Effect of floor coverings in radiant heating

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EFFECT OF FLOOR COVERINGS IN RADIANT HEATING

A T h esis P r e s e n te d to the F a c u lty o f the Sch ool o f E n g in eerin g The U n i v e r s i t y

o f Southern C a l i f o r n i a

In P a r t i a l F u l f i l l m e n t o f th e R eq u irem en ts f o r th e Degree M aster o f S c ie n c e i n M echanical E n g in e e r in g

by James M. A p p e l g a t e and Raymond Edwin G e i s s e r A u g u s t 1950

UMI Number: EP60501

All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion.

UMI D issertation P u blishin g

UMI EP60501 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code

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This thesis, w ri tt en by

James M. A p p e l g a t e Raymond Edwin G e i s s e r

under the gui dance ofVi.&X.r. F acu lty C o m m i t t e e , and a p p r o v e d by all its m e m be rs , has been pr ese nte d to an d a c c e p te d by the Co unc il on Grad ua te S t u d y an d Rese arc h in p a r ti a l fulfillment of the requirements f o r the degree of

ienee..JLn Mecha

Faculty Committee

erin g

AC KNOWLE DGEMENTS

The a u t h o r s w i s h t o e x p r e s s t h e i r a p p r e c i a t i o n t o t h e Rug D e p a r t m e n t o f B u l l o c k ' s o f Los A n g e l e s f o r t h e l o a n of a l l

t e s t specim ens u sed in t h i s i n v e s t i g a t i o n .

TABLE OF CONTENTS CHAPTER I.

PAGE

THE PROBLEM AND DEFINITIONS OF TERMS USED . . . . The p r o b l e m

1

..................................................................................

1

S t a t e m e n t o f t h e p r o b l e m ...............................................

1

I m p o r t a n c e o f t h e s t u d y ....................................................

1

D e f i n i t i o n s o f t e r m s u s e d ....................................................

3

Mean p a n e l t e m p e r a t u r e

................................................

.

3

Mean p a d t e m p e r a t u r e .........................................................

3

Mean r u g t e m p e r a t u r e ...................................................

3

E m issivity

.............................................................................

3

R a d i a n t h e a t i n g ........................................................................

3

C o n d u c t i o n .................................................................................. Mean r a d i a n t t e m p e r a t u r e

..............................................

A

..................................................................................

^

.......................................................................................

A

.......................................................................................

5

..................................................................................

5

REVIEW OF THE L I T E R A T U R E .........................................................

7

Theory o f r a d i a n t h e a t i n g ....................................................

7

C arpetin g

8

C on vection Pad

EVT

Rug A T Therm opile II.

III.

THE CONSTRUCTION, TECHNIQUE C on stru ction

INSTRUMENTATION AND TESTING

....................................................................................... . . . . . .

12 12

iii CHAPTER

PAGE I n s t r u m e n t a t i o n ............................................................... T e stin g technique

. . . . . . .

.

16

.....................................

D e s c r i p t i o n o f a t y p i c a l t e s t run f o l l o w s IV.

.

.

17

.

18

.

20

...................................................................

20

EXPERIMENTAL R E S U L T S .......................................................... C om p ariso n o f h e a t d e l i v e r e d by r a d i a t i o n f r o m the ru g s t e s t e d Pad A T ‘ s

23

Rug A T ' s

23

Temperature g r a d i e n t surface

su r fa c e to rug

...................................................

Therm opile r e s u l t s V.

from p a n e l

31

...................................................................

31

DISCUSSION OF EXPERIMENTAL RESULTS ANDCONCLUSIONS

44

H eat d e l i v e r e d by r a d i a t i o n from t h e

rugst e s t e d

Pad

A T 1s

.................................................................................. .

45

Rug

A T 1s

.......................................................................................

46

T e m p e r a t u r e g r a d i e n t from p a n e l s u r f a c e surface VI.

44

to rug

......................................................................................

SUMMARY

BIBLIOGRAPHY

48 49

......................................................................................................

52

LIST OF TABLES TABLE I. II.

PAGE P r o p e r t i e s o f T e st Specim ens

....................................

6

P a n e l S u r f a c e T e m p e r a tu r e and H e a t D e l i v e r e d by R a d i a t i o n f o r Rug S u r f a c e T e m p e r a t u r e o f 8 5 ° F. **7

LIST OF FIGURES FIGURE

PAGE

1.

T est Setup .

.

.

.

................................................................1 3 - 1 4

2.

H e a t D e l i v e r e d by R a d i a t i o n From t h e Rugs T e s t e d ...........................................

.

21

3.

Pad

^ ‘T *s When U s e d w i t h

Rug A

................................

24

A.

Pad

^ T ’ s When U s ed w i t h

Rug B

................................

25

5.

Pad

Z ^ T 's When U s ed w i t h

Rug C

................................

26

6.

Pad

Z l T ' s When U s e d w i t h

RugD

................................

27

7.

Rug

Z M ' s When U s e d w i t h

Pad E

................................

28

8.

Rug

^ T ' s When U s e d w i t h

Pad F

................................

29

9.

Rug

ZSiT*s When U s e d w i t h

Pad G

................................

30

10.

T e m p e r a t u r e V e r s u s H e a t Output Pad E 8c Rug A *

32

11.

T e m p e r a t u r e Versus H e a t O utput Pad F 8c Rug A .

33

12.

T e m p e ra tu r e V e rs u s

Heat

O u t p u t Pad G & Rug A .

34

13*

Temperature Versus

Heat

O u tp u t Pad E 8c Rug B .

35

14.

T e m p e ra tu r e Versus

Heat

Output Pad F 8c Rug B .

36

15.

Temperature Versus

Heat

Output Pad G 8c Rug B .

37

16.

