CA2232674A1 - Drop-in substitutes for dichlorodifluoromethane refrigerant - Google Patents

Abstract

A group of known refrigerants, (R-227ea, R-124, R-134a, R-143a, R-125, R-E125, R-E143a, R-E227ca2, R-245cb, R-600a, R-142b, R-22, R-290, R-E170, R-1270, R-1216, R-218, R-C318, R-C270) that may be combined in novel ways to produce several excellent "drop-in" substitutes for refrigerants R-12 or R-500. The performance of the preferred "drop-in" substitutes for R-12 or R-500 of the present invention often exceeds that of the refrigerant being replaced, while maintaining acceptable oil circulation with existing mineral oils used in R-12 or R-500 refrigeration and air conditioning systems.

Description

WO 97/11138 PCTrUS96/14882 DROP-IN SUBSTITUTES FOR
DICHLORODIFL.UOROMETHANE
REFRIGERANT
The present invention relates to refrigerants generally, and more specifically to a mixture of refrigerants that may be substituted for the environmentally dal"agi,lg refrigerant dichlorodifluoromethane (R-12).
BACKGROUND ~F THE INVENTION

In order to provide a more compact format for identifying mixtures of refrigerants in the following discl Issions, mixtures of refrigerants will be listed 0 in the form of:

which represents a mixture of refrigerants (fluids) R-ABC, R-DEF, and R-GHI
where N0, N1, and N2 are the weight percentages of each component refrigerant fluid, and N0+N1+N2 = 100; or in the form of:
R-ABC/DEF/GHI N0-N0'/N1-N1'/N2-N2' which is similar, but specifies ranges of the weight percentages each of the component refrigerant fluids, with the total of the weight percentages being 1 00 percent.

Zeotropic (nonazeotropic) mixtures of refrigerants will change composition if they are allowed to leak as vapor phase from a container containing all romponents of the refrigerant mixture in both vapor and liquid phases. Single component and azeotropic mixtures of refrigerants do not change composition appreciably from vapor leakage. Single component and azeotropic mixtures of refrigerants have only one boiling point temperature for a given pressure, provided the refrigerant exists as both liquid and vapor states in the container. Zeotropic mixtures of refrigerants will boil over a range of temperatures at a given pressure. As the temperature is raised, the W O 97/11138 PCT~US96/14882 point at which the first bubbles appear (constant pressure) in the liquid is known as the "bubble point," which is roughly analogous to the boiling point of a single component or an azeotropic mixture. Starting in a vapor phase and lowering the temperature (at a constant pressure) to the point where the first droplet of liquid forms defines what is known as the "dew point" of the mixture of refrigerants. The difference between the bubble point temperature and the dew point temperature is known as the temperature "glide". A pressure gauge connected to a cylinder containing a zeotropic mixture of refrigerants will read the bubble point pressure for the corresponding temperature of the refrigerant mixture.

Under the Montreal Protocol, as amended, United States laws (1990 Clean Air Act), and U.S. Environmental Protection Agency rules, the production and importing of R-12 ended on December 31, 1995. Additionally, only 15% of the 1989 baseline amounts of chlorinated fluGrocarl,ons (CFCs) was allowed to be produced or imported into the U.S. during the year 1995 adjusted on an ozone depletion factor basis. R-12 is the major share of that production.

With the effective date of the ban on U.S. R-12 production and importing having passed (December 31, 1995), one industry option has been to retrofit R-12 refrigeration or air condilio"i"g systems, both stationary and aulorr,.live, to R-134a (tetrafluoroethane). The mineral oils used in R-12 systems are completely immiscible in R-134a, however, as the industry has therefore developed new oils, which are either polyalkylene glycol (PAG) based (for automotive) or polyol ester (POE) based (stationary refrigeration 25 and some automotive retrofit).

While PAG oils are good lubricants, and are miscible in R-134a at typical evapora~or temperatures, they have two main problems. First, most PAG oils cannot tolerate even minute traces of residual chlorides that remain in the R-12 refrigeration or air conditioning systems that have been purged of R-12. These chlorides are dissolved in the small amount of mineral oils which cannot be flushed out or are in codli"gs on the inside of aluminum piping (aluminum chloride from previous R-12) or are dissolved in rubber hoses. The presence of chlorides greatly acceleral:es the breakdown of most PAG oils.

It has been reported in the literature that test systems that were flushed with R-11 (trichlorofluoromethane) and then r~l~ur,Lled to PAG oil and R-134a, sustained cald:jL,u~)hic compr~ssor failures within one week due to oil breakdown. R-11 has a greater affect on PAG oil breakdown than does R-l0 12. It was common practice in the automotive air conditioning serviceindustry, into the early 1990s, to flush R-12 systems with R-11 to remove contaminates. The traces of R-11 remaining do not interfere with R-12 operation, but could cause premature lailures if R-12 systems are ever filL~d to R-134a and PAG oils.

The second main problem with PAG oils is that PAG oils are in the order of 100 times more hydroscopic (absorb moisture) than are R-12 mineral oils. During assembly, service, or after an accident, automotive R-134a systems may be exposed to atmospheric moisture which will be absorbed into the PAG oil. Extreme care is therefore required during servicing of PAG oil systems to prevent exposure to atmospheric moisture, especially in humid clin ,alt:s.

The stationary refrigeration industry has overwhelmingly chosen POE-based oils for R-134a systems, for both new systems and those l~ urilled from R-12. POE oils can tolerate residual chlorides much betterthan PAG
oils, however POE oils have problems also. POE oils are on the order of 10 times more hydroscopic than are R-12 mineral oils. POE oils, in general, do not have as good lubricities as do the PAG and mineral oils. Steel is a known catalyst that facililales the breakdown of most POE oils at the higher temperatures encountered in refrigeration systems. The industry has had to develop passivators and additive packages for POE oils to try to counter this problem. Moisture and other contal"i"~les may cause the POE oils to break down into their constituent fatty acids and alcohols.

Many industry R-134a retrofit procedures for R-12 stationary refrigeration and air conditioning systems call for 3 to 5 changes of the compressor oil (to a POE) in order to reduce the residual mineral oil to below about 1 percent to about 5 percent by volume. Most small to medium sized (up to 10 tons in capacity) hermetic compressors in R-12 equipment do not have oil drains. Therefore, the compressor must often be removed and the oil dumped out up to 5 times for a retrofit to R-134a. This entails unbra~ing the low and high side refrigeration pipes from the col"pr~ssor and rebrazing them up to 5 times. The brazing temperature is about 1100 degrees Fahrenheit.
Service technicians often do not go to the trouble to bleed a relatively inert gas such as dry nitrogen or C02 through the piping during brazing operations. Brazing temperatures cause the copper piping to oxidize on the inside forming "scale" which flakes off and adds to the conlar"i"aLion of the system. The oil coating the inside of the piping breaks down and carbonizes, adding more contaminates. Even worse, if refrigerant vapors are present in the pipes during brazing, they decGr"pose into hydrochloric and hydrofluoric acids, which greatly add to system contamination and premature failure.
Finally, the physical operation of removing the compressor 5 times, and inverting it to remove oil, can allow metal flakes and other sludge which have accumulated in the bottom of the compressor oil sump to break loose and end up on the top of the inside of the compressor shell. Upon reinstalling the compressor this sludge and metal flakes may drop onto the top of the compressor and get into motor windings (causing shorts and motor burnouts) or get into the intake valves and cause mechanical problems (seized compressor).

W O 97/11138 PCT~US96/14882 There have been several repor~s that both POE and PAG oils causing skin rashes or burns to service technicians. This has necessil~led additional safety procedures, such as wearing gloves, when handling these oils. Unless a hermetic compressor motor burnout has occurred, R-12 mineral oils have not caused skin rashes and burns to service technicians. A hermetic compressor motor burnout causes sorne of the refrigerant to decompose into hydrofluoric and hydrochloric (if the refrigerant contains chlorine atoms) acids, and may cause skin burns no matter what oii is used.
Some co""l~ressor~ built for R-12 and ,~I,urillecl to R-134a with POE
10 oils have been reported by compressor manufacturers to fail from lubrication problems c~used by the lack of the "roar";.,g" of the POE oils in the compressor crankcase. Some compressor designs relied on the fact that mineral oils and R-12 generated foaming in the compressor crankcase in order for the oil to reach and lubricate certain parts of the compressor. New co,n,uressors designed for R-134a and POE oils use other means to make sure all the parts are properly lubricated.
Compressors manufactured for R-12 and mineral oil use often were constructed with a paraffin based wax coating on the motor windings as an aid to building the motor without breaking the wire during the motor winding phase of the construction. When l~llurilled to R-134a and POE oils, the par~rri" would son ~li" ,es come off the windings, and not dissolve in the R-134a refrigerant and POE oils, and circ:ulate through the system as solids and plug up the refrigerant metering device, usually a capillary tube, causing the system to fail. R-12 (or a substitute with adequate mineral oil miscibility) andmineral oil, just dissolve the pieces of paraffn wax which come offthe motor windings and t~.erefore do not clog the refrigerant metering device.

Finally, the low critical temperature of R-134a (213.9 degrees Fahrenheit) verses the critical temperature of R-12 (233.2 degrees Fahrenheit) can cause abnormally high head pressures in hot ambient conditions in systems designed for R-12. For automotive applications, stopped traffic or hot cli"~ales can cause a reduction in R-134a performance.
Systems designed for R-134a often increase the size of the condenser about 50 percent over the size similarly designed R-12 system condenser.
Stationary systems, such as vending machines, now lel,~ril~ed to R-134a may see high head pressure and low performance problems when the condenser becomes slightly fouled by dirt and dust. R-12 systems can run much longer between cleanings to remove dust and dirt from the condenser o than similar systems converted to R-134a.

R-406A is a known ternary mixture of refrigerants, consisting of isobutane (R-600a), chlorodifluoroethane (R-142b), and chlorodifluoromethane (R-22) that provides a "drop-in" substitute for dichlorodifluorol"~:ll,ane (R-12) refrigerant. R406 is described in U.S.
Patent Nos. 5,151,207 and 5,214,929, the clisclosures of which are incorporated herein by reference.
In addition to being a suitable "drop-in" substitute for R-12, R-406A
has been successrully used as a i'drop-in" substitute for refrigerant R-500 (azeotropic mixture of R-12 and R-152a with weight percentages of 73.8 and 26.2, lespe.;li~,~ely) in many instances. R-152a is 1,1-difluoroethane.

Refrigeration systems with refrigerant metering devices consisting of a capillaly tube or a fixed orifice have had excellent results with R-406A as a "drop-in" substitute. Some R-500 systems with "thermostatic expansion valves" (TEVs), have needed the "power head" of the expansion valve changed to an R-12 head, while others have performed satisfactory.

Several other attempts have been made to create the ideal "drop-in"
substitute for R-12. Some do not return mineral oil to the compressor properly at temperatures of desired operation (i.e., Forane~ FX-56 (R-W O 97/11138 PCT~US96/14882 124/142b/22 25/15/60) also known as R409A, U.S. Patent No. 5,188,749;
and FRIGCTM FR-12T~ (R-600/124/134a 2139159), U.S. Patent No. 5,425,890).
Changing the compressor oil from mineral oil to alkylbenzene oil will often ~ correct the oii return problems, but now an oil change is necessary and the 5 refrigerant is no longer a "drop-in" substitute for R-12.
Some ~LL~r"pls have provided temperature-pressure curves which are not always suitable for operation of R-12 equipment. The Forane~ FX-56 refrigerant temperature-pressure curve is too high, which results in eYcessive head pressures, refrigerant breakdown and compressor failures in many l0 instances. See Figure 1 for the Forane~ FX-56 temperature-pressure chart.
FRIGCT~ FR-12TM, on the other hand, has a temperature-pressure curve which is too low, which results in low system capacities, and c~l~ses problems if system low pressure cut out controls are not replaced or adjusted. See Figure 1 for the FRIGCTM FR-12TM temperature-pressure chart. FRIGCTM FR-12TM used in an automotive air conditioning system should produce suctionside pressures of about 18 to about 23 gauge pressure (PSIG), whereas R-12 would produce about 28 to about 32 PSIG. This causes the low pressure controls to prematurely open, falsely sensing low-on-charge or too cold conditions. Once opened, the compressor clutch disengages, stopping the compressor, and the system equalizes in pressure, and restarts. This results in poor capacilies, and excessive clutch wear from cycling every few seconds.
Automotive variable displacement con ,pressors, such as the GM V-5. try to maintain a constant suction pressure, usually about 28 to about 30 PSIG for capacity control. The lower than R-12 temperature-pressure curve of FRIGCT~~ FR-12TM fools these compressors into operating at a much lower ~ displacement than for R-12 under given load conditions, thus greatly reducing capacities (in the order of 50 percent reduction or more). If a large amount of FRIGCT~ FR-12TM (3 pounds or more), is allowed to vapor leak under ambient temperatures of about 10 degrees to about 25 degrees Fahrenheit, the remaining mixture may possibly first go weakly nal"",able then highly flal"mable near the very end of the leak out (90 weight percent or more of the mass has leaked). The boiling point of their highest boiling point component, R-600 (n-butane), is 31.03 degrees Fahrenheit, while their next lower boiling point component is R-124, with a boiling point of 8.26 degrees Fahrenheit.
These foregoing and additional known refrigerant mixtures are summarized below. Some are disclQsecl in research papers and others in U.S. Patents, while still others are commercial products on the market.

o Has poor mineral oil miscibility. See U.S. Patent no. 4,303,536.

