Composition

Abstract

According to the present invention, a composition comprising the following is provided: (a) 1,1-difluoroethylene (R-1132a), (b) Difluoromethane (R-32), (c) 1,1-difluoroethane (R-152a), and (d)trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)).

Description

Technical Field

[0001] The present invention relates to a composition, particularly a refrigerant composition suitable for use as an alternative to existing refrigerants in liquid chiller systems, specifically in the thermal management systems of electric vehicles.

Background Art

[0002] The previously published documents or any recitation or discussion of background in this specification should not necessarily be construed as an admission that the document or background is part of the current state of the art or common general knowledge.

[0003] In new internal combustion engine (ICE) vehicles, comfortable heating of the passenger compartment is typically achieved by direct heat exchange between the waste heat from the internal combustion engine and the passenger air. ICE vehicles also typically include an air conditioning system, the sole function of which is to provide comfortable cooling and dehumidification of the air in the passenger compartment.

[0004] In contrast, most electric vehicles (EVs), whether pure electric or hybrid, do not have a waste heat source at a high enough temperature to provide comfortable heating of the interior air by direct heat exchange. Batteries, power electronics, and electric motors can act as heat sources in EVs, but typically produce heat at a temperature too low to be used directly for heating the interior air. In addition, a significant amount of battery energy is used for the thermal management of the battery itself. Without available high-temperature waste heat, using battery energy to provide passenger compartment heating and battery thermal management can significantly reduce the EV range in winter conditions.

[0005] To address this, most EV designs now incorporate heat pumps into their air conditioning systems, requiring a cooling cycle. This cooling cycle is needed not only for air conditioning but also to be integrated into the vehicle's "thermal management system," which works to transfer heat inside, around, or outside the vehicle as needed to simultaneously maintain passenger comfort, battery thermal conditions, and component cooling. There are two main design types for EV thermal management systems: air-to-air and fluid-to-fluid architectures (hereinafter referred to as "chiller architectures").

[0006] A typical air-to-air architecture features a heat exchanger where heat transfer occurs primarily via cross-flow, and air flows perpendicularly through one or more rows of coolant tubes.

[0007] In contrast, chiller architectures feature a cooling cycle integrated into a circuit of a heat / cold transfer fluid, such as water. The purpose of the cooling cycle is to move heat from the cold loop to the hot loop.

[0008] Propane (R-290) has been successfully tested for application in chiller systems. However, propane is a volatile organic compound (VOC) and is considered a precursor to the formation of environmentally undesirable photochemical smog. In addition, the ability of propane to operate in heat pump cycles is limited to ambient temperatures of approximately -30°C, which is typically insufficient for extremely low winter conditions.

[0009] 1,1-Difluoroethane (R-152a) has been proposed for use in chiller architectures. It is relatively inexpensive, has an acceptable global warming potential (GWP) of 124, and is efficient as an air conditioning refrigerant. However, its flammability (ASHRAE Class 2) prevents its use in direct heat exchange with indoor air, and its normal boiling point is higher than that of R-1234yf, which means its performance in heat pump mode is poor and it is inefficient for cold ambient heat pumps, as it is limited to temperatures above -15°C.

[0010] 2,3,3,3-tetrafluoropropene (R-1234yf) is currently used in automotive air conditioning systems. R-1234yf is weakly flammable (class "2L" according to ASHRAE SSPC34). This level of flammability is accepted by the automotive industry following extensive risk assessment processes, as it is considered low enough to allow for safe engineering designs to mitigate its hazards. It is desirable to identify alternative refrigerants that may offer better performance in EV thermal management applications while maintaining acceptablely low flammability, similar to that of R-1234yf.

[0011] Refrigerants such as R-454C (R-32 / R-1234yf 21.5% / 78.5%) and R-474A (R-1132(E) / R-1234yf 23% / 77%) have a GWP lower than 150 and a vapor pressure higher than that of R-1234yf. However, they are blended with R-1234yf. While R-1234yf possesses certain desirable performance characteristics, it is known to decompose rapidly in the environment at 100% molar yield to form trifluoroacetic acid (TFA). TFA is toxic and highly resistant to environmental degradation. Large-scale introduction of R-1234yf or blends containing this compound in EV systems could lead to increased TFA levels in groundwater. Therefore, there is a need for new refrigerants that produce less TFA than R-1234yf upon release into the environment. [Disclosure of the Invention]

[0012] Surprisingly, compositions of the present invention containing very low levels of R-1234yf (or preferably substantially free of R-1234yf), such as compositions in which any R-1234yf is effectively substituted by R-1234ze(E), exhibit one or more of the following, in addition to reduced TFA production: improved energy efficiency and lower flammability limits (e.g., at room temperature).

[0013] Therefore, there is a need to provide alternative refrigerants for use in EV thermal management systems, such as those employing chiller architectures, which have improved properties such as low GWP (to reduce the environmental impact of refrigerant leakage), and further possess acceptable cooling performance, flammability, and toxicity in the event of accidental release into the passenger compartment.

[0014] The present invention addresses the above and other defects / needs by providing a composition comprising 1,1-difluoroethylene (R 1132a), difluoromethane (R-32), 1,1-difluoroethane (R-152a), and trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)).

[0015] Surprisingly, the compositions of the present invention have been found to exhibit performance comparable to or better than that of propane, particularly when used in EV thermal management systems, such as those employing chiller architectures, under extreme winter conditions. Similarly, the compositions of the present invention have been found to exhibit better environmental characteristics compared to propane or R-1234yf. Surprisingly, the compositions of the present invention have also been found to exhibit a thermal glide in evaporation or condensation that is close to the typical temperature changes of heat transfer fluids (such as water, glycol, or fluorinated fluids) used in EV thermal management systems employing chiller architectures. This enables improvements in the capacity and energy efficiency of such thermal management systems.

