on this campus? Are there measures already in place and, if so, what are your opinions of how well they work? What types of measures would you support or not support? How important do you think energy efficiency is to students on this campus? Do students actively help or hinder energy efficiency measures that may be in place? What are the factors and issues involved with implementation of district energy delivery on this campus? Is district energy already in place on this campus? What are the reasons why or why not? Is daylighting control possible for the room where this class meets? Are there other locations in this building or on this campus where daylighting should be considered or is already being implemented? If already in place, how is this perceived by the occupants? If not, but some potential locations are identified, discuss what issues would need to be addressed as part of the implementation. In-Class Exercises:

1.

Review the additional resource document on GSHPs (Additional Resource on Ground Source Heat Pump.docx). a. Based on this initial review, do you think a GSHP should be considered a renewable energy resource? Why or why not? b. Make a list of two key reasons why a GSHP should be considered a renewable energy source. Next, list two key reasons why not. The reasons could be based on technological, economic, or environmental criteria. c. Select a partner in the class and each of you take one of the positions (either yes or no that GSHP is a renewable energy source). Spend 2 to 3 minutes each trying to convince the other person to agree with your position.

2.

Make a survey of the building where this class meets. a. Compile a list of the various rooms and note the major energyconsuming items. b. Are there obvious energy efficiency measures being implemented? c. Identify any obvious energy-wasting items (such as lights left on with no one in the room). d. Make a list of additional energy efficiency measures that might be considered for this building and your classroom.

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3.

4.

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Several questions follow regarding the computation of energy use intensity (EUI) and energy cost index (ECI). The EUI is expressed in terms of thousands of Btus per square foot of floor area per year (kWh per square meter per year). The ECI expresses these values in terms of energy cost per floor area. (See Chapter 1 for more details on EUI.) a. What is the fuel efficiency of your vehicle in miles per gallon (liters/km)? b. Make an estimate of the EUI of the apartment or house where you currently live. c. Why is it that people often know the performance of their vehicles but, when considering an item that is a larger investment, such as where we live (cost of rent or mortgage plus monthly utilities), we do not know this value? d. How could the conversation be changed so that awareness of building energy use and performance becomes a higher priority? e. Using information on the total energy consumption of the building where this class meets (or some other building on the campus that you can get information on), compute the EUI for the building. If that information is not available, use data from a typical engineering classroom/laboratory building given in Table 8.1. f. Using information on local or campus energy costs (or reasonable assumptions), compute the energy cost index (ECI) for the building. g. Go online to the following energy performance websites and compare the results to other similar buildings in this climate: • EPA Portfolio Manager— https://portfoliomanager.energystar.gov (EPA 2019e) • LBNL Building Performance Database— https://bpd.lbl.gov/ (LBNL 2019) One ton of cooling is the equivalent of 12,000 Btu/h (3.52 kW) of energy delivery. Using simplifying assumptions and standard rules of thumb: a. Compare the volumetric flow rate needed to deliver 50 tons of cooling within a building using air versus chilled water. For this exercise, assume that the difference between the chilled-water supply and return temperature both from and to the chiller is 10°F (5.6°C) (the traditional design value that has been used in the past). b. What is the total volumetric flow rate (in ft3/m [L/s]) for the airflow needed to deliver this rate of cooling? For this exercise, assume that the supply air temperature is 60°F (16°C) at 90% relative humidity (rh) (enthalpy ~25 Btu/lbm [kJ/kg] dry air, specific volume = 13.3 ft3/lbm [0.83 m3/kg] dry air) and return temperatures is 75°F (24°C) at 50% rh (enthalpy ~28.5 Btu/lbm [66 kJ/kg] dry air). Do this calculation based on · ·  enthalpy . What would the minimum duct the simple formula Q = m cross-section area have to be to keep the velocity inside the duct to less than 3000 ft/m (15 m/s)?

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Table 8.1: Representative Energy Consumption Data for Typical Engineering Classroom/Laboratory Building (Conditioned floor area = 85,000 ft2 [7900 m2])

Use Category

Annual Amount

Units

Space cooling

540,000

kWh

Ventilation

130,000

kWh

Pumps and auxiliary (for HVAC)

150,000

kWh

Heating (or reheat)

3500

MBtu (106 Btu)

Hot water

20,000

kWh

Lighting (interior and exterior)

275,000

kWh

Miscellaneous equipment (laboratory, office, and so on)

215,000

kWh

c. What would be the total volumetric flow rate (in gpm [L/m]) for chilledwater flow needed to deliver this rate of cooling? For this exercise, assume that one gallon of water is equal to 8.34 lbm (3.79 kg), the specific heat of water is 1.0 Btu/lbm·°F (4.19 kJ/kg·K), and that the difference between the supply and return water temperature is 10°F (5.6°C). Do this calculation · ·  c  T . What would the minimum based on the simple formula Q = m p nominal pipe diameter in inches (cm) have to be to keep the velocity inside the pipe to (roughly) less than 3.0 ft/s (0.9 m/s)? 5.

