Refrigerant Data Update

Transcription

1 Refrigerant Data Update This article summarizes key physical, safety, and environmental data for refrigerants. It covers refrigerants that were widely used historically, that are in common use today, and selected candidates being considered for future use. The history of refrigerants, since the introduction of mechanical vapor-compression refrigeration in the 183s, comprises four periods characterized by the dominant selection criteria beyond basic suitability. Figure 1 summarizes four distinct generations and identifies key refrigerant groups or criteria for them. Most refrigerants in the first generation, a period of approximately 1 years, were solvents, fuels, or other volatile fluids familiar to early practitioners from other uses, essentially whatever worked. Broad commercialization of domestic refrigerators By JAMES M. CALM, PE, Engineering Consultant, Great Falls, Va., and GLENN C. HOURAHAN, PE, Air Conditioning Contractors of America, Arlington, Va. spurred a shift to a second generation. It differed with attention to improved safety and durability, leading to the advent of fluorochemical refrigerants. International response to protect the stratospheric ozone layer forced scheduled phaseouts of ozone-depleting refrigerants, among them chlorofluorocarbons (CFCs), such as R-12, and in the future also hydrochlorofluorocarbons (HCFCs), such as R-22. The measures also addressed similar chemicals for other applications, such as many widely used aerosol propellants, foam blowing agents, fire suppression agents (notably halons), and solvents. The third-generation shift to hydrofluorocarbon (HFC) and other refrigerants for ozone protection was perceived as a long-term solution, but growing awareness of climate change as FIGURE 1. Refrigerant progression. Copyright 26 James M. Calm James M. Calm is an internationally recognized engineering consultant specializing in heating, air-conditioning, and refrigeration systems. He is an ASHRAE Fellow; serves as lead author on refrigerants for the UNEommittee assessing technical options for refrigeration, air conditioning, and heat pumps; and has been directly involved in standards, codes, regulatory, and treaty actions impacting refrigerant use. As vice president of research and technology for the Air Conditioning Contractors of America (ACCA), Glenn C. Hourahan directs its technical, standards, and codes activities. He is actively involved in technical committees of a number of industry organizations. Between them, they have more than 6 years experience in design, construction, operation, and research of air-conditioning and refrigeration systems and authored more than 2 papers and articles. 5 January 27 HPAC Engineering J. M. Calm and G. C. Hourahan, Refrigerant Data Update, Heating/ Piping/Air Conditioning Engineering, 79(1):5-64, January 27

2 a more significant or at least much more challenging environmental issue now heralds a looming fourth generation to address global warming. This term is a bit misleading, as the impacts of climate change include warming in most regions but cooling in some (for example, in parts of Europe). It also includes sea level rise and attendant coastal land loss, changes in growing seasons and soil moisture retention (and, therefore, crop yields), and spread of diseases such as malaria now nearly localized to equatorial regions. In short, global climate change may impact virtually all aspects of life and raises significant international and intergenerational equity issues. Interestingly, some of the fluids considered natural refrigerants (primarily ammonia, carbon dioxide, hydrocarbons, and water) in the first generation are being re-examined to replace synthetic refrigerants (primarily fluorochemicals) because of environmental concerns. Many of the claims and counterclaims for such fluids are more emotional or marketing-based than technical. Most of the safety, durability, and performance issues that drove early refrigerant shifts remain concerns today, complicated by focus on low ozone depletion potential (ODP), low global warming potential (), short atmospheric lifetime (τ atm ), and, perhaps most importantly, high efficiency. There are linkages that force trade-offs among these criteria, but of them can be ignored. 1 Manufacturers have commercialized more than 3 new refrigerants in the past decade, and they are examining additional candidates. Most new refrigerants are blends, because the options for suitable single-compound refrigerants are much more limited and generally already exploited. Users should expect a number of additional introductions as the phaseout approaches for R-22, now the most widely used refrigerant. A similar flurry of service fluid introductions occurred with the earlier phaseout of R-12 (then, the most widely used refrigerant) and R- 52. Data refinement continues for both existing and new refrigerants with improvements in measurement methods, further studies, and new understanding, especially of environmental impacts. REFRIGERANT DATA TABLES This article provides two tables that update 2,3,4 and expand selected physical, safety, and environmental data for common refrigerants (retired and current) and leading candidates. The two tables contain the same data sorted differently. Table 1 is arranged by standard refrigerant designations, while Table 2 is sorted by refrigerant boiling points. Table 1 lends itself to finding information on a specific refrigerant. The sort order for Table 2 rearranges the refrigerants in coarse proximity of candidacy for similar applications, to facilitate comparisons. The parameter descriptions that follow are in the same sequence as presented in Tables 1 and 2, going from the left to the right columns. Identifiers The number shown is the standard designation based on those assigned by or recommended for addition to ANSI/ASHRAE Standard 34-24, Designation and Safety Classification of Refrigerants, 5 and addenda thereto for anticipated consistency with when published. These familiar designations are used almost universally, usually preceded by R-, R, the word Refrigerant, composition-designating prefixes (for example CFC, HCFC, HFC, or HC), or manufacturer trade names. The chemical formula indicates the molecular makeup of the single-compound refrigerants, namely those consisting of only one chemical substance. The blend composition is shown for refrigerant blends, namely those consisting of two or more chemicals that are mixed to obtain desired characteristics. The composition consists of two parts. The first identifies the components, in order of increasing normal boiling points and separated by slashes. The second part, enclosed in parentheses, indicates the fractions (as percentages) of those components in the same order. The tables also indicate common names by which some refrigerants are frequently identified. Physical properties The molecular is a calculated value based on the atomic weights recognized by International Union of Pure and Applied Chemists (IUPAC). 6 It indicates the in grams of a mole of the refrigerant or, for blends, the -weighted average of a mole of the mixture. The normal boiling point () is the temperature at which liquid refrigerant boils at standard atmospheric pressure, namely kpa ( psia). The and most dimensional units in the tables are shown in both metric (SI) and inch-pound (IP) units of measure. The temperature of the sublimation point is shown for refrigerants that sublimate, such as R-744 (carbon dioxide). The bubble point temperature at which a bubble first appears and boiling begins is shown as the for blends. Unlike single-compound refrigerants that boil at a single temperature for a given pressure, the dissimilar volatilities of components cause mixture boiling to span a range between the bubble point and dew point temperatures. The dew point is so named because it is the condition at which condensation begins when the blend is cooled. The critical temperature ( ) is the temperature at the critical point of the refrigerant, namely where the properties of the liquid and vapor phases are identical. Unless actually determined, the values shown for blends are the weighted averages of the component s, sometimes referred to as the pseudo-critical temperature. The critical pressure ( ) is the pressure at the critical point. The and critical properties suggest the application range for which an individual refrigerant might be suitable. Those with extremely low s lend themselves to ultralow temperature refrigeration including cryogenic applications. Those with high s generally are limited to high-temperature applica- HPAC Engineering January 27 51