Almost nonexistant mineral oil miscibility, and the glide is too high.

R-124/142b/22 25/15/60 This is Elf Atochem Forane~ FX-56, or R409A. See U.S. Patent No.
5,188,749. Forane~ FX-56 has poor mineral oil miscibility, and the temperature-pressure curve is too high. lt is som~lin~es claimed to be an R-12 "drop-in", other times claimed to be near "drop-in" requiring changing oil toalkylbenzene tvpe to assure miscil,ilily. Six hours of operation in the oil miscibility test stand descl il,ed in Appendix A, callsed moderate oil logging in the evaporator and suction line at an evaporator temperature of about 10 degrees Fahrenheit using Suniso 3GS (150 viscosity) mineral oil, standard for systems of this type. Severe oil logging occurred around -20 degrees Fahrenheit, wil:h two phase (oil and liquid refrigerant) and "milky" solutions observed in the evaporator. Pure R-22 performed much the same way. The "milky" solution is caused by an immiscibile "dispersion" of oil and liquid refrigerant. After severe oil logging from Forane(~ FX-56 at about -20 degrees Fahrenheit, the Forane~ FX-56 was removed, and the oil miscibility test stand was charged with the refrigerant mixture later described in Example 1.
-Two hours of operation with Exampie 1 returned almost all the oil to the compressor, operating at about -30 degrees Fahrenheit.

R-22/124/142b 65125110 This is Elf Atochem Forane~ FX-57, or R409B. This mixture will have even less miscibility in mineral oil than Foralle(~ FX-56. Forane(~ FX-57 will also have an even higher temperature-pre.ssure curve than Forane~ FX-56 due to more R-22 component and less R-142b component.
R-124/152al22 24/13153 This is DuPont SUVA~ MP-39, or R-401A. See U.S. Patent No. 4,810,403.
o R401A has poor miscibility in mineral oils. DuPont reco"llllends at least 80 volume percent of the compressor oil be changed to alkylbenzene type to assure miscibility. R401A works fine provided compressor oil is changed.
R-124/152a/22 61/11/28 This is DuPont SUVA MP-66, or R-401 B. The same comments for R401A
apply here as well.
R-124/152al22 33/15132 This is DuPont SUVA~ MP-52, or R401C. The same comments for R401A
apply here as well.

R-600/124/134a 2139159 This is Intermagnetics General Corporation (IGC) FRIGCTM FR-12TM. See U.S. Patent No. 5,425,890. FRIGCTM FR-12TM claims to be a "drop-in" for R-12, but the temperature-pressure curve is about 8 degrees Fahrenheit too low at evaporator temperatures (32 degrees Fahrenheit) in automotive air ~ conditioning systems, causing low capacity, excessive compressor cycling and rapidlywearing outcompressorclutches. Excessive clutch cycling may be eliminated by replacing low pressure cutout switches. FRIGCT~ FR-12 has poor mineral oil miscibility. FRIGCTM FR-12TM may become weakly or WO 97/11138 PCT~US96/14882 highly fla"""able due to vapor leakage under cold (about 10 to about 25 degrees Fahrenheit) ambient conditions. However, the amount of nan,r"able mass remaining would be small, in the order of 10 weight percent of the original system charge.
R-221152a/142b/C318 45/715.5142.5 This is China Sun G2015, or R-405A. R405A has very marginal mineral oil miscibility, ail components are totally immiscibile with mineral oil except for R-142b and R-22, which are poor. The R-C318 component is expensive and the R405A mixture was banned (listed as SNAP unacceptable) by the US EPA
due to global warming concerns of the R-C318 component, which does not easily break down in the dl"~osphere, even after several thousand years.
R-221218/142b 7015/25 This is R-412A. Although intended as a "drop-in" substih~te for R-500, it still has a temperature-pressure curve which is too high for most uses and limited mineral oil miscibility, but slightly better miscibility than Forane~ FX-56 and Forane~ FX-57 due to more R-142b component. R-218 component is a perfluorinated fluorocarbon with a high global war",i"y potential and a very long atmospheric lifetime, and like R-C318, the US EPA is not approving these compounds for refrigerants.

R-2901600a 60/40 Excellent refrigerant, with excellent oil miscibility. Low cost of components.
The problem is the extreme nal"l"ability of all components (all hydrocarbons).
Blends similar to this have been around a number of years. OZ-12, HC-12a, and ES-12r are tradenames of some similar hydrocarbon blends. At least 14 states have banned the use of hydrocarbon blends for motor vehicle air conditioning along with a Federal ban by the US EPA, which took effect on 7/1 4195.

WO 97/11138 PCT~US96/14882 This is Bromodifluoromethane, or Great Lakes Chemical FM-100. The temperature-pressure curve is too low. R-22B1 boils at 4.2 degrees ~ Fahrenheit (R-12 boils at-21.6 degrees Fahrenheit). R-22B1 contains a 5 bromine atom, causing a sig-~iricant ozone depletion potential, therefore the EPA will not approve its use for refrigerant. R-22B1 has excellent mineral oil miscibility.

R-134a 100 R-134a has complete immiscibility in rnineral oil, making it not suitable for lO most R-12 applications. However, some systems, such as some household refrigerators, may successrully operate using R-134a in mineral oil if the pipe sizes are small enough to generate hiyh enough gas velocities to drag the mineral oil around the r~rli~erdlion circuit. The compressor is usually located downhill from the evaporator, further ~-,i"i",i,ing oil return problems with an 15 i"""iscible oil/refrigerant mixture.

R-152a/22B1 77/23 Good miscibility with mineral oil, but the temperature-pressure curve is too low. Both components have boiling points well above that of R-12. This mixture may be flammable if vapor leaked at temperatures below about 0 degrees Fahrenheit. R-22B1 is not approved by the US EPA for refrigerant use due to high ozone depletion potential.

R-227ea 1 00 No miscibility with mineral oil and the temperature-pressure curve is much too low.
R-1 ~2a/227ea 80/20 No miscibility with mineral oil and the temperature-pressure curve is lower than R-12, causing around a 10 percent reduction in capacity in unmodified W O 97/11138 PCT~US96/14882 systems. This mixture will be flammable, especially when leaking at colder temperatures, below about 0 degrees Fahrenheit.

R-152a/227ea 50/60 No miscibility with mineral oil and the temperature-pressure curve is lower than R-12, causing around a 12 percent to 15 percent reduction in capacity in unmodified systems. This mixture may be nan,rl)able, especiallywhen leaking at colder temperatures, below about 0 degrees Fahrenheit.

R-290/227ea 50/50 Good miscibility with mineral oil. Pressure-temperature curve is much too o high, almost as high R-22. This mixture will be highly flammable.
R-152a 100 Flar"l.,able, but not as bad as propane (R-290). No miscibility with mineral oil. Temperature-pressure curve is too low, causing around a 10 percent reduction in capacily.

R-290/227ea 10/90 Good temperature-pressure curve, and good mineral oil miscibility. This blend will be flammable when vapor leaked at temperatures beiow about 0 degrees Fahrenheit and may be weakly n~r"",able when leaked at higher temperatures. This mixture has a large mass fraction in the higher boiling cGlllponent (R-227ea), which on some systems may cause unwanted liquid refrigerant return (slugging) to the compressor since there will be a large fraction of the boiling liquid near the exit end of the evaporator. This narrowsthe margins for charging and suction superheat setup on refrigeration systems.

R-227ea/E170 70/30 R-E170 is dimethyl ether. This mixture has good mineral oil miscibility, but the temperature-pressure curve is too low. This mixture may be flammable, W O 97/11138 PCTnUS96~48~2 especially when vapor leaking at colder temperatures such as below about 0 degrees Fahrenheit.

R-227ea/600a 75/25 Good mineral oil miscibility but the temperature-pressure curve is way too s low. This mixture might exhibit a region of nalllll,ability when vapor leaked in a temperature range of about 0 degree!s Fahrenheit and about 100 degrees Fal~renheit.

R-1 52a/227ea 20/80 No mineral oil miscibility and the temperature-pressure curve is too low. This o mixture is probably non flammable or plossibly weakly flammable over limited tegions.

R-1 52a/1311 25/75 R-1311 is trifluoroiodom~ll,ane (CF31). Pressure-temperature curve is too low.
This mixture has a boiling point of about -8.5 degrees Fahrenheit. There are S also concerns of the stability of R-1311 due to the weakness of the iodine bond. The inventors of this mixture claimed that light broke down R-1311 and c~used refrigerant sight glasses to show purple in about two weeks. The inventors also claimed an extremely his.3h ozone depletion potential for R-1311 but an almost zero ozone depletion pol:ential after release into the ~L"~osphere after a small number of days (less than a week) due to the breakdown of the CF31 molecule. Toxicity of CF31 is not well established yet.

R-1 52a/227ea 25175 No misicibility in mineral oil. The boiling point of -5.2 degrees Fahrenheit indicates a temperature-pressure curve which is too low. This mixture may also exhibit regions of flammability when vapor leaked at colder temperatures below about 10 degrees Fahrenheit.

W O97/11138 PCT~US96/14882 R-218/134a/600a 9188/3 This is lsceon 49. Based on a published bubble point of 99 PSIA, the temperature-pressure curve may be a little high, but useable. R-218, a PFC, is now banned by the US EPA for use in refrigerants due to high global 5 warming potential and extremely long atmospheric lir~til"es in the thousands of years. Mineral oil miscibility is very poor.

R-22/142b 40/60 Temperature-pressure curve is too low (R-22/142b 55/45 is much closer).
Vapor leaking may cause mixture to become weakly flammable, but with no 10 flashpoint. Mineral oil miscibility is poor, but may be useable in high temperature equipment (35 degrees Fahrenheit and higher) for the evaporator temperatures. Mineral oil miscibility is similar to (slightly better than) R-22.

R~134a/600a 80/20 Proposed by Electrolux. Good mineral oil miscibility, but the temperature-pressure curve appears to be slightly high from computer simulations (REFPROP V4.0) and almost azeotropic behavior is exhibited. This mixture appears to have a simulated boiling point about -28 degrees Fahrenheit. lt may be a useable suhstitute for R-500 though. Some azeotropes exhibit a boiling point outside the range (usually lower) of the boiling points of the individual components. The simulated azeotropy point is R-134a/600a 77.83/22.17 for this mixture. An a~ec l, ~,pic mixture behaves, for practical purposes over the temperatures of interest, as a single component refrigerant fluid. During the boiling of the liquid phase of the mixture, all components evaporate at equal rates and fractionation does not occur. The glide is essentially zero. The simulated critical temperature is 211.0 degrees Fahrenheit, which is lower than that of R-134a, which will cause high head pressures in hot environments. This mixture will be flammable.

W O 97/11138 PCT~US96/14882 R-134a/152a 85/15 Boiling points of both components are lower than R-12. Temperature-pressure curve will be slightly too low at evaporator temperatures, but it closely matches that of R-134a (by computer simulation). Azeotropic behavior is observed from simulation, writh boiling point of -15.62 degrees Fahrenheit which is practically the same as R-134a. No miscibility with mineral oil. This mixture should be norllnan""able orweakly n~mr"able at worst at temperatures of interest, but may be na" " ,lable under new strict US
nar"r"~bility standards such as Under~riters Laboratories (UL) 2182 where testing is currently performed at 100 degrees Centigrade.

