Compositions of HFO-1234YF, HFC-152A, and HFC-32, and systems for using the same

Abstract

An environmentally friendly refrigerant blend utilizing refrigerants including 2,3,3,3-tetrafluoropropene (HFO-1234yf), difluoromethane (HFC-32), and 1,1-difluoroethane (HFC-152a). The blend has low GWP, toxicity, and flammability with low temperature glide for use in hybrid, mild hybrid, plug-in hybrid, or all-electric vehicles for passenger compartment thermal management (heat transfer from one part of the vehicle to another) to provide air conditioning (A / C) or heating to the passenger compartment.

Description

[Technical field]

[0001] The present invention is directed to compositions comprising HFO-1234yf, HFC-152a, and HFC-32, and their use as refrigerants in air conditioning and heat pump systems. [Background technology]

[0002] The automotive industry is experiencing an architecture platform revitalization from using an internal combustion engine (ICE) for propulsion to using electric motors for propulsion. This platform revitalization may significantly limit the size of the internal combustion engine (ICE) in hybrid, plug-in hybrid vehicles, or eliminate the ICE entirely in pure electric vehicles. Some vehicles still retain the ICE and are known as hybrid electric vehicles (HEVs) or plug-in hybrids electric vehicles (PHEVs) or mild hybrids electric vehicles (MHEVs). Vehicles that are fully electric and have no ICE are called fully electric vehicles (EVs), including battery electric vehicles (BEVs). All HEVs, PHEVs, MHEVs, and EVs use at least one electric motor. This electric motor provides some form of propulsion to the vehicle that is typically provided by the internal combustion engine (ICE) found in gasoline / diesel vehicles.

[0003] In electric vehicles, the ICE is usually reduced in size (HEV, PHEV, or MHEV) or eliminated (EV) to reduce the vehicle weight and thereby increase the electric drive cycles. The primary function of the ICE is to provide propulsion for the vehicle, but also provides heat to the passenger compartment as a secondary function. Heating is usually required when ambient conditions are below 10°C. In non-electric vehicles, there is excess heat from the ICE, which can be captured and used to heat the passenger compartment. It should be noted that the ICE can function well down to temperatures as low as -30°C, although it may take some time (several minutes) to heat up and generate heat. Thus, in electric vehicles, the reduction or elimination of the ICE size creates a demand for effective heating of the passenger compartment. In current EVs without an ICE, positive temperature coefficient (PTC) heaters are used. The use of a heat pump for cooling and heating can replace the PTC heater along with the air conditioning system, allowing for more efficient cooling and heating.

[0004] Due to environmental pressures, R-134a, hydrofluorocarbons or HFCs have been phased out for automotive air conditioning in favor of lower GWP refrigerants with a global warming potential (GWP) of less than 150. HFO-1234yf, a hydrofluoroolefin, meets the low GWP requirements (GWP=4 per Papadimitriou, GWP<1 per AR5), but has a lower refrigeration capacity compared to R-134a and cannot fully meet the heating needs at low (-10°C) to very low (-30°C) ambient temperatures in current system designs. Refrigerant blends commonly used in stationary refrigerant applications are another option for automotive heat pumps. Examples of compositions containing HFO-1234yf are disclosed in WO 2007 / 126414. These disclosures are incorporated herein by reference.

[0005] Similarly, stationary residential and commercial structural heating and cooling also suffers from a lack of suitable low GWP refrigerants to replace the older high GWP refrigerants currently in use. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, low GWP heat pump type fluids are needed to meet the ever-increasing needs for thermal management that can provide both cooling and heating in hybrid, mild hybrid, plug-in hybrid and electric vehicles, electrified mass transportation, and residential and commercial structures. [Means for solving the problem]

[0007] The present invention relates to compositions of environmentally friendly refrigerant blends, having low GWP (GWP below 100), low toxicity (Class A by ANSI / ASHRAE Standard 34 or ISO Standard 817), low flammability (Class 2 or Class 2L by ASHRAE 34 or ISO 817), with low temperature glides for hybrid, mild hybrid, plug-in hybrid, or fully electric vehicles for complete vehicle thermal management (transferring heat from one part of the vehicle to another). The thermal management system can operate to provide cooling and / or heating for the power electronics, battery, motor, and provide air conditioning (A / C) or heating for the passenger compartment. These refrigerants can also be used in mass transit mobile applications that benefit from a heat pump type system that allows both heating and cooling for the battery, motor, and passenger compartment areas. Mass transit mobile applications can include, but are not limited to, transportation vehicles such as ambulances, buses, shuttles, and trains.

[0008] In one aspect of the invention, the refrigerant composition comprises a mixture of HFO-1234yf, HFC-152a, and HFC-32. The composition of the invention exhibits low temperature glide over the operating conditions of the vehicle's thermal management system. It is preferable to have low temperature glide fluid or no glide due to the way the automobile is repaired or maintained. Currently, during the repair or maintenance process of the A / C of a vehicle, the refrigerant is handled through a specific automobile maintenance machine. This machine recovers the refrigerant, recycles the refrigerant to an intermittent quality level to remove gross contaminants, and then recharges the vehicle with the refrigerant after the repair or maintenance is completed. These machines are called R / R / R machines because they recover, recycle, and recharge the refrigerant. This on-site recovery, recycling, and recharging of the refrigerant during the maintenance or repair of the vehicle is possible because of the single compound refrigerant currently used, HFO-1234yf. Current automotive service machines typically cannot handle refrigerant blends that may fractionate during use and in some cases exhibit preferential leakage of the lowest boiling component(s). Thus, the refrigerant removed from the system during service may not yield the same percentage of components as the original blend charged. Because the refrigerants are handled "on-site" at the vehicle repair shop, there is no opportunity to reconstitute the blended refrigerant to its original compositional concentrations as refrigerant recyclers do. Refrigerants with higher temperature glide may require "reconstitution" to the original formulation or loss of cycle performance may occur. Thus, a need exists for refrigerants with lower temperature glide for automotive applications. Because heat pump fluids are handled in the same manner as air conditioning fluids, the requirement for low temperature glide also applies to heat pump type fluids. This is because they are handled and / or serviced in the same manner as traditional air conditioning fluids. Furthermore, current heat exchanger designs are based on the use of single compound refrigerants. New refrigerants with significant temperature glide may require a complete redesign of the heat exchangers and other system components to maintain the overall system performance of current systems utilizing single component fluids.

[0009] While HFO-1234yf can be used as an air conditioning refrigerant, it has limited ability to perform as a heat pump type fluid, i.e., capable of providing the required capacity in both cooling and heating modes. Thus, the refrigerants described herein uniquely provide improved capacity over HFO-1234yf in the heating operating range and / or extend the capacity of the lower heating range to evaporator temperatures of -30°C, provide equivalent or improved efficiency (COP), have a lower GWP, low to mild flammability, but also exhibit a unique low temperature glide. Thus, these refrigerants are most useful in electrified vehicle applications, particularly HEVs, PHEVs, MHEVs, EVs, and mass transit vehicles that require these properties in the lower heating range. It should be noted that the heat pump fluid must perform well in the air conditioning cycle, i.e., up to 40°C refrigerant average condensing temperature, and desirably provide equivalent or increased capacity to HFO-1234yf. Thus, the refrigerant blends described herein perform particularly well over a temperature range of about -30°C to +40°C and can provide heating or cooling depending on the cycle being used in the heat pump system.

[0010] The inventors have discovered that refrigerant blends that provide greater cooling capacity than HFO-1234yf alone in heating mode, a COP equal to or greater than the COP of HFO-1234yf alone, and have an average temperature glide less than 4 K, preferably less than 3 K, or even less than 2.5 K, are non-toxic and classified by ASHRAE as Class 2 or 2L flammable.

[0011] The present invention includes the following aspects and embodiments. In one embodiment, disclosed herein are compositions useful as refrigerants and heat transfer fluids. The compositions disclosed herein include 2,3,3,3-tetrafluoropropene (HFO-1234yf), difluoromethane (HFC-32), and 1,1-difluoroethane (HFC-152a).

[0012] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition comprising a refrigerant blend comprising 66 to 80 weight percent HFO-1234yf, 1 to 10 weight percent HFC-32, and 10 to 24 weight percent HFC-152a.

[0013] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of 69 to 80 weight percent HFO-1234yf, 5 to 8 weight percent HFC-32, and 12 to 24 weight percent HFC-152a.

[0014] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of 70 to 78 weight percent HFO-1234yf, 6 to 8 weight percent HFC-32, and 14 to 24 weight percent HFC-152a.

[0015] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of 70 to 78 weight percent HFO-1234yf, 6 to 7.5 weight percent HFC-32, and 14 to 24 weight percent HFC-152a.

[0016] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of 72 to 78 weight percent HFO-1234yf, 6 to 7.5 weight percent HFC-32, and 14 to 20 weight percent HFC-152a.

[0017] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of 74 to 78 weight percent HFO-1234yf, 6 to 7.5 weight percent HFC-32, and 14 to 18 weight percent HFC-152a.

[0018] According to any of the foregoing embodiments, also disclosed herein is a composition, the refrigerant blend comprising: about 70 weight percent HFO-1234yf, 6 weight percent HFC-32, and about 24 weight percent HFC-152a; about 74 weight percent HFO-1234yf, about 7 weight percent HFC-32, and about 19 weight percent HFC-152a; about 77 weight percent HFO-1234yf, about 3 weight percent HFC-32, and about 20 weight percent HFC-152a; about 78 weight percent HFO-1234yf, 7.5 weight percent HFC-32, and about 14.5 weight percent HFC-152a; about 78 weight percent HFO-1234yf, 6 weight percent HFC-32, and about 16 weight percent HFC-152a; about 79 weight percent HFO-1234yf, 3 weight percent HFC-32, and about 18 weight percent HFC-152a; about 80 weight percent HFO-1234yf, 4 weight percent HFC-32, and about 16 weight percent HFC-152a; about 70 weight percent HFO-1234yf, about 8 weight percent HFC-32, and about 22 weight percent HFC-152a; or consists essentially of about 67 weight percent HFO-1234yf, about 10 weight percent HFC-32, and about 23 weight percent HFC-152.

[0019] Also disclosed herein are compositions, according to any of the foregoing embodiments, wherein the refrigerant blend provides an average temperature glide of from about 0.1 K to less than about 4 K.

[0020] Also disclosed herein are compositions, according to any of the foregoing embodiments, wherein the refrigerant blend provides an average temperature glide of from about 0.1 K to less than about 3 K.

[0021] Also disclosed herein are compositions, according to any of the foregoing embodiments, wherein the refrigerant blend provides an average temperature glide of from about 0.1 K to less than about 2.5 K.

[0022] Also disclosed herein are compositions, according to any of the foregoing embodiments, wherein the refrigerant blend provides an average temperature glide of from about 0.1 K to less than about 2.0 K.

[0023] Also disclosed herein is a composition, according to any of the foregoing embodiments, wherein the refrigerant blend has a GWP of about 100 or less based on the AR5.

[0024] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of, or has a GWP of less than about 75 based on the AR5.

[0025] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of, or has a GWP of less than about 50 based on the AR5.

[0026] According to any of the above embodiments, the present disclosure further includes at least one additional compound, the additional compound being: a) at least one compound selected from the group consisting of HCFC-244bb, HFC-245cb, HFC-254eb, CFC-12, HCFC-124, 3,3,3-trifluoropropyne, HCC-1140, HFC-1225ye, HFO-1225zc, HFC-134a, HFO-1243zf, and HCFO-1131; or b) comprising at least one compound selected from the group consisting of HFC-23, HCFC-31, HFC-41, HFC-143a, HCFC-22, HCC-40, HFC-161, HFO-1141, HCO-1140, HCFC-151a, HCC-150a, HCC-160, HCFO-1130a, HCFC-141b, HFC-143a, HCFO-1122, and HCFC-142b; or c) including a combination of a) and b), Also disclosed herein are compositions wherein the total amount of additional compounds comprises greater than 0 and less than 1 weight percent.