3 tions, such as chillers and industrial heat pumps. Both capacity and efficiency decline when condensing temperatures approach the in a typical vapor-compression (reverse-rankine) cycle, the one most commonly used. will exceed the operating pressure except in transcritical cycles, which are uncommon except for R-744 (carbon dioxide). It is useful to compare relative operating pressures because practical cycles usually are designed to condense at 7 to 9 percent of the (on an absolute basis) and, therefore, at corresponding fractions of the. 1,7 Safety data The first safety column included in the tables tabulates the occupational exposure limit (). It is an indication of chronic (long-term, repeat exposure) toxicity of the refrigerant for trained individuals likely to be exposed during their work. Common s include the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value-Time Weighted Average (TLV-TWA), the American Industrial Hygiene Association (AIHA) Workplace Environmental Exposure Level (WEEL) guide, the Deutsche Forschungsgemeinschaft (DFG) maximale Arbeitsplatz Konzentration (MAK, the maximum workplace concentration), the Japan Society of Occupational Health (JSOH), and the U.S. Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL). Some countries and manufacturers refer to them as the acceptable exposure limit (AEL), industrial exposure limit (IEL), workplace exposure standard, or with similar terms. These measures indicate recommended or adopted limits for workplace exposures for trained personnel for typical workdays and work weeks. s normally are expressed in ppm by volume (ppm v/v) on a time-weighted average (TWA) basis for a normal workday and workweek, unless preceded by a C to designate a ceiling limit. The lower flammability limit () is the lowest concentration at which the refrigerant burns in air under prescribed test conditions. It is an indication of flammability. The heat of combustion () is an indicator of how much energy the refrigerant releases when it burns in air, assuming complete reaction to the most stable products in their vapor state. Negative values indicate endothermic reactions (those that require heat to proceed), while positive values indicate exothermic reactions (those that liberate heat). The ASHRAE Standard 34 safety group is an assigned classification that is based on data used to determine the TLV-TWA (or consistent measure),, and. It comprises a letter (A or B) that indicates relative toxicity followed by a number (1, 2, or 3) that indicates relative flammability. These classifications are widely used in mechanical and fire construction codes to determine requirements to promote safe use. Most of these code provisions are based on ASHRAE Standard 15, Safety Standard for Refrigeration Systems. Some of the classifications shown are followed by the lower case letter r. It signifies that the committee responsible for has recommended revision or addition of the classification shown, but final approval and/or publication is still pending. Similarly, a d indicates a deletion. Blends were assigned dual classifications, such as /, in the past to indicate the s both as formulated and for the worst case of fractionation. That practice changed to assignment of a single reflecting the worst case of fractionation for specified leak and refill scenarios. Environmental data The atmospheric lifetime (τ atm ) is an indication of the average persistence of refrigerant released into the atmosphere until it decomposes, reacts with other chemicals, or is otherwise removed. While τ atm factors into additional environmental parameters, it also is significant in its own right. It suggests the potential for atmospheric accumulation of released refrigerants (and other chemicals). Long atmospheric lifetime implies the potential for slow recovery from environmental problems, both those already known and additional concerns identified in the future. The values shown for the refrigerant lives are composite atmospheric lifetimes. The lifetimes also can be shown separately for the tropospheric (lower atmosphere, where we live), stratospheric (next layer, where global depletion of ozone is a concern), and higher layers because the dominant atmospheric chemistry changes between layers. The ozone depletion potential (ODP) is a normalized indicator, based on a value of one for R-11, of the ability of refrigerants (and other chemicals) to destroy stratospheric ozone molecules. The values shown in Tables 1 and 2 are semi-empirical ODPs, calculated values that incorporate adjustments for observed atmospheric measurements. 8 The ODPs shown for blends are weighted averages. The semi-empirical approach is conceptually more accurate than other measures, though it is still evolving with further and improved measurements and understanding. Previous summaries 2,3,4 focused on modeled ODP values, then deemed the most indicative of environmental impacts based on consensus international assessments. There are several other ODP indices, including time-dependent and regulatory variations. Time-dependent ODPs use chemicals other than R-11 as the reference. Normalizing values to short-lived compounds emphasizes near-term impacts, but discounts long-term effects. Timedependent ODPs are not cited often, because release of ozone-depleting substances already has peaked, and recovery of the stratospheric ozone layer is under way. The global warming potential () is a normalized indicator of the potency to warm the planet by action as a greenhouse gas. The values shown are relative to carbon dioxide (CO 2 ) for an integration period of 1 years, again based on Text continued on Page January 27 HPAC Engineering

