Heat transfer compounds as a replacement for R-134A

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the use of heat transfer compositions comprising 2,3,3,3-tetrafluoropropene and a polyol ester lubricant, particularly in the context of replacing heat transfer compositions based on 1,1,1,2-tetrafluoroethane. TECHNICAL BACKGROUND

[0002] The problems posed by substances that deplete the atmospheric ozone layer were addressed in Montreal, where the protocol imposing a reduction in the production and use of chlorofluorocarbons (CFCs) was signed. This protocol was amended to require the abandonment of CFCs and extend the regulation to other products, including hydrochlorofluorocarbons (HCFCs).

[0003] The refrigeration and air conditioning industry has invested heavily in replacing CFC and HCFC refrigerants, and this is how hydrofluorocarbons (HFCs), which are of little or no harm to the ozone layer, have been commercialized.

[0004] In particular, 1,1,1,2-tetrafluoroethane (HFC-134a) is an example of an HFC that has seen very widespread use, for example in automotive air conditioning.

[0005] However, many HFC refrigerants, including HFC-134a, can contribute negatively to the greenhouse effect. This contribution is quantified by a numerical parameter, the GWP (Global Warming Potential).

[0006] Hydrofluoroolefins (HFOs) such as 2,3,3,3-tetrafluoropropene (HFO-1234yf) or 1,3,3,3-tetrafluoropropene (HFO-1234ze) are low GWP fluids that are likely to be used in heat transfer applications.

[0007] In most applications, heat transfer fluids are used in vapor compression circuits. The fluid undergoes evaporation, followed by compression, condensation, and expansion to complete the cycle.

[0008] The use of a lubricant (or lubricating oil) is generally necessary to ensure the proper functioning of the moving mechanical parts in the circuit, and in particular to ensure the lubrication of the compressor bearings.

[0009] Polyol esters (POEs) in particular have been proposed as possible lubricants for HFOs.

[0010] WO 2009 / 124128 describes a method for selecting a heat transfer fluid and a lubricant for a vapor compression system.

[0011] WO 2010 / 083100 describes heat transfer compositions comprising carbon dioxide and a POE-based lubricant.

[0012] The article Analysis of LGWP Alternatives for Small Refrigeration (Plugin) Applications, by Yana Motta et al., in the International Refrigeration and Air Conditioning Conference at Purdue (2010) compares the efficiency of HFO-1234yf and HFO-1234ze in small refrigeration systems.

[0013] Document US 2012 / 024007 describes a compressor for refrigeration or air conditioning charged with a heat transfer fluid which may be, among others, HFO-1234yf, and a lubricant comprising POE.

[0014] WO 2012 / 001255 describes compositions comprising a POE-based lubricant and a heat transfer fluid containing at least 99.8% by weight of HFO-1234yf.

[0015] US 8,685,271 describes a group of POEs and their use with various possible heat transfer fluids.

[0016] Document FR 2964975 describes a composition comprising a POE or PVE lubricant and a heat transfer fluid of 1-99% by weight of HFO-1234yf and 1-99% by weight trans-HFO-1234ze.

[0017] Document WO 2018 / 069621 describes the use of a composition comprising a POE lubricant and a fluid F comprising at least one tetrafluoropropene and at least one hydrofluorocarbon in a vapor compression circuit comprising an oil separator.

[0018] US 2016 / 333241 describes the replacement of R-410A with an unsaturated hydrofluorocarbon with a lubricant having special properties such as voltage breakdown and OH value.

[0019] The article by Navarro et al. in the Journal of Refrigeration, Elsevier vol. 3, no. 3, November 24, 2012, describes a comparative experimental study on an open-system compressor operating with HFO-1234yf, HFC-134a, and propane.

[0020] The article Lubricant Development To Meet Lower GWP Refrigerant Challenges, by JA Karnaz, in the 15th International Refrigeration and Air Conditioning Conference at Purdue (2014) focuses on the evaluation of lubricants for so-called next-generation heat transfer fluids, including HFO-1234ze.

[0021] The article Convection-driven Absorption of R-1234yf in Lubricating Oil, by Neto et al. in International Journal of Refrigeration 44:151-160 (2014) describes the determination of the absorption rate of HFO-1234yf across the surface of a POE ISO VG 10 lubricant layer in a closed system.

[0022] EP 2947136 describes a lubricating oil comprising a base oil, a sulfide compound and a gallate. The base oil may in particular be POE. This lubricating oil may be used, among other things, with HFO-1234yf.

[0023] The article Evaluating Lubricants for Lower GWP Refrigerant Compressor Operation, by JA Karnaz, in the 16th International Refrigeration and Air Conditioning Conference at Purdue (2015) focuses on the evaluation of lubricants for a range of heat transfer fluids, including in particular blends containing HFOs.

[0024] US 2016 / 053153 describes heat transfer compositions comprising a tetrafluoropropene and a POE-based lubricant.

[0025] WO 2016 / 209560 describes heat transfer compositions comprising a fluorinated olefin and a POE-based lubricant having a kinematic viscosity at 40°C of 150 to 360 cSt.

[0026] There is still a need to provide efficient heat transfer processes, particularly in the context of efficient substitution of HFC-134a-based heat transfer compositions with low GWP heat transfer compositions. SUMMARY OF THE INVENTION

[0027] The invention relates firstly to a method of transferring heat by means of a heat transfer installation using a scroll compressor and containing a heat transfer composition, the heat transfer composition comprising: a refrigerant, which includes 2,3,3,3-tetrafluoropropene, and a lubricant; wherein the lubricant comprises a polyol ester, the solubility of 2,3,3,3-tetrafluoropropene in the lubricant at 0°C and at an absolute pressure of 2.2 bar being lower than the solubility of 1,1,1,2-tetrafluoroethane in the lubricant at 0°C and at an absolute pressure of 2.0 bar; the method comprising the successive steps of: evaporating a refrigerant; superheating the refrigerant from 1 to 10°C; compressing the refrigerant.

[0028] In some embodiments, the superheat of the refrigerant is preferably 2 to 10°C, more preferably 3 to 5°C.

[0029] In some embodiments, the lubricant comprises a dipentaerythritol ester.

[0030] In some embodiments, the lubricant has a kinematic viscosity at 40°C of 10 to 200 cSt, preferably 20 to 100 cSt, and more preferably 30 to 80 cSt.

[0031] In some embodiments, the method is a mobile or stationary air conditioning and / or heating, refrigeration, freezing or deep freezing method.

