Mixed refrigerant composition and heat pump including the same

Abstract

To provide a mixed refrigerant composition with improved environmental friendliness, and a heat pump which includes the mixed refrigerant composition.SOLUTION: A mixed refrigerant composition according to exemplary embodiments includes carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf) and 1,1-difluoroethane (R-152a). A content of the carbon dioxide (R-744) may be 1 to 10 wt.% based on a total weight of the mixed refrigerant composition, and a content of the 2,3,3,3-tetrafluoropropene (R-1234yf) may be 65 to 95 wt.% based on the total weight of the mixed refrigerant composition, and a content of trifluoroiodomethane (R-13I1) may be 1 to 30 wt.% based on the total weight of the mixed refrigerant composition. A boiling point at 1 atm of the mixed refrigerant composition may be -65 to -30°C.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a composition comprising a refrigerant and a heat pump comprising the same. [Background technology]

[0002] A refrigerant is a substance used to remove heat from heat pumps used in air conditioners, refrigerators, cooling towers, etc. Examples of refrigerants include natural refrigerants, chlorofluorocarbon (CFC)-based refrigerants, hydrochlorofluorocarbon (HCFC)-based refrigerants, hydrofluorocarbon (HFC)-based refrigerants, and hydrofluoroolefin (HFO)-based refrigerants.

[0003] Recently, the types of heat pumps used indoors and outdoors have become more diverse, and there is a demand for compact heat pumps due to the development of electric vehicles, etc. In addition, since refrigerants containing chlorine (Cl) can cause damage to the ozone layer, attempts are being made to develop refrigerants that do not contain chlorine atoms.

[0004] For example, 2,3,3,3-tetrafluoropropene (R-1234yf), a type of hydrofluoroolefin refrigerant, does not contain chlorine atoms and therefore has a low global warming potential (GWP), making it widely used as a refrigerant in automobile air conditioners.

[0005] However, due to its low coefficient of performance (COP), 2,3,3,3-tetrafluoropropene requires an additional heat pump when used as a refrigerant in automobile air conditioners, resulting in low energy efficiency.

[0006] Therefore, there is a need to develop a refrigerant or combination of refrigerants that has a high coefficient of performance while reducing environmental pollution. Summary of the Invention [Problem to be solved by the invention]

[0007] One objective of the exemplary embodiments is to provide a mixed refrigerant composition that has improved environmental friendliness.

[0008] One object of the exemplary embodiment is to provide a heat pump comprising the mixed refrigerant composition and having improved cooling performance. [Means for solving the problem]

[0009] The mixed refrigerant composition according to the embodiment of the present disclosure includes carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a). The content of the carbon dioxide (R-744) is 1% by weight to 10% by weight based on the total weight of the mixed refrigerant composition, the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) is 65% by weight to 95% by weight based on the total weight of the mixed refrigerant composition, and the content of the 1,1-difluoroethane (R-152a) is 1% by weight to 30% by weight based on the total weight of the mixed refrigerant composition. The boiling point of the mixed refrigerant composition at 1 atm is -65°C to -30°C.

[0010] A mixed refrigerant composition according to an exemplary embodiment can consist of the carbon dioxide (R-744), the 2,3,3,3-tetrafluoropropene (R-1234yf), and the 1,1-difluoroethane (R-152a).

[0011] According to an exemplary embodiment, the content of the 1,1-difluoroethane (R-152a) may be 13% by weight to 25% by weight based on the total weight of the mixed refrigerant composition.

[0012] According to an exemplary embodiment, the content of the 1,1-difluoroethane (R-152a) may be 18% by weight to 23% by weight based on the total weight of the mixed refrigerant composition.

[0013] According to an exemplary embodiment, the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition may be 6 to 95.

[0014] According to an exemplary embodiment, the ratio of the content of 1,1-difluoroethane (R-152a) to the content of carbon dioxide (R-744) in the total weight of the mixed refrigerant composition may be 0.5 to 30.

[0015] According to an exemplary embodiment, the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the 1,1-difluoroethane (R-152a) in the total weight of the mixed refrigerant composition may be 2 to 19.

[0016] According to an exemplary embodiment, the critical temperature of the mixed refrigerant composition may be 90°C to 100°C.