T e m p e ra tu r e V e r s u s

Heat

Output Pad E 8c Rug C .

38

17.

T e m p e r a t u r e V e rs u s

H ea t

O utp ut Pad F & Rug C .

39

18.

T e m p e r a t u r e Versus

Heat

O u t p u t Pad G 8c Rug C .

40

19*

T e m p e r a t u r e V e rs u s

H eat

O u t p u t Pad E & Rug D .

41

20.

T e m p e ra tu r e Versus

Heat

O u tp u t Pad F 8c Rug D .

42

21.

Temperature Versus

Heat

O utp ut Pad G 8c Rug D .

43

CHAPTER I THE PROBLEM AND DEFINITIONS OF TERMS USED In d e s i g n i n g r a d ia n t h e a t i n g s y s t e m s f o r r e s i d e n t i a l u n its,

the e f f e c t

been d e f i n i t e l y

o f c a rp etin g over a f lo o r pan el has never

estab lish ed . I.

THE PROBLEM

Statem ent o f the problem . in v estig a tio n

(1)

I t was t h e p u r p o s e o f t h i s

t o compare s e l e c t e d c o v e r i n g s on t h e b a s i s

o f t e m p e r a t u r e g r a d i e n t from h e a t i n g p a n e l s u r f a c e carpet surface;

(2)

to determ ine

the h e a t o u t p u t p e r u n i t

a r e a o f v a r io u s comm ercial f l o o r c o v e r in g s ; t a i n e m i s s i v i t y v a lu e s o f the d i f f e r e n t Im portance o f the s t u d y .

to top

and ( 3 )

t o ob­

t e s t specim ens.

C o n tem p o ra ry d e s i g n p r a c ­

tice

o f r a d ia n t h e a t i n g f l o o r p a n e l s h a s been e i t h e r t o i g ­

nore

the e f f e c t o f th e f l o o r c o v e r in g s o r to handle

e f f e c t w ith a fa c to r of safety* more t h a n a random g u e s s less

T h is

th eir

f a c t o r o f t e n was no

o a s e d t o some e x t e n t on more o r

c a su a l o b serv a tio n s o f p reviou s ra d ia n t f lo o r panel

in sta lla tio n s. T e s t s o f t h e A m e rica n S o c i e t y o f H e a t i n g and V e n t i l ­ a t i n g E n g i n e e r s h a v e I n d i c a t e d t h a t t h e maximum f l o o r s u r f a c e tem perature th a t

may be w a l k e d on c o n t i n u o u s l y w i t h c o m f o r t

2 t o t h e a v e r a g e human b e i n g i s str u c tio n con d ition s

85° F.^

(con crete

fou r in ch es of crushed r o ck ),

Under a v e r a g e c o n ­

f lo o r p a n el l a id over at l e a s t t e s t s h a v e i n d i c a t e d t h a t th e

maximum mean w a t e r t e m p e r a t u r e w i t h i n t h e p r o p e r d e s i g n c o n p

d i t i o n s v a r i e s f r o m 1 0 0 ° F. course,

is

t o 1 2 0 ° F.

b a s e d on a b a r e c o n c r e t e

I f the

flo o r panel i s

This r a n g e ,

of

flo o r.

covered e it h e r w ith w a l l - t o -

w a l l c a r p e t in g o r w it h a normal f u l l - s i z e d rug,

the major

p o r t i o n of the r a d i a n t p a n e l i s changed in c h a r a c t e r s i n c e now t h e s u r f a c e

is

crete

A lso,

surface.

o f some t y p e .

Hence,

c o n t a i n numerous surface

I f th is i s

the ru g i s u s u a l l y

sm all a i r sp a c e s,

b a c k e d w i t h a pa d

it

is

l o g i c a l to e x p e c t the

surface. the c a s e ,

8 5 ° F. a t t h e r u g s u r f a c e ,

T h is,

not th e smooth con­

in a s m u c h a s b o t h t h e pad and t h e rug

t h e maximum a l l o w a b l e

surface

o f the ru g,

t e m p e r a t u r e o f t h e r u g t o be a t a l o w e r t e m p e r a t u r e

than the c o n c r e te

tain

the p i l e

a n d an a t t e m p t i s made t o main­ occupied su rfa ce

tem perature o f

i t w o u ld be e x p e c t e d t h a t t h e

t e m p e r a t u r e o f t h e c o n c r e t e p a n e l c o u l d be r a i s e d .

o f c o u r s e , w ould i n c r e a s e

the nom inal r a t i n g o f the

1 W i l l i a m S e v e r n s and J u l i a n F e l l o w s , H e a t i n g , V e n t i l a t ­ i n g and A i r - C o n d i t i o n i n g F u n d a m e n t a l s , S e c o n d E d i t i o n (New York: John W i l e y esc S o n s , 1 9 ^ 9 ) j p . 381* 2 H e a t i n g V e n t i l a t i n g A i r - C o n d i t i o n i n g G u i d e , (New York: A m e rica n S o c i e t y o f H e a t i n g and V e n t i l a t i n g E n g i n e e r s , 19^9)» p. 6 2 6 .

3 h ea tin g p an el,

sin ce

in a l l

such c a s e s

it

e q u i l i b r i u m c o n d i t i o n s have been o b t a i n e d . t h e r u g and p a d a r e ,

therefore,

i s assumed t h a t The e f f e c t o f

im portant c o n s id e r a t io n s in

the d e s ig n o f a ra d ia n t f l o o r p a n el h e a t in g system . II.

DEFINITIONS OF TERMS USED

Me an P a n e l T e m p e r a t u r e .

