DESC:FORM 2
THE PATENT ACT 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

“COMPOSITIONS COMPRISING HYDROFLUOROALKANES AND CARBON DIOXIDE”

SRF LIMITED, AN INDIAN COMPANY,
SECTOR 45, BLOCK-C, UNICREST BUILDING,
GURGAON – 122003,
HARYANA (INDIA)

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention provides a composition comprising hydrofluoroalkanes and carbon dioxide. These compositions have ability to provide relatively low temperature cooling and unexpectedly superior combination of properties.

BACKGROUND OF THE INVENTION
Trifluoromethane (R23) is used for very low temperature refrigeration. It is also used as a clean fire suppressant. R23 is most commonly used in cascade systems at an evaporating temperature of -60oC to -100oC and at a condensing temperature of approximately -10oC to -40oC. R23 is among the HFC refrigerants (hydrofluorocarbons, F-gases) that pose no threat to the ozone layer (ODP=0) but feature a significant global warming potential. The GWP of R23 is as high as 18,400. Due to its high GWP, R23 now has limited use in refrigeration industry.
So, there arises a need in the art to prepare a relatively low GWP refrigerant which can be used in low cooling applications.
U.S. Pat. No. 5744052 provides an azeotrope-like composition consisting essentially of 49-55 weight percent difluoromethane, 40-49.5 weight percent pentafluoroethane (R125) and about 0.5-3 weight percent carbon dioxide, said composition having a liquid and a vapor phase, wherein when 50 weight percent of an initial composition is evaporated the vapor pressure of the composition changes by less than about 10 percent and further wherein said composition is nonflammable in the vapor phase.
U.S. Pat. No. 7238299 provides a non-flammable heat transfer fluid consisting essentially of at least about 45 mol percent carbon dioxide (CO2) and not greater than about 55 mol percent of difluoromethane (HFC-32) in a R32: CO2 weight ratio of from about 0.4 to about 0.7. These compositions have a vapour pressure of at least about 200 psia at 40°F.
European Patent App. No. 3837329 provides a refrigerant composition comprising carbon dioxide (CO2, R744) and from 1 to 32 weight % difluoromethane (R-32) based on the total weight of the refrigerant composition.
U.S. Pat. No. 5,736,063 provides a refrigerant composition comprising from about 10 to about 90 weight percent of difluoromethane; from about 1 to about 50 weight percent of carbon dioxide; and from about 1 to about 50 weight percent of pentafluoroethane, wherein said refrigerant compositions have a vapor pressure substantially equal to the vapor pressure of chlorodifluoromethane.
The present invention provides refrigerant compositions which are replacements for trifluoromethane (R23). These compositions have improved efficiency and capacity as refrigerants for cooling and unexpectedly superior combination of properties.

OBJECT OF THE INVENTION
The main object of the present invention is to provide a composition comprising hydrofluoroalkanes and carbon dioxide.