[0017] According to an exemplary embodiment, the mixed refrigerant composition may have a critical pressure of 30 bar to 51 bar.

[0018] According to an exemplary embodiment, the mixed refrigerant composition may have a temperature glide of 3°C to 29°C at a pressure of 1.5 bar.

[0019] According to an exemplary embodiment, the mixed refrigerant composition may have a temperature glide of 2°C to 23°C at a pressure of 15 bar.

[0020] According to an exemplary embodiment, the mixed refrigerant composition may have a latent heat at -25°C of 150 kJ / kg to 250 kJ / kg.

[0021] According to an exemplary embodiment, the mixed refrigerant composition may have a Global Warming Potential (GWP) of 1-40.

[0022] A heat pump according to an embodiment of the present disclosure includes the mixed refrigerant composition described above. Effect of the Invention

[0023] The mixed refrigerant composition according to the exemplary embodiment can prevent the refrigerant contained in the mixed refrigerant composition from containing chlorine atoms (Cl), thereby suppressing environmental pollution such as ozone layer depletion.

[0024] The mixed refrigerant compositions according to the exemplary embodiments can evaporate from a liquid to a gas even at low temperatures to effectively reduce the ambient temperature.

[0025] In addition, the mixed refrigerant composition does not undergo a phase change to a supercritical state during operation of a cooling device such as an air conditioner, etc. This prevents a decrease in the condensation pressure of the compressor, and improves the coefficient of performance of a heat pump that contains the mixed refrigerant composition. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram illustrating mixed refrigerant flow for heat exchange in a cooling mode of a heat exchanger according to an exemplary embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating a mixed refrigerant flow for heat exchange in a heating mode of a heat exchanger according to an exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] According to an exemplary embodiment, there is provided a mixed refrigerant composition comprising carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a), as well as a heat pump comprising the mixed refrigerant composition.

[0028] DETAILED DESCRIPTION OF THE DISCLOSURE The present disclosure will now be described in detail, by way of example only, and is not limited to the specific embodiments illustratively described.

[0029] According to an exemplary embodiment, the refrigerant contained in the mixed refrigerant composition may be a refrigerant that does not contain a chlorine atom (Cl). Examples of refrigerants that do not contain a chlorine atom (Cl) include natural refrigerants, hydrofluorocarbon (HFC)-based refrigerants, and hydrofluoroolefin (HFO)-based refrigerants.

[0030] The natural refrigerants are not man-made compounds but are substances that occur naturally on Earth, and may include, for example, at least one of ammonia (R-717), carbon dioxide (R-744), propane (R-290), propylene (R-1270), and butane (R-600a).

[0031] The hydrofluorocarbon (HFC) refrigerant is a refrigerant composed of hydrogen atoms (H), fluorine atoms (F) and carbon atoms (C). Examples of the hydrofluorocarbon (HFC) refrigerant include difluoromethane (R-32), trifluoroiodomethane (R-13I1), 1,1-difluoroethane (R-152a), pentafluoroethane (R-125), 1,1,1-trifluoroethane (R-143a), trifluoromethane (R-23), fluoroethane (R-161), 1,1,1,2,3,3 ,3-heptafluoropropane (R-227ea), 1,1,1,2,3,3-hexafluoropropane (R-236ea), 1,1,1,3,3,3-hexafluoropropane (R-236fa), 1,1,1,3,3-pentafluoropropane (R-245fa), and 1,1,1,3,3-pentafluorobutane (R-365mfc).

[0032] The hydrofluoroolefin (HFO) refrigerant is a refrigerant composed of hydrogen atoms (H), fluorine atoms (F) and carbon atoms (C) and having at least one double bond between the carbon atoms. The hydrofluoroolefin (HFO) refrigerant may include, for example, at least one of 1,1,2-trifluoroethylene (R-1123), 2,3,3,3-tetrafluoropropene (R-1234yf), 1,3,3,3-tetrafluoropropene (R-1234ze), 1,2,3,3-tetrafluoropropene (R-1234ye), 3,3,3-trifluoropropene (R-1243zf), 1,1-difluoroethylene (R-1132a), and 1,2,3,3,3-pentafluoropropene (R-1225ye).

