COMPOSITIONS

Abstract

The invention provides a composition comprising (a) carbon dioxide (R-744, CO2); (b) difluoromethane (R-32); and (c) a third component selected from 1,1,1,2-tetrafluoroethane (R-134a), trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)), 2,3,3,3-tetrafluoropropene (R-1234yf), 1,1,1,2,3,3,3-heptafluoropropane (R-227ea) and mixtures thereof.

Description

COMPOSITIONS The present invention relates to compositions suitable for use as working fluids in air conditioning and refrigeration applications. The compositions described herein are particularly useful in heat pump water heaters, air conditioning systems for trains, buses, cars, and trucks, commercial refrigeration systems including supermarket display systems and cold storage rooms (such as walk-in coolers and freezers), and transport refrigeration systems. The inclusion or analysis of a previously published document or any background information in the descriptive report should not necessarily be interpreted as an acknowledgment that a document or background information is part of the state of the art or is common knowledge. Carbon dioxide (CO2, R-744) is gaining popularity as a low global warming potential (GWP) refrigerant for applications requiring a non-flammable refrigerant. These applications include air conditioning systems for trains, buses, cars, and trucks; heat pump-water heater systems; commercial refrigeration systems, including supermarket display systems and cold storage; and transport refrigeration systems installed in refrigerated trucks or shipping containers. CO2 has two main disadvantages compared to other fluorocarbon refrigerants used in the same applications. First, it has low energy efficiency at ambient temperatures above approximately 25 to 30 °C. Second, its operating pressures are much higher than those of traditional fluorocarbon-based systems. Non-flammable refrigerant mixtures comprising difluoromethane (R-32) and CO2 have been proposed (see Adams et al. (J. Chem. Eng. Data 16 (1971) 146-149) and US 7238299B, the contents of which are incorporated herein by reference in their entirety). Such non-flammable compositions may contain up to 60% by weight of R-32. However, although such binary refrigerant compositions are not flammable as formulated, they would still be considered flammable according to ASHRAE Standard 34 (2019). This is because the mixtures are not azeotropic. ASHRAE Standard 34 requires that the results of a series of vapor leak experiments be considered over a temperature range of -40°C to 60°C to determine if a leak can generate a composition more flammable than the composition as formulated. When this is done for non-flammable binary mixtures of R-32 with CO2, a vapor leak at 40°C will result in the generation of a flammable composition, as the more volatile CO2 is preferentially removed from the system, causing the remaining material to fractionate and contain more than 60% R-32. Therefore, it would be desirable to identify refrigerant compositions that address these problems, preferably while maintaining the non-flammability of pure CO2. Ideally, such compositions should also have a low GWP. In particular, a GWP of approximately 150 or less would be required under the European Union Fluorinated Gas Regulations for certain applications, such as air conditioning systems in passenger cars or self-contained refrigeration units. The present invention addresses the above and other deficiencies and needs by providing a composition comprising carbon dioxide (CO2, R-744), difluoromethane (R-32) and a third component selected from 1,1,1,2-tetrafluoroethane (R134a), trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)), 2,3,3,3-tetrafluoropropene (R-1234yf), 1,1,1,2,3,3,3-heptafluoropropane (R-227ea) and mixtures thereof. These compositions will henceforth be referred to as “the compositions of the (present) invention”. The present inventor discovered that relatively small amounts of other components (especially R-134a) can be added to CO2 and R-32 to ensure that the resulting mixture does not fractionate into a flammable composition when analyzed according to the ASHRAE Standard 34 protocol. Furthermore, small amounts of a flammable species (e.g., R-1132a) can also be added to the mixtures of the present invention without generating a flammable composition. The compositions of the present invention are believed to be particularly useful in heat transfer systems (e.g., refrigeration, air conditioning, and heat pump systems) that utilize a transcritical refrigeration cycle. The basic transcritical cycle consists of the following stages: (a) evaporation of a low-pressure liquid refrigerant to remove heat from a low-temperature fluid source (such as air); (b) compression of the resulting refrigerant vapor in a compressor to produce a hot, high-pressure gas; (c) cooling the high-pressure gas by heat exchange with a sink fluid, at a higher temperature than the source, to produce a refrigerant gas J7J «ηη / ζζηζ / E / γίΛΐ denser and colder at high pressure. This gas is believed to be a supercritical fluid, as it is above its critical temperature; and (d) expansion of the supercritical fluid through an expansion valve or other restriction device to give a two-phase mixture of liquid refrigerant with vaporized refrigerant at low pressure; this mixture is then fed back to the evaporator stage (a) to complete