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 AN INERT GAS”
SRF LIMITED, AN INDIAN COMPANY,
SECTOR 45, BLOK-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 an inert gas. 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. R23 is among the HFC refrigerants (hydrofluorocarbons, F-gases) that pose no threat to the ozone layer (ODP=0) but has high global warming potential (GWP) of 18,400. Due to its high GWP, R23 now has limited use in refrigeration industry.
Various compositions are known in the art which discloses compositions of R32 with other components such as R23, R125, R134a, CO2 and nitrogen gas e.g.,
U.S. Pat. No. 7708980 provides a propellant blend comprising from 10.1 weight % to 90 weight % 1,1,1,2-tetrafluoroethane; from 28 weight % to 9 weight % of carbon dioxide gas and from 1.6 weight % to 4 weight % nitrogen gas.
U.S. Pat. No. 6231781 provides a composition comprising from 10 to 80% by weight of R23, from 10 to 70% by weight of R32 and up to 50% by weight of one additional component such as R125.
U.S. Pat. No. 5744052 provides an azeotrope-like composition consisting essentially of 49-55 weight % difluoromethane, 40-49.5 weight % pentafluoroethane (R125) and about 0.5-3 weight % carbon dioxide, said composition having a liquid and a vapor phase, wherein when 50 weight % 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. 5,736,063 provides a refrigerant composition comprising from about 10 to about 90 weight % of difluoromethane; from about 1 to about 50 weight % of carbon dioxide; and from about 1 to about 50 weight % of pentafluoroethane, wherein said refrigerant compositions have a vapor pressure substantially equal to the vapor pressure of chlorodifluoromethane.
U.S. Pat. App. No. 20210189208 provides a mixed refrigerant that contains at least one fluorinated hydrocarbon selected from the group consisting of R32, R125, 1,1,1,2 tetrafluoroethane (R134a) and 1 mass % to 12 mass % of CO2 (R744) based on the entire refrigerant.
U.S. Pat. App. No. 20210179908 provides a refrigerant composition comprising carbon dioxide (CO2, R-744), R134a and from 1 to 32 weight % difluoromethane (R-32) based on the total weight of the refrigerant composition.
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.
So, there arises a need in the art to prepare a relatively low GWP refrigerant which can be used in low cooling applications.
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 an inert gas.

SUMMARY OF THE INVENTION
In an aspect, the present invention provides a composition, comprising from 8% by weight to 99.8% by weight of difluoromethane and from 0.2% by weight to 10% by weight of argon.
In another aspect, the present invention provides a composition, comprising from 8% by weight to 99.8% by weight of difluoromethane, from 0.2% by weight to 10% by weight of argon, and other components selected from a group consisting of carbon dioxide, pentafluoroethane and 1,1,1,2-tetrafluoroethane.