[0027] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition wherein the additional compound comprises at least one of HFC-161, HFO-1141, HCO-1140, HCFC-151a, HCC-150a, or HCC-160, or a combination thereof.

[0028] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend consists essentially of where the additional compounds include HFC-143a, HCC-40, HFC-161, and HCFC-151a.

[0029] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition wherein the additional compound includes HFO-1243zf, HFC-143a, HCC-40, HFC-161, and HCFC-151a.

[0030] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition, wherein the additional composition comprises HFO-1243zf, HCC-40, HFC-161.

[0031] Also disclosed herein, according to any of the foregoing embodiments, is a composition wherein the refrigerant blend has a burning velocity of 10 cm / s or less when measured according to the ISO 817 vertical tube method.

[0032] Also disclosed herein, according to any of the foregoing embodiments, is a composition wherein the refrigerant blend is classified as 2L for flammability as defined in ANSI / ASHRAE Standard 34.

[0033] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the refrigerant blend has an LFL of less than 10 volume percent as measured according to ASTM-E681.

[0034] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition further comprising a lubricant.

[0035] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition wherein the lubricant comprises at least one selected from the group consisting of polyalkylene glycols, polyol esters, poly-α-olefins, and polyvinyl ethers.

[0036] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition, wherein the polyol ester lubricant is obtained by reacting a carboxylic acid with a polyol containing a neopentyl backbone selected from the group consisting of neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and mixtures thereof.

[0037] Also disclosed herein, according to any of the preceding embodiments, is a composition wherein the carboxylic acid has 2-18 carbon atoms.

[0038] According to any of the above embodiments, the lubricant has a viscosity of 10 10 Also disclosed herein are compositions having a volume resistivity greater than Ω-m.

[0039] Also disclosed herein, according to any of the foregoing embodiments, is a composition wherein the lubricant has a surface tension of about 0.02 N / m to 0.04 N / m at 20° C.

[0040] Also disclosed herein, according to any of the foregoing embodiments, is a composition wherein the lubricant has a kinematic viscosity at 40° C. of about 20 cSt to about 500 cSt.

[0041] Also disclosed herein is a composition, according to any of the foregoing embodiments, wherein the lubricant has a breakdown voltage of at least 25 kV.

[0042] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition wherein the lubricant has a hydroxyl value of at most 0.1 mg KOH / g.

[0043] Also disclosed herein, according to any of the preceding embodiments, is a composition further comprising 0.1 to 200 ppm by weight of water.

[0044] Also disclosed herein are compositions, according to any of the preceding embodiments, further comprising about 10 ppm by volume to about 0.35 percent by volume of oxygen.

[0045] Also disclosed herein are compositions, according to any of the foregoing embodiments, further comprising about 100 ppm by volume to about 1.5 percent by volume air.

[0046] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition further comprising a stabilizer.

[0047] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the stabilizer is selected from the group consisting of nitromethane, ascorbic acid, terephthalic acid, azoles, phenolic compounds, cyclic monoterpenes, terpenes, phosphites, phosphates, phosphonates, thiols, and lactones.

[0048] According to any of the preceding embodiments, a composition is also disclosed herein, wherein the stabilizer is selected from tolutriazole, benzotriazole, tocopherol, hydroquinone, t-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, fluorinated epoxides, n-butyl glycidyl ether, hexanediol diglycidyl ether, allyl glycidyl ether, butylphenyl glycidyl ether, d-limonene, α-terpinene, β-terpinene, α-pinene, β-pinene, or butylated hydroxytoluene.

[0049] Further disclosed herein is a composition, in accordance with any of the preceding embodiments, wherein the stabilizer is present in an amount of about 0.001 to 1.0 weight percent based on the weight of the refrigerant.

[0050] Also disclosed herein, in accordance with any of the preceding embodiments, is a composition further comprising at least one oligomer.

[0051] Also disclosed herein, according to any of the preceding embodiments, is a composition wherein the at least one tracer is present in an amount of about 10 ppm to about 1000 ppm by weight.

[0052] Also disclosed herein, in accordance with any of the foregoing embodiments, is a composition wherein the at least one tracer is selected from the group consisting of hydrofluorocarbons, hydrofluoroolefins, hydrochlorocarbons, hydrochloroolefins, hydrochlorofluorocarbons, hydrochlorofluoroolefins, hydrochlorocarbons, hydrochloroolefins, chlorofluorocarbons, chlorofluoroolefins, hydrocarbons, perfluorocarbons, perfluoroolefins, and combinations thereof.

[0053] According to any of the foregoing embodiments, the at least one tracer may be selected from the group consisting of HFC-23, HCFC-31, HFC-41, HFC-161, HFC-143a, HFC-134a, HFC-125, HFC-236fa, HFC-236ea, HFC-245cb, HFC-245fa, HFC-254eb, HFC-263fb, HFC-272ca, HFC-281ea, HFC-281fa, HFC-329p, HFC-329mmz, HFC-338mf, HFC-338pcc, HCFC-12, HCFC-11, HCFC-114, CFC-114a, HCFC-22, HCFC-123, HFC-125 ... Also disclosed herein are compositions selected from the group consisting of CFC-124, HCFC-124a, HCFC-141b, HCFC-142b, HCFC-151a, HCFC-244bb, HCC-40, HFO-1141, HCFO-1130, HCFO-1130a, HCFO-1131, HCFO-1122, HFO-1123, HFO-1234ye, HFO-1243zf, HFO-1225ye, HFO-1225zc, PFC-116, PFC-C216, PFC-218, PFC-C318, PFC-1216, PFC-31-10mc, PFC-31-10my, and combinations thereof.

[0054] In another embodiment, disclosed herein is a refrigerant storage vessel containing a composition according to any of the previous embodiments, wherein the refrigerant comprises a gas phase and a liquid phase.

[0055] In another embodiment, also disclosed herein is a system for heating and cooling a passenger compartment of an electric vehicle, the system including an evaporator, a compressor, a condenser, and an expansion device, each operatively connected to perform a vapor compression cycle, wherein a refrigerant composition of any of the preceding embodiments is circulated through each of the evaporator, the compressor, the condenser, and the expansion device.

[0056] Also disclosed herein is a heating or cooling system having a temperature glide of less than 4.0K, 3.0K, 2.5K, or 2.0K, according to any of the aforementioned embodiments.

[0057] Also disclosed herein is a cooling and heating system, according to any of the aforementioned embodiments, wherein the system does not include a PTC heater.

[0058] Also disclosed herein, in accordance with any of the foregoing embodiments, is a heating or cooling system, wherein the system is not a reversible cooling loop.

[0059] Also disclosed herein, in accordance with any of the aforementioned embodiments, is a heating or cooling system, the system further comprising a reheater operably connected between the compressor and the condenser.

[0060] Also disclosed herein, in accordance with any of the preceding embodiments, is a method of replacing HFO-1234yf in heating and cooling systems contained within an electric vehicle, comprising providing any of the preceding compositions to the heating and cooling system as a heat transfer fluid.

[0061] According to any of the foregoing embodiments, a method for replacing HFO-1234yf, wherein the refrigerant blend produces a volumetric capacity that is at least 7%, or 10%, or 15%, or even 20% higher than that of HFO-1234yf alone when operating under the same heating conditions, is also disclosed herein.

[0062] According to any of the foregoing embodiments, a method for replacing HFO-1234yf, wherein the refrigerant blend produces a coefficient of performance (COP) that is equal to or greater than that of HFO-1234yf alone when operating under the same conditions, is also disclosed herein.

[0063] In another embodiment, a method for servicing the heating and cooling system of an electric vehicle is also disclosed herein, which includes the steps of removing all of the used refrigerant from the system and filling the system with any of the foregoing compositions.

[0064] In another embodiment, disclosed herein is the use of any of the foregoing compositions as a heat transfer fluid in a system for heating and cooling the passenger compartment of an electric vehicle.

[0065] In another embodiment, disclosed herein is the use of a composition comprising a refrigerant blend, 78 weight percent HFO-1234yf, 8 weight percent HFC-32, and 14 weight percent HFC-152a; or 72 weight percent HFO-1234yf, 8 weight percent HFC-32, and 20 weight percent HFC-152a which is essentially used as a heat transfer fluid in a system for heating and cooling the passenger compartment of an electric vehicle.

[0066] In another embodiment, a method for reducing the temperature glide in a heat exchanger operating with a refrigerant blend consisting essentially of HFC-32 and HFO-1234yf, which includes adding HFC-152a to the refrigerant blend composition, is also disclosed herein.

[0067] According to any of the foregoing embodiments, disclosed herein is a method for reducing temperature glide, wherein HFC-152a is added in an amount of about 10 to 24 weight percent based on the weight percent of the total refrigerant blend composition.

[0068] According to any of the aforementioned embodiments, disclosed herein is a method of reducing temperature glide, wherein the temperature glide in a heat exchanger is reduced to less than 3 K.

[0069] The various aspects and embodiments of the invention can be used alone or in combination with each other. Other features and advantages of the present invention will be apparent from the following more detailed description of preferred embodiments, which illustrate, by way of example, the principles of the invention. [Brief description of the drawings]

[0070] [Figure 1] FIG. 1 illustrates a reversible cooling or heating loop system, according to one embodiment. [Diagram 2] FIG. 1 illustrates a reversible cooling or heating loop system, according to one embodiment. [Diagram 3] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. [Figure 4] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. [Diagram 5] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. [Figure 6] A contour plot of temperature glide is used to demonstrate the reduction in glide of an embodiment of the present invention. [Figure 7] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. [Figure 8] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. [Figure 9] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. [Figure 10] FIG. 1 illustrates a reversible cooling or heating system, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0071] definition As used herein, the term heat transfer composition or heat transfer fluid means a composition used to transport heat from a heat source to a heat sink.

[0072] A heat source is defined as any space, location, thing or object where it is desirable to add, transfer, move or remove heat. An example of a heat source in this embodiment is the vehicle passenger compartment of a vehicle requiring air conditioning.

[0073] A heat sink is defined as any space, place, thing or object that can absorb heat. An example of a heat sink in this embodiment is a vehicle passenger compartment that requires heating.

[0074] A heat transfer system is a system (or device) used to produce a heating or cooling effect at a specific location. The heat transfer system of the present invention refers to a reversible heating or cooling system that provides heating or cooling for the passenger compartment of an automobile. This system is sometimes called a heat pump system and may be a reversible heating system or a reversible cooling system, or simply a heating and cooling system.

[0075] The heat transfer fluid includes at least one refrigerant and at least one member selected from the group consisting of lubricants, stabilizers, tracers, UV dyes, and flame suppressants.

[0076] Volumetric capacity is the amount of heat absorbed or rejected divided by the theoretical compressor displacement. The heat removed or absorbed is the enthalpy difference across the heat exchanger multiplied by the refrigerant mass flow rate. Theoretical compressor displacement is the refrigerant mass flow rate divided by the density of the gas entering the compressor (i.e., compressor suction density). More simply, volumetric capacity is the suction density multiplied by the heat exchanger enthalpy difference. Higher volumetric capacity allows the use of smaller compressors for the same heat load. In this specification, cooling capacity refers to the volumetric capacity in cooling mode and heating capacity refers to the volumetric capacity in heating mode.