R-134a/600a 95/5 Mediocre miscibility in mineral oils. The temperature-pressure curve is good (near azeotrope). This mixture should work fine in systems where the com,ur~ssor does very little "oil pumping" (circulating oil in the refrigerant circuit), such as some household refrigerators. Other systems, especially automotive air conditioner compressors and commercial systems can circulate as much as 10 or 15 percent by volume of oil with the refrigerant.
This mixture will not be able to return all the oil under those conditions. R-134a has zero oii miscibility by itself, and the addition of a small percentage of a hydrocarbon such as R-600a will not cause the R-134a itself to carry any oil and all the oil will have to be carried by the hydrocarbon. Flan""ability cGnsLI~il lLs limit the amount of the hydrocarbon component to around 5 percent.

Five pounds of the R-134a/600a 95/5 mixture were made up for test purposes. About two pounds were charged into the oil miscibility test stand described in Appendix A. Running the evaporator at about -40 degrees Fahrenheit for about 3 hours, caused severe oil return problems, with oil logging observed, and the crankcase oil level dropping. The evaporator temperature was raised to about 5 degrees Fahrenheit by partially closing W O 97/11138 PCTrUS96/14882 the manual evaporator pressure regulator valve, and oil continued to become trapped in the evaporator with further observed dropping of the crankcase oil level to near the bottom of the sight glass (compressor running, oil level at top of sight glass at start of run). No oil return was observed at either temperature in the overhead suction line sight glass.

The evaporator temperature was then raised to about 30 degrees Fahrenheit, by the application of about 2500 watts of electrical power to the evaporator. A limited amount of oil was now observed returning to the compressor, as small (amount 1 mm in size) entrained "balls" in the suction l0 gas flow. It was not creeping along the walls of the suction pipes as is usually the case with a mineral oil miscibile refrigerant. It can therefore be concluded, that the addition of about 5 percent weight of isobutane to R-134a, provides only very limited mineral oil return capability, for high temperature systems, and is essentially useless for returning oil at lower temperatures of operation. The oil used was Suniso 3GS (150 viscosity).

Since aulor"olive compressor oil has a much higher viscosity than do most oils used for sldliGnary refrigeration (automotive is usually 525 viscosity), the increase in oil return, due to the addition of the isobutane forautomotive air conditioning, is expected to be almost nil.
The R-134a/600a 95/5 mixture should be nonflammable at normal temperatures of operation, but may be flammable under new strict US
flammability standards such as Underwriters Labs (UL) 2182 where testing is currently performed at 100 degrees Centigrade.
R-218/152a 83.5/16.5 Claims to replace R-12, R-502, and R-22. This composition calculates (with REFPROP V4.0) computer simulation to have a temperature-pressure curve much too high for R-12 replacement. It is closer to R-22. Even if the R-218 weight percentage were drastically reduced and the R-152a increased to W O 97/11138 PCTrUS96/14882 achieve a good temperature-pressure curve for R-12, this mixture would still have no mineral oil miscibiiity. The R-218 is currently banned for refrigerants by the US EPA due to high global warming potential and long atmospheric lifetime.
R-22/142b/600a 5514114 This is R-406A, and it has performed satisfactory in the field as a "drop-in"
substitute for R-12, and it is no"n~"""able (after fractionating from vapor leaking) when used by those skilled in the art of refrigeration at normal temperatures of operation of R-12 refrigeration and air conditioning systems.
0 Safety testing by several independent labs has verified this. However, new very strict flammability regulations are CGllli.l9 into place in the Unites States, while other countries (many in Europe) are changing over to highly flammable hydrocarbon mixtures of refrigerants. Many refrigerant fluids will be essentially nonflammable at normal temperatures of operation, but may fail a ndr"r"ability test that specifies an a,liricially high temperature of operation such as 212 degrees Fahrenheit or higher. R-406A falls into this category.
It is clear from the foregoing discussion that a "drop-in" substitute for R-12, which does not require oil changes and has a higher critical temperature than R-134a, would result in many benefits.

The automotive air conditioning market for a R-12 sl~hstit~te in the U.S.
is huge with an esLi",dLed 125 million cars presently left using R-12. It is imperative that "drop-in" R-12 substitul:es continue to be developed and used to prevent the costly and premature replacement of billions of doliars worth of refrigeration and air conditioning equipment.

WO 97/11138 PCT~US96/14882 SUMMARY OF THE INVENTION

In sumrnary, l have discovered a group of refrigerant fluids. which are listed in Tables 1-3, which may be combined in novel ways to produce several excellent "drop-in" substitlltes for refrigerants R-12 or R-500. The 5 performance of the preferred "drop-in" substitutes for R-12 or R-500 of the present invention often exceeds that of the refrigerant being replaced, while maintaining acceptable oil circulation with existing mineral oils used in R-12 or R-500 refrigeration and air conditioning systems. For the purposes of this invention, "refrigeration and air condilioning systems" will be referred to l0 collectively as "refrigeration systems." Also, for the purposes of this invention, "R-500 refrigeration systems" will be considered to be included within the phrase"dichlorodifluoromethane refrigeration systems."

One embodiment of the present invention is an improvement to the novel ternary mixture of refrigerants described in U.S. Patent No. 5,151,207, which is a "drop-in" substitute for R-12, but unlike R-12, provides very little sl,~lospheric ozone damage. One embodiment of the invention described in U.S. Patent No. 5,151,207 comprises a ternary mixture of refrigerants that is a "drop-in" substitute for dichlorodifluoromethane (R-12), co""~"ising about 2 to 20 weight percent isobutane (R-600a), about 21 to 51 weight percent chlorodifluoroethane (R-142b), and about 41 to 71 weight percent chlorodifluo~o~ ll,ane (R-22), with the weight percentages of the components being weight percentages of the overall mixture. One embodiment of the present invention improves on the invention of U.S. Patent No. 5,151,207, by adding to the preferred embodiments disclosed therein one or more components from Tables 1 or 2.
Among tne most preferred embodiments of the present invention are mixtures of refrigerants which are "drop-in" substitutes for dichlorodifluoromethane tR-12), comprising about 0.5 to 8 weight percent isobutane (R-600a), about 15 to 60 weight percent of component B, and about 21 to 71 weight percent chlorodi~1uo,ol"el1,ane (R-22), with the weight percentages of the components being weight percentages of the overall mixture. Component B is about 1 to 99 weight percent chlorodifluoroethane (R-142b) and about 1 to 99 weight perc:ent component C, with the weight percentages of the subcomponents of component B being weight percentages of component B. Component C is about 0 to 100 weight percent heptafluoropropane (R-227ea) and about 0 to 100 weight percent o chlo,uteL,~n-loroethane (R-124), with the weight percentages of the subcomponents of component C being the weight percentages of component C.

Another embodiment of the present invention is the creation of additional "drop-in" substitutes for R-12 from novel mixtures of components from Tables 1 - 3.
Another embodiment of the present invention is the creation of a "drop-in" or near "drop-in" substitute for R-500 from novel mixtures of components from Tables 1 - 3.

It is also an object of the present invention to provide a "drop-in"
20 refrigerant substitute for R-12 that provides an accep~able level of cooling in low, medium, and high temperature applications where R-12 is now in use, and that mixes well enough with compressor oils that are miscible with R-12 to provide adequate lubrication of existing compressors that utilize R-12. The mixing with existing R-12 oils must be sufficient to allow said oils to properlycirculate through the refrigeration circuit and not become excessively trapped (or "logged" in the refrigeration trade) in the evaporator, condenser or other parts of the system. Excessively trapped oils in the refrigeration circuit can interfere with proper operation and efficiency of refrigeration systems, or in severe cases, cause compressor failure from lack of oil.

It is also an object of the present invention to provide additional na",mability suppression in R-12 systems at elevated temperatures.
It is also an object of the present invention to provide a "drop-in"
5llh5tjtUte refrigerant for R-12 that causes very little sl,dlospheric ozone damage.

It is also an object of the present invention to provide a "drop-in"
substitute refrigerant for R-12 that c~uses very little global warming damage.

o It is alsa an object of the present invention to provide a "drop-in" ornear "drop-in" refrigerant substitute for R-500 that provides an acceptable level of cooling in low, medium, and high temperature applicaliolls where R-500 is now in use, and that mixes well with compressor oils that are miscible with R-500 to provide adequate lubrication of existing compressors that utilize R-500. The mixing with existing R-500 oils must be sufficient to allow said oils to properly circulate through the refrigeration circuit and not be excessively trapped (or "logged" in the refrigeration trade) in the evaporator, condenser or other parts of the system. F~cessively trapped oils in the refrigeration circuit can interfere with proper operation and efFiciency of refrigeration systems, or in severe cases, cause compressor failure from lack of oil.

W O 97/11138 PCT~US96/14882 DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of the invention, refe;-ence will now be made to the embodiments described below and specific language will be used to describe the same. It will neverless be 5 understood that no lilr,il~lion of the scope of the invention is thereby intended, such alterations and further modi.,cdlions in the described embodiments, and such further applications of the principles of the invention as described therein being conl~i ",,~lated as would normally occur to one skilled in the art to which this invention relates.

Since the ~lanuary 7, 1991, filing date of the application which became U.S. Patent No. 5,151,207, several new refrigerant fluids which are listed in Table 1, below, have become available in commercial quanlilies. Refrigerant fluids that were referenced in U.S. Patent No. 5,151,207 are included in Table 2 for co,l"l~leteness. Additional known refrigerant fluids that are useful as 5 mixture components in the present invention are also included in Table 3.
Boiling points (BP), and critical temperatures (Crit) in Tables 1-3 are in degrees Fahrenheit and are taken from the November 1993 "NIST Database 23: NIST REFPROP v4.0", available from U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology (NIST), Standard Reference Data Program, Gaithersburg MD 20899, and the "June 1995 ARTI Refrigerant Database", available from Engineering Consultant, 10887 Woodleaf Lane, Great Falls VA 22066-3003. Molecular weights (MW) are taken from the same sources.

W O 97/11138 PCT~US96/14882 T~hle 1 R-num Formula Name BP Crit MW
R-227ea CF3CHFCF3 1,1,1,2,3,3,3- 2.5 215.37 170.0 heptafluoropropane*
R-124 CHCIFCF3 2-chloro-1,1,1,2- 8.26 252.45 136.4 tetrafluoroethane R-134a CF3-CH2F 1,1,1,2-tetrafluoroethane -1 .07 21~.07 ' 02.0 R-1~_a CF3-CH3 1,1,1-trifluoroethane - '.23 3.58 4.04 R-12 C2HF5 per,ldnlJoroethane - .43' ~'.12 20.0 0 R-E 25 CFH2-O- difluorc""~ll,yltrifluoromethyl ~'.9 176.7 36.0 CF3 ether R-E143a CH3-O-CF3 methyltrifluoromethylether -10.8 220.8 220.8 R- CHF2-CF2- 1 -(trifluoromethoxy)-1,1,2,2- 26.3 186.0 238.3 E227ca2 O-CF3 tetrafluoroethane R-245cb CH3-CF2- 1,1,1,2,2-pentafluoropropane 0.3 224.5 134.0 *At the present time, only the 1,1,1,2,3,3,3-heptfluoropropane isomer is available in commercial quantities, however, all isomers of heptafluoropropane are within the scope of the present invention.

T~hle ~
R-number FormLla Name BP Crit MW
R-600a C(CH' )3 isobutane 10.83 274.46 58.12 R-142b CF2C -CH3 1 -chloro-1,1 - 15.55 278.87 100.4 difluoroethane R-22 CHF2CI chlorodifluor~,",eLl,al1e ~1.55 207.07 86.47 Tabie 3 R-num Formula Name BP Crit MW
R-290 C3H8 propane 43.75 206.06 44.10 R-E170 CH3-O-CH3 dimethyl ether (DME) -12.7 263.8 46.07 R-1270 CH3CH=CH2 propylene -53.8 198.4 42.07 R-1216 CF2=CFCF3 hexafluoropropene -20.2 unknown 150.0 R-218 C3F8 perfluon~propane -34.1~ 161.4 188.0 R-C318 C4F8 octafluorocyclobutane 19.42 239.6 200.4 R-C270 C3H6 cyclopropane -27.2 256.3 42.1 The refrigerant fluids in Tables 1,2 and 3, may be grouped into four categories, GROUP-A, GROUP-B, GROUP-C, and GROUP-D as set forth in Table 4.. GROUP-A contains refrigerant fluids with the higher boiling points, GROUP-B contains refrigerant fluids wihich improve oil miscibility with R-12 mineral oils. GROUP-C contains refrigerant fluids with the lowest boiling points. GROUP-D refrigerant fluids may be used to dilute the other three groups. Some refrigerant fluids (e.g. R-142b) may be in more than one GROUP. Flammability is listed as "venl" for very flammable refrigerant fluids, "weak" for weakly or mildly nar"mable refrigerant fluids and "none" for nonflammable refrigerant fluids. Miscibility of the refrigerant fluid with mineral oils used in R-12 refrigeration systems at a temperature range of about -20 degrees Fahrenheit to about 0 degrees Fahrenheit is listed as "none" for no oil miscibility, as "poor" for very limited oil miscibility, as "medi" for mediocre oil miscibility, and as "good" for complete oil miscibility. Oil miscibilty with a given refrigerant fluid will improve with increasing temperature if the miscibility iS listed as "poor" or "medi". The term ''unkn" means "unknown".