Thermal energy storage (TES) is one method being used to help reduce the total energy consumption of creating chilled water for cooling during peak cooling periods. This exercise helps give an idea of the sizes and capacities needed for a commercial-scale building. a. Compute the water volume storage (gal [L]) needed to provide the equivalent of 100 tons of cooling capacity to supplement a campus cooling network for a total of 6 hours a day (600 ton-h = 7.2 million Btu [2112 kWh]). For this exercise, assume that the difference between the cold water supply and return temperatures from the tank to the chilled-water system is 10°F (5.6° C). b. What would the physical size (dimensions) for a storage tank of this volume be assuming the tank diameter equals the tank height?

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Selecting the appropriate energy source: a. Imagine you have just purchased a new house. You need to select all new appliances, including a clothes drier, water heater, and cooking range. Both electric and natural gas are available for connection at each of the appliance locations. Which energy source do you choose for each appliance—electric or natural gas? What factors influence your decision? b. Imagine you are the designer of a new office building. You need to decide if there should be natural gas brought into the building in addition to an electric service or if an all-electric building would be a better choice. What do you decide? What factors influence this decision? For Further Investigation Study:

(Note that these items require varying levels of complexity in knowledge and technical understanding.) 1.

When making the decision as to what type of heat sink to use for a chiller (either air-cooled or water-cooled), factors to consider include the total capacity of the chiller, space availability for a cooling tower or condenser unit, water scarcity at the location, energy efficiency, and so on. To gain a better understanding of the criteria to use for this decision, conduct the following exercises: a. Identify the design cooling conditions for this campus. b. Making rough simplifying assumptions, compute the compressor power input for an air-cooled versus water-cooled chiller at the design conditions. c. Using simplifying, rule of thumb assumptions, compute the additional energy needed to operate the cooling tower and condenser water system for the water-cooled chiller option. d. Identify and discuss the other factors that would be involved with the decision.

2.

Space cooling using chilled-water distribution systems is often chosen for larger-scale commercial buildings, even though the use of direct exchange (DX) systems such as rooftop units would generally use less energy. a. Why is this? What are the main reasons why this decision is made? b. Identify the major energy consuming components of both chilled-water and DX cooling systems. c. What are the advantages of using chilled-water versus DX cooling systems? d. Estimate the energy usage percentage difference for a typical campus building with chilled-water versus DX cooling.

3.

Identify and describe the electricity pricing structure that exists for your university or school’s campus (this is also termed the electricity rate tariff). How might this electricity rate structure affect the prioritization of the campus energy system design and implementation of overall energy efficiency measures?

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Potential Design Projects: 1.

2.

3.

Identify a location on your campus that is a good candidate for installation of a CCHP. Estimate the total electrical power requirement for this campus (or get this information from the campus facilities management group). Determine or estimate the ideal capacity for a CCHP system based on the location and other local factors. What would the required heat input rate for this system be? Approximately how much waste heat would be generated by this unit when run at its design capacity? Determine the most beneficial use for that heat given the local climate and campus needs. Prepare a set of design sketches showing the location of the CCHP unit(s) and the design for distributing the hot water, steam, and/or chilled water that would be generated with the waste heat. Prepare a simple building energy simulation model for this building using eQUEST, EnergyPlus, or other similar software packages. It could be a simplified model of the building that this class meets in or some other building identified by the instructor. Use this model to compute the predicted annual EUI. If possible, obtain information on the actual energy usage with this building and compare the two. What factors influenced any discrepancies noted between the predicted EUI from your energy model and the actual values? Using a building energy simulation model for the building where this class meets or another available example, compute the energy savings potential for several energy efficiency measures. These could include items such as the addition of daylighting controls and reducing the pressure drop for ventilation and conditioning air delivery by 10%.

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9 Energy: Sources and Generation This is the second of two chapters focusing on the important topic of energy. Chapter 8 covered the conversion, use and delivery of energy within buildings. This chapter discusses the various conventional and renewable energy source options for a building.