[0032] In some embodiments, the evaporation of the refrigerant is carried out at an average temperature less than or equal to 10°C, preferably less than or equal to 0°C, more preferably less than or equal to -10°C.

[0033] In some embodiments, the heat transfer facility is a facility intended to operate with an initial heat transfer composition comprising: an initial refrigerant, and an initial lubricant, the initial heat transfer composition being different from the heat transfer composition used in the process.

[0034] In some embodiments, said heat transfer composition is a replacement heat transfer composition, which is used as a replacement for an initial heat transfer composition comprising: an initial refrigerant, and an initial lubricant.

[0035] In some embodiments, the superheat with the replacement heat transfer composition is less than or equal to the superheat when the same method is carried out with the initial heat transfer composition; and preferably the superheat with the replacement heat transfer composition is at least 2°C, preferably at least 5°C, more preferably at least 10°C, lower than the superheat when the same method is carried out with the initial heat transfer composition.

[0036] In some embodiments, the lubricant of the replacement heat transfer composition is identical to the initial lubricant.

[0037] In some embodiments, the lubricant of the replacement heat transfer composition is different from the initial lubricant.

[0038] In some embodiments, the lubricant of the replacement heat transfer composition has a kinematic viscosity at 40°C less than or equal to the kinematic viscosity at 40°C of the initial lubricant, the difference between the kinematic viscosity at 40°C of the initial lubricant and the kinematic viscosity at 40°C of the lubricant of the replacement heat transfer composition preferably being greater than or equal to 5 cSt, more preferably greater than or equal to 10 cSt.

[0039] In some embodiments, the initial lubricant comprises a polyol ester, and preferably comprises a dipentaerythritol ester.

[0040] In some embodiments, the initial refrigerant comprises 1,1,1,2-tetrafluoroethane or consists essentially of 1,1,1,2-tetrafluoroethane.

[0041] The present invention makes it possible to meet the need expressed above. More particularly, it provides efficient heat transfer methods, in particular in the context of an efficient substitution of HFC-134a-based heat transfer compositions with low GWP heat transfer compositions.

[0042] The invention is based on the observation that HFO-1234yf is relatively poorly soluble in certain POE oils (and in particular in POE oils of the same type as POE ISO 55 oil), i.e. less soluble than HFO-1234ze and the reference fluid HFC-134a.

[0043] The use of such oils in combination with HFO-1234yf makes it possible to replace heat transfer compositions comprising HFC-134a particularly effectively in heat transfer processes involving superheating after evaporation.

[0044] For example, in the context of replacing a composition containing HFC-134a with a composition containing HFO-1234yf, it is possible to obtain the following benefits: a reduction in evaporative superheat during replacement; or a reduction in lubricant viscosity during replacement;

[0045] Il It is of course possible to combine these two aspects.

[0046] In a heat transfer system, the lubricant is mainly present in the compressor, for the lubrication of moving parts. However, a fraction of the lubricant can be carried out of the compressor and thus circulate throughout the entire circuit containing the refrigerant.

[0047] A first benefit of the invention concerns the reduction of overheating when changing the heat transfer composition.

[0048] Superheating the refrigerant after evaporation allows: to limit the presence of liquid refrigerant in the compressor (liquid compression being a major cause of compressor breakdown); to reduce the solubility of the refrigerant in the oil in the compressor and thus avoid foaming and therefore re-compression of the liquid, especially at start-up; to limit the loss of viscosity of the oil when it is in contact with the refrigerant, this loss of viscosity being detrimental to the lubrication of the bearings and moving parts in the compressor; and to facilitate the separation of the refrigerant and the lubricant at the compressor outlet.

[0049] On the other hand, the presence of overheating results in reduced system performance.

[0050] By choosing a POE lubricant in which HFO-1234yf is poorly soluble (compared to the reference fluid HFC-134a), the viscosity of the lubricant is relatively unaffected in the presence of HFO-1234yf in the compressor. This reduces overheating, and thus increases performance, without adversely affecting foam prevention, lubrication, or the separation of the lubricant and refrigerant.

[0051] The reduction in overheating is particularly beneficial when the process is implemented for air conditioning.

[0052] A second benefit of the invention concerns the use of an oil of lower viscosity, in order to reduce the friction forces on the compressor bearings compared to a reference oil, especially in areas where the oil is not mixed with the refrigerants. However, the power consumed per lubrication bearing is proportional to the viscosity of the lubricant.

[0053] Reducing the viscosity of the oil also improves lubrication when the installation is started (which can help limit energy consumption linked to heating the compressor during this start-up); and limits pressure losses in the circuit and therefore reduces energy consumption linked to pumping.

[0054] Thus, an object of the invention is the use, as a replacement heat transfer composition, of a composition comprising: a replacement refrigerant comprising 2,3,3,3-tetrafluoropropene, and a replacement lubricant comprising a polyol ester; in place of an initial heat transfer composition comprising: an initial refrigerant comprising 1,1,1,2-tetrafluoroethane, and an initial lubricant; in a heat transfer process comprising the successive steps of: evaporating a refrigerant; superheating the refrigerant; compressing the refrigerant; wherein the superheat when the process is carried out with the replacement heat transfer composition is less than the superheat when the process is carried out with the initial heat transfer composition.

[0055] Another object of the invention is the use, as a replacement heat transfer composition, of a composition comprising: a replacement refrigerant comprising 2,3,3,3-tetrafluoropropene and a replacement lubricant comprising a polyol ester; in place of an initial heat transfer composition comprising: an initial refrigerant comprising 1,1,1,2-tetrafluoroethane and an initial lubricant; in a heat transfer process; the replacement lubricant having a kinematic viscosity at 40°C lower than the kinematic viscosity at 40°C of the initial lubricant. BRIEF DESCRIPTION OF THE FIGURES

[0056] There figure 1 represents the pressure at the compressor inlet (in bar, on the ordinate) as a function of the temperature at the compressor inlet (in °C, on the abscissa), for three refrigerant / lubricant mixtures A, B and C as described in more detail in the examples section. There figure 2represents the pressure at the compressor inlet (in bar, on the ordinate) as a function of the temperature at the compressor inlet (in °C, on the abscissa), for three refrigerant / lubricant mixtures D, E and F as described in more detail in the examples section. There figure 3 represents the kinematic viscosity (in cSt, on the ordinate) as a function of the temperature at the compressor inlet (in °C, on the abscissa), for three refrigerant / lubricant mixtures A, B and C as described in more detail in the examples section. DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0057] The invention is now described in more detail and in a non-limiting manner in the following description. Unless otherwise stated, throughout the application, the proportions of compounds indicated are given in mass percentages.