[0033] The mixed refrigerant composition according to the present disclosure includes carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a). The carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a) contained in the mixed refrigerant composition do not include a chlorine atom (Cl).

[0034] The carbon dioxide (R-744) is a type of natural refrigerant, and has an Ozone Depleting Potential (ODP) of 0 and a Global Warming Potential (GWP) of 1. In addition, the carbon dioxide (R-744) may be free of corrosiveness, toxicity, explosiveness, etc. By including the carbon dioxide (R-744) in the mixed refrigerant composition, the environmental friendliness and stability of the mixed refrigerant composition can be improved.

[0035] The 2,3,3,3-tetrafluoropropene (R-1234yf) is a type of hydrofluoroolefin (HFO) refrigerant, and has an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of 4 or less. In addition, the R-1234yf may have high thermal stability and latent heat of vaporization. By including the 2,3,3,3-tetrafluoropropene (R-1234yf) in the mixed refrigerant composition, the environmental friendliness, thermal stability, and refrigeration capacity of the mixed refrigerant composition can be improved.

[0036] The 1,1-difluoroethane (R-152a) is a type of hydrofluorocarbon (HFC) refrigerant, and has an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of 150 or less. The 1,1-difluoroethane (R-152a) may have a small molecular weight and a small saturation density. By including the 1,1-difluoroethane (R-152a) in the mixed refrigerant composition, the environmental friendliness of the mixed refrigerant composition can be improved. In addition, the low saturation density can reduce the discharge pressure in the compressor, and the enthalpy change at the same compression ratio can be increased. This can improve the refrigeration capacity of the mixed refrigerant composition.

[0037] In some embodiments, the mixed refrigerant composition may not contain any other refrigerants than carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a). For example, the mixed refrigerant composition may not contain additional hydrofluorocarbon (HFC)-based refrigerants such as difluoromethane (R-32) that have a high global warming potential. This can improve the environmental friendliness of the mixed refrigerant composition. For example, the mixed refrigerant composition may not contain additional hydrofluoroolefin (HFO)-based refrigerants such as 1,1-difluoroethylene (R-1132a) that are toxic. This can improve safety even if some of the mixed refrigerant composition flows out of the heat pump.

[0038] For example, the mixed refrigerant composition may consist of only carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a). This can prevent a decrease in thermal stability and chemical stability due to mixing of a refrigerant with low thermal or chemical stability. In addition, it can prevent a rise in condensation temperature due to mixing of a refrigerant with low vapor pressure, or a decrease in refrigeration capacity due to mixing of a refrigerant with low latent heat of vaporization.

[0039] According to an exemplary embodiment, the content of the carbon dioxide (R-744) may be 1% by weight to 10% by weight, 1% by weight to 8% by weight, 1% by weight to 6% by weight, or 1% by weight to 5% by weight based on the total weight of the mixed refrigerant composition. If the content of the carbon dioxide (R-744) is less than 1% by weight based on the total weight of the mixed refrigerant composition, the global warming potential (GWP) of the mixed refrigerant composition may increase. This may result in a decrease in environmental friendliness. If the content of the carbon dioxide (R-744) is more than 10% by weight based on the total weight of the mixed refrigerant composition, the refrigeration capacity of the mixed refrigerant composition may decrease. This may result in a decrease in the cooling performance of the mixed refrigerant composition. Within the above content range, the global warming potential (GWP) of the mixed refrigerant composition can be reduced while preventing a decrease in the refrigeration performance. This may result in an improvement in the environmental friendliness and cooling performance of the mixed refrigerant composition.

[0040] In some embodiments, the carbon dioxide (R-744) content may be 1.5% to 5%, 2% to 5%, 3% to 5%, 4% to 5%, or 4.5% to 5% by weight based on the total weight of the mixed refrigerant composition. Within the above content ranges, the environmental friendliness and cooling properties of the mixed refrigerant composition can be further improved.