[0016] The compositions of the present invention typically contain about 1 to about 20% by weight of R-1132a. For example, the compositions may contain about 2 to about 20% by weight of R-1132a, such as about 3 to about 20% by weight, preferably about 4 to about 18% by weight, such as about 6 to about 16% by weight, preferably 8 to 16% by weight.

[0017] The composition of the present invention may contain about 1 to about 35% by weight of R-32. Conveniently, the composition contains about 5 to about 28% by weight of R-32, such as about 2 to about 30% by weight, for example, about 7 to about 25% by weight, preferably about 10 to about 22% by weight.

[0018] R-152a may be included in the composition of the present invention in an amount of about 1 to about 50% by weight, such as about 2 to about 40% by weight, for example, about 2 or about 3 to about 30% by weight, for example, about 3 or about 4 to about 25% by weight, preferably 6 to 18% by weight, such as about 2 or about 3 to about 35% by weight.

[0019] The compositions of the present invention preferably contain about 30 to about 85% by weight of R-1234ze(E), for example, about 45 to about 70% by weight, preferably 45 to about 63% by weight, about 40 to about 75% by weight, about 35 to about 80% by weight, or about 30 to about 90% by weight.

[0020] Therefore, the present invention provides a composition comprising about 1 to about 20% by weight of R-1132a, about 1 to about 35% by weight of R-32, about 1 to about 50% by weight of R-152a, and about 30 to about 90% by weight of R-1234ze(E).

[0021] For example, the composition of the present invention may contain about 2 to about 20% by weight of R-1132a, about 2 to about 30% by weight of R-32, about 2 to about 40% by weight of R-152a, and about 30 to about 85% by weight of R-1234ze(E).

[0022] The composition of the present invention may contain about 3 to about 20% by weight of R-1132a, about 5 to about 28% by weight of R-32, about 3 to about 35% by weight of R-152a, and about 35 to about 80% by weight of R-1234ze(E).

[0023] Conveniently, the composition of the present invention comprises about 4 to about 18% by weight of R-1132a, about 7 to about 25% by weight of R-32, about 3 to about 30% by weight of R-152a, and about 40 to about 75% by weight of R-1234ze(E).

[0024] Advantageously, the compositions of the present invention comprise about 4 to about 16% by weight of R-1132a, about 10 to about 22% by weight of R-32, about 4 to about 25% by weight of R-152a, and about 45 to about 70% by weight of R-1234ze(E).

[0025] Certain preferred compositions of the present invention include, for example, about 8 to about 16% by weight of R-1132a, about 16 to about 21% by weight of R-32, about 8 to about 18% by weight of R-152a, and about 50 to 60% by weight of R-1234ze(E), such as about 6 to about 16% by weight of R-1132a, about 15 to about 22% by weight of R-32, about 7 to about 20% by weight of R-152a, and about 50 to 60% by weight of R-1234ze(E).

[0026] Typically, the weight ratio of R-152a to R-1234ze(E) in the composition of the present invention is 1:1.5 or less, such as 1:2 or 1:2.5 or less. For example, R-152a is present in the composition of the present invention in an amount such that the weight ratio of R-152a to R-1234ze(E) is about 1:2 to about 1:25, for example, about 1:2.5 to about 1:20, such as about 1:1.5 to about 1:30.

[0027] Preferably, the weight ratio of R-152a to R-1234ze(E) in the composition of the present invention is 1:3 or less, such as 1:3.1 or 1:3.2 or less. Therefore, in preferred embodiments, R-152a and R-1234ze(E) are present in the composition of the present invention in amounts such that the weight ratio of R-152a to R-1234ze(E) is about 1:3 to about 1:15, preferably about 1:3.1 to about 1:12, or 1:3.2 to 1:10. Surprisingly, the inventors have found that by including R-152a according to these ratios, it is possible to maximize the cooling benefit of R-152a in the context of the COP and volumetric cooling capacity of the composition of the present invention, while simultaneously achieving low flammability (Class 2L) of the composition, despite R-152a itself being flammable, classified as Class "2" (flammable refrigerant) according to ASHRAE Standard 34. This is particularly desirable when the composition of the present invention is used in an EV thermal management system in which there is a possibility that the refrigerant may leak into the passenger compartment.

[0028] Optionally, the composition of the present invention further comprises R-1132(E). Thus, the present invention provides a composition comprising, in particular, the above amounts of R-1132a, R-32, R-152a, R-1234ze(E), and from about 1 to about 32% by weight, such as from about 2 to about 25% by weight or from about 6 to about 24% by weight, preferably from about 9 to about 21% by weight, etc., of R-1132(E). When R-1132(E) is included in the composition of the present invention, it is also preferred that the composition contains R-1132(E) in an amount less (by weight) than R-32. Surprisingly, it has been found that the use of R-1132(E) can reduce the GWP of the composition of the present invention without impairing their performance characteristics.

[0029] The composition of the present invention may contain from 0 to about 15% by weight, preferably from 0 to about 5% by weight or from 0 to about 1% by weight, etc., of 2,3,3,3-tetrafluoropropene (R-1234yf). In one embodiment, the composition of the present invention is substantially free of R-1234yf. By including R-1234yf in these amounts, it is ensured that the total generation coefficient of TFA from the unit mass of the composition of the present invention is significantly lower than that of the same amount of other refrigerants formulated using R-1234yf, and at the same time, optionally, the composition of the present invention can utilize the advantageous properties of R-1234yf.