4 TABLE 1. Physical, safety, and environmental data for refrigerants (sorted by ASHRAE Standard 34 designations). Refrigerant Physical data Safety data Environmental data I a E b 142b 143a 152a E ea 236fa 245ca 245fa E245cb1 C27 29 C318 E347mmy1 CCl 3 F CBrClF 2, halon 1211 CCl 2 F 2 CBrF 3, halon 131 CClF 3 CF 3 I, trifluoroiodomethane CF 4, carbon tetrafluoride CHCl 2 F CHClF 2 CHF 3, fluoroform CH 2 Cl 2, methylene chloride CH 2 ClF CH 2 F 2, methylene fluoride CH 3 F, methyl fluoride CH 4, methane CCl 2 FCClF 2 CClF 2 CClF 2 CClF 2 CF 3 CF 3 CF 3, perfluoroethane CHCl 2 CF 3 CHClFCF 3 CHF 2 CF 3 CH 2 FCF 3 CHF 2 -O-CHF 2 CH 3 CCl 2 F CH 3 CClF 2 CH 3 CF 3 CH 3 CHF 2 CH 3 CH 2 Cl, ethyl chloride CH 3 CH 2 F, ethyl fluoride CH 3 CH 3, ethane CH 3 -O-CH 3, DME CF 3 CF 2 CF 3, perfluoropropane CF 3 CHFCF 3 CF 3 CH 2 CF 3 CH 2 FCF 2 CHF 2 CHF 2 CH 2 CF 3 CH 3 -O-CF 2 -CF 3 -CH 2 -CH 2 -CH 2 -, cyclopropane CH 3 CH 2 CH 3, propane -CF 2 -CF 2 -CF 2 -CF 2 - CF 3 -CF(OCH 3 )-CF C flam B ~ yr ~ ~ ~ HPAC Engineering January 27 53

5 TABLE 1 (continued). Physical, safety, and environmental data for refrigerants (sorted by ASHRAE Standard 34 designations). Refrigerant Physical data Safety data Environmental data 4 >> 4 >> 41A 41B 41C 42A 42B 43A 43B 44A 45A 46A 47A 47B 47C 47D 47E 48A 49A 49B 41A 41B R-12/114 (5./5.), R-4 (5/5) R-12/114 (6./4.), R-4 (6/4) R-22/152a/124 (53./13./34.), MP39 R-22/152a/124 (61./11./28.), MP66 R-22/152a/124 (33./15./52.), MP52 R-125/29/22 (6./2./38.), HP8 R-125/29/22 (38./2./6.), HP81 R-29/22/218 (5./75./2.), 69-S R-29/22/218 (5./56./39.), 69-L R-125/143a/134a (44./52./4.), HP62 and FX-7 R-22/152a/142b/C318 (45./7./5.5/42.5), G215 R-22/6a/142b (55./4./41.), Autofrost-X3 R-32/125/134a (2./4./4.), Klea 6 R-32/125/134a (1./7./2.), Klea 61 R-32/125/134a (23./25./52.), Klea 66 and Suva 9 R-32/125/134a (15./15./7.) R-32/125/134a (25./15./6.) R-125/143a/22 (7./46./47.), FX-1 R-22/124/142b (6./25./15.), FX-56 R-22/124/142b (65./25./1.), FX-57 R-32/125 (5./5.), Suva 91 and AZ-2 R-32/125 (45./55.) d yr January 27 HPAC Engineering