[0041] According to an exemplary embodiment, the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) may be 65% by weight to 95% by weight, 70% by weight to 95% by weight, 70% by weight to 90% by weight, or 75% by weight to 90% by weight based on the total weight of the mixed refrigerant composition. If the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) is less than 65% by weight based on the total weight of the mixed refrigerant composition, the content of 1,1-difluoroethane (R-152a) may increase, and the thermal stability may decrease. In addition, the content of carbon dioxide (R-744) may increase, and the cooling capacity may decrease. If the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) is more than 95% by weight based on the total weight of the mixed refrigerant composition, the content of 1,1-difluoroethane (R-152a) may decrease, and the cooling capacity may decrease. Within this content range, the thermal stability, cooling capacity, and environmental friendliness of the mixed refrigerant composition can be improved.

[0042] In some embodiments, the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) may be 75% to 90% by weight, 75% to 89% by weight, 75% to 88% by weight, 75% to 87% by weight, or 75% to 85% by weight based on the total weight of the mixed refrigerant composition. Within the above content ranges, the thermal stability and refrigeration capacity of the mixed refrigerant composition can be further improved.

[0043] According to an exemplary embodiment, the content of the 1,1-difluoroethane (R-152a) may be 1 wt% to 30 wt%, 3 wt% to 30 wt%, or 5 wt% to 30 wt% based on the total weight of the mixed refrigerant composition. If the content of the 1,1-difluoroethane (R-152a) is less than 1 wt% based on the total weight of the mixed refrigerant composition, the refrigeration capacity may decrease. If the content of the 1,1-difluoroethane (R-152a) is more than 30 wt% based on the total weight of the mixed refrigerant composition, the global warming potential (GWP) value may increase. This may decrease the environmental compatibility of the mixed refrigerant composition. Within the above range, the cooling capacity of the mixed refrigerant composition may be improved while increasing the environmental compatibility.

[0044] In some embodiments, the content of the 1,1-difluoroethane (R-152a) may be 10% by weight to 30% by weight, 10% by weight to 25% by weight, 13% by weight to 25% by weight, 15% by weight to 25% by weight, 15% by weight to 23% by weight, or 18% by weight to 23% by weight based on the total weight of the mixed refrigerant composition. In the above content range, the environmental compatibility of the mixed refrigerant composition is improved, and the cooling capacity can be further improved, and the latent heat of vaporization of the mixed refrigerant composition can be further increased. This can further improve the refrigeration capacity.

[0045] In some embodiments, the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition may be 6 to 95, 6 to 90, 10 to 85, 10 to 80, or 13 to 80. In the above ranges, the thermal stability, environmental friendliness, and refrigeration capacity of the mixed refrigerant composition can be improved.

[0046] In one embodiment, the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition may be 13 to 60, 13 to 45, 13 to 40, 13 to 35, 13 to 30, 13 to 25, 13 to 20, or 13 to 18. Within the above ranges, the thermal stability, environmental friendliness, and refrigeration capacity of the mixed refrigerant composition can be further improved.

[0047] In some embodiments, the ratio of the content of the 1,1-difluoroethane (R-152a) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition may be 0.5 to 30, 1 to 25, 1 to 20, or 1 to 15. In the above ranges, the cooling capacity of the mixed refrigerant composition can be improved.

[0048] In one embodiment, the ratio of the content of the 1,1-difluoroethane (R-152a) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition may be 1 to 15, 1 to 10, 1 to 7, or 1 to 6. In the above ranges, the cooling capacity of the mixed refrigerant composition can be further improved.

[0049] In some embodiments, the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the 1,1-difluoroethane (R-152a) in the total weight of the mixed refrigerant composition may be 2 to 19, 2 to 18, 2 to 15, 2 to 10, 3 to 10, 3 to 9, or 3 to 6. In the above ranges, the thermal stability and the refrigeration capacity can be improved.

[0050] In one embodiment, the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the 1,1-difluoroethane (R-152a) in the total weight of the mixed refrigerant composition may be 3.5 to 6, 3.5 to 5.5, 3.5 to 5.4, 3.5 to 5, or 3.5 to 4. In the above ranges, the thermal stability and refrigeration capacity of the mixed refrigerant composition can be further improved.

[0051] According to an exemplary embodiment, the boiling point of the mixed refrigerant composition at 1 atm may be -65°C to -30°C, -60°C to -30°C, -55°C to -34°C, or -55°C to -40°C.