[0077] The Coefficient of Performance (COP) is the amount of heat absorbed or removed divided by the energy input required to run the cycle (approximated by compressor output). COP is specific to the operating mode of the heat pump, hence the COP for heating or COP for cooling. COP is directly related to the Energy Efficiency Ratio (EER).

[0078] Subcooling refers to lowering the temperature of a liquid below its saturation point at a given pressure. The liquid saturation point is the temperature at which vapor completely condenses into a liquid. Cooling a liquid below its saturation temperature (or boiling point temperature) can increase the net refrigeration effect. Subcooling thereby increases the refrigeration capacity and energy efficiency of the system. The amount of subcooling is the amount of cooling below the saturation temperature (in degrees).

[0079] Superheating refers to raising the temperature of a vapor above its saturation point at a given pressure. The vapor saturation point is the temperature at which a liquid completely evaporates into a vapor. Superheating continues to heat the vapor to a hotter vapor at a given pressure. Heating the vapor above the saturation temperature (or dew point temperature) can increase the net refrigeration effect. Superheating thereby increases the refrigeration capacity and energy efficiency of the system when superheating occurs in the evaporator. Superheating the suction line does not increase the net refrigeration effect and may decrease efficiency and capacity. Superheat is the amount of heating above the saturation temperature (in degrees).

[0080] Temperature glide (sometimes simply called "glide") is the absolute value of the difference between the start and end temperatures of the phase change process by the refrigerant in the compressor of a refrigeration system, excluding any subcooling or superheating. In the case of an evaporator, the glide is the temperature difference between the dew point and the evaporator inlet. Glide can be used to describe the condensation or evaporation of near-azeotropic or non-azeotropic compositions. When referring to the temperature glide of an air conditioning or heat pump system, it is common to provide an average temperature glide, which is the average of the temperature glide in the evaporator and the temperature glide of the condenser. Glide is applicable to blended refrigerants, i.e., refrigerants composed of at least two components.

[0081] Low glide herein is defined as an average glide of less than 4 K over the operating range of interest, more preferably, low glide is less than 3 K over the operating range of interest, more preferably, less than 2.5 K over the operating range of interest, or most preferably, less than 2.0 K over the operating range of interest under heated conditions (e.g., glide in the range from greater than 0 K to less than about 2.0 K).

[0082] An azeotropic composition is a constant-boiling mixture of two or more substances that behaves as a single substance under given conditions of pressure and temperature. One way to identify an azeotropic composition is that the vapor produced by partial evaporation or distillation of a liquid has the same composition as the liquid that was evaporated or distilled, i.e., the mixed distillate / reflux does not change composition. Constant-boiling compositions are characterized as azeotropes because they exhibit either a maximum or minimum boiling point when compared to non-azeotropic mixtures of the same compounds. In operation, within an air conditioning or heating system, assuming constant temperature and pressure, azeotropic compositions do not fractionate. Furthermore, azeotropic compositions do not fractionate upon leakage from an air conditioning or heating system.

[0083] A near azeotropic composition (also commonly referred to as an "azeotrope-like composition") is a substantially constant boiling liquid mixture of two or more substances that essentially behaves as a single substance. One way to characterize a near azeotropic composition is that the vapor produced by partial evaporation or distillation of a liquid has substantially the same composition as the liquid that was evaporated or distilled (i.e., the mixed distillate / reflux without substantial compositional change). Another way to characterize a near azeotropic composition is that the bubble point vapor pressure and dew point pressure of the composition at a particular temperature are substantially the same.

[0084] As used herein, near azeotropic compositions exhibit dew point pressure and bubble point pressure with approximately no pressure difference. That is, the difference between the dew point pressure and the bubble point pressure at a given temperature is a small value. It may be stated that compositions having a difference between the dew point pressure and the bubble point pressure of 3 percent or less (based on the bubble point pressure) may be considered to be near azeotropes.

[0085] As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," or any other variation thereof, are intended to cover non-exclusive inclusions. For example, a composition, process, method, article, or device that includes recited elements is not necessarily limited to only those elements, but may include other elements not expressly recited or inherent in such composition, process, method, article, device, etc. Furthermore, unless expressly stated to the contrary, "or" refers to an inclusive "or" and not an exclusive "or." For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0086] The transitional phrase "consisting of" excludes any unspecified element, step, or ingredient. When in a claim, such a phrase closes the claim to including materials other than those recited, except for impurities ordinarily accompanying the materials. When the phrase "consisting of" appears within a clause in the body of a claim rather than immediately following the preamble, the phrase is intended to limit only the elements set forth in that clause and does not exclude other elements from the claim as a whole.

[0087] The transitional phrase "consisting essentially of" is used to define compositions, methods, and methods that include materials, steps, mechanisms, components, or elements in addition to those literally disclosed, provided that these additionally included materials, steps, mechanisms, components, or elements do not materially affect the basic and novel characteristics of the claimed invention, particularly the mechanism of action for achieving any desired result of the inventive process. The term "consisting essentially of" has a meaning intermediate between "comprising" and "consisting of."

[0088] It should be readily understood that where applicants have defined an invention or a portion thereof with open-ended terms such as "comprising," the description (unless otherwise expressly stated) should be construed to also include such inventions using the terms "consisting essentially of" or "consisting of," including, for example, compositions consisting essentially of or consisting of.

[0089] Additionally, the use of "a" or "an" is used to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be interpreted to include one or at least one, and the singular also includes the plural unless it is clear that a different meaning is intended.

[0090] Refrigerant Blend Global warming potential (GWP) is an index for estimating the relative global warming contribution due to the atmospheric emission of one kilogram of a particular greenhouse gas compared to the emission of one kilogram of carbon dioxide. GWP can be calculated for various time horizons and indicates the impact of a given gas's atmospheric lifetime. GWP for a 100-year time horizon is the commonly referenced value. For mixtures, a weighted average can be calculated based on the individual GWPs for each component. The United Nations Intergovernmental Panel on Climate Control (IPCC) provides vetted values ​​of refrigerant GWP in its official assessment reports (ARs). The fourth assessment report is designated as AR4 and the fifth assessment report is designated as AR5. The GWP values ​​reported herein for the refrigerant blends of the present invention refer to the AR5 values.

[0091] Ozone depletion potential (ODP) is a number that indicates the amount of ozone destruction caused by a substance. ODP is the ratio of a chemical's effect on the ozone compared to the effect of a similar mass of R-11 or fluorotrichloromethane. R-11 is a type of chlorofluorocarbon (CFC) that contains chlorine, which causes ozone depletion. Further, CFC-11 is defined as having an ODP of 1.0. Other CFCs and hydrofluorochlorocarbons (HCFCs) have ODPs ranging from 0.01 to 1.0. The hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) described herein have an ODP of zero because they do not contain chlorine, bromine, or iodine, species known to contribute to ozone decomposition and destruction.

[0092] The composition comprises a refrigerant blend consisting essentially of 2,3,3,3-tetrafluoropropene (HFO-1234yf), difluoromethane (HFC-32), and 1,1-difluoroethane (HFC-152a). Suitable amounts of HFC-32 in the refrigerant blend include, but are not limited to, amounts of about 1 weight percent to 10 weight percent, or about 5 weight percent to 8 weight percent, or about 6 weight percent to 8 weight percent, or about 6 weight percent to 7.5 weight percent, or about 6 weight percent to 7 weight percent, based on the total refrigerant blend composition. Suitable amounts of HFC-152a in the refrigerant blend include, but are not limited to, amounts of about 10 weight percent to 24 weight percent, or about 12 weight percent to 24 weight percent, or about 14 weight percent to 24 weight percent, or about 14.5 weight percent to 24 weight percent, or about 14 weight percent to 18 weight percent, based on the total refrigerant blend composition. Suitable amounts of HFO-1234yf in the refrigerant blend include, but are not limited to, amounts from about 66 weight percent to 80 weight percent, or from about 69 weight percent to 80 weight percent, or from about 70 weight percent to 78 weight percent, or from about 72 weight percent to 78 weight percent based on the total refrigerant blend composition.

[0093] Specific compositions suitable for use in the heat transfer systems and methods of the present invention include the following: about 70 weight percent HFO-1234yf, about 6 weight percent HFC-32, and about 24 weight percent HFC-152a; about 74 weight percent HFO-1234yf, about 7 weight percent HFC-32, and about 19 weight percent HFC-152a; about 77 weight percent HFO-1234yf, about 3 weight percent HFC-32, and about 20 weight percent HFC-152a; about 78 weight percent HFO-1234yf, 7.5 weight percent HFC-32, and about 14.5 weight percent HFC-152a; about 78 weight percent HFO-1234yf, about 6 weight percent HFC-32, and about 16 weight percent HFC-152a; about 79 weight percent HFO-1234yf, about 3 weight percent HFC-32, and about 18 weight percent HFC-152a; about 80 weight percent HFO-1234yf, about 4 weight percent HFC-32, and about 16 weight percent HFC-152a; about 70 weight percent HFO-1234yf, about 8 weight percent HFC-32, and about 22 weight percent HFC-152a; and It contains about 67 weight percent HFO-1234yf, about 10 weight percent HFC-32, and about 23 weight percent HFC-152a.

[0094] In one embodiment, the composition comprises a refrigerant blend comprising 66-80 weight percent HFO-1234yf, 1-10 weight percent HFC-32, and 10-24 weight percent HFC-152a. In another embodiment of the invention, the refrigerant blend consists essentially of 69-80 weight percent HFO-1234yf, 5-8 weight percent HFC-32, and 12-24 weight percent HFC-152a. In another embodiment of the invention, the refrigerant blend consists essentially of 70-78 weight percent HFO-1234yf, 6-8 weight percent HFC-32, and 14-24 weight percent HFC-152a. In another embodiment of the invention, the refrigerant blend consists essentially of 70-78 weight percent HFO-1234yf, 6-7.5 weight percent HFC-32, and 14-24 weight percent HFC-152a. In another embodiment of the invention, the refrigerant blend consists essentially of 70 to 78 weight percent HFO-1234yf, 6 to 7.5 weight percent HFC-32, and 14.5 to 24 weight percent HFC-152a. In another embodiment of the invention, the refrigerant blend consists essentially of 72 to 78 weight percent HFO-1234yf, 6 to 7.5 weight percent HFC-32, and 14 to 20 weight percent HFC-152a. In another embodiment of the invention, the refrigerant blend consists essentially of 74 to 78 weight percent HFO-1234yf, 6 to 7.5 weight percent HFC-32, and 14 to 18 weight percent HFC-152a.

[0095] In some embodiments of the composition, the refrigerant blend is 78 weight percent HFO-1234yf, 8 weight percent HFC-32, and 14 weight percent HFC-152a; or A composition containing 72 weight percent HFO-1234yf, 8 weight percent HFC-32, and 20 weight percent HFC-152a is excluded.

[0096] HFO-1234yf has a very low GWP, with GWP=1(AR5). HFC-32 has a GWP=677(AR5) and HFC-152a has a GWP=138(AR5).

[0097] Thus, the final blend has 0 ODP and low GWP, or GWP<100, or preferably GWP<75, or more preferably GWP<50 (according to AR5 values). Table 1 below is a summary table showing refrigerant blends and GWP based on the Fifth Assessment Report conducted by the Intergovernmental Panel on Climate Change (IPCC) for 2,3,3,3-tetrafluoropropene (HFO-1234yf), difluoromethane (HFC-32), 1,1-difluoroethane (HFC-152a), and various combinations thereof. The refrigerant blends of the present invention can have a GWP ranging from greater than 0 and less than about 100, or greater than 0 and less than about 75.