W O 97/11138 PCT~US96/14882 Table 4 GROUP-A GROUP-B GROUP-C GROUP-D
R~ Fl~m ~il R~fn~ Fl~ ~il QP ~ Fl~m ~il RP~ Fl~m ~il R_~77P~ n~nP n~nP R-1~h !~k mP~i R-~ nnn~ r~r R_1~ nnnP nnn~
R-1~4 nnn~ r~nr R~nn~ v~ ~nn~ R-1~ nnn~ nnn~ R_1~1~ nnn~ nnn~
R_14~h w~k m~i R-~n v~ ~nn~ R-14~ wP~k nnn~
R_F14~ llnkn ~nn~ R_F14~llnk a~n~ R-F1~ nnnP llnkn R-F7~7~ nnn~ llnkn R-F17n vP~ ~n~ R-~1~ nnn~ nnnP
R_~ h llnkn ~Inkn R-1~7n v~ o~n~
R-~1R n~n~ nnnP R_~77n v~ ~nn~

Preferred embodiments of the present invention include a mixture of refrigerant fluids with one or more components from GROUP-A, zero or more components from GROUP-B, one or more co""~ol,ents from GROUP-C, and zero or more components from GROUP-D, s~ ~hject to the three following Col~iLiûl~s.

Condition 1. The resulting temperature versus pressure curve of a closed collldi,,er conlaining said mixture of refrigerant fluids, such that all component refrigerant fluids coexist in both liquid and vapor states in the container, should approximate the temperature-pressure curve of a closed container of R-12 for the range of temperatures and pressures cGr"",only used for R-12 refrigerant, about 40 degrees Fahrenheit to about 200 degrees Fahrenheit.
The degree of app~uXilndlion should be within about 15 percent to about 30 percent error. To account for the "glide" in the mixtures of refrigerant fluids, CA 02232674 l998-03-20 the "bubble point" pressure at a temperature of 70 degrees Fahrenheit should be around 10 percent higher than the pressure (gauge pressure, PSIG) of R-12. Increasing the mass fraction of components from GROUP-C
and decreasing the mass fraction of components from GROUP-A will cause 5 the pressure versus temperature curv~ of the mixture of refrigerant fluids to increase and vice versa. Rarely, two or more refrigerant fluids may be combined and the resultant boiling/bubble point of the mixture may not lie in between the boiling points of the components. This is the result of a partial orcomplete a,eol,ùpe formation. If an a;zeotrope is formed, the resultant 0 boiling/bubble point is often near or a few degrees lower than the component with the lowest boiling point. If an unwanted azeotrope forms, additional components can be added to further modify the temperature-pressure curve.
If the object is to produce a "high performance" or "higher capacity"
mixture of refrigerant fluids, which may only be usable under certain CGndiliOlls, such as auLu",~ /e air conditioning, where extra horsepower is available for cGl"pr~ssor operation, or in low temperature situations where the compressor is under loaded, then the mass fraction of the components from GROUP-C may be further increased about 5 to about 20 weight percent.
Conversely, to produce a "reduced capacil~/" mixture of refrigerant fluids, the mass fraction of GROUP-C components may be reduced by about 5 to about 15 weight percent. Reduced capacity refrigerant mixtures will often perform poorly (but still useable) in "normal" systems. Air conditioning systems which were oversized when installed, may use a reduced capacity refrigerant to obtain a better equipment load match to the heat load. Properly sized air conditioning systems provide far better humidity control (longer run times) than do oversized systems.

Condition 2. The resulting miscibility of mineral oils used in R-12 refrigeration systems with the mixture of refrigerant fluids created shall be great enough to provide for adequate circulation of said oils throughout the refrigeration circuit WO 97tlll38 PCT~US96/14882 without undue trapping or "logging" of said oils in any part of the system as tonot interfere with the proper operation of the refrigeration system in the rangeof desired temperatures. Increasing the mass fraction of components from GROUP-B in the mixture of refrigerant fluids will increase miscibility with R-12 compressor oils at a given temperature and vice-versa.
In general about 4 to 5 weight percent (of the total rer,igerdnt mixture) of highly flammable GROUP-B components seem to provide usable mineral oil return in most cases, especially when combined with other weakly llar,ll"able GROUP-B components. Highly nar"",able GROUP-B components l0 can usually be increased to about 8 to about 10 weight percent if weak na"""ability can be tolerated. Lowering the highly namr"able GROUP-B
components to as low as about 1 weight percent of the total refrigerant mixture will compromise mineral oil miscibility but will often result in a refrigerant which is useful under some conditions such as high temperature air conditioning or household refrigerators which can tolerate poor oil return.
Condition 3. The resulting mixture of refrigerant fluids should be nonflammable or weakly flam",able at worst. The n,dki"~.lm mass fraction of "very" na"""dble refrigerant fluid components will be limited to about 5 to about 10 percent. The maximum mass fraction of "weakly" nan,n,able refrigerant fluid components will be limited to about 15 to about 60 percent. A
test sample of the mixture of refrigerant fluids should be vapor leaked (fractionated) at several constant temperatures over the range of expected temperatures ~here the leaking may occur. Some temperatures for fractionation testing would typically be -20 0 40 70 120, 180 degrees Fahrenheit. Fla~ ability tests should be conducted on the mass fractions of vapor and liquid phases and be analyzed with appropriate equipment (e.g. a gas chromatograph) at various points during each leak down to verify the mass fraction of flammable components does not become great enough to cause greater than "no" or "weak" flammability as desired. Flammability can W O 97/11138 PCT~US96/14882 also be reduced by placing the boiling point of a very or weakly nalni "able refrigerant fluid near a lesser flammable or nonflammable refrigerant fluid component with a similar boiling point. Total ilalnr~,ability may also be reduced by spreading out (by boiling point) the flammable components over the entire blend instead of using just one llal"r"able component.

For the purposes of making the mixture of refrigerants of the preferred embodiments of the present invention, one needs to procure the following equipment, or equivalents. A mixing cylinder, which can be a standard refrigeration industry "recovery" cylinder or a small propane (20 pounds net 0 weight propane) tank is needed. These are U.S. Department of Transportation (DOT) rated at 240 PSI(~ or higher. This tank (or cylinder) must be clean. Also needed is a refrigeration (or equivalent) vacuum pump, scales, and a refrigeration manifold set (hoses and gauges).

The air must be removed from the mixing cylinder with a vacuum pump, such as any used by refrigeration service technicians. A deep vacuum gauge is needed to verify that about a ~00 micron vacuum is achieved on the mixing cylinder. Deep vacuum gauges which read to less than 25 microns are commonly available at refrigeration supply houses.

This mixing cylinder is piaced on electronic charging scales, of the type 20 commonly available to the refrigeration service technician. These scales often read in 1/2 ounce increments up to a total of 60 pounds or more total weight.

A refrigerant mixture is made, by connecting up each component supply cylinder to the mixing cylinder on scales, and weighing in the appropriate weight percentage of each component. The mixing hoses or manifolds should be purged or ev~cu~ted first to remove air and moisture.
Each component supply cylinder should have a "dip tube" or eductor tube to withdraw the component in liquid phase. If the supply component cylinder WO 97/11138 PCT~US96/14882 -2~-does not have a dip tube, it must be inverted to obtain the component in liquid phase.
Although, the components can be mixed in any order, it is easier to add the high boiling components first. The vacuum on the cylinder will usually be sufficient to draw in the required amount of the first component.

Some sort of liquid pump will be required to transfer the ,t:i"ai"i"g GROUP-A and GROUP-B components as the pressure on the mixing cylinder will rise to match the supply cylinder.

Instead of a liquid pump, the mixing cylinder may be chilled by any convenient means by 10-20 degrees Fahrenheit colder than the supply cylinders. Alternately, the component supply cylinder may be heated 10-20 degrees Fahrenheit warmer than the mixing cylinder to facilitate the transfer.
A hot water bath or cylinder heating blanket works nicely for this purpose.

When transferring GROUP-C components, no pump will be needed, as the higher pressures of GROUP-C components will (rapidly) transfer them to the mixing cylinder. Caution is advised, for after the relatively slow transfers for GROUP-A and GROUP-B components into the mixing cylinder, GROUP-C
components will transfer very quickly, possibly surprising the person doing the mixing, and causing too much of a component to be transferred.
A refrigerant mixture, just completed, should be allowed to thermally stabilize or 12 hours or more before temperature and pressure measurements are taken, if needed. If static pressure and temperature measurements are not needed, a mixture may be charged into a refrigeration or air conditioning system and operated, without the 12 hour or more delay. A refrigerant mixture should always be unloaded from the mixing cylinder in liquid phase when charging into an appliance or other refrigeration system. This prevents fractionation from changing the composition of the mixture during charging.
-The mixing cylinder may contain a "dip tube" to provide for unloading in liquid phase. If a mixing cylinder is used without a dip tube, the cylinder must be inverted to unload in liquid phase.
If a mixture contains significant mass fractions of components with high 5 molecular mass, the mcls~,ul~r mass of the total refrigerant mixture will increase. This may be beneficial for operation in centrifugal chiller refrigeration systems.

Extensive use of R406A, described by U.S. Patent No. 5,151,207, shows the mixture of refrigerants to be zeotropic, which means the 10 composition changes during evaporation and condensalion phases of refrigeration or air conditioning system operation. Unlike a single component refrigerant, such as R-12, zeotropic rerligeranLs do not evaporate or condense at a single temperature (for a given pressure), but they evaporate or condense over a small range or "glide" of temperatures. Depending on the 15 temperature, the glides involved for both R-406A and the preferred embodiments of the present invention are in the order of 10 to 15 degrees Fahrenheit.
Some rer, igerdlion systems have seen performance improvements upwards of about 30 to about 40 percent due to the glide factor. Other systems exhibit similar performance to that of R-12. Events taking place in the condenser are broken down into 3 rough areas. The hot gas upon entering the condenser is first desuperheated, no condensation takes place in this area, just a relatively low amount of heat is rejected in cooling the hot gas down to the point where it is ready to condense. The second area involves 5 the actual condensation of the gas, where a phase change occurs to liquid state. A relatively high amount of heat is given off due to the phase change.
Thirdly, the now liquid refrigerant is further cooled (called subcooling in the art), with a relatively low amount of heat rejected.

Zeotropic mixtures, such as those of the present invention, cause the condensation phase change area (and evaporation phase change area) to occupy more of the condenser (or evaporator), thus increasing the capacity of the condenser to reject or the evaporator to gain heat.

Oil miscibility may be tested by mixing refrigerant and oil samples in a glass tube refrigerant charging cylinder, such as a "Dial-a-Charge" or a smaller device called a "Vizi-vapor" charging device that can hold 2 or 3 fluid ounces of refrigerant/oil mixtures. The sample is chilled to the desired temperature of operation and then observed for the oil separating from the o refrigerant. Complete or almost complete separation is a sign that the oil and refrigerant may be immiscible at the sample temperature and oil return problems to the compressor might be expected. If the oil and refrigerant stay mixed or only separate only a small amount, then oil miscibility at the tested temperature is assured. If a large amount of separation is observed, further testing needs to done, preferably in a real refrigeration system or refrigeration system test stand.

Oil miscibility can also be tested in a real system, by using a system with a compressor with an oil sight glass in the crankcase. Once the desired temperatures are reached, the oil level is observed, and if it drops, then it isprobably not being returned from the evaporator, and a more miscible combination must be used. Sight glasses should also be present in critical areas of the system, where oil logging may occur (e.g, a low spot in the evaporator or the suction line) The few fluid ounces of oil needed to log an evaporator enough to interfere with system operation, may not cause an easily detectable loss of oil on the compressor crankcase sight glass due to all the foaming and churning in the crankcase from compressor operation, and hence the need to install sight glasses or other means of detecting oil logging in critical system areas.

Table 5 lists current ozone depletion potentials (ODPs) and global warming potentials (GWPs) of the components used in the following examples. ODP (ozone depletion potential) is calculated for mixtures by using June 1995 ARTI Refrigerant Database, reported ODPs of the individual component weight percentages. R-12 lhas an ODP of 1.0, the benchmark ODP. GWP (global warming potential)l is calculated relative to CO2, from the same source. Each following example will list calculated ODP (as ODP=) and GWP (as GWP=) for the mixture of that example.