[0030] Any of the above compositions may further contain carbon dioxide (CO2). The presence of CO2 generally tends to increase the outlet temperature of the compressor and the temperature glide (which may be undesirable), but the inventors have surprisingly found that by including CO2 in the composition of the present invention, it is possible to formulate a low GWP blend having a flammability such that both WCF and WCFF are classified as "2L" under the ASHRAE 34 evaluation process.

[0031] When present, CO2 is typically included in the composition of the present invention in an amount from about 1 or about 2 to about 18% by weight, such as from about 2 to about 16% by weight, etc., from about 1 to about 20% by weight.

[0032] When CO2 is present in the composition of the present invention, R-1132a may be included in the composition in an amount of about 1 to about 20% by weight, such as about 1 or about 2 to about 18% by weight, for example, about 2 to about 16% by weight.

[0033] Advantageously, R-1132a and CO2 are present in the composition of the present invention in a total amount of about 2 to about 25% by weight, such as about 3 or about 4 to about 20% by weight, preferably about 5 to about 18% by weight or about 6 to about 18% by weight.

[0034] Therefore, the present invention provides a composition comprising a total amount of R-1132a and CO2 in about 2 to about 25% by weight, R-32 in about 1 to about 35% by weight, R-152a in about 1 to about 50% by weight, and R-1234ze(E) in about 30 to about 90% by weight.

[0035] For example, the composition of the present invention may contain a total amount of about 3 to about 20% by weight of R-1132a and CO2, about 2 to about 30% by weight of R-32, about 2 to about 40% by weight of R-152a, and about 30 to about 85% by weight of R-1234ze(E).

[0036] The composition of the present invention may contain a total amount of R-1132a and CO2 in about 5 to about 20% by weight, about 5 to about 28% by weight of R-32, about 3 to about 35% by weight of R-152a, and about 35 to about 80% by weight of R-1234ze(E).

[0037] Conveniently, the composition of the present invention comprises a total amount of about 5 to about 18% by weight of R-1132a and CO2, about 7 to about 25% by weight of R-32, about 3 to about 30% by weight of R-152a, and about 40 to about 75% by weight of R-1234ze(E).

[0038] Advantageously, the compositions of the present invention comprise a total amount of about 6 to about 18% by weight of R-1132a and CO2, about 10 to about 23% by weight of R-32, about 4 to about 25% by weight of R-152a, and about 45 to about 70% by weight of R-1234ze(E).

[0039] Certain preferred compositions of the present invention include a total amount of about 4 to about 16% by weight of CO2 and R-1132a, about 15 to about 22% by weight of R-32, about 11 to about 22% by weight of R-152a, and about 50 to about 65% by weight of R-1234ze(E), preferably a total amount of about 6 to about 14% by weight of CO2 and R-1132a, about 16 to about 21% by weight of R-32, about 12 to about 20% by weight of R-152a, and about 50 to 60% by weight of R-1234ze(E).

[0040] Such compounds of the present invention may contain about 3 to about 7 wt% CO2, about 3 to about 7 wt% R-1132a, about 10 to about 22 wt% R-32, about 8 to about 16 wt% R-152a, and about 50 to about 60 wt% R-1234ze(E).

[0041] To avoid any ambiguity, the disclosure of the weight ratio of R-152a to R-1234ze(E) and its effects are understood to also apply to compositions containing CO2 and other compositions described herein.

[0042] Any of the above compositions may further contain one or more compounds selected from the group consisting of 1,1,1,2-tetrafluoroethane (R-134a), butane (R-600), isobutane (R-600a), propane (R-290), octafluoropropane (R-218), 1,1,1,2,3,3,3-heptafluoropropane (R-227ea), trifluoroethylene (R-1123), fluoromethane (R-41), 3,3,3-trifluoropropene (R-1243zf), and / or fluoroethane (R-161), and mixtures thereof. Typically, the compositions of the present invention contain about 1 to about 15% by weight of one or more compounds, such as about 1 to about 10% by weight, for example, about 1 to about 5% by weight.

[0043] In embodiments, the composition may essentially consist of the components described. The term “essentially consisting of” means that the composition of the present invention is substantially free of other components, in particular further (hydro)(fluoro) compounds (e.g., (hydro)(fluoro)alkanes or (hydro)(fluoro)alkenes) known to be used in heat transfer compositions. The term “consisting of” is included in the meaning of “essentially consisting of.”

[0044] Preferably, the compositions of the present invention are substantially free of trifluoroethylene (R-1123). Surprisingly, such compositions have been found to improve lifespan and chemical stability when used in EV thermal management systems.

[0045] In the embodiments, the compositions of the present invention substantially contain no components having heat transfer properties other than the specified components. For example, the compositions of the present invention may substantially contain no other hydrofluorocarbon compounds.

[0046] "Substantially absent" and "substantially not contained" include the meaning that the composition of the present invention contains the described components in an amount of 0.5% by weight or less, preferably 0.4%, 0.3%, 0.2%, or 0.1% or less, based on the total weight of the composition.

[0047] In one embodiment, the composition is substantially free of trifluoroiodomethane (CF3I).

[0048] All chemical substances described herein are commercially available. For example, fluorochemicals may be obtained from Apollo Scientific (UK), and carbon dioxide may be obtained from liquefied gas suppliers such as Linde AG.

[0049] When used herein, all percentages referred to in the compositions herein, including the claims, are by weight based on the total weight of the composition unless otherwise specified.