[0098] In the case of a blend, the GWP can be calculated as a weighted average of the individual GWP values ​​in the blend, taking into account the amount (eg, weight percent) of each component in the blend.

[0099] [Table 1]

[0100] The refrigerant blends described herein operate in heat exchangers, i.e., evaporators and / or condensers, with low temperature glides, thus limiting the fraction of compositions during operation that provide efficient and consistent performance for cooling and heating.

[0101] Refrigerant blend compositions containing only HFO-1234yf and HFC-32 are known to have a higher temperature glide. The addition of HFC-152a reduces the temperature glide of the refrigerant composition. This effect is especially noticeable when the HFO-1234yf composition is greater than 70 weight percent.

[0102] In some embodiments, the refrigerant blend provides an average temperature glide of less than 4 K over the operating range of interest, more preferably the low glide is less than 3 K over the operating range of interest, more preferably less than 2.5 K over the operating range of interest, and most preferably less than 2.0 K over the operating range of interest (e.g., a glide in the range of greater than 0 to less than about 2.0 K). This effect is observed when any of the aforementioned refrigerant blends are used in a heat pump operating in heating mode.

[0103] Refrigerant Additives The compositions of the present invention containing the refrigerant blends may further contain a lubricant and may be used as heat transfer fluids. The compositions and lubricants containing the refrigerant blends of the present invention may contain additives such as stabilizers, leak detection materials, tracers and other beneficial additives.

[0104] The lubricant selected for this composition preferably has sufficient solubility in the refrigerant blend to ensure that the lubricant can return from the evaporator to the compressor. Furthermore, the miscibility should not be so great as to reduce the effective viscosity of the lubricant for lubricating the compressor. In a preferred embodiment, the lubricant and the refrigerant blend are miscible over a wide temperature range. For use in mobile air conditioning and heating, miscibility over a temperature range of about -40°C to about +40°C is desirable. Lubricants of the present invention may include polyalkylene glycol lubricants (PAGs), polyol ester lubricants (POEs), polyvinyl ether lubricants (PVEs), poly-alpha-olefins (PAOs), alkylbenzenes, mineral oils, fluorinated polyethers, and silicone lubricants.

[0105] Preferred lubricants may be one or more polyalkylene glycol type lubricants (PAG), one or more polyol ester type lubricants (POE), one or more poly-alpha-olefins (PAO), or one or more polyvinyl ether lubricants. Additionally, the lubricant for combination with the refrigerant blend of the present invention may be any mixture of PAG, POE, and / or PVE lubricants.

[0106] In one embodiment, polyalkylene glycol (PAG) oil is preferred, and may be a homopolymer or copolymer consisting of two or more oxypropylene groups.PAG oil may be uncapped, single end capped, or double end capped.Commercially available examples of PAG oil include, but are not limited to, ND-8, Castrol PAG 46, Castrol PAG 100, Castrol PAG 150, Daphne Hermetic PAG PL, and Daphne Hermetic PAG PR.

[0107] The PAG lubricant properties using them in this invention are 10 10 These include a volume resistivity of greater than Ω-m, a surface tension of about 0.02 N / m to about 0.04 N / m at 20° C., a kinematic viscosity of about 20 cSt to about 500 cSt at 40° C., a dielectric breakdown voltage of at least 25 kV, and a hydroxyl number of at most 0.1 mg KOH / g.

[0108] In one aspect of this embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 66-80 weight percent HFO-1234yf, about 1-10 weight percent HFC-32, and about 10-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 69-80 weight percent HFO-1234yf, about 5-8 weight percent HFC-32, and about 12-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-8 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-7.5 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 72-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-20 weight percent HFC-152a. In another embodiment, the lubricant comprises a PAG and the refrigerant consists essentially of about 74-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-18 weight percent HFC-152a. In a further aspect, the refrigerant composition further comprises greater than about 0 and less than 1 weight percent of an additional compound.

[0109] POE lubricants are typically formed by the chemical reaction (esterification) of a carboxylic acid or mixture of carboxylic acids with an alcohol or mixture of alcohols.

[0110] In one embodiment, as used herein, polyol esters include esters of diols or polyols having about 3 to 20 hydroxyl groups and carboxylic acids (or fatty acids) having about 1 to 24 carbon atoms, which are preferably used as polyols. Esters that can be used as base oils are described in the published European patent application according to Art. 153(4) EP 2 727 980 A1, which is incorporated herein by reference. Examples of the diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0111] Examples of the polyols include polyhydric alcohols such as trimethylolethane, trimethylolpropane, trimethylolbutane, di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol, di(pentaerythritol), tri(pentaerythritol), glycerin, polyglycerin (glycerin dimer to decamer), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol-glycerin condensates, adonitol, arabitol, xylitol, mannitol, and the like; polysaccharides such as, in particular, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffinose, gentianose, melezitose; partial etherification products thereof, and methyl glucoside, and the like. Among these, hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol, di(pentaerythritol), and tri(pentaerythritol) are preferred as polyols.

[0112] The number of carbon atoms of the fatty acid is not particularly limited, but generally, fatty acids having 1 to 24 carbon atoms are used. Among fatty acids having 1 to 24 carbon atoms, from the viewpoint of lubrication properties, fatty acids having 3 or more carbon atoms are preferred, fatty acids having 4 or more carbon atoms are more preferred, fatty acids having 5 or more carbon atoms are even more preferred, and fatty acids having 10 or more carbon atoms are most preferred. Furthermore, from the viewpoint of compatibility with the refrigerant, fatty acids having 18 or less carbon atoms are preferred, fatty acids having 12 or less carbon atoms are more preferred, and fatty acids having 9 or less carbon atoms are even more preferred. In one embodiment, the carboxylic acid has 2 to 18 carbon atoms.

[0113] Furthermore, the fatty acid may be either a straight-chain fatty acid or a branched-chain fatty acid, and from the viewpoint of lubrication properties, the straight-chain fatty acid is preferred, while from the viewpoint of hydrolysis stability, the branched-chain fatty acid is preferred.Furthermore, the fatty acid may be either a saturated fatty acid or an unsaturated fatty acid.Specifically, examples of the fatty acid include straight-chain or branched-chain fatty acids, such as pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, oleic acid, and the like; and the so-called neo acid, in which a carboxylic acid group is bonded to a quaternary carbon atom. More specifically, preferred examples thereof include valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), pelargonic acid (n-nonanoic acid), capric acid (n-decanoic acid), oleic acid (cis-9-octadecanoic acid), isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, etc. Incidentally, the polyol ester may be a partial ester in which the hydroxyl groups of the polyol are not completely esterified and remain; a complete ester in which all the hydroxyl groups are esterified; or a mixture of a partial ester and a complete ester, and a complete ester may be preferred in some cases.

[0114] In the polyol ester, from the viewpoint of better hydrolytic stability, esters of hindered alcohols such as neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, di(trimethylolpropane), tri(trimethylolpropane), pentaerythritol, di(pentaerythritol), tri(pentaerythritol) and the like are more preferred, and esters of neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, or pentaerythritol are even more preferred; from the viewpoint of particularly good compatibility with refrigerants and hydrolytic stability, esters of pentaerythritol are most preferred.

[0115] Specific preferred examples of polyol esters include diesters of neopentyl glycol and one or more fatty acids selected from valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolethane and one or more fatty acids selected from valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolpropane and one or more fatty acids selected from valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolbutane and one or more fatty acids selected from valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; triesters of trimethylolbutane and one or more fatty acids selected from valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid; tetraesters of pentaerythritol and one or more fatty acids selected from valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid. Incidentally, the ester of two or more fatty acids may be a mixture of two or more esters of one fatty acid and a polyol, and an ester of two or more mixed fatty acids and a polyol. In particular, the ester of a mixed fatty acid and a polyol is excellent in low-temperature properties and compatibility with refrigerants.

[0116] POE lubricants used in electric vehicle air conditioning and heating applications may have a kinematic viscosity (measured at 40°C according to ASTM D445) of 20 to 500 cSt, or 75 to 110 cSt, ideally about 80 cSt to 100 cSt, and most specifically 85 cSt to 95 cSt. However, it should be noted that, without being limiting to the invention, other lubricant viscosities may be mentioned depending on the needs of the heat pump compressor of the electric vehicle. Suitable characteristics of automotive POE type lubricants for use with the compositions of the present invention are listed below.

[0117] [Table 2]

[0118] In one embodiment, the lubricant comprises POE, the POE being stable upon exposure to the composition of the present invention, and the refrigerant composition has an F-ion content of less than about 500 ppm, optionally greater than 0 and less than 500 ppm, greater than 0 and less than 100 ppm, optionally greater than 0 and less than 50 ppm. In one aspect of this embodiment, the refrigerant consists essentially of about 66 to about 80 weight percent, preferably about 70 to 78 weight percent, or about 72 to 78 weight percent, or about 74 to 78 weight percent HFO-1234yf, about 2 to 8 weight percent, or 6 to 7.5 weight percent HFC-32, and about 14 to 24 weight percent, or about 14.5 to 24 weight percent, or about 14 to 20 weight percent, or about 14 to 18 weight percent HFC-152a. In a further embodiment, the refrigerant composition further comprises greater than about 0 and less than 1 weight percent of an additional compound.

[0119] In one embodiment, the lubricant comprises POE and is stable upon exposure to the compositions of the present invention, and the refrigerant blend composition has a Total Acid Number (TAN), mg KOH / g, less than about 1, greater than 0 and less than 1, greater than 0 and less than about 0.75, and in some cases greater than 0 and less than about 0.4. In one aspect of this embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 66-80 weight percent HFO-1234yf, about 1-10 weight percent HFC-32, and about 10-24 weight percent HFC-152a. In another embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 69-80 weight percent HFO-1234yf, about 5-8 weight percent HFC-32, and about 12-24 weight percent HFC-152a. In another embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-8 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-7.5 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 72-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-20 weight percent HFC-152a. In another embodiment, the lubricant comprises POE and the refrigerant consists essentially of about 74-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-18 weight percent HFC-152a. In a further aspect, the refrigerant composition further comprises greater than about 0 and less than 1 weight percent of an additional compound.

[0120] In another embodiment, PVE lubricants can be included as lubricants in the compositions of the present invention.Without limiting the scope of the present invention in any way, in one embodiment of the present invention, the polyvinyl ether oil includes those taught in the literature, such as those described in U.S. Patent Nos. 5,399,631 and 6,454,960.In another embodiment of the present invention, the polyvinyl ether oil is composed of structural units of the type shown by formula 1. -[C(R1,R2)-C(R3,-R4)]- Equation 1 wherein R1, R2, R3, and R4 are independently selected from hydrogen and a hydrocarbon, which may optionally contain one or more ether groups. In a preferred embodiment of the present invention, R1, R2, and R3 are each hydrogen, as shown in Formula 2. -[CH2-CH(-O-R4]- Formula 2

[0121] In another embodiment of the present invention, the polyvinyl ether oil is composed of structural units of the type shown by formula 3. -[CH2-CH(-O-R5)] m -[CH2-CH(-O-R6)] n formula 3 wherein R5 and R6 are independently selected from hydrogen and a hydrocarbon, and m and n are integers.

[0122] In one embodiment, the polyvinyl ether oil comprises a copolymer of the following two units:

[0123] [ka]

[0124] The properties of the lubricant (viscosity, refrigerant solubility and miscibility with the refrigerant) can be adjusted by varying the ratio of n / n and the sum of m+n. In another embodiment, the PVE lubricant is one that is 50 to 95 weight percent of unit 1.