DETAILED DESCRIPTION OF THE INVENTION
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 embodiment, the inert gas is selected from a group consisting of argon, nitrogen, helium, xenon, and krypton.
In another embodiment, the inert gas is selected from a group consisting of argon and nitrogen.
In another embodiment, the present invention provides a non-flammable refrigerant composition comprising from 90% by weight to 99.8% by weight of difluoromethane and from 10% by weight to 0.2% by weight of an inert gas.
In another embodiment, the present invention provides a non-flammable refrigerant composition comprising from 8% by weight to 99.8% by weight of difluoromethane and from 0.2% by weight to 10% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 94% by weight to 99.5% by weight of difluoromethane (R32) and from 0.5% by weight to 6% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 94% by weight to 96% by weight of difluoromethane (R32) and from 6% by weight to 4% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 96% by weight to 98% by weight of difluoromethane (R32) and from 4% by weight to 2% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 98% by weight to 99.5% by weight of difluoromethane (R32) and from 2% by weight to 0.5% by weight of argon.
In an embodiment, the present invention provides a composition comprising from 94% by weight to 99.5% by weight of difluoromethane (R32) and from 0.5% by weight to 6% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 94% by weight to 96% by weight of difluoromethane (R32) and from 6% by weight to 4% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 96% by weight to 98% by weight of difluoromethane (R32) and from 4% by weight to 2% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 98% by weight to 99.5% by weight of difluoromethane (R32) and from 2% by weight to 0.5% by weight of nitrogen.
In an embodiment, the present invention provides a composition comprising hydrofluoroalkanes, from 0.2% by weight to 10% by weight of an inert gas and from 10% by weight to 70% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 8% by weight to 45% by weight of difluoromethane (R32); from 0.2% by weight to 10% by weight of an inert gas; from 10% by weight to 70% by weight of carbon dioxide and from 20% by weight to 45% by weight of one or more components selected from pentafluoroethane (R125) and 1,1,1,2-tetrafluoroethane (R134a).
In an embodiment, the present invention provides a composition comprising from 40% by weight to 43% by weight of difluoromethane, from 40% by weight to 43% by weight of pentafluoroethane, from 2% by weight to 4% by weight of argon, and from 14% by weight to 16% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 37% by weight to 39% by weight of difluoromethane, from 37% by weight to 39% by weight of pentafluoroethane, from 3% by weight to 5% by weight of argon, and from 19% by weight to 21% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 34% by weight to 36% by weight of difluoromethane, from 34% by weight to 36% by weight of pentafluoroethane, from 4% by weight to 6% by weight of argon, and from 24% by weight to 26% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 14% by weight to 16% by weight of difluoromethane, from 22% by weight to 24% by weight of R134a, from 0.2% by weight to 0.7% by weight of argon, and from 60% by weight to 62% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 9% by weight to 11% by weight of difluoromethane, from 34% by weight to 36% by weight of R134a, from 4% by weight to 6% by weight of argon, and from 48% by weight to 52% by weight of carbon dioxide.
In an embodiment, the present invention provides a composition comprising from 40% by weight to 43% by weight of difluoromethane, from 40% by weight to 43% by weight of pentafluoroethane, from 2% by weight to 4% by weight of nitrogen, and from 14% by weight to 16% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 37% by weight to 39% by weight of difluoromethane, from 37% by weight to 39% by weight of pentafluoroethane, from 3% by weight to 5% by weight of nitrogen, and from 19% by weight to 21% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 34% by weight to 36% by weight of difluoromethane, from 34% by weight to 36% by weight of pentafluoroethane, from 4% by weight to 6% by weight of nitrogen, and from 24% by weight to 26% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 14% by weight to 16% by weight of difluoromethane, from 22% by weight to 24% by weight of R134a, from 0.2% by weight to 0.7% by weight of nitrogen, and from 60% by weight to 62% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 9% by weight to 11% by weight of difluoromethane, from 34% by weight to 36% by weight of R134a, from 4% by weight to 6% by weight of nitrogen, and from 48% by weight to 52% by weight of carbon dioxide.
In an embodiment, the present invention provides a composition comprising from 68% by weight to 84% by weight of difluoromethane, from 0.2% by weight to 10% by weight of an inert gas and from 10% by weight to 30% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 68% by weight to 84% by weight of difluoromethane, from 2% by weight to 10% by weight of argon and from 10% by weight to 30% by weight of carbon dioxide.
