Heat transfer composition

Abstract

The present invention provides a composition comprising 1,1-difluoroethylene (R-1132a), difluoromethane (R-32), 2,3,3,3-tetrafluoropropylene (R-1234yf), carbon dioxide (CO2, R-744), and optionally 1,1,2-trifluoroethylene (R-1123). The present invention also provides a composition comprising the composition, a heat transfer device, a sprayable composition, and uses of the composition.

Description

[0001] This application is a divisional application of the Chinese patent application with an application date of August 6, 2018, application number "201880051258.0", and invention name "Composition". The original application is the Chinese national phase application of international application PCT / GB2018 / 052243. Technical Field

[0002] The present invention relates to compositions, preferably heat transfer compositions, which may be suitable for replacing existing refrigerants such as R-410A. Background Art

[0003] The listing or discussion of a prior-published document or any background in this specification should not necessarily be taken as an admission that the document or background is part of the state of the art or is common general knowledge.

[0004] Mechanical refrigeration systems and related heat transfer devices, such as heat pumps and air conditioning systems, are well known. In such systems, a refrigerant liquid evaporates at low pressure, removing heat from the surrounding area. The resulting vapor is then compressed and transferred to a condenser, where it condenses and releases heat to a second area. The condensate is then returned to the evaporator through an expansion valve, completing the cycle. The mechanical energy required to compress the vapor and pump the liquid is provided by, for example, an electric motor or internal combustion engine.

[0005] Residential and light commercial air conditioners and heat pump units are typically equipped with the non-flammable refrigerant R-410A, a blend of R-32 (difluoromethane) and R-125 (pentafluoroethane). Although using this refrigerant can result in high system efficiency and thus lower energy consumption, R-410A has a high greenhouse (or global) warming potential (GWP) (2100 using the IPCC AR4 dataset).

[0006] R-32 (difluoromethane) has been proposed as a replacement for R-410A. R-32 is classified as mildly flammable ("2L" using the ASHRAE classification system). In properly designed equipment, it offers energy efficiency comparable to R-410A and has a GWP of 675. However, R-32 has a number of disadvantages: its compressor discharge temperature is significantly higher than that of R-410A, and its operating pressure may also be higher than that of R-410A. These higher discharge temperatures can be compensated for, for example, by using "demand cooling" or liquid injection techniques. However, these may reduce the capacity and energy efficiency of the system. Another disadvantage of R-32 is that its GWP (675) is still high compared to the GWP of hydrofluoroolefin refrigerants (such as tetrafluoropropylenes) or hydrocarbons (such as propane).

[0007] Binary blends of R-32 with R-1234yf (2,3,3,3-tetrafluoropropene) or R-1234ze(E) (E-1,3,3,3-tetrafluoropropene), as well as ternary blends of R-32, a tetrafluoropropene (R-1234ze(E) or R-1234yf) and a third component, have also been proposed as alternative fluids. Examples of such fluids include R-454B, a binary mixture of R-32 / R-1234yf (68.9% / 31.1%) with a GWP of 466, and R-452B, a ternary mixture of R-32 / R-125 / R-1234yf (67% / 7% / 26%) with a GWP of 698. These fluids have reduced GWPs compared to R-410A and can provide reduced discharge temperatures. However, their GWP values are similar to those of R-32 and are still high compared to the GWP of hydrofluoroolefin refrigerants or hydrocarbons.

[0008] When searching for an alternative low-temperature refrigerant, several other factors must be considered. First, if the fluid is to be used as a retrofit or conversion fluid in existing equipment, or as a "drop-in component" for new equipment using a largely unchanged R-410A system design, then non-flammability is highly desirable because the existing design will already be based on the use of a non-flammable fluid.

[0009] If an alternative fluid is to be used in a completely new system design, a certain degree of flammability may be tolerated, but using a highly flammable fluid may impose a cost and performance penalty to reduce the risk of potential damage. The acceptable charge (refrigerant mass) in the system is also limited by the flammability classification of the fluid, with the most stringent restrictions being Class 3 fluids such as ethane. In this case, less flammable characteristics are highly desirable as this may allow for a larger system charge.

[0010] Third, typical applications for such fluids are in residential or commercial air conditioning and heat pump units, which are typically located in buildings. Therefore, it is advantageous to have acceptably low toxicity as a characteristic of the fluid.

[0011] Furthermore, both volumetric capacity (a measure of the cooling power achievable by a compressor of a given size) and energy efficiency are important.

[0012] Therefore, there is a need to provide alternative refrigerants that have improved properties such as low GWP (to reduce the environmental impact of refrigerant leaks) while also having acceptable refrigeration performance, flammability characteristics, and toxicology. There is also a need to provide alternative refrigerants that can be used in existing equipment (such as refrigeration equipment) with little or no modification.

