EPA-600/R-96-132
December. 1996
NEW CHEMICAL ALTERNATIVE FOR OZONE-DEPLETING SUBSTANCES;
HFC-245ca
By;
N, Dean Smith, Cynthia L. Gage, Evelyn Baskin, and Robert V. Hendriks
U. S. Environmental Protection Agency
National Risk Management Research Laboratory
Research Triangle Park, NC 27711
Prepared for:
U, S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
-------
NOT]CE
This document has been reviewed in accordance with
U.S. Environmental Protection Agency policyand
approved for publication. Mention of trade names
or comroerciaJ products does not constitute endorse-
ment or recommendation for use.
-------
FOREWORD
The U.S. Environmental Protection. Agency is charged by Congress with pro-
tecting the Nation's land, air, and water resources. Under a mandate of national
environmental laws, the Agency strives to formulate and implement actions lead-
ing to a compatible balance between human activities and the ability of natural
systems to support and nurture life. To meet this mandate, EPA's research
program is providing data and technical support for solving environmental pro-
blems today and building a science knowledge base necessary to manage our eco-
logical resources wisely, understand how pollutants affect our health, and pre-
vent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for
investigation of technological and management approaches for reducing risks
from threats to human health and the environment. The focus of the Laboratory's
research program is on methods for the prevention and control of pollution to air,
land, water, and subsurface resources; protection of water quality in public water
systems; remediation of contaminated sites and groundwater; and prevention and
control of indoor air pollution. The goal of this research effort is to catalyze
development and implementation of innovative, cost-effective environmental
technologies; develop scientific and engineering information needed by EPA to
support regulatory and policy decisions; and provide technical support and infor-
mation transfer to ensure effective implementation of environmental regulations
and strategies.
This publication has been produced as part of the Laboratory's strategic long-
term research plan. It is published and made available by EPA's Office of Re-
search and Development to assist the user community and to link researchers
with their clients.
E. Timothy Oppelt, Director
National Risk Management Research Laboratory
-------
ABSTRACT
Hydrofluorocarbons (HFCs) form a class of chemicals having the potential to replace
stratospheric ozone depleting substances such as chlorofluorocarbons (CFCs) and
hydrochlorofluorocarbons (HCFCs). This report gives results of a preliminary evaluation of a new
HFC (HFC-245ea or 1.1,2,2,3-pentafluoropropanc) as a possible alternative for CFC-11
(trichlorofluoromethane) and HCFC-123 (1,1, l,-trifluoro-2.2-dichloroethane) refrigerant for low-
pressure chillers and as a possible alternative for CFC-11 and HCFC-14lb (l-fluoro-1,1-
dichloroethanc) blowing agent for polyisocyanurate insulation foams. Evaluation tests included an
examination of its flammability, stability, thennophysical properties, lubricant miscibility, materials
compatibility, acute inhalation toxicity, and refrigeration performance. An azcotrope composed of
HFC-245ca and HFC-338mecq (1,1.1.2,3,4,4,4-octafluorobutane) was also examined from the
standpoint of reducing the flammability of HFC-245ca.
i'v
-------
TABLE OF CONTENTS
ABSTRACT
LIST OF FIGURES
LIST OF TABLES.
ABBREVIATIONS AND SYMBOLS
ACKNOWLEDGMENTS
1. INTRODUCTION
2. CONCLUSIONS
3. THERMOPHYSICAL AND APPLICATION PROPERTIES OF HFC-245ea 8
SYNTHESIS OF HFC-245ca 8
THERMOPHYSICAL PROPERTIES 8
ATMOSPHERIC LIFETIME 15
ACUTE INHALATION TOXICITY 16
FLAMMABILITY 16
HFC-245ca/LUBRICANT CHARACTERISTICS 22
STABILITY AND MATERIALS COMPATIBILITY 26
4. REFRIGERANT PERFORMANCE 34
CYCLE MODELING 34
HFC-245ca AS A CFC-11 REPLACEMENT IN CHILLERS 34
CENTRIFUGAL CHILLER ANALYSIS 40
COMPRESSOR CALORIMETRY RESULTS OF CENTRIFUGAL
CHILLER SIMULATION 41
Test Equipment and Method 41
Calorimeter Test Results 42
Page
V] i
.vi i i
i-X:':
~ V*
::x-
.,1
..6
v
-------
HFC-245ca AS A COMPONENT IN REFRIGERANT MIXTURES 50
Heat Pumps 50
Refrigerators/Freezers 50
5. INSULATION FOAM PERFORMANCE 63
EPA STUDY 63
INDUSTRY STUDY 64
6, REFERENCES 66
vi
-------
LIST OF FIGURES
Figure No. Page
1. Fourier-transform infrared spectrum of HFC-245ca 9
2. Gas chromatogram/mass spectrum of HFC-245ca 10
3. Flame propagation for HFC-245ca at 10 (%V) in air at varying relative humidity 18
4. HFC-245ea flammability VS relative humidity and concentration 19
5. HFC-245ca flammability VS concentration in air at 50% relative humidity 20
6. Elastomers volume data 28
7. Elastomers weight data 29
8. Elastomers swelling data 30
9. Elastomers hardness data 31
10. Superheat required to avoid wet compression for refrigerants with -k 37
11. Cycle efficiency with throttling and superheating/dry compression 38
12. Cycle volumetric capacity with throttling and superheating/dry compression 39
13. Cooling capacity of HFC-245ca relative to CFC-11 44
14. Compressor energy efficiency ratio of HFC-245ca relative to CFC-11 45
15. Compressor power input for HFC-245ca relative to CFC-11 46
16. Compressor isentropic energy efficiency of HFC-245ca relative to CFC-11 47
17. Compressor volumetric efficiency of HFC-245ca relative to CFC-11 48
18. Compression ratio of HFC-245ca relative to CFC-11 49
19. Lorentz-Meutzner refrigerator/freezer and instrumentation location 53
20. Performance of LM/RF using 750 Btu/hr compressor (T£z=-14.1 °C) 57
21. Better energy reduction performance of LM/RF using 750 Btu/hr compressor (Tf2=-14.1 °C)... 58
22. Normalized fresh food compartment temperature 60
23. Compressor run time comparison 61
vii
-------
LIST OF TABLES
Table No. Page
1. Chemical codes, formulas, and boiling points of the 37 new chemicals synthesized 3
2. Chemicals selected for further characterization 4
3. Thcrmophysical properties of liquid and vapor HFC-245ca 11
4. Lubricity test matrix sequence for wear tests and extreme pressure step test 24
5. HFC-245ca and POE-2 lubricity tests results 25
6. Compatibility test matrix 27
7. HFC-245ca/desiccant results 33
8. Properties of HFC-245ca and other CFC-11 alternatives 35
9. Centrifugal compressor characteristics at 4 °C evaporating and 40 °C condensing tempera-
tures 41
10. Heat pump analysis results 51
11. Modeled hydrofluoropropane-based zeotrope performance 51
12. CFC-12 refrigerator/freezer performance 54
13. HFC-134a refrigerator/freezer performance 54
14. HFC-245ca/HFC-134a refrigerator/freezer performance 55
15. HFC-245ca /HFC-152a refrigerator/freezer performance 55
16. HFC-245ca/HFC-245cb & HFC-245ca/HFC-227ea refrigerator/freezer performance 56
17. HFC-245ca/HC-270 refrigerator/freezer performance 56
vi i l
-------
ABBREVIATIONS AND SYMBOLS
C p heat capacity at constant pressure
C v heat capacity at constant volume
cap capillary tube length
COP coefficient of performance
EER energy efficiency ratio
GT glide temperature
Pc critical pressure
pc condensing pressure
pe evaporating pressure
PR pressure ratio
T b boiling point
Tc critical temperature
T wffi average fresh food evaporator inlet temperature
T evff0 average fresh food evaporator outlet temperature
T ^ average freezer evaporator temperature
T evfzi average freezer evaporator inlet temperature
T cvfzo average freezer evaporator outlet temperature
T if average fresh food compartment temperature
T& average freezer compartment temperature
VCR refrigeration volumetric capacity
"fx
-------
ACKNOWLEDGMENTS
Initial synthesis of HFC-245ca and determination of its thermophysical properties were
performed by Dairy] D. DcsMartcau and Adolph L. Beyerlein of Clemson University with the joint
sponsorship of the U. S. Environmental Protection Agency (EPA Cooperative Agreement CR-
815134) and the Electric Power Research Institute, Extended thermophysical property measurements
and determination of the rate constant for reaction of HFC-245ca with hydroxyl radical were
contributed by the National Institute of Standards and Technology under EPA sponsorship
(Interagency Agreement DW13935432). Krich Ratanaphruks, Michael W. Tufts, and Angelita S. Ng
of Acurex Environmental Corporation performed the llammability, thermal/chemical stability,
materials compatibility, lubricant irascibility, and lubricity evaluations under EPA Contracts 68-D0-
0141 and 68-D4-0005. Georgi Kazachki of Acurex Environmental Corporation was responsible for
the compressor calorimeter tests under EPA Contracts 68-DG-0141 and 68-D4-0005.
x
-------
1. INTRODUCTION
Fully halogcnated chloroiluorocarbons (CFCs) and their bromine-containing relatives
(halons) are recognized as primary contributors to depletion of the Earth's stratospheric ozone layer.
As early as 1978, the United States, on the basis of what was then largely theoretical evidence for
depiction of stratospheric ozone by CFCs, responded by promulgating restrictions on the use of CFCs
as propellants in aerosol products. At that time, aerosol propellants represented the single largest
commercial use of the CFCs. Only Sweden, Norway, and Canada joined the United States in
enacting measures to reduce CFC emissions at that time.
In the mid-1980's, as scientific evidence confirming stratospheric ozone depletion mounted, the
U. S. Environmental Protection Agency (EPA) began considering additional regulatory restrictions on
the use of CFCs and halons by weighing the environmental benefits against the economic and societal
consequences of such action. In the course of this study, it became apparent that few, if any,
alternative chemicals were readily available or had been proven applicable to the numerous CFC and
halon uses which had grown dramatically in the short time span following the 1978 CFC aerosol ban.
In the spring of 1987, the EPA convened a panel of international experts to assess the
likelihood of finding suitable alternative chemicals. Compounds in which one or more of the chlorine
or bromine atoms of the CFCs and halons were replaced by hydrogen atoms appeared to offer a high
probability of serving as successful alternatives. It was noted that the presence of hydrogen in the
molecules would increase the probability that the molecules would degrade in the lower atmosphere
and be dissipated before reaching the ozone layer. However, it was also noted that replacing halogen
atoms with hydrogen atoms could lead to undesirable flammability, toxicity, and/or reduced efficacy
of the compounds in certain applications. Among the findings of the expert panel was the conclusion
that governments should sponsor research to enhance knowledge of chemical substitutes, particularly
research into those chemicals that were not already under active consideration by chemical companies
(Nelson, 1988).
1
-------
Shortly after the landmark Montreal Protocol on Substances that Deplete the Ozone Laver
was negotiated in September, 1987 (UNEP, 1987), the EPA's Air and Energy Engineering Research
Laboratory (AEERL) * initiated a search for new chemical alternatives, This effort was undertaken
to try to provide an expanded set of candidate alternatives in the event that the few chemicals which
had then been proposed as alternatives fell short of expectations.
In 1988, AEERL and the Electric Power Research Institute (EPRI) formed a cooperative
project with the chemistry departments of Clemson University and The University of Tennessee
(Knoxville) to synthesize a number of partially fluorinated propanes and butanes and fluoroethers
which, on the basis of molecular structure and anticipated boiling points, were thought to be possible
CFC or halon alternatives. These compounds also possessed structural features believed to enhance
degradation of the compounds in the troposphere. Over a 3-year period, 37 compounds were
prepared of sufficient stability and in sufficient yield and purity to obtain a limited set of relevant
property measurements. Of the 37 chemicals synthesized, 15 were hydrofluoropropanes and butanes
(HFCs), 8 were hydrofluoroethers (HFEs), 5 were fully fluorinated ethers (FEs), and 9 were
hydrochlorofluoropropanes (HCFCs). These compounds and their normal boiling points are listed in
Table 1.
AEERL selected for further study 11 of the 37 synthesized chemicals whose measured boiling
points and critical temperatures most closely matched those of CFCs-11, -12, -114, and -115 or
which might form mixtures having desirable properties. Alternatives for CFC-113, widely used as a
solvent, were not emphasized since a number of chemicals and technologies appeared to already exist
or be emerging to replace this compound. Also, compounds which possessed chlorine (HCFCs) were
ruled out for further evaluation since it was becoming clear that such compounds had non-zero ozone
depletion potentials and would also be subject to future phaseout. Table 2 presents the 12
compounds selected by AEERL for further examination.
Recently redesignated the Air Pollution Prevention and Control Division of the National Risk
Management Research Laboratory, Research Triangle Park (NRMRL - RTP), NC.