This tem p erature i s

the

a v e ra g e s u r f a c e tem p erature o f the h e a t i n g p a n e l. Mean Pad T e m p e r a t u r e . p r e te d as the s u r fa c e

This tem p er a tu r e w i l l

be i n t e r ­

t e m p e r a t u r e o f t h e r u g pad f a r t h e s t

away from t h e h e a t i n g p a n e l . Mean Rug T e m p e r a t u r e .

T his tem p erature i s

the aver­

age s u r f a c e tem p er a tu r e o f t h e s i d e o f th e rug f a r t h e s t away from t h e h e a t i n g p a n e l . E m lssivlty. a c tu a l surface to

The r a t i o

o f t h e e m i s s i v e power o f an

t h a t o f a b la c k body.

R adiant H e a t i n g .

R a d i a n t h e a t i n g may be d e f i n e d a s

a n y m eth o d o f r a i s i n g t h e t e m p e r a t u r e o f an o b j e c t o r o f c r e ­ a tin g

t h e s e n s a t i o n o f h e a t by means o f r a d i a n t e n e r g y waves

^ W i l l i a m H. McAdams, H e a t T r a n s m l s s i o n , S e c o n d E d i t i o n , (New York: McG-raw-Hill, 1 9 ^ 2 ) , p . ^9*

from a so u rc e w h ic h i s a t a h i g h e r te m p e r a tu r e than th e r e A c e i v i n g bo d y. C onduction.

C onduction i s

t h e t r a n s f e r o f h e a t from

one p a r t o f a body t o a n o t h e r p a r t o f t h e same b o d y ,

o r from

one body t o a n o t h e r body i n p h y s i c a l c o n t a c t w i t h t h e f i r s t , w ith ou t a p p reciab le

d isp la c e m e n t o f the p a r t i c l e s

of eith er

body.-^ Mean R a d i a n t T e m p e r a t u r e . a ll lo ss

"A u n i f o r m t e m p e r a t u r e o f

the s u r r o u n d in g s u r f a c e s w h ic h w ould r e s u l t (or gain)

o f h e a t by r a d i a t i o n a s t h a t to

i n t h e same ( o r from )

t h e same o b j e c t s and s u r f a c e s a t t h e i r a c t u a l s u r f a c e

tem­

peratu res. C on vection.

C o n v e c t i o n i s t h e t r a n s f e r o f h e a t from

one p o i n t t o a n o t h e r w i t h i n a f l u i d , m i x i n g o f one p o r t i o n o f t h e Pad A surface

T.

gas or l iq u id , 7 f l u i d w ith another.

The p a n e l s u r f a c e

tem perature,

t e m p e r a t u r e minus t h e pad

° F.

A

T. N a p i e r Adiam, R a d i a n t H e a t i n g , d u s t r i a l P r e ss, 19^7), p. 10. -’McAdams,

op. c i t . , p.

S e v e r n s and F e l l o w s , 7

by the

McAdams, o&. c i t . , p .

(New York:

1. op. 1*

c i t . , p.

3^3*

The I n ­

Rug A

T.

The pad s u r f a c e t e m p e r a t u r e minus t h e rug

su r fa c e tem perature, T herm opile.

0 F. A th erm op ile i s a r a d ia n t h ea t-m ea su rin g

instrum ent h avin g a m od ified , reflecto r. ened,

The “h o t "

p arob olic

j u n c t i o n s , w i r e d i n s e r i e s and b l a c k ­

are l o c a t e d a t th e f o c u s o f the r e f l e c t o r . T a b le I d e s c r i b e s

m ent.

h igh ly p o lish ed ,

the specim ens u sed in t h i s

exp eri­

6

TABLE I PROPERTIES OF TEST SPECIMENS

Test Specim en

W eight, # / sq. f t .

T h ick n ess, inch es

Remarks

Rug A

0.801

15 /1 6

An e x p e n s i v e r u g h a v ­ in g a flow ered design In two t y p e s o f weave on i t s s u r f a c e . G-reei

Rug B

0.407

3 /8

A p l a i n green rug in the in e x p e n s iv e p r ic e range.

Rug C

0.459

5/16

A p l a i n gr a y r u g h a v ­ in g a rid g e p a tte r n . M edium -price r a n g e .

Rug D

0.4 6 3

5 /8

A p l a i n blue rug hav­ i n g an e s p e c i a l l y l o o i weave. In expensive p r ic e range.

Pad E

0.289

1/4 (across rid g es)

A t y p i c a l w a f f l e pad.

Pad F

0.627

3/16

A s p o n g e - r u b b e r pa d .

Pad Gr

0 .2 2 7

3 /8

A ty p ica l f e l t

pad .

CHAPTER IX REVIEW OF THE LITERATURE I.

THEORY OF RADIANT HEATING

Radiant h e a t i n g i s

a r ela tiv e ly

i n g s y s t e m s a s we know them t o d a y .

new i n n o v a t i o n

However,

in h e a t­

in the r u i n s

o f t h e Roman B a t h s i n E n g l a n d r a d i a n t h e a t i n g s y s t e m s have been d is c o v e r e d .

One o f t h e

in sta lla tio n s

used the system

o f p a s s i n g warm a i r b e n e a t h t h e f l o o r * I n t h e e a r l y n i n e t e e n h u n d r e d s r a d i a n t h e a t i n g was a ga in put in to u se . land.

I t s m o s t e x t e n s i v e u s e h a s b e e n i n Eng­

At t h e p r e s e n t tim e r a d i a n t h e a t i n g i s

p o p u la r system o f

heating

I f a p la in

e ffectiv ely

in the U n ite d S t a t e s .

mercury t h e r m o m e t e r i s

sunny day, a s im p le

p lace

it

t a k e n o u t s i d e on a

e x p e r i m e n t c a n be c o n d u c t e d t h a t w i l l

dem onstrate the v a lu e o f r a d ia n t en ergy.

t h e t h e r m o m e t e r and s h i e l d i t peratu re.