[0013] More specifically, it would be advantageous to find a refrigerant blend that has comparable performance (capacity and energy efficiency, expressed as COP) to R-410A and comparable compressor discharge temperatures to those of R-452B or R-454A, but with a GWP significantly lower than that of R-32. Since both R-32 and R-454B are considered weakly flammable blends (flammability classification "2L" according to ASHRAE Standard 34), such a lower GWP blend would also be desirable to have a flammability classification of 2L. Summary of the Invention

[0014] The present invention addresses the above and other deficiencies and needs by providing a composition comprising 1,1-difluoroethylene (R-1132a), difluoromethane (R-32), 2,3,3,3-tetrafluoropropylene (R-1234yf), optionally carbon dioxide (CO2, R-744), and optionally 1,1,2-trifluoroethylene (R-1123). Such a composition is hereinafter referred to as the composition of the present invention.

[0015] The compositions of the present invention typically contain from about 1 or 2 or 3 or 4 to about 60% by weight of R-1132a. Advantageously, such compositions contain from about 1 or 2 or 3 or 4 to about 50% by weight of R-1132a, such as from about 1 or 2 or 3 or 4 to about 40% by weight of R-1132a, for example from about 1 or 2 or 3 or 4 to about 30% by weight of R-1132a. Conveniently, the compositions of the present invention contain from about 1 or 2 or 3 or 4 to about 25% by weight of R-1132a, such as from 2 to about 20% by weight of R-1132a, for example from 3 or 4 to about 20% by weight of R-1132a. Preferably, such compositions contain from about 5 to about 20% by weight of R-1132a.

[0016] The compositions of the present invention typically contain from about 1 to about 99% by weight R-32 or from about 2 to about 98% by weight R-32. Advantageously, such compositions contain from about 2 to about 95% by weight R-32, such as from about 3 to about 95% by weight R-32. Conveniently, the compositions of the present invention contain from about 5 to about 90% by weight R-32, such as from about 5 to about 85% by weight R-32, for example from about 10 to about 80% by weight R-32. Preferably, such compositions contain from about 15 to about 75% by weight R-32, such as from about 15 to about 70% by weight R-32.

[0017] The compositions of the present invention typically contain from about 1 to about 99% by weight of R-1234yf or from about 2 to about 98% by weight of R-1234yf. Advantageously, such compositions contain from about 2 to about 90% by weight of R-1234yf, such as from 5 to about 90% by weight of R-1234yf. Conveniently, the compositions of the present invention contain from about 7 to about 85% by weight of R-1234yf, such as from about 8 to about 80% by weight of R-1234yf. Preferably, such compositions contain from about 10 to about 75% by weight of R-1234yf, such as from about 10 to about 70% by weight of R-1234yf, for example from about 10 to about 65% by weight of R-1234yf.

[0018] Conveniently, the compositions of the present invention comprise from about 1 to about 60% by weight of R-1132a, from about 1 to about 99% by weight of R-32, and from about 1 to about 99% by weight of R-1234yf. Such compositions typically comprise from about 1 to about 50% by weight of R-1132a, from about 2 to about 97% by weight of R-32, and from about 2 to about 97% by weight of R-1234yf.

[0019] Conveniently, the compositions of the present invention comprise from about 2 to about 60% by weight of R-1132a, from about 1 to about 97% by weight of R-32, and from about 1 to about 97% by weight of R-1234yf. Such compositions typically comprise from about 2 to about 50% by weight of R-1132a, from about 2 to about 96% by weight of R-32, and from about 2 to about 96% by weight of R-1234yf.

[0020] Advantageously, the compositions of the present invention comprise from about 1 to about 40% by weight R-1132a, from about 5 to about 90% by weight R-32, and from about 5 to about 90% by weight R-1234yf; or from about 2 to about 40% by weight R-1132a, from about 5 to about 90% by weight R-32, and from about 5 to about 90% by weight R-1234yf; or from about 2 to about 40% by weight R-1132a, from about 4 to about 94% by weight R-32, and from about 4 to about 94% by weight R-1234yf.

[0021] Preferably, the compositions of the present invention comprise from about 3 to about 20% by weight R-1132a, from about 10 to about 80% by weight R-32, and from about 10 to about 75% by weight R-1234yf; or from about 3 to about 30% by weight R-1132a, from about 10 to about 91% by weight R-32, and from about 6 to about 87% by weight R-1234yf.

[0022] Conveniently, the compositions of the present invention comprise from about 5 to about 20% by weight R-1132a, from about 20 to about 70% by weight R-32, and from about 10 to about 65% by weight R-1234yf; or from about 4 to about 25% by weight R-1132a, from about 15 to about 88% by weight R-32, and from about 8 to about 81% by weight R-1234yf.