[0058] The invention relates to a heat transfer method carried out by means of a heat transfer installation. The installation contains a heat transfer composition.

[0059] In some embodiments, the heat transfer installation was originally designed to operate with another heat transfer composition, called the initial heat transfer composition (and in particular with another refrigerant, called the initial refrigerant).

[0060] In certain embodiments, the heat transfer composition used in the method of the invention is a so-called replacement heat transfer composition, that is to say that the same heat transfer installation was previously used to implement a heat transfer method with another heat transfer composition, called the so-called initial heat transfer composition.

[0061] The two preceding paragraphs correspond to the hypothesis of a replacement.

[0062] In this case, the initial heat transfer composition consists of a so-called initial refrigerant, a so-called initial lubricant, and possible additives.

[0063] The replacement heat transfer composition consists of a so-called replacement refrigerant, a so-called replacement lubricant, and possible additives.

[0064] By " refrigerant " Or "heat transfer fluid", means a fluid capable of absorbing heat by evaporating at low temperature and low pressure and of rejecting heat by condensing at high temperature and high pressure, in a vapor compression circuit, depending on the application considered. Generally speaking, a refrigerant fluid can consist essentially of a single compound or be a mixture of several compounds.

[0065] The replacement refrigerant is different from the original refrigerant.

[0066] In some embodiments, the replacement lubricant is identical to the initial lubricant.

[0067] In other embodiments, the replacement lubricant is different from the initial lubricant.

[0068] The term "lubricant" is used synonymously with "lubricating oil" " Or " oil ".

[0069] In certain embodiments, the method of the invention successively comprises: an implementation with the initial heat transfer composition; replacement of the initial heat transfer composition with the replacement heat transfer composition; and an implementation with the replacement heat transfer composition.

[0070] In other embodiments, the installation is directly implemented with the replacement heat transfer composition, without being implemented with the initial heat transfer composition - even though it is, by its original design, adapted to operate with the initial heat transfer composition.

[0071] This hypothesis is, by extension, also considered a case of " replacement " within the meaning of the invention. Overview of the heat transfer process

[0072] The heat transfer method of the invention is implemented in a heat transfer installation. The heat transfer installation comprises a vapor compression system. The system contains a heat transfer composition, which ensures the heat transfer.

[0073] In some embodiments, the installation contains: initially, the initial heat transfer composition; then, after replacement, the replacement heat transfer composition.

[0074] The heat transfer process can be a process of heating or cooling a fluid or a body.

[0075] In some embodiments, the vapor compression system is: an air conditioning system; or a refrigeration system; or a freezing system; or a heat pump system.

[0076] The installation can be mobile or stationary.

[0077] Thus, the heat transfer process may be a stationary air conditioning process (in residential premises or in industrial or commercial premises), or mobile air conditioning, in particular automotive, a stationary refrigeration process, or mobile refrigeration (for example refrigerated transport), or a stationary freezing or deep-freezing process, or mobile freezing or deep-freezing (for example refrigerated transport), or a stationary heating process, or mobile heating (for example automotive).

[0078] The heat transfer process advantageously comprises the following steps, implemented cyclically: the evaporation of the refrigerant in an evaporator; the compression of the refrigerant in a compressor; the condensation of the refrigerant in a condenser; and the expansion of the refrigerant in an expansion module.

[0079] Refrigerant evaporation can be carried out from a liquid phase or a two-phase liquid / vapor phase.

[0080] The compressor can be hermetic, semi-hermetic, or open. Hermetic compressors comprise a motor section and a compression section that are enclosed in a non-disassemblable hermetic enclosure. Semi-hermetic compressors comprise a motor section and a compression section that are directly assembled against each other. The coupling between the motor section and the compression section is accessible by disassembling the two parts. Open compressors comprise a motor section and a compression section that are separate. They can operate by belt drive or direct coupling.

[0081] In the installation that is used, the compressor can be driven by an electric motor or by a gas turbine (for example powered by the exhaust gases of a vehicle, for mobile applications) or by gearing.

[0082] The evaporator and condenser are heat exchangers. Il It is possible to use any type of heat exchanger in the invention, and in particular co-current heat exchangers or, preferably, counter-current heat exchangers.

[0083] By " counter-current heat exchanger”, means a heat exchanger in which heat is exchanged between a first fluid and a second fluid, the first fluid at the inlet of the exchanger exchanging heat with the second fluid at the outlet of the exchanger, and the first fluid at the outlet of the exchanger exchanging heat with the second fluid at the inlet of the exchanger.

[0084] For example, counterflow heat exchangers include devices in which the flow of the first fluid and the flow of the second fluid are in opposite, or nearly opposite, directions. Exchangers operating in crossflow mode with a counterflow tendency are also included among counterflow heat exchangers.

[0085] The installation may also optionally include at least one heat transfer fluid circuit used to transport heat (with or without change of state) between the circuit of the heat transfer composition and the fluid or body to be heated or cooled.

[0086] The installation may also optionally include two (or more) vapor compression circuits, containing identical or distinct heat transfer compositions. For example, the vapor compression circuits may be coupled together.

[0087] According to the invention, the refrigerant is superheated between evaporation and compression, that is to say it is brought to a temperature higher than the end of evaporation temperature, between evaporation and compression.

[0088] By “start of evaporation temperature”, we hear the temperature of the refrigerant at the inlet of the evaporator.

[0089] By "end of evaporation temperature", we mean the temperature of the refrigerant when the last drop of refrigerant evaporates in liquid form (saturated vapor temperature or dew point temperature).

[0090] When the refrigerant is a pure body or an azeotropic mixture, the evaporation start temperature is equal to the evaporation end temperature.

[0091] By "average evaporation temperature", we mean the arithmetic mean between the temperature at the start of evaporation and the temperature at the end of evaporation.

[0092] We designate by "overheating"(equivalent here to "evaporator overheating") the temperature differential between the maximum temperature reached by the refrigerant before compression (i.e. the maximum temperature reached by the refrigerant at the end of the superheating step) and the end of evaporation temperature. This maximum temperature is generally the temperature of the refrigerant at the compressor inlet. It may correspond to the temperature of the refrigerant at the evaporator outlet. Alternatively, the refrigerant may be at least partly superheated between the evaporator and the compressor (for example by means of an internal exchanger). The superheating may be adjusted by appropriate adjustment of the installation parameters, and in particular by adjustment of the expansion module. In the method of the invention, the superheating is strictly greater than 0°C.