Table 5 Refrigerant Fluid ODP (100 year) GWP (100 yearto C02) R-12 1.0 7900 R-22 .050 (semi-empirical) 1700 R-142b .066 (semi-empirical) 2000 R-124 .030 (mod01-derived) 480 1~ R-227ea .000 3300 R-E170 .000 0 R-600a .000 0 Example 1 (a most plreferred embodimenV

25 pounds of R-600a/142b/124/22 4116.5128.5151 (ODP=.0449 GWP=1334), a "drop-in" substitute refrigerant for an R-12 automotive air conditioning system, were blended into a mixing cylinder (30 Ib "disposable"
DOT-39 cylinder manufactured by Worthington Cylinders) with a dip tube WO 97/11138 PCTAUS96/14882.

using the methods and procedures described above. Flammability suppression was desirable and the higher evaporator temperatures in a car (32 degrees Fahrenheit and above) resulted in good oil miscibility, even with higher percentages of R-124 (lower percentages of R-142b). There was less 5 flammability suppression and more oil miscibility than in Example 2, below.
The refrigerant mixture of this Example (minus the oil) has been found to be nG,llldf "r"able, even after worst case vapor leakage (fractionation), at cold temperatures (-10F range), with worst cases (highest concentrations of narl " "ables) points tested for flammability at 100 degrees Centigrade with lo methods speclf~ed by UnderWriters Laboratories (UL) standard 2182.

Two pounds of the refrigerant mixture of Example 1 where charged into the air- conditioning system of a 1990 Pontiac Transsport minivan.
Driving 35 mph at an ambient temperature of 80 degrees Fahrenheit, discharge air duct temperatures of 36 to 39 Fahrenheit were achieved.
15 Controls were set to "MAX" (recirculate) and the highest fan speed. Low side (suction) pressure was 30 PSIG (set by the GM-V5 variable displacement compressor), high side (head) pressure was 150 PSIG. Later in the day, when the ambient temperature fell to 75 degrees Fahrenheit, the head pressure dropped to 125 PSIG, and the duct temperature rose to 39 to 42 20 degrees Fahrenheit.
The Example 1 refrigerant mixture was also charged into several taxicab vehicles in Florida for a two month test, and the company reported back good results. Additional testing at a technical school in Florida in stationary equipment, showed nearly identical results to R~06A.

The Example 1 refrigerant mixture was run in an oil miscibility test stand, a real refrigeration system, described in appendix A. Evaporator and suction line sight glasses showed the refrigeranVoil mixtures becoming cloudy in the range of -25 to -30 degrees Fahrenheit, a sign that refrigeranVoil WO 97/11138 PCT~US96/14882 miscibility is starting to be lost. The mineral oil used was Suniso 3GS 150 viscosil~, the type commonly found in stationary R-12 refrigeration equipment.
Oil return to the compressor was still acceptable after 48 hours of running at -~ 40 degrees Fahrenheit on the evaporal:or.

AulomoLi~/e compressor mineral oil, Suniso 5GS 525 viscosity, was also tested and found to go cloudy at around 15 degrees Fahrenheit. A 4 hour run showed this thicker oil still returned acceplably at around 5 degrees Fahrenheit. This is enough miscibility for automotive air conditioning systems, where evaporator temperatures are 25 degrees Fahrenheit or higher.

The Example 1 refrigerant mixture offers roughly 20 percent less ozone depletion and about 25 percent less global warrning than does R-406A. Example 1 refrigerant mixture o~fers about 96 percent less ozone depletion and about 83 percent less global warming than R-12.
R-600a/142b/124/22 4116.5128.5151 ODP=.0449 GWP=1334 (Example 1) R-600a/142b/22 4141155 ODP=.0546 GWP=1755 (R406A for comparison) R-12 (pure) 100 ODP=1.000 GWP=7900 (R-12 for comparison) F~cample ?

R-600a/142b/124/22 4113133150, a "drop-in" substitute refrigerant mixture for an R-12 automotive air conditioning system, is created in the manner set forth in Example 1 above. Flammability suppression is desirable and the higher evaporator temperatures in a car (32 degrees Fahrenheit and above) results in good oil miscibility, even with higher percentages of R-124 WO 97/11138 PCTrUS96/14882 (lower percentages of R-142b). The blend in this Example was computer simulated with NIST program REFPROP V4.0 and showed good results.

Compared to R-406A, the Example 2 refrigerant mixture offers about 20 percent lower ozone depletion and about 30 percent less global warming.

R-600a/142b/124/22 4113133/50 ODP=.043GWP=1268(Example2) R-600a/142b/22 4141/55 ODP=.0546 GWP=1755 (R406A for comparison) F~ample 3 R-600a/142b/124/22 413417l55, a "drop-in" substitute for R-12 in a walk-in freezer, operating at -20 degrees Fahrenheit, is created in the manner set forth in Example 1 above. Due to the low evaporator temperature, oil miscibility is of paramount importance. A higher percentage of R-142b and a lower percentage of R-124 are used. Computer simulations showed good results.

The Example 3 refrigerant mixture offers about same ozone depletion and global Wdl l l lil 19 as R-406A. Any weak lla, l Imability which might result from a vapor leak of R-406A under cold temperatures is reduced.
R-600a/142b/124/22 413417l55 ODP=.052 GWP=1648 (Example 3) R-600a/142b/22 4/41155 ODP=.0546 GWP=1755 (R-406A for comparison) F~ample 4 (a most preferred embodimenV

R-600al142b/227ea/22 4115/40141, a "drop-in" substitute refrigerant for an R-12 automotive air conditioning system, is created in the manner set forth in Example 1 above. A high percentage of R-227ea is used and some nar"",ability suppression is provided in the event of a collision where refrigerant lines are ruptured and compressor oil is sprayed onto hot exhaust manifolds or the catalytic converter. This mixture also has a lower ODP than ~ other Examples. This refrigerant mixture has been computer simulated using 5 NIST REFPROP V4.0 and showed favorable results.
Example 4 offers almost one half the ozone depletion of R~06A (97 percent less ODP than R-12), however, the global warming potential is about 25 percent greater than R-406A.

R-600a/142b/227ea/22 4115140/41 ODP=.03 GWP=2317 (Example 4) R-600a/142b/22 4141155 ODP=.0546 GWP=1755 (R406A for comparison) Two cylinders, each cGnlai"ing 25 pounds of the Example 4 refrigerant mixture, were made in the manner set ~orth above. About two pounds of the Example 4 refngerant mixture were charged into the oil miscibility test stand described in Appendix A. Oil return to f;he compressor was slightly worse than for the refrigerant mixture of Example 1. Oil return was still adequate down into the -20 to -30 degree Fahrenheit range. Suniso 3GS (150 viscosity) mineral oil was used.

2.5 pounds of the Example 4 refrigerant mixture were charged into a Nor-Lake brand 4 door chest type cooler made for R-12 refrigerant. This unit is at least 30 years old and had been out of service (leaks and dirty condenser coil) for two years (R-12). The unit was first cleaned up and repaired and charged with R-406A rer, i~ardnt mixture to verify operation.
The R-406A refrigerant mixture was removed before charging in the Example 25 4 refrigerant mixture. The cooler ran normally. Ambienttemperaturewas about 78 degrees Fahrenheit. and upon initial startup, the head pressure was 148 PSIG. and the suction pressure was 40 PSIG. After sixteen minutes~ the W O 97111138 PCT~US96/14882 unit had cooled down and cycled off, with the head pressure being 128 PSIG
and the suction pressure being 21 PSIG at the end of the cycle.

Fxample 5 R-600a/142b/1 241227eal22 4/15/17/20144, a "drop-in" substitute refrigerant for an R-12 automotive air conditioning system of the following mixture is created in the manner set forth in Example 1 above. More nonflammables are delivered at higher boiling points than Example 4 in the case of a system rupture. This mixture has been computer simulated using NIST REFPROP V4.0 with good results.
Example 5 is a compromise between Examples 1 and 4. Ozone depletion is reduced about one third R-406A with similar global warming to R-406A.

R-600a/142b/1241227ea/22 4/15/17120144 ODP=.037 GWP=1789 (Example 8) R-600a/142b/22 4141155 ODP=.0546 GWP=1755 (R-406A for comparison) FY~rnple 6 R-E170/142b/124/22 4116.5128.5151 (ODP=.0449 GWP=1334), a "drop-in" s~ stitute for R-12, was created in the manner set forth in Example 1, above. It is the same as Example 1, except that Dimethyl ether (R-E170) has been substituted for the isobutane (R-600a), which created an equivalent refrigerant. R-E170 has good mineral oil miscibility, as does isobutane. The temperature-pressure curve almost exactly matches that of Example 1 (See Figure 1).

A cylinder containing 25 pounds of the Example 6 refrigerant mixture was made in the manner set forth above. About 8 ounces (weight) of Example 6 refrigerant mixture were charged into a Kelvinator model FDK190KNH2 household refrigerator. The refrigerator was started at room temperature (about 70 degrees Fahrenheit). After 30 minutes of operation, pressures, and the compressor Ampere draw were normal. Suction pressure 5 was 2 PSIG, head pressure was 125 PSIG, and the compressor current draw was 2.2 Amperes (current draw with R- l 2 was also 2.2 Amperes). Inside freezer compartment was 20 degrees Fahrenheit and the fresh food compartment was at 36 degrees Fahrenheit. However, the service technician noted that the condenser inlet was hotter to the touch than it would have been lO with R-12. This is due to the higher heat of compression of the R-22 component. R-406A exhibits slightly higher compressor discharge temperatures than R-12 also. The slighltly higher discharge temperatures are well within equipment operating capabilities and cause no problems. The "frost line" was at the end of the evaporator.

FY~ple 7 4 pounds of the Exa",ple 6 refrigerant mixture were charged into the R-12 air conJiLioni"g system on a 1985 MACK "cab-over" semi tractor. The system performed identical to factory specifications for this system charged with R-12. Design suction pressure range was 18 to 25 PSIG (at 2000 RPM, 80 degrees Fahrenheit ambient), the system with the Example 6 refrigerant mixture ran at about 19 to 20 PSIG on the suction side. Design head pressure range (with R-12) is 250-275 PSIG with 260 PSIG being measured when operating on the Example 9 refrigerant mixture.

F~am~le 8 A "Masterbuilt" brand chest type cooler was also charged with 9.0 ounces (weight) of the Example 6 refrigerant mixture. lt used a thermostatic expansion valve (TEV) refrigerant metering device. After 15 minutes of operation, the suction pressure was 40 PSIG and the head pressure was 130 WO 97/11138 PCT~US96/14882 PSIG, with the food compartment temperature being 35 degrees Fahrenheit.
Compressor current draw with the Example 6 refrigerant mixture was 1.8 Amperes (1.9 Amperes for R-12). The refrigerant sight glass was clear (no bubbles). The "frost line" was at the end of the evaporator.

FY~n ple 9 A Frige-Air brand display case model LKC2680 (TXV refrigerant metering device) was charged with 6 ounces (weight) of the Example 6 refrigerant mixture. The "pull down" (cool down until unit cycled off) for this unit was 18 minutes for both R-12 and the Example 6 refrigerant mixture.
lO The food compartment temperature at the end of the cool down time was 34 degrees Fahrenheit for the Example 9 refrigerant mixture and 40 degrees Fahrenheit for R-12. The refrigerant sight glass was clear (no bubbles) and the "frost line" was at the end of the evaporator. Compressor current draw as 1.9 Amperes for both the Example 6 refrigerant mixture and R-12. A higher condenser inlet temperature (compressor discharge) was also observed by feel.

Additional refrigerant miYtures Additional refrigerant mixtures are created in the manner set forth above from components in Tables 1-3 using Conditions 1-3. Some of the mixtures may not be the best performers nor have the best mineral oil miscibility, but they should be functional in at least some types of R-12 refrigeration or airconditioning systems as a "drop-in" replacement for R-12.

FY~mple 10 R-600a/124/1 34al22 6126/40128 Poor oil miscibility, may only work for high temperature systems, such as cars. Dilution by R-134a also reduces the glide (and performance).

F~ample 11 R-227ea/22 75/25 Very poor oil miscibility, might work in some cars. Would work if oil was changed to alkylbenzene.