[0125] In one aspect of this embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 66-80 weight percent HFO-1234yf, about 1-10 weight percent HFC-32, and about 10-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 69-80 weight percent HFO-1234yf, about 5-8 weight percent HFC-32, and about 12-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-8 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-7.5 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 70-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-24 weight percent HFC-152a. In another embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 72-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-20 weight percent HFC-152a. In another embodiment, the lubricant comprises a PVE and the refrigerant consists essentially of about 74-78 weight percent HFO-1234yf, about 6-7 weight percent HFC-32, and about 14-18 weight percent HFC-152a. In a further aspect, the refrigerant composition further comprises greater than about 0 and less than 1 weight percent of an additional compound.

[0126] Similar properties and characteristics may be required for the use of PVE lubricants in the compositions described herein as for POE lubricants, particularly for use in automotive cooling and heating systems.

[0127] In a preferred embodiment, the lubricant is soluble in the refrigerant at temperatures between about −40° C. and about 80° C., more preferably in the range of about −30° C. to about 40° C., and even more specifically at temperatures between −25° C. and 40° C. In another embodiment, high temperature insolubility is not preferred, since attempting to maintain the lubricant within the compressor is not a priority.

[0128] The amount of lubricant can range from about 1 to about 20 weight percent, from about 1 to about 7 weight percent, and in some cases from about 1 to about 3 weight percent.

[0129] To limit hydrolysis of the lubricating oil, the water concentration in the heating / cooling systems of electric type vehicles must be controlled, and therefore the lubricant of this embodiment must be low in water, typically less than 100 ppm by weight.

[0130] In a preferred embodiment, the lubricant comprises a POE lubricant that is soluble in the refrigerant of the vehicle heat pump system at temperatures within the range of about -35°C to about 100°C, more preferably about -35°C to about 50°C, and even more specifically, at temperatures between -30°C and 40°C. In another preferred embodiment, the POE lubricant is soluble at temperatures above about 70°C, more preferably above about 80°C, and most preferably at temperatures between 90°C and 95°C.

[0131] Of particular note are PAG, POE, PAO, and PVE lubricants having: 10 having a volume resistivity of greater than Ω-m, a surface tension of about 0.02 N / m to about 0.04 N / m at 20° C.; a kinematic viscosity of about 20 cSt to about 500 cSt, or about 50 cSt to about 200 cSt, or about 75 cSt to about 100 cSt at 40° C.; a breakdown voltage that is at least 25 kV, and a hydroxyl number that is at most 0.1 mg KOH / g.

[0132] Due to the presence of double bonds, HFO type refrigerants can be thermally unstable and decompose under extreme use, handling or storage conditions. Therefore, it may be advantageous to add stabilizers to HFO type refrigerants. Stabilizers may include, among others, nitromethane, ascorbic acid, terephthalic acid, azoles such as tolutriazole or benzotriazole, phenolic compounds such as tocopherol, hydroquinone, t-butylhydroquinone, 2,6-di-tertbutyl-4-methylphenol, epoxides (possibly fluorinated or perfluorinated alkyl epoxides or alkenyl or aromatic epoxides) such as n-butyl glycidyl ether, hexanediol diglycidyl ether, allyl glycidyl ether, butylphenyl glycidyl ether, cyclic monoterpenes, terpenes such as d-limonene, α-terpinene, β-terpinene, γ-terpinene, α-pinene or β-pinene, phosphites, phosphates, phosphonates, thiols and lactones. Examples of suitable stabilizers are disclosed in WO 2019213004, WO 2020222864, and WO 2020222865, the disclosures of which are incorporated herein by reference.

[0133] The blends may or may not contain a stabilizer, depending on the requirements of the system they are being used in. If the refrigerant blend contains a stabilizer, the refrigerant blend may contain any amount from 0.001% to 1% by weight, preferably from about 0.01 to about 0.5% by weight, and more preferably from about 0.01 to about 0.3% by weight of any of the stabilizers listed above, in most cases preferably d-limonene.

[0134] In some embodiments, the compositions disclosed herein may contain a tracer compound(s). The tracer may include two or more tracer compounds. In some embodiments, the tracer is present in the composition at a total concentration of about 50 parts per million (ppm) to about 1000 ppm, based on the weight of the total composition. In other embodiments, the tracer is present at a total concentration of about 50 ppm to about 500 ppm. Alternatively, the tracer is present at a total concentration of about 100 ppm to about 300 ppm.

[0135] A tracer may be added to the composition of the present invention in a predetermined amount to allow detection of any dilution, adulteration, or other alteration of the composition. The presence of a particular compound in the composition may indicate by which method or process one of the components was produced. A tracer may also be added to the composition in a specific amount to identify the source of the composition. In this way, detection of patent infringement can be achieved. The tracer may be a refrigerant compound, but is present in the composition at a level that is unlikely to affect the performance of the refrigerant component of the composition.

[0136] The tracer compound may be a hydrofluorocarbon, a hydrofluoroolefin, a hydrochlorocarbon, a hydrochloroolefin, a hydrochlorofluorocarbon, a hydrochlorofluoroolefin, a hydrochlorocarbon, a hydrochloroolefin, a chlorofluoroolefin, a hydrocarbon, a perfluorocarbon, a perfluoroolefin, and combinations thereof. Examples of tracer compounds are HFC-23 (trifluoromethane), HCFC-31 (chlorofluoromethane), HFC-41 (fluoromethane), HFC-161 (fluoroethane), HFC-143a (1,1,1-trifluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HFC-125 (pentafluoroethane), HFC-236fa (1,1,1,3,3,3-hexafluoropropane), HFC-236 ea (1,1,1,2,3,3-hexafluoropropane), HFC-245cb (1,1,1,2,2-pentafluoropropane), HFC-245fa (1,1,1,3,3-pentafluoropropane), HFC-254eb (1,1,1,2-tetrafluoropropane), HFC-263fb (1,1,1-trifluoropropane), HFC-272ca (2,2-difluoropropane), HFC-281ea (2-fluoropropane), H FC-281fa (1-fluoropropane), HFC-329p (1,1,1,2,2,3,3,4,4-nonafluorobutane), HFC-329mmz (1,1,1-trifluoro-2-methylpropane), HFC-338mf (1,1,1,2,2,4,4,4-octafluorobutane), HFC-338pcc (1,1,2,2,3,3,4,4-octafluorobutane), CFC-12 (dichlorodifluoromethane), CFC-11 (trifluorobutane), chlorofluoromethane), CFC-114 (1,2-dichloro-1,1,2,2-tetrafluoroethane), CFC-114a (1,1-dichloro-1,2,2-tetrafluoroethane), HCFC-22 (chlorodifluoromethane), HCFC-123 (1,1-dichloro-2,2,2-trifluoroethane), HCFC-124 (2-chloro-1,1,1,2-tetrafluoroethane), HCFC-124a (1-chloro-1,1,2,2-tetrafluoroethane), HCFC-141b (1,1-dichloro-1-fluoroethane), HCFC-142b (1-chloro-1,1-difluoroethane), HCFC-151a (1-chloro-1-fluoroethane), HCFC-244bb (2-chloro)-1,1,1,2-tetrafluoropropane), HCC-40 (chloromethane), HFO-1141 (fluoroethene), HCFO-1130 (1,2-dichloroethene), HCFO-1130a (1,1-dichloroethene), HCFO-1131 (1-chloro-2-fluoroethene), HCFO-1122 (2-chloro-1,1-difluoroethene), HFO-1123 (1,1,2-trifluoroethene), HFO-1234ye (1,2,3,3-tetrafluoropropene) HFO-1243zf (3,3,3-trifluoropropene), HFO-1225ye (1,2,3,3,3-pentafluoropropene), HFO-1225zc (1,1,3,3,3-pentafluoropropene), PFC-116 (hexafluoroethane), PFC-C216 (hexafluorocyclopropane), PFC-218 (octafluoropropane), PFC-C318 (octafluorocyclobutane), PFC-1216 (hexafluoroethane), PFC-31-10mc (1,1,1,2,2,3,3,4,4,4-decafluorobutane), PFC-31-10my (1,1,1,2,3,3,3-heptafluoro-2-trifluoromethylpropane), and combinations thereof.

[0137] Flammability of refrigerant blends Flammability is a term used to mean the ability of a composition to ignite and / or propagate a flame. For refrigerants and other heat transfer compositions or working fluids, the lower flammability limit ("LFL") is the lowest concentration of the heat transfer composition in air that can propagate a flame through a homogeneous mixture of the composition and air under the test conditions described in ASTM (American Society of Testing and Material) E681. The upper flammability limit ("UFL") is the highest concentration of the heat transfer composition in air that can propagate a flame through a homogeneous mixture of the composition and air under the same test conditions.

[0138] To be classified as non-flammable (Class 1, no flame spread) per ANSI / ASHRAE Standard 34 or ISO 817 ISO 817:2014(en) Refrigerants-Designation and Safety Classification, a refrigerant must meet the conditions of ASTM E681 when formulated in both the liquid and vapor phases, and must be non-flammable in both the liquid and vapor phases obtained during a leak scenario as defined by ANSI / ASHRAE Standard 34:2019 or ISO 817:2014(en) Refrigerants-Designation and Safety Classification.

[0139] For a refrigerant blend to be classified as low flammable (Class 2L) by ANSI / ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers), the worst case formula (WCF) and worst case flammability fraction (WCFF) of the refrigerant blend must be determined based on manufacturing tolerances and vapor leakage behavior. To be classified as 2L, low flammable, the WCF and WCFF must: 1) exhibit flame propagation when tested at 140°F (60°C) and 14.7 psia (101.3 kPa) and have an LFL > 0.0062 lb / ft 3 (0.10kg / m 3 ) and 2) have a maximum burning velocity of ≦3.9 in. / s (10 cm / s) when tested at 73.4°F (23.0°C) and 14.7 psia (101.3 kPa). Additionally, the nominal refrigerant blend must have a heat of combustion of less than 8169 Btu / lb (19,000 kJ / kg).

[0140] ASHRAE Standard 34 provides a method for calculating the heat of combustion of refrigerant blends using a balanced stoichiometric equation based on the complete combustion of one mole of refrigerant with sufficient oxygen for the stoichiometric reaction.

[0141] When the HFO-1234yf, HFC-32, and HFC-152a components are blended in certain proportions, the resulting blend has Class 2L flammability as defined by ANSI / ASHRAE Standard 34 and ISO 817. Class 2L flammability is inherently less flammable (i.e., lower energy release as exemplified by heat of combustion, or HOC, values) than both Class 2 and Class 3 flammability and can be managed in automotive heating / cooling systems.

[0142] Compositions of the invention comprising, consisting essentially of, or consisting of 72-78 weight percent HFO-1234yf, 6-7.5 weight percent HFC-32, and 14-20 weight percent HFC-152a, or 74-78 weight percent HFO-1234yf, 6-7.5 weight percent HFC-32, and 14-18 weight percent HFC-152a, are classified as Class 2L flammable by ASHRAE, with an LFL of less than 10 volume percent and a burn velocity of less than 10 cm / sec. In particular, a composition consisting essentially of about 78 weight percent HFO-1234yf, about 7.5 weight percent HFC-32, and about 14.5 weight percent HFC-152a meets all the requirements and is classified as Class 2L, low flammable by ASHRAE. In another embodiment, a composition consisting essentially of 78 weight percent HFO-1234yf (tolerance +1.0 / -1.0 wt%), about 7.5 weight percent HFC-32 (tolerance +0.5 / -1.5 wt%), and about 14.5 weight percent HFC-152a (tolerance +0.5 / -1.5 wt%) meets all of the requirements and is classified by ASHRAE as Class 2L, low flammability.