Then t a k e t h e d irectly

from t h e s u n .

t h e r m o m e t e r o u t o f t h e s h i e l d and

in the sun.

A tem perature in c r e a s e

o f ap­

T his i n c r e a s e

t e m p e r a t u r e i s due t o r a d i a n t e n e r g y from t h e s u n . In r a d i a n t

flow

Take

R e c o r d t h i s tem­

p r o x i m a t e l y t w e n t y p e r c e n t w i l l be n o t i c e d . in

b e c o m i n g a more

takes p lace

heating, is

t h e medium t h r o u g h w h i c h t h e h e a t

not h e a te d .

Radiant h e a t e n e rg y i s

g o v e r n e d by t h e same l a w s a s l i g h t ;

i.

e .,

i t has a s p e e d

8 o f a p p r o x i m a t e l y 1 8 6 , 0 0 0 m i l e s p e r s e c o n d and i t

tra v els

in a s t r a ig h t lin e * A ll s u b s ta n c e s em it r a d i a t io n ,

t h e amount d e p e n d i n g

on t h e p r o p e r t i e s o f th e r a d i a t i n g b o d y . The wave l e n g t h o f r a d i a t i o n h e a t v a r i e s from l o n g waves to sh o r t w aves.

The s h o r t w a v e s a r e do m inant a t h i g h

t e m p e r a t u r e s and t h e l o n g w a v e s a t l o w t e m p e r a t u r e s .

We w i l l

concern o u r s e lv e s here w ith the long w aves. The r a t e

o f h e a t l o s s by r a d i a t i o n d e p e n d s upon t h e

e x p o s e d s u r f a c e a r e a o f t h e b o d y and upon t h e d i f f e r e n c e b e t w e e n t h e mean s u r f a c e mean s u r f a c e objects.

t e m p e r a t u r e o f t h e body and t h e

tem perature o f

the su r r o u n d in g w a l l s or o t h e r

2

II.

CARPETING

C a r p e t s a r e d e s i g n e d f o r t h e i r a p p e a r a n c e and w e a r i n g q u a lity .

Most o f t h e c a r p e t i n g i n u s e t o d a y h a s a s u r f a c e

of carpet w ools.

C a r p e t w o o l s number a r o u n d two h u n d r e d o r

more d i f f e r e n t t y p e s ,

a l l o f w h i c h a r e i m p o r t e d to t h e U n i t e d

States. The c o n s t r u c t i o n o f t h e weave p l a y s

an i m p o r t a n t p a r t

1 Max Ja ko b and George H a w k in s, E l e m e n t s o f H e a t T r a n s f e r and I n s u l a t i o n t (New York: John W ile y & Hons, 19^-2) ^H e a t i n g V e n t i l a t i n g A i r - C o n d i t i o n i n g Guide (New York: A m e r i c a n S o c i e t y o f H e a t i n g and V e n t i l a t i n g E n g i n e e r s , 19^9)> p. 615.

9 in th e wear l i f e tio n

Wear i s a f u n c ­

the f a b r ic ;

t h e more

the l o n g e r wear l i f e . The p i l e

for

from a c a r p e t .

o f t h e amount o f w o o l w ov e n i n t o

w ool,

life

ob tain able

depth i s d i r e c t l y p r o p o r tio n a l

in a c a r p e t ,

o t h e r f a c t o r s i n th e c a r p e t b e i n g e q u a l ;

exam ple, p r o v i d i n g a l l

are i d e n t i c a l ,

t o t h e w e ar

sp ecifica tio n s

a n d one c a r p e t i s

except denseness

tw ice as dense as a n o th e r ,

i t w i l l wear f o u r tim es as l o n g . Pads a r e n o r m a l l y u s e d b e n e a t h a r u g t o l e n g t h e n th e wear l i f e that

o f the rug.

The b e s t pad t o p r o m o te l o n g w e a r i s 4 made o f s p o n g e r u b b e r . The c a r p e t r e c e i v e s h e a t from t h e p a n e l by c o n d u c t i o n

th r o u g h the pad,

then t h i s h e a t i s g iven

c o m b i n a t i o n o f c o n v e c t i o n and r a d i a t i o n .

t o t h e room by a The r a t i o

o f the

h e a t g i v e n t o t h e room by c o n v e c t i o n and r a d i a t i o n from a smooth c o n c r e te p a n e l v a r i e s

o v e r a wide r a n g e ,

depending

m a i n l y upon t h e a i r c u r r e n t s i n t h e room and t h e d i f f e r e n c e b e t w e e n th e p a n e l s u r f a c e

t e m p e r a t u r e and t h e mean r a d i a n t

tem perature o f the su rro u n d in g s. heat

An a p p r o x i m a t e r a t i o

of

t r a n s f e r fro m a p a n e l o f 4 5 p e r c e n t by c o n v e c t i o n and

O l i v e r P. B e c k w i t h , "C arp et C o n s t r u c t i o n and I n s t a l l a ­ t i o n , " J o u r n a l o f t h e S o c i e t y o f M o tio n P i c t u r e E n g i n e e r s , 5 0 : 4 2 8 , May, 1 9 5 8 . 4 I b i d . , p . 429*

10 55 p e r c e n t by r a d i a t i o n i s a room h a v i n g a mean r a d i e n t

g i v e n by S e v e r n s and F e l l o w s t e m p e r a t u r e o f 6 5 ° F.