[0023] Any of the above compositions may additionally contain carbon dioxide (R-744, CO2). Adding R-744 has the advantage of reducing R-1132a in the vapour phase and thus reducing the flammability potential of the vapour phase, but tends to increase the compressor discharge temperature and temperature glide.

[0024] When present, the compositions of the present invention typically contain from about 1 to about 20% by weight of CO2. Preferably, such compositions contain from about 2 to about 15% by weight of CO2. In one embodiment, the compositions of the present invention contain a combined amount of R-1132a and CO2 of from about 2 to about 50% by weight, such as from about 2 to about 40% by weight, for example from about 4 to about 30% by weight, for example from about 5 to about 20% by weight.

[0025] Any of the above compositions may additionally contain 1,1,2-trifluoroethylene (R-1123). An advantage of using R-1123 in the compositions of the present invention is that it gives a capacity similar to R-32, but with a negligible GWP. By incorporating a certain proportion of R-1123, the overall GWP of a composition having a capacity similar to R-410A can be reduced compared to an equivalent ternary R-1132a / R-32 / R-1234yf composition with unchanged R-1132a and R-1234yf ratios. R-1123 can only be safely used as a diluted component in the compositions of the present invention. Generally, the proportion of R-1123 in the composition is such that the maximum molar concentration of R-1123 in the formulated composition of the present invention or in its worst-case graded composition (as defined in ASHRAE Standard 34, Annex B) should be less than 40%.

[0026] When present, the compositions of the present invention typically contain from about 1 to about 30% by weight of R- 1123; or from about 5 to about 30% by weight of R- 1123. Preferably, such compositions contain from about 5 to about 20% by weight of R- 1123, such as from about 5 to about 15% by weight, for example from about 5 to about 10% by weight of R- 1123.

[0027] Alternatively, the compositions of the present invention may contain less than about 8% or about 7% or about 6% or about 5% by weight of R-1123, such as less than about 4% or about 3% by weight of R-1132a, for example less than about 2% or about 1% by weight of R-1123. Preferably, such compositions are substantially free of R-1123. Advantageously, the compositions of the present invention are free of (readily detectable) R-1123.

[0028] Any of the above compositions can also contain hydrocarbons. Advantageously, hydrocarbons are one or more compounds selected from the group consisting of ethane, propane, propylene, isobutane, normal butane, n-pentane, isopentane and mixtures thereof. Without being bound by theory, it is believed that, when present, comprising ethane and / or other hydrocarbon compounds can enhance oil miscibility, solubility and / or reflux characteristics. Typically, compositions of the present invention contain approximately 1 to approximately 20% hydrocarbon components by weight, such as approximately 1 to approximately 10% by weight, for example approximately 1 to approximately 5% by weight. DETAILED DESCRIPTION

[0029] In embodiments, the composition may consist essentially of the components. By the term "consisting essentially of," it is included that the composition of the present invention is substantially free of other components, particularly free of other (hydrogen)(fluoro) compounds known for use in heat transfer compositions (e.g., (hydrogen)(fluoro)alkanes or (hydrogen)(fluoro)olefins). The term "consisting of" is included within the meaning of "consisting essentially of."

[0030] In one embodiment, the compositions of the present invention are substantially free of any components having heat transfer properties (except for the components specified).For example, the compositions of the present invention can be substantially free of any other hydrofluorocarbons.

[0031] By "substantially free" and "substantially free" is included the meaning that the composition of the present invention contains 0.5% or less by weight of the component, preferably 0.4%, 0.3%, 0.2% or 0.1% or less, based on the total weight of the composition.

[0032] All chemicals described herein are commercially available. For example, fluorine-containing compounds can be obtained from Apollo Scientific (UK), and carbon dioxide can be obtained from liquefied gas suppliers such as Linde AG.

[0033] As used herein, unless otherwise indicated, all % amounts referred to in compositions herein (including the claims) are by weight based on the total weight of the composition.

[0034] The term "about" as used in conjunction with a numerical value of a component amount in % by weight includes a meaning of ±0.5% by weight, for example ±0.5% by weight.

[0035] For the avoidance of doubt, it should be understood that the stated upper and lower limits of the ranges for amounts of components in the compositions of the present invention described herein may be interchanged in any manner provided that the resulting ranges fall within the broadest scope of the invention.

[0036] The compositions of the present invention have zero ozone depletion potential.

[0037] Typically, the compositions of the present invention have a GWP of less than about 650, such as less than about 600, for example less than about 500. Preferably, the compositions of the present invention have a GWP of less than about 480, such as less than about 450, for example less than about 400.

[0038] Generally, the compositions of the present invention have a reduced flammability hazard compared to R-1132a.

[0039] Flammability may be determined according to ASHRAE Standard 34 in conjunction with ASTM Standard E-681 and the test methods per 2004 Appendix 34p, the entire contents of which are incorporated herein by reference.