the cycle. Optionally, this cycle includes an internal heat exchange process between the hot, high-pressure gas exiting the gas cooler and the cold vapor flowing from the evaporator to the compressor. This process takes place in an internal heat exchanger (IHX) and increases the cooling capacity and efficiency of the cycle. Conveniently, this transcritical refrigeration cycle may also include a liquid accumulator located after the evaporator (and before the IHX, if one is used). This serves to retain excess refrigerant charge when the outside ambient temperature is such that the pressure in the gas cooler drops. It has also been found that the compositions of the present invention are suitable for use in such cycles, regardless of whether or not they incorporate IHX or accumulator characteristics. The compositions of the present invention will now be described in detail. According to the present invention, a composition comprising CO2, R-32 and a third component selected from 1,1,1,2-tetrafluoroethane (R-134a), trans1,3,3,3-tetrafluoropropene (R-1234ze(E)), 2,3,3,3-tetrafluoropropene (R-1234yf), 1,1,1,2,3,3,3-heptafluoropropane (R-227ea) and mixtures thereof is provided. In one aspect of the present invention, the third component is R-134a and one or more of R-1234yf, R-1234ze(E) and R-227ea. In another aspect of the present invention, the third component is R-134a, provided that the composition does not comprise 86% by weight of CO2 ± 1% by weight, 7% by weight of R-32 ± 1% by weight and 7% by weight of R-134a ± 1% by weight. In another aspect of the present invention, the third component is one or more of R1234yf or R-1234ze(E). In yet another aspect of the present invention, the third component is one or more of R-1234yf, R-1234ze(E) and R-227ea. Typically, the compositions of the present invention comprise approximately 62 or approximately 65 to approximately 98% by weight of CO2, such as / 7 / «nn / zznz / E / YiAi as approximately 69 or approximately 71 to approximately 97% by weight, for example, approximately 74 or approximately 77 to approximately 96% by weight or approximately 81 to approximately 96% by weight, optionally approximately 81 or approximately 84 to approximately 95% by weight. Typically, the compositions of the present invention comprise from approximately 1 to approximately 25% by weight of R-32, such as from approximately 2 to approximately 22% by weight, for example, from approximately 3 to approximately 19% by weight, optionally from approximately 4% by weight to approximately 15 or approximately 13% by weight or from approximately 5% by weight to approximately 11% by weight. Conveniently, the compositions of the present invention comprise from approximately 1 to approximately 20% by weight of the third component, such as from approximately 2 or approximately 3 to approximately 15% by weight, for example, from approximately 4 to approximately 13% by weight, optionally from approximately 5 to approximately 11% by weight. In one embodiment, the compositions of the invention comprise, optionally consist essentially of, from approximately 65 to approximately 95% by weight of CO2, from approximately 5 to approximately 15% by weight of R-32 and from approximately 2 to approximately 20% by weight of R-134a. In such compositions, CO2 is preferably present in an amount of approximately 70 to approximately 91% by weight, R-32 is present in an amount of approximately 6 to approximately 14% by weight, and R-134a is present in an amount of approximately 3 to approximately 16% by weight. For example, in such compositions, CO2 is present in an amount of approximately 72 to approximately 88% by weight, R-32 is present in an amount of approximately 8 to approximately 13% by weight, and R-134a is present in an amount of approximately 4 to approximately 15% by weight. The compositions of the present invention may further comprise 1,1-difluoroethylene (R-1132a). When present, the compositions of the present invention comprise from approximately 1 to approximately 20% by weight of R-1132a, such as from approximately 2 to approximately 15% by weight, for example, from approximately 3 to approximately 12% by weight or from approximately 4 or approximately 5 to approximately 10% by weight. 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ The compositions of the invention do not normally contain 1,1,2-trifluoroethylene (R1123). Various refrigerant compositions comprising R1123 are known in the art. Although one advantage of using R1123 in such compositions is that it provides a capacity similar to that of R32 while having a negligible GWP, it can only be safely used as a diluted component in many refrigerant compositions. It is believed that the inclusion of R1123 in the compositions of the present invention may cause problems with the stability of the compositions and, therefore, lead to safety concerns regarding the use of such compositions. Furthermore, during development, the present inventors have discovered that while the inclusion of R-1123 in the compositions of the invention provides similar capacity compared to using an equivalent molar amount of R-32, it reduces the energy efficiency of the compositions. Considering the overall environmental impact of a system using these compositions (which is a combination of the refrigerant leakage effect (direct greenhouse gas emissions) and the refrigerant's