In another embodiment, the present invention provides a composition comprising from 70% by weight to 82% by weight of difluoromethane (R32); from 25% by weight to 15% by weight of carbon dioxide and from 5% by weight to 3% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 81% by weight to 83% by weight of difluoromethane (R32); from 14% by weight to 16% by weight of carbon dioxide and from 2.5% by weight to 3.5% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 74% by weight to 77% by weight of difluoromethane (R32); from 19% by weight to 21% by weight of carbon dioxide and from 3.5% by weight to 4.5% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 68% by weight to 72% by weight of difluoromethane (R32); from 24% by weight to 26% by weight of carbon dioxide and from 4.5% by weight to 5.5% by weight of argon.
In an embodiment, the present invention provides a composition comprising from 68% by weight to 84% by weight of difluoromethane, from 2% by weight to 10% by weight of nitrogen and from 10% by weight to 30% by weight of carbon dioxide.
In an embodiment, the present invention provides a composition comprising from 70% by weight to 82% by weight of difluoromethane (R32); from 25% by weight to 15% by weight of carbon dioxide and from 5% by weight to 3% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 81% by weight to 83% by weight of difluoromethane (R32); from 14% by weight to 16% by weight of carbon dioxide and from 2.5% by weight to 3.5% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 74% by weight to 77% by weight of difluoromethane (R32); from 19% by weight to 21% by weight of carbon dioxide and from 3.5% by weight to 4.5% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 68% by weight to 72% by weight of difluoromethane (R32); from 24% by weight to 26% by weight of carbon dioxide and from 4.5% by weight to 5.5% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 46% by weight to 52% by weight of difluoromethane, from 46% by weight to 52% by weight of pentafluoroethane and from 0.2% by weight to 10% by weight of an inert gas.
In an embodiment, the present invention provides a composition comprising from 46% by weight to 50% by weight of difluoromethane, from 47% by weight to 51% by weight of pentafluoroethane and from 0.5% by weight to 6% by weight of an inert gas.
In another embodiment, the present invention provides a composition comprising from 46% by weight to 52% by weight of difluoromethane, from 46% by weight to 52% by weight of pentafluoroethane and from 0.2% by weight to 10% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 47% by weight to 48% by weight of difluoromethane, from 47% by weight to 50% by weight of pentafluoroethane and from 3% by weight to 6% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 48% by weight to 49% by weight of difluoromethane, from 48% by weight to 49% by weight of pentafluoroethane and from 2% by weight to 4% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 49% by weight to 50% by weight of difluoromethane, from 49% by weight to 50% by weight of pentafluoroethane and from 0.5% by weight to 2% by weight of argon.
In another embodiment, the present invention provides a composition comprising from 47% by weight to 48% by weight of difluoromethane, from 47% by weight to 50% by weight of pentafluoroethane and from 3% by weight to 6% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 48% by weight to 49% by weight of difluoromethane, from 48% by weight to 49% by weight of pentafluoroethane and from 2% by weight to 4% by weight of nitrogen.
In another embodiment, the present invention provides a composition comprising from 49% by weight to 50% by weight of difluoromethane, from 49% by weight to 50% by weight of pentafluoroethane and from 0.5% by weight to 2% by weight of nitrogen.
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 90% by weight to 99.8% by weight of difluoromethane and from 10% by weight to 0.2% by weight of an inert gas.
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 8% by weight to 99.8% by weight of difluoromethane and from 0.2% by weight to 10% by weight of argon.
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 8% by weight to 99.8% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; from 0% to 52% by weight of pentafluoroethane; from 0% to 70% by weight of carbon dioxide and from 0% to 40% 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 46% by weight to 52% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon, and from 30% by weight to 52% 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 from 68% by weight to 84% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; and from 10% by weight to 30% 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 68% by weight to 84% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; from 20% by weight to 40% by weight of 1,1,1,2-tetrafluoroethane; and from 10% by weight to 30% by weight of carbon dioxide.
In another embodiment, the present invention provides a refrigerant composition comprising hydrofluoroalkanes and an inert gas which is prepared by mixing these components to get a mixture, wherein the mixing is assisted with recirculation or agitators.
In another embodiment of this aspect, the present invention provides a refrigeration process using the refrigerant composition comprising the steps of:
a) condensing the refrigerant composition; and
b) evaporating the refrigerant composition.
The composition according to the present invention may additionally comprise 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 Argon
GWP Boiling
Point Molar
Mass
1 97 3 657 -129 51.6
2 99.5 0.5 674 -66 51.9
3 99 1 670 -84 51.9
4 98.5 1.5 667 -101 51.8
5 98 2 663 -114 51.7
6 97.5 2.5 660 -122 51.6
7 96.5 3.5 653 -134 51.5
8 96 4 650 -138 51.4
9 95.5 4.5 647 -140 51.3
10 95 5 643 -140 51.2
11 94.5 5.5 640 -140 51.2
12 94 6 636 -148 51.1