6 TABLE 1 (continued). Physical, safety, and environmental data for refrigerants (sorted by ASHRAE Standard 34 designations). Refrigerant Physical data Safety data Environmental data 411A 411B 412A 413A 414A 414B 415A 415B 416A 417A 418A 419A 42A 421A 421B 422A 422B 422C 422D 423A 424A 425A R-127/22/152a (1.5/87.5/11.), G218A R-127/22/152a (3./94./3.), G218B R-127/22/152a (3./95.5/1.5), G218C R-22/218/142b (7./5./25.), Arcton TP5R R-218/134a/6a (9./88./3.), Isceon MO49 R-22/124/6a/142b (51./28.5/4./16.5), GHG-X4 R-22/124/6a/142b (5./39./1.5/9.5), Hot Shot R-22/152a (82./18.) R-22/152a (25./75.), THR1b R-134a/124/6 (59./39.5/1.5), FR-12 R-125/134a/6 (46.6/5./3.4), Isceon MO59 and NU-22 R-29/22/152a (1.5/96./2.5), THR3b R-125/134a/E17 (77./19./4.), FX-9 R-134a/142b (88./12.) R-134a/142b (8.6/19.4), RB-276 R-125/134a (58./42.) R-125/134a (85./15.) R-125/134a/6a (85.1/11.5/3.4), One Shot and Isceon MO79 R-125/134a/6a (55./42./3.) R-125/134a/6a (82./15./3.) R-125/134a/6a (65.1/31.5/3.4), Isceon MO29 R-134a/227ea (52.5/47.5), Isceon 39TC R-125/134a/6a/6/61a (5.5/47./.9/1./.6), RS-44 R-32/134a/227ea (18.5/69.5/12.), THR3a wff yr HPAC Engineering January 27 55

7 TABLE 1 TABLE (continued). 1 (continued). Physical, safety, safety, and and environmental data for refrigerants (sorted by ASHRAE by ASHRAE Standard Standard 34 designations). 34 designations). Refrigerant Physical data Safety data Environmental data 426A 427A 428A A 58A 58B 59A R-125/134a/6/61a (5.1/93./1.3/.6) R-32/125/143a/134a (15./25./1./5.), FX-1 R-32/125/143a/134a, (2./41./5./7.), FX-48B R-32/125/143a/134a (1./33./36./21.), HX4 R-125/143a/29/6a (77.5/2./.6/1.9), RS-52 R-12/152a (73.8/26.2) R-22/12 (75./25.) R-22/115 (48.8/51.2) R-23/13 (4.1/59.9) R-32/115 (48.2/51.8) R-12/31 (78./22.) R-31/114 (55.1/44.9) R-125/143a (5./5.), AZ-5 R-23/116 (39./61.), Klea 5R3 R-23/116 (46./54.), Suva 95 R-22/218 (44./56.), Arcton TP5R2 R-23/32/134a (4.5/21.5/74.), FX-22 R-32/125/134a/6 (1./42./45./3.) R-32/125/143a (1./45./45.), FX-4 R-32/125/161 (15./34./51.), ZJU ZH1 R-32/134a (3./7.) R-32/6 (95./5.) R-32/6a (9./1.) R-125/134a/152a (35./4./25.), GHG-X8 R-125/134a/6/61a (5./47./2.7/.3) R-125/152a/227ea (4./5./55.), GHG-X7 R-125/29/134a/E17/227ea (55.4/.6/34./2.5/7.5) wff flam flam wff r r r yr January 27 HPAC Engineering