energy efficiency in generating CO2 emissions from fuel or energy use (indirect greenhouse gas emissions)), the marginal GWP reduction available from using R-1123 is more than offset by the reduction in energy efficiency. Accordingly, R-1123 is preferably not included in the compositions of the invention. Accordingly, in one embodiment, the compositions of the invention are substantially free of R-1123. For example, the compositions of the invention do not contain readily detectable R-1123. In a preferred embodiment, these compositions do not contain R-1123. In one aspect, the compositions of the invention do not contain 80% by weight of CO2. For example, when the composition of the invention contains from 1 to 15% by weight of R-32, from 1 to 15% by weight of R-227ea, and from 5 to 75% by weight of R-1234yf or R-1234ze (e.g., trans-R-1234ze), the composition does not contain 80% by weight of CO2. Preferably, such compositions contain more than 80% by weight of CO2, such as more than 81% or 82% by weight of CO2. In one embodiment, the compositions of the present invention consist essentially of the indicated components. By the expression "consist essentially of" we include the meaning that the compositions of the invention do not contain substantially any other component, particularly any additional (hydro)(fluoro) compounds (for example, (hydro)(fluoro)alkanes or (hydro)(fluoro)alkenes) known for use in the 171 Aᑷη / Zζηζ / E / YΙΛΙ heat transfer compositions. The expression consist of is included within the meaning of essentially consist of. In one embodiment, the compositions of the invention are substantially free of any component having heat transfer properties (other than the specified components). For example, the compositions of the invention may be substantially free of any other hydrofluorocarbon compound. By “substantially without” and “substantially free of” we include the meaning that the compositions of the invention contain 0.5% by weight or less of the indicated component, preferably 0.4%, 0.3%, 0.2%, 0.1% or less, based on the total weight of the compositions. As used herein, all % amounts mentioned in the compositions herein, included in the claims, are by weight based on the total weight of the composition, unless otherwise stated. By the term “approximately”, as used in relation to numerical values ​​of component quantities in % by weight, we include the meaning of ± 0.5% by weight, for example ± 0.2% by weight. For the avoidance of doubt, it should be understood that the upper and lower values ​​indicated for the ranges of the quantities of the components in the compositions of the invention described herein may be interchanged in any way, provided that the resulting ranges are within the broader scope of the invention. The compositions of the present invention have zero ozone depletion potential. Typically, the compositions of the invention have a global warming potential (GWP) of less than approximately 300, such as less than approximately 240, such as less than approximately 200, for example, less than approximately 160 or less than approximately 150, preferably less than approximately 145. Conveniently, the compositions of the invention have a reduced risk of flammability compared to R-1132a. Flammability can be determined in accordance with ASHRAE Standard 34 (e.g., ASHRAE Standard 34:2019), the full content of which is incorporated into this description by reference. In one respect, the compositions have one or more of (a) a higher lower flammability limit; (b) a higher ignition energy; (c) a higher auto-ignition temperature; or (d) a lower combustion rate compared to R-1132a alone. 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ Preferably, the compositions of the invention are less flammable compared to R-1132a in one or more of the following respects: lower flammability limit at 23°C; lower flammability limit at 60°C; width of the flammability range at 23°C or 60°C; auto-ignition temperature (thermal decomposition temperature); minimum ignition energy in dry air; or rate of combustion. The flammability limits and rate of combustion are determined in accordance with the methods specified in ASHRAE-34, and the auto-ignition temperature is determined in a 500 ml glass flask by the method of ASTM E659-78. In a preferred embodiment, the compositions of the invention are non-flammable as formulated and under the fractionation assumptions of ASHRAE Standard 34:2019. For example, the compositions of the invention, and preferably their formulations for worst-case flammability, are non-flammable at a test temperature of 60°C using the ASHRAE-34 methodology. Advantageously, vapor mixtures existing in equilibrium with the compositions of the invention at any temperature between approximately -20°C and 60°C are also non-flammable. In some applications, it may not be necessary for the formulation to be classified as nonflammable by the ASHRAE-34 methodology. It is possible to develop fluids whose flammability limits are sufficiently reduced in air to be safe for use in the application, for example, if it is not physically possible to produce a flammable mixture due to leakage of the refrigeration equipment charge into the surrounding area. A preferred example of such an assumption is where the composition is formulated to be nonflammable, but where applying the fractionation methodology of Standard 34 would result in a flammable “worst-case formulation for flammability”; however, this assumption is not considered relevant to the application.Similarly, preferred compositions are those that would be classified as non-flammable as formulated, but weakly flammable under fractionation (flammability class 1 / 2L) according to the ISO 817 classification standard. The compositions of the invention are believed to exhibit a completely unexpected combination of low / zero flammability, low GWP, improved lubricant miscibility properties, and enhanced performance properties when used in refrigeration systems, especially air conditioning systems. Some of these properties are explained in more detail below. 