[0052] If the boiling point of the mixed refrigerant composition is less than -65°C, the condensation pressure at the condensation temperature of the mixed refrigerant composition may increase, which may increase the energy consumed in the refrigeration cycle and reduce the efficiency of the refrigerant.

[0053] If the boiling point of the mixed refrigerant composition exceeds -30°C, the specific volume of the mixed refrigerant composition at the condensation temperature may increase, which may increase the amount of the mixed refrigerant composition required to improve the refrigeration capacity, and may increase the volume of the air conditioner.

[0054] In some embodiments, the boiling point of the mixed refrigerant composition at 1 atm may be -55°C to -45°C, -53°C to -45°C, or -53°C to -48°C. In the range of the boiling point of the mixed refrigerant composition, the specific volume can be reduced without increasing the condensation pressure. This allows the refrigeration capacity of the refrigerant to be improved while reducing the amount of the mixed refrigerant composition.

[0055] In some embodiments, the critical temperature of the mixed refrigerant composition may be 90° C. to 100° C., 95° C. to 100° C., 97° C. to 100° C., or 97° C. to 99° C. The critical temperature is the maximum temperature at which a particular substance can exist in a liquid state, and if the critical temperature of a refrigerant is low, it may be difficult to liquefy the refrigerant during condensation in a refrigeration cycle.

[0056] Within the critical temperature range, the mixed refrigerant composition does not become a supercritical fluid in the refrigeration cycle, thereby preventing a portion of the mixed refrigerant composition from becoming a supercritical fluid and not liquefying, thereby improving the refrigeration capacity.

[0057] In some embodiments, the critical pressure of the mixed refrigerant composition may be 30 bar to 51 bar, 30 bar to 50 bar, 35 bar to 50 bar, 35 bar to 45 bar, 39 bar to 45 bar, or 40 bar to 45 bar. Critical pressure is the maximum pressure at which a particular substance can exist in a liquid state, and if the critical pressure of a refrigerant is high, it may be difficult to liquefy the refrigerant in a refrigeration cycle.

[0058] Within the critical pressure range, the mixed refrigerant composition can be prevented from becoming a supercritical fluid in the refrigeration cycle, thereby preventing a portion of the mixed refrigerant composition from not liquefying, and improving the refrigeration capacity.

[0059] In some embodiments, the mixed refrigerant composition may have a temperature glide at a pressure of 1.5 bar of 3°C to 29°C, 3°C to 28°C, 8°C to 27°C, 10°C to 26°C, 11°C to 26°C, 11°C to 25°C, 11°C to 20°C, or 15°C to 20°C. In the above temperature gradient range, separation of the composition can be prevented even if the mixed refrigerant leaks. This allows the usage capacity of the mixed refrigerant composition to be improved even when a heat pump of the same volume is used.

[0060] In some embodiments, the mixed refrigerant composition may have a temperature glide at a pressure of 15 bar of 2°C to 23°C, 2°C to 13°C, 4°C to 13°C, 4.5°C to 13°C, 5°C to 13°C, 6.5°C to 13°C, 9°C to 13°C, or 11°C to 13°C. Within the above temperature gradient range, the mixed refrigerant composition can be used in a heat pump without separation of the composition. This can improve the heat transfer efficiency of the refrigerant.

[0061] In some embodiments, the latent heat at -25°C may be 150 kJ / kg to 250 kJ / kg, 180 kJ / kg to 250 kJ / kg, 180 kJ / kg to 230 kJ / kg, 180 kJ / kg to 220 kJ / kg, 190 kJ / kg to 220 kJ / kg, 195 kJ / kg to 220 kJ / kg, 200 kJ / kg to 215 kJ / kg, or 205 kJ / kg to 215 kJ / kg.

[0062] In the above range of latent heat, the mixed refrigerant composition may release or absorb sufficient heat during a phase change, thereby improving the thermal efficiency of the mixed refrigerant composition.

[0063] In some embodiments, the mixed refrigerant composition may have a global warming potential (GWP) of 1-40, 1-30, 5-30, 10-30, 10-28, 15-28, or 19-28.