2
-------
Table 1. Chemical codes, formulas, and boiling points of the 37 new chemicals synthesized.
Chemical Code
Chemical Formula
Th(°C)
HFC-227ca
CF3-CF2-CF2H
-16.3
HFC-227ea
CF3-CHF-CF3
-18.3
HFC-236ca
CHF2-CF2-CHF2
12.6
HFC-236cb
CF3-CF2-CFH2
- 1.4
' HFC-236ea
CF3-CHF-CF2H
-6.5
HFC-236fa
CF3-CH2-CF3
-1.1
HFC-245ca
CF2H-CF2-CFH2
24.9
HFC-245cb
cf3-cf2-ch3
-18.3
HFC-245fa
CF3-CH2-CF2H
15.3
HFC-254cb
cf2h-cf2-ch3
-0.8
HFC-329ccb
• CF3-CF2-CF2-CF2H
15.1
HFC-338cca
CHF2-CF2-CF2-CH2F
42.5
HFC-338mccq
CF3-CF2-CF2-CFH2
27.8
HFC-338eea
CF3-CHF-CHF-CF3
25.4
HFC-347ccd
CF3-CF2-CF2-CH3
15.1
HCFC-225ba
CF3-CFC1-CFHC1
51.9
HCFC-225da
CF3-CHC1-CF2C1
50.8
HCFC-226da
CF3-CHC1-CF3
14.1
HCFC-226ea
CF3-CHF-CF2C1
17,1
HCFC-234da
CF3-CHC1-CFHCI
70.1
HCFC-235ca
CF3-CF2-CH2C1
28.1
HCFC-243da
CF3-CHC1-CH2C1
76.7
HCFC-244ea
CF2H-CF2-CH2Ci
54.8
cy-HCFC-326
cy-(CF2)3-CHCl-
38.1
(continued)
3
-------
Table 1. Continued
Chemical Code
Chemical Formula
ThPC)
HFE-125
cf3-o-cf2h
-34.6
HFE-134
CF2H-0-CF2H
4.7
HFE-143
CF2H-0-CFH2
29.9d
HFE-143a
CF-j-O-CH*
\s X *% V/ X
-24.1
HFE-227ca
cf3-o-cf2-cf2h
-3.1
HFF.-I24B!
CF2H-0-CF2Br
24.5
FE-115B1
CF3-0-CF2Br
-5.4
FE-116
CF3-O-CF3
-58.7
FEE-218
CF 3-0-CF2 -O-CF 3
-9.8
cy-HFE-225
cy-CHF-CF2-0-CF2-
34
cy-HFE-234
cy-CH2-CF2-0-CF2-
21.2
cy-FE-216
cy-Cr2-CF2-0-CF2-
-28.2
cy-FEE-216
cy-CF2-0-CF2-0-CF2-
-22.1
Note: Chemical codes for the ether compounds have not been standardized. The listed codes
are AEERL designations, "d" = decomposes.
Table 2. Chemicals selected for further characterization
Alternatives
Chemical
Chemical
Chemical
for:
Code
Formula
Name
CFC-1 l/HCFC-123
HFC-245ca
CF7H-CF2-CFH?
1,1,2,2,3-pentafluoropropane
HFC-245fa
CF3-CH2-CF2II
1,1,1,3,3-pentafluoropropane
HFC-338mccq
cf3-cf2-cf2-cfh2
1,1,1,2,2,3,3,4-octafluorabutane
CFC-12
HFC-227ca
CFvCFvCF-jH
1,1,1,2.2,3,3 -hepta fluoropropane
HFC-227ea
CF3-CHF-CF3
1,1,1,2,3,3,3 -hepta tluoropropane
HFC-245cb
CF3-CF2-CH3
1,1,1,2,2-pentafluoropropane
HFE-143a
CF3-0-CH3
l.l ,1-trifluoro-dimethyl ether
CFC-114
HFC-236cb
CFvCFn-CFIh
1,1,1,2,2,3-hexafluoropropane
HFC-236ea
CF3-CFH-CF2H
1,1,1,2,3,3-hexatluoropropane
HFC-236fa
cf3-ch2-cf3
1,1,1,3,3,3-hexafluoropropane
HFC-254cb
cf2h-cf2-ch3
1,1,2,2-tetrafluoropropane
CFC-115
HFE-125
CFVO-CF?!!
pentafluoro-dimethyl ether
4
-------
Extended evaluation of these 11 candidates was undertaken by AEERL with emphasis on
their potential use as refrigerants and as blowing agents for insulation foams. Expanded evaluation
included determination of atmospheric lifetimes, acute inhalation toxicities, chemical stabilities,
material compatibilities, vapor thermal conductivities, lubricant miseibilities, and refrigeration
performance,
This report summarizes results obtained for one of the candidates, HFC-245ca (1,1.2,2,3-
pentafluoropropane), as a potential alternative refrigerant for CFC-11 and HCFC-123 in low
pressure chillers and as a blowing agent for production of polyisocyanurate and polyurethane foam.
5
-------
2. CONCLUSIONS
HFC-245ca has been shown to be a potentially viable alternative for CFC-11 and HCFC-123
for use as a refrigerant in low-pressure chillers. Thermophysical properties of HFC-245ca compare
favorably with those of CFC-11, and modeled performance as a refrigerant in low-pressure chillers
indicates a loss of efficiency of 3 to 4 percent relative to CFC-11 (1 to 2 percent relative to HCFC-
123). Modeled performance has been confirmed by laboratory tests in a compressor calorimeter
operating under chiller conditions.
Five zeotropic mixtures containing HFC-245ca were selected for performance tests in home
refrigerators-freezers. Two mixtures predicted to outperform HFC-134a (HFC-245ca/HFC-134 and
HFC-245ca/HFC-152a) performed comparably to it , and a third (HFC-245ca/HC-270) performed
as predicted. HFC-245ca/HC-270 outperformed all zeotropic mixtures and HFC-134a with energy
consumption reductions approximately 19.2 percent in comparison to HFC-134a. The lower
volumetric capacity of these zeotropic mixtures in comparison to HFC-134a suggests that a larger
compressor would be required to deliver the same capacity as HFC-134a.
HFC-245ea contains no chlorine or bromine and therefore has zero potential to deplete
stratospheric ozone. Its measured reaction rate with hydroxyl radical is 9.1 x 10"^ cnp molecule"*
sec""* which translates to an estimated atmospheric lifetime of 5.8 years. This is generally considered
to be an acceptable atmospheric lifetime from a global warming perspective.
Limited inhalation toxicity testing with the compound has been completed. In these tests, 2
populations of 10 rats each were exposed for 4 hours to HFC-245ca in air at nominal concentrations
of 1000 and 50,000 ppm, respectively. All animals survived the tests and exhibited no significant
adverse effects during the exposure period or during the succeeding 14-day observation period. Post-
mortem examination of the animals indicated no effects. Although these toxicity tests were limited in
6
-------
scope, the results are encouraging and suggest that HFC-245ca may be less toxic than CFC-11 which
has an LCjgfrat) of 27,000 ppm.
Sealed tube stability and materials compatibility tests with HFC-245ca, both in the presence
and absence of a polyolester lubricant, show the compound to be thermally and hydrolytically stable
and compatible with many common engineering materials. Compatibility tests performed by the EPA
were confirmed by independent tests performed by the Trane Company (Doerr and Kujak, 1993;
Doerr and Waite, 1995), Among the elastomeric materials tested by the EPA, E-70 or EPDM (a
copolymer of ethylene, propylene, and dicyclopentadiene) was found to work best in the presence of
HFC-245ca alone. Natural rubber and a nitrile polypropylene polymer worked best with combined
HFC-245ca and polyolester lubricant.
HFC-245ca was found to be completely miscible with two different polyolester lubricants over
the temperature range of -30 to + 125 °C Lubricity tests indicated that the chemical is compatible
with this type of lubricant and that the presence of the refrigerant in the oil improved the wear
performance of the oil.
One potential disadvantage of HFC-245ca is its low to moderate flammability. An interesting
aspect of the chemical's flammability is its sensitivity to the moisture content of the HFC-245ca/air
mixture. At relative humidities below approximately 20 percent at room temperature, the mixture is
nonflammable while at higher humidities and temperatures the chemical becomes increasingly
flammable. A thorough evaluation of the safety risks associated with the compound as a refrigerant
or blowing agent and ways to mitigate such risks have yet to be accomplished,
HFC-245cahas a measured vapor thermal conductivity of 0.0137 Wm"'K"' at 300 K. This is
16 times greater than the vapor thermal conductivity of CFC-11. Laboratory studies have shown
that HFC-245ca should be easy to process using conventional foaming equipment but that changes in
foam formulations may be required to approach equivalent insulation and mechanical characteristics
compared to CFC-11 blown foams.
7
-------
3, THERMOPHYSICAL AND APPLICATION PROPERTIES OF HFC-245ca
SYNTHESIS OF HFC-245ca
HFC-245ca was prepared in laboratory- quantities (ca, 100 g) by reaction of SF4 with
commercially available 1,1,2,2-tetrafluoropropanol at 100 °C, according to the generalized reaction
below. A 20 percent excess of SF4 was found to be necessary to obtain a good (85 percent) yield.
SF4
hcf2 - cf2 - CH2OH > HCF2 - cf2 - CH2F
100 °c
Product obtained from this reaction was characterized by gas chromatography (GC), infrared
(IR) spectrophotometry, mass spectrometry (MS), and '^F and *H nuclear magnetic resonance
(NMR) spectrometry. Purity of the HFC-245ea thus prepared was 99.9 percent. This laboratory-
scale synthesis effort and preliminary thermophysical property measurements were performed by
Clemson University under joint sponsorship of the EPA and EPRI
Kilogram quantities of the compound needed for toxicity, performance, and other tests were
procured from PCR. Inc. in Gainesville, FL, Individual lots of the compound delivered to AEERL
for testing were subjected upon receipt to GC/IR/MS purity assay and found to be 99.9 percent pure.
Figures 1 and 2 present Fourier transform IR and mass spectra for HFC-245ca, respectively.