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ Typically, the compositions of the present invention have a critical temperature that is approximately equal to or greater than the critical temperature of CO2, for example, greater than approximately 40 °C. Conveniently, the compositions of the present invention have a volumetric cooling capacity that is within at least approximately 75% of that of CO2, such as within at least approximately 80%, for example, within at least approximately 90%. Advantageously, the compositions of the present invention have a coefficient of performance (COP) approximately equal to or greater than that of CO2. Typically, the compositions of the present invention operate at a lower pressure in a gas cooler and evaporator than CO2. Reducing these operating pressures can improve compressor efficiency and durability, for example, by reducing the absolute pressure differential across the compressor, which in turn reduces the load on the machine's bearings. Furthermore, this reduced pressure differential can improve the compressor's volumetric efficiency. Conveniently, the compositions of the present invention have a temperature glide (defined as the difference between the dew point and the inlet temperature) in an evaporator that is less than approximately 12 K, such as less than approximately 10 K, for example, less than approximately 8 K, preferably less than approximately 6 K. The compositions of the invention are normally suitable for use in existing equipment designs and are compatible with all classes of lubricants currently used with established HFC refrigerants and with R-744. They can optionally be stabilized or made compatible with mineral oils by the use of appropriate additives. Preferably, the lubricant is selected from mineral oil, silicone oil, polyalkylbenzenes (PAB), polyolesters (POE), polyalkylene glycols (PAG), polyalkylene glycol esters (PAG esters), polyvinyl ethers (PVE), poly(alpha-olefins) and combinations thereof, preferably where the lubricant is selected from PAG, POE, PVE and combinations thereof. Compositions comprising a lubricant and a composition of the invention typically exhibit improved miscibility compared to CO2 and the same lubricant. 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ Conveniently, a stabilizer is selected from diene-based compounds, phosphates, phenolic compounds and epoxides, and mixtures of these. In another aspect of the present invention, a use of a composition of the present invention as a working fluid in a heat transfer system is provided. Typically, the heat transfer system is a refrigeration system, heat pump, or air conditioning system. Preferably, the refrigeration system comprises a commercial refrigeration system (such as a supermarket display refrigeration system, a beverage cooler refrigeration system, a warehouse refrigeration system or a cold room refrigeration system), or a transport refrigeration system (for example, a refrigeration system installed in a refrigerated transport container or a refrigeration system installed in a vehicle). Conveniently, the heat pump system comprises a heat pump system with a water heater. Preferably, the air conditioning system comprises a mobile or transport air conditioning system, such as an air conditioning system for buses, cars, trains, or trucks. Advantageously, the heat transfer systems (e.g., refrigeration, heat pump and / or air conditioning) defined above function as transcritical heat transfer systems for at least part of the year. In some transcritical cycle technology applications, a single-stage vapor compression cycle is used, as is typical in mobile air conditioning applications. In other applications, gas compression is carried out in two stages, allowing efficient operation over a wide temperature range between the heat source and the heat sink. The compositions of the invention are believed to be suitable for use in both single-stage and two-stage compression cycles. In one aspect of the present invention, a use of the composition of the invention is provided as an alternative to an existing working fluid in a heat transfer device, such as a new heat transfer device designed to meet the same application requirements. Conveniently, the existing working fluid is R-410A or R-407C. In another aspect of the present invention, a heat transfer device comprising a composition of the present invention is provided. 