[0064] Global warming potential (GWP) is a value calculated using carbon dioxide (CO2) as the reference substance to express the effect of a given chemical substance on global warming over a certain period of time (e.g., 100 years) when 1 kg of that substance is released into the Earth's troposphere.

[0065] Within this range of global warming potential, the cooling capacity can be improved while suppressing environmental pollution caused by the use and disposal of the mixed refrigerant composition.

[0066] In some embodiments, the mixed refrigerant composition may have an Ozone Depletion Potential (ODP) of zero.

[0067] The ozone depletion potential (ODP) is a value calculated by converting the degree to which a given chemical substance affects ozone depletion, assuming that the impact of trichlorofluoromethane (CFC-11) on ozone depletion is 1.

[0068] By having an ozone depletion potential (ODP) of 0, environmental pollution caused by the use and disposal of the mixed refrigerant composition can be suppressed.

[0069] In some embodiments, the mixed refrigerant composition may be non-flammable. For example, the mixed refrigerant composition may be rated A2L in the refrigerant safety group classification of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). This can improve the operation and stability of the heat pump in the event of leakage.

[0070] According to an exemplary embodiment, a heat pump includes the mixed refrigerant composition, which provides the heat pump with improved environmental friendliness, stability, and improved refrigeration performance.

[0071] The heat pump may include a compressor, a condenser, an expansion valve, and an evaporator. The compressor may compress the mixed refrigerant composition to a high temperature and high pressure state, and the expansion valve may expand the mixed refrigerant composition to a low temperature and low pressure state.

[0072] For example, the mixed refrigerant composition can absorb or release heat while circulating through the compressor, condenser, expansion valve, and evaporator in the heat pump. The mixed refrigerant composition can be maintained in a high-temperature and high-pressure gaseous state in the compressor. The mixed refrigerant composition can be liquefied to a liquid state by releasing heat in the condenser. The mixed refrigerant composition can be maintained in a low-temperature and low-pressure liquid state or a mixture of liquid and gas in the expansion valve. The mixed refrigerant composition can be evaporated to a gaseous state by absorbing heat in the evaporator.

[0073] In some embodiments, the heat pump can include oil, such as paraffin, naphthene, aromatic hydrocarbon, polyester (POE), polyol ester, mineral oil, alkylbenzene (AB), polyalkylene glycol (PAG), polyvinyl ether (PVE), etc., to prevent friction and wear in the heat pump.

[0074] In some embodiments, the heat pump may have a coefficient of performance (COP) of 1 to 10. The coefficient of performance (COP) refers to the ratio of the amount of heat effectively obtained to the amount of work input when operating a heat pump.

[0075] Using the above-mentioned refrigerants, a highly efficient heat pump having a coefficient of performance in the above-mentioned range can be provided.

[0076] Below, preferred examples are presented to aid in understanding the present invention. However, these examples are merely illustrative of the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications to the examples are possible within the scope of the scope and technical spirit of the present invention, and it is natural that such changes and modifications also fall within the scope of the appended claims.

[0077] Examples and Comparative Examples (1) Mixed refrigerant composition A mixed refrigerant composition having the components and contents (wt %) shown in Table 1 below was prepared. The boiling point, critical temperature, critical pressure, temperature gradient at 1.5 bar and 15 bar, and latent heat at -25°C of the prepared mixed refrigerant composition were measured. The boiling point, critical temperature, critical pressure, temperature gradient at 1.5 bar and 15 bar, and latent heat at -25°C of the measured mixed refrigerant composition are shown in Table 1 below. The boiling point, critical temperature, critical pressure, temperature gradient and latent heat of the mixed refrigerant composition were measured using REFPROP (Ver 10, NIST).

[0078] [Table 1]

[0079] The specific components shown in Table 1 are as follows: R-744: Carbon dioxide R-1234yf: 2,3,3,3-tetrafluoropropene R-152a: 1,1-difluoroethane

[0080] Experimental Example (1) Calculation of GWP Based on the global warming potential (GWP) of R-744, R-1234yf, and R-152a contained in the mixed refrigerant composition according to the examples set forth in the Intergovernmental Panel on Climate Change (IPCC), the global warming potential (GWP) of the mixed refrigerant composition was calculated by arithmetically averaging the respective weight ratios of R-744, R-1234yf, and R-152a. The IPCC Global Warming Potential (GWP) is based on a 100-year GWP. The calculated global warming potential (GWP) is shown in Table 2 below.