THERMOPHYSICAL PROPERTIES
Table 3 gives thermophysical property data for HFC-245ca as determined by the National
Institute of Standards and Technology (NIST). The Carnahan-Starling-DeSantis (CSD) equation of
state was used to correlate measured p-v-t data and was combined with ideal gas heat capacity
8
-------
Wavenumber (cm-1)
Figure 1. Fourier-transform infrared spectrum of HFC-245ca
9
-------
KBuHHaEce
1.2e*-07
l
2.00 4.00 6,00 8.00 10. 00 12^00 14.00 16.00 18.00
teuudance
Scan 1096 (8.505 ttin) : 245CA5A.D
5CL
Figure 2. Gas chromatogram/mass spectrum of HFC-245ca
10
-------
Table 3. Thermophysical properties of liquid and vapor HFC-245ca
Tempe-
rature
(°C)
Pressure
(kPa)
Density
(kg/ro3)
Volume
(m3/kg)
Entropy
(kJ/kg K)
Enthalpy
(kJ/kg K)
Cv
(kJ/kg K)
Cp
(kJ/kg K)
vapor
liquid
vapor
liquid
vapor
liquid
vapor
liquid
vapor
liquid
vapor
-30
6.81
0.4537
1519
2.2040
0.0467
0.9815
11.1
238.4
1.022
0.6730
1.130
0.7361
-25
9.23
0.6032
1507
1.6580
0.0699
0.9775
16.8
242.1
1.039
0.6877
1.146
0.7511
-20
12.33
0.7913
1496
1.2640
0.0929
0.9745
22.6
245.8
1.056
0.7022
1.163
0.7660
-15
16.26
1.025
1484
0.9757
0.1158
0.9722
28.4
249.5
1.072
0.7165
1.179
0.7807
-10
21.17
1.312
1472
0.7622
0.1386
0.9706
34.4
253.3
1.088
0.7305
1.195
0.7953
-5
27.25
1.661
1460
0.6020
0.1612
0.9697
40.4
257.2
1.104
0.7444
1.211
0.8099
0
34.69
2.082
1448
0.4803
0.1837
0.9693
46.5
261.1
1.120
0.7580
1.227
0.8243
5
43.70
2.585
1436
0.3869
0.2061
0.9696
52.7
265.0
1.135
0.7715
1.243
0.8387
10
54.54
3.180
1424
0.3144
0.2284
0.9703
58.9
269.0
1.150
0.7847
1.259
0.8531
15
67.44
3.881
1412
0.2577
0.2506
0.9714
65.3
273.0
1.164
0.7978
1.275
0.8674
18
76.29
4.357
1405
0.2295
0.2638
0.9723
69.1
275.4
1.173
0.8055
1.284
0.8760
20
82.68
4.700
1400
0.2128
0.2726
0.973
71.7
277.0
1.178
0.8107
1.290
0.8818
22
89.50
5.063
1395
0.1975
0.2814
0.9737
74.3
278.6
1.184
0.8158
1.296
0.8876
24
96.76
5.449
1390
0.1835
0.2902
0.9745
76.9
280.3
1.190
0.8209
1.302
0.8933
26
104.5
5.857
1385
0.1707
0.2989
0.9754
79.5
281.9
1.195
0.8259
1.308
0.8991
28
112.7
6.290
1380
0.1590
0.3076
0.9763
82.1
283.5
1.200
0.8309
1.315
0.9049
30
121.4
6.747
1375
0.1482
0.3163
0.9772
84.8
285.1
1.206
0.8359
1.321
0.9107
32
130.6
7.231
1370
0.1383
0.3250
0.9782
87.4
286.7
1.211
0.8409
1.327
0.9166
34
140.4
7.742
1364
0.1292
0.3337
0.9793
90.1
288.4
1.216
0.8459
1.333
0.9224
36
150.7
8.281
1359
0.1208
0.3424
0.9804
92.8
290.0
1.221
0.8508
1.339
0.9283
38
161.7
8.849
1354
0.1130
0.3510
0.9815
95.4
291.6
1.227
0.8557
1.345
0.9343
40
173.2
9.448
1349
0.1058
0.3596
0.9827
98.1
293.2
1.232
0.8606
1.351
0.9402
42
185.4
10.08
1344
0.0992
0.3682
0.9839
100.9
294.9
1.237
0.8654
1.357
0.9462
44
198.2
10.74
1338
0.0931
0.3768
0.9851
103.6
296.5
1.242
0.8703
1.363
0.9522
46
211.7
11.44
1333
0.0874
0.3854
0.9864
106.3
298.1
1.247
0.8751
1.369
0.9583
(continued)
-------
Table 3. Continued
Tempe-
rature
(°C)
Pressure
(kPa)
Density
(kg/m3)
Volume
(m3 / kg)
Entropy
(kJ/kgK)
Enthalpy
(hJ/kgK)
Cv
(kJ/kgK)
Cp
(fcJ/kgK)
vapor
liquid
vapor
liquid
vapor
liquid
vapor
liquid
vapor
liquid
vapor
50
240.9
12.94
1322
0.0773
0.4025
0.989
111.8
301.4
1.256
0.8846
1.382
0.9706
55
281.7
15.04
1309
0.0665
0.4237
0.9925
118.8
305.4
1.268
0.8965
1.397
0.9862
60
327.6
17.40
1295
0.0575
0.4449
0.9961
125.8
309.4
1.279
0.9082
1.412
1.0020
65
379.1
20.06
1281
0.0499
0.4659
0.9998
132.9
313.4
1.290
0.9199
1.428
1.0190
70
436.5
23.02
1266
0.0434
0.4869
1.004
140.1
317.4
1.301
0.9315
1.443
1.0360
75
500.4
26.34
1251
0.0380
0.5078
1.007
147.4
321.3
1.311
0.9430
1.459
1.0540
80
571.1
30.04
1236
0.0333
0.5285
1.011
154.7
325.2
1.320
0.9545
1.476
1.0730
85
649.2
34.15
1221
0.0293
0.5492
1.015
162.1
329.1
1.330
0.9659
1.492
1.0930
90
735.1
38.72
1205
0.0258
0.5698
1.019
169.6
332.9
1.338
0.9774
1.510
1.1140
95
829.2
43.80
1188
0.0228
0.5904
1.023
177.2
336.6
1.347
0.9888
1.528
1.1360
100
932.1
49.43
1171
0.0202
0.6108
1.027
184.9
340.2
1.355
1.0000
1.547
1.1610
105
1044
55.67
1154
0.0180
0.6312
1.031
192.6
343.8
1.362
1.0120
1.567
1.1870
110
1166
62.59
1135
0.0160
0.6515
1.035
200.5
347.3
1.369
1.0240
1.589
1.2170
115
1298
70.27
1116
0.0142
0.6718
1.038
208.4
350.6
1.376
1.0350
1.613
1.2490
120
1441
78.78
1097
0.0127
0.6921
1.042
216.5
353.9
1.381
1.0470
1.640
1.2850
125
1595
88.23
1076
0.0113
0.7123
1.045
224.6
357.0
1.387
1.0600
1.669
1.3260
130
1761
98.75
1055
0.0101
0.7326
1.048
232.9
360.0
1.391
1.0720
1.704
1.3740
135
1939
110.5
1032
0.0091
0.7528
1.051
241.3
362.9
1.395
1.0850
1.743
1.4290
140
2129
123,6
1008
0.0081
0.7731
1.053
249.8
365.5
1.399
1.0980
1.791
1.4940
145
2333
138.3
982.9
0.0072
0.7936
1.055
258.5
368.0
1.401
1.1120
1.849
1.5740
150
2551
154.8
955.9
0.0065
0.8141
1.057
267.4
370.3
1.403
1.1270
1.923
1.6730
155
2783
173.6
926.7
0.0058
0.8349
1.059
276.4
372.2
1.403
1.1420
2.020
1.8010
-------
information to define the set of internally consistent thermodynamic functions shown in Table 3.
CSD equation of state is of the form:
The
PV/RT = 1 fy+y2 -y3/(l-y)3 - a/RT(V+b)
where P = pressure, V = volume, R = universal gas constant, T = temperature, and
y = b/4V,
a = a0exp(ajT+a2^) kJ m^/kmol,2
b = (bo+bjT+l^T^)
The function used to generate the data for ideal gas heat capacity in Table 3 was:
Cp = (c0 + C1T+C2T2) kJ/(kmol K)
CSD parameters required to generate the complete set of thermodynamic properties are:
a
-------
ranged in pressure from 101,9 to 1400.6 kPa, corresponding to a temperature range of 298 to 391 K.
Again, the uncertainty in pressure and temperature was ±0,5 kPa and +0.01 K. respectively. The two
data sets were correlated with:
In P/Pc = Tc/T[A]t +A2t15 + A3t2-5 +A4t5]
Aj = -7.8455350 Tc = 447.570 K
A2 = 2.1265273 Pc = 3925.232 kPa
A3 = -3.4657037 t = 1-T/TC
A4 = -2.3076120
T = absolute temperature, K P = vapor pressure at temperature (T). kPa
Saturated liquid densities were generated by extrapolating isotherms of compressed liquid to
the vapor pressure determined by the above equation. Saturated vapor densities were deduced from
the measured virial equation of state and measured vapor pressures. Speed of sound measurements
were determined using a cylindrical resonator in the temperature range 311 to 400 K. Transport
properties used in the analysis of the acoustic data were estimated from functional group methods
Ideal gas heat capacity data generated from the acoustic data are represented by:
Cp /R = ag + ajt + a2t^
T-273.15K = Celsius temperature
13.212 ± 0.170
(0.0432 ±0.0044) 0Cl
-(7.4±2.4)xl0-5 0C'2
8.314471 J/(Kmol) = universal gas constant
The reader is referred to the NIST Technical Note 1226 (Morrison and McLinden, 1986) for a
more complete explanation of the CSD equation of state. A complete set of thermophysieal
where
t
ao
ai
a2
R
14
-------
properties for HFC-245ca is also available from the N1ST database REFPROP Version 5.0 (NIST,
1995).
ATMOSPHERIC LIFETIME
Compounds such as HFC-245ca which do not contain chlorine or bromine atoms are not
capable of destroying stratospheric ozone. However, the presence of carbon-fluorine bonds in the
molecule can render the chemical a strong absorber of infrared radiation. Therefore, it is of interest
to ascertain the atmospheric lifetime of the compound to gauge its global warming potential (GWP).
Carbon-hydrogen (C-H) bonds in the molecule subject the chemical to degradation by reaction with
atmospheric hydroxyl (OH) radicals (Prin, 1995), Therefore, atmospheric stability of a chemical
containing C-H bonds is usually determined by measuring the reaction rate of the chemical with OH
radical. Atmospheric lifetimes are then calculated by comparing the measured rate constant with that
of methyl chloroform whose atmospheric lifetime is independently known. Kinetic experiments for
the HFC-245ca/OH reaction were performed for the EPA by NIST using the technique of resonance
fluorescence spectrometry.
By this method, the reaction rate constant for abstraction of a hydrogen atom from HFC-245ca
with OH was determined to be 7.1xl0"15 cm3 molecule"1 see"1 at 277 K. Confirmatory
determinations were subsequently made by other researchers and a consensus value for the HFC-
245ca/OH rate constant of 9.1x10'^ cm^ molecule"' see"* and a corresponding atmospheric
lifetime of 7.7 years was established by the NASA (National Aeronautics and Space Administration)
Panel for Data Evaluation (NASA, 1992). More recently, the atmospheric lifetime of methyl
chloroflorm was revised downward (Prin, et al, 1995) yielding in turn a revised atmospheric lifetime
for HFC-245ea of 5.8 years. A global warming potential for the compound corresponding to a 500-
year horizon is estimated to be 190 relative to carbon dioxide which is assigned a 500-year GWP of
1.
15
-------
ACUTE INHALATION TOXICITY
HFC-245ca was administered to two groups of 10 Sprague-Dawley rats (5/sex) for 4 hours at
two different concentrations in air (993 and 50,000 ppm) in accordance with a protocol established
by the EPA's Office of Toxic Substances (EPA, 1985).
Physical observations for abnormal signs of behavior were conducted on all animals as a group
at 15 minute intervals during the first hour of exposure and hourly for the remainder of the exposure.
All animals received detailed physical observations just prior to exposure, upon removal from the
chamber, hourly for 2 hours post-exposure, and once daily thereafter. Body weight measurements
were obtained just prior to exposure on Day 1 and Days 2, 5, 8, and 15, After a 14-day post-
exposure observation period, all animals were sacrificed and complete gross postmortem
examinations performed.
All animals survived the exposure and the 14-day post-exposure observation period at both
concentrations. Signs of treatment were minimal during the exposure and subsequent recovery period.
Also, a minimal effect upon body weight was produced by treatment. Gross postmortem
observations were considered unremarkable. From these results it is concluded that the LCsgCrat) for
HFC-245ca is greater than 50,000 ppm. It is noted that the LC5o(rat) for CFC-11 is 27,000 ppm,
suggesting that HFC-245ca may be less toxic than CFC-11.
FLAMM ABILITY
Flammability of HFC-245ca was evaluated by means of the American Society for Testing and
Materials (ASTM) E681-94 standard method for determination of flammability limits (ASTM,
1994). Tests were conducted at room temperature using a 5-liter glass test vessel and a 0.1 second
AC spark generated by a 15 kV, 30 mA power supply as the ignition source. Accurate humidity
control was achieved by first injecting known quantities of deionized water into the evacuated 5-liter
flask with a microsyringe followed by introduction of the HFC and dry (0.1 percent relative humidity)
air in that order.
-------
Pressure increases resulting from vaporization of the water injected into the evacuated flask
always fell short of values predicted from ideal gas law calculations. This discrepancy increased as
the amount of injected water increased suggesting that some adsorption of water on the electrodes and
flask walls was occurring which prevented all of the water from vaporizing. Therefore, measurement
of the relative humidity of the HFC-245ca/air mixture was necessary. Relative humidities in the flask
following introduction of water were measured with a humidity probe accurate to within 2 percent
over the range of 0 to 90 percent relative humidity. These relative humidity readings were found to
correlate well with pressure readings obtained via a pressure transducer inserted into the flask. Once
it was established that accurate relative humidity values could be obtained via the pressure
transducer, the transducer was used for acquiring this measurement.
In this evaluation it was discovered that HFC-245ca was moderately flammable at 300 K and
101.3 kPa (1 aim) pressure, and that the flammability limits were remarkably dependent on the
moisture content of the HFC-245ca/air mixture. The effect of moisture on the flammability of HFC-
245ca can be seen from Figure 3 which plots the extent of flame propagation (as "flame propagation
rank") in the flask versus the relative humidity of a mixture of 10 volume percent HFC-245ca in air.
A flame propagation rank of 3.0 denotes the condition at which the chemical just reached the
point of being flammable according to the ASTM definition. As evident from Figure 3, HFC-245ca
at 10 volume percent in air would be considered nonflammable at 300 K and 101.3 kPa when the
relative humidity of the mixture is less than approximately 21 percent The compound would,
however, be flammable at relative humidities above 21 percent.
As the concentration of HFC-245ca in air varies, so does the minimum relative humidity
required to render the HFC flammable. Figure 4 is a plot of experimental data showing the minimum
humidity required for HFC-245ea to be flammable at 300 K and 101.3 kPa as a function of HFC-
245ca concentration. This plot indicates that the lower and upper flammability limits (LFL and UFL)
change with relative humidity of the test mixture. At 30 percent relative humidity, the flammable
range is 7.7 to 13.0 volume percent HFC-245ca, while at 40 percent relative humidity the flammable
-------
' ' ' ¦ 1 '
0 10 20 30 40 50 60 70
Relative Humidity (%)
Figure 3. Flame propagation VS relative humidity for HFC-245ca @ 10.0 (%V) in air
-------
55
50
45
£» 40
-S
•m
a ..