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ Preferably, the heat transfer device is a transcritical heat transfer device, such as a transcritical refrigeration device, heat pump, or air conditioner. Optionally, the transcritical heat transfer device comprises an internal heat exchanger system (IHX). The transcritical heat transfer device may also comprise a liquid accumulator placed after the evaporator or, if the IHX is present, between the evaporator and the IHX. According to another aspect of the invention, a method for producing heat is provided comprising condensing or cooling a composition of the invention in the vicinity of an article to be heated. According to another aspect of the invention, a method for producing cooling is provided comprising evaporating a composition of the invention in the vicinity of an article to be cooled. All the chemicals described herein are commercially available. For example, fluorochemicals can be purchased from Apollo Scientific (UK). The compositions of the invention can be prepared by simply mixing CO2, R-32, and the third component (and optional components such as R-1132a and / or a lubricant) in the desired proportions. The compositions can then be added to a heat transfer device or used in any other manner as described herein. The present invention is illustrated by the following non-limiting examples. EXAMPLES The vapor-liquid equilibrium behavior of CO2 with R-32 and R-134a at specific temperatures is described in the academic literature. The vapor-liquid equilibrium behavior of CO2 with R-134a and of R-134a with CO2, R-32, and R-134a was experimentally studied in the temperature range of -40 °C to +70 °C using a constant-volume equilibrium apparatus. The resulting data were used to adjust the binary interaction parameters for each binary pair for use with the NIST software codes REFPROP9.1 and REFLEAK5.1. The measurement principle of this experimental work was the determination of the vapor pressure for a series of known compositions within a specified range. 171 Aᑷη / Zζηζ / E / YΙΛΙ of temperatures, followed by a regression to the thermodynamic model to minimize the difference between the calculated and observed pressure in the data set. Subsequently, a series of ternary compositions of CO2 / R-32 / R-134a were subjected to a fractionation evaluation following the general scheme given in ASHRAE Standard 34 and using the REFPROP property library to model the refrigerant behavior. The worst-case scenario was defined as isothermal vapor leakage at -40 °C from a cylinder initially charged with 90% of the maximum allowable fill volume. The leakage was modeled to simulate a 95% loss of the initial mass. The maximum allowable fill volume was determined using the liquid density calculated at the temperature specified in the standard for modeling fluids with a critical temperature below 54.4 °C. Figure 1 shows the maximum R-32 content that could be included in a composition without the fractionation generating a flammable composition based on the R-134a content (from 0 to 15% by weight). Standard refrigeration cycle modeling techniques were then used to estimate the performance of selected compositions of the invention in the range of approximately 4 to approximately 14 wt% R-134a. The R-32 content was selected according to Figure 1 to give a composition that would remain non-flammable under fractionation. The modeled cycle was a transcritical cycle that used an internal heat exchanger (IHX) to exchange heat between the gas leaving the gas cooler and the low-pressure steam leaving the evaporator. The performance of CO2 was also calculated as a comparative example. The cycle conditions were chosen to ensure that the CO2 was functioning as a transcritical refrigerant in the cycle. The gas cooler pressure in the cycle was optimized to maximize the coefficient of performance (COP) of the mixture. The following conditions were assumed for modeling purposes: 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ 171 Αηη / Ζζηζ / Ε / ΥΙΛΙ Air temperature rise over gas cooler 10 K Air temperature on 33 °C Air temperature off Approximate temperature 43 °C in gas cooler 4 K Capacity Average evaporation temperature 6 kW Evaporator superheat 7 °C Heat gain from suction line through IHX 0 K Isentropic efficiency 65% Table 1: Model input conditions The results are shown in Table 2 below. Performance data shows that the modeled ternary compositions have superior energy efficiency and reduced operating pressures compared to CO2. Furthermore, the GWP of the compositions is less than approximately 300. Furthermore, it can be seen that it is not desirable to add more than approximately 15% by weight of R-134a in these compositions because the temperature glide in the evaporator becomes greater than 11 K. The ternary compositions of the invention can be further enhanced by the addition of R-1132a, for example, by replacing a portion of the CO2 content with R-1132a so that the R-1132a content is between 1% and 15% by weight without generating a flammable composition during fractionation. The addition of R-1132a reduces the compressor discharge temperature and reduces temperature glide in the evaporator. The modeling results for a selected composition comprising R-1132a are shown in Table 3 below. 17.1 Αηη / Ζζηζ / Ε / ΥΙΛΙ Table 2: Compositions comprising CO2, R-32 and R-134a. 17.1 Αηη / Ζζηζ / Ε / ΥΙΛΙ Table 3: A composition comprising CO2, R-32, R-134a and R-1132a R744 65% R1132a 15% R32 10% R134a 10% COP 2.85 Qvol kJ / m3 11 531 Tdis °C 103.7 Pev bar 30.5 Peo bar 68.3 DTev K 7.8 COP relative to CO2 106.1% Capacity relative to CO2 79.5% GWP (AR5 basis) 198