9.1

KEY TERMS RELATED TO THIS CHAPTER 

The following key terms are referenced and defined in this chapter: •

Alternating current (or direct current) of electricity (AC or DC)

•

Distributed generation of electrical energy (DG)

•

Gigawatt peak energy production (GWp) (for solar photovoltaic [PV] or wind power systems)

•

Kilowatts or megawatts (kW or MW)

•

(Nearly) net zero energy building

•

PV system for electricity generation

•

Renewable energy credit (REC)

•

Site versus source energy

•

Solar hot water (SHW)

Reflection Exercise: Should a High-Performance Building be Required to Have Some Amount of On-Site Renewable Energy? Whether to have mandatory requirements for renewable energy systems on a building project site is a common topic when developing high-performance green building standards and codes. Similarly, with building certification systems the question is how much incentive to offer (in terms of credit points, and so on.). The options range from having no requirement at all, perhaps with the thinking that the additional cost would not be justified, to mandating that buildings be net zero (or nearly net zero) energy; that is the building generates (nearly) the amount of energy on site as it consumes on an annual basis.

117

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Instructor-Led Discussion: To start the thought process about energy sources for a high-performance building, consider these questions: 1. 2. 3. 4.

Should a high-performance building be required to have at least some amount of renewable energy production on the building project site (that is, should the local building code mandate this)? If so, then how much renewable energy production should be required? Should these requirements apply only to buildings above a certain size or of a certain type? What if the local solar or wind energy resource is not consistent (such as in an area that is often cloudy or at higher latitudes)?

As part of this discussion, there should be consideration of the economics of the installation of an on-site renewable energy system (such as a photovoltaic [PV] array), local cost of electrical energy, tax or other incentives that might be available, renewable energy system conversion efficiency, the resources availability for the building location (solar, wind, biomass, hydro), the goals for how fast renewable energy should be integrated into the energy production mix in society, and so on. All of these factors will help determine a comparative metric for determining how much renewable energy generation is ideal for this site and building project. Real-World Example Discussion: In the initial development of ASHRAE Standard 189.1, Design of High-Performance Green Buildings (which is now the technical basis for the IgCC), these very questions were considered. The committee responsible for developing that standard decided that, at the time, the installation of on-site renewable energy should not be made mandatory, but that the building should make provisions for future installation of a renewable energy system. The committee then also had to decide for what capacity the renewable energy system should be planned and what baseline should be used in the specification. A convenient frame of reference metric was determined to be the roof surface area, because that is an easily determined quantity from the building plans and the amount of solar energy available is known as a function of the site land area. The requirement put forth in the standard is that the sum total of on-site renewable energy annual production must be at least 6000 Btu/ft2·y (20 kWh/ m2·y) for a singlestory building and 10,000 Btu/ft2·y (32 kWh/m2·y) for a building taller than one story. This was roughly based on the following assumptions: that one-half the roof area could be allocated to an on-site renewable energy system, a minimum PV panel conversion efficiency of 13%, and operation in a midlatitude environment with typical solar energy resources.

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Commentary: This discussion points out how complicated the issues might be when making decisions concerning what energy sources should be and whether this highperformance building should consider on-site renewable energy for their energy mix.

9.2

ENERGY SOURCES—GENERAL DISCUSSION 

There are often discussions about using renewable energy sources as a way to power the world, but the world has been slow to actually implement renewable energy for a number of reasons. This chapter focuses on ways to use renewable energy to offset nonrenewable energy sources. Various definitions of a renewable energy source exist; for example the IgCC/189.1 defines on-site renewable energy systems as “photovoltaic, solar thermal, geothermal energy, and wind energy systems … located on the building project” (ICC 2018a). A European Union directive in 2009 specified that the renewable energies are: wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas, and biogases (European Commission 2010). Passive solar and energy efficiency measures are not included to avoid double counting. This is in contrast to the common nonrenewable energy sources, such as fossil fuels (coal, oil, natural gas) and nuclear power. The use of renewable energy is differentiated between generating and using the energy source on site versus paying for a renewable resource generated elsewhere. Today, many utility companies offer the ability to purchase renewable energy credits (RECs) from their generation portfolio or via the open market. RECs are a market-managed solution to allow building owners to take credit for supporting the inclusion of renewable energy systems into the grid. Owners can purchase the credits as certifiable proof that an amount of electrical power provided to the grid comes from a renewable energy source (one REC = 1 MWh of electrical energy for consumption). These utilities generate renewable energy with large-scale wind or solar facilities. Figure 9.1 shows the sources of primary energy used in the United States for 2017, with a breakdown by percentage of the total for each source. From this figure, note that renewable energy sources accounted for 11% of total energy consumption and 17% of the total electricity generation in the United States in 2017. Renewable energy production exceeded 11 quadrillion Btu in 2017. Of that, about 24 billion kWh of electricity was produced in 2017 from small-scale (distributed) solar PV systems (