3 35
X
a>
*5 30
J3
C*
25
20
15
Not Flammable
Flammable
¦
10 12 14
HFC-245ca Concentration (Volume %)
16
18
Figure 4. HFC-245ca flammability VS relative humidity and concentration
-------
a
a
E
10 12 14
HFC-245ca Concentration (Volume %)
16
18
Figure 5. HFC-245ca flammability VS concentration in air @ 50% relative humidity
-------
range broadens to 6 8 to 15.1 volume percent HFC-245ca. The LFL is considered accurate to +0.9
volume percent, and the UFL is considered accurate to ±1.8 volume percent. Figure 4 indicates that
HFC-245ca should be nonflammable at 300 K and relative humidities below 21 percent in agreement
with the results portrayed in Figure 3.
Figure 5 indicates that at 50 percent relative humidity, 300 K. and 101.3 kPa, the
flammability of HFC-245ca as measured by the extent of flame propagation observed in the test
vessel is greatest at a concentration of approximately 9 volume percent. This is nearly the same
concentration of HFC-245ca which required the lowest relative humidity to render the chemical
nonflammable (10 volume percent). The 1 percent concentration difference between the minimum in
Figure 4 and the maximum in Figure 5 could be due to the subjectivity involved in the determination
of flame propagation rank. Hie good agreement of the results of these two experiments underscores
the close relationship of flammability and moisture content of the test mixture,
Ail explanation of the humidity effect was first sought in the thermochemistry of the HFC-
245ca/air system. Two overall combustion reactions are possible as denoted by:
C3H3F5 + 5/202 + H2O —> 3CC>2 + 5HF Reaction 1
C3H3F5 + 5/20j —> 2CO2 + 3HF + COF2 Reaction 2
Free energies and enthalpies of combustion for each of the two possible combustion reactions
were calculated using values of Gibbs free energy and enthalpy of formation for HFC-245ca (-1002 J
mol"1 K"* and -1088 J moH K"1, respectively) estimated by the group additivity approach advanced
by Domalski and Hearing (1993). For Reaction 1, the calculated free energy of combustion is -1320
kJ/mol and the combustion enthalpy is -1194 kJ/mol. For Reaction 2, the calculated free energy of
combustion is -1207 kJ/mol and the combustion enthalpy is -1115 kJ/mol. These calculated values
apply to the conditions of 298.15 K and 101.3 kPa with all reactants and products in the vapor state.
Negative values for the free energies and enthalpies indicate that the reactions are thermodynamically
21
-------
spontaneous and exothermic, respectively. The more negative combustion free energy of Reaction 1
indicates that this is the more thermodynamically favored of the two possible reactions Therefore,
the presence of water in an HFC-245ca/air mixture will enable the more favored and exothermic
reaction to occur. As the moisture content of the HFC-245ea/air mixture decreases, Reaction 2
occurs to a greater extent relative to Reaction 1,
It can be shown that the increment in thermal energy released by Reaction 1 compared to
Reaction 2 is more than offset by the reduction in thermal energy released caused by water replacing
oxygen molecules in the 5-liter flask used in the ASTM flammability tests when the concentration of
HFC-245ca and total pressure in the flask are kept constant. This suggests that the observed
dependence of flammability on humidity is controlled by factors other than thermochemistry alone
and that the presence of water vapor probably alters the reaction kinetics in such a way as to promote
combustion.
It was reported at the 1994 .International Conference on CFC and Halon Alternatives
(Beyerlein et aL 1994) that HFC-245ca and HFC-338mccq (1,1,1,2,2,3,3,4-octafluorobutane) form
an azeotrope. The composition of the azeotrope at 298 K is 63.8 volume percent HFC-245ca and it
shifts to 77 8 volume percent HFC-245ea at 671 K. It was of interest to see how the flammability of
the azeotrope compared to the flammability of HFC-245ca alone since the HFC-338mecq by itself is
not flammable. Indeed, the 63.8:36.2 azeotrope was found to be not flammable at room temperature
and relative humidities of 50 to 65 percent. However, the mixture was flammable at 100 °C.
HFC-245ca/LUBRICANT CHARACTERISTICS
Sealed tube miscibility experiments were conducted utilizing two synthetic polyolester (POE)
¦lubricants. One oil (POE-1) was characterized by the supplier as a basestock oil containing no
additives and possessing a viscosity of 64 centistokes at 40 °C and a nominal water content of 50
ppm. The other oil (POE-2) was characterized by its supplier as having a viscosity of 68 centistokes
-------
at 40 °C, a nominal moisture content of 50 ppm. and containing additives for protection against
corrosion, oxidation, hydrolysis, and wear.
Moisture determination performed on the as-received oil samples gave values of 189 ppm
water for POE-1 and 208 ppm water for POE-2. Sealed glass tubes were prepared for each of the
two oils in HFC-245ca at oil concentrations of 10,20, and 30 weight percent.
Each of the tubes was subjected to temperatures ranging from -30 to +125 °C. There were no
observed phase separations of HFC-245ca with either oil over this range of concentration and
temperature. This indicates complete miscibility of HFC-245ca in both lubricants at these conditions.
Adding excess moisture (> 200 ppm) to the POE-2 lubricant and repeating the experiment did not
affect the results.
To further characterize the properties of HFC-245ca for its potential uses, a set of experiments
was performed to determine the lubricity properties of the POE-2 lubricant in the presence of HFC-
245ca, Experiments were conducted with the pure POE-2 lubricant sample as well as with POE-2
lubricant saturated with HFC-245ca. Testing consisted of Wear and Extreme Pressure (EP, also
called Step Test) tests using a Falex Pin and Vee Block test machine. Steel vee-blocks (American
National Standards Institute, ANSI No. 1137) were run against No. 8 steel pins (ANSI No. 3135).
Saturation of HFC-245ca in the lubricant was achieved by bubbling HFC-245ca through the
lubricant for 30 minutes before starting the test and continuously during the test. As a baseline
comparision, CFC-11 in mineral oil of nominal 68 centistoke viscosity at 40 °C was tested in a
similar manner.
A Wear Test consists of running a rotating steel journal against two stationary steel V-blocks
immersed in the lubricant sample. Load is applied to the V-blocks and maintained by a ratchet
mechanism. Wear is recorded as the number of teeth of the ratchet mechanism which advances to
maintain load constant during the testing period. Thus, a larger number indicates more wear and
poorer performance. Wear (endurance) life is determined when the torque increases by 10 in^bf or
when the shear pin breaks.
' 23
-------
The Extreme Pressure Test consists of two stationary V-block specimens leaded to a
predetermined value against a rotating steel pin specimen. Results of the step tests are in "pounds"
of load applied to the test pieces at failure. In this case, the larger number indicates a better
performance. The value "2885+" indicates that the test pieces did not seize after the completion of
the maximum load of the test machine (2885 lbs).
A combined test matrix was developed using a mineral oil-sulfur mixture (ASTM D 2670-88
Blend B) and argon gas as controls. Each test was performed in triplicate and the order of the tests
randomized to remove possible bias as a result of test order. Table 4 shows the test matrix with the
test sequence numbers.
Table 4. Lubricity test matrix sequence for wear tests and extreme pressure step test
Blend B
POE-2
Wear Test
EP Step Test
Wear Test
EP Step Test
Ar
-
Ar
-
Ar
245ca
-
Ar
245ca
29
23
19
7
1
4
24
30
10
28
17
18
9
IS
3
25
26
5
22
20
21
16
12
8
6
11
2
14
13
27
* - denotes samples containing only POE-2; Ar denotes POE-2 and argon; 245ca denotes POE-2 and HFC-245ca.
The Wear Test consisted of a 5-minute break-in period with 15 minutes of wear testing. The
Extreme Pressure Test also used a 5-minute break-in period followed by sequential 1-minute tests at
250 lb load increments until failure or the maximum load (@ 2885 lbs) was reached. A glass cup
with a glass flit and side arm served as the oil containment that allowed continuous bubbling of gas
through the oil during the test. This replaced the standard metal oil cup for all tests whenever a gas
(argon or HFC-245ca) was bubbled though the oil. Argon was chosen as an inert control gas since
nitrogen might react with the hot test pieces during test. A gas flow rate of 0.1 liter per minute was
maintained in all tests. The cylinder, valve, flow meter, and lines were kept heated to 40 °C due to
24
-------
the low boiling point (26 °C) of HFC-245ca. The mass flow rate for HFC-245ca was approximately
0.9 grams per minute. Results of the lubricity tests are summarized in Table 5.
Table 5. HFC-245ca and POE-2 lubricity tests results
Blend B
Castrol SW 68
Wear Test
EPStq
p Test
Wear Test
EP Step Test
-* J Ar
-
Ar
-
Ar
245ca
.
Ar
245ca
111 140
2600
2885+
41
106
19
765
1100
1250
128 165
2600
2885
seized
'45
1
765
1100
1410
117 j 162
2885+
2885+
seized
90
10
1100
1100
2885+
* - denotes samples containing only POE-2; Ar denotes POE-2 and argon; 245ca denotes POE-2 and HFC-245ca.
The test results can be summarized as follows.
1. A slight improvement in the oil performance as a result of adding the gas. This may be a
result of lower oil temperatures.
2. POE-2 performed very poorly on both the extreme pressure and wear tests. In most of the
wear tests, the test pieces seized before reaching the test load of 700 lb. Failure was caused by
galling of the bearing surfaces.
3. Addition of argon improved the wear performance of POE-2, possibly due to a reduction in
the oil temperature. On some tests, it was observed that all of the wear occurred in the last 5 minutes
of the test when the oil had reached 90-100°C.
4. Addition of HFC-245ca greatly improved the wear performance of POE-2 when compared
to the argon data. There was a modest improvement in the extreme pressure performance.
These findings suggest that the POE-2/HFC 245ca mixture is compatible, and that addition of
the refrigerant may be necessary to improve oil performance in a compressor.
25
-------
STABILITY AND MATERIALS COMPATIBILITY
As a preliminary evaluation of the thermal and hydrolytic stability of HFC-245ca and its
compatibility with common engineering materials, another series of sealed tube samples was
prepared. These samples were subjected to sustained heating at 125 °C for a period of 14 days in
accordance with the methods described in ANSI/ASHRAE (American National Standards
Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers) Standard 97-
1989 (ASHRAE, 1989), The compatibility test matrix included several metals, plastics, and
elastomers. All materials were tested with HFC-245ca both in the presence and in the absence of the
POE-2 lubricant. All tests were run in duplicate. Table 6 gives the sample matrix for the stability
and compatibility tests. Tested elastomers and plastics may be characterized as:
Buna™-H
Copolymer of 1,3-butadiene (70 %) and acrylonitrile (30 %)
Buna™-S
Copolymer of 1,3-butadienc (70-75%) and styrene (25-30%)
E-70 or EPDM
Ethylene propylene diene polymethylene rubber
Geolast®
Nitrile polypropylene
HNBR
Hydrogenated nitrile butyl rubber, hydrogenated butadiene acrylonitrile copolymer
HYP or Hypalon®
CMorosulfonated polyethylene
Kalrez®-C
Perfluoropolymer of tetrafluoroethylene and perfluoromethyl vinyl ether
Mylar®
Polyethylene teraphthalate
Natural rubber
Isoprene polymer
Neoprene 3229
Polychloroprene
Nomex®
Polymer of m-phenylenediamine and isophthalic acid chloride
Nylon® 6,6
Polymer of adipic acid and hexamethylenediamine
S-70 or SI
Silicone rubber
Teflon®
Polymer of tetrafluoroethylene
Viton®-A
Copolymer of vinylidene fluoride and hexafl uoropropylene
Figures 6 through 10 graphically display the results of the changes in volume, weight, linear
swell, and hardness for the elastomeric materials with HFC-245ca with and without the lubricant.