Claims

1. A composition comprising: (a) carbon dioxide (R-744, CO2); (b) difluoromethane (R-32); and (c) a third component selected from 1,1,1,2-tetrafluoroethane (R-134a), irans-1,3,3,3-tetrafluoropropene (R-1234ze(E)), 2,3,3,3-tetrafluoropropene (R-1234yf), 1,1,1,2,3,3,3-heptafluoropropane (R-227ea) and mixtures thereof.

2. A composition according to claim 1, wherein the third component is R-134a and one or more of R-1234yf, R-1234ze(E) and R-227ea.

3. A composition according to claim 1, wherein the third component is R-134a, provided that the composition does not comprise 86 wt% CO2 ± 1 wt%, 7 wt% R-32 ± 1 wt% and 7 wt% R-134a ± 1 wt%.

4. A composition according to claim 1, wherein the third component is one or more of R-1234yf or R-1234ze(E).

5. A composition according to claim 1, wherein the third component is one or more of R-1234yf, R-1234ze(E) and R-227ea.

6. A composition according to any of the preceding claims comprising approximately 62 or approximately 65 to approximately 98% by weight of CO2, such as approximately 69 or approximately 71 to approximately 97% by weight, for example, approximately 74 or approximately 77 to approximately 96% by weight or approximately 81 to approximately 96% by weight, optionally approximately 81 or approximately 84 to approximately 95% by weight.

7. A composition according to any of the preceding claims comprising from approximately 1 to approximately 25% by weight of R-32, such as from approximately 2 to approximately 22% by weight, for example from approximately 3 to approximately 19% by weight, optionally from approximately 4% by weight to approximately 15 or approximately 13% by weight or from approximately 5% by weight to approximately 11% by weight.

8. A composition according to any of the preceding claims comprising from approximately 1 to approximately 20% by weight of the third component, such as from approximately 2 or approximately 3 to approximately 15% by weight, for example, from approximately 4 to approximately 13% by weight, optionally from approximately 5 to approximately 11% by weight. i7.i «ηη / ζζηζ / E / γίΛΐ 9. A composition according to claim 3 comprising, optionally consisting essentially of, from approximately 65 to approximately 95% by weight of CO2, from approximately 5 to approximately 15% by weight of R-32 and from approximately 2 to approximately 20% by weight of R-134a.

10. A composition according to claim 9 wherein CO2 is present in an amount of approximately 70 to approximately 91% by weight, R-32 is present in an amount of approximately 6 to approximately 14% by weight, and R-134a is present in an amount of approximately 3 to approximately 16% by weight; preferably wherein CO2 is present in an amount of approximately 72 to approximately 88% by weight, R-32 is present in an amount of approximately 8 to approximately 13% by weight, and R-134a is present in an amount of approximately 4 to approximately 15% by weight.