5

for

and an

a m b i e n t a i r t e m p e r a t u r e o f 7 0 ° F. The r a t i o o f h e a t t r a n s f e r from a c a r p e t e d p a n e l s u r ­ face p resen ts d if f e r e n t fig u r e s ,

the p r e c i s e

ra tio

e v a l u a t e d to d a t e .

not having been d e f i n i t e l y

figu res

o f the H owever,

Adlamb p o i n t s o u t t h a t w i t h a c a r p e t e d p a n e l t h e h e a t g i v e n o f f by c o n v e c t i o n

i s g r e a te r in proportion

than h e a t g iv e n

o f f by c o n v e c t i o n from a s m o o t h s u r f a c e b e c a u s e o f t h e more t u r b u l e n t f lo w a c r o s s the rough rug s u r f a c e * Since surface, in a l l

the p i l e

i t g ives

d irectio n s.

a more p l e a s i n g

o f a c a r p e t p r e s e n t s a rough r a d i a t i n g

o f f d if f u s e d radiant h e a t rays t r a v e lin g These d i f f u s e d r a y s from t h e p i l e

sen satio n

fro m t h e sm o o th p a n e l .

produce

tnan the u n i d i r e c t i o n a l h e a t r a y s

The p i l e

unevenness o f a carp et a lso

p r e s e n t s a g r e a t e r r a d i a t i n g a r e a than d o e s a sm o oth p a n e l . The i n s u l a t i n g q u a l i t i e s

o f a c a r p e t and pad a f f e c t

a p a n e l i n s u c h a way t h a t more h e a t i s

l o s t th ro u g h th e bottom

o f a c a r p e t e d p a n e l than a bare p a n e l .

The r e d u c t i o n i n h e a t

5 ^ W i l l i a m S e v e r n s and J u l i a n F e l l o w s , H e a t i n g , V e n t i l a t ­ i n g a n d A i r - C o n d i t l o n l n g F u n d a m e n t a l s , S e c o n d E d i t i o n ( New York: John W i l e y dc S o n s , 1 9 ^ 9 ) , p . 3 o 8 . 6 T. N a p i e r Adlam, R a d i a n t H e a t i n g , (New York: The I n d u s ­ t r i a l P r e s s , 1 9 ^ 7 ) , p. 25^.

11 o u t p u t due t o i n c r e a s e d l o s s

through th e bottom f o r an average

c a r p e t may be a s s u m e d a s n o t more t h a n f i v e 7 a s com p a red w i t h a b a r e p a n e l .

to ten p e r c e n t

The u s e o f s c a t t e r r u g s i n s t e a d o f w a l l - t o - w a l l c a r ­ p e t i n g i s n o t a d v i s e d b e c a u s e t h e maximum s u r f a c e t e m p e r a t u r e o f 8 5 ° F.

on t h e

f l o o r w i l l produce a r e l a t i v e l y

t e m p e r a t u r e on t h e

s c a tte r rugs.

c o ld surface

The r e d u c t i o n i n h e a t o u t ­

p u t when u s i n g s c a t t e r r u g s i n s t e a d o f a b a r e f l o o r p a n e l i s , on t h e a v e r a g e ,

25

to 30 p er c e n t.

7i b i a . , p.

257.

8 i b i a . , p.

259.

8

CHAPTER I I I THE CONSTRUCTION, INSTRUMENTATION AND TESTING TECHNIQUE I.

CONSTRUCTION

The d e s i g n o f t h e t e s t by t h e

setup

( F i g u r e 1) was g o v e r n e d

f o l l o w i n g c o n s i d e r a t i o n s : (1)

the h ig h e s t p e rcen ta g e

o f h e a t p o s s i b l e p a s s in g through the t e s t mum a i r v e l o c i t i e s (3)

specim en;

(2) m ini­

o v e r t h e s p e c i m e n and i n t h e t e s t c e l l ;

e q u i l i b r i u m c o n d i t i o n s o b t a i n e d i n a minimum amount o f

tim e;

and (4-) t h e

t e s t setu p c o n s tr u c te d to sim u late

actu al

flo o r panel in s t a lla t io n s . The h e a t i n g u n i t c o n s i s t e d o f a c e l o t e x box and an aluminum p l a t e .

The b o t t o m a n d s i d e s

s t r u c t e d o f two l a y e r s o f -J-*1 c e l o t e x . to m inim ize h e a t l o s s e s

o f t h e box w e r e c o n ­ Two l a y e r s w e r e u s e d

t h r o u g h t h e box s o t h a t t h e maximum

amount o f h e a t w o u l d f l o w t h r o u g h t h e t e s t

specim en.

The

p a n e l s u r f a c e was made o f 3 / 1 6 " p l a t e o f aluminum.

Attached

to t h i s were e i g h t

Th ese

1 5 0-w att C alorox S t r i p H ea te rs.

w ere p l a c e d on 9 11 c e n t e r s , as n e a r ly as p o s s i b l e

a s shown i n F i g u r e I d ,

an a c t u a l p i p e i n s t a l l a t i o n ;

t h e h i g h c o n d u c t i v i t y o f t h e aluminum d i d n o t g i v e panel surface

tem perature v a r i a t i o n s .

to sim ulate however, the d e s i r e d

13

F igu re lb F igure 1 T est Setup

S

T & iE fiP M O COUS^LES

t

tt)

3 3

Figu:*e

*3 ( H e a t i m t Pam? i j TEST SETUP

/ k V /^ /it e A

“TiSr/PS

Adlam

c o n d u c t e d e x p e r i m e n t s on a c o n c r e t e p a n e l w i t h

c o n s t a n t mean w a t e r t e m p e r a t u r e ,

room a i r

s u r r o u n d i n g mean r a d i a n t t e m p e r a t u r e .

tem perature,

and

For p i p e s on n i n e -

i n c h c e n t e r s a n d p l a c e d one i n c h b e l o w t h e p a n e l s u r f a c e , t h e a v e r a g e t e m p e r a t u r e v a r i a t i o n was 2 4 * 5 ° F. b e t w e e n t h e average

surface

the average

tem perature taken d i r e c t l y

surface

a bove t h e p i p e s and

tem p erature taken betw een the p i p e s .