SUMMARY OF THE INVENTION
In an aspect, the present invention provides a composition, comprising, from 12% by weight to 99% by weight of difluoromethane and from 1% by weight to 75% by weight of carbon dioxide.
In another aspect, the present invention provides a composition, comprising, from 12% by weight to 35% by weight of difluoromethane; from 30% by weight to 75% by weight of carbon dioxide; and from 12% by weight to 35% by weight of hydrofluoroalkanes selected from a group consisting of difluoromethane, pentafluoroethane and 1,1,1,2-tetrafluoroethane.
DETAILED DESCRIPTION OF THE INVENTION
As used herein, the term hydrofluoroalkane is selected from a group consisting of difluoromethane (R32) and pentafluoroethane (R125).
As used herein, the non-azeotropic composition is a mixture of two or more substances that behaves as a simple mixture rather than a single substance. One way to characterize a non-azeotropic composition is that the vapor produced by partial evaporation or distillation of the liquid has a substantially different composition as the liquid from which it was evaporated or distilled, that is, the admixture distills/refluxes with substantial composition change.
In an aspect, the present invention provides a composition, comprising, from 12% by weight to 35% by weight of difluoromethane, from 30% by weight to 75% by weight of carbon dioxide, and from 12% by weight to 35% by weight of hydrofluoroalkanes selected from a group consisting of difluoromethane (R32), pentafluoroethane (R125) and 1,1,1,2-tetrafluoroethane (R134a).
In an embodiment, the present invention provides a composition comprising, from 12% by weight to 35% by weight of difluoromethane, from 12% by weight to 35% by weight of pentafluoroethane and from 30% by weight to 75% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 15% by weight to 20% by weight of difluoromethane, from 15% by weight to 20% by weight of pentafluoroethane and from 60% by weight to 70% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 22% by weight to 28% by weight of difluoromethane, from 22% by weight to 28% by weight of pentafluoroethane and from 45% by weight to 55% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 29% by weight to 33% by weight of difluoromethane, from 29% by weight to 33% by weight of pentafluoroethane and from 35% by weight to 41% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 12% by weight to 25% by weight of difluoromethane, from 20% by weight to 35% by weight of 1,1,1,2-tetrafluoroethane and from 45% by weight to 65% by weight of carbon dioxide.
In an embodiment, the present invention provides a composition comprising, from 14% by weight to 16% by weight of difluoromethane, from 21% by weight to 24% by weight of 1,1,1,2-tetrafluoroethane and from 61% by weight to 63% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 16% by weight to 18% by weight of difluoromethane, from 24% by weight to 26% by weight of 1,1,1,2-tetrafluoroethane and from 57% by weight to 59% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 18% by weight to 20% by weight of difluoromethane, from 21% by weight to 23% by weight of 1,1,1,2-tetrafluoroethane and from 58% by weight to 60% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 19% by weight to 21% by weight of difluoromethane, from 31% by weight to 33% by weight of 1,1,1,2-tetrafluoroethane and from 47% by weight to 49% by weight of carbon dioxide.
In another aspect, the present invention provides a composition comprising, from 55% by weight to 99% by weight of difluoromethane and from 45% by weight to 1% by weight of carbon dioxide.
In an embodiment, the present invention provides a composition comprising, from 55% by weight to 70% by weight of difluoromethane and from 45% by weight to 30% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 60% by weight to 65% by weight of difluoromethane and from 40% by weight to 35% by weight of carbon dioxide.
In an embodiment, the present invention provides a composition comprising, from 70% by weight to 99% by weight of difluoromethane and from 30% by weight to 1% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 70% by weight to 80% by weight of difluoromethane and from 30% by weight to 20% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 80% by weight to 90% by weight of difluoromethane and from 20% by weight to 10% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising, from 90% by weight to 99% by weight of difluoromethane and from 10% by weight to 1% by weight of carbon dioxide.
In another embodiment, the present invention provides a non-flammable refrigerant composition intended to use as high-pressure refrigerant for very low temperatures, comprising from 12% by weight to 99% by weight of difluoromethane and 1% by weight to 75% by weight of carbon dioxide.
In another embodiment, the present invention provides a non-flammable refrigerant composition intended to use as high-pressure refrigerant for very low temperatures, comprising from 12% by weight to 99% by weight of difluoromethane and from 1% by weight to 75% by weight of carbon dioxide; from 0% to 35% by weight of 1,1,1,2-tetrafluoroethane and from 0% to 35% by weight of pentafluoroethane.
In another embodiment, the present invention provides a non-flammable refrigerant composition intended to use as high-pressure refrigerant for very low temperatures, comprising 35% by weight to 99% by weight of difluoromethane and 1% by weight to 70% by weight of carbon dioxide.
In another embodiment, the present invention provides a non-flammable refrigerant composition intended to use as high-pressure refrigerant for very low temperatures, comprising from 12% by weight to 25% by weight of difluoromethane; from 35% by weight to 70% by weight of carbon dioxide and from 15% to 35% by weight of 1,1,1,2-tetrafluoroethane.
In another embodiment, the present invention provides a non-flammable refrigerant composition intended to use as high-pressure refrigerant for very low temperatures, comprising from 15% by weight to 35% by weight of difluoromethane; from 45% by weight to 70% by weight of carbon dioxide and from 15% to 35% by weight of pentafluoroethane.
In another embodiment, the present invention provides a refrigerant composition selected from a group consisting of R32, CO2, R125 and R134a, which is prepared by mixing these components to get a mixture, wherein the mixing is assisted with recirculation or agitators.
In another embodiment, the present invention provides a refrigeration process using the refrigerant composition comprising the steps of:
condensing the refrigerant composition; and
evaporating the refrigerant composition.
The composition according to the present invention may additionally comprise only one refrigerant oil, or two or more refrigerant oils. The refrigerant oil is not limited and can be suitably selected from typically used refrigerant oils. When doing so, a refrigerant oil that is superior, for example, in miscibility with the mixture and action of improving the stability of the mixture can be suitably selected, as necessary.
The base oil of the refrigerant oil is preferably, for example, at least one member selected from the group consisting of polyalkylene glycols (PAG), polyol esters (POE), and polyvinyl ethers (PVE).
The refrigerant oil may further contain an additive in addition to the base oil. The additive may be at least one member selected from the group consisting of antioxidants, extreme - pressure additives, acid scavengers, oxygen scavengers, copper deactivators, rust inhibitors, oil agents, and antifoaming agents.
These compositions are used for cooling of objects or very small portions of objects to relatively low temperatures, sometimes referred to herein for the purposes of convenience, but not by way of limitation, as micro-freezing or deep-freezing applications, mainly in the range of -50 to -90°C. The objects to be cooled may include biological matter, electronic components, and the like.
In certain embodiments, the invention provides for selective cooling of a very small or even microscopic object to a very low temperature without substantially affecting the temperature of surrounding objects.
These compositions are advantageous in several fields, such as for example in electronics, where it may be desirable to apply cooling to a miniature component on a circuit board without substantially cooling adjacent components or in the field of medicine, where it may be desirable to cool miniature discrete portions of biological tissue to very low temperatures in the performance of medical treatments like cryosurgery (such as gynecology, dermatology, neurosurgery and urology), dental, and veterinary procedures, without substantially cooling adjacent tissues.
The quantity of various components as used in the present invention along with GWP, boiling points and molar mass are described in the table below.
Table 1
Compositions R32 R125 CO2
R134a
GWP
Boiling
Point
Molar
Mass
1 32 32 36 - 1267 -102 58.8
2 30.45 30.45 39.1 - 1211 -79 57.9
3 30.5 30.5 39 - 1212 -79 57.9
4 30 30 40 - 1194 -79 57.6
5 27.5 27.5 45 - 1103 -80 56.2
6 25 25 50 - 1012 -81 54.8
7 22.5 22.5 55 - 921 -82 53.5
8 20 20 60 - 829 -83 52.2
9 17.5 17.5 65 - 738 -84 51.0
10 15 15 70 - 647 -84 49.9
11 15 - 62 23 462.55 -83 52.0
12 19 - 59 22 473.63 -82 52.0
13 17 - 58 25 498.09 -82 52.9
14 20 - 48 32 599.4 -80 55.9