11. A composition according to any of the preceding claims, wherein the composition further comprises 1,1-difluoroethylene (R-1132a).

12. A composition according to claim 11 comprising from approximately 1 to approximately 20% by weight of R-1132a, such as from approximately 2 to approximately 15% by weight, for example, from approximately 3 to approximately 12% by weight or from approximately 4 or approximately 5 to approximately 10% by weight.

13. A composition according to any of the preceding claims, wherein the composition substantially does not comprise 1,1,2-trifluoroethylene (R-1123).

14. A composition according to any of the preceding claims consisting essentially of the indicated components.

15. A composition according to any of the preceding claims, wherein the composition is not flammable as formulated, such as wherein the composition is not flammable as determined in accordance with ASHRAE Standard 34:2019.

16. A composition according to any of the preceding claims having a global warming potential (GWP) of less than approximately 300, such as less than approximately 240, such as less than approximately 200, for example, less than approximately 160 or less than approximately 150, preferably less than approximately 145. 17.1 Aᶜ / Zᶜ / E / Yᶜ 17. A composition according to any of the preceding claims having a critical temperature that is approximately equal to or greater than the critical temperature of CO2, for example, greater than approximately 40 °C.

18. A composition according to any of the preceding claims, wherein the composition has a volumetric cooling capacity that is within at least approximately 75% of that of CO2, such as within at least approximately 80%, for example, within at least approximately 90%.

19. A composition according to any of the preceding claims, wherein the composition has a coefficient of performance (COP) that is equivalent to or greater than that of CO2.

20. A composition according to any of the preceding claims, wherein the composition has an operating pressure in a gas cooler or evaporator equal to or less than that of CO2.

21. A composition according to any of the preceding claims, wherein the composition has a temperature glide in an evaporator or condenser that is less than approximately 12 K, such as less than approximately 10 K, for example, less than approximately 8 K, preferably less than 6 K.

22. A composition comprising a lubricant and a composition according to any of the preceding claims, preferably wherein the lubricant is selected from mineral oil, silicone oil, polyalkylbenzenes (PAB), polyolesters (POE), polyalkylene glycols (PAG), polyalkylene glycol esters (PAG esters), polyvinyl ethers (PVE), poly(alpha-olefins) and combinations thereof.

23. A composition according to claim 22, wherein the lubricant is selected from PAG, POE, PVE and combinations thereof.

24. Use of a composition according to any of the preceding claims as a working fluid in a heat transfer system, such as a refrigeration system, heat pump or air conditioning system.

25. The use of claim 24, wherein the refrigeration system comprises a commercial refrigeration system, such as a supermarket display refrigeration system, a beverage cooler refrigeration system, a warehouse refrigeration system, or a cold room refrigeration system. 17.1 Aế / Zế / E / YếLI 26. The use of claim 24, wherein the refrigeration system comprises a transport refrigeration system, such as a refrigeration system installed in a refrigerated transport container or a refrigeration system installed in a vehicle.

27. The use of claim 24, wherein the heat pump system comprises a heat pump system with a water heater.

28. The use of claim 24, wherein the air conditioning system comprises a mobile or transport air conditioning system, such as an air conditioning system for buses, automobiles, trains or trucks.

29. The use of any of claims 24 to 28, wherein the heat transfer system operates as a transcritical heat transfer system for at least part of the year.

30. A heat transfer device comprising a composition as defined in any of claims 1 to 23.

31. A heat transfer device according to claim 30, wherein the heat transfer device is a transcritical heat transfer device, such as a transcritical refrigeration device, heat pump, or air conditioner.

32. Use of a composition according to any of claims 1 to 23 as an alternative to an existing working fluid in a heat transfer system.

33. Use according to claim 32, wherein the existing working fluid is R-410AO or R-407C.

34. A method for cooling an article comprising condensing a composition defined in any of claims 1 to 23 and subsequently evaporating the composition in the vicinity of the article to be cooled.

35. A method for heating an article comprising condensing a composition as defined in any of claims 1 to 23 in the vicinity of the article to be heated and subsequently evaporating the composition.