[0040] In one aspect, the composition has one or more of the following compared to R-1132a alone: (a) a higher lower flammable limit; (b) a higher ignition energy (sometimes referred to as auto-ignition energy or pyrolysis); or (c) a lower flame speed. Preferably, the composition of the invention is less flammable than R-1132a in one or more of the following aspects: a lower flammable limit at 23°C; a lower flammable limit at 60°C; a width of the flammable range at 23°C or 60°C; an auto-ignition temperature (thermal decomposition temperature); a minimum ignition energy or flame speed in dry air. The flammable limits are determined according to the method specified in ASHRAE-34, and the auto-ignition temperature is determined by the method of ASTM E659-78 in a 500 ml glass flask.

[0041] In a preferred embodiment, the compositions of the present invention are non-flammable. For example, using the ASHRAE-34 method, the compositions of the present invention are non-flammable at a test temperature of 60°C. Advantageously, vapor mixtures in equilibrium with the compositions of the present invention at any temperature between about -20°C and 60°C are also non-flammable.

[0042] In some applications, it may not be necessary to classify a formulation as non-flammable by ASHRAE-34. It may be possible to develop a fluid whose flammability limit in air will be sufficiently reduced to make it safe for use in an application, for example if it is physically impossible to discharge a flammable mixture into the surrounding environment through leaking refrigeration equipment.

[0043] In one embodiment, the composition of the present invention has a flammability classification of 1 or 2L according to the ASHRAE Standard 34 classification method, which indicates non-flammable (Class 1) or weakly flammable fluid with a flame speed less than 10 cm / s (Class 2L).

[0044] The compositions of the present invention preferably have a temperature glide in the evaporator or condenser of less than about 10 K, even more preferably less than about 5 K, and even more preferably less than about 1 K.

[0045] It is believed that the compositions of the present invention exhibit a completely unexpected combination of low / non-flammability, low GWP, improved lubricant miscibility and improved refrigeration performance properties. Some of these refrigeration performance properties are described in more detail below.

[0046] The compositions of the present invention typically have a volumetric refrigeration capacity of at least 80% of the volumetric refrigeration capacity of R-410A, such as at least 85% of the volumetric refrigeration capacity of R-410A. Preferably, the compositions of the present invention have a volumetric refrigeration capacity of at least 90% of the volumetric refrigeration capacity of R-410A, for example from about 95% to about 130% of the volumetric refrigeration capacity of R-410A.

[0047] In one embodiment, the cycle efficiency (coefficient of performance, COP) of the composition of the present invention is within about 7% of R-410A, such as within 5% of R-410A. Preferably, the cycle efficiency is equal to or higher than R-410A.

[0048] Conveniently, the compressor discharge temperature of the compositions of the present invention is within about 15 K of the existing refrigerant fluid (e.g., R-410A or R-32) that it replaces, preferably about 10 K or even about 5 K. Advantageously, the compressor discharge temperature of the compositions of the present invention is lower than the compressor discharge temperature of R-32.

[0049] Conveniently, the operating pressure in the condenser containing the composition of the present invention is lower than the operating pressure of the condenser containing R-32.

[0050] The compositions of the present invention are generally suitable for use with existing equipment designs and are compatible with all types of lubricants used with current and established HFC refrigerants. The compositions may optionally be stabilized or made compatible with mineral oils through the use of suitable additives.

[0051] Preferably, when used in heat transfer equipment, the compositions of the present invention are combined with a lubricant.

[0052] Conveniently, the lubricant is selected from the group consisting of mineral oil, silicone oil, polyalkylbenzene (PAB), polyol ester (POE), polyalkylene glycol (PAG), polyalkylene glycol ester (PAG ester), polyvinyl ether (PVE), poly(α-olefin), and combinations thereof. PAG and POE are currently preferred lubricants for the compositions of the present invention.

[0053] Advantageously, the lubricant also includes a stabilizer.

[0054] Preferably, the stabilizer is selected from the group consisting of diene-based compounds, phosphates, phenolic compounds and epoxides, and mixtures thereof.

[0055] Conveniently, the composition of the present invention may be combined with a flame retardant.

[0056] Advantageously, the flame retardant is selected from the group consisting of tris(2-chloroethyl)-phosphate, (chloropropyl)-phosphate, tris(2,3-dibromopropyl)-phosphate, tris(1,3-dichloropropyl)-phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, polyvinyl chloride, iodocarbon fluoride, bromocarbon fluoride, trifluoroiodomethane, perfluoroalkylamines, bromo-fluoroalkylamines and mixtures thereof.

[0057] In one embodiment, the present invention provides a heat transfer device comprising a composition of the present invention. Preferably, the heat transfer device is a refrigeration device.

[0058] Conveniently, the heat transfer device is a residential or commercial air conditioning system, a heat pump, or a commercial or industrial refrigeration system.