F~mple 17 R-124/142b/125 47/15138 Poor oil miscibility, low critical temperalure, may work in high temperature systems (cars). Temperature-pressure curve is OK. Low critical temperature may generate high head pressures ancl loss of performance in hot cl;",ates or 10 stopped traffic.
FY~mple 13 R-600a/142b/124/22 1.5/9.5/39150 Very good flammability suppression at elevated temperatures, but very poor miscibility in mineral oil. This will only be useful in high temperature air conditioning systems, such as some cars, and household refrigerators which can tolerate almost zero mineral oil refrigerant miscibility. Certain cars, withcompressors mounted higher than the evaporator and using a small oil charge may see oil starvation due to poor oil return.
F~mple 14 R-600a/142b/124/218 418113175 Low critical temperature, but will still perform better than R-134a. Good oil miscibility. The U.S. EPA currently takes a dim view of perfluorinated fluorocarbons ~R-218) since they are so stable and do not easily break down in the atmosphere for thousands of years, adding to global warming. This thinking might change in the future as rnore is learned about the global warming mechanisms.

W O 97/11138 PCT~US96/14882 F~mple 15 R-600a/124/134al22 6126140128 Improvement to FRIGCTM FR-12TM, increase oil miscibility, and capacity. This mixture may work about the same as R-12 but not as good as a mixture with a higher glide, such as R~06A or a preferred embodiment of the present invention. This embodiment will have better oil miscibility than does FR-12TM, but it is still very limited, and useful only for high temperature systems.

Fxam~les 16-113 Additional refrigerant mixtures of the present invention of Examples 16-113 are summarized in Table 6, below. For completeness, Examples 1 -15 are also included in Table 6. Most of the refrigerant mixtures in Table 6 were computer simulated with NIST plO9~drll REFPROP V4.0 and showed good results. General coml"elll(s) are included for each entry in Table 6. The "fig." column refers to the figure number containing the temperature-pressure chart for the blend. The word "oil" in Table 6 is meant to mean "mineral oil used in R-12 refrigeration and air conditioning systems". Oil miscibility (ability of the oil to correctly return to the compressor is given a letter "grade" of A to F defined as follows:

A No problems with mineral oil return (150 viscosity) down to -50 degrees Fahrenheit or colder evaporator temperatures.
B No problems with mineral oil (150 viscosity) return down to about -30 degrees Fahrenheit evaporator temperatures.

C No problems with mineral oil (150 viscosity) return for most R-12 systems down to about -10 to about 10 degrees Fahrenheit. A small WO 97/11138 PCT~US96/14882 number of systems may log oil or fail from poor oil return even at about 10 degrees Fahrenheit evaporator temperatures.

D Only usable in some systems, and only for "high temperature" (air conditioning, about 35 degrees Fahrenheit and warmer) use. Due to small line sizes (high suction gas velocities), many R-12 household refrigerators would still be usablle, but not R-12 "conlmercial refrigeration" systems.

F Total m;neral oil i~"n,iscibility with the refrigerant. Only a very few systems, probably "household" refrigerators, would be able to operate correctly. Pure R-1 34a (in mineral oil) is a good example of "F". It is outside the scope of the present invention to claim a refrigerant mixture with no miscibility in mineral oil, therefore, no examples are included with a mineral oil miscibility of "F" in Table 6, below.

I able 6 o -Example components Composition oil fig. Generalcomments x R-600a/142b/124/22 4116.5/28.5151 A- 1 preferred embodiment, best overall refrigerant 2 R-600a/142b/124/22 4113133150 B+ 2 slightly loweroil miscibility, betterfla~ ability suppression 3 R-600a/142b/124/22 413417155 A 2 might fractionate to slightly flammable (vapor leaking) 4 R-600a/142b/227ea/22 4/15/40/41 B 2 preferred embodiment, more costly, less oil misc than Example 1 ~, R-600a/142b/124/227ea/22 4115117120/44 B 2 combination of Example 1 and Example 4 D
6 R-E170/142b/124/22 4116.5128.5151 A- Equivalent to Example 1 except using R-E170 instead of R-600a 7 thru 9 same refrigerant as Example r R-600a/124/134a/22 6126140128 C- 2 reduced glide (dilution by 134a) com,~)ar~:d to Example 1 ~ ~
11 R-227ea/22 75/25 D- 3 verybadoilmisc, excellentfiresu,upr~ssion O
12 R-124/142b/125 47/15/38 D 3 poor oil misc. glide too high 13 R-600a/142b/124/22 1.519.5139150 D+ 3 good flammability suppression, but poor oil miscibility o 14 R-600a/142b/124/218 4/8/13175 C- 3 R-218 is PFC, currently banned by USEPA for refrigerants R-600a/124/134a/22 6126140128 C- 3 pooroi return,toD+aftervaporleaking 16 R-600a/124/134a/143a 6140126128 D+ 4 pooroi return 17 R-600a/124/134a/143a/125 6/40/26/14/14 D+ 4 pooroi return 18 R- 6/40116114114/10 A weakly flammable, oil misc to D+ after vapor leaking 600a/124/134a/143a/125/121 19 R-600a/124/134a/143a/290 314412612413 D 4 poor oil return R-600a/124/134al290/22 314012613128 D+ 4 poor oil return x Table 6 Cont.
o Example Components Composition Oil fig. Generalcomments ~~
21 R-142bl12411 34al290122 1511512614140 B+ 5 oil misc will degrade to C- or D+ after vapor leaking 22 R-E143a/E17011241142bl22 515128112150 B+ limited availability of R-E143a 23 R-227eal142bl22 40120140 D 5 expensive (227ea), poor oil misc 24 R-600a/142b/124/22 4/14.5120.5161 B+ 5 "high per~ormanceN version of Example 1 (higher pressures) R-2901142bl22 5146149 A 5 weakly flammable, oil misc to C after vapor leaking 26 R-2901142bl22/600a 214415113 A 5 weakly flammable after vapor leaking D
27 R-600al142b/124/22/290 411613214414 A 6 good refrigerantl slight decrease in oil misc upon vapor ~
leak to B+
28 R-600a/142bt124/22/1270 411613314314 A sood re~lgsrâ~lt, slisht dec~ase in oil mis.. upor, vapor ~, leak to B+ r 29 R-600al142bl1241E1251290 411613314314 A good refrigerant, slight decrease in oil misc upon vapor leak to B+
R-600a/142bl1241E12511270 411613214414 A good refrigerantl slight decrease in oil misc upon vapor leak to B+
31 R-600a/142b/125/290 41491~31~ A 6 wea<lyflammabeaftervaporleakinglhighglide 32 R-600al ~2~/125/1270 41501~21~ A wea~lyfla~ abea tervaporleaking, highglide 33 R-600a/ ~2~12211251290 41~512412314 A 6 wea~Iyflammabea tervaporleaking, slightlyhigherglide 34 R-600a/~ ~2 ~/22/125/1270 41~612412214 A 6 weakly flanll "ab e a ter vapor leaking, slightly higher glide R-600al ~2 ~l 3~al221290 41~ 51' 01~615 A 6 oi m sc slight decrease to B+ on vapor leak, reduced glide 36 R-600a/ ~2bl 3~al2211270 41361 01~515 A oi mscslightdecreasetoB+onvaporleak, reducedglide 37 R-600al 241221230 ~1521~01~ B- 7 oi mscdecreasetoC-onvaporleaking 38 R-600al 2412211270 ~1531'91~ B- oi mscdecreasetoC-onvaporleaking 39 R-600a/ 24/134al22 ~1371201~9 D+ 7 lowglide, lowoilmisc.
x Table 6 Cont.
o x Example components Composition oil fig. Generalcomments R-600al227ea/22/290 416512714 B- 7 expensive (227ea), oil misc degrades to D+ after vapor leaking 41 R-600a/245cb/22/290 416312914 B- 7 expensive (245cb), oil misc degrades to D+ affer vapor leaking ~2 R-600al227eal221290/134a 41551 714120 C+ 7 expensive(227ea) ~3 R-E170/600a/142b/22 21214 155 A weaklyflalr,m~tx'o aftervaporleaking D
~4 R-600a/E170/142b/124/22 212117129150 A- equivalent to Example one, some R-600a replaced with ~~~

R-E170/142b/22/290 414115114 A+ might be weakly flammable, oil misc goes to A- vapor leaking ~
46 R-E170/142b/124/22/290 411712914614 A oil misc goes to A- after vapor leaking r 47 R-E170/227ea/22 4171/25 D expensive (227ea), poor oil misc 48 R-E170/227ea/125/143a/290 415412011814 C+ expensive (227ea), oil misc drops to C- after vapor leaking, 0 ODP O
49 R-E170/227ea/134a/125/290 415212012014 C+ expensive (227ea), oil misc drops to C- after vapor leaking, 0 ODP
R-600a/227ea/134a/143a/290 415412011814 C+ 8 expensive(227ea),oilmiscdropstoC-aftervapor leaking, 0 ODP
51 R-600al227eal134a/125/290 415212012014 C+ 8 expensive (227ea), oil misc drops to C- after vapor leaking, 0 ODP

~x I al)le ~ ~;ont.

-Example components Composition Oil fig.Generalcomments 52 R-E227ca21600a/218/290 271416514 C- oil goes to D- aftervapor leaking, R-218 not EPA
approved 53 R-C318/E170/218/290 281416414 C- oilgoestoD-aftervaporleaking,R-C318,218notEPA
approved 54 R-E227ca2/600a/218/1270 291416314 C- oil goes to D- after vapor leaking, R-218 not EPA
approved R-600a/ ~2b/E125 4141155 A weaclyfla"""ableafervaporleaking D
56 R-600a/~2b/E125/290 214115512 A weaclynalllllP~'e,olmisctoB~aftervaporleaking O
57 R-600a/ ~2b/~25 4146150 A 8 weaclyfla"~lnablea ervaporleaking, highglide 5~ R-BQ0a/142b! 24/125 4! 8132146 ~ 8 similart~Example 1,bllthigherglide 59 R-600a/142b/ 24/125/290 41~813214214 A 9 oil goestoA-aftervaporleaking ~ r ~-600a/227ea/125 41 9127 D 9 expensive '227ea), pooroilmisc,goodglide,zeroODP
61 ~-E170/227ea/125 4169127 D expensive~227ea),poo oilmisc,goodglide,zeroODP
62 ~-600al1241134al1251290 314212612613 C- 9 oilmiscwil droptoDa~ervaporleaking ~
63 ~-600al142b/227eal22 4/15130151 B 9 "high performance" vers on of Example 4 (higher pressures) 64 R-E170/142b/124/22 4114.5120.5161 B~ "high performance" version of Example 8 (higher pressures) R-600a/142b/124/22/290 411612215414 A 9 Uhigh performance" version of Example 30 (higher pressures) v X
._ O O~,, ' E ~ ~, ~, C = ~ s G C

s s .-s~ a~ ~~ s ss O ~--- ~ G -- G G G E~ u G ~ G
O~c -- O c O O ~ a)~-- ~~ Q ol Q
Q~ S Q c~ Q Q s 2-- _ ~ Q ~5 o~ ~ ' ~ ~ $
m~ ~" m ~c m m ~s O~
O~ O O O ~ ~ Q 8 8 8 oF ~ ~ 2 ~ g a~ a~g g ~ ~ C~ c ~

c s a~ F s E c ,. u~ Q-- Q Q ~ ~ ~ ~d 't _ ~ o ~) .-- ~ .a) Q ._ ._ x ~ x s x x a) a~ o ~) a) O S ~2 Q o C~:7 s ~; o o a) a~ 3 3 3 3: Q
ooooo ~ . ~ .C~lC~J

+ , ~ + + , + + + + + + + +
m m m m m m m m m m m m m m ~

~ u~ o 8 oo ~ ~n CO ~ ~ ~ ~~ ~ ~ ~ CO ~ ~ ~~ ~ ~ t~7 U~
C~
U~ ~ ~ o O
C~l O O ~ ~

Sy _ ~ D ~ ~ ~ ~ -- ~~ D ~! -- '3 _ a ~ -- ~ ~ -- -- ~ ~ t~ ' ~ CIS '~ ~ ~ D
O C oO o o ~ I' 1~ ' G O O ~, ~1 ~ N

rable 6 Cont.
o -Example components Composition oil fig. Generalcomments 84 R-142b/125/290 5214315 A 12 weakly rlal"",ablE, oil goes to C-/D+ affervapor leaking, high glide R-142b/ 43a 57/43 D+ 2 weaklyn~"l",able, highglide 86 R-600a/ 2411251290 614414614 B+ 2 highpelru,~"anceversionofExample70 87 R-124/1~-3a 68/32 D- 3 very marginal mineral oil misc.
88 R-E170/227ea/ 43a 5170125 C- zeroODP
89 R-600a/227ea/ 43a 5170125 C- 13 zeroODP
R-600a/124/12 /1270 615513514 B+ oilmiscdropstoB-onvaporleaking,higherglidethanEx.