[0081] [Table 2]

[0082] (2) Cooling evaluation 1 and 2 are schematic diagrams illustrating mixed refrigerant flow for heat exchange in cooling and heating modes, respectively, of a heat exchanger according to an exemplary embodiment.

[0083] The direction of the arrows in FIG. 1 and FIG. 2 is intended to indicate the flow of the mixed refrigerant.

[0084] Referring to FIG. 1, in cooling mode, the mixed refrigerant is compressed by the compressor, sequentially bypasses the internal condenser and the expansion valve (heating), releases heat in the external condenser, expands in the expansion valve (cooling), and reabsorbs heat through the evaporator.

[0085] Referring to FIG. 2, in heating mode, the mixed refrigerant is compressed by the compressor, releases heat in the internal condenser, expands through the expansion valve (heating), absorbs heat in the external condenser, and then further absorbs heat through the cooler.

[0086] Using the combinations of refrigerants of Examples 1 to 21 and Comparative Examples 1 to 6, cooling evaluations and heating evaluations were performed using the above-mentioned heat exchanger at different outside air temperatures.

[0087] The cooling evaluation was performed by setting the outdoor temperature at 45° C., and the heating evaluation was performed by setting the outdoor temperature at −7° C. and −20° C. The conditions for the cooling evaluation and heating evaluation according to the above-mentioned examples and comparative examples are shown in Table 3 below.

[0088] Specifically, the outside air temperature (°C), the refrigerant temperature at the condenser outlet, the degree of refrigerant subcooling at the condenser outlet, the refrigerant temperature at the evaporator outlet, and the degree of refrigerant superheat at the evaporator outlet are summarized in Table 3 below.

[0089] [Table 3A] [Table 3B]

[0090] The cooling and heating analyses of the examples and comparative examples in Table 3 were verified using Cycle-D (provided by NIST), an OD analysis program. Specifically, the volumetric capacity, the temperature at the compressor outlet, and the pressure were evaluated by the cooling and heating analyses. The volumetric capacity was calculated according to the following formula 1.

[0091]

number

[0092] The evaluation results are shown in Tables 4 to 6 below.

[0093] [Table 4]

[0094] [Table 5]

[0095] [Table 6]

[0096] Referring to Table 4, in the embodiment within the scope of the present disclosure, the volumetric capacity in the cooling evaluation (outdoor temperature: 45° C.) is 2618.9 kJ / m 3 The compressor outlet temperature was 88.4°C or lower.

[0097] Volumetric capacity is the amount of energy that a refrigerant can contain per unit volume. The larger the volumetric capacity, the greater the amount of energy that the same volume of refrigerant can move, resulting in a refrigerant with good air conditioning performance.

[0098] Compared with the Examples, Comparative Example 1 in which R-1234yf was used alone had a reduced volumetric capacity.

[0099] In the case of Comparative Example 3 and Comparative Example 4, in which R-152a was contained in an amount of 30% by weight or more based on the total weight of the mixed refrigerant composition, the cooling volume capacity showed a tendency to converge, while the compressor outlet pressure and compressor outlet temperature showed a tendency to increase.

[0100] Referring to the comparative example, as the content of R-744 increased, the compressor outlet pressure and the compressor outlet temperature tended to increase.

[0101] Referring to Table 5, in the embodiment within the scope of the present disclosure, the volumetric capacity at the heating rating (outdoor temperature: -7°C) is 1369.8 kJ / m 3 The compressor outlet temperature was 79.9°C or lower.

[0102] Compared with the Examples, Comparative Example 1 in which R-1234yf was used alone had a reduced volumetric capacity.

[0103] In the case of Comparative Example 3 and Comparative Example 4, in which R-152a was contained in an amount of 30% by weight or more based on the total weight of the mixed refrigerant composition, the heating volume capacity showed a tendency to converge, while the compressor outlet pressure and compressor outlet temperature showed a tendency to increase.

[0104] Referring to the comparative example, as the content of R-744 increased, the compressor outlet pressure and the compressor outlet temperature tended to increase.