[0093] The expansion module can be a thermostatic valve called a thermostatic or electronic expansion valve with one or more ports, or a pressure-controlled expansion valve that regulates the pressure. It can also be a capillary tube in which the fluid is expanded by the pressure drop in the tube. The expansion module can also be a turbine to produce mechanical work (which can be converted into electricity), or a turbine coupled directly or indirectly to the compressor.

[0094] In some embodiments, the invention provides for replacing an initial heat transfer composition with a replacement heat transfer composition in the heat transfer process.

[0095] In some embodiments, this replacement may be accomplished by emptying, preferably completely or substantially completely, the initial refrigerant from the installation, and introducing the replacement refrigerant in place thereof, into the installation - and this without emptying (or without completely emptying) the initial lubricant. In this case, the replacement lubricant may be the initial lubricant itself.

[0096] In some embodiments, this replacement may be accomplished by emptying, preferably all or substantially all, the initial heat transfer composition from the facility, and introducing the replacement heat transfer composition in place thereof into the facility. In this case, preferably the replacement lubricant is different from the initial lubricant.

[0097] It is considered that the " even "method is implemented, with the initial heat transfer composition on the one hand, and with the replacement heat transfer composition on the other hand.

[0098] Preferably, before and after replacement, the process works like this: with the same average evaporation temperature; and with the same average condensation temperature.

[0099] Neither the compressor, nor the heat exchangers, nor the expansion module are replaced during the replacement.

[0100] The setting of these elements can optionally be changed upon replacement, to ensure that the average evaporating and condensing temperatures remain the same.

[0101] In some embodiments, only the expansion module setting is changed.

[0102] In other embodiments, no settings are changed.

[0103] The average condensation temperature is defined as the arithmetic mean between the condensation start temperature (temperature of the refrigerant in the condenser when the first liquid drop of refrigerant appears, called the vapor saturation temperature or dew point temperature) and the condensation end temperature (temperature of the refrigerant when the last bubble of refrigerant condenses in gaseous form, called the liquid saturation temperature or bubble temperature).

[0104] We designate by "subcooling"the possible temperature differential (in absolute value) between the minimum temperature reached by the refrigerant before expansion and the end of condensation temperature. Generally, this minimum temperature corresponds to the temperature of the refrigerant at the inlet of the expansion module. It may correspond to the temperature of the refrigerant at the outlet of the condenser. Alternatively, the refrigerant may be at least partially subcooled between the condenser and the expansion module (for example by means of an internal exchanger).

[0105] Preferably, in the process of the invention, subcooling (strictly above 0°C) is applied, preferably subcooling of 1 to 15°C, more preferably of 2 to 12°C and more preferably of 5 to 10°C.

[0106] The invention is particularly useful when the average evaporation temperature is less than or equal to 10°C; or less than or equal to 5°C; or less than or equal to 0°C; or less than or equal to -5°C; or less than or equal to -10°C.

[0107] Thus, the invention is particularly useful for implementing a low temperature refrigeration, or moderate temperature cooling, or moderate temperature heating method.

[0108] In processes of " low temperature refrigeration”, the average evaporation temperature is preferably from -45°C to -15°C, in particular from -40°C to -20°C, more particularly preferably from -35°C to -25°C and for example approximately -30°C; and the average condensation temperature is preferably from 25°C to 80°C, in particular from 30°C to 60°C, more particularly preferably from 35°C to 55°C and for example approximately 40°C. These methods include in particular freezing and deep-freezing methods.

[0109] In processes of “cooling at moderate temperature”, the average evaporation temperature is preferably from -20°C to 10°C, in particular from -15°C to 5°C, more particularly preferably from -10°C to 0°C and for example approximately -5°C; and the average condensation temperature is preferably from 25°C to 80°C, in particular from 30°C to 60°C, more particularly preferably from 35°C to 55°C and for example approximately 50°C. These processes may in particular be refrigeration or air conditioning processes.

[0110] In processes of " heating at moderate temperature”, the average evaporation temperature is preferably from -20°C to 10°C, in particular from -15°C to 5°C, more particularly preferably from -10°C to 0°C and for example approximately -5°C; and the average condensation temperature is preferably from 25°C to 80°C, in particular from 30°C to 60°C, more particularly preferably from 35°C to 55°C and for example approximately 50°C. Refrigerants

[0111] When the invention is applied to the replacement of an initial heat transfer composition, the initial refrigerant may be any refrigerant, for example a refrigerant comprising a CFC, or an HCFC, or an HFC. The initial refrigerant may in particular have a GWP greater than or equal to 150, or greater than or equal to 500, or greater than or equal to 1000.

[0112] In some embodiments, the initial refrigerant comprises HFC-134a.

[0113] In some embodiments, the initial refrigerant comprises at least 10% HFC-134a, or at least 20% HFC-134a, or at least 30% HFC-134a, or at least 40% HFC-134a, or at least 50% HFC-134a, or at least 60% HFC-134a, or at least 70% HFC-134a, or at least 80% HFC-134a, or at least 90% HFC-134a, or at least 95% HFC-134a, based on the total mass of the initial refrigerant.

[0114] In some embodiments, the initial refrigerant consists essentially of, or consists of, HFC-134a (excluding impurities).

[0115] In other embodiments, the initial refrigerant comprises HFC-134a in admixture with one or more heat transfer compounds, and preferably one or more hydrofluorocarbons and / or hydrocarbons.

[0116] By "hydrofluorocarbons", within the scope of this application, saturated hydrofluorocarbons, which are not hydrofluoroolefins, are understood to mean.

[0117] Examples of hydrofluorocarbons include difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1-trifluoropropane (HFC-263fb), and mixtures thereof.

[0118] Preferably, the initial refrigerant is free of hydrofluoroolefins and hydrochlorofluoroolefins.

[0119] In some embodiments, the initial refrigerant is a binary (consisting of two compounds) or ternary (consisting of three compounds) or quaternary (consisting of four compounds) or quinquenary (consisting of five compounds) composition.

[0120] Examples of blends that can be used as the initial refrigerant are R-407A, R-407B, R-407C, R-407D, R-407E, R-407F, R-421A, R-421B, R-422A, R-422B, R-422C, R-422D, R-424A, R-425A, R-426A, and R-427A.

[0121] Impurities may or may not be present in such refrigerants. When present, they may represent less than 1%, preferably less than 0.5%, preferably less than 0.1%, preferably less than 0.05% and preferably less than 0.01% (by mass) of said fluid.

[0122] The refrigerant used to carry out the method of the invention, which is the replacement refrigerant if a replacement is made, comprises HFO-1234yf.