Values represent averages of the duplicate samples for each material. Some swelling of elastomeric
materials is desired for gaskets and O-rings to form a good seal in equipment. However, volume
increases of greater than 20 percent or linear swell of greater than 5 percent may be considered
excessive and detrimental. Also, any shrinkage of the material is not desired. A change of hardness
of ±10 percent may indicate excessive embrittlement or softening and may be
26
-------
Table 6, Compatibility test matrix
Sample Number
Material(s)
1 a,b
HFC-245ca
2 a,b
HFC-245ca/water
3 a,b
HF C-24 5 co/copper/dwniruim/steel
4 a,b
HF C-245ea/copper/alummum/ steel/waler
5 a,b
HFC-245ca/brass/bronze
6 a,b
HFC-24 5 ca/cast iron
7 a,b
HFC-245ca/HNBR
8 a,b
HFC-245ca/Hypalon™
9 a,b
HFC-245ca/Natural Rubber
10 a,b
IlFC-245ca/Geolast™
11 a»b
HFC-245ca/Buna-S™
12 a,b
HFC-245ca/E-70
13 a,b
HFC-245ca/S-70
14 a,b
HFC-245ca/Neoprene™
15 a,b
HFC-245ca/Buna-N™
16 a,b
HFC-245ca/Kalrez-Gm
17 a,b
HFC-245ca/Viton-A™
18 a,b
HFC-245ca/Teflon™
19 a,b
HFC-24 5 ca/Nomex™
20 a,b
HFC-24 5 ca/Myiar™
21 a,b
HFC-245ca/Desiccarit H-5
22a,b
HF C -245ca/Desiccant H-6
23 a,b
HFC-245ca/Desiccant 11-7
24 a,b
HFC-245ca/Desiccant H-9
25 a,b - 48 a,b
Same as samples 1-24 but with POE-2
49 a,b
HF C-245ca/Nylon 6,6
50 a,b
HFC-245ca/Nylon 6,6 w/POE-2
27
-------
UD[P1
V"U0MA
OL-S
OlKUdoDSJ
SHAM
jaqqiry
3 ZMpx
uopdjCji
HflMH
OL-a
N-Bung
-------
Buna-N
E-70
Geolast
HNBR
Hypaloo
Kalrez C
Natural Rubber
NBRS
Neoprene
S-70
Viton-A
Teflon
Mylar
Nomex
Nylon 66
-------
0£
Percent Linear Swell
T)
a
9°
PI
%
m
m
i
I"
i
Ul
Buna-N
E-70
Geolast
HNBR
Hypalon
Kalrez C
Natural Rubber
NBRS
Neoprene
S-70
Viton-A
Teflon
Mylar
Nomex
Nylon 66
in
in
u'j LUVL'fT 'i1111 *w«w*w*rw'i|!T!liTyi I'yi'i'i'i'i'yi'i mum
'••••v.sv.sv.•.•••.
iSiaESil
L i
<*
D H
11
Q- Q.
mm ©
c c
cr «¦
3, gr
n S>
I I
-------
I£
i
tft
Percent Hardness Change
i i i
M M N* i I-*
o tA o m © in o
a
jo
H
a
Buria-n
E-70
Geolast
IINBR
Hypalon
Kalrez C
Natural
Rubber
NBRS
Neoprcne
S-70
Viton
-------
considered unacceptable. Depending on where in the equipment the engineering materials are placed,
the O-ring and gasket materials may experience contact primarily with HFC-245ea or with a
combination of HFC-245ca and lubricant. Therefore, a given elastomer or plastic may be suitable
for use in one section of the equipment but not in another.
These results indicate that fluoropolymers (namely, Viton-A, Kalrez-C, and Teflon) are
especially susceptible to absorption of the hydrofluorocarbon HFC-245ca and are therefore probably
not suitable for use in refrigeration equipment utilizing this HFC. Also, Neoprene was judged to be
unacceptable. Of the remaining materials, taking all results into account, E-70 and Hypalon were
judged best for use in situations in which HFC-245ca alone was likely to contact the material. S-70
and NBRS gave the best overall performance in contact with combined HFC-245ca and POE
lubricant.
Evidence for degradation of HFC-245ca was sought by comparison of the infrared spectra and
gas chromatograms of the vapor phase from each of the aged samples against pure HFC-245ca
Degradation of the aged lubricant containing metals was checked by infrared spectral comparison
with the pure lubricant. Neither HFC-245ca nor lubricant showed any evidence of degradation in the
presence of various metals after the 2-week heating period. Some spectral changes were observed in
the liquid phase for some of the samples containing the elastomers/plastics, but these features could
not be attributed unambiguously to degradation of the elastomers/plastics or the lubricant or both.
Desiccants were the last group of materials to be tested. Specifically, each desiccant type is
analyzed for any fluoride content which might have been deposited as a result of refrigerant
degradation during accelerated aging. Fluoride determinations were performed on the aqueous
distillate collected after passing steam over a bed of desiccant mixed with a small amount of V2Oj in
a nickel tube heated to 975 °C. Fluoride concentrations in the resulting distillate were measured with
a fluoride ion selective electrode. Four desiccant types in the aluminosilicate family were aged along
with HFC-245ca and HFC-245ca/POE-2 mixture. One desiccant type showed a small amount of
fluoride deposition (<1 percent), see Table 7.
-------
Water absorption capability of each desiccant type before and after aging in the HFC-245ca
and HFC-245ca/POE-2 mixture was determined as well. Desiccants were carefully rinsed with
acetone and heptane, and then finally allowed to dry in a desiccator. After drying, each desiccant
type was weighed and then immersed in water for a 12-hour period. At the end of the immersion
period, excess water was removed and the desiccants were reweighed. Weight difference is amount
of water absorption. All four desiccants performed similarly in both the HFC-245ca and HFC-
245ca/POE-2 mixture; approximately 4 percent of water absorption capability was lost when
compared to the unaged desiccants.
Table 7. HFC-245ca/desiccant results
Desiccant Combinations
Percent
Fluoride
HX-5-HFC-245ca/HX5-POE-2
0.83/0
HX-6I-HFC-245ca/HX6-POE-2
0/0
HX-72-HFC-245ca/HX7-POE-2
0/0
HX-9J-HFC-245ca/HX9-POE-2
0/0
1 pore size = 4 angstroms
2 pore size = 3 angstroms
33
-------
4, REFRIGERANT PERFORMANCE
CYCLE MODELING
Two major uses of chlorofluorocarbons and their alternatives are in the applications of comfort
air conditioning and refrigeration. Both processes use the phase changes of a refrigerant in a vapor-
compression cycle to extract heat through evaporation from the area to be cooled and reject heat
through condensation to a high temperature sink. Thermodynamic evaluations of refrigerants were
performed in a variety of vapor-compression configurations in order to rank the alternatives with
favorable thermodynamic properties and to tailor the configuration to best match the thermodynamic
properties of the refrigerant.
Thermodynamic evaluations were performed using several in-house computer models. These
models were based on the thermodynamic properties as predicted by the CSD equation-of-state and
the thermodynamic expressions derived from this equation-of-state (Morrison and McLinden, 1986).
The computer models provided an efficient tool to investigate a variety of refrigerants and refrigerant
blends across a range of evaporating and condensing conditions and within a variety of vapor-
compression configurations.
HFC-245ea AS A CFC-11 REPLACEMENT EN CHILLERS
The primary air-conditioning use for CFC-11 is in building chillers. HFC-245ca is one of
several alternatives with normal boiling points near that of CFC-11. Table 7 presents a list of some
CFC-11 alternatives ordered by their normal boiling points along with their critical properties.
34
-------
Table 8. Properties of HFC-245ea and other CFC-11 alternatives
Refrigerants
Name
Chemical
Formula
TC
(°C)
pC
(kPa)
Tb
<°C)
HFC-245fa
1,1,1,3,3-peiitafluoropropane
CF3CH2CF2H
157.6
3644
15.4
CFC-11
Trichlorofluoromethane
CC13F
198.1
4467
23.8
HFC-245ca
1,1,2,2,3-pentafluoropropane
CF2HCF2CFH2
178.5
3855
25.1
HCFC-123
1,1,1 -trifluoro-2,2-dichloroethane
cf3chc12
183.8
3674
27-9
HFE-245fa
1,1,1-triiluoroethyl-
difhioromethylether
CF3CH2OCF2H
170.9
3730
29
HCFC-141b
1,1 -dichloro-1 -fluoroe thane
CC12FCHj
204.2
4120
32.2
One analysis used to evaluate the alternative refrigerants is the limited property method
(Kazachki, 1991; Kazachki, 1993). An important characteristic in the limited property method is k 3
a dimensionless quantity whose value provides a basic understanding of the performance of the
refrigerant in the vapor compression cycle. A large positive value of k indicates a refrigerant which
will incur significant vapor superheating during the compression process. A negative value of k
indicates a refrigerant which incurs significant losses from the throttling process. In addition,
isentropic compression of negative k refrigerants starting from saturated vapor will result in wet
compression. The sign of k is, therefore, an indicator of the appropriate cycle which should be used
to perform comparisons. Refrigerants with zero or positive k are evaluated in a vapor compression
cycle considering throttling and compression superheating losses. Refrigerants with negative k are
evaluated in a cycle with throttling and dry compression where sufficient suction superheating is
applied in order to avoid wet compression and to achieve saturated vapor at the end of the
compression process.
35
-------
With the exception of CFC-11 and HCFC-141b, all the refrigerants in this analysis, including
HFC-245ca, have negative tc's, Therefore, thermodynamic evaluations were performed using the
cycle with throttling and dry compression.
In evaluating a refrigerant, the important parameters are the efficiency of the cycle, defined as
the coefficient of performance of the cycle (i.e., throttling and superheating or throttling and dry
compression) relative to the coefficient of performance of the Carnot cycle operating between the
same temperature limits, and die volumetric capacity. For refrigerants with negative k's, it is also
important to investigate the suction superheat required to avoid wet compression.
Thermodynamic evaluations were performed at an evaporating temperature of 4 °C and two
condensing temperatures, 40 and 50 °C, in order to investigate performance at conditions typical for
chillers. Results are presented showing all five alternatives along with CFC-11. Figure 10 shows the
degrees of suction superheat which would be required to avoid wet compression for the four
refrigerants with negative k. Since both CFC-11 and HCFC-141b have positive k's, these
refrigerants will not have the wet compression problem. Figure 10 shows that at both condensing
temperatures HFC-245ca requires slightly more superheat than HCFC-123 and HFC-245fa, but
significantly less than HFE-245fa.
Figure 11 presents the efficiency of the cycle for CFC-11 and the five alternatives. At 40 °C
condensing, HFC-245ca is about 5 percent less efficient than CFC-ll and about 3 percent less than
HCFC-123, an interim replacement which is currently being retrofit into many CFC-11 systems.
36
-------
miTc = 40oC DTc = 50 °
c
1
1
HFC-245fa HFC-245ca HCFC-123 HFE-245fa
Figure 10. Superheat required to avoid wet compression for refrigerants with negative
-------
u>
00
0.95 --
a>
u
>•
u
a>
sz
o 0.85 —
>.
u
c
a>
o
£
UJ
0.75 --
0Tc = 4O°C
STc = 50°C
HFE-
245fa
Figure 11. Cycle eflBciency with throttling and superheating/dry compression
-------
u>
v©
300
CFC-11
HCFC-141b
HFC-245fa
HFC-245ca
HCFC-123
HFE-245fa
Figure 12. Cycle volumetric capacity with throttling and superheating/dry compression
-------
Volumetric capacities are shown in Figure 12. Of all the alternatives, HFC-245ca has the closest
volumetric capacities to those of CFC-11 with values about 11 percent lower. In addition, its
capacities are 6 percent higher than those of HCFC-123. Although theoretically slightly less efficient
than CFC-11 and HCFC-123, HFC=245ca appears to be a viable alternative.
Beyond performance, other considerations are necessary when selecting alternative
refrigerants. Of the five alternatives presented here, only HFC-245ca and HFC-245fa can be
considered as long-term replacements. Both HCFC-141b and the interim replacement, HCFC-123,
are also scheduled for phascout because they contain chlorine. HFE-245fa is unacceptable because
of its instability when in contact with glass at elevated temperatures.
CENTRIFUGAL CHILLER ANALYSIS
Most of the compressors used in air-conditioning chillers are centrifugal. Important
parameters for centrifugal compressors have been evaluated for HFC-245ca and compared to CFC-
11 (Kazachki and Gage, 1993). Table 9 presents some of these parameters for a compressor with an
impeller diameter of 0.5 m and a tip width of 0.025 m for selected refrigerants (pc = evaporating
pressure, pc = condensing pressure, U2 = tip speed at impeller, Ma2 = Mach number, N = rotational
impeller speed in revolutions per minute, Vg = suction flow rate, Vjj = discharge flow rate, Qg =
compressor refrigerating capacity). In developing this table the following values .have been used for
the compressor coefficients: a compressor head coefficient of 0.6, a tip flow coefficient of 0.35 and a
compressor volume flow coefficient of 0.053.
40
-------
Table 9. Centrifugal compressor characteristics at 4 °C evaporating and 40 °C condensing
temperatures.
(From Kaxachki and Page, 1993.)
Refrigerant
Pe
Pc
U2
Ma2
N
vs _
%
Qe
kPa
kPa
m/s
-
rpm
m^/s
m^/s
kW
HFC-245&
62.7
246.2
199
1.49
7603
2.62
- 2.35
1535
CFC-11
47.9
175.3
194
1.44
7410
2.56
2.29
1167
HFC-245ca
42.1
172.8
204
1.52
7802
2.7
2.41
1087
HCFC-123
39.2
154.5
188
1.49
7182
2.48
2.22
942
This analysis shows that HFC-245ca has a low condensing pressure, and therefore equipment
would not have to be pressure rated as they might with HFC-245fa. Although the volumetric flow
rate at the compressor discharge is higher for HFC-245ca than for CFC-11, the compressor's
refrigerating capacity, Qjj, with HFC-245ca is about 6 percent less than with CFC-11.
