=N LS

Thermal Performance of Water

Heaters Using Alternative

Foam Blowing Agents

A. Hunter Fanney

Robert R. Zarr

Heat Transfer Group

National Institute ot Standards and Technology

November 10. 1998

NI

Acknowledgements

o BASF

- Michael Kurpu

* BradJfrd White

- F,'.ric L.anis

* National Institute tU Standards and Technology

- Keith Eberhart

- Jareb Keiav-Paprocki

- Stirt/le' 7. Vloreh(ise

* Pacific Northw'vest Laboratories

l - 'crrclt f reeman

Page 1

EE-RM-97-900 COMMENT 38SS
NISr

Overview

* Goal

* Scope

* Technical Approach

* Apparatus

* Experimental Results

+ Summarv

Goal

* Measure and Compare

- Thermal Conductivitv of Polvlirethane Fluums

Produced Using Blowing Agelnts

* HCFC - 14lb

*IF 0/4CO- "* HFC- 245fa

- Energy Factors of Water Heaters Insulated

With Resulting Polyurethane Foams

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EE-RM-97-900 COMMENT 38SS
NIST

Scope

* Blowving Atgennts

- l('f'(" I4'h I [ 

- flF'('- 24. ta f .

* Foar Block Specimensx ''

- 24' 2V x 2.6 inl (nominal)

* Water Heaters 1

- Residential

- Electric- .

- .o (;allon (nominal) ' ', .

N-IST

Technical Approach

* Water Heaters Insulated and Foam Blocks Produced

Siimu/ltaneousllV fr Each Blovwin- A-gent

- 4 f'oam' Block Specimens

- 4 Water Heater Specimens

* Insulation Production Dates and NIST Measurement Dates

Selected to Ensure t Equivalent Aging

ttowing Production t|hermal C(mductim it, Elapsed iime | laergy Factor Elapsd Timte

Atent Da euremen t ae l M r met Das (Days)

t , [4il, ! lt," q*i. , * 20 [ 's.l %- l q' If;,4

i . ...... I..... ,.......... . -

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EE-RM-97-900 COMMENT 38SS
-NIST

Experimental Apparatus

+ Thermal Conductivity Measurements

- NIST 1- meter Guarded Hot Plate

Vation's Standardfor Thermal

Conductivity Measurements

* ASTM Test Method C 177

* Energy Factor and Overall

Heat Loss Area Coefficient

Measurements

- VIST Water Heater Laboratory

* Supply Water Temperature Control

* Ambient Temperature Control

Fully Automated

* Infrared Imaging System

=NIST

Experimental Results

* Thermnal Conductivity

* Overall Heat-Loss-Area Coefficient

* Eergy t Factor

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EE-RM-97-900 COMMENT 38SS
NIST

Thermal Conductivity

Measurement Conditions

SPECIMENS_

M.iccrlal i rFh!kncs |Bu!k [,1el.< |

i2 HO/rCO. 2 S | .. ! )

TEST CONDITIONS

Hot 6S-rt7 - ! C;ii ouri r Amicn in- Arir

IF F 'F I 

1001) 7 5 3I |

120 o? ; ' 1

I'() j .D,. if) "I I 110 .; S i(), 7i :

Nt

Thermal Conductivity of

Polyurethane Foams

-z ;FCf41b

FC 24a -

-_- - - r -

'^ *w *,.-.„., ^ ^ * .

2 - - _ _ I , |

....-s. j g 5 _. 

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EE-RM-97-900 COMMENT 38SS
N LS

Thermal Conductivity of

Polyurethane Foams

H0/CO, Versus HCFC -141b

Ihcrnli Coulduclvity Btul n/h-t: -F UDltftrcnce

M1 c.n Tcilperatur lr 'F: HCFC-1 lb 1-O/CO: Percent

*3 3 0.146 0211 426

I3 0.218 425

113 S 1O.9 0.225 415

HFC-24Sfa VeYrus HCFC -14lb

Therilu l Cunlducrivity i Btu il/h t 'F) Dlifereilc

lMeasll rnmr:rature i 'F. HCFC-14 b IIFC-245fa Percent

3i 0 148 0.144 -2.9

I13 0153 0.149 -2.5

101s 0. Io5 0.153 -3.4

Ni

Overall Heat-Loss-Area Coefficient

I ^ ^J

--

0), Q,., Pa= , I

.2,1 = li, . T' l , -7- 1 ,'.))