[0050] The term "approximately," when used in relation to the numerical value of a component's weight percentage, includes the meaning of ±0.5% by weight, for example, ±0.1% by weight.

[0051] To avoid any doubt, it should be understood that the upper and lower limits described herein for the range of amounts of components in the compositions of the present invention may be replaced in any way, as long as the resulting range falls within the broadest range of the present invention.

[0052] The composition of the present invention has an ozone depletion potential of zero.

[0053] Typically, the compositions of the present invention have a global warming potential (GWP) of less than 300. Preferably, the compositions of the present invention have a GWP of less than 250, for example, less than 175, preferably less than 150, and less than 200.

[0054] Typically, the compositions of the present invention have a reduced flammability hazard compared to R-1132a and R-1132(E) alone.

[0055] Flammability may be determined in accordance with ASHRAE Standard 34, which incorporates ASTM Standard E-681, using the test methodology set forth in Appendix 34 of 2004, which is incorporated herein by reference in its entirety.

[0056] In one embodiment, the composition has one or more of the following characteristics compared to R-1132a and R-1132(E) alone: ​​(a) a higher "lower flammability limit" (LFL), (b) a higher ignition energy (sometimes referred to as spontaneous ignition energy or pyrolysis), or (c) a lower flame velocity. Preferably, the composition of the present invention is less flammable than R-1132a and R-1132(E) in one or more of the following: lower flammability limit at 23°C, lower flammability limit at 60°C, width of the flammability range at 23°C or 60°C, spontaneous ignition temperature (pyrolysis temperature), minimum ignition energy in dry air, or flame velocity. The flammability limit is determined according to the method specified in ASHRAE-34, and the spontaneous ignition temperature is determined in a 500 ml glass flask according to the method of ASTM E659-78.

[0057] Preferably, compositions of the present invention containing very low levels of R-1234yf (or preferably substantially R-1234yf-free) have a higher LFL than compositions containing R-1234yf or a significant amount of R-1234yf, such as compositions containing a high amount of R-1234yf compared to R-1234ze(E). For example, compositions of the present invention containing very low levels of R-1234yf (preferably substantially R-1234yf-free) have a higher LFL than equivalent compositions in which R-1234ze(E) in the composition of the present invention is effectively substituted with R-1234yf.

[0058] In one embodiment, the composition of the present invention has a flammability that can be classified as 2 or 2L according to the ASHRAE Standard 34 classification system, which represents a slightly flammable fluid (class 2L) or a flammable fluid (class 2) with a flame velocity of less than 10 cm / sec.

[0059] The flammability of refrigerant compositions is classified according to ASHRAE SSPC34 and ISO 817 through a complex evaluation process. Two compositions are considered: "Worst-Called Composition" (WCF) and "Worst-Called Composition for Flammability" (WCFF). WCF is the most flammable composition in the blend, with a certain maximum permissible level, according to the manufacturing tolerances specified by the blend designer during the application process. WCFF is the most flammable composition that can occur during refrigerant vapor leakage from a cylinder or system at any temperature between -40°C and +60°C.

[0060] Typically, at least the WCF of the compositions of the present invention has a flammability classified as "2L" by the ASHRAE-34 evaluation process, and certain compositions of the present invention, as described above, have both WCF and WCFF having a flammability classified as "2L" by the ASHRAE-34 evaluation process.

[0061] The compositions of the present invention exhibit an unexpected combination of low flammability / non-flammability, low GWP, improved lubricant miscibility, and improved cooling performance characteristics. Some of these cooling performance characteristics are described in more detail below.

[0062] The compositions of the present invention typically have a coefficient of performance (COP) of 15% or less of that of propane (cooling and / or heating COP). Advantageously, the compositions of the present invention have a COP of approximately 7% or less of that of propane, for example, approximately 5%, preferably equal to or greater than that of propane, or approximately 10% or less of that of propane.

[0063] Typically, the compositions of the present invention have a volumetric cooling capacity (whether cooling or heating capacity) of about 15% or less of the volumetric cooling capacity of propane. Conveniently, the compositions of the present invention have a volumetric cooling capacity of about 10% or less of the volumetric cooling capacity of propane, for example, about 5% or less. More preferably, the volumetric cooling capacity is equal to or greater than the volumetric cooling capacity of propane.

[0064] The compositions of the present invention typically exhibit a temperature glide in the evaporator or condenser of about 25K to about 3K, preferably about 20K to about 5K, and more preferably about 15K to about 5K. Such a temperature glide is particularly suitable for thermal management systems using chiller architectures such as those using water / ethylene glycol or triacetin / carbon dioxide.

[0065] The compositions of the present invention typically have a foaming point at atmospheric pressure of less than about -35°C. Preferably, the compositions have a foaming point at atmospheric pressure of less than about -42°C, and more preferably less than about -50°C. Alternatively, in addition, the compositions of the present invention preferably have a vapor pressure greater than 1 bar at -40°C.

[0066] Conveniently, the composition of the present invention has a combustion rate of less than approximately 10 cm / second, as measured by the ASHRAE Standard 34.

[0067] Conveniently, the total generation coefficient of TFA from a unit mass of the composition of the present invention is less than the total generation coefficient of R-1234yf of an equivalent mass, such as 10% or less, preferably 5% or less, more preferably 2% or less, or even 1% or less.

[0068] The compositions of the present invention are typically suitable for use in existing equipment designs and are compatible with all classes of lubricants currently in use with established HFC refrigerants. They may be optionally stabilized or compatible with mineral oils (e.g., lubricants) by the use of appropriate additives such as polyol esters (POEs), for example, POEs having a viscosity of about 7–32 cSt at about 40°C.