For

p ip es placed three

i n c h e s b e l o w t h e p a n e l s u r f a c e and on

n in e-in ch cen ters,

the average su r fa c e tem perature v a r ia t i o n s

w e r e o n l y 6 ° F. The u p p e r bo x was c o n s t r u c t e d o f one l a y e r o f •§■" c e l o ­ tex. a fia t

A ll in te rio r

s u r f a c e s o f t h e t o p bo x w ere p a i n t e d w i t h

b l a c k p a i n t so t h a t i t w o u ld a b s o r b t h e r a d i a t i o n .

The e n t i r e t o p box was a i r - t i g h t . O penings were d r i l l e d t i o n s o f therm om eters,

i n b o th b o x es f o r the i n s t a l l a ­

t h e r m o c o u p l e w i r e s and e l e c t r i c a l l e a d s .

At e a c h p l a c e where a t h e r m o c o u p l e was t o be a t t a c h e d t o t h e s u r f a c e o f t h e aluminum p l a t e , d r ille d .

(S e e F i g u r e I d ) .

two s m a l l h o l e s were

Very f i n e w i r e was drawn t h r o u g h

the h o l e s to h o l d the th e rm o c o u p les. The t e s t c e l l ,

f o r m e r l y a c o l d s t o r a g e room,

in which

t h e a p p a r a t u s was p l a c e d d u r i n g t h e a c t u a l e x p e r i m e n t a t i o n was l o c a t e d in the basem ent o f t h e E n g in e e r in g B u ild in g o f the U n iv e r s it y o f Southern C a l i f o r n ia .

The l o c a t i o n a n d t h e

T. N a p i e r Adlam, R a d i a n t H e a t i n g , t r i a l P r e s s , 19^7)> p . 2 1 9 .

(New York:

The I n d u s ­

16 heavy i n s u l a t i o n mum v a r i a t i o n

o f t h e w a l l s o f t h e t e s t c e l l g a v e a m axi­

i n t e m p e r a t u r e o f 3 ° F.

throughout the t e s t i n g

p erio d . II.

INSTRUMENTATION

The s t r i p h e a t e r s w e r e w i r e d i n p a r a l l e l t o t h e p a n e l . T h i s s y s t e m a s s u r e d t h e same amount o f e l e c t r i c a l e n e r g y t o e a c h s t r i p h e a t e r and ,

therefore,

a u n ifo rm h e a t e r tem perature*

To m easure t h e p o w e r i n p u t t o t h e h e a t i n g u n i t , W e sto n E l e c t r i c a l I n s t r u m e n t C o r p o r a t i o n v o l t m e t e r , ^33,

was u s e d .

model

T h i s was c o n n e c t e d i m m e d i a t e l y b e f o r e

l e a d s e n t e r e d t h e l o w e r b ox a n d a c r o s s t h e c i r c u i t .

a

the The

c u r r e n t was m e a s u r e d by a W eston E l e c t r i c a l I n s t r u m e n t Cor­ p o r a t i o n ammeter,

m odel 155*

T h i s was c o n n e c t e d i n s e r i e s on

t h e p o w er i n p u t l i n e . A G e n e r a l Rad io Company Y a r i a c , 50-60

cy cle,

Type 20 0-C 115V,

5 amps, was u s e d t o v a r y t h e l o a d .

Three T a y l o r I n s t r u m e n t Company m e r c u r c y t h e r m o m e t e r s w i t h a r a n g e o f 20 t o 1 2 0 ° F.

( 0 . 5 ° d i v i s i o n ) were u s e d to

m e a s u r e room t e m p e r a t u r e a n d u p p e r box t e m p e r a t u r e s . therm om eters in

The

th e u p p e r b o x were p l a c e d t o o b t a i n t h e a v e r ­

a g e u p p e r box a i r

tem perature,

a s shown i n F i g u r e l a and l b .

One T a y l o r I n s t r u m e n t Company m er cu ry t h e r m o m e t e r w i t h a r a n g e fro m 2 0 ° t o 2 2 0 ° F. sure

th e lo w e r box a i r

(1 .0 ° d iv isio n )

tem perature*

was p l a c e d t o mea­

17 To m ea sure t h e r a d i a t i o n from t h e c a r p e t i n g , tral S cien tific

Company C a t a l o g No.

p i l e was e m p l o y e d .

a Cen­

8 1 0 ? 0 R a d i a t i o n Thermo­

The t h e r m o p i l e was s u s p e n d e d from t h e t o p

o f t n e upper box so t h a t i t s

field

o f v i s i o n w ould j u s t c o v e r

t h e a r e a o f t h e r u g e n v e l o p e d by t h e u p p e r b o x . In m e a s u r i n g t h e s u r f a c e pad,

and p a n e l ,

couple p les

lead s,

tem p eratures o f the rug,

L e e d s and N o r t h r u p c o p p e r - c o n s t a n t a n therm o­

s p o o l No. 5 i+30^ - 1 2 w ere u s e d .

The t h e r m o c o u ­

on t h e pad w e r e p l a c e d i m m e d i a t e l y o v e r t h e t h e r m o c o u p l e s

on t h e p a n e l and t h e t h e r m o c o u p l e s on t h e o v e r t h e t h e r m o c o u p l e s on t h e p a d .

rug im m ed ia te ly

The t h e r m o c o u p l e s w e r e a t ­

t a c h e d t o t h e p a n e l by t h e w i r e h o l d e r s a n d t h e p a d and rug th e r m o c o u p le s were a f f i x e d w i t h t h r e a d . The e l e c t r o m o t i v e

f o r c e c r e a t e d by t h e h e a t t o

the

t h e r m o c o u p l e s and t h e r m o p i l e was m e a s u r e d by a Brown P o r t a b l e P oten tiom eter, co ld

Model No.