[0123] In some embodiments, this refrigerant comprises at least 10% HFO-1234yf, or at least 20% HFO-1234yf, or at least 30% HFO-1234yf, or at least 40% HFO-1234yf, or at least 50% HFO-1234yf, or at least 60% HFO-1234yf, or at least 70% HFO-1234yf, or at least 80% HFO-1234yf, or at least 90% HFO-1234yf, or at least 95% HFO-1234yf, based on the total mass of the replacement refrigerant.

[0124] In some embodiments, this refrigerant consists essentially of, or consists of, HFO-1234yf (excluding impurities).

[0125] In other embodiments, this refrigerant comprises HFO-1234yf in admixture with one or more hydrofluorocarbons and / or hydrofluoroolefins and / or hydrocarbons and / or hydrochlorofluoroolefins and / or CO 2 .

[0126] Among the hydrofluoroolefins, we can cite in particular HFO-1234ze, in cis and / or trans form, and preferably in trans form; and trifluoroethylene (HFO-1123).

[0127] Among the hydrochlorofluoroolefins, mention may be made in particular of 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), in cis and / or trans form, and preferably in trans form.

[0128] Examples of hydrofluorocarbons include difluoromethane (HFC-32), pentafluoroethane (HFC-125), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea), 1,1,1-trifluoropropane (HFC-263fb) and mixtures thereof.

[0129] In some embodiments, this refrigerant is a binary (consisting of two compounds) or ternary (consisting of three compounds) or quaternary (consisting of four compounds) or quinquenary (consisting of five compounds) composition.

[0130] Impurities may or may not be present in such refrigerants. When present, they may represent less than 1%, preferably less than 0.5%, preferably less than 0.1%, preferably less than 0.05% and preferably less than 0.01% (by mass) of said fluid.

[0131] In addition to HFO-1234yf alone (except for impurities), refrigerants which may be used for the process of the invention (and therefore, where appropriate, as replacement refrigerants) are those consisting of (except for impurities): you HFO-1234yf and you HFC-32; you HFO-1234yf and you HFC-152a; you HFO-1234yf and you HFC-134a; you HFO-1234yf and you HFC-134; you HFO-1234yf and you HFO-1123; you HFO-1234yf and you HFC-125; you HFO-1234yf and you CO 2; you HFO-1234yf, you HFC-32 and you CO 2; you HFO-1234yf, you HFC-32 and you HFO-1123; you HFO-1234yf, you HFC-125 and you HFO-1123; you HFO-1234yf, you HFC-134a and you HFO-1123; you HFO-1234yf, you HFC-134 and you HFO-1123 ; you HFO-1234yf, you HFC-32 and you HFC-125 ; you HFO-1234yf, you HFC-152a and you HFC-125 ; you HFO-1234yf, you HFC-152a and you HFC-32 ; you HFO-1234yf, you HFC-134a and you HFC-152a ; you HFO-1234yf, you HFC-134a and you HFC-32 ; you HFO-1234yf, you HFC-134a and you HFC-125 ; you HFO-1234yf, you HFC-1234ze and you HFC-134a ; you HFO-1234yf, you HFO-1234ze and you HFC-152a ; you HFO-1234yf, you HFO-1234ze and you HFC-134 ; you HFO-1234yf, you HFO-1234ze and you HFC-32 ; you HFO-1234yf, you HFO-1234ze and you HFC-125 ; you HFO-1234yf, you HFC-134a, you HFC-125 and you HFC-32 ;you HFO-1234yf, you HFO-1234ze, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-152a, you HFC-125 and you HFC-32 ; you HFO-1234yf, you CO 2 , you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-134, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-227ea, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-134a, you HFC-152a and you HFC-32 ; you HFO-1234yf, you HFC-134a, you HFC-152a and you HFC-125 ; you HFO-1234yf, you HFO-1234ze, you HFC-152a and you HFC-32 ; you HFO-1234yf, you HFO-1234ze, you HFC-134a and you HFC-32 ; you HFO-1234yf, you HFO-1234ze, you HFC-134a and you HFC-152a ; you HFO-1234yf, you HFO-1234ze, you HFC-134a and you HFC-125 ; you HFO-1234yf, you HFC-134a, you HFC-152a, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-134a, you HFC-1234ze, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-134a, you HFC-227ea, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-134a, you CO2, you HFC-125 and you HFC-32 ; you HFO-1234yf, you HFC-134a, you HFC-134, you HFC-125 and you HFC-32. ;

[0132] Preferred refrigerants include those consisting of (excluding impurities): HFO-1234yf and HFC-32 in respective mass proportions of 60 to 85% and 15 to 40%; or preferably 63 to 79% and 21 to 37%; or more preferably 64 to 79% and 21 to 36%; HFO-1234yf and HFC-152a in respective mass proportions of 10 to 95% and 5 to 90%; or preferably 50 to 95% and 5 to 50%; or more preferably 80 to 95% and 5 to 20%; HFO-1234yf and HFC-134a in respective mass proportions of 10 to 95% and 5 to 90%; or preferably 40 to 60% and 40 to 60%; or more preferably 50 to 60% and 40 to 50%; of HFO-1234yf and HFC-125 in respective mass proportions of 10 to 95% and 5 to 90%; or preferably 50 to 95% and 5 to 50%; or more preferably 80 to 95% and 5 to 20%; of HFO-1234yf, HFC-134a and HFC-152a in respective mass proportions of 1 to 98%, 1 to 98% and 1 to 98%; or preferably 50 to 98%, 1 to 49% and 1 to 49%;or more preferably from 56 to 80%, from 5 to 22% and from 5 to 22%. of HFO-1234yf, HFC-125 and HFC-32 in respective mass proportions of 1 to 98%, from 1 to 98% and from 1 to 98%; or more preferably from 1 to 49%, from 1 to 49% and from 50 to 98%; or more preferably from 20 to 30%, from 1 to 10% and from 60 to 75%. of HFO-1234yf, CO 2 and HFC-32 in respective mass proportions of 1 to 98%, from 1 to 98% and from 1 to 98%; or more preferably from 50 to 98%, from 1 to 49% and from 1 to 49%; or preferably still from 70 to 80%, from 1 to 10% and from 5 to 22%.;

[0133] In some embodiments, the refrigerant of the invention (where applicable, replacement refrigerant) consists of (excluding impurities): from 74 to 81.5% (preferably from 75.5 to 79.5%) of HFO-1234yf, from 12 to 16% of HFC-152a, and from 6.5 to 10.5% of HFC-134a (by mass). Such a refrigerant has the advantage of being azeotropic.