8 TABLE 1 (continued). Physical, safety, and environmental data for refrigerants (sorted by ASHRAE Standard 34 designations). Refrigerant Physical data Safety data Environmental data 6 6a 61 61a R-125/29/218 (86./5./9.), Isceon 89 R-152a/6a (7./3.), C1 R-161/13I1 (8./2.) R-161/218/13I1 (65.4/18.2/16.4) R-17/29 (6./94.), ER22/52 R-218/134a/6 (32.7/62.8/4.5), CM1 R-29/6a (5./5.), propane/isobutane R-6a/6 (5./5.), isobutane/butane R-61/62 (9.1/9.9), pentane/hexane R-61a/61 (37./63.), isopentane/pentane R-717/E17 (6./4.), R723 CH 3 -CH 2 -CH 2 -CH 3, butane CH(CH 3 ) 2 -CH 3, isobutane CH 3 -CH 2 -CH 2 -CH 2 -CH 3, pentane (CH 3 ) 2 CH-CH 2 -CH 3, isopentane CH 3 -CH 2 -O-CH 2 -CH 3, ethyl ether HCOOCH 3, methyl formate CH 3 (NH 2 ), methylamine CH 3 -CH 2 (NH 2 ), ethylamine H 2, normal hydrogen He, helium NH 3, ammonia H 2 O, water Air (78% N 2, 21% O 2, 1% Ar, +) Ar, argon CO 2, carbon dioxide SO 2, sulfur dioxide Kr, krypton CHCl=CHCl, dielene CH 2 =CH 2, ethylene CH 3 CH=CH 2, propylene = normal boiling point; = critical temperature; = critical pressure; = occupational exposure limit in PPM by volume TWA, unless preceded by "C" for Ceiling, such as the ACGIH Threshold Limit Value (TLV-TWA), AIHA Workplace Environmental Exposure Level (WEEL), OSHA Permissible Exposure Limit (PEL), or a consistent limit (see text); = lower flammability limit (% by volume in air), flam indicates flammable but the is unknown and wff signifies that the worst case of fractionation may become flammable; = heat of combustion; ODP = ozone depletion potential (semi-empirical); = global warming potential (for 1-yr integration). Suffixes to safety classifications indicate recommended changes that are not final yet ( d for deletion and r for revision or addition) or classifications assigned as provisional ( p ); d alone indicates that a prior classification was deleted (withdrawn). Data sources are identified in the Refrigerant Database; verify the data and associated limitations in those sources before use. Copyright 26 James M. Calm, Engineering Consultant high high ^ B2 B2 > yr ~2 38 ~2 ~2 ~2 ~2 <1 ~2 ~2 ~2 ~2 <1 <1 1 3 ~2 HPAC Engineering January 27 57

9 TABLE TABLE 2. Physical, 2. safety, safety, and and environmental data for refrigerants (sorted by normal by normal boiling boiling point). point). Refrigerant Physical data Safety data Environmental data A 58B A 41B 59A 43B 42A 428A He, helium H 2, normal hydrogen Air (78% N 2, 21% O 2, 1% Ar, +) Ar, argon CH 4, methane Kr, krypton CF 4, carbon tetrafluoride CH 2 =CH 2, ethylene CH 3 CH 3, ethane R-23/13 (4.1/59.9) R-23/116 (39./61.), Klea 5R3 R-23/116 (46./54.), Suva 95 CHF 3, fluoroform CClF 3 CO 2, carbon dioxide CH 3 F, methyl fluoride CF 3 CF 3, perfluoroethane CBrF 3, halon 131 R-32/115 (48.2/51.8) R-125/29/218 (86./5./9.), Isceon 89 R-32/6a (9./1.) CH 2 F 2, methylene fluoride R-17/29 (6./94.), ER22/52 R-32/6 (95./5.) R-32/125 (5./5.), Suva 91 and AZ-2 R-32/125 (45./55.) R-22/218 (44./56.), Arcton TP5R2 R-29/22/218 (5./56./39.), 69-L R-32/125/143a (1./45./45.), FX-4 R-125/29/22 (6./2./38.), HP8 R-125/143a/29/6a (77.5/2./.6/1.9), RS-52 CHF 2 CF 3 CH 3 CH=CH 2, propylene flam flam r > yr ~ ~ ~2 58 January 27 HPAC Engineering

10 TABLE 2 (continued). Physical, safety, and environmental data for refrigerants (sorted by normal boiling point). Refrigerant Physical data Safety data Environmental data 43A 143a 42B 57A 47B 422A 44A 422C 421B 52 47A 48A 47C 422D 427A 47E 419A 29 R-29/22/218 (5./75./2.), 69-S CH 3 CF 3 R-125/29/22 (38./2./6.), HP81 R-125/143a (5./5.), AZ-5 R-23/32/134a (4.5/21.5/74.), FX-22 R-32/125/134a (1./7./2.), Klea 61 R-125/134a/6a (85.1/11.5/3.4), One Shot and Isceon MO79 R-32/125/143a/134a (1./33./36./21.), HX4 R-32/125/143a/134a (2./41./5./7.), FX-48B R-32/125/161 (15./34./51.), ZJU ZH1 R-125/143a/134a (44./52./4.), HP62 and FX-7 R-125/134a/6a (82./15./3.) R-125/134a (85./15.) R-22/115 (48.8/51.2) R-32/125/134a (2./4./4.), Klea 6 R-125/143a/22 (7./46./47.), FX-1 R-32/125/134a (23./25./52.), Klea 66 and Suva 9 R-125/134a/6a (65.1/31.5/3.4), Isceon MO29 R-32/125/143a/134a (15./25./1./5.), FX-1 R-32/125/134a (25./15./6.) R-32/125/134a/6 (1./42./45./3.) R-125/134a/E17 (77./19./4.), FX-9 CH 3 CH 2 CH 3, propane R-127/22/152a (3./95.5/1.5), G218C R-32/134a (3./7.) wff r yr ~ HPAC Engineering January 27 59