[0069] Therefore, in one embodiment, the composition of the present invention is combined with a lubricant, particularly when used in a heat transfer device.

[0070] Conveniently, the lubricant is selected from the group consisting of mineral oil, silicone oil, polyalkylbenzene (PAB), polyol ester (POE), polyalkylene glycol (PAG, also known as polyether), polyalkylene glycol ester (PAG ester), polyvinyl ether (PVE), poly(alpha-olefin), and combinations thereof. PAG and POE are currently preferred lubricants for the compositions of the present invention.

[0071] Advantageously, the lubricant further comprises a stabilizer. In a similar embodiment, the composition of the present invention may be combined with a stabilizer.

[0072] Preferably, the stabilizer is selected from the group consisting of diene compounds, phosphates, phenol compounds (such as 2,6-di-tert-butyl-4-methylphenol), epoxides, and mixtures thereof.

[0073] Conveniently, the composition of the present invention may be combined with a flame retardant.

[0074] Advantageously, the flame retardant is selected from the group consisting of tri-(2-chloroethyl)-phosphate, (chloropropyl)-phosphate, tri-(2,3-dibromopropyl)-phosphate, tri-(1,3-dichloropropyl)-phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, polyvinyl chloride, fluorinated iodocarbon, fluorinated bromocarbon, trifluoroiodomethane, perfluoroalkylamine, bromo-fluoroalkylamine, and mixtures thereof.

[0075] In one aspect of the present invention, a liquid chiller system is provided which includes a refrigerant, the refrigerant being a composition of the present invention, and further includes at least one counterflow heat exchanger for exchanging heat between the refrigerant and the liquid.

[0076] Such chiller architectures can be used in combination with air-to-air architectures. For example, a chiller architecture can be used to manage the temperature of an EV's battery, while an air-to-air architecture can be used for cabin air conditioning.

[0077] Typically, the liquids used in the liquid chiller systems disclosed above are selected from water, brine, glycol, synthetic hydrocarbon fluids, silicone-based fluids, or fully or partially fluorinated organic fluids (e.g., fluorinated ethers or ketones), fluid blends of freezing point lowering additives or viscosity lowering additives (triacetin, diacetin, acetone, and / or carbon dioxide, e.g., acetone combined with carbon dioxide), and mixtures thereof. Preferably, the liquid chiller system is a water chiller system, a water / glycol chiller system, or a chiller system using a fully or partially fluorinated organic fluid.

[0078] Counterflow heat exchangers are configured such that the refrigerant and liquid flow in opposite directions (including quasi-reverse flow) to each other as they pass through the heat exchanger. In such configurations, the refrigerant condensation temperature only needs to be higher than the temperature of the coolant entering the condenser, and the maximum refrigerant evaporation temperature only needs to be lower than the heat source inlet temperature. For this reason, temperature glide may allow the refrigerant to operate in a lower temperature range than a fluid without glide, resulting in improved relative capacity and energy efficiency.

[0079] In related aspects of the present invention, the use of the compositions of the present invention as refrigerants in a liquid chiller system (such as those disclosed above) is provided, preferably the liquid chiller system being incorporated into or being a thermal management system of an electric vehicle. Typically, the liquid chiller system is a liquid chiller system adapted for heating and / or cooling the battery and / or passenger compartment of an electric vehicle. For example, the liquid chiller system may be adapted for cooling and / or heating the passenger compartment of an electric vehicle, or it may be adapted for cooling the battery of an electric vehicle. Alternatively, the liquid chiller system may be adapted for cooling other potentially useful sources of waste heat, such as power electronics, instrument displays, or brake systems.

[0080] The thermal management systems for electric vehicles typically include heat pumps and / or air conditioning systems.

[0081] The present invention also provides the use of the compositions of the present invention as substitutes for existing refrigerants (such as in the liquid chiller systems disclosed above), preferably the existing refrigerant being propane and / or R-1234yf, or comprising the same, for example, the existing refrigerant being propane or R-1234yf.

[0082] A method for modifying a heat transfer device is also provided, comprising the steps of removing an existing heat transfer composition and introducing the composition of the present invention. Conveniently, this heat transfer device is a thermal management system for an electric vehicle. Advantageously, the existing heat transfer composition is propane (R-290) or 2,3,3,3-tetrafluoropropene (R-1234yf).

[0083] In a related aspect of the present invention, a thermal management system for an electric vehicle is provided, which comprises the liquid chiller system disclosed above.

[0084] In another aspect of the present invention, a heat transfer device is provided which includes a refrigerant, the refrigerant being a composition of the present invention, and further includes a heat sink fluid or heat source, and at least one counterflow heat exchanger for exchanging heat between the refrigerant and the heat sink fluid or heat source. The present invention also provides the use of the composition of the present invention in such a heat transfer device described herein.

[0085] A counterflow heat exchanger is configured such that the refrigerant and liquid flow in opposite directions (including quasi-reverse flow) to each other as they pass through the heat exchanger.

[0086] Such a heat transfer device may include a static cooling system, an air conditioning system, or a heat pump.

[0087] In such heat transfer devices, the heat sink fluid or heat source may be selected from water, brine, glycol, synthetic hydrocarbon fluid, silicone-based fluid or fully or partially fluorinated organic fluid (e.g., fluorinated ether or ketone), fluid blends of freezing point lowering additives or viscosity lowering additives (triacetin, diacetin, acetone, and / or carbon dioxide, e.g., acetone combined with carbon dioxide), and mixtures thereof.