[0134] In some embodiments, the refrigerant of the invention (if applicable, replacement refrigerant) consists of (excluding impurities) about 77.5% HFO-1234yf, about 14% HFC-152a, and about 8.5% HFC-134a (by mass). Such a refrigerant has the advantage of being azeotropic.

[0135] In some embodiments, the refrigerant of the invention (if applicable, replacement refrigerant) consists of (excluding impurities) about 77.5% HFO-1234yf, about 16% HFC-152a, and about 6.5% HFC-134a (by mass). Such a refrigerant has the advantage of being azeotropic.

[0136] In some embodiments, the refrigerant of the invention (if applicable, replacement refrigerant) consists of (excluding impurities) about 81.5% HFO-1234yf, about 12% HFC-152a, and about 6.5% HFC-134a (by mass). Such a refrigerant has the advantage of being azeotropic.

[0137] In some embodiments, the refrigerant of the invention (if applicable, replacement refrigerant) consists of (excluding impurities) about 75.5% HFO-1234yf, about 14.5% HFC-152a and about 10% HFC-134a (by mass). Such a refrigerant has the advantage of being azeotropic.

[0138] In some embodiments, the refrigerant of the invention (if applicable, replacement refrigerant) consists of (excluding impurities) about 77.5% HFO-1234yf, about 12% HFC-152a, and about 10.5% HFC-134a (by mass). Such a refrigerant has the advantage of being azeotropic.

[0139] The GWP of the refrigerant used in the process of the invention (which where appropriate is the replacement refrigerant) is preferably less than 1000, more preferably less than 500, or 150, or 100, or 50, or 25.

[0140] When a replacement is made, preferably the GWP of the replacement refrigerant is lower than the GWP of the original refrigerant.

[0141] GWP is defined relative to carbon dioxide and relative to a 100-year time horizon, according to the method given in "The scientific assessment of ozone depletion, 2002, a report of the World Meteorological Association's Global Ozone Research and Monitoring Project ».

[0142] When a substitution is made, in some embodiments, HFC-134a (alone) is replaced with HFO-1234yf (alone).

[0143] When a replacement is made, in some embodiments, an initial refrigerant comprising HFC-134a in admixture with one or more other compounds is replaced with a replacement refrigerant comprising HFO-1234yf in admixture with the same other compound(s).

[0144] Preferably, if HFC-134a is present in the replacement refrigerant, the mass proportion of HFC-134a in the replacement refrigerant is less than the mass proportion of HFC-134a in the initial refrigerant.

[0145] Preferably, if one or more hydrofluorocarbons are present in the replacement refrigerant, the mass proportion of all the hydrofluorocarbons in the replacement refrigerant is less than the mass proportion of all the hydrofluorocarbons in the initial refrigerant. Lubricant

[0146] The heat transfer composition used for implementing the method comprises a lubricant (so-called replacement lubricant, when a replacement is carried out).

[0147] This lubricant comprises a POE. Preferably, the lubricant is a POE. Alternatively, it may be a mixture of POE and another product such as a PAG.

[0148] In the above, by " a POE ", we mean either a single POE or preferably a mixture of several POEs.

[0149] A POE can be obtained by reacting at least one polyol (i.e. compound containing at least two OH groups) with at least one carboxylic acid.

[0150] POEs suitable for use in the present invention include POE types A, B, C and D described in more detail below.

[0151] POEs of type A correspond to the following formula (I): (I) R 1< [OC(O)R 2< ] n in which: R 1< is a linear or branched hydrocarbon radical, optionally substituted by at least one hydroxyl group and / or comprising at least one heteroatom chosen from the group consisting of O, N, and S; each R 2< is, independently, selected from the group consisting of: i) H; ii) an aliphatic hydrocarbon radical; iii) a branched hydrocarbon radical; iv) a mixture of a radical ii) and / or iii), with an aliphatic hydrocarbon radical comprising from 8 to 14 carbon atoms; and n is an integer of at least 2.

[0152] In the context of the invention, the term “term” means: "hydrocarbon radical" a radical composed of carbon and hydrogen atoms.

[0153] In certain embodiments, the polyols used to obtain the POEs of type A correspond to the following formula (II): (II) R 1 < (OH) n in which: R 1< is a linear or branched hydrocarbon radical, optionally substituted by at least one hydroxyl group, preferably by two hydroxyl groups, and / or comprising at least one heteroatom chosen from the group consisting of O, N, and S; and n is an integer of at least 2.

[0154] In certain embodiments, R 1< is a linear or branched hydrocarbon radical comprising from 4 to 40 carbon atoms, preferably from 4 to 20 carbon atoms.

[0155] In certain embodiments, R 1< is a linear or branched hydrocarbon radical comprising at least one oxygen atom.

[0156] In some embodiments, R 1< is a branched hydrocarbon radical comprising from 4 to 10 carbon atoms, preferably 5 carbon atoms, substituted by two hydroxyl groups.

[0157] In some embodiments, the polyols comprise from 2 to 10 hydroxyl groups, preferably from 2 to 6 hydroxyl groups.

[0158] Polyols can contain one or more oxyalkylene groups; in this particular case, they are polyether polyols.

[0159] The polyols may also include one or more nitrogen atoms. For example, the polyols may be alkanol amines containing from 3 to 6 hydroxyl groups. In some embodiments, the polyols are alkanol amines containing at least two hydroxyl groups, and preferably at least three.

[0160] In some embodiments, the polyols are selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, glycerol, neopentyl glycol, 1,2-butanediol, 1,4-butanediol, 1,3-butanediol, pentaerythritol, dipentaerythritol, tripentaerythritol, triglycerol, trimethylolpropane, sorbitol, hexaglycerol, and mixtures thereof.

[0161] In certain embodiments, the carboxylic acids used to obtain the POEs of type A correspond to the following formula (III): (III) R 2 < COOH in which: R 2< is selected from the group consisting of: i) H; ii) an aliphatic hydrocarbon radical; iii) a branched hydrocarbon radical; iv) a mixture of a radical ii) and / or iii), with an aliphatic hydrocarbon radical comprising from 8 to 14 carbon atoms.

[0162] In certain embodiments, R 2< is an aliphatic hydrocarbon radical comprising from 1 to 10, preferably from 1 to 7 carbon atoms, and in particular from 1 to 6 carbon atoms.

[0163] In certain embodiments, R 2< is a branched hydrocarbon radical comprising from 4 to 20 carbon atoms, in particular from 5 to 14 carbon atoms, and preferably from 6 to 8 carbon atoms.