[0143] In embodiments, the refrigerant blend includes 2,3,3,3-tetrafluoropropene (HFO-1234yf), difluoromethane (HFC-32), and 1,1-difluoroethane (HFC-152a). In some embodiments, the refrigerant blend can include, consist essentially of, or consist of 2,3,3,3-tetrafluoropropene (HFO-1234yf), difluoromethane (HFC-32), and 1,1-difluoroethane (HFC-152a). In some embodiments, the refrigerant blend may comprise, consist essentially of, or consist of about 66 weight percent to 80 weight percent, or about 69 weight percent to 80 weight percent, or about 70 weight percent to 78 weight percent, or about 72 weight percent to 78 weight percent, or about 74 weight percent to 78 weight percent HFO-1234y, about 1 weight percent to 10 weight percent, or about 5 weight percent to 8 weight percent, or about 6 weight percent to 8 weight percent, or 6 weight percent to 7.5 weight percent, or 6 weight percent to 7 weight percent HFC-32; and about 10 weight percent to 24 weight percent, or about 12 weight percent to 24 weight percent, or about 14 weight percent to 24 weight percent, or about 14.5 weight percent to 24 weight percent, or about 14 weight percent to 20 weight percent, or about 14 weight percent to 18 weight percent HFC-152af.

[0144] In one embodiment, any of the foregoing refrigerant compositions can further comprise at least one additional compound selected from the group consisting of HCFC-244bb, HFC-245cb, HFC-254eb, HFO-1234ze, CFC-12, HCFC-124, 3,3,3-trifluoropropyne, HCC-1140, HFC-1225ye, HFO-1225zc, HFC-134a, HFO-1243zf, and HCFO-1131.

[0145] In one embodiment, any of the foregoing refrigerant compositions may further comprise at least one additional compound selected from the group consisting of HFC-23, HCFC-31, HFC-41, HFC-143a, HCFC-22, HCC-40, HFC-161, HFO-1141, HCO-1140, HCFC-151a, HCFO-1130a, HCFC-141b, HFO-1132a, HFC-143a, HCFO-1122, and HCFC-142b.

[0146] In one embodiment, any of the foregoing refrigerant compositions may further comprise at least one additional compound selected from the group consisting of HFC-143a, HCC-40, HFC-161, and HCFC-151a. Alternatively, the composition may comprise HFC-143a, HCC-40, HFC-161, and HCFC-151a.

[0147] In one embodiment, any of the foregoing refrigerant compositions may further comprise at least one additional compound selected from the group consisting of HFO-1243zf, 3,3,3-trifluoropropyne, HFC-143a, HCC-40, HFC-161, and HCFC-151a. Alternatively, the composition may comprise HFO-1243zf, HFC-143a, HCC-40, HFC-161, and HCFC-151a.

[0148] The amount of the additional compound present in any of the foregoing refrigerant compositions can be greater than 0 ppm and less than 5,000 ppm, particularly in the ranges of from about 5 to about 1,000 ppm, from about 5 to about 500 ppm, and from about 5 to about 100 ppm.

[0149] In one embodiment, the amount of additional compounds present in any of the aforementioned refrigerant compositions may be greater than 0 and less than 1% by weight of the refrigerant composition, preferably less than 0.5% by weight, or more preferably less than 0.1% by weight.

[0150] In one embodiment, any of the aforementioned refrigerant compositions can further comprise additional compounds including at least one of oligomers and / or homopolymers of 1234yf. The amount can range from greater than 0 and about 100 ppm, and in some cases from about 2 ppm to about 100 ppm. In one aspect of this embodiment, the refrigerant comprises about 70-78 wt% HFO-1234yf, about 6-8 wt% or 6-7.5 wt% HFC-32, and about 14-24 wt% HFC-152a, and in a further aspect, the refrigerant composition further comprises, in addition to the oligomers and homopolymers, greater than about 0 and less than 1 wt%, preferably less than 0.5 wt%, and even more preferably less than 0.1 wt% of additional compounds.

[0151] Another embodiment of the invention relates to storing any of the aforementioned compositions in a gas and / or liquid phase in a sealed container. The water concentration in the gas and / or liquid phase in the sealed container ranges from about 0.1 to 200 ppm by weight. The oxygen concentration in the gas and / or liquid phase in the sealed container ranges from about 10 ppm by volume to about 0.35% by volume at about 25° C. The air concentration in the gas and / or liquid phase in the sealed container ranges from about 100 ppm by volume to about 1.5% by volume.

[0152] The container for storing the aforementioned composition can be constructed of any suitable material and design that can seal the composition while maintaining the gas and liquid phases. Examples of suitable containers include pressure vessels such as tanks, filled cylinders, and secondary filled cylinders. The container can be constructed from any suitable material such as carbon steel, manganese steel, chromium-molybdenum steel, especially low alloy steel, stainless steel, and in some cases aluminum alloy.

[0153] The compositions of the present invention can be prepared by any convenient method for combining the desired amounts of individual components. A preferred method is to weigh the desired amounts of components and then combine the components in a suitable vessel. Agitation may be used if desired. In another embodiment, any of the aforementioned refrigerant compositions can be prepared by blending at least one of HFO-1234yf, HFC-32, and HFC-152a, and optionally additional compounds.

[0154] In further embodiments, compositions may be prepared from recycled or regenerated refrigerants. One or more components may be recycled or regenerated by removing contaminants such as air, water, or residues that may include lubricants or particulate residues from the system components. Means for removing contaminants may vary widely, but may include distillation, decantation, filtration, and / or drying with the use of molecular sieves or other absorbents. The recycled or regenerated component(s) may then be combined with other component(s) as described above.

[0155] In one embodiment of the present invention, a system for heating and cooling the passenger compartment of an electric vehicle is provided. The system includes an evaporator, a compressor, a condenser, and an expansion device, each operatively connected to perform a vapor compression cycle, and the system contains any of the aforementioned compositions, including a refrigerant blend consisting essentially of HFO-1234yf, HFC-32, and HFC-152a. The average temperature glide in the system of the present invention is less than 4 K, preferably less than 3 K, and most preferably less than 2.5 K. The system is preferably a heat pump. Due to the superior performance of the heat pump system in both cooling and heating the passenger compartment of the electric vehicle, the system no longer requires a positive temperature coefficient (PTC) heater.

[0156] The refrigerant blends can be used in a variety of heating and cooling systems. In some embodiments, a reversing valve is used and the same loop is used for cooling and heating. In other embodiments, an air-side bypass or refrigerant valve / system design modifications can achieve the same effect as a reversible cycle without a reversing valve.

[0157] In the embodiment of Figure 1, a refrigeration system 100 having a refrigeration loop 110 comprises a first heat exchanger 120, a pressure regulator 130, a second heat exchanger 140, a compressor 150, and a four-way valve 160. The first and second heat exchangers are of the air / refrigerant type. The refrigerant of the loop 110 and the air flow generated by the fan pass through the first heat exchanger 120.

[0158] In cooling mode, the refrigerant started by the compressor 150 passes through valve 160, passes through heat exchanger 120 which acts as a condenser, i.e., gives up thermal energy to the outside, then passes through pressure regulator 130 and then through heat exchanger 140 which acts as an evaporator, thereby cooling the air flow intended to be blown into the interior of the vehicle cabin.

[0159] In heat pump mode, the direction of refrigerant flow is reversed using valve 160. Heat exchanger 140 functions as a condenser while heat exchanger 120 functions as an evaporator. Heat exchanger 140 can then be used to heat a flow of air that is directed into the passenger compartment of the vehicle.

[0160] Additional heat transfer loops may be connected to the heat pump system to absorb or reject heat in heat exchangers 120 and / or 140 to allow for the transfer of heat from the motor or battery, thus serving to provide thermal management of those components of the vehicle as well as cooling and heating for the passenger compartment.

[0161] In the embodiment of Fig. 2, a refrigeration system 300 with a refrigeration loop 310 comprises a first heat exchanger 320, a pressure regulator 330, a second heat exchanger 340, a compressor 350 and a four-way valve 360. The first heat exchanger 320 and the second heat exchanger 340 are of the air / refrigerant type. The way in which the heat exchangers 320 and 340 work is the same as in the first embodiment shown in Fig. 1. Two fluid / liquid heat exchangers 370 and 380 are installed both in the refrigeration loop circuit 310 and in the engine cooling circuit or in the secondary glycol-water circuit. The installation of the fluid / liquid heat exchangers without passing an intermediate gaseous fluid (air) contributes to an improved heat exchange compared to an air / fluid heat exchanger.

[0162] In the embodiment of FIG. 3, a refrigeration system 400 having a refrigeration loop 410 includes a first heat exchanger (condenser) 420, a pressure regulator 430, a second heat exchanger (evaporator) 440, a compressor 450, a three-way valve 460, and a third heat exchanger (for reheat) 470. In a cooling mode, at least a portion of the discharge flow from the compressor 450 is directed through the three-way valve 460 to the third heat exchanger 470. The outlet flow from the third heat exchanger 470 is discharged to the inlet of the first heat exchanger 420. The refrigerant is condensed by the first heat exchanger 420 using an external fan 480 and ambient air as a heat sink. The existing saturated or subcooled liquid is expanded in the pressure regulator 430, and the resulting low-pressure saturated mixture of refrigerant liquid and vapor enters the second heat exchanger 440. The refrigerant is evaporated in the second heat exchanger 440 by use of a second fan 490, which is external to the cooling loop. Air passing through the second heat exchanger 440 is cooled below the air dew point temperature. This causes the moisture in the air to partially condense, lowering the absolute humidity of the air. The air then passes through the third heat exchanger 470, which transfers heat to the air, raising the air temperature above the dew point and lowering the relative humidity of the air, which is then supplied to the passenger compartment. This process of cooling below the dew point temperature to remove moisture, followed by reheating to a temperature above the dew point temperature allows for cooling and relative humidity control of the vehicle passenger compartment. In the heating mode, the three-way valve 460 is adjusted to prevent the flow of refrigerant to the heat exchanger 420, and all vehicle passenger compartment heating is achieved using the second heat exchanger 470 in the heat pump configuration described in FIG. 1.

[0163] In the embodiment of FIG. 4, air conditioning (AC) and heat pump (HP) system 500, heating, cooling, or both can be accomplished within the vehicle passenger compartment or for other vehicle loads. System 500 includes AC circuit 510 and HP circuit 520. In air conditioning only mode, HP control valve 530 upstream of heat pump condenser 540 is closed and refrigerant flows from compressor 550 to air-cooled AC condenser 560, through AC expansion valve 570 and into AC evaporator 580 to provide cooling to the passenger compartment. From AC evaporator 580, refrigerant returns to compressor 550. In heat pump only mode, AC control valve 535 upstream of AC condenser 560 is closed and refrigerant flows from compressor 550 to HP condenser 540 to heat the passenger compartment. From HP condenser 540, refrigerant flows through HP expansion valve 575 to HP evaporator 585. The separate humidity control modes can be achieved by directing a portion of the compressor exhaust gas to the AC circuit 510 and the remaining portion to the HP circuit 520.