[0088] In another embodiment, the use of the compositions of the present invention in a thermal management system for an electric vehicle is provided, the thermal management system comprising an air-to-air architecture. Surprisingly, it is found here that these compositions can be used in air-to-air designs with little or no modification to existing design architectures. In this embodiment, the thermal management system typically comprises a heat pump and / or air conditioning system, preferably a heat pump adapted to provide air conditioning. The EV thermal management system in this embodiment may also incorporate chiller loops for cooling heat-generating components of the electric vehicle, such as the battery, power electronics, and / or electric motor.

[0089] Furthermore, in this embodiment, as hot air passes over the rows of refrigerant tubes in the evaporator in a (nearly) perpendicular cross flow, the air is cooled while the refrigerant evaporates inside the evaporator tubes. Similarly, heat is released by condensing the refrigerant inside the tubes by flowing outside air over the condenser tubes in a cross flow. For heat exchange to occur in the condenser of the refrigerant circuit, the minimum refrigerant condensation temperature must be higher than the temperature of the air leaving the condenser. Similarly, in the evaporator, the maximum refrigerant evaporation temperature must be lower than the temperature of the air leaving the evaporator.

[0090] When a refrigerant undergoes thermal glide during evaporation or condensation, a cross-flow configuration tends to reduce the effective temperature difference between the air and the refrigerant compared to a single-component refrigerant without glide, thus decreasing the efficiency of the heat exchanger. This has the effect of making the refrigerant's performance unfavorable compared to a fluid without glide. For this reason, it is generally desirable to keep the refrigerant glide low when using a cross-flow heat exchanger.

[0091] Another aspect of the present invention provides a method for generating cooling, comprising evaporating the composition of the present invention near an object to be cooled. Preferably, this method is for generating cooling in an electric vehicle.

[0092] A further aspect of the present invention provides a method for generating heat, comprising condensing the composition of the present invention near an object to be heated. Preferably, this method is for generating heat in an electric vehicle.

[0093] The compositions of the present invention may also be prepared simply by mixing R-1132a, R-32, R-152a, and R-1234ze(E) (and optional components such as R-1132(E), R-744, lubricants, stabilizers, or additional flame retardants) in desired proportions. Thus, the compositions can be added to a heat transfer device (or used in any other way as defined herein).

[0094] Next, the present invention will be described with reference to the following non-limiting embodiments. [Examples]

[0095] A thermodynamic properties model was constructed using the NIST REFPROP9.1 software package. Using this model, the cooling cycle performance of an idealized vapor compression cycle with known heat exchanger size was modeled, with propane (R-290) as the reference fluid.

[0096] The heat exchanger was modeled to be arranged in reverse flow. The required heat exchanger size was first determined based on the use of propane as the refrigerant, by specifying the temperature changes of the heat source and heat sink fluids and the minimum temperature difference between the refrigerant and the external fluid. The performance of the selected refrigerant blend of the present invention was then evaluated by adjusting the condensation and evaporation pressures of the refrigerant so that the same cooling or heating capacity was achieved in a heat exchanger of the same size. This approach is known as the "UA Cycle" as described in Chapter 3 of "Vapor Compression Heat Pumps With Refrigerant Mixtures", R. Radermacher, Y. Hwang, pub. CRC Press (Taylor & Francis) 2005, which is incorporated herein by reference.

[0097] The following cycle modeling conditions were assumed for the air conditioning cycle. [Table 1]

[0098] The table below shows the results for propane (R-290) under these conditions. [Table 2]

[0099] The results for the selected compositions in the air conditioning mode are shown in Tables 1 to 28.

[0100] Next, the performance of the selected composition of the present invention in heat pump mode was evaluated using propane as the reference refrigerant. The following cycle modeling conditions were used. [Table 3]

[0101] The following table shows the results for propane (R-290) under these conditions. [Table 4]

[0102] The results for the selected compositions in heat pump mode are shown in Tables 29-58.

[0103] Surprisingly, the compositions of the present invention have been found to have a thermal glide in evaporation or condensation that is close to the typical temperature changes of heat transfer fluids (such as water, glycol, or fluorinated fluids) used in EV thermal management systems employing chiller architectures. This enables improvements in the performance and energy efficiency of such thermal management systems.

[0104] The table shows that it is possible to formulate compositions whose volume is at least 10% of the volume of propane, and can exceed the volume of propane. This means that compressor designs for propane (or other refrigerants of equivalent performance) may be easily adapted for use with the fluids of the present invention. These tables also show that it is possible to increase the COP in both heating and cooling modes compared to propane. For this reason, the compositions of the present invention provide excellent energy efficiency, which is beneficial for the EV range. Finally, it can be seen that the operating pressure of the compositions of the present invention is equivalent to that of propane. This is expected to simplify the adaptation of existing automotive parts.

[0105] The data in the table surprisingly shows that using R-152a in the composition of the present invention makes it possible to increase both capacity and COP while reducing temperature glide. [Table 5] [Table 6] [Table 7] [Table 8] [Table 9] [Table 10] [Table 11] [Table 12] [Table 13] [Table 14] [Table 15] [Table 16] [Table 17] [Table 18] [Table 19] [Table 20] Table 21 Table 22 Table 23 Table 24 Table 25 Table 26 Table 27 Table 28 Table 29 Table 30 Table 31 Table 32 Table 33 Table 34 Table 35 Table 36 Table 37 Table 38 Table 39 Table 40 Table 41 Table 42 Table 43 Table 44 Table 45 Table 46 Table 47 Table 48 Table 49 Table 50 Table 51 Table 52 Table 53 Table 54 Table 55 Table 56 Table 57 Table 58 Table 59 Table 60 Table 61 Table 62

Claims

1. A composition, (a) 1,1-difluoroethylene (R-1132a), (b) Difluoromethane (R-32), (c) 1,1-difluoroethane (R-152a), and (d) A composition comprising trans-1,3,3,3-tetrafluoropropene (R-1234ze(E)).