[0059] The present invention also provides for use of a composition of the present invention in a heat transfer device as described herein, such as a refrigeration system.

[0060] According to another aspect of the present invention, there is provided a sprayable composition comprising a material to be sprayed and a propellant comprising a composition of the present invention.

[0061] According to a further aspect of the present invention there is provided a method of cooling an article, the method comprising condensing a composition of the present invention and thereafter evaporating the composition in the vicinity of the article to be cooled.

[0062] According to another aspect of the present invention there is provided a method of heating an article, the method comprising condensing a composition of the present invention in the vicinity of the article to be heated and thereafter evaporating the composition.

[0063] According to yet another aspect of the present invention, there is provided a method of extracting a substance from biomass, the method comprising contacting the biomass with a solvent comprising the composition of the present invention, and separating the substance from the solvent.

[0064] According to another aspect of the present invention, there is provided a method of cleaning an article, the method comprising contacting the article with a solvent comprising a composition of the present invention.

[0065] According to yet another aspect of the present invention, there is provided a method of extracting a material from an aqueous solution, the method comprising contacting the aqueous solution with a solvent comprising the composition of the present invention, and separating the material from the solvent.

[0066] According to another aspect of the present invention there is provided a method of extracting a material from a particulate solid matrix, the method comprising contacting the particulate solid matrix with a solvent comprising a composition of the present invention, and separating the material from the solvent.

[0067] According to yet another aspect of the present invention, there is provided a mechanical power generation device comprising the composition of the present invention.

[0068] Preferably, the mechanical power generation device is adapted to use a Rankine cycle or a variation thereof to generate work from heat.

[0069] According to another aspect of the present invention, a method for modifying a heat transfer device is provided, comprising the steps of removing an existing heat transfer fluid and introducing a composition of the present invention. Preferably, the heat transfer device is a refrigeration device, such as a cryogenic refrigeration system. Advantageously, the method further comprises the step of obtaining greenhouse gas (e.g., carbon dioxide) emission credits.

[0070] According to the above modification method, the existing heat transfer fluid can be completely removed from the heat transfer device before introducing the composition of the present invention. The existing heat transfer fluid can also be partially removed from the heat transfer device and then the composition of the present invention is introduced.

[0071] The compositions of the present invention can also be prepared simply by mixing R-1132a, R-32, R-1234yf (and optional components such as R-744, R-1123, hydrocarbons, lubricants, stabilizers or additional flame retardants) in the desired proportions. The composition can then be added to a heat transfer device (or used in any other manner as defined herein).

[0072] In yet another aspect of the present invention, there is provided a method of reducing the environmental impact caused by the operation of a product comprising an existing compound or composition, the method comprising at least partially replacing the existing compound or composition with a composition of the present invention.

[0073] Environmental impacts include the generation and emission of greenhouse gases during the operation of the product.

[0074] As mentioned above, this environmental impact can be considered to include not only the emissions of those compounds or compositions that have a significant environmental impact due to leakage or other losses, but also the carbon dioxide emissions generated by the energy consumed by the device during its operating life. This environmental impact can be quantified by a measure called the Total Equivalent Warming Impact (TEWI). This measure has been used to quantify the environmental impact of certain stationary refrigeration and air conditioning equipment (including, for example, supermarket refrigeration systems).

[0075] The environmental impact can also be considered to include greenhouse gas emissions resulting from the synthesis and manufacture of a compound or composition. In this case, manufacturing emissions are added to energy consumption and direct cost impacts to arrive at a measure known as life cycle carbon production (LCCP). LCCP is commonly used to assess the environmental impact of automotive air conditioning systems.

[0076] In preferred embodiments, devices produced using the compositions of the present invention have lower total equivalent warming impact and / or lower life cycle carbon production than would be achieved by using existing compounds or compositions.

[0077] These methods can be performed on any suitable product in the field of air conditioning, refrigeration (e.g., cryogenic and ultra-cold refrigeration), heat transfer, aerosol or sprayable propellants, gaseous dielectrics, flame suppression, solvents (e.g., carriers for flavors and fragrances), cleaning agents, local anesthetics, and expansion applications, preferably, the field is refrigeration.

[0078] Examples of suitable products include heat transfer devices, sprayable compositions, solvents, and mechanical power generation devices.In a preferred embodiment, the product is a heat transfer device, such as a refrigeration device.

[0079] The existing compound or composition has a greater environmental impact as measured by GWP and / or TEWI and / or LCCP than the composition of the present invention that replaces it. The existing compound or composition may include a fluorocarbon, such as a perfluorocarbon, hydrofluorocarbon, chlorofluorocarbon or hydrochlorofluorocarbon, or it may include a fluorinated olefin.