Table-2
Compositions R32 CO2
15 64 36
16 60.9 39.1
17 61 39
18 55 45
19 68 32
20 72 28
21 75 25
22 82 18
23 86 14
24 92 8
25 97 3
26 45 55
27 35 65

The various physical and environment properties of the compositions of the present invention and prior art composition i.e., R23 at different temperature are tabulated below.

Table-3
At 0°C Temperature
Compositions Vapour Pressure (bar_g) Liquid Phase Density (kg/m?) Vapor Phase Density (kg/m?) Liquid Phase Enthalpy (kJ/kg) Vapor Phase Enthalpy (kJ/kg) Liquid Phase Cp (kJ/kg-K)
R23 23.934 1035.1 118.67 200 337.64 1.8534
1 12.487 1072 42.314 200 431.02 1.8136
2 13.134 1063.9 43.783 200 431.62 1.8424
3 13.112 1064.2 43.734 200 431.6 1.8415
4 13.328 1061.6 44.228 200 431.78 1.8509
5 14.464 1049 46.855 200 432.64 1.899
6 15.703 1036.6 49.769 200 433.36 1.9486
7 17.051 1024.5 52.996 200 433.95 1.9999
8 18.513 1012.7 56.558 200 434.37 2.0529
9 20.091 1001.1 60.475 200 434.62 2.1075
10 21.785 989.86 64.757 200 434.68 2.164
11 13.008 1023.2 37.594 200 454.43 2.0146
12 12.56 1024.5 36.384 200 457.38 1.9954
13 11.94 1032.4 35.071 200 455.12 1.974
14 9.5017 1060.1 29.563 200 454.04 1.8704