Table 2
Compositions R32 R125 Argon CO2
R134a
GWP
Boiling
Point
Molar
Mass
13 41 41 3 15 - 1592 -150 64.7
14 38 38 4 20 - 1482 -164 62.4
15 35 35 5 25 - 1371 -168 60.3
16 15 - 0.5 61.5 23 - - -
17 10 - 5 50 35 - - -

Table-3
Compositions R32 Argon CO2
GWP Boiling
Point Molar
Mass
18 82 3 15 570 -140 50.2
19 76 4 20 535 -150 49.6
20 70 5 25 499 -150 49.1

Table 4
Compositions R32 R125 Argon
GWP
Boiling
Point
Molar
Mass
21 47 50 3 1903 -88 71.7
22 49.75 49.75 0.5 1914 -68 72.3
23 49.5 49.5 1 1904 -88 72.0
24 49.25 49.25 1.5 1895 -106 71.7
25 49 49 2 1885 -119 71.4
26 48.75 48.75 2.5 1875 -127 71.1
27 48.5 48.5 3 1866 -130 70.8
28 48.25 48.25 3.5 1856 -130 70.6
29 48 48 4 1847 -148 70.3
30 47.75 47.75 4.5 1837 -148 70.0
31 47.5 47.5 5 1827 -151 69.7
32 47.25 47.25 5.5 1818 -153 69.5
33 47 47 6 1808 -154 69.2

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 5
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 7.4907 1045.6 22.781 196.18 504.16 1.7325
2 7.1783 1053.6 22.203 199.35 513.45 1.7429
3 7.2395 1052 22.316 198.7 511.59 1.7407
4 7.3014 1050.4 22.431 198.06 509.74 1.7386
5 7.3639 1048.8 22.546 197.43 507.88 1.7366
6 7.427 1047.2 22.663 196.8 506.02 1.7345
7 7.5552 1044 22.9 195.56 502.31 1.7305
8 7.6203 1042.3 23.021 194.94 500.45 1.7286
9 7.686 1040.7 23.143 194.33 498.58 1.7267
10 7.7525 1039.1 23.266 193.73 496.72 1.7248
11 7.8197 1037.5 23.391 193.13 494.86 1.723
12 7.8875 1035.9 23.516 192.54 493 1.7212

Table 6
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 1.2062 140.85 11.862 0.14394 0.0118
2 1.2434 144.51 11.757 0.14937 0.01158
3 1.2357 143.77 11.778 0.14827 0.01163
4 1.2282 143.03 11.799 0.14717 0.01167
5 1.2207 142.3 11.82 0.14609 0.01171
6 1.2134 141.57 11.841 0.14501 0.01176
7 1.1991 140.12 11.883 0.14288 0.01184
8 1.1921 139.41 11.904 0.14183 0.01189
9 1.1852 138.69 11.925 0.14079 0.01193
10 1.1784 137.98 11.946 0.13975 0.01197
11 1.1717 137.27 11.967 0.13872 0.01202
12 1.1651 136.57 11.988 0.13771 0.01206

Table 7
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 16.727 949.43 48.893 241.54 505.41 1.9362
2 16.02 959.09 47.59 244.91 514.66 1.9365
3 16.158 957.17 47.845 244.22 512.82 1.9363
4 16.298 955.24 48.103 243.54 510.97 1.9362
5 16.439 953.31 48.363 242.87 509.12 1.9362
6 16.582 951.37 48.626 242.2 507.27 1.9362
7 16.873 947.49 49.162 240.88 503.56 1.9363
8 17.021 945.54 49.435 240.23 501.71 1.9364
9 17.17 943.59 49.71 239.58 499.85 1.9365
10 17.321 941.64 49.989 238.94 497.99 1.9367
11 17.474 939.68 50.271 238.31 496.13 1.9369
12 17.628 937.72 50.556 237.68 494.27 1.9372

Table 8
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
1 1.5377 121.94 15.15 0.10876 0.01313
2 1.5929 125.23 15.047 0.11282 0.012869
3 1.5815 124.56 15.069 0.112 0.012921
4 1.5703 123.9 15.09 0.11118 0.012973
5 1.5593 123.24 15.11 0.11037 0.013025
6 1.5484 122.59 15.13 0.10956 0.013078
7 1.5272 121.29 15.17 0.10796 0.013183
8 1.5169 120.65 15.19 0.10717 0.013236
9 1.5067 120.01 15.21 0.10639 0.013289
10 1.4966 119.37 15.229 0.10562 0.013342
11 1.4868 118.74 15.249 0.10485 0.013396
12 1.4771 118.11 15.268 0.10408 0.013449