[0080] Preferably, the existing compound or composition is a heat transfer compound or composition, such as a refrigerant. Examples of refrigerants that may be replaced include R-410A, R454B, R-452B and R-32, preferably R-410A.

[0081] Any amount of an existing compound or composition can be replaced to reduce environmental impact. This may depend on the environmental impact of the existing compound or composition being replaced and the environmental impact of the alternative composition of the present invention. Preferably, the existing compound or composition in the product is completely replaced by the composition of the present invention.

[0082] The invention is illustrated by the following non-limiting examples.

[0083] Example

[0084] Ternary mixture of R-1132a, R-32 and R-1234yf

[0085] A thermodynamic model was constructed to allow estimation of the performance of compositions containing R-1132a or CO2 in vapor compression refrigeration or air conditioning cycles. The critical temperature of R-1132a is approximately 30°C, and the critical temperature of CO2 is approximately 31°C; both are lower than the condensing temperature encountered in many applications of R-410A, which can range from 30 to 60°C. Therefore, a thermodynamic model was developed that is capable of predicting the vapor-liquid equilibrium of a mixture at temperatures above the critical temperatures of some of the components in the mixture.

[0086] The selected model uses the Peng-Robinson equation of state to calculate the thermodynamic properties of the mixture. The vapor-liquid equilibrium (VLE) of the mixture is related using the Peng-Robinson equation of state in combination with the mixing rules of Wong and Sandler, as described in Orbey, H., & Sandler, S. (1998), Modeling Vapor-Liquid Equilibria: Cubic Equations of State and their Mixing Rules, Cambridge: Cambridge University Press, which is incorporated herein by reference. This type of thermodynamic model has been successfully used to model the VLE of refrigerant mixtures (Shiflett, M., & Sandler, S. (1998), Modeling Fluorocarbon Vapor-Liquid Equilibria using the Wong-Sandler Model, Fluid Phase Equilibria, 145-162, incorporated herein by reference), and to model the VLE of mixtures in which one of the substances is above its critical temperature (Valtz, A., Coquelet, C., & Richon, D. (2007), Vapor–liquid equilibrium data for the hexafluoroethane + carbon dioxide system at temperatures from 253 to 297 K and pressures up to 6.5 MPa, Fluid Phase Equilibria, 179-185, incorporated herein by reference). The Wong-Sandler model also allows for reliable prediction of the VLE of a mixture at temperatures and pressures higher than those used to generate the experimental data used to regress its mixture parameters, by combining a free energy model for the liquid phase with the equations of state parameters. This makes it suitable for estimating the vapor compression cycle performance of the mixture under consideration.

[0087] In this work, the Wong-Sandler mixing rule was used with the non-stochastic two-liquid (NRTL) model to represent the free energy of the liquid phase. The Peng-Robinson equation parameters for each mixture component were modified to use the temperature dependence of Mathias and Copeman in order to accurately represent the component vapor pressures.

[0088] The interaction parameters of the Wong-Sandler / NRTL model were applied to R-1132a and CO 2、 Experimental measurements of the vapour-liquid equilibrium of binary mixtures of R-32 and R-1234yf were regressed. The temperature range of the experimental measurements used was -55 to +10°C for R-1132a / CO2 and R-1132a / R-32 mixtures, and -40 to +40°C for R-1132a / R-1234yf mixtures. Data for these mixtures, as well as for binary mixtures of R1234yf with R-32 and CO2, were measured using a static synthetic equilibrium cell.

[0089] Literature data on the VLE of R-32 with CO2 (Rivollet, F., Chapoy, C., Coquelet, C., & Richon, D. (2004), Vapor-liquid equilibrium data for the carbon dioxide (CO2) + difluoromethane (R32) system at temperatures from 283.12 to 343.25 K and pressures up to 7.46 MPa, Fluid Phase Equilibria, 95-101, incorporated herein by reference) (Adams RA, Stein FP. (1971), Vapor-Liquid Equilibria for Carbon Dioxide-Difluoromethane System, Journal of Chemical Engineering Data, 1146-149., incorporated herein by reference), and literature data on the VLE of R-1234yf with CO2 (Juntarachat, N. et al. (2014), Experimental measurements and correlation of vapor-liquid equilibrium and Critical data for the CO2+R1234yf and CO2+R1234ze(E) binary mixtures, International Journal of Refrigeration, 141-152, incorporated herein by reference) were also available and used for parameter regression.

[0090] Cycle modeling was performed using the state points in the modeling matrix proposed by AHRI's Low-GWP Alternative Refrigerants Evaluation Programme. The conditions used are given in Table 1 below:

[0091] Table 1: Cycle conditions for modeling the R-1132a / R-32 / R-124yf ternary system

[0092]

[0093] To verify that the thermodynamic model gave reasonable results, the cycling performance of R-410A was simulated using the industry standard NIST REFPROP9.1 program for comparison. The cycling performance was then calculated using the Mexichem thermodynamic model. The results are shown in Table 2 below.