1112.

The m o del had an a u t o m a t i c

ju n c tio n com pensating d e v ic e . III. The f i r s t

necessary

TESTING TECHNIQUE

s t e p was t o d e t e r m i n e

to r ea c h e q u ilib r iu m .

t h e l e n g t h o f tim e

The t e s t

s e t u p was o r i g i n a l l y

l o c a t e d i n a b u i l d i n g where t h e r e was a l a r g e a m b i e n t room t e m p e r a t u r e w i t h t i m e .

flu ctu a tio n of

T h i s was r e m e d i e d by

m o v i n g t o t h e c o l d s t o r a g e room where a maximum f l u c t u a t i o n o f 3 ° F.

( 7 2 ° F.

t o 7 5 ° F . ) was r e c o r d e d t h r o u g h o u t t h e t e s t

18 p erio d .

For t h e c o m b i n a t i o n s o f Pad G- p l u s Rug D and Pad

F p l u s Rug C, e i g h t - h o u r t e s t s w ere run w i t h r e a d i n g s

taken

on a l l

Rug D

instru m en ts every f i f t e e n

m inutes.

Pad G- p l u s

t o o k 2 h o u r s and 4 5 m i n u t e s t o r e a c h e q u i l i b r i u m a f t e r an in crease

i n h e a t i n p u t , w h i l e Pad F p l u s Rug G t o o k two h o u r s

to reach eq u ilib r iu m . allow at le a s t

From t h e s e two r u n s i t was d e c i d e d t o

fo u r hours between r e a d in g s .

D e s c r i p t i o n o f a t y p i c a l t e s t run f o l l o w s :

The pa d

was p l a c e d on t h e p a n e l and t h e t h e r m o c o u p l e s a f f i x e d lo ca tio n s

shown i n F i g u r e I d .

The r u g was p l a c e d on t h e p a d

and t h e t h e r m o c o u p l e s a f f i x e d . on t h e r u g .

The u p p e r box was t h e n p l a c e d

T h i s p o s i t i o n was i d e n t i c a l

therm om eters were i n s e r t e d i n

in the

for a l l

tests.

The

t h e t o p box and t h e common

l e a d s a t t a c h e d t o th e p o t e n t i o m e t e r .

( A l l therm ocouples

were c a l i b r a t e d over the range of tem p era tu res e n c o u n te re d in t h i s accurate then

t e s t a g a i n s t a T a y l o r I n s t r u m e n t Company t h e r m o m e t e r , to the n e a r e s t t e n t h o f a d e g r e e .)

taken o f t h e s e

item s:

(1)

time o f d a y ,

o f to p therm om eter in upper b ox, therm om eter in up per box, b o t t o m bo x,

(5)

(9)

(3)

were r e q u ir e d t o take each s e t

tem perature

( 6 ) amps,

of therm om eter in (? ) v o l t s ,

pad t h e r m o c o u p l e s ,

( 1 1 ) and t h e r m o p i l e .

(2)

tem p era tu re o f bottom

tem perature

va ria c s e t t in g ,

p a n el therm ocouples, cou p les,

(4)

R e a d i n g s w e re

(10)

(8)

r u g t h e rm o ­

A p p r o x i m a t e l y two m i n u t e s of read in gs.

19 The h e a t i n p u t was

t n e n i n c r e a s e d and r e a d i n g s

a p p r o x im a t e ly e v e r y hour u n t i l heat

f o u r h o u rs had p a s s e d .

The

i n p u t was a g a i n i n c r e a s e d and t h e p r o c e s s was r e p e a t e d

u n t i l t h e r a n g e o f h e a t i n p u t had b e e n c o v e r e d . i n p u t range i s run.

taken

The h e a t

shown i n F i g u r e s 10 t h r o u g h 21 f o r a l l

tests

CHAPTER IV EXPERIMENTAL RESULTS Co m p a r i s o n o f h e a t d e l i v e r e d by r a d i a t i o n rugs t e s t e d .

F i g u r e 2 sh ows t h e h e a t d e l i v e r e d by r a d i a t i o n

fro m t h e r u g s t e s t e d p l o t t e d a g a i n s t t h e h e a tin g pan el.

It is

tem p erature o f the

e v i d e n t t h a t t h e r e was q u i t e a s p r e a d

of valu es;

however,

it

th at the v a lu es are r e p r e s e n t a t iv e .

is

felt

from t h e

At f i r s t

because o f the la r g e

number o f r e a d i n g s

i n s p e c t i o n o f F ig u re 2 the im p r e s s i o n might

be g i v e n t h a t r u g s a r e f a r i n f e r i o r t o b a r e p a n e l s ,

but i t

m ust be remembered t h a t t h e h e a t d e l i v e r e d shown i s

only

due t o

r a d ia tio n ,

o f the

t o t a l h e a t output o f a p a n el.

sents

w hich norm a lly a c c o u n ts

f o r 55 p e r c e n t

The d o t t e d l i n e

repre­

t h e h e a t d e l i v e r e d by r a d i a t i o n from •'panels" w i t h

su rroun din gs a t the

same mean r a d i a n t t e m p e r a t u r e a s w e r e e n 1 c o u n te r e d during t h i s t e s t . P a n els i s put in q u o tes because the r e fe r e n c e f a i l s used to arrive

to s p e c if y

a t the v a lu e s .

the p a r t i c u l a r type o f pan el I t was a s s u m e d t h a t

the v alu es

r e f e r r e d to bare c o n c r e te p a n e l s . The h e a t d e l i v e r e d by r a d i a t i o n was c a l c u l a t e d by equatin g i t storage

t o t h e h e a t g i v e n up by the t o p box t o t h e c o l d

room.