COMPRESSOR CALORIMETRY RESULTS OF CENTRIFUGAL CHILLER SIMULATION
One technique for additional evaluation of an alternative refrigerant is a calorimeter test of
both the original refrigerant and the proposed alternative refrigerant. This calorimeter test suggests
how the alternative refrigerant will perform in a certain compressor under actual operating conditions.
Information on capacity and efficiency characteristics of the tested compressor is the output of such a
test. A calorimeter evaluation was made of HFC-245ca as a potential alternative to CFC-11 under
chiller operating conditions.
Test Equipment and Method
The test rig consisted of a calorimeter and a semi-hermetic reciprocating compressor. The
original purpose of the calorimeter was for testing compressors for low and medium temperature
applications, primarily home refrigerator compressors. During initial operation with low pressure
refrigerants, it became clear that the calorimeter as originally designed would not be usable with low
41
-------
pressure refrigerants because of the significant pressure drops in the refrigerant lines relative to their
low absolute pressures. A number of calorimeter modifications were implemented to reduce the
effects of pressure drop. The compressor was designed especially for use with HFC refrigerants and
polyolester oils with materials compatible with both. The reciprocating compressor was semi-
hermetic with an air-cooled 0.56 kW (3/4 HP) electric motor and a volumetric flow rate of 1.329
1/sec (169.2 ft3/hr) at 1759 rpm.
ASHRAE Standards 23-1978 and 23-1993 (ASHRAE, 1978; ASHRAE, 1993) were used as
bases for developing the test method. Using this testing procedure, the cooling capacity was
determined by a primary calorimeter method based on the heat required to maintain the temperature in
the evaporator, and a secondary method based on the heat balance of the water cooled condenser.
Tests were performed at evaporating conditions ranging from 1 to 12 °C and condensing
temperatures from 40 to 60 °C to determine the sensitivity of the results to operating temperatures.
Conditions of interest were chosen to match chiller operation at 4.4 °C evaporating temperature and
40,6 °C condensing temperature. Rather than having saturated vapor at the evaporator outlet,
superheat of around 8 °C was maintained in order to prevent wet compression from occurring in the
compressor. To compensate for the pressure drops in the liquid lines, which are relatively high for all
low pressure refrigerants, the refrigerant was sufficiently subcooled in the condenser to achieve at
least 3 °C subcooling at the expansion valve inlet. During evaluation of the test data, the test results
were corrected back to the chiller saturated liquid and vapor conditions.
Calorimeter Test Results
Results of calorimeter testing of HFC-245ca compared to that of CFC-11 under chiller
operating conditions are shown in Figures 13 - 18. These data are plotted as the ratios of the values
for HFC-245ca to those of CFC-11. The cooling capacity (Figure 13) of HFC-245ca is somewhat
lower than that of CFC-11, this difference being more pronounced at lower evaporating temperatures
and higher condensing temperatures. Figure 14 shows the same trend in the energy efficiency ratio
-------
(EER) as capacity, with the EER of HFC-245ca being less than that for CFC-11. The ratio of
cooling capacity of HFC-245ca relative to the cooling capacity of CFC-11, as measured in the
calorimeter (shown in Figure 13), is in good agreement with the theoretical prediction of the ratio of
the capacities of these two refrigerants (as calculated from data in Figure 12). The ratio of EER of
HFC-245ca relative to the EER of CFC-11, as measured in the calorimeter (shown in Figure 14), is
slightly lower than the corresponding theoretical prediction of the ratio of the EERs of these two
refrigerants (as calculated from data in Figure 11).
Figure 15 presents the compressor power consumption for HFC-245ca relative to CFC-11. At
all conditions tested, power consumption is within 2 percent of that for CFC-11. Figures 16 and 17
show the compressor isentropic energy and volumetric efficiencies. At 4.4 °C evaporating and 40.6 °
C condensing, the compressor energy efficiency shown in Figure 16 is about 6 percent less than that
of CFC-11. This lower energy efficiency explains why the measured EERs are lower than the
predicted values. Compressor volumetric efficiencies for HFC-245ca (Figure 17) are within 3
percent of those of CFC-11 at low condensing temperatures. At the highest condensing temperature
(60 °C), volumetric efficiencies for HFC-245ca are about 5 percent lower.
Figure 18 presents the compression ratio of HFC-245ca relative to CFC-11. At 4 °C
evaporating and 40.6 °C condensing, the compression ratio of HFC-245ca is 14 percent higher than
that of CFC-11. This higher ratio is a factor in the lower compressor isentropic energy efficiency
seen with HFC-245ca.
During the testing period, the compressor operated for approximately 150 hours. No abnormal
behavior of any part of the test rig was observed. Winding temperatures at the six locations of the
compressor motor and the oil temperature at the sump were within acceptable limits for both
refrigerants in the whole range of test conditions.
43
-------
1
-u
¦u
0.98
0.96
•a 0 94
| 0.92
w>
B
=3 0.9 +
o
U
« 0.88
"3
| 0.86
0.84
0.82 +
0.8
¦Tc = 40.6 °C
-Tc = 46.1 °C
¦Tc = 54.4 °C
+
+
-+-
4 6 8 10
Evaporating Temperature (°C)
Tc = 60.0 °c
12
14
Figure 13. Cooling capacity of HFC-245ca relative to CFC-11
-------
4^
Ui
1
0.98
0.96
0.94
0.92
W
W
> 0.9 +
• p«
2
§ 0.88
0.86 --
0.84 --
0.82
0.8
¦ Tc = 40.6 °C
¦Tc = 46.1 °C
¦ Tc = 54.4 °C
¦Tc = 60.0 °C
2 4 6 8 10 12 14
Evaporating Temperature (°C)
Figure 14. Compressor energy efficiency ratio of HFC-245ca relative to CFC-11
-------
0 2 4 6 8 10 12 14
Evaporating Temperature (°C)
Figure 15. Compressor power input for HFC-245ca relative to CFC-11
-------
1
0.98 -
u
3 0.96
¦t*.
-j
W
u
©
so
v>
4>
U
a
S
o
>
« 0.9
$
0.94
0.92 -
0.88 -
0.86
¦Tc = 40.6°C
¦Tc = 46.1°C
¦Tc = 54.4 °C
+
+
4 6 8 10
Evaporating Temperature (°C)
¦Tc = 60.0°C
12
14
Figure 16. Compressor isentropic energy efficiency of HFC-245ca relative to CFC-11
-------
1.04
¦Tc = 40.6°c
¦Tc = 46.1°C
Tc = 54.4 °C
¦Tc = 60.0 °C
4 6 8 10
Evaporating Temperature(°C)
12
14
Figure 17. Compressor volumetric efficiency of HFC-245ca relative to CFC-11
-------
1.2
1.18 -
1.16 -
&
_ 1.14
4^
v©
fl
©
•p«
M
GA
4>
a 1-12 -
E
o
U
1.1 +
1.08
1.06
-Tc = 40.6°C —0—Tc = 46.1 °C -A-Tc = 54.4°C -*-Tc = 60.0 °C
+
+
4 6 8 10
Evaporating Temperature (°C)
12
14
Figure 18. Compresion ratio of HFC-245ca relative to CFC-11
-------
HFC-245ca AS A COMPONENT IN REFRIGERANT MIXTURES
Heat Pumps
With its low atmospheric lifetime and high boiling point, HFC-245a becomes a good candidate as
a zeotrope blend component for multicomponent mixtures.
A heat pump analysis code, CYCLE 11, developed by NIST was used to evaluate ternary blends
as replacements for HCFC-22 in heat pumps. Two ternary blends containing HFC-245ca were
identified as performing better than HCFC-22, both with and without internal heat exchange. Table 10
presents the modeled results for these blends.
Refrigerators/Freezers
HFC-245ca is a blend component in several mixtures which have the potential for performance
gains in the Lorentz-Meutzner refrigerator/freezer (R/F) design (Lorentz and Meutzner, 1975, Sand, et
al.,1992). This design uses two evaporators, one in the freezer and one in the refrigerator compartment,
to take advantage of the temperature glide of zeotropes which occurs during evaporation. With an
optimized zeotrope and design, performance gains of up to 25 percent over standard CFC-12 R/Fs have
been predicted. The performance of several zeotropic mixtures containing HFC-245ca were modeled
using data from the refrigerant property database, REFPROP (NIST, 1995). Table 11 gives the
predicted preferred composition ranges for the various zeotropes along with the highest modeled
coefficients of performance (COP) for each range. In Table 11, the volumetric capacities, suction
pressures, and pressure ratios correspond to the conditions which gave the highest modeled COPs It is
evident that several mixtures have lower volumetric capacities than CFC-12; therefore, a large
compressor is required to obtain identical refrigeration capacity. Two compressors designed to use
HFC-134a were used in the R/F tests, one having similar capacity to a CFC-12 compressor and the
other having approximately 50 percent greater capacity. Data reported here are for the tests using the
smaller, 750 Btu/hr (220 W) compressor only.
50
-------
Table 10. Heat pump analysis results
Refrigerants
Mass Frac.
No Internal Heat Exchange
With Internal Heat Exchange
Xi
HFC-32
x2
HFE-125
COP
VCR
kJ/m^
G.T.
°c
PR
COP
VCR
kJ/m3
G.T.
°C
PR
HFC-32/HFE-125/HFC-245ca
0.8
0.1
4.57
5530
18.3
2.87
4.58
5530
18.4
2.86
HFE-125/HFC-134a/HFC-245ca
0.1
0.8
4.37
2128
12.3
3.78
4.47
2163
12.4
3.73
HCFC-22
1
-
4.33
3402
6.2
3.02
4.33
3790
6.2
3.02
LA
Table 11. Modeled hydrofluoropropane-based zeotrope performance
Zeotrope and Pure Refrigerant
Preferred Composition
Range
(Mass %)
COP
Volumetric
Capacity
(kJ/m3)
Suction
Pressure
(kPa)
Pressure Ratio
Constituent #1
Constituent #2
HFC-245ca
HFC-134a
33/67 - 50/50
1.53
541
74
11.5
HFC-245cb
43/57 - 55.6/44.4
1.36
217
29
17
HFC-227ea
43/57 - 55.6/44.4
1.34
209
28
17.9
HFC-152a
33/67 - 50/50
1.56
509
66
11.5
HC-270
33/67 - 50/50
1.62
841
124
8.2
HFC-134a
1.41
839
109
15.2
CFC-12
1.32
747
127
9.3
-------
As indicated in Figure 19, the R/F was thoroughly instrumented to obtain essential data. Tables
12 through 17 list the performance results using a 750 Btu/hr HFC-134a compressor. The freezer
compartment temperature was set at -15 ± 0.6 °C (5 ± 1 °F ). The fresh food compartment
temperature was maintained between 3.3 and 7.2 °C (38 and 45 °F). This was done by adjusting the
refrigerant charge.
As seen in the tables, the R/F is very sensitive to refrigerant charge and capillary tube length.
Since a HFC-134a compressor was utilized, HFC-134a outperformed CFC-12 using the 3.7 and 4.9 m
capillary tube lengths but was shown to be less efficient in the 4.3 m tube test. Utilizing HFC-134a
contributed to the lower temperature/greater cooling capacity obtained in the fresh food compartment.
Previous testing of CFC-12 using a CFC-12 compressor yielded an energy consumption of 3.24
kWh/day [3.7 m capillary tube length, 2.7 °C (36.8 °F) fresh food temperature] which is comparable to
that obtained with the HFC-134a compressor. All following comparisons are between HFC-134a as the
base line case and the zeotropic mixtures.
For 3.7 and 4.3 m tubes, HFC-134a/HFC-245ca performed better than HFC-134a when the
fresh food compartment temperature was comparable; a 4 to 6 percent reduction in energy consumption
was realized, as seen in Figure 20. The fresh food compartment temperature is higher than that using
HFC-134a, indicating that additional cooling capacity is not required in cooling down the compartment
below the needed temperature. Furthermore, as shown in Table 14, the temperature rise across the
evaporator is approximately 5 C° (9 F°) using the zeotrope, whereas a temperature rise of
approximately 0.6 C° (1 F°) was seen using HFC-134a. This indicates a temperature glide of the
mixtures across the evaporator as a result of using zeotropes with significantly different boiling points.