[0164] In the embodiment of FIG. 5, a system 600 for heating, cooling, or both can be implemented for a vehicle cabin or other vehicle loads. The system 600 includes an AC circuit 610 and a water-cooled / HP circuit 620. In an AC-only mode, a water loop control valve 630 upstream of a water-cooled condenser 660 is closed, and refrigerant flows from a compressor 650 to an AC condenser 640, through an AC expansion valve 670, and into an AC evaporator 680 to provide cooling to the cabin. In an HP-only mode, an AC control valve 635 upstream of the AC condenser 640 is closed, and refrigerant flows from a compressor 650 to a water-cooled condenser 660. A heat transfer fluid (e.g., water or other heat transfer fluid) receives heat generated in the water-cooled condenser 640 and transfers it to a cabin heater core 690 to provide heat to the cabin. The heat transfer fluid can return from the cabin heater core 690 to the water-cooled condenser 640. Refrigerant flows from the water-cooled condenser 640, through an HP expansion valve 675, into an HP evaporator 685 which cools the heat transfer fluid, which may be used to cool other components of the vehicle, and then returns to the compressor 650. In some embodiments, there are one or more water / heat transfer fluid loops that may be used to heat and / or cool various other components of the vehicle. Separate humidity control modes can be achieved by sending a portion of the compressor exhaust gas to the AC circuit 610 and the remaining portion to the water cooling / HP circuit 620.

[0165] In the embodiment of Figures 7-10, the same components are present in the system, but depending on the mode of operation, only some of the components are utilized.

[0166] In one embodiment, in a heating mode, where certain conditions exist where both the vehicle cabin and other vehicle components require heat, the refrigerant circuit 700 operates as shown in FIG. 7. Starting from the compressor 750, the exiting refrigerant vapor takes two paths. One path is through the cabin condenser 740. The cabin condenser 740 is typically a fin-tube or microchannel type refrigerant-to-air heat exchanger, which can be single-pass or multi-pass. A first fan 745 in the vehicle ventilation duct directs a flow of either 100% outside air or a mixture of outside air and return air from the vehicle cabin across this cabin condenser 740, where the refrigerant heats the air as it condenses. In this mode, a physical bypass 735 in the vehicle ventilation duct prevents air from flowing past the cabin evaporator 730. The second path of the refrigerant leaving the compressor is through a valve 770 and into the liquid / heat transfer fluid heat exchanger 720, which allows heat to be transferred from the warm refrigerant to the vehicle's heat transfer fluid loop (not shown). This vehicle heat transfer loop can then be used to manage other vehicle heat loads. The heat transfer fluid in the heat transfer fluid loop may be water or a water / glycol solution. The condensed refrigerant leaving the exchanger 720 then merges with the liquid refrigerant outlet of the condenser 740 and the combined flow flows through an expansion device 775 which reduces the pressure of the liquid refrigerant to produce a liquid-vapor mixture. This liquid-vapor mixture then flows through an exterior heat exchanger 780 (i.e., an evaporator in this configuration). The exterior heat exchanger 780 is typically a fin-tube or microchannel type refrigerant-to-air heat exchanger and may be single-pass or multi-pass. A second fan 785 induces airflow across the exterior heat exchanger 780, allowing the liquid-vapor refrigerant mixture to absorb heat from the ambient air and completely evaporate before returning to the compressor 750.

[0167] In another embodiment, in a heating mode when certain conditions exist where only cabin heating is required, the refrigerant circuit 800 operates as shown in FIG. 8. Starting from the compressor 850, the exhaust vapor first flows through the cabin condenser 840. A first fan 845 in the vehicle ventilation duct induces a flow of either 100% outside air or a mixture of outside air and return air from the vehicle cabin across this cabin condenser 840, and the refrigerant exchanges heat between the condenser 840 and the air. In this mode, a physical bypass 835 in the vehicle ventilation duct prevents air from flowing past the cabin evaporator 830. The refrigerant condenses in the cabin condenser 840 and flows to an expansion device 875, which reduces the pressure of the liquid refrigerant and creates a liquid-vapor mixture. This liquid-vapor mixture flows through an exterior heat exchanger 880 (i.e., the evaporator in this configuration). A second fan 885 induces airflow across the exterior heat exchanger 880 , allowing the liquid-vapor refrigerant mixture to absorb heat from the ambient air and completely evaporate before returning to the compressor 850 .

[0168] In another embodiment, in a cooling mode when certain conditions exist that require cooling for both the vehicle cabin and vehicle components, the refrigerant circuit 900 operates as shown in FIG. 9. Starting from the compressor 950, the exhaust refrigerant vapor first flows through the cabin condenser 940, and in this mode, there is no heat transfer because a physical bypass 945 in the vehicle ventilation duct prevents air from flowing past the cabin condenser 940. The vapor refrigerant passes through the cabin condenser 940 and flows through a valve 975 into the exterior heat exchanger 980. In this mode, the exterior heat exchanger 980 functions as a condenser as a first fan 985 induces flow across the heat exchanger, causing the hot refrigerant vapor to exchange heat and condense into a liquid. A portion of this liquid refrigerant exits the exterior heat exchanger 980 and enters the interior heat exchanger 990. The liquid refrigerant is subcooled in the interior heat exchanger 990 and then flows to the expansion device 910 and into the cabin evaporator 930. This air-refrigerant cabin evaporator 930 is a fin-tube or microchannel type heat exchanger and can be single-pass or multi-pass. A second fan (or cabin blower fan) 935 directs a flow of either 100% outside air or a mixture of outside air and return air from the cabin across the coils of the cabin evaporator 930 where heat is exchanged between the air and the refrigerant. The refrigerant evaporates and returns to the interior heat exchanger 990 where it is further superheated before finally re-entering the compressor 950. The remaining portion of the refrigerant exiting the condenser 980 flows through the expansion valve 915 to the liquid / heat transfer fluid heat exchanger 920 where the heat of the vehicle components is transferred to the refrigerant via a heat transfer fluid loop (not shown). This vehicle heat transfer loop can then be used to manage other vehicle heat loads. The refrigerant evaporates in the heat exchanger 920 and meets with the refrigerant exiting the interior heat exchanger 990 at the inlet of the compressor 950.

[0169] In another embodiment, in cooling mode when certain conditions exist where only vehicle cabin cooling is required, the refrigerant circuit 1000 operates as shown in FIG. 10. Starting from the compressor 1050, the exhaust refrigerant vapor first flows through the cabin condenser 1040, and in this mode, there is no heat transfer as a physical bypass 1045 in the vehicle ventilation duct prevents air from flowing past the cabin condenser 1040. The vapor refrigerant passes through the cabin condenser 1040 and flows through a valve 1075 to the exterior heat exchanger 1080. In this mode, the exterior heat exchanger 1080 functions as a condenser as the first fan 1085 induces flow across the heat exchanger 1080, causing the hot refrigerant vapor to exchange heat and condense into a liquid. This liquid refrigerant exits the exterior heat exchanger 1080 and enters the interior heat exchanger 1090. The liquid refrigerant is subcooled in the internal heat exchanger 1090 and then flows to the expansion device 1010 and into the cabin evaporator 1030. A second fan (or cabin blower fan) 1035 directs a flow of either 100% outside air or a mixture of outside air and return air from the cabin across the cabin evaporator 1030 where heat is exchanged between the air and the refrigerant. The refrigerant evaporates and returns to the internal heat exchanger 1090 where it is further superheated before finally returning to the compressor 1050.

[0170] The blends have low GWP, low toxicity and low flammability with low temperature glide for use in hybrid, mild hybrid, plug-in hybrid or fully electric vehicles for passenger compartment thermal management (heat transfer from one part of the vehicle to another) to provide air conditioning (A / C) or heating to the passenger compartment. In addition, the refrigerant blends provide improved performance under heating mode conditions compared to HFO-1234yf, particularly heating capacity higher than HFO-1234yf alone, at least 15% higher than HFO-1234yf alone, or more preferably at least 20% higher than HFO-1234yf alone, and a COP for heating at least the same as or higher than HFO-1234yf alone. The COP for heating is preferably at least 2% higher than HFO-1234yf alone, and more preferably at least 3% higher than HFO-1234yf alone.

[0171] In one embodiment, a method of servicing a cooling and heating system of an electric vehicle is provided. The method includes removing all of the used refrigerant from the system and filling the system with a composition comprising a refrigerant blend consisting essentially of HFO-1234yf, HFC-32, and HFC-152a. Due to fractionation that can occur while operating a refrigerant with a temperature glide, refrigerant leaks can result in a change in the composition of the composition remaining in the heating and cooling system. This change in composition makes it difficult to determine the composition remaining in the system. Therefore, when the performance of the system is degraded, it is necessary to remove all of the refrigerant present in the cooling and heating system and refill the system with a fresh refrigerant blend having an optimized refrigerant blend composition.

[0172] In one embodiment, provided is the use of any of the foregoing compositions comprising a refrigerant blend as a heat transfer fluid in a system for heating and cooling the passenger compartment of an electric vehicle. This use of the composition of the present invention is described in detail in the foregoing description and demonstrated in the following examples.

[0173] In another embodiment, provided is the use of a composition comprising a refrigerant blend, comprising from about 78 weight percent HFO-1234yf, about 8 weight percent HFC-32, and about 14 weight percent HFC-152a; or comprising from about 72 weight percent HFO-1234yf, about 8 weight percent HFC-32, and about 20 weight percent HFC-152a being essentially for use as a heat transfer fluid in a system for heating and cooling the passenger compartment of an electric vehicle.

[0174] In one embodiment, a method is provided for reducing temperature glide in a heat exchanger operating with a refrigerant blend composition consisting essentially of HFC-32 and HFO-1234yf, comprising adding HFC-152a to the refrigerant blend composition, the composition comprising at least about 70% by weight of HFC-1234yf. The amount of HFC-152a added may vary depending on the requirements of the system in which the composition is used. In some embodiments, HFC-152a is added in an amount of about 10 to 24 weight percent, preferably about 14 to 24 weight percent, based on the weight percent of the total refrigerant blend composition resulting from the addition of HFC-152a. In some embodiments, the temperature glide in the heat exchanger may be reduced by less than 4 K, less than 3 K, less than 2.5 K, or even less than 2.0 K (e.g., a glide in the range of from greater than 0 K to less than about 2.0 K).

[0175] 6 is a contour plot showing the average temperature glide for compositions containing HFO-1234yf, HFC-32, and HFC-152a. The x-axis corresponds to the composition without HFC-152a. It can be seen that as HFC-152a is added to the composition, the average temperature glide decreases.

[0176] In other embodiments, the compositions are intended to replace traditional high GWP refrigerants in refrigeration, air conditioning, and heat pump applications, and it is desirable for the refrigerant compositions to exhibit a low GWP and similar or improved refrigerant properties compared to the traditional refrigerants.

[0177] In some embodiments, the compositions disclosed herein may be used in stationary systems such as refrigeration, air conditioning and heat pump systems. The compositions of the present invention may serve as replacements for traditional refrigerants with much higher GWP, particularly refrigerants such as R-22, R-404A, R-410A, R-407A, R-407C, or R-407F. Stationary systems may include supermarket refrigerated cases, supermarket freezer cases, chillers that provide air conditioning for large buildings such as apartments, office buildings, hospitals, and / or school buildings, residential air conditioners, residential heat pumps for heating or cooling air or for heating water or other heat transfer fluids, or residential refrigerators or freezers.

[0178] In one embodiment, disclosed herein is a stationary refrigeration, air conditioning, or heat pump system containing a refrigerant consisting essentially of about 70-78 weight percent HFO-1234yf, about 6-8 weight percent HFC-32, and about 14-24 weight percent HFC-152a.

[0179] In another embodiment, disclosed herein is a method of replacing a first refrigerant selected from R-404A, R-507A, R-507B, R-410A, R-407A, R-407C, or R-407F comprising removing at least a portion of the first refrigerant and charging a second refrigerant consisting essentially of about 70-78 weight percent HFO-1234yf, about 6-8 weight percent HFC-32, and about 14-24 weight percent HFC-152a.