[0094] Table 2: Comparison of REFPROP and Mexichem thermodynamic model results

[0095]

[0096]

[0097] First, the performance of R-32 and R-454B was compared using this model. The results are shown in Table 3 below.

[0098] Table 3: Modeled data on the refrigeration performance of R-32 and R-454B relative to R-410A

[0099]

[0100] Next, a series of compositions of R-1132a / R-32 / R-1234yf ranging from 5-20% R-1132a and 20-70% R-32 were analyzed. The results are shown in Tables 4-7 below. The composition of each component is given in weight percent in these tables.

[0101] Table 4: Refrigeration performance modeling data for the R-1132a / R-32 / R-1234yf ternary system containing 5% R-1132a

[0102]

[0103] Table 5: Refrigeration performance modeling data for the R-1132a / R-32 / R-1234yf ternary system containing 10% R-1132a

[0104]

[0105] Table 6: Refrigeration performance modeling data for the R-1132a / R-32 / R-1234yf ternary system containing 15% R-1132a

[0106]

[0107] Table 7: Refrigeration performance modeling data for the R-1132a / R-32 / R-1234yf ternary system containing 20% R-1132a

[0108]

[0109] Unexpectedly, the results show that it is possible to formulate ternary blends of R-1132a / R-32 / R-1234yf with acceptable performance compared to R-410A, while achieving a GWP lower than that of R-32 or R-454B.

[0110] Particularly preferred compositions are those that can be classified as having a "2L" flammability and which can be used on a "built-in" or "near built-in" basis in systems designed for R-410A. Such compositions are considered to meet the following criteria:

[0111] · Capacity of at least about 90% of R-410A

[0112] COP is equal to or higher than that of R-410A

[0113] The operating pressure in the condenser is equal to or lower than the operating pressure of R-32

[0114] The compressor discharge temperature is lower than the discharge temperature of R-32

[0115] The temperature "glide" in the evaporator and condenser is less than about 10K

[0116] According to ASHRAE Standard 34, the worst case burning velocity of the composition is less than 10 cm / s

[0117] Other compositions that offer acceptable operating pressures and flammability, but do not meet all of these criteria, may also provide acceptable performance in appropriately designed new equipment. For example, blends with volumetric capacities less than 90% of the volumetric capacity of R-410A may be used by increasing the compressor displacement or compressor speed. Blends with temperature glides greater than 10 K may be used by employing cross-countercurrent heat exchanger designs for the condenser and / or evaporator.

[0118] Blends that have good performance properties but exhibit Class 2 flammability may also be used in systems where the charge level and application conditions make their use safe.

Claims

1. A composition comprising: (i) 2 to 30% by weight of 1,1-difluoroethylene (vinylidene fluoride, R-1132a); (ii) 10 to 80% by weight of difluoromethane (R-32); (iii) 7 to 85% by weight of 2,3,3,3-tetrafluoropropene (R-1234yf); and (iv) 1 to 20% by weight of carbon dioxide (CO2).

2. A composition according to claim 1 comprising 3 to 20% by weight of R-1132a.

3. A composition according to claim 2 comprising 5 to 20% by weight of R-1132a.

4. A composition according to claim 1 comprising 10 to 75% by weight of R-1234yf.

5. A composition according to claim 4 comprising from 10 to 65% by weight of R-1234yf.

6. The composition of claim 1, wherein CO2 is present in an amount of 2 to 20% by weight.

7. A composition according to claim 6, wherein CO2 is present in an amount of 2 to 15% by weight.

8. The composition according to claim 1, wherein The combined amount of R-1132a and CO2 present is 4 to 30% by weight.

9. The composition according to claim 8, wherein The combined amount of R-1132a and CO2 present is 5 to 20% by weight.

10. The composition of claim 1, further comprising 1,1,2-trifluoroethylene (R-1123).

11. A composition according to claim 10 wherein R-1123 is present in an amount of 1 to 30% by weight.

12. A composition according to claim 11 wherein R-1123 is present in an amount of 5 to 20% by weight.

13. The composition according to claim 1, wherein The composition contains less than 0.5% by weight of 1,1,2-trifluoroethylene (R-1123).

14. The composition according to claim 13, wherein The composition does not contain 1,1,2-trifluoroethylene (R-1123).

15. The composition of claim 1, consisting essentially of said components.

16. The composition according to claim 1, wherein The composition is less flammable than R-1132a alone.

17. The composition according to claim 16, wherein Compared to R-1132a alone, the composition has: a. Higher flammability limits; b. Higher ignition energy; and / or c. Lower flame speed.