Table 4
At 0°C Temperature
Compositions Vapor Phase Cp (kJ/kg-K) Liquid Phase Thermal Conductivity (mW/m-K) Vapor Phase Thermal Conductivity (mW/m-K) Liquid Phase Viscosity (cP) Vapor Phase Viscosity (cP)
R23 1.7152 78.549 17.294 0.092531 0.014941
1 1.1222 109.92 14.294 0.13247 0.013101
2 1.1317 110.17 14.484 0.13039 0.01317
3 1.1313 110.17 14.478 0.13046 0.013168
4 1.1347 110.24 14.541 0.1298 0.013191
5 1.1538 110.55 14.862 0.12662 0.013301
6 1.1773 110.76 15.202 0.12361 0.01341
7 1.2056 110.9 15.563 0.12075 0.013518
8 1.2395 110.96 15.949 0.11803 0.013626
9 1.2798 110.95 16.365 0.11544 0.013734
10 1.3275 110.87 16.813 0.11299 0.013844
11 1.0764 114.89 14.939 0.12805 0.013114
12 1.0789 116.24 14.767 0.12928 0.01301
13 1.0596 115.33 14.687 0.13127 0.012996
14 1.0195 115.31 14.117 0.14086 0.012704

Table 5
At 25°C Temperature

Compositions Vapour Pressure (bar_g) Liquid Phase Density (kg/m?) Vapor Phase Density (kg/m?) Liquid Phase Enthalpy (kJ/kg) Vapor Phase Enthalpy (kJ/kg) Liquid Phase Cp (kJ/kg-K)
R23 45.973 680.09 379.91 261.94 301.55 18.871
1 26.988 936.13 93.607 248.25 430.71 2.2346
2 28.295 925.56 97.176 249.11 430.53 2.2992
3 28.252 925.9 97.057 249.08 430.54 2.297
4 28.686 922.5 98.259 249.36 430.46 2.3187
5 30.95 905.51 104.68 250.82 429.88 2.4348
6 33.376 888.57 111.85 252.35 428.99 2.565
7 35.962 871.66 119.82 253.96 427.75 2.7124
8 38.699 854.74 128.67 255.67 426.13 2.8806
9 41.574 837.78 138.46 257.48 424.1 3.0745
10 44.567 820.72 149.26 259.41 421.63 3.3007
11 29.739 883.75 87.116 253.76 453.41 2.5803
12 28.65 888.86 83.729 253.15 456.77 2.5185
13 27.496 897.4 80.846 252.5 455.55 2.4723
14 22.338 934.68 67.479 249.39 457.78 2.237

Table 6
At 25°C Temperature

Compositions Vapor Phase Cp (kJ/kg-K) Liquid Phase Thermal Conductivity (mW/m-K) Vapor Phase Thermal Conductivity (mW/m-K) Liquid Phase Viscosity (cP) Vapor Phase Viscosity (cP)
R23 26.842 53.447 35.21 0.04428 0.02479
1 1.5346 90.709 19.287 0.09185 0.01497
2 1.5675 90.491 19.708 0.08991 0.01509
3 1.5663 90.498 19.694 0.08997 0.01508
4 1.578 90.419 19.836 0.08936 0.01512
5 1.6451 89.961 20.593 0.08635 0.01533
6 1.7296 89.403 21.446 0.08346 0.01555
7 1.8362 88.752 22.414 0.08066 0.01578
8 1.9711 88.015 23.523 0.07795 0.01604
9 2.1437 87.198 24.804 0.0753 0.01631
10 2.3673 86.307 26.299 0.07272 0.01662
11 1.4483 92.115 19.697 0.08682 0.01495
12 1.4407 93.885 19.406 0.08837 0.01479
13 1.3947 93.198 19.111 0.0898 0.01474
14 1.2828 94.797 17.856 0.09818 0.01424