9i i~-E170/124/22/127û 6/49/4114 B+ oii misc drops to B- on vapor leaking r 92 R-E170/124/125/127û 615513514 B+ oil misc drops to B- on vapor leaking 93 R-600a/227ea/125/1270 517 1201~ B+ expensive(227ea), lowcriticaltemp, highglide, zeroODP
94 R-E'701227eal1251127û sn 12ûl~ B+ expensive(227ea), lowcriticaltemp, highglide, zeroODP O
R-E 70/142b/125/1270 415CI421~ A weakly nall",lable 96 R-1~2b/125/1270/134a 47138151 û A weaklyflammable,oilmiscdropstoC-/D~onvapor ~
leaking 97 R-142b/125/127û 5314215 A weakly flammable, oil goes to C-/D+ affer vapor leaking, hig l glide 98 R-60ûa/142b/124/22 8114.5126.5151 A~ 13 Ex with more isobutane, weakly nd"~l"al)le, still usable 99 R-6ûûal142bl124122 2117.5129.5151 C 13 Ex with less R-600a, worse oil miscibility, usable in some systems Table 6 Cont.

Example components Con~position oil fig. Generalxmments 100 R-600a/142b/124/22 4121.5123.5141 B 13 Ex1 with less R-22, lower pressures, usable in some systems 101 R-600a/142b/124122 419121166 C~ 14 Ex1 with more R-22, higher pressures, usable in some systems 102 R-600a/142b/227ea/22 8113138141 A- 14 Ex4withmoreisobutane,weaklylla"""dble,stillusable 103 R-600al142bl227ea/22 2116141141 C- 14 Ex4 with less R-600a, worse oil miscibility, usable in some ~, systems D
104 R-600a/142b/227ea/22 4120145131 A- 14 Ex4 with less R-22, lower pressures, usable in some ~~
systems 105 R-600a/142bl227ea/22 418132156 C+ 14 Ex4 with more R-22, higher pressures, usable in some systems p 106 R-E170/142b/124122 8114.5126.5151 A+ Ex6 with more DME, weakly nal""~able, still usable '~
107 R-E1701142b/124/22 2117.5129.5151 C Ex6 with less DME, worse oil miscibility, still usable in O
some systems 108 R-E170/142b/124/22 4121.5123.5141 A Ex6 with less R-22, lower pressures, usable in some systems 109 R-E170/142b/124/22 419121166 B- Ex6 with more R-22 higher pressures, usable in some systems 110 R-600a/142b/124/125 8116130146 A 15 Ex58 with more isobutane, weakly flari"l,able, still usable 111 R-600a/142b/124/125 2119133146 C 15 Ex58 with less isobutane, worse oil misc, usable in some systems 112 R-600a/142b/124/125 4123137136 A- 15 Ex58 with less R-125, lower pressures, usable in some systems c 113 R-600a/142b/124/125 4/11/24161 C- 15 Ex58 with more R-125, higher pressures, usable in some systems ,CX~

CA 02232674 l998-03-20 W O 97/11138 PCT~US96/14882 I

There exist thousands of possible combinations and permutations from ~ the refrigerant fluids listed in Tables 1-3 that could produce a refrigerant substitute for R-12. Many combinations can be ruled out under conditions 1,2, and 3 listed above. Other combinations may still provide a good refrigerant, but may not be currently environmentally acceptable. but they may become acceptable in the future as new evidence and understanding of the environment proceeds. In general, higher temperature applications (above 32 degrees Fahrenheit and above such as automotive air conditioning) may work with R-12 substitutes that have poor or l~laryi,,al oil 10 miscibility, whereas the same substitute may prove unacceptable in lower temperature applications such as freezers or refrigerators. Other combinations from Tables 1-3 may produce R-12 "drop-in" substitutes that have low critical temperatures, below about 215 degrees Fahrenheit, and still provide satisfactory performance in the majority of climales, but prove unsdLisractory in extreme heat or very high humidity climates.

For any given combination of components, from Tables 1-3, above, that produce a useable "drop-in" substitute for R-12, many permutations (ranges) of each component's weight percentage are possible. Work to date has shown that highly na,llnlable GROUP-B oil miscibility improvers (isobutane, dimethyl ether, propane, etc) still provide some oil miscibility improvement in concentrations as low as about 1 weight percent (see discussion in Condition 2, above). Highly nd,l"~able GROUP-B components may be further increased to about 10 w~eight percent if a weakly flar"",able refrigerant can be tolerated, giving a range of about 1 to 10 weight percent in most cases for a useable "drop-in" substitute for R-12. GROUP-C
~ components (see discussion in Condition 1, above), may be varied over the range of about -10 to +15 weight percent from their "normal centerline" values W O 97/11138 PCT~US96/14882 used to create a normal temperature-pressure curve. This allows for special uses such as "low capacity" and "high capacity" refrigerant mixtures.
Adjustment of weight percentages of GROUP-C components, must be accompanied by a corresponding opposite adjustment in GROUP-A
components so that the total of all weight percentages remains at 100 percent. Examples 98-113 in Table 6, above, illustrate component ranges applied to Examples 1, 4, and 6, also in Table 6.

~ppendix A

The oil miscibility test stand consists of:
10 A refrigeration test stand built from a new two-ton medium temperature R-12 semi-hermetic Copeland compressor, model EAL2-0200-CAB. A standard two ton condenser (R-22) and fan were salvaged from a residential central air conditioning system. The oil test stand is a standard refrigeration system consisting of a compressor, a condenser, a refrigerant metering device (manual expansion valve) and an evaporator. The object of said test stand is to try to force oil logging (poor oil return) to occur in order to evaluate the oil return capabilities of test refrigerant mixtures under worst case conditions.
The evaporator is a 50 foot coil of 518" refrigeration copper tubing, in free air, with no fan or fins. The coil diar"eter is around 14 inches and is spread out to be about 2 1/2 feet deep. The centerline of the coil is parallel to the ground, providing each loop (11 of them) a chance to "trap" oil. There are six refrigeration sight gl~sses, or viewing ports in the refrigeration circuit.
They are located, in the liquid line, just before the refrigerant metering (expansion) needle valve, just aKer the metering valve, midway in the evaporator, at tne bottom of the center turn of pipe, at the evaporator outlet, in the center of the 6 foot vertical riser 7/8" suction line, and in the center of the 6 foot horizontal suction line run.

, W O 97/11138 PCT~US96/14882 Evaporator heat can be provided from direct electric heating of the coil, up to 310 Amps, approximately 5 volts from a variable DC power supply. The liquid line has a 1 foot rubber hose (automotive barrier hose) segment to block current flow through the condenser and compressor.

The (hand operated) metering device is a multiturn needle valve, approximately 4 tons capacity wide open.

The suction line, is a 6 foot piece of 7/8" vertical (straight up) copper, followed, by a 6 foot horizontal run (also 7/8"). The horizontal run has a "low spot", about 1 inch lower than the ends, for oil to collect in (and a sight glass).
o There is also a manual EPR (evaporator pressure regulator - ball valve, with 3/4" opening), with low side gauges on either side of the valve.

Claims (75)

What is claimed is:

1. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 7 to 34 weight percent 1-chloro-1,1-difluoroethane, about 5 to 50 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, and about 35 to 75 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture.

2. The mixture of refrigerants of claim 1 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 13 to 16.5 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 28.5 to 33 weight percent, and chlorodifluoromethane is present in about 50 to 51 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

3. The mixture of refrigerants of claim 1 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 34 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 7 weight percent, and chlorodifluoromethane is present in about 55 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

4. The mixture of refrigerants of claim 1 in which isobutane is present in about 1.5 weight percent, 1-chloro-1,1-difluoroethane is present in about 9.5 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 39 weight percent, and chlorodifluoromethane is present in about 50 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

5. The mixture of refrigerants of claim 1 in which isobutane is present in about 3 to 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 14.5 to 18 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 20.5 to 24 weight percent, and chlorodifluoromethane is present in about 55 to 61 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

6. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigerant systems, comprising about 1 to 10 weight percent isobutane, about 5 to 25 weight percent 1-chloro-1,1-difluoroethane, about 15 to 60 weight percent heptafluoropropane, and about 21 to 75 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture.

7. The mixture of refrigerants of claim 6 in which isobutane is present in about 4 weight percent isobutane, 1-chloro-1,1-difluoroethane is present in about 15 weight percent, heptafluoropropane is present in about 40 weight percent, and chlorodifluoromethane is present in about 41 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

8. The mixture of refrigerants of claim 6 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 15 weight percent, heptafluoropropane is present in about 30 weight percent, and chlorodifluoromethane is present in about 51 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

9. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigerant systems, comprising about 1 to 10 weight percent isobutane, about 8 to 30 weight percent 1-chloro-1,1-difluoroethane, about 9 to 50 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 28 to 70 weight percent chlorodifluoromethane, and about 1 to 20 weight percent of a refrigerant selected from the group consisting of heptafluoropropane, propane, propylene, and dimethyl ether, with the weight percentages of said components being weight percentages of the overall mixture.

10. The mixture of refrigerants in claim 9 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 15 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 17 weight percent, chlorodifluoromethane is present in about 44 weight percent, and heptafluoropropane is present in about 20 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

11. The mixture of refrigerants of claim 9 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 16 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 22 to 32 weight percent, chlorodifluoromethane is present in about 44 to 54 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

12. The mixture of refrigerants in claim 9 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 16 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 33 weight percent, chlorodifluoromethane is present in about 43 weight percent, and propylene is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

13. The mixture of refrigerants of claim 9 in which isobutane is present in about 2 weight percent, 1-chloro-1,1-difluoroethane is present in about 17 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 29 weight percent, chlorodifluoromethane is present in about 50 weight percent, and dimethyl ether is present in about 2 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

14. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 5 to 35 weight percent 1-chloro-1,1,-difluoroethane, about 10 to 40 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 30 to 70 weight percent chlorodifluoromethane, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane and methyl trifluoromethyl ether with the weight percentages of said components being weight percentages of the overall mixture.

15. The mixture of refrigerants of claim 14 in which dimethyl ether is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 14.5 to 16.5 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 20.5 to 28.5 weight percent, and chlorodifluoromethane is present in about 51 to 61 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

16. The mixture of refrigerants of claim 14 in which dimethyl ether is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 17 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 29 weight percent, chlorodifluoromethane is present in about 46 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

17. The mixture of refrigerants of claim 14 in which dimethyl ether is present in about 5 weight percent, 1-chloro-1,1-difluoroethane is present in about 12 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 28 weight percent, chlorodifluoromethane is present in about 50 weight percent, and methyl trifluoromethyl ether is present in about 5 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

18. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 28 to 58 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 5 to 30 weight percent 1,1,1,2-tetrafluoroethane, about 4 to 28 weight percent 1,1,1-trifluoroethane, about 4 to 28 weight percent pentafluoroethane, and about 1 to 20 weight percent hexafluoropropene, with the weight percentages of said components being weight percentages of the overall mixture.

19. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 5 to 30 weight percent 1-chloro-1,1-difluoroethane, about 5 to 30 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 10 to 45 weight percent 1,1,1,2-tetrafluoroethane, about 1 to 10 weight percent propane, and about 20 to 60 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture.

20. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent propane, about 20 to 60 weight percent 1-chloro-1,1-difluoroethane, about 30 to 74 weight percent chlorodifluoromethane, and about 0 to 10 weight percent isobutane, with the weight percentages of said components being weight percentages of the overall mixture.

21. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 5 to 30 weight percent 1-chloro-1,1-difluoroethane, about 15 to 50 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 30 to 60 weight difluoromethyltrifluoromethyl ether, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of the overall mixture.

22. The mixture of refrigerants of claim 21 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 16 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 33 weight percent, difluoromethyltrifluoromethyl ether is present in about 43 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

23. The mixture of refrigerants of claim 21 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 16 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 32 weight percent, difluoromethyltrifluoromethyl ether is present in about 44 weight percent, and propylene is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

24. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising 1 to 10 weight percent isobutane, about 32 to 65 weight percent 1-chloro-1,1-difluoroethane, about 29 to 65 weight percent pentafluoroethane, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene with the weight percentages of said components being weight percentages of the overall mixture.

25. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 6 to 31 weight percent 1-chloro-1,1-difluoroethane, about 20 to 65 weight percent heptafluoropropane, and about 22 to 58 weight percent pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

26. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 31 to 60 weight percent 1-chloro-1,1-difluoroethane, about 15 to 40 weight percent chlorodifluoromethane, about 13 to 38 weight percent pentafluoroethane, and about 1 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene with the weight percentages of said components being weight percentages of the overall mixture.

27. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 15 to 58 weight percent 1-chloro-1,1-difluoroethane, about 4 to 20 weight percent 1,1,1,2-tetrafluoroethane, about 30 to 60 weight percent chlorodifluoromethane, and about 1 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of the overall mixture.

28. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 30 to 65 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 28 to 67 weight percent chlorodifluoromethane, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane an propylene, with the weight percentages of said components being weight percentages of the overall mixture.

29. The mixture of refrigerants of claim 28 in which isobutane is present in about 4 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 52 weight percent, chlorodifluoromethane is present in about 40 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

30. The mixture of refrigerants of claim 28 in which isobutane is present in about 4 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 53 weight percent, chlorodifluoromethane is present in about 39 weight percent, and propylene is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

31. The mixture of refrigerants of claim 28 in which isobutane is present in about 6 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 48 weight percent, chlorodifluoromethane is present in about 42 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

32. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 41 to 85 weight percent heptafluoropropane, about 8 to 40 weight percent chlorodifluoromethane, about 1 to 10 weight percent propane, and about 0 to 25 weight percent 1,1,1,2-tetrafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

33. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 50 to 78 weight percent 1,1,1,2,2-pentafluoropropane, about 15 to 55 weight percent chlorodifluoromethane, and about 1 to 10 weight percent propane, with the weight percentages of said components being weight percentages of the overall mixture.

34. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 25 to 60 weight percent 1-chloro-1,1-difluoroethane, about 30 to 76 weight percent chlorodifluoromethane, and about 1 to 10 weight percent of a refrigerant from the group consisting of isobutane and propane.

35. The mixture of refrigerants of claim 34 in which dimethyl ether is present in about 2 weight percent, isobutane is present in about 2 weight percent, 1-chloro-1,1-difluoroethane is present in about 41 weight percent, and chlorodifluoromethane is present in about 55 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

36. The mixture of refrigerants of claim 34 in which dimethyl ether is present in about 4 weight percent, 1 -chloro-1,1-difluoroethane is present in about 41 weight percent, chlorodifluoromethane is present in about 61 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

37. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 34 to 76 weight percent heptafluoropropane, about 10 to 35 weight percent pentafluoroethane, about 1 to 10 weight percent propane, and about 5 to 30 weight percent of a refrigerant selected from the group consisting of 1,1,1-trifluoroethane and 1,1,1,2-tetrafluoroethane, with the weight percentages of said mixture being weight percentages of the overall mixture.

38. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerants in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 55 to 85 weight percent heptafluoropropane, about 9 to 37 weight percent pentafluoroethane, and about 1 to 10 weight percent propane, with the weight percentages of said components being weight percentages of the overall mixture.

39. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 32 to 76 weight percent heptafluoropropane, about 10 to 32 weight percent 1,1,1,2-tetrafluoroethane, about 1 to 10 weight percent propane, and about 9 to 31 weight percent of a refrigerant selected from the group consisting of 1,1,1-trifluoroethane and pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

40. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems. comprising about 1 to 10 weight percent isobutane, about 28 to 63 weight percent 1-chloro-1,1-difluoroethane, about 37 to 71 weight percent difluoromethyltrifluoromethyl ether, and about 0 to 8 weight percent propane, with the weight percentages of said components being weight percentages of said overall mixture.

41. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 8 to 35 weight percent 1-chloro-1,1-difluoroethane, about 12 to 51 weight percent 2-chloro-1, 1,1,2-tetrafluoroethane, about 29 to 63 weight percent pentafluoroethane and about 0 to 10 weight percent propane, with the weight percentages of said components being weight percentages of the overall mixture.

42. The mixture of refrigerants of claim 41 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 18 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 32 weight percent, and pentafluoroethane is present in about 46 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

43. The mixture of refrigerants of claim 41 in which isobutane is present in about 4 weight percent, 1-chloro-1,1-difluoroethane is present in about 18 weight percent, 2-chloro-1.1,1,2-tetrafluoroethane is present in about 32 weight percent, pentafluoroethane is present in about 42 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being the weight percentages of the overall mixture.

44. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 5 to 32 weight percent 1-chloro-1,1-difluoroethane, about 8 to 45 weight percent heptafluoropropane, about 6 to 35 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, and about 25 to 60 weight percent pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

45. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 30 to 74 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 22 to 66 weight percent pentafluoroethane, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of said overall mixture.

46. The mixture of refrigerants of claim 45 in which isobutane is present in about 8 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 51 weight percent, and pentafluoroethane is present in about 41 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

47. The mixture of refrigerants of claim 45 in which isobutane is present in about 6 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 54 weight percent, pentafluoroethane is present in about 36 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

48. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoroethane refrigerant in a dichlorodifluoromethane refrigeration system, comprising about 1 to 10 weight percent dimethyl ether, about 35 to 72 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 24 to 60 weight percent pentafluoroethane, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of the overall mixture.

49. The mixture of refrigerants of claim 48 in which dimethyl ether is present in about 8 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 51 weight percent, and pentafluoroethane is present in about 41 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

50. The mixture of refrigerants of claim 48 in which dimethyl ether is present in about 6 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 54 weight percent, pentafluoroethane is present in about 36 weight percent, and propane is present in about 4 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

51. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 12 weight percent dimethyl ether, about 31 to 67 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 28 to 65 weight percent chlorodifluoromethane, and about 0 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of the overall composition.

52. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 58 to 85 weight percent heptafluoropropane, about 9 to 35 weight percent pentafluoroethane, and about 1 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene with the weight percentages of said components being weight percentages of the overall mixture.

53. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 2 to 12 weight percent isobutane, about 19 to 48 weight percent neptafluoropropane, about 18 to 42 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, and about 20 to 55 weight percent pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

54. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 33 to 72 weight percent 1-chloro-1,1-difluoroethane, about 30 to 65 weight percent pentafluoroethane, and about 1 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of the overall mixture.

55. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 31 to 68 weight percent 1 -chloro-1,1-difluoroethane, about 25 to 62 weight percent pentafluoroethane, about 1 to 10 weight percent propane and about 0 to 20 weight percent 1,1,1,2-tetrafluoroethane, with the weight percentages of said components being the weight percentages of the overall mixture.

56. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoroethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 58 to 85 weight percent heptafluoropropane, about 8 to 35 weight percent pentafluoroethane, and about 1 to 10 weight percent propylene, with the weight percentages of said components being weight percentages of the overall mixture.

57. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 31 to 71 weight percent 1-chloro-1,1-difluoroethane, about 23 to 61 weight percent pentafluoroethane, about 1 to 10 weight percent propylene, and about 0 to 20 weight percent 1,1,1,2-tetrafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

58. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoroethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 15 to 59 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 10 to 59 weight percent 1,1,1,2-tetrafluoroethane, and about 15 to 54 weight percent of a refrigerant selected from the group consisting of chlorodifluoromethane, pentafluoroethane, and 1,1,1,-trifluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

59. The mixture of refrigerants of claim 58 in which isobutane is present in about 6 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 26 weight percent, 1,1,1,2-tetrafluoroethane is present in about 40 weight percent, and chlorodifluoromethane is present in about 28 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

60. The mixture of refrigerants of claim 58 in which isobutane is present in about 6 weight percent, 2-chloro-1,1,1,2-tetrafluoroethane is present in about 37 weight percent, 1,1,1,2-tetrafluoroethane is present in about 26 weight percent, and chlorodifluoromethane is present in about 28 weight percent, the weight percentages of said components being weight percentages of the overall mixture.

61. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 60 to 92 weight percent heptafluoropropane and about 8 to 40 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture.

62. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 27 to 67 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 1-chloro-1,1-difluoroethane, and about 18 to 58 weight percent pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

63. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 4 to 16 weight percent 1-chloro-1,1-difluoroethane, about 5 to 20 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, and about 60 to 90 weight percent perfluoropropane, with the weight percentages of said components being weight percentages of the overall mixture.

64. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 28 to 65 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 15 to 48 weight percent 1,1,1,2-tetrafluoroethane, and about 1 to 25 weight percent of a refrigerant selected from the group consisting of propane and pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

65. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 8 weight percent isobutane, about 24 to 61 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, about 14 to 40 weight percent 1,1,1,2-tetrafluoroethane, about 1 to 8 weight percent propane, and about 14 to 43 weight percent of a refrigerant selected from the group consisting of pentafluoroethane and chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture.

66. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 28 to 60 weight percent heptafluoropropane, about 8 to 33 weight percent 1-chloro-1,1-difluoroethane, and about 25 to 60 weight percent chlorodifluoromethane, with the weight percentages of said components being weight percentages of the overall mixture.

67. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent dimethyl ether, about 55 to 89 weight percent heptafluoropropane, and about 8 to 43 weight percent of a refrigerant selected from the group consisting of chlorodifluoromethane, pentafluoroethane, and 1,1,1-trifluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

68. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 15 to 48 weight percent 1-(trifluoromethoxy)-1,1,2,2-tetrafluoroethane, about 1 to 10 weight percent isobutane, about 52 to 80 weight percent perfluoropropane, and about 1 to 10 weight percent of a refrigerant selected from the group consisting of propane and propylene, with the weight percentages of said components being weight percentages of the overall mixture.

69. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 18 to 40 weight percent octafluorocyclobutane, about 1 to 10 weight percent dimethyl ether, about 51 to 86 weight percent perfluoropropane, and about 1 to 10 weight percent propane, with the weight percentages of said components being weight percentages of the overall mixture.

70. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 1 to 10 weight percent isobutane, about 55 to 85 weight percent heptafluoropropane, and about 13 to 43 weight percent of a refrigerant selected from the group consisting of pentafluoroethane and 1,1,1,-trifluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

71. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 28 to 70 weight percent 1-chloro-1,1-difluoroethane and about 30 to 72 weight percent pentafluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

72. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 37 to 77 weight percent 1-chloro-1,1-difluoroethane and about 23 to 63 weight percent 1,1,1-trifluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

73. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 48 to 88 weight percent 2-chloro-1,1,1,2-tetrafluoroethane and about 12 to 52 weight percent 1,1,1-trifluoroethane, with the weight percentages of said components being weight percentages of the overall mixture.

74. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising about 0.5 to 8 weight percent isobutane, about 15 to 60 weight percent of a component B, and about 21 to 71 weight percent chlorodifluoromethane, with the weight percentages of the foregoing components being weight percentages of the overall mixture, wherein component B is about 99 weight percent 1-chloro-1,1-difluoroethane and about 1 to 99 weight percent of a component C, with the weight percentages of the subcomponents of component B being weight percentages of component B, wherein component C is about 0 to 100 weight percent heptafluoropropane and about 0 to 100 weight percent 2-chloro-1,1,1,2-tetrafluoroethane, with the weight percentages of the components of component C being weight percentages of component C.

75. A mixture of refrigerants that is a drop-in substitute for dichlorodifluoromethane refrigerant in dichlorodifluoromethane refrigeration systems, comprising one or more components from GROUP A of Table 4, zero or more components from GROUP B of Table 4, one or more components from GROUP C of Table 4, and zero or more components from GROUP D of Table 4, wherein the temperature versus pressure curve of a closed container of said mixture approximates, within about 15 to 30 percent error, the temperature versus pressure curve from about -40 °F to about 200 °F of a closed container of dichlorodifluoromethane refrigerant, and wherein said mixture is sufficiently miscible with the mineral oils within dichlorodifluoromethane refrigeration systems so as to provide adequate circulating of the oils throughout the systems, and wherein the maximum mass fraction of said components that are very flammable is about 5 to 10 percent and the maximum mass fraction of said components that are weakly flammable is about 15 to about 60 percent, and wherein any halocarbon component that is mixed with two hydrocarbon components, one having a higher and one having a lower boiling point than said halocarbon component, is at least a weakly flammable halocarbon, and wherein of any two halocarbon components that are mixed with a hydrocarbon component, that has a boiling point that is between the boiling points of said two halocarbon components, one of said halocarbon components is at a least weakly flammable halocarbon; said mixtures of refrigerants being mixtures other than those comprising about 2 to 20 weight percent isobutane, about 21 to 51 weight percent 1-chloro-1,1-difluoroethane, and about 41 to 71 weight percent chlorodifluoromethane, wherein the weight percentages are weight percentages of the overall mixtures.