[0164] In some embodiments, a branched hydrocarbon radical as mentioned above has the following formula (IV): (IV) -C(R 3< )(R 4< )(R 5< ) wherein R 3< , R 4< and R 5< are, independently of each other, an alkyl group, and at least one of the alkyl groups contains at least two carbon atoms. Such branched alkyl groups, once bonded to the carboxyl group, are known as " neo group",and the corresponding acid as “neo acid”. Preferably, R 3< and R 4< are methyl groups and R 5< is an alkyl group comprising at least two carbon atoms.

[0165] The radical R 2< may comprise one or more carboxy groups, or ester groups such as -COOR 6< , with R 6< representing an alkyl, hydroxyalkyl or hydroxyalkyloxy alkyl radical.

[0166] In some embodiments, the acid R 2 < COOH of formula (III) is a monocarboxylic acid.

[0167] Examples of carboxylic acids in which the hydrocarbon radical is aliphatic include: formic acid, acetic acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid and heptanoic acid.

[0168] Examples of carboxylic acids in which the hydrocarbon radical is branched include: 2-ethyl-n-butyric acid, 2-hexyldecanoic acid, isostearic acid, 2-methylhexanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, 3,5,5-trimethylhexanoic acid, 2-ethylhexanoic acid, neoheptanoic acid, and neodecanoic acid.

[0169] Other carboxylic acids that can be used in the preparation of type A POEs are carboxylic acids comprising an aliphatic hydrocarbon radical comprising 8 to 14 carbon atoms. Examples include: decanoic acid, dodecanoic acid, lauric acid, stearic acid, myristic acid, behenic acid, etc. Dicarboxylic acids include maleic acid, succinic acid, adipic acid, sebacic acid, etc.

[0170] In some embodiments, the carboxylic acids used to prepare the type A POEs comprise a mixture of monocarboxylic and dicarboxylic acids, with the proportion of monocarboxylic acids being the majority. The presence of dicarboxylic acids results in particular in the formation of high viscosity POEs.

[0171] In particular, the reaction of forming type A POEs by reaction between carboxylic acid and polyols is an acid-catalyzed reaction. It is notably a reversible reaction, which can be completed by using a large amount of acid or by removing the water formed during the reaction. The esterification reaction can be carried out in the presence of organic or inorganic acids, such as sulfuric acid, phosphoric acid, etc.

[0172] In some embodiments, the reaction is carried out in the absence of a catalyst.

[0173] The amount of carboxylic acid and polyol in the mixture can be varied depending on the desired results. In the special case where all the hydroxyl groups are esterified, enough carboxylic acid must be added to react with all the hydroxyls.

[0174] In some embodiments, when using mixtures of carboxylic acids, these may react sequentially with the polyols.

[0175] In some embodiments, when using a mixture of carboxylic acids, a polyol first reacts with a carboxylic acid, typically the highest molecular weight carboxylic acid, followed by reaction with the carboxylic acid having an aliphatic hydrocarbon chain.

[0176] In some embodiments, the esters may be formed by reaction between the carboxylic acids (or their anhydride or ester derivatives) with the polyols, in the presence of acids at elevated temperature, while removing the water formed during the reaction. Typically, the reaction may be carried out at a temperature of 75 to 200°C.

[0177] In certain embodiments, the POEs formed may comprise hydroxyl groups that have not all reacted, in which case they are partially esterified POEs.

[0178] In some embodiments, the POEs are obtained from the alcohol pentaerythritol, and a mixture of carboxylic acids: isononanoic acid, at least one acid having an aliphatic hydrocarbon radical comprising from 8 to 10 carbon atoms, and heptanoic acid. The preferred polyol esters are obtained from pentaerythritol, and a mixture of 70% isononanoic acid, 15% of at least one carboxylic acid having an aliphatic hydrocarbon radical comprising from 8 to 10 carbon atoms, and 15% heptanoic acid. For example, Solest 68 oil sold by CPI Engineering Services Inc. may be mentioned.

[0179] Type B POEs comprise at least one ester of one or more branched carboxylic acids comprising at most 8 carbon atoms. The ester is in particular obtained by reacting said branched carboxylic acid with one or more polyols.

[0180] Preferably, the branched carboxylic acid comprises at least 5 carbon atoms. In particular, the branched carboxylic acid comprises from 5 to 8 carbon atoms, and preferably it contains 5 carbon atoms.

[0181] Preferably, the aforementioned branched carboxylic acid does not comprise 9 carbon atoms. In particular, said carboxylic acid is not 3,5,5-trimethylhexanoic acid.

[0182] In some embodiments, the branched carboxylic acid is selected from 2-methylbutanoic acid, 3-methylbutanoic acid, and mixtures thereof.

[0183] In some embodiments, the polyol is selected from the group consisting of neopentyl glycol, glycerol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, and mixtures thereof.

[0184] In some embodiments, the POE are obtained from: i) a carboxylic acid selected from 2-methylbutanoic acid, 3-methylbutanoic acid, and mixtures thereof; and ii) a polyol selected from the group consisting of neopentyl glycol, glycerol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, and mixtures thereof.

[0185] In some embodiments, the POE is the one obtained from: 2-methylbutanoic acid and pentaerythritol; 2-methylbutanoic acid and dipentaerythritol; 3-methylbutanoic acid and pentaerythritol; 3-methylbutanoic acid and dipentaerythritol; or 2-methylbutanoic acid and neopentyl glycol.

[0186] THE POE type C are poly(neopentylpolyol) esters obtained by: (i) reaction of a neopentyl polyol having the following formula (V): wherein: each R independently represents CH 3 , C 2 H 5 or CH 2 OH; p is an integer from 1 to 4; with at least one monocarboxylic acid having from 2 to 15 carbon atoms, and in the presence of an acid catalyst, the molar ratio between carboxyl groups and hydroxyl groups being less than 1:1, to form a partially esterified poly(neopentyl)polyol composition; and ii) reacting the partially esterified poly(neopentyl)polyol composition obtained from step i), with another carboxylic acid having from 2 to 15 carbon atoms, to form the final poly(neopentylpolyol) ester(s) composition.

[0187] Preferably, reaction i) is carried out with a molar ratio ranging from 1:4 to 1:2.

[0188] Preferably, the neopentyl polyol has the following formula (VI): in which each R represents, independently of one another, CH 3 , C 2 H 5 or CH 2 OH.

[0189] Preferred neopentyl polyols are those selected from pentaerythritol, dipentaerythritol, tripentaerythritol, tetraerythritol, trimethylolpropane, trimethylolethane, and neopentyl glycol. In particular, the neopentyl polyol is dipentaerythritol.