Table 7
At 0°C Temperature
Compositions Vapour Pressure (bar_g) Liquid Phase Density (kg/m?) Vapor Phase Density (kg/m?) Liquid Phase Enthalpy (kJ/kg) Vapor Phase Enthalpy (kJ/kg) Liquid Phase Cp (kJ/kg-K)
R23 23.934 1035.1 118.67 200 337.64 1.8534
15 11.297 1006.6 31.658 200 493.8 1.9347
16 11.806 1002.9 32.872 200 491.74 1.9542
17 11.789 1003 32.832 200 491.81 1.9535
18 12.87 995.81 35.446 200 487.68 1.9929

Table 8
At 0°C Temperature
Compositions Vapor Phase Cp (kJ/kg-K) Liquid Phase Thermal Conductivity (mW/m-K) Vapor Phase Thermal Conductivity (mW/m-K) Liquid Phase Viscosity (cP) Vapor Phase Viscosity (cP)
R23 1.7152 78.549 17.294 0.092531 0.014941
15 1.2068 133.24 13.556 0.13121 0.01237
16 1.2095 132.24 13.737 0.1297 0.01245
17 1.2094 132.27 13.731 0.12975 0.01245
18 1.2178 130.31 14.098 0.12684 0.0126

Table 9
At 25°C Temperature
Compositions Vapour Pressure (bar_g) Liquid Phase Density (kg/m?) Vapor Phase Density (kg/m?) Liquid Phase Enthalpy (kJ/kg) Vapor Phase Enthalpy (kJ/kg) Liquid Phase Cp (kJ/kg-K)
R23 45.973 680.09 379.91 261.94 301.55 18.871
15 24.58 894 69.048 251.15 491.96 2.2849
16 25.617 888.06 71.858 251.73 489.41 2.3275
17 25.582 888.26 71.764 251.71 489.49 2.3261
18 27.766 876.5 77.849 252.91 484.26 2.4175

Table 10
At 25°C Temperature
Compositions Vapor Phase Cp (kJ/kg-K) Liquid Phase Thermal Conductivity (mW/m-K) Vapor Phase Thermal Conductivity (mW/m-K) Liquid Phase Viscosity (cP) Vapor Phase Viscosity (cP)
R23 26.842 53.447 35.21 0.04428 0.024792
15 1.6118 112.04 18.047 0.09481 0.013947
16 1.6279 110.8 18.394 0.093248 0.014061
17 1.6274 110.84 18.382 0.093298 0.014057
18 1.6685 108.4 19.116 0.090271 0.014289

In an embodiment, the compositions of present invention have GWP in the range of 270 to 1300.
In an embodiment, the compositions of present invention have vapour pressure in the range of 8 to 44.6 bar_g.
In an embodiment, the compositions of present invention have vapor phase enthalpy in the range of 420 to 500 kJ/kg.
In an embodiment, the compositions of present invention have liquid phase thermal conductivity in the range of 86 to 120 mW/m-K.
In another embodiment, the compositions of the present invention have GWP in the range of 270 to 1300; vapour pressure in the range of 8 to 44.6 bar_g; vapor phase enthalpy in the range of 420 to 500 kJ/kg and liquid phase thermal conductivity 86 to 120 mW/m-K.
In another embodiment, the compositions of present invention are useful for R23 retrofitting without modification to the equipment.
In another embodiment, the compositions of the present invention are nonflammable refrigerant compositions intended to use in low temperature systems at -35 °C to -50 °C and ultra-low temperature systems at -50 °C to -100 °C.
In another embodiment, the compositions of the present invention are nonflammable refrigerant compositions intended for use in ultra-low temperature systems at -50 °C to -100 °C, fitted with piston or rotary compressors.
In another embodiment, the compositions of the present invention are nonflammable refrigerant compositions, intended for use in cascade refrigeration system at an evaporating temperature of -60°C to -100°C and at a condensing temperature of approximately -10°C to -40°C. The cascade refrigeration systems are the combinations of single-stage refrigeration systems operating at successively lower temperatures using multiple compressors.
In another embodiment, the compositions of the present invention are nonflammable refrigerant compositions intended for use in environmental test chambers or other equipment such as thermal shock test machines, freeze dryers, ultra-low temperature equipment or cryogenic equipment, blood bank refrigerators, biochemical test chambers commonly used in scientific research refrigeration, medical refrigeration, life sciences industry for the production and storage of biological systems and in defense and space industries equipment.
The compositions of the present invention have higher vapor phase enthalpy and liquid phase thermal conductivity than the R23 composition. The higher vapour phase enthalpy means composition will take more heat from evaporator leading to higher refrigerating effect and thus better cooling. The higher the liquid phase thermal conductivity, the higher will be heat transfer capacity and thus better will be the cooling capacity. The compositions of the present invention have various properties which are better than the R23.
Coefficient of performance (COP) is the amount of heat removed divided by the required energy input to operate the cycle. The higher the COP, the higher is the energy efficiency. COP is directly related to the energy efficiency ratio (EER) that is the efficiency rating for refrigeration or air conditioning equipment at a specific set of internal and external temperatures.
The compositions of the present invention have very low GWP than the R23 composition.
The carbon dioxide as used in compositions of present invention is a non-toxic, fire-retardant natural gas, have low GWP and zero ODP (ozone depletion potential).
Due to very low GWP and ODP, the compositions of the present invention are very environment friendly.
Further, the compositions of present invention provide a rate of cooling which is comparable with the R23.
The compositions of the present invention are non-flammable.
It is against this and other backgrounds, which shall be filed in a detailed manner in complete specifications, in due course, the present invention is brought out and explained in following non-limiting examples.
It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention and specific examples provided herein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention that come within the scope of any claims and their equivalents.