Other zeotropes showed temperature rises averaging 2.8 C° (5 F°), as presented in Tables 15 and
16. According to Figures 20 and 21 and Table 15, utilizing HFC-245ca/HFC-152a causes a 4 percent
energy reduction in comparison to HFC-134a without diminishing the cooling capacity. The reduction
is realized for the 4.3 m capillary tube length only. HFC-245ea/HFC-152a energy consumption is
52
-------
Figure 19.Lorentz-Meutzner refrigerator/freezer and instrumentation location
53
-------
Table 12. CFC-12 refrigerator freezer performance
Cap
(m)
Energy
(kWh/d)
Power
(watts)
Run
Time(%)
Tevfz
(°F/°C)
T fz
(0F/°O
Tevffi
(°F/°C)
Tevff
(°F/°C)
Tff
(°F/°C)
Charge
(grams)
3.7
3.24
200
61.5
-1.9/-18.8
6.9/-13.9
14.9/-9.5
27.1/-2.7
36.8/2.7
510.3
3.7
2.77
190
57.9
-1.6/-18.7
6.6/-14.1
31.5/-0.3
41.8/5.4
50.1/10.1
496.1
4.3
2.88
190
54.3
-2.2/-19.0
6.3/-14.3
31/-0.6
42/5.6
51/10.6
524.5
4.3
3.04
183
58
-2.3/-19.1
6.5/-14.2
21.2/-6.0
33.7/0.9
42.8/6.0
538.6
4.9
2.77
185
55
-4.7/-20.4
6.5/-14.2
37.7/3.2
46.3/7.9
53.9/12.2
538.6
4.9
3.19
197
61.5
-3.3/-19.6
6.5/-14.2
15.8/-9.0
30.1/-1.1
39.4/4.1
581.2
Table 13. HFC-134a refrigerator freezer performance
Cap
(m)
Energy
(kWh/d)
Power
(watts)
Run
Time(%)
Tevfz
(°F/°C)
Tfe
(°F/°C)
Tevffi
(°F/°C)
Tevff
(°F/°C)
Tff
(°F/°C)
Charge
(grams)
3.7
3
185
62.9
-2.7/-19.3
6.7/-14.1
16/-8.9
30/-1.1
39.8/4.3
311.8
4.3
3.17
185
67.4
-2.8/-19.3
6.6/-14.1
12.3/-10.9
24.6/-4.1
33.7/0.9
311.8
4.3
2.62,
185
57.2
-4.7/-20.4
6.7/-14.1
42.5/5.8
51.3/10.7
58.1/14.5
283.5
4.9
2.76
170
59.8
-3/-19.4
6.7/-14.1
29.1/-1.6
42.3/5.7
51/10.6
368.5
4.9
3.13
180
65.2
-2.2/-19.0
6.5/-14.2
13.3/-16.6
27/-2.8
36/2.2
396.9
-------
Table 14. HFC-245ca/HFC-134a refrigerator/freezer performance
Cap
(m)
Energy
(kWh/d)
Power
(watts)
Run Time
(%)
Tevfz
(°F/°C)
Tfe
(°F/°C)
Tevfei
(°F/°C)
Tevfao
(°F/°C)
Tevffi
(°F/°C)
^evffo
(°F/°C)
Tff
(°F/°C)
Charge
(grams)
Mixture
(%)
3.7
3.36
140
Non-Stop
-4.6/-20.3
5.5/-14.7
-13.1/-25.0
0.4/-17.6
16.7/-8.5
26.4/-3.1
36.7/2.6
368.5
50/50
3.7
3.21
140
Non-Stop
-0.7/-18.2
9.1/-12.7
-12.2/-24.4
5.3/-14.8
22.3/-5.4
35.2/1.8
43.2/6.2
382.7
50/50
3.7
2.98
140
83.5
¦At-20.0
6.7/-14.1
-12.2/-24.4
1.5/-16.9
29.9/-1.2
37.6/3.1
54.7/12.6
340.2
33/67
3.7
2.96
148
80.3
-3.9/-19.9
6.7/-14.1
-9.6/-23.1
0.4/-17.6
25.5/-3.6
34.5/1.4
48.4/9.1
354.4
33/67
3.7
2.99
150
79.6
-4.2/-20.1
6.6/-14.1
-9.31-22.9
-0.2/-17.7
22.H-5.2
29.6/-1.3
44.9/7.2
361.5
33/67
4.3
3.00
150
82.2
-4.3/-20.2
6.5/-14.2
-9.21-22.9
-0.4/—18.0
23.4M.8
32/0.0
45.9/7.7
361.5
33/67
4.9
3.21
140
90.8
-3.2/-19.6
6.5/-14.2
-14.0/-25.6
2.6/-16.3
27.3/-2.6
46.1/7.8
54.6/12.6
439.4
33/67
Wl Table 15. HFC-245ca /HFC-152a refrigerator/freezer performance
Cap
Energy
Power
Run Time
Tevft
Tfe
Tevfzi
^evfeo
^evffi
Tevffo
Tff
Charge
Mixture
(m)
(kWh/d)
(watts)
(%)
(°F/°C)
(°F/°C)
(°F/°C)
(°F/°C)
(°F/°C)
(°F/°C)
(0F/°O
(grams)
(%)
3.7
3.28
145
95.1
-1.8/-18.8
6.2-14.3
-9.31-22.9
2.2/-16.6
25.2/-3.8
29.2-1.6
36.1/2.3
340.2
50/50
4.3
3.38
143
99.2
-3.3/-19.6
5.4/-14.8
-12.3/-24.6
1.4/-17.0
26.7/-2.9
32.8/0.4
37/2.8
340.2
50/50
4.3
3.87
165
Non-Stop
1.8/-16.8
8.8/-12.9
-3.8/-19.9
4.5/-15.3
18.1/-7.7
19.6/-6.9
31.5/-0.3
354.4
50/50
4.9
3.32
140
Non-Stop
-0.9/-18.3
8/-13.3
-10.9/-23.8
4.2/-15.4
36.3/2.4
41.7/5.5
43.9/6.6
354.4
50/50
3.7
3.04
160
77.6
-1.4/-18.6
6.9/-13.9
-4.8/-20.4
1.6/-16.9
32.4/0.2
37.4/3.0
41.7/5.4
311.8
33/67
4.3
3.04
160
75.4
-1/-I8i3
6.9/-13.9
-4.3/-20.2
1.8/-16.8
30.2/-1.0
35.7/2.1
39.9/4.4
311.8
33/67
4.9
3.04
150
81.8
-1.9/-18.8
7/-13.9
-9/-22.8
2.6/-16.3
43.7/6.5
48.2/9.0
51.7/10.9
311.8
33/67
4.9
3.15
160
80.5
-0.8/-18.2
6.7/-14.1
-3.6/-19.8
1.4/-17.0
261-3.3
31.8/-0.1
37.1/2.8
340.2
33/67
-------
Table 16. HFC-245cayHFC-245cb & HFC-245ca/HFC-227ea refrigerator/freezer performance
Cap
(m)
Energy
(kWh/d)
Power
(watts)
Run Time
(%)
Tevfz
(°F/°C)
Tfe
(°F/°C)
Tevfzi
(°F/°C)
Tevfzo
(°F/°C)
Tevffi
(°F/°C)
Tevffo
(°F/°C)
Tff
(°F/°C)
Charge
(grams)
Mixture
(%)
3.7
3.06
129
Non-Stop
4.7/-15.2
13.1/-10.5
-4.4/-20.2
9.3/-12.6
43.5/6.4
48.7/9.3
50.9/10.5
340
43/57
3.7
3.07
130
Non-Stop
7.1/-13.8
15.2/-9.3
-1.4/-18.6
11.4/-11.4
43.2/6.2
48.3/9.1
50.1/10.1
440
36/64
L/1
ON
Table 17. HFC-245ca/HC-270 refrigerator/freezer performance
Cap
On)
Energy
(kWh/d)
Power
(watts)
Run Time
(%)
Tevfz
(°F/°C)
Tfe
(°F/°C)
levfti
(°F/°C)
Tevfeo
(°F/°C)
Tevffi
(°F/°C)
Tevffo
(°F/°C)
Tff
(°F/°C)
Charge
(grams)
Mixture
(%)
3.7
2.67
170
62.8
-2.6/-19.2
6.9/-13.9
-7.1/-21.7
1.9/-16.7
32.7/0.4
48.5/9.2
52.8/11.6
170
50/50
3.7
2.71
180
60
-3.9/-19.9
7.0/-13.9
-6.3/-7.1
-0.4/-18.0
27.9/-2.3
43.7/6.5
48.1/8.9
177
50/50
4.3
2.61
180
59.1
-2.7/-19.3
6.9/-13.9
-4.3/-20.2
0.2/-17.7
27.8/-2.3
42.8/6.0
47.3/8.5
177
50/50
-------
3.5
3.7 4.3 4.9
Capillary Tube Length (m)
Figure 20. Performance of LM/RF using 750 Btu/hr compressor (Tfe =
-14.1 °C)
-------
HFC-134a
HFC-
245ca/HFC-
134a
(33:67)
HFC-
245ca/HFC-
152a
(33:67)
HFC-
245ca/HC-
270 (50:50)
HFC-
245ca/HC-
270 (67:33)
Figure 21. Better energy reduction performance of LM/RF using 750 Btu/hr compressor
(Tfe = -14.1 °
-------
comparable to HFC-134a for the 4.9 m capillary tube length, Zeotropic mixtures shown in Table 16
(HFC-245ca/HFC-245cb and HFC-245ca/HFC-227ea) could not bring down the freezer compartment
temperature to its set point of -15 °C (5 °F). Therefore, the compressor never cycled off. Also, for the -
refrigerants in Table 16, the fresh food compartment temperature was higher than the desired 7.2 °C (45
°F). The lower capacity of both mixtures and the higher boiling temperatures of HFC -245cb and HFC-
227ea constituents than other low-boiler components contributed to the poor performance of the
zeotropes. The hydrocarbon mixture, HFC-245ca/HC-270 (50/50 percent composition), outperforms
HFC-134a and all the other zeotropic mixtures tested. Table 17 reveals 9.7 and 19.2 percent energy
reductions compared to HFC-134a using the 3.7 and 4.3 m capillary tube lengths, respectively. The
fresh food compartment capacity is not comparable; the compartment temperature ranges from 4.4 to
7.6 C° (8 to 13.6 F°) higher than that of HFC-134a. Yet, the fresh food compartment temperature is ±
1.7 C° (3 F°) of the desired temperature. Similar results are seen using the 67/33 percent mixture of
HFC-245ca/HC-270.
Figures 22 and 23 show the normalized fresh food compartment temperature and compressor run
time. Only the better performing refrigerants shown in Figure 21 are included in Figure 22. The fresh
food compartment temperature used to normalize results is 7,2 °C (45 °F); the value specified in the .
testing standard. Figure 22 shows that all the better performing fresh food temperatures are close to
that specified by the testing standard. The fresh food compartment temperature for HFC-134a is
farthest from the specified standard. Figure 23 shows that the compressor run time of the best
performer (HFC-245ca/HC-270) is comparable to that of HFC-134a, yet with a much lower energy
consumption, as shown in Figure 21. Even though the other refrigerants in Figure 23 have longer run
time than HFC-134a, they do not perform better.
59
-------
2
o\
©
«
5-
3
-------
HFC-245ca/HC-270 (67:33)
HFC-245ca/HC-270 (50:50)
HFC-245ca/HFC-152a
(33:67)
HFC-245ca/HFC-134a
(33:67)
HFC-134a
0 10 20 30 40 50 60 70 80 90 100
Compressor Run Time (%)
Figure 23. Compressor run time comparison
-------
In conclusion, the model prediction provided reasonable approximation regarding the
performance of the zeotropes listed in Table 11, Two mixtures predicted to outperform HFC-134a,
HFC-245ca/HFC-134a, and HFC-245ca/HFC-152a, performed comparable to it, and a third, HFC-
245ca/HC-270, performed better, as predicted. HFC-245ca/HC-270 outperformed all zeotropie
mixtures and HFC-134a. The mixture energy consumption reductions were approximately 16
percent in comparison to HFC-134a, Even though HFC-245ca/HC-270 outperforms HFC-134a, its
flammability should be considered before it is used. This research provides data that show that some
zeotropie mixtures utilized in a LM R/F can perform comparably to or outperform a single
component refrigerant in similar equipment. Yet, the lower volumetric capacity of mixtures in
comparison to HFC-134a suggests that their performance could be increased by employing a larger
compressor. This is also true for other zeotropie mixtures listed in Table 11.
Gas chromatography (GC) was used to analyze the running composition of a selected mixture.
A charged 33/67 weight percent mixture of HFC-245ca/HFC-134a was analyzed. Results revealed
that the running composition was 22/78 weight percent. This result suggests that a larger quantity of
HFC-134a is required in the charged mixture to obtain the composition that is predicted to perform
8.5 percent better than HFC-134a alone. Chen and Kruse (1995) stated that the circulating
concentrations at the condenser liquid outlet and compressor suction and discharge lines were the
same at steady state, but because GC analysis requires a liquid sample to be expanded to vapor, the
accuracy of the concentration measurement from the liquid sample could be less than for the vapor
sample. Chen and Kruse concentration results using liquid and vapor samples from an air-
conditioning test rig showed a 1.4 percent difference. If a similar deviation is assumed for this
sample, there still remains a significant composition shift. Chen and Kruse concluded that the
composition shift was due mainly to the differential holdup in the two-phase flow regions in the
condenser and evaporator.