Table-9
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
13 9.4288 1107.2 35.362 197.99 419.83 1.632
14 10.417 1086.8 37.351 197.38 418.58 1.6741
15 11.513 1066.7 39.592 196.95 417.16 1.719
16 12.924 1023.7 37.312 200 452.36 2.0125
17 9.4146 1068.4 29.733 200 445.97 1.8733

Table 10
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
13 1.0668 103.45 13.25 0.13934 0.012914
14 1.0593 103.1 13.573 0.13275 0.013142
15 1.0565 102.57 13.904 0.12651 0.013364
16 1.0719 114.9 14.929 0.12821 0.01315
17 0.99445 112.01 14.315 0.14151 0.01289

Table 11
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
13 20.765 984.65 76.958 241.07 423.1 1.9031
14 22.874 959.65 81.624 241.68 421.09 1.9847
15 25.214 934.32 86.955 242.57 418.78 2.0777
16 29.564 884.45 86.394 253.7 451.43 2.5747
17 22.462 938.26 68.619 249.49 450.47 2.2617

Table 12
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
13 1.3728 87.725 17.129 0.09993 0.01458
14 1.3722 86.8 17.664 0.094487 0.014886
15 1.3807 85.669 18.244 0.08929 0.015195
16 1.4377 92.161 19.637 0.08697 0.01498
17 1.2408 91.104 17.999 0.09751 0.01445

Table 13
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 1035.100 118.670 200.000 337.640 1.853
18 9.0271 1023.5 26.196 197.11 495.78 1.8085
19 9.8171 1013.2 27.928 196.41 489.03 1.8342
20 10.709 1002.7 29.906 195.86 482.13 1.8625

Table 14
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 1.715 78.549 17.294 0.093 0.015
18 1.1766 135.67 12.585 0.1355 0.01214
19 1.1604 132.54 12.888 0.13077 0.01236
20 1.1479 129.41 13.206 0.12612 0.01258

Table 15
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
18 19.977 920.27 56.584 244.66 496.19 2.066
19 21.669 906.05 60.544 244.74 488.98 2.1224
20 23.575 891.21 65.106 245.06 481.5 2.1877

Table 16
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
18 1.5138 116.13 16.271 0.10068 0.013583
19 1.4988 112.86 16.748 0.096489 0.013856
20 1.4913 109.54 17.27 0.092323 0.01414

Table-17
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
21 7.4679 1156.1 31.841 197.28 411.53 1.5107
22 7.0505 1167.1 30.728 200.54 421.15 1.5191
23 7.1345 1164.1 30.882 199.87 419.78 1.5187
24 7.2193 1161.2 31.037 199.21 418.4 1.5184
25 7.305 1158.3 31.194 198.56 417.03 1.5181
26 7.3915 1155.3 31.353 197.92 415.65 1.5178
27 7.479 1152.4 31.514 197.3 414.26 1.5176
28 7.5672 1149.5 31.676 196.68 412.88 1.5173
29 7.6564 1146.5 31.84 196.06 411.49 1.5172
30 7.7465 1143.6 32.007 195.46 410.1 1.517
31 7.8375 1140.6 32.175 194.87 408.71 1.5168
32 7.9295 1137.7 32.345 194.28 407.31 1.5167
33 8.0223 1134.7 32.517 193.7 405.92 1.5166

Table 18
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
21 1.0792 99.448 12.478 0.15257 0.012534
22 1.1263 102.8 12.343 0.15986 0.012278
23 1.1174 102.36 12.367 0.15825 0.012326
24 1.1089 101.91 12.391 0.15665 0.012375
25 1.1006 101.47 12.415 0.15508 0.012424
26 1.0926 101.03 12.439 0.15352 0.012474
27 1.0848 100.6 12.462 0.15198 0.012525
28 1.0773 100.16 12.486 0.15046 0.012575
29 1.07 99.725 12.51 0.14896 0.012629
30 1.063 99.291 12.534 0.14748 0.012685
31 1.0562 98.858 12.558 0.14601 0.01274
32 1.0496 98.427 12.582 0.14456 0.012795
33 1.0432 97.997 12.607 0.14313 0.01285