This s t a t e m e n t i s

r e p r e s e n t e d by t h e f o l l o w i n g

equation :

W i l l i a m H. S e v e r n s and J u l i a n R. F e l l o i v s , H e a t i n g , V e n t i l a t i n g , and A i r - C o n d i t i o n i n g F u n d a m e n t a l s , S e c o n d E d i t i o n (New York: John W i l e y and S o n s , I n c . , 19^ 9) > p* 3 ^ 0 .

'■/■fescr. Oczc.iVr->-~~r) B Y

j. ' r.--' '1 - 1

/Q t L lA T M U J .^ Q M

" ■ /& * $ &

7#£

-7 ^ i S T h s i a •

i-

\ . ^ i F ? U 3 ■ & >.. A - f \u < 3 \

A . '4-

l£3j- Hr^ Q N 0 m / n a jl /

o\:

:

... /o

ao

.;

' so . \

J ^ .T J D a a v s ^ Z L j b y J ^ s p /^ n c fiv i 'JBirc- *****• S o / nr . .

?’ '

!

• '

' i

-/■3 0 f r a :

‘

j

*2

' !

22 H eat d e l i v e r e d by r a d i a t i o n » H = UA(T-T0 ) w h er e H = h e a t t r a n s m it t e d p e r hour,

Btu.

U

— o v e r a ll c o e f f i c i e n t of heat tra n sm issio n .

A

= o u tsid e area

o f t o p box,s q .

T = in s id e a i r tem perature, Tq = o u t s i d e

a ir tem perature,

ft.

d e g r e e F. degree

F.

The o v e r a l l c o e f f i c i e n t o f h e a t t r a n s m i s s i o n i s

de­

f i n e d by the f o l l o w i n g e q u a t i o n : U a ______ 1______ ■ 1I X 1 fik fQ whe r e f i = i n s i d e c o m b in e d c o e f f i c i e n t o f r a d i a t i o n an d c o n v e c t i o n , Btu p e r h r . p e r s q . f t . p e r d e g r e e F. f 0 = o u t s i d e c o m b i n e d c o e f f i c i e n t o f r a d i a t i o n and c o n v e c t i o n , Btu p e r h r . p e r s q . f t . p e r d e g r e e F. x

s m aterial th ick n ess,

k

= t h e r m a l c o n d u c t i v i t y , Btu p e r h r . p e r s q . p e r d e g r e e F. p e r f t . o f t h i c k n e s s .

The t h e r m a l c o n d u c t i v i t y , value film

o f 0 . 0 2 8 Btu p e r h r .

in ch es. ft.

k,

f o r c e l o t e x was a s s i g n e d t h e 2 per f t . per F. p e r f t . and the

c o e f f i c i e n t s w ere a s s i g n e d th e a c c e p t e d v a l u e o f 1 . 6 5

for s t i l l

a ir con d ition s.

Since th e

2

t e s t s e t u p was l o c a t e d

in a c o ld sto ra g e

Aubrey I . Brown and S a l v a t o r e M. Marco, I n t r o d u c t l o n t o H e a t T r a n s f e r , (New York: M cG ra w -H ill Book C o . , 1 9 ^ 2 ) , p . 15*

room and s i n c e t h e

t e s t b o x was a i r t i g h t ,

i n t h e room and i n t h e t e s t g ib le;

th erefore,

the a i r v e l o c i t y

box was c o n s i d e r e d t o be n e g l i ­

t h e t y p e o f h e a t t r a n s m i s s i o n from t h e p a n e l

was c o n s i d e r e d t o be e s s e n t i a l l y

d i r e c t r a d i a t i o n w i t h an

a b s o l u t e minimum o f c o n v e c t i o n .

Of c o u r s e ,

the h e a t

by c o n d u c t i o n t o t h e u p p e r b o x i s n e g l i g i b l e b e c a u s e

transfer o f the

s m a l l a r e a o f p h y s i c a l c o n t a c t b e t w e e n t h e t o p box a n d r u g . It

is

true

th a t the rugs are o f d i f f e r e n t c o lo r s;

McAdams s t a t e s

t h a t the

"exact allow ance

however,

f o r the departure

o f s u r f a c e s from b l a c k o r i d e a l r a d i a t i n g c h a r a c t e r i s t i c s

is

in g e n e r a l too c o m p lic a te d f o r e n g in e e r in g u s e . T h e r e f o r e , no c o r r e c t i o n i s Pad A T 1s .

made f o r t h e d i f f e r e n t

F i g u r e s 3 t h r o u g h 6 show t h e p a d A T ' s

p lo t t e d again st panel su rface d e f i n e d as the pad s u r f a c e face

tem perature.

a tely effect

c o lo r s o f the ru g s.

The

tem perature.

The p a d A T i s

t e m p e r a t u r e m inus t h e p a n e l s u r ­

A T ’s f o r the pads were p l o t t e d s e p a r ­

f o r e a c h r u g so a c o m p a r i s o n c o u l d be made a s t o t h e o f t h e d i f f e r e n t r u g s on t h e t e m p e r a t u r e dr o p a c r o s s

the pad s. Rug A T 1s .

F igures

7,

8,

and 9 show t h e r u g

^ W i l l i a m H. McAdams, H e a t T r & n s m i s s i o n , McG-raw-Hill Book C o . , 1 9 /+ 2 ) , p . 5 9 .

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31 i s de­

‘The r u g

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The

/^ T 's fo r th e rugs were p l o t t e d s e p a r a t e l y

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T e m p e r a tu r e g r a d i e n t from p a n e l s u r f a c e t o r u g s u r f a c e . F i g u r e s 10 t h r o u g h 21 a r e a p l o t o f p a n e l ,

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