11 TABLE 2 (continued). Physical, safety, and environmental data for refrigerants (sorted by normal boiling point). Refrigerant Physical data Safety data Environmental data 418A 411B 422B A A 411A 47D 417A A 412A A B 41B 49A R-29/22/152a (1.5/96./2.5), THR3b R-127/22/152a (3./94./3.), G218B R-125/29/134a/E17/227ea (55.4/.6/34./2.5/7.5) R-125/134a/6a (55./42./3.) CHClF 2 R-125/134a (58./42.) R-22/12 (75./25.) R-125/134a/6a/6/61a (5.5/47./.9/1./.6), RS-44 R-125/134a/6/61a (5./47./2.7/.3) R-127/22/152a (1.5/87.5/11.), G218A R-717/E17 (6./4.), R723 R-32/125/134a (15./15./7.) R-125/134a/6 (46.6/5./3.4), Isceon MO59 and NU-22 CClF 2 CF 3 R-125/152a/227ea (4./5./55.), GHG-X7 R-32/134a/227ea (18.5/69.5/12.), THR3a R-22/218/142b (7./5./25.), Arcton TP5R R-161/218/13I1 (65.4/18.2/16.4) R-161/13I1 (8./2.) CH 3 CH 2 F, ethyl fluoride R-22/152a (82./18.) CF 3 CF 2 CF 3, perfluoropropane R-218/134a/6 (32.7/62.8/4.5), CM1 R-22/124/142b (65./25./1.), FX-57 R-125/134a/152a (35./4./25.), GHG-X8 R-22/152a/124 (61./11./28.), MP66 R-22/124/142b (6./25./15.), FX wff yr < January 27 HPAC Engineering

12 TABLE TABLE 2 (continued). 2 Physical, safety, and environmental data for for refrigerants (sorted (sorted by normal by normal boiling boiling point). point). Refrigerant Physical data Safety data Environmental data 5 413A A 41A 414B 45A 46A C A 41C 415B 134a 42A E17 423A 152a 416A 4 >> 13I1 4 >> 227ea R-12/152a (73.8/26.2) R-218/134a/6a (9./88./3.), Isceon MO49 NH 3, ammonia R-22/124/6a/142b (51./28.5/4./16.5), GHG-X4 R-22/152a/124 (53./13./34.), MP39 R-22/124/6a/142b (5./39./1.5/9.5), Hot Shot R-29/6a (5./5.), propane/isobutane R-22/152a/142b/C318 (45./7./5.5/42.5), G215 R-22/6a/142b (55./4./41.), Autofrost-X3 -CH 2 -CH 2 -CH 2 -, cyclopropane R-12/31 (78./22.) CCl 2 F 2 R-125/134a/6/61a (5.1/93./1.3/.6) R-22/152a/124 (33./15./52.), MP52 R-152a/6a (7./3.), C1 R-22/152a (25./75.), THR1b CH 2 FCF 3 R-134a/142b (88./12.) CH 3 -O-CH 3, DME R-134a/142b (8.6/19.4), RB-276 R-134a/227ea (52.5/47.5), Isceon 39TC CH 3 CHF 2 R-134a/124/6 (59./39.5/1.5), FR-12 R-12/114 (6./4.), R-4 (6/4) CF 3 I, trifluoroiodomethane R-12/114 (5./5.), R-4 (5/5) CF 3 CHFCF 3 R-31/114 (55.1/44.9) CHClFCF wff B2 d r ~ yr < ~ ~ HPAC Engineering January 27 61