EXAMPLE
The compositions of the present invention were prepared by adding different components in increasing order of vapour pressure and were analyzed using ASPEN and NIST-REFPROP.
,CLAIMS:WE CLAIM:
1. A non-flammable refrigerant composition intended to use as high-pressure refrigerant for very low temperatures comprising from 12% by weight to 99% by weight of difluoromethane and 1% by weight to 75% by weight of carbon dioxide.
2. The composition as claimed in claim 1, comprising from 12% by weight to 99% by weight of difluoromethane and from 1% by weight to 75% by weight of carbon dioxide; from 0% to 35% by weight of 1,1,1,2-tetrafluoroethane and from 0% to 35% by weight of pentafluoroethane.
3. The composition as claimed in claim 1, comprising 35% by weight to 99% by weight of difluoromethane and 1% by weight to 70% by weight of carbon dioxide.
4. The composition as claimed in claim 1, comprising from 12% by weight to 25% by weight of difluoromethane; from 35% by weight to 70% by weight of carbon dioxide and from 15% to 35% by weight of 1,1,1,2-tetrafluoroethane.
5. The composition as claimed in claim 1, comprising from 15% by weight to 35% by weight of difluoromethane; from 45% by weight to 70% by weight of carbon dioxide and from 15% to 35% by weight of pentafluoroethane.
6. The composition as claimed in claim 1, wherein the compositions have GWP in the range of 270 to 1300; vapour pressure in the range of 8 to 44.6 bar_g; vapor phase enthalpy in the range of 420 to 500 kJ/kg and liquid phase thermal conductivity 86 to 120 mW/m-K.
7. The composition as claimed in claim 1 are refrigerant compositions intended to use in low temperature systems at -35 °C to -50 °C and ultra-low temperature systems at -50 °C to -100 °C, fitted with piston or rotary compressors.
8. The composition as claimed in claim 1 are refrigerant compositions intended to use in cascade refrigeration system at an evaporating temperature of -60°C to -100°C and at a condensing temperature of approximately -10°C to -40°C.
9. The composition as claimed in claim 1 are non-flammable refrigerant compositions intended to use in environmental test chambers or other equipment such as thermal shock test machines, freeze dryers, ultra-low temperature equipment or cryogenic equipment, blood bank refrigerators, biochemical test chambers commonly used in scientific research refrigeration, medical refrigeration, life sciences industry for the production and storage of biological systems and in defense and space industries equipment.
10. The composition as claimed in claim 1, wherein the compositions are useful for R23 retrofitting without modification to the instrument.

Dated this 23rd day of June 2022.