2. The composition according to claim 1, comprising approximately 1 to approximately 20% by weight of R-1132a, for example, approximately 3 to approximately 20% by weight, preferably approximately 4 to approximately 16% by weight, or approximately 4 to approximately 18% by weight.

3. The composition according to claim 1 or 2, comprising about 1 to about 35% by weight of R-32, such as about 5 to about 28% by weight, for example, about 7 to about 25% by weight, preferably about 10 to about 22% by weight.

4. A composition according to any one of the prior claims, comprising about 1 to about 50% by weight of R-152a, such as about 3 to about 35% by weight, for example, about 2 to about 40% by weight, for example, about 3 to about 30% by weight, preferably about 4 to about 25% by weight.

5. A composition according to any one of the prior claims, comprising about 30 to about 85% by weight of R-1234ze(E), for example, about 40 to about 75% by weight, preferably about 45 to about 70%, such as about 35 to about 80%, such as about 30 to about 90% by weight.

6. The composition according to any one of the prior claims, wherein the composition comprises about 2 to about 20% by weight of R-1132a, about 2 to about 30% by weight of R-32, about 2 to about 40% by weight of R-152a, and about 30 to about 85% by weight of R-1234ze(E), for example, about 3 to about 20% by weight of R-1132a, about 5 to about 28% by weight of R-32, about 3 to about 35% by weight of R-152a, and about 35 to about 80% by weight of R-1234ze(E), or about 1 to about 20% by weight of R-1132a, about 1 to about 35% by weight of R-32, about 1 to about 50% by weight of R-152a, and about 30 to about 90% by weight of R-1234ze(E).

7. The composition according to any one of the prior claims, wherein the composition comprises about 6 to about 16% by weight of R-1132a, about 15 to about 22% by weight of R-32, about 7 to about 20% by weight of R-152a, and about 50 to 60% by weight of R-1234ze(E), such as about 8 to about 16% by weight of R-1132a, about 16 to about 21% by weight of R-32, about 8 to about 18% by weight of R-152a, and about 50 to 60% by weight of R-1234ze(E).

8. The composition according to any one of the prior claims, wherein the weight ratio of R-152a to R-1234ze(E) is 1:2 or less, for example, 1:2.5 or less, preferably 1:3 or less, and so on, 1:1.5 or less.

9. The composition according to any one of the prior claims, wherein R-152a is present in the composition of the present invention in an amount such that the weight ratio of R-152a to R-1234ze(E) is about 1:3 to about 1:15, preferably about 1:3.1 to about 1:12, or 1:3.2 to 1:

10.

10. The composition according to any one of the prior claims, further comprising R-1132(E), for example, R-1132(E) present in an amount of about 1 to about 32% by weight, such as about 1 to about 28% by weight, for example, about 2 to about 25% by weight or about 6 to about 24% by weight, preferably about 9 to about 21% by weight.

11. The composition according to claim 10, wherein R-1132(E) is present in an amount less than the amount of R-32 by weight.

12. The composition according to any one of the prior claims, wherein the composition comprises 0 to 15% by weight of 2,3,3,3-tetrafluoropropene (R-1234yf), such as 0 to about 10% by weight, and optionally the composition is substantially free of R-1234yf.

13. The composition contains carbon dioxide (CO2). ２ The composition according to any one of the prior claims, further comprising:

14. The aforementioned CO ２ The composition according to claim 13, wherein the substance is present in an amount of about 2 to about 18% by weight, for example, about 2 to about 16% by weight, or about 1 to about 18% by weight, or about 1 to about 20% by weight.

15. The aforementioned R-1132a and the aforementioned CO ２ The composition according to claim 13 or 14, wherein the total amount is about 2 to about 25% by weight, preferably about 3 or about 4 to about 20% by weight, preferably about 5 to about 18% by weight or about 6 to about 18% by weight.

16. The composition contains a total amount of R-1132a and CO in an amount of about 2 to about 25% by weight. ２ The composition comprises approximately 1 to approximately 35% by weight of R-32, approximately 1 to approximately 50% by weight of R-152a, and approximately 30 to approximately 90% by weight of R-1234ze(E), for example, the composition comprises approximately 3 to approximately 20% by weight of R-1132a and CO ２ The composition according to any one of claims 13 to 15, comprising, for example, about 2 to about 30% by weight of R-32, about 2 to about 40% by weight of R-152a, and about 30 to about 85% by weight of R-1234ze(E), wherein the composition comprises a total amount of about 5 to about 20% by weight of R-1132a and CO2, about 5 to about 28% by weight of R-32, about 3 to about 35% by weight of R-152a, and about 35 to about 80% by weight of R-1234ze(E).

17. Approximately 6 to 18% by weight of R-1132a and CO ２ A composition containing approximately 15 to 22% by weight of R-32, approximately 10 to 18% by weight of R-152a, and approximately 50 to 60% by weight of R-1234ze(E), etc., with a total amount of approximately 4 to 16% by weight of CO2. ２ The composition according to any one of claims 13 to 16, comprising R-1132a, about 15 to about 22% by weight of R-32, about 11 to about 22% by weight of R-152a, and about 50 to 65% by weight of R-1234ze(E).