13 TABLE 2 (continued). Physical, safety, and environmental data for refrigerants (sorted by normal boiling point). Refrigerant Physical data Safety data Environmental data 6a b C fa E134 E245cb fa ca a E347mmy b CH(CH 3 ) 2 -CH 3, isobutane SO 2, sulfur dioxide CH 3 CClF 2 CH 2 ClF R-6a/6 (5./5.), isobutane/butane CH 3 (NH 2 ), methylamine -CF 2 -CF 2 -CF 2 -CF 2 - CBrClF 2, halon 1211 CF 3 CH 2 CF 3 CH 3 -CH 2 -CH 2 -CH 3, butane CClF 2 CClF 2 CHF 2 -O-CHF 2 CH 3 -O-CF 2 -CF 3 CHCl 2 F CH 3 CH 2 Cl, ethyl chloride CHF 2 CH 2 CF 3 CH 3 -CH 2 (NH 2 ), ethylamine CCl 3 F CH 2 FCF 2 CHF 2 CHCl 2 CF 3 (CH 3 ) 2 CH-CH 2 -CH 3, isopentane CF 3 -CF(OCH 3 )-CF 3 HCOOCH 3, methyl formate CH 3 CCl 2 F R-61a/61 (37./63.), isopentane/pentane CH 3 -CH 2 -O-CH 2 -CH 3, ethyl ether CH 3 -CH 2 -CH 2 -CH 2 -CH 3, pentane R-61/62 (9.1/9.9), pentane/hexane CH 2 Cl 2, methylene chloride CCl 2 FCClF 2 CHCl=CHCl, dielene H 2 O, water C flam high high ^ B2 B yr ~ ~ ~ ~ ~2 ~2 ~ <1 = normal boiling point; = critical temperature; = critical pressure; = occupational exposure limit in PPM by volume TWA, unless preceded by "C" for Ceiling, such as the ACGIH Threshold Limit Value (TLV-TWA), AIHA Workplace Environmental Exposure Level (WEEL), OSHA Permissible Exposure Limit (PEL), or a consistent limit (see text); = lower flammability limit (% by volume in air), flam indicates flammable but the is unknown and wff signifies that the worst case of fractionation may become flammable; = heat of combustion; ODP = ozone depletion potential (semi-empirical); = global warming potential (for 1-yr integration). Suffixes to safety classifications indicate recommended changes that are not final yet ( d for deletion and r for revision or addition) or classifications assigned as provisional ( p ); d alone indicates that a prior classification was deleted (withdrawn). Data sources are identified in the Refrigerant Database; verify the data and associated limitations in those sources before use. Copyright 26 James M. Calm, Engineering Consultant 62 January 27 HPAC Engineering

14 Continued from Page 52 consensus scientific assessments. 8,9,1 The s shown for blends are calculated, -weighted averages. values can be calculated for any desired integration period, commonly referred to as the integration time horizon (ITH). Short ITH periods emphasize immediate effects, but overlook later impacts, while long ITH periods incorporate more of the later effects. The most common values, including those cited herein, are for an ITH of 1 years. These values account only for the direct effect of refrigerants (or other substances) upon release as greenhouse gases. A variant dubbed an indirect gauges the impacts of other atmospheric chemicals created or destroyed by released refrigerants. Examples include decomposition and catalyzed reaction products that act as greenhouse gases. Another example is ozone destruction by released refrigerants, hence removal of a potent greenhouse gas. Accordingly, indirect values can be positive or negative numerically. A positive indicates radiative forcing, or a global warming effect. A negative signifies negative radiative forcing, or a global cooling effect. Summing direct and indirect s yields net s, which also could be positive or for some ozonedepleting substances negative. Indirect s should not be confused with the indirect effect that accounts for action of energy-related emissions, as part of total equivalent warming impact (TEWI) and similar analyses. Except for R-5 (methane), the values shown in tables 1 and 2 are direct rather than net s for consistency with international assessments, pending refinement of the indirect data. The values shown as ~2 for hydrocarbons reflect uncertainty in calculations, for which there is no scientific consensus at this time. The approximation shown is within the range of estimates. Further study, using three-dimensional (3D) models for a range of release scenarios, is needed to determine representative FIGURE 2. Ozone depletion potential (ODP) contrasted to global warming potential () for key refrigerants (brown and orange shading indicate semi-empirical and modeled ODPs, respectively). CFCs generally have high ODP and. HCFCs generally have much lower ODP and. HFCs offer near-zero ODP, but some have very high s. Copyright 26 James M. Calm s for chemicals with very short atmospheric lifetimes, including the saturated and unsaturated hydrocarbons among others. The atmospheric lifetime (τ atm ) impacts both the ODP and, but those metrics also reflect separate chemical properties and other atmospheric data. The τ atm, ODP, and all should be as low as possible for selected refrigerants, and they should be considered along with performance, safety, and both chemical and thermal stability. 1 Figure 2 depicts the ODPs and s for common refrigerants. No inference should be drawn that a unit of ODP equals a unit of ; they are dissimilar metrics and there is no direct way to equate them. The intent of the figure is to enable quick identification of which refrigerants are high in both ODP and, low in one or the other, or low in both. References 8, 9, 1, and 11 provide further information on these indices. ODP AND DATA FOR REGULATORY AND REPORTING PURPOSES The ODP and data presented in tables 1 and 2 reflect the latest consensus determinations of potential impacts. However, the reduction requirements and allocations under the Montreal Protocol (and many national regulations pursuant to it) use older, adopted ODP values. The ODP values listed in the annexes to the Montreal Protocol, for example, have not been updated since 1987 for chlorofluorocarbons (CFCs) and 1992 for hydrochlorofluorocarbons (HCFCs). 9 A note in the Protocol indicates that the values are estimates based on existing knowledge and will be reviewed and revised periodically, but that has not happened yet. Similarly, emission reporting pursuant to the Kyoto Protocol is based on data from an earlier assessment, 12 rather than more recent scientific findings. Tables 3 and 4 contrast the regulatory (or reporting) ODP and values to the latest data from international, scientific, consensus assessments. While the scientific data logically would precede the regulatory data, the order is shown as reversed because the scientific data were updated subsequently, while the regulatory values were not. HPAC Engineering January 27 63