18. The composition according to claim 1, wherein The composition is non-flammable.

19. The composition according to claim 18, wherein The composition is non-flammable at ambient temperature.

20. The composition of claim 19, wherein the composition is non-flammable at 60°C.

21. The composition according to claim 1, wherein The composition has a volumetric refrigeration capacity that is at least 90% of the volumetric refrigeration capacity of R-410A.

22. The composition according to claim 1, wherein The composition has a coefficient of performance (COP) equal to or higher than that of R-410A.

23. The composition according to claim 1, wherein The composition has an operating pressure in the condenser that is equal to or lower than that of R-32.

24. The composition according to claim 1, wherein The composition has a compressor discharge temperature that is lower than the discharge temperature of R-32.

25. The composition according to claim 1, wherein The composition has a temperature glide of less than 10 K in the evaporator or condenser.

26. The composition according to claim 25, wherein The composition has a temperature glide of less than 5 K in the evaporator or condenser.

27. The composition according to claim 1, wherein The composition has a burning velocity as measured by ASHRAE Standard 34 of less than 10 cm / s.

28. A composition comprising a lubricant and the composition of claim 1.

29. The composition according to claim 28, wherein The lubricant is selected from the group consisting of mineral oil, silicone oil, polyalkylbenzene (PAB), polyol ester (POE), polyalkylene glycol (PAG), polyalkylene glycol ester (PAG ester), polyvinyl ether (PVE), poly(α-olefin), and combinations thereof.

30. The composition of claim 29, wherein the lubricant is selected from PAG or POE.

31. A composition comprising a stabilizer and the composition of claim 1.

32. The composition according to claim 31, wherein The stabilizer is selected from the group consisting of diene-based compounds, phosphates, phenolic compounds and epoxides, and mixtures thereof.

33. A composition comprising a flame retardant and the composition of claim 1.

34. The composition according to claim 33, wherein The flame retardant is selected from the group consisting of tris(2-chloroethyl)-phosphate, (chloropropyl)-phosphate, tris(2,3-dibromopropyl)-phosphate, tris(1,3-dichloropropyl)-phosphate, diammonium phosphate, various halogenated aromatic compounds, antimony oxide, aluminum trihydrate, polyvinyl chloride, iodine carbon fluoride, bromocarbon fluoride, trifluoroiodomethane, perfluoroalkylamine, bromo-fluoroalkylamine and mixtures thereof.

35. A thermal transfer device comprising a composition as defined in any one of claims 1 to 34.

36. The heat transfer device of claim 35, wherein The heat transfer device is a refrigeration device.

37. The heat transfer device of claim 35, wherein: The heat transfer device includes a residential or commercial air conditioning system, a heat pump, or a commercial or industrial refrigeration system.

38. Use of a composition as defined in any one of claims 1 to 34 in a heat transfer device.

39. The use according to claim 38, wherein the heat transfer device is a refrigeration device.

40. A sprayable composition comprising a material to be sprayed and a propellant comprising a composition as defined in any one of claims 1 to 34.

41. A method for cooling an article comprising condensing a composition as defined in any one of claims 1 to 34 and thereafter evaporating said composition in the vicinity of said article to be cooled.

42. A method for heating an article, comprising condensing a composition as defined in any one of claims 1 to 34 in the vicinity of the article to be heated, and thereafter evaporating the composition.

43. A mechanical power generation device comprising a composition as defined in any one of claims 1 to 34.

44. A mechanical power generating device according to claim 43 adapted to generate work from heat using a Rankine cycle or a variation thereof.

45. A method of retrofitting a heat transfer device comprising the steps of removing an existing heat transfer composition and introducing a composition as defined in any one of claims 1 to 34.

46. The method of claim 45, wherein The heat transfer device is a commercial or industrial refrigeration unit, a heat pump, or a residential or commercial air conditioning system.

47. A method for reducing the environmental impact caused by the operation of a product comprising an existing compound or composition, the method comprising at least partially replacing the existing compound or composition with a composition as defined in any one of claims 1 to 34.

48. The method of claim 47, wherein The method results in a lower total equivalent warming impact and / or lower life cycle carbon production than that obtained by using the existing compound or composition.

49. The method of claim 47, performed on products from the fields of air conditioning, refrigeration, heat transfer, aerosol or sprayable propellants, gaseous dielectrics, flame suppression, solvents, cleaners, local anesthetics, and intumescent applications.

50. The method of claim 47, wherein The product is selected from a heat transfer device, a sprayable composition, a solvent, or a mechanical power generation device.

51. The method of claim 50, wherein: The product is a heat transfer device.

52. The method of claim 51, wherein The heat transfer device is a residential or commercial air conditioning system, a heat pump, or a commercial or industrial refrigeration system.

53. The method of claim 47, wherein: The existing compound or composition is a heat transfer composition.

54. The method of claim 53, wherein the heat transfer composition is a refrigerant selected from the group consisting of R-410A, R-454B, R-452B, and R-32.

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