Table 19
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
21 16.646 1041.1 68.861 237 416.47 1.2734
22 15.697 1055.2 66.323 240.4 426.02 1.7103
23 15.887 1051.8 66.678 239.74 424.64 1.7125
24 16.079 1048.3 67.037 239.09 423.25 1.7146
25 16.274 1044.9 67.401 238.45 421.85 1.7168
26 16.47 1041.5 67.769 237.81 420.46 1.7191
27 16.669 1038 68.142 237.19 419.06 1.7213
28 16.87 1034.6 68.52 236.58 417.66 1.7236
29 17.073 1031.1 68.903 235.97 416.25 1.7258
30 17.279 1027.7 69.29 235.38 414.85 1.7281
31 17.486 1024.2 69.682 234.79 413.44 1.7304
32 17.696 1020.7 70.078 234.21 412.02 1.7327
33 17.909 1017.2 70.48 233.64 410.61 1.735

Table 20
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
21 1.885 85.748 15.882 0.111 0.014
22 1.432 88.79 15.753 0.11679 0.01373
23 1.419 88.381 15.776 0.11561 0.0138
24 1.4064 87.973 15.8 0.11445 0.01386
25 1.3943 87.566 15.823 0.1133 0.01393
26 1.3827 87.161 15.846 0.11216 0.01399
27 1.3714 86.757 15.869 0.11104 0.01406
28 1.3605 86.355 15.892 0.10993 0.01412
29 1.3499 85.956 15.916 0.10884 0.01419
30 1.3397 85.558 15.939 0.10775 0.01426
31 1.3298 85.162 15.963 0.10668 0.01432
32 1.3202 84.768 15.987 0.10563 0.01439
33 1.3109 84.375 16.011 0.10458 0.01445

In an embodiment, the compositions of present invention have vapor phase enthalpy in the range of 405 to 520 kJ/kg.
In an embodiment, the compositions of present invention have liquid phase thermal conductivity in the range of 84 to 150 mW/m-K.
In an embodiment, the compositions of present invention have vapour pressure in the range of 7 to 30 bar_g, lower than the R23.
In an embodiment, the compositions of present invention have GWP in the range of 490 to 2000 and vapour pressure in the range of 7 to 30 bar_g.
In another embodiment, the compositions of the present invention have vapor phase enthalpy in the range of 405 to 520 kJ/kg; liquid phase thermal conductivity in the range of 84 to 150 mW/m-K; vapour pressure in the range of 7 to 30 bar g and GWP in the range of 490 to 2000.
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 which has a very high GWP of 18400, therefore are very environment friendly.
The inert gas as used in some of the compositions of present invention helps in achieving required pressure for cryogenic system. It has zero GWP and ODP. It is a non- toxic inert gas and does not affect the compressor oil.
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).
In an embodiment, some of the compositions of the present invention are non-flammable.
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.
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 for use as high-pressure refrigerant for very low temperatures, comprising from 8% by weight to 99.8% by weight of difluoromethane and from 0.2% by weight to 10% by weight of argon.
2. The composition as claimed in claim 1, comprising from 8% by weight to 99.8% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; from 0% to 52% by weight of pentafluoroethane; from 0% to 70% by weight of carbon dioxide and from 0% to 40% by weight of 1,1,1,2-tetrafluoroethane.
3. The composition as claimed in claim 2, comprising from 46% by weight to 52% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; and from 30% by weight to 52% by weight of pentafluoroethane.
4. The composition as claimed in claim 2, comprising from 68% by weight to 84% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; and from 10% by weight to 30% by weight of carbon dioxide.
5. The composition as claimed in claim 2, comprising from 68% by weight to 84% by weight of difluoromethane; from 0.2% by weight to 10% by weight of argon; from 20% by weight to 40% by weight of 1,1,1,2-tetrafluoroethane; and from 10% by weight to 30% by weight of carbon dioxide.
6. The composition as claimed in claim 1, wherein the compositions have vapor phase enthalpy in the range of 405 to 520 kJ/kg; liquid phase thermal conductivity in the range of 84 to 150 mW/m-K; vapour pressure in the range of 7 to 30 bar g and GWP in the range of 490 to 2000.
7. The composition as claimed in claim 1 are refrigerant compositions intended for 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 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.
9. The composition as claimed in claim 1 are 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.
10. The composition as claimed in claim 1, wherein the compositions are useful for R23 retrofitting without modification to the equipment.

Dated this 23rd day of June 2022.