[0105] Referring to Table 6, in the embodiment within the scope of the present disclosure, the volumetric capacity in the heating rating (outdoor temperature: -20°C) is 1060.3 kJ / m 3 The compressor outlet temperature was 64.2°C or lower.

[0106] Compared with the Examples, Comparative Example 1 in which R-1234yf was used alone had a reduced volumetric capacity.

[0107] In the case of Comparative Example 3 and Comparative Example 4, in which R-152a was contained in an amount of 30% by weight or more based on the total weight of the mixed refrigerant composition, the heating volume capacity showed a tendency to converge, while the compressor outlet pressure and compressor outlet temperature showed a tendency to increase.

[0108] Referring to the comparative example, as the content of R-744 increased, the compressor outlet pressure and the compressor outlet temperature tended to increase.

[0109] As can be seen from the results in Tables 5 to 7, it is preferable to use a mixed refrigerant containing all of R-744, R-1234yf, and R-152a, rather than using R-1234yf alone as a refrigerant. It is also preferable to limit the maximum content of R-744 to 10% by weight based on the total weight of the mixed refrigerant composition.

[0110] In addition, taking into consideration that the GWP increases when the content of R-152a increases, it is preferable to limit the maximum content of R-152a to an amount of 30 wt.% based on the total weight of the mixed refrigerant composition.

Claims

1. Carbon dioxide (R-744), 2,3,3,3-tetrafluoropropene (R-1234yf), and 1,1-difluoroethane (R-152a), The content of the carbon dioxide (R-744) is 1% by weight to 10% by weight based on the total weight of the mixed refrigerant composition, The content of the 2,3,3,3-tetrafluoropropene (R-1234yf) is 65% by weight to 95% by weight based on the total weight of the mixed refrigerant composition, The content of the 1,1-difluoroethane (R-152a) is 1% by weight to 30% by weight based on the total weight of the mixed refrigerant composition, A mixed refrigerant composition having a boiling point at 1 atm of -65°C to -30°C.

2. The mixed refrigerant composition according to claim 1, which is composed of the carbon dioxide (R-744), the 2,3,3,3-tetrafluoropropene (R-1234yf), and the 1,1-difluoroethane (R-152a).

3. The mixed refrigerant composition according to claim 1, wherein the content of 1,1-difluoroethane (R-152a) is 13% by weight to 25% by weight based on the total weight of the mixed refrigerant composition.

4. The mixed refrigerant composition according to claim 1, wherein the content of 1,1-difluoroethane (R-152a) is 18% by weight to 23% by weight based on the total weight of the mixed refrigerant composition.

5. The mixed refrigerant composition according to claim 1, wherein the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition is 6 to 95.

6. The mixed refrigerant composition according to claim 1, wherein the ratio of the content of the 1,1-difluoroethane (R-152a) to the content of the carbon dioxide (R-744) in the total weight of the mixed refrigerant composition is 0.5 to 30.

7. The mixed refrigerant composition according to claim 1, wherein the ratio of the content of the 2,3,3,3-tetrafluoropropene (R-1234yf) to the content of the 1,1-difluoroethane (R-152a) in the total weight of the mixed refrigerant composition is 2 to 19.

8. The mixed refrigerant composition according to claim 1, wherein the critical temperature of the mixed refrigerant composition is 90°C to 100°C.

9. 2. The mixed refrigerant composition according to claim 1, wherein the critical pressure of the mixed refrigerant composition is 30 bar to 51 bar.

10. 2. The mixed refrigerant composition of claim 1, wherein the mixed refrigerant composition has a temperature glide of 3° C. to 29° C. at a pressure of 1.5 bar.

11. 2. The mixed refrigerant composition of claim 1, wherein the mixed refrigerant composition has a temperature glide of 2°C to 23°C at a pressure of 15 bar.

12. The mixed refrigerant composition according to claim 1, wherein the latent heat of the mixed refrigerant composition at -25°C is 150 kJ / kg to 250 kJ / kg.

13. The mixed refrigerant composition according to claim 1, wherein the mixed refrigerant composition has a global warming potential (GWP) of 1 to 40.

14. A heat pump comprising the mixed refrigerant composition of claim 1.

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