15 ENVIRONMENTAL DATA DIFFERENCES The values for τ atm, ODP, and change as understanding of atmospheric science expands and the chemical kinetics involved become better understood. They also change when newer measurements are made. These factors have driven periodic reviews and consensus assessments by the scientific community. The τ atm, ODP, and values shown in tables 1 and 2 reflect data from the latest international assessments. 8,9,1 The tables include additional data from selected scientific publications for refrigerants not addressed in these assessments. The data indicated for blends are calculated values based on the components and nominal formulations. REFERENCES 1) J.M. Calm and D.A. Didion, Trade-Offs in Refrigerant Selections Past, Present, and Future, Refrigerants for the 21st Century (proceedings of the ASHRAE/NIST Conference, Gaithersburg, MD, October 1997), ASHRAE, Atlanta, GA, USA, 1997; International Journal of Refrigeration (IJR), 21(4):38-321, June ) J.M. Calm, Property, Safety, and Environmental Data for Alternative Refrigerants, Proceedings of the Earth Technologies Forum (Washington, DC, USA), Alliance for Responsible Policy, Arlington, VA, USA, , October ) J.M. Calm and G.C. Hourahan, Physical, Safety, and Environmental Data for Refrigerants, Heating/Piping/ AirConditioning Engineering, 71(8):27-33, August ) J.M. Calm and G.C. Hourahan, Refrigerant Data Summary, Engineered Systems, 18(11):74-88, November 21. 5) Designation and Safety Classification of Refrigerants, ANSI/ASHRAE Standard 34-24, ASHRAE, Atlanta, GA, USA, 24, and both published and pending addenda thereto, ) R.D. Loss for the International Union of Pure and Applied Chemistry TABLE 3. Regulatory and consensus scientific ODP for BFC, CFC, and HCFC refrigerants. ODP Refrigerant Regulatory 11 Modeled 12 Semi-empirical 8,9, b (IUPAC) Commission on Atomic Weights and Isotopic Abundances, Atomic Weights of the Elements 21 (IUPAC Technical Report), Pure and Applied Chemistry, 75(8): , August 23 and private communications on the 25 updates in press. 7) J.M. Calm and P.A. Domanski, R- 22 Replacement Status, ASHRAE Journal, 46(8):29-39, August 24; erratum, TABLE 4. Regulatory and consensus scientific for 1-year integration of HFC and PFC refrigerants. Refrigerant Regulatory 13 Scientific 8,9, a 143a 152a ea 236ea 236fa 245fa C ,5 11,7 65 9,2 2,8 1,3 3,8 14 7, 2,9 6,3 8,7 1 *R-161 is from Reference 13 7,39 14, ,2 3,5 1,43 4, * 8,83 3,22 1,37 9,81 1,3 1, (1):8, October 24. 8) World Meteorological Organization (WMO), Scientific Assessment of Ozone Depletion: 26, WMO, Geneva, Switzerland, in press with expected publication in March 27. 9) Intergovernmental Panel on Climate Change (IPCC) and the Technology and Economic Assessment Panel (TEAP), Safeguarding the Ozone Layer and the Global Climate System: Issues Related to Hydrofluorocarbons and Perfluorocarbons, WMO, Geneva, Switzerland, and the United Nations Environment Programme (UNEP) Ozone Secretariat, Nairobi, Kenya, 25. 1) Intergovernmental Panel on Climate Change (IPCC), Climate Change 21: The Scientific Basis Contribution of Working Group I to the IPCC Third Assessment Report, Cambridge University Press, Cambridge, UK, ) UNEP, Handbook for the International Treaties for the Protection of the Ozone Layer (Seventh Edition), UNEP Ozone Secretariat, Nairobi, Kenya, ) World Meteorological Organization (WMO), Scientific Assessment of Ozone Depletion: 22, report 47, WMO Global Ozone Research and Monitoring Project, Geneva, Switzerland, March ) Intergovernmental Panel on Climate Change (IPCC), Climate Change 1995 Contribution of Working Group I to the IPCC Second Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, Copyright 27 James M. Calm and Glenn C. Hourahan 64 January 27 HPAC Engineering