18. A composition according to any one of the prior claims, which essentially consists of the components of the description.

19. The composition is the composition according to any one of the prior claims, wherein the global warming potential (GWP) is less than 250, for example less than 175, preferably less than 150, and less than 200.

20. The composition according to any one of the prior claims, wherein the composition is less flammable than R-1132a and / or R-1132(E) alone.

21. The composition is superior to R-1132a and / or R-1132(E) alone. a. Higher flammability limit, b. Higher ignition energy, and / or c. Having a lower flame velocity, Preferably, the composition according to claim 20, wherein the composition is non-flammable.

22. The composition is the composition according to any one of the prior claims, wherein the coefficient of performance (COP) is within approximately 7% of the coefficient of performance of propane, for example, within approximately 5%, and within approximately 10%, and preferably the COP is equal to or greater than the coefficient of performance of propane.

23. The composition according to any one of the prior claims, wherein the volumetric cooling capacity is within about 10% of the volumetric cooling capacity of propane, for example, within about 5%, and within about 15%, and preferably the volumetric cooling capacity is equal to or greater than that of propane.

24. The composition according to any one of the prior claims, wherein the temperature glide in the evaporator or condenser is about 20K to about 5K, preferably about 15K to about 5K.

25. The composition is the composition according to any one of the prior claims, wherein the combustion rate is less than about 10 cm / second as measured by ASHRAE Standard 34.

26. The composition according to any one of the prior claims, wherein the foaming point at atmospheric pressure is less than about -42°C, preferably less than about -50°C.

27. The composition according to any one of the prior claims, wherein the total generation coefficient of TFA from a unit mass of the composition is 15% or less, for example, 2% or less, preferably 1% or less, which is less than the total generation coefficient of R-1234yf of equivalent mass.

28. A composition comprising a lubricant and a composition according to any one of the prior claims, wherein the lubricant is preferably selected from mineral oil, silicone oil, polyalkylbenzene (PAB), polyol ester (POE), polyalkylene glycol (PAG), polyalkylene glycol ester (PAG ester), polyvinyl ether (PVE), poly(alpha-olefin), and combinations thereof, and preferably selected from PAG or POE.

29. A composition comprising a stabilizer and a composition according to any one of the prior claims, wherein the stabilizer is preferably selected from diene compounds, phosphates, phenol compounds (such as 2,6-di-tert-butyl-4-methylphenol), epoxides, and mixtures thereof.

30. A composition comprising a flame retardant and a composition according to any one of the prior claims, wherein the flame retardant is selected from the group consisting of tri-(2-chloroethyl)-phosphate, (chloropropyl)-phosphate, tri-(2,3-dibromopropyl)-phosphate, tri-(1,3-dichloropropyl)-phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, polyvinyl chloride, fluorinated iodocarbon, fluorinated bromocarbon, trifluoroiodomethane, perfluoroalkylamine, bromo-fluoroalkylamine, and mixtures thereof.

31. A liquid chiller system comprising a composition according to any one of the prior claims, wherein the liquid chiller system comprises at least one counterflow heat exchanger for exchanging heat between the composition and the liquid.

32. The liquid chiller system according to claim 31, wherein the system is adapted for cooling and / or heating a passenger compartment and / or for cooling the battery of an electric vehicle.

33. The liquid chiller system according to claim 31 or 32, wherein the liquid is selected from water, brine, glycol, synthetic hydrocarbon fluid, silicone fluid, or fully or partially fluorinated organic fluid (e.g., fluorinated ether or ketone), a fluid blend of freezing point lowering additives or viscosity lowering additives (such as triacetin, diacetin, acetone, and / or carbon dioxide), and mixtures thereof.

34. A thermal management system for an electric vehicle, comprising a liquid chiller system according to any one of claims 31 to 33.

35. Use of the composition according to any one of claims 1 to 30 as a refrigerant in a heat transfer device comprising at least one counterflow heat exchanger for exchanging heat between the composition and a liquid, wherein the heat transfer device is a liquid chiller system and / or is incorporated into a thermal management system of an electric vehicle.

36. Use of the composition according to any one of claims 1 to 30 as a substitute for an existing refrigerant.

37. The use according to claim 36, wherein the existing refrigerant is propane and / or 2,3,3,3-tetrafluoropropene (R-1234yf), or comprises the same, for example, the existing refrigerant is propane or R-1234yf.

38. The use according to claim 36 or 37, wherein the use is as a substitute for the existing refrigerant in a liquid chiller system.

39. The use according to claim 38, wherein the liquid chiller system is adapted for cooling and / or heating a passenger compartment and / or for cooling the battery of an electric vehicle.

40. A method for generating cooling, comprising evaporating a composition according to any one of claims 1 to 30 near an object to be cooled.

41. A method for generating heating, comprising condensing a composition according to any one of claims 1 to 30 near an object to be heated.

42. A method for modifying a heat transfer device, comprising the steps of removing an existing heat transfer composition and introducing a composition according to any one of claims 1 to 30, wherein the heat transfer device is, for example, a thermal management system for an electric vehicle.

43. The method according to claim 42, wherein the existing heat transfer composition is propane (R-290) or 2,3,3,3-tetrafluoropropene (R-1234yf).

44. The method according to claim 42 or 43, wherein the existing refrigerant is propane and / or 2,3,3,3-tetrafluoropropene (R-1234yf), or comprises the same, for example, the existing refrigerant is propane or R-1234yf.

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