62
-------
5. INSULATION FOAM PERFORMANCE
Because it has properties similar to CFC-11, HFC-245ca can be considered as a long-term
replacement for CFC-11 as a blowing agent/insulating gas in the formation of rigid polyisocyanurate
and polyurethane insulation foams. HCFC-141b (1,1 -dichloro-1 -fluorocthanc) has been recently
widely adopted as an interim blowing agent to replace CFC-11 in foams, but this alternative is
scheduled for production phaseout in the year 2002 due to its ozone depletion potential. With a
normal boiling point close to that of CFC-11, zero ozone depletion potential, a low atmospheric
lifetime, moderate flammability, and an acceptable vapor thermal conductivity, HFC-245ca appears
to be a candidate as a drop-in replacement for CFC-11 in this application.
EPA STUDY
A technical paper by Sharpe et al. (Sharpe, 1994) reports on a limited experimental study
sponsored by EPA to evaluate the performance of HFC-245ca as a foam blowing agent. In this
study, a basic urethane foam was formulated in a hand-pourable formulation with both CFC-11 and
HFC-245ca blowing agents to provide a simple comparison of blowing agent performance. HFC-
245ca blended quite readily with the foam chemicals and could be easily redispersed with stirring
even after 3 months of settling. Reactivity effects were determined by performing a number of cup
reactivity tests (e.g., cream time, gel time, rise time, density) with both CFC-11 and HFC-245ca.
These results showed that HFC-245ca has very similar reactivity characteristics to CFC-11
Automated reactivity measurements also made with the two blowing agents showed slightly different
reaction times and reaction height, but these could be changed by using a more optimized catalyst
system.
Free rise samples of each foam were tested for various physical and mechanical properties
(compressive strength, tensile strength, friability). Resulting values indicated that foams with
approximately equivalent properties could be prepared using the two blowing agents. Micrographs of
63
-------
the foam samples were prepared as a preliminary comparison of foam cell structure and showed that
the HFC-245 ca had a cell size and cell size distribution similar to CFC-11.
Test panels were also made with each of the foam systems using a closed mold for evaluation
of foam adhesion properties and thermal and aging characteristics. Bond adhesion of the two
materials was comparable at low(-196 °C), normal (22 °C), and elevated (93 °C) temperatures.
Thermal conductivity measurements of molded foam samples indicate that the HFC-245ca sample
had an initial thermal conductivity approximately 24 percent higher than the CFC-11 sample (0.021
versus 0.017 W/m K). In these samples, the HFC-245ca sample appeared to be aging at a similar
rate as the CFC-11 sample. Samples were also subjected to longer-term aging tests by two different
methods. Overall, the HFC-245ca foam aging trend appeared to parallel that of the CFC-11 foam,
but with rates averaging 20 percent higher.
The overall conclusions of the EPA tests in this simple, non-optimized urethane formulation
were that HFC-245ca should be easy to process using conventional foaming equipment but that
changes in formulations may be required to approach equivalent insulation characteristics (or other
properties) compared to CFC-11 foam.
INDUSTRY STUDY
Allied-Signal, Inc. (Rnopeck et al.5 1993a) conducted an evaluation of three HFC-245 isomers,
including HFC-245ca, as next generation foam blowing agents. Experimental property
measurements and foam evaluation showed that satisfactory foams can be made using HFC-245ca,
HFC-245cb, and HFC-245fa as the sole blowing agent. The thermal conductivity of foams evaluated
appears to be in the following order; CFC-11< HFC-245 isomers < HCFC-141b. Allied-Signal noted
that a significant amount of additional work would be required to folly characterize the toxicological
properties of these chemicals before they can be used in producing insulation.
Allied-Signal presented an update of their work on HFC-245 isomers in another 1993 paper
(Knopeck et al., 1993b). The emphasis in the new work was on HFC-245fa because more recent
-------
applications work had been done on this isomer. However, they emphasized that none of the HFC-
245 isomers had been eliminated from consideration and were all the subject of ongoing
developmental work.
65
-------
6. REFERENCES
ASHRAE 97-1989, "Sealed Glass Tube Method to Test the Chemical Stability of Material for
Use Within Refrigerant Systems," American Society of Heating, Refrigerating and Air-Conditioning
Engineers, 1791 Tullie Circle, NE, Atlanta, GA, 1989.
ASHRAE Standard 23-1978, "Methods of Testing for Rating Positive Displacement
Refrigerant Compressors," American Society of Heating, Refrigerating and Air-Conditioning
Engineers, 1791 Tullie Circle, NE, Atlanta, GA, 1978.
ASHRAE Standard 23-1993, "Methods of Testing for Rating Positive Displacement
Refrigerant Compressors," American Society of Heating, Refrigerating and Air-Conditioning
Engineers, 1791 Tullie Circle, NE, Atlanta, GA, 1993.
ASTM (American Society for Testing and Materials) Standard Test Method for Concentration
Limits of Flammability of Chemicals, ASTM Designation: E681-94, 1916 Race St., Philadelphia,
PA, 1994.
ASTM (American Society for Testing and Materials) Standard Test Method for Measuring
Wear Properties of Fluid Lubricants (Falex Pin and Vee Block Method), ASTM Designation:
D2670-88, 1916 Race St., Philadelphia, PA, 1985.
Beyerlein, A. L., et al., New Fluorinated Propane and Butane Derivatives and HFC-
245ca/HFC-338mccq Mixtures as Alternative CFCs and HCFCs, Proceedings of 1994 International
CFC and Halon Alternatives Conference, Washington, DC, October 24-26, 1994.
Chen, J. and H. Kruse, Calculating Circulation Concentration of Zeotropic Refrigerant
66
-------
Mixtures, HVAC&R Research Journal. Vol. 1, No. 3,219-230,1995.
Doerr, R, and S. Kujak, Compatibility of Refrigerants and Lubricants with Motor Materials,
Final Report, Vol. 1, The Air-Conditioning and Refrigeration Technology Institute, DOE/CE/23810-
13, May 1993.
Doerr, R. and T. Waite, Compatibility of Refrigerants and Lubricants with Motor Materials
Under Retrofit Conditions, Quarterly Technical Progress Report for 1 October 1994 to 31 December
1994, The Air-Conditioning and Refrigeration Technology Institute, DOE/CE/23810-5 IB, January
1995.
Domalski, E. S. and E. D. Hearing, Estimation of the Thermodynamic Properties of C-H-N-O-
S-Halogen Compounds at 298.15K. J. Phys. Chem. Ref. Data 22, No. 4,1993.
EPA (U. S. Environmental Protection Agency) Health Effects Test Guidelines, Office of Toxic
Substances, Federal Register, SO, No. 188, Part 798.1150, September 1985.
Gage, C. L., Environmental Research Brief: Equation-of-State Parameters for Potential CFC
and HCFC Replacements. EPA-600/S-93-003, Research Triangle Park, NC, February 1993.
KazachM, G. S., Derivation of Dimensionless Parameter for Thermodynamic Evaluation of
Refrigerants in Vapour-Compression Cycles. In: Proceedings of the 18th International Congress of
Refrigeration, Montreal, Canada, pp. 597-601,199.1.
Kazachki, G. S., Criteria for the Evaluation of the Efficiency Improvements in Vapor
Compression Cycles Using Internal Heat Exchange. In: Proceedings of the 16th World Energy
Engineering and 2nd Environmental Technology Congress, Atlanta, GA, 1993.
67
-------
Kazachki, G. S. and C. L. Gage, Hemodynamic Evaluation and Compressor Characteristics
of HFC-236ea and HFC-245ca as CFC-114 and CFC-ll Replacements in Chillers. In: Proceedings
of the 1993 International CFC and Halon Alternatives Conference, Washington, DC, 1993, pp. 167-
176.
Knopeck, G. M., R. C. Parker, R. G. Richard, and I. R. Shankland, Status Report on the
Development of a Liquid HFC Blowing Agent, Society of the Plastics Industries Polvurethanes 1993
Conference, Boston, MA, October 9, 1993a.
Knopeck, G. M., R. C. Parker, R, G, Richard, and I, R. Shankland, Evaluation of Next
Generation Blowing Agents, Society of the Plastics Industries Polyurethanes 1993 Conference,
Boston, MA, October 10, 1993b.
Lorentz, A. and D. Meutzner, An application of non-azeotropic two-component refrigerants in
domestic refrigerators and home freezers. 13th International Congress of Refrigeration, Moscow,
1975.
Morrison, G. and M. 0. McLindcn, Application of a Hard Sphere Equation of State to
Refrigerants and Refrigerant Mixtures, NBS Technical Note 1226, August 1986.
NASA (National Aeronautics and Space Administration), Chemical Kinetics and
Photochemical Data for Use in Stratospheric Modeling, Evaluation No. 10, Jet Propulsion
Laboratory Publication 92-20, August 1992.
Nelson, Thomas P., Findings of the Chlorofluorocarbon Chemical Substitutes International
Committee, EPA-600/9-88-009 (NTIS PB88-195664), Research Triangle Park, NC, April 1988.
68
-------
NIST Standard Reference Database 23, "Thermodynamic Properties of Refrigerants and
Refrigerant Mixtures" (REFPROP) Version 5.0, National Institute of Standards and Technology,
1995, Boulder, CO.
Prin, R. G., et al., Atmospheric Trends and Lifetime of CH3CCI3 and Global OH
Concentrations, Science, Vol. 269, 187-192, July 14, 1995.
Sand, J. R., E. A. Vineyard, and V. D. Baxter, Laboratory Evaluation of Ozone-Safe
Nonazeotropic Refrigerant Mixture in a Lorenz-Meutzner Refrigerator Freezer Design. ASHRAE
Transactions: Symposia, 1992.
Sharpc, J., D. Mac Arthur, T. Kollie, R. Graves, M. Liu, and R Hendriks, Evaluation of HFC-
245ca and HFC-236ea as Foam Blowing Agents, Society of the Plastics Industries Polyurethanes
1994 Conference, Boston, MA, October 9, 1994.
United Nations Environment Programme, Montreal Protocol on Substances that Deplete the
Ozone Layer - Final Act, 1987.
69
-------
TECHNICAL REPORT DATA T ,
(Please read instructions on the reverse before completini I III 1 ||| III 11 III III |
1. REPORT NO. 2.
EPA-600/R-96-132
3.re i miiimilliiiiiimi hi |
.PB9.7_-_125.413 J
4. TITLE AND SUBTITLE
New Chemical Alternative for Ozone-depleting
Substances: HFC-245ca
5. REPORT DATE
December. • 1996
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
N.D.Smith, C.L.Gage, E. Baskin. and R. V. Hendriks
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
See Block 12
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
NA (inhouse)
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Air Pollution Prevention and Control Division
Research Triangle Park, NO 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final; 8/87 - 6/96
14. SPONSORING AGENCY CODE
EPA/600/13
is.supplementary notes appcd project officer is N. Dean Smith, Mail Drop 63, 919/541-
2708.0
,6' ABSTRiv2Jhe report gives results of a preliminary evaluation of a new hydrofluoro-
carbon (HFC)—HFC-245ca or 1,1,2, 2,3-pentafluoropropane—as a possible alterna-
tive for chlorofluorocarbon (CFC)-ll (trichlorofluoromethane) and hydrochloro-
fluorocarbon (HCFC)-123 (1,1, l-trifluoro-2, 2-dichloroethane) refrigerant for low-
pressure chillers and as a possible alternative for CFC-U1 and HCFC-141b (1-fluoro-
1,1-dichloroethane) blowing agents for polyisocyanurate/ polyurethane insulation
foams,-(NQ^E^HECA.form^ a class of chemicals having the potential to replace strat-
ospheric ozone depleting subsi'MCtes'suchi as CFCs and HCFCs.)-Evaluation tests in-
cluded an examination of its flammability, stability, thermophysical properties, lu-
bricant miscibility and lubricity, materials compatibility, acute inhalation toxicity,
and refrigeration performance. An azeotrope composed of HFC-245ca and HFC-
338mccq (1,1,1, 2, 3, 4, 4,4-octafluorobutane) was also-examined from the standpoint
of reducing the flammability of HFC"-245ca.--=^=ri=^^i'
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. eoSATt Field/Group
Pollution Stratosphere
Refrigerants Ozone
Halohydrocarbons
Blowing Agents
Insulation
Azeotropes
Pollution Prevention
Stationary Sources
Hydrofluorocarbons
Global Warming
13 B 04 A
13A 07B
07C
UG
14 G
07D
18, DISTRIBUTION STATEMENT
Release to Public
18. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
793
20. SECURITY CLASS (This pagef
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
------- |