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EE-RM-97-900 COMMENT 38SS
F N

Overall Heat-Loss-Area Coefficient

Setting the hot water load to zero and rearranging Eqs. 1. 2. and 3, yields

Qy,, is the electrical energy supplied to the water heater. Btu

Q,,, is the thermal energy removed/lost from the storage tank. Btu

Q,,we,, is the change in stored energy. Btu

Qh,, is the hot water load. Btu

Q., is the heat loss from the storage tank, Btu

7',,,v, is the average storage tank temperature i F)

71, is the ambient temperature 'F)

r is the test duration. (h)

and q is the heating element efficiency (0.98)

N LST

Overall Heat-Loss-Area Coefficients

Tank Number Blowing Agent Overall Heat-Loss-Area Coefficient (Btu/°Fhrl

-)24a2 !2-5 7 l1 *l6

I19242-1 2-.6-h | W.lt O i 16 l"242 12. 53 7 aiO i *lh0']

1a)242-12-6 2'42-12- S66 7* | Wrcr/'1:C, Walter,''O, 3j 1

192421--12 86 38 Wa1er/O, 36 10242 12 56 ' Water/C( O. : .l)

i1-12-1io-!2 1it. IlS

It 242 !' I1)t-.. | & 4i a .27 i

) 242 i].10o-q 1 ] lj', 1 - I 14):.{~.).c) ~ 44K-,

.* 1,27~ P g * 2o 

IPage 7I .C

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EE-RM-97-900 COMMENT 38SS
NI ST

Measured Heat-Loss-Area Coefficient

Versus Blowing Agent

Heat-Loss-Area Coefficient

'.:'. '-F .. Q l .2 hwl '- i

* i I 111: Q, st !S .98 0 1 !

i mE - - - - .98

= "' ' ' t ' (ItS

Page 8

EE-RM-97-900 COMMENT 38SS
NlST

Energy Factor Versus Overall

Heat-Loss-Area Coefficient

*32

0 - +- . .

I ! 3 83 *

-NLS,

Measured Energy Factor

Blowing Agent - HCFC - 141b

31ownq e HCFC ; ·

r,. ,,,., ..

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EE-RM-97-900 COMMENT 38SS
rNtST

Measured Energy Factor

Blowing Agent -H 20 /CO 2

Bloing Aent: N:0 CO_

I'C02

1 ,,i- ,, i. I 

= NlS

Measured Energy Factor

Blowing Agent - HFC 245fa

I alongiq A lge HFC. 21Sf

~I '''-* ~ ag 10----1

Page 10

EE-RM-97-900 COMMENT 38SS
Experimental Results

ENERGY FACTOR VERSUS BLOWING AGENT

N IST|

Average Energy Factor Versus

Blowing Agent

0.900

0 395 -

0.390

. II : 0 0887 0865 o0 88

81 *80 !

) 360

Page 1 1

EE-RM-97-900 COMMENT 38SS
NIST

Test Tank Infrared Image

I Test Tank Image Infrared 

I tR-1 E ;

Freeze

32.1

30.5

7728. L

27.3

25.7

24.1

1253941 .IMl C L"

98-05-20 12:07:40.74

Bradford Hhite Test Tank LS

_ \ £

-NIST

Test Tank Infrared Image

1IR-1

Freeze

29.4

28.3

27.2

26a.01

24.9

23.8

22.6

21.5-

771286822.I1116 L.

98-07-07 11:56:25.85

Bradford Uhite Test Tank

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EE-RM-97-900 COMMENT 38SS
Nlsr

Summary

+ Polyurethane Block Specimens and Water

Heaters Produced Using 3 Blowing Agents

- HCFC 141b

- 10/('0,

- HFC- 24'5a

* Thermal Conductivity Measurements

- HIO/C(O. Speciniens 43% (Greater Than IC'FC - 141b

- HFC - 245fa Specimens '3% Less Than Hi(FC - /4 lb

* Average Overall Heat-Loss-Area Coefficients

- l(CF( - 141b- .' /9Btu/' f hrr

- 11,0/CO, - 3.84 Btl/ F hr

- HFCA - 245fa - 3.22 Brta F hr

*NIST

Summary

* Energy Factor Not a Strong Function of

Overall Heat-Loss-Area Coefficient

- Doubling .UA Results in a 8% Decrease in EF

· Average Energy Factor Measurements

- fC1F( - 141b - ).Y87

- IH,(/('O, - 0.870

- 1GFC- 24fa -f - 4

+ Infrared Images Show Significant Thermal Shunts

- Tank Bottom/Top

- Drain Valve

- Heating Element Surrounds

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EE-RM-97-900 COMMENT 38SS