[0180] In another embodiment, disclosed herein is a method for replacing a first refrigerant selected from R-513A, R-448A, R-448B, R-449A, R-452A, R-454A, R-454B, R-454C, R-466A, R-1234yf, or R-1234ze comprising removing at least a portion of the first refrigerant and charging with a second refrigerant consisting essentially of about 70-78 weight percent HFO-1234yf, about 6-8 weight percent HFC-32, and about 14-24 weight percent HFC-152a.

[0181] The following examples are provided to illustrate certain aspects of the invention and are not intended to limit the scope of the appended claims. EXAMPLES

[0182] Example 1 Comparison of thermodynamic modeling of heat pump system heating modes: HFO-1234yf / HFC-32 / HFC-152a.

[0183] A thermodynamic modeling program was used to model the expected performance of HFO-1234yf / HFC-32 / HFC-152a blends compared to HFO-1234yf. Component physical properties were taken from NIST REFPROP Version 10. In the table, suction pressure = compressor suction pressure, discharge pressure = compressor discharge pressure, discharge temperature = compressor discharge temperature, average glide = average of temperature glide for heat exchanger #1 and heat exchanger #2, heating cap = volumetric heating capacity.

[0184] The model conditions used for the heating mode were: Heat exchanger #2 was varied in 20°C increments.

[0185] [Table 3]

[0186] [Table 4]

[0187] [Table 5]

[0188] [Table 6]

[0189] Modeling results show that the refrigerant blends of the present invention containing HFO-1234yf, HFC-32, and HFC-152a provide advantages over pure HFO-1234yf. At a refrigerant temperature of -30°C, HFO-1234yf has a compressor suction pressure below atmospheric pressure and the system operates under vacuum. If a leak occurs, air and moisture can be drawn into the system. Thus, HFO-1234yf is limited to use as a heat pump fluid down to -20°C without an upgraded system design. The refrigerant blends of the present invention perform as desired at lower temperatures than HFO-1234yf alone.

[0190] Blends of HFO-1234yf, HFC-32, and HFC-152a have also been shown to have significantly higher volumetric heating capacities than HFO-1234yf. Many of the currently claimed refrigerant blends have 20% or more volumetric heating capacities compared to HFO-1234yf alone, and also have higher COPs than HFO-1234yf alone. The improved heating capacity of the inventive blends indicates that the new fluids can be easily used to provide adequate heat to the passenger compartment. Furthermore, the resulting inventive blends generally have similar compressor discharge ratios to pure HFO-1234yf over the operating range of the heat pump.

[0191] The above data demonstrates that refrigerant blends containing HFO-1234yf provide performance with low average temperature glide that is less than 4 K, less than 3 K, less than 2.5 K, or even less than 2.0 K, depending on the exact conditions. The refrigerant blends of the present invention often provide a lower average temperature glide than comparative compositions from the prior art.

[0192] Example 2 Cooling mode: HFO-1234yf / HFC-32 / HFC-152a Comparison of thermodynamic modelling of heat pump systems. A thermodynamic modeling program was used to model the expected performance of HFO-1234yf / HFC-32 / HFC-152a blends compared to HFO-1234yf and comparative compositions. Component physical properties were taken from NIST REFPROP version 10. In the table, Suction Pressure = Compressor Suction Pressure. Discharge Pressure = Compressor Discharge Pressure. Discharge Temperature = Compressor Discharge Temperature; Average Glide = Average of Temperature Glide for Heat Exchanger #1 and Heat Exchanger #2. Cooling Cap = Volumetric Cooling Capacity where Heat Exchanger #2 was varied in 10°C increments.

[0193] [Table 7]

[0194] [Table 8]

[0195] [Table 9]

[0196] [Table 10]

[0197] For a heat pump fluid to be a viable candidate, it must also perform well in cooling mode, i.e., provide adequate cooling when ambient temperatures are high. Modeling results show that refrigerant blends containing HFO-1234yf provide equivalent or improved cooling benefits over pure HFO-1234yf in the cooling range of average refrigerant temperatures from about 20°C to 40°C.

[0198] Refrigerant blends containing HFO-1234yf, HFC-32, and HFC-152a offer advantages over pure HFO-1234yf in terms of improved cooling capacity, in some cases 20% or more higher than HFO-1234yf alone. The comparable or improved cooling capacity of the blends of the present invention indicates that the new fluids can be readily used to provide adequate cooling (air conditioning) to passenger cabins.

[0199] Modeling indicates that refrigerant blends containing HFO-1234yf, HFC-32, and HFC-152a have similar COP or energy performance in the cooling range of about +20 to +40°C average refrigerant temperature.

[0200] In addition, the refrigerant blends containing mostly HFO-1234yf, HFC-32 and HFC-152a also exhibit a lower average temperature glide over the desired cooling range, i.e., about +20°C to +40°C, than comparative compositions from the prior art.

[0201] Example 3 Reduction in Mean Temperature Glide with the Addition of HFC-152a A thermodynamic modeling program was used to model the expected average temperature glide for blends of HFO-1234yf / HFC-32 with different amounts of added HFC-152a. Physical properties of the components were taken from NIST REFPROP version 10.

[0202] [Table 11]

[0203] The results show that the addition of HFC-152a to a composition containing HFO-1234yf and HFC-32 reduces the average temperature glide. With reference to Figure 6, note that the x-axis corresponds to 0 HFC-152a content. As the amount of HFC-152a increases, the average temperature glide decreases.

[0204] Example 4 Flammability of Blends of HFO-1234yf, HFC-32 and HFC-152a Flame Spread The WCF-LFL (worst case blend for flammability) and WCFF-LFL (worst case fraction for flammability) were determined for a refrigerant composition containing 78 weight percent HFO-1234yf (tolerance +1.0 / -1.0), 7.5 weight percent HFC-32 (tolerance +0.5 / -1.5), and 14.5 weight percent HFC-152a (tolerance +0.5 / -1.5). The WCF-LFL is the initial composition with the highest content of R-1234yf and R-152a based on manufacturing tolerances. The WCFF-LFL corresponds to the final liquid when a cylinder is filled with WCF-LFL to 15% of the maximum full cylinder at 54.4°C and allowed to leak at a temperature of -26.1°C. Both the WCF-LFL and WCFF-LFL were tested according to the ASTM E681-2009 test procedures as specified in ASHRAE Standard 34-2019 and documented in Appendix B1 of ASHRAE Standard 34-2019. Testing was performed in air at 23°C, 1 atmosphere, and 50% relative humidity.

[0205] The test vessel was a 12 liter spherical glass flask. The ignition source was a spark from a transformer secondary rated at 15 kV / 30ma with a spark duration of 0.4 seconds. An agitator was attached to the flask for vapor mixing. Mixture samples were prepared with concentrations determined gravimetrically and then confirmed by gas chromatographic analysis.

[0206] The film composition is as follows:

[0207] [Table 12]

[0208] Burning rate The maximum burning rates were measured for WCF-BV and WCFF-BV of the same compositions as above. WCF-BV is the initial composition with the highest content of R-152a and R-32 based on manufacturing tolerances. WCFF-BV corresponds to the final liquid when a cylinder is filled with WCF-BV to 15% of the maximum full cylinder at 54.4°C and allowed to leak at a temperature of -27.54°C. The method used to test the burning rate is the standard vertical tube method as shown in ISO 817, Appendix C. The apparatus for testing the burning rate is a Pyrex tube with an inner diameter of 40 mm and a length of 1.3 meters. The test is performed in dry air at 23°C and 101.3 kPa. The flame is observed and an image of the fully developed flame front is used to measure the flame front area from which the burning rate is calculated.

[0209] [Table 13]

[0210] Heat of combustion The heat of combustion for a composition containing 78 weight percent HFO-1234yf, 7.5 weight percent HFC-32, and 14.5 weight percent HFC-152a was determined for conditions of 25° C. (77° F.) and 101.3 kPa (14.7 psia). The heat of combustion is calculated from the balanced stoichiometric equations of all the component refrigerants. The heat of combustion was calculated to be 11.62 MJ / kg.

[0211] Although the invention has been described with reference to preferred embodiments, those skilled in the art will recognize that various changes can be made and equivalents can be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is not intended that the invention be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but the invention is intended to include all embodiments falling within the scope of the appended claims.

Claims

1. A composition comprising a refrigerant blend comprising about 66-80% by weight HFO-1234yf, about 1-10% by weight HFC-32, and about 10-24% by weight HFC-152a.

2. The refrigerant blend comprises: about 70% by weight HFO-1234yf, about 6% by weight HFC-32, and about 24% by weight HFC-152a; about 74% by weight HFO-1234yf, about 7% by weight HFC-32, and about 19% by weight HFC-152a; about 77% by weight HFO-1234yf, about 3% by weight HFC-32, and about 20% by weight HFC-152a; about 78% by weight HFO-1234yf, 7.5% by weight HFC-32, and about 14.5% by weight HFC-152a; about 78% by weight HFO-1234yf, about 6% by weight HFC-32, and about 16% by weight HFC-152a; about 79% by weight HFO-1234yf, about 3% by weight HFC-32, and about 18% by weight HFC-152a; about 80% by weight HFO-1234yf, about 4% by weight HFC-32, and about 16% by weight HFC-152a; about 70% by weight HFO-1234yf, about 8% by weight HFC-32, and about 22% by weight HFC-152a; or about 67% by weight HFO-1234yf, about 10% by weight HFC-32, and about 23% by weight HFC-152a; 2. The refrigerant composition of claim 1 consisting essentially of:

3. and further comprising at least one additional compound, said additional compound being a. comprising at least one compound selected from the group consisting of HCFC-244bb, HFC-245cb, HFC-254eb, CFC-12, HCFC-124, 3,3,3-trifluoropropyne, HCC-1140, HFC-1225ye, HFO-1225zc, HFC-134a, HFO-1243zf, and HCFO-1131; or b. comprising at least one compound selected from the group consisting of HFC-23, HCFC-31, HFC-41, HFC-143a, HCFC-22, HCC-40, HFC-161, HFO-1141, HCO-1140, HCFC-151a, HCC-150a, HCC-160, HCFO-1130a, HCFC-141b, HFC-143a, HCFO-1122, and HCFC-142b; or c. A combination of a) and b), 10. The composition of claim 1, wherein the total amount of said additional compounds comprises greater than 0 and less than 1 weight percent.

4. 2. The composition of claim 1, wherein the refrigerant is classified as 2L for flammability as defined by ANSI / ASHRAE Standard 34.

5. 10. The composition of claim 1, further comprising a lubricant, said lubricant being at least one selected from the group consisting of polyalkylene glycols, polyol esters, poly-α-olefins, and polyvinyl ethers.

6. 13. A system for heating and cooling a passenger compartment of an electric vehicle, comprising an evaporator, a compressor, a condenser, and an expansion device, each operatively connected to perform a vapor compression cycle, said system containing the composition of claim 1.

7. 13. A method for replacing HFO-1234yf in heating and cooling systems contained within an electric vehicle, comprising providing the composition of claim 1 as a heat transfer fluid.

8. 13. A method of servicing the heating and cooling system of an electric vehicle comprising removing all of the spent refrigerant from the system and charging the system with the composition of claim 1.

9. 13. Use of the composition according to claim 1 as a heat transfer fluid in a system for heating and cooling the passenger compartment of an electric vehicle.

10. 1. A method for reducing temperature glide in a heat exchanger operating with a refrigerant blend composition consisting essentially of HFC-32 and HFO-1234yf, comprising adding HFC-152a to said refrigerant blend composition, said composition comprising at least about 70 wt.% HFO-1234yf.

11. 11. The method of claim 10, wherein said HFC-152a is added in an amount of about 10 to 24 weight percent based on the weight percent of said total refrigerant blend composition.

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