[0190] Preferably, a single neopentyl polyol is used to produce the lubricant. In some cases, two or more neopentyl polyols are used. This is particularly the case when a commercial pentaerythritol product includes small amounts of dipentaerythritol, tripentaerythritol, and tetraerythritol.

[0191] In some embodiments, the aforementioned monocarboxylic acid comprises from 5 to 11 carbon atoms, preferably from 6 to 10 carbon atoms.

[0192] Monocarboxylic acids have in particular the following general formula (VII): (VII) R'C(O)OH in which R' is a linear or branched C1-C12 alkyl radical, a C6-C12 aryl radical, a C6-C30 aralkyl radical. Preferably, R' is a C4-C10 alkyl radical, and preferably a C5-C9 alkyl radical.

[0193] In particular, the monocarboxylic acid may be selected from the group consisting of butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, n-octanoic acid, n-nonanoic acid, n-decanoic acid, 3-methylbutanoic acid, 2-methylbutanoic acid, 2,4-dimethylpentanoic acid, 2-ethylhexanoic acid, 3,3,5-trimethylhexanoic acid, benzoic acid, and mixtures thereof.

[0194] In some embodiments, the monocarboxylic acid is n-heptanoic acid, or a mixture of n-heptanoic acid with another linear monocarboxylic acid, particularly n-octanoic acid and / or n-decanoic acid.

[0195] Such a mixture of monocarboxylic acid may in particular comprise between 15 and 100 mol% of heptanoic acid and between 0 and 85 mol% of other monocarboxylic acid(s). In particular, the mixture may comprise between 75 and 100 mol% of heptanoic acid, and between 0 and 25 mol% of a mixture of octanoic acid and decanoic acid in a molar ratio of 3:2.

[0196] In some embodiments, the POEs include: i) from 45 to 55% by mass of a monopentaerythritol ester with at least one monocarboxylic acid having from 2 to 15 carbon atoms; ii) less than 13% by mass of a dipentaerythritol ester with at least one monocarboxylic acid having from 2 to 15 carbon atoms; iii) less than 10% by mass of a tripentaerythritol ester with at least one monocarboxylic acid having from 2 to 15 carbon atoms; and iv) at least 25% by mass of an ester of tetraerythritol and other pentaerythritol oligomers, with at least one monocarboxylic acid having from 2 to 15 carbon atoms

[0197] In some embodiments, the POEs comprise, by mass, from 0 to 5%, or from 5 to 10%, or from 10 to 15%, or from 15 to 20%, or from 20 to 25%, or from 25 to 30%, or from 30 to 35%, or from 35 to 40%, or from 40 to 45%, or from 45 to 50%, or from 50 to 55%, or from 55 to 60%, or from 60 to 65%, or from 65 to 70%, or from 70 to 75%, or from 75 to 80%, or from 80 to 85%, or from 85 to 90%, or from 90 to 95%, or from 95 to 100%, of a monopentaerythritol ester with at least one monocarboxylic acid containing from 2 to 15 atoms of carbon.

[0198] Type D POEs correspond to the following formula (VIII): in which: R 7< , R 8< , R 9< , R 10< , R 11< and R 12< are, independently of each other, H or CH 3 ; a, b, c, y, x and z, are, independently of each other, an integer; a+x, b+y, and c+z are, independently of each other, integers ranging from 1 to 20; R 13< , R 14< and R 15< are, independently of each other, selected from the group consisting of aliphatic or branched alkyls, alkenyls, cycloalkyls, aryls, alkylaryls, arylalkyls, alkylcycloalkyls, cycloalkylalkyls, arylcycloalkyls, cycloalkylaryls, alkylcycloalkylaryls, alkylarylcycloalkyls, arylcycloalkylalkyls, arylalkylcycloalkyls, cycloalkylalkylaryls and cycloalkylarylalkyls, R 13< , R 14< and R 15< having from 1 to 17 carbon atoms, and may be optionally substituted.

[0199] In some embodiments, each of R 13< , R 14< and R 15< independently of each other represents a linear or branched alkyl group, an alkenyl group, a cycloalkyl group, said alkyl, alkenyl or cycloalkyl groups possibly comprising at least one heteroatom selected from N, O, Si, F or S. Preferably, each of R 13< , R 14< and R 15< independently of each other has from 3 to 8 carbon atoms, preferably from 5 to 7 carbon atoms.

[0200] Preferably, a+x, b+y, and c+z are, independently of each other, integers ranging from 1 to 10, preferably from 2 to 8, and even more preferably from 2 to 4.

[0201] Preferably, R 7< , R 8< , R 9< , R 10< , R 11< and R 12< represent H.

[0202] The POEs of formula (VIII) above can typically be prepared as described in paragraphs

[0027] to

[0030] of international application WO 2012 / 177742.

[0203] In particular, POEs of formula (VIII) can be obtained by esterification of glycerol alkoxylates (as described in paragraph

[0027] of WO 2012 / 177742) with one or more monocarboxylic acids having from 2 to 18 carbon atoms.

[0204] In some embodiments, the monocarboxylic acids have one of the following formulas: R 13< COOH, R 14< COOH and R 15< COOH, wherein R 13< , R 14< and R 15< are as defined above. Derivatives of the carboxylic acids may also be used, such as anhydrides, esters and acyl halides.

[0205] Esterification can be carried out with one or more monocarboxylic acids. Preferred monocarboxylic acids are those selected from the group consisting of acetic acid, propanoic acid, butyric acid, isobutanoic acid, pivalic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, 3,3,5-trimethylhexanoic acid, nonanoic acid, decanoic acid, neodecanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, palmitoleic acid, citronellic acid, undecenoic acid, lauric acid, undecylenic acid, linolenic acid, arachidic acid, behenic acid, tetrahydrobenzoic acid, hydrogenated or non-hydrogenated abietic acid, 2-ethylhexanoic acid, furoic acid, benzoic acid,4-acetylbenzoic acid, pyruvic acid, 4-tert-butylbenzoic acid, naphthenic acid, 2-methylbenzoic acid, salicylic acid, their isomers, their methyl esters, and their mixtures.,

[0206] In some embodiments, the esterification is carried out with one or more monocarboxylic acids selected from the group consisting of pentanoic acid, 2-methylbutanoic acid, n-hexanoic acid, n-heptanoic acid, 3,3,5-trimethylhexanoic acid, 2-ethylhexanoic acid, n-octanoic acid, n-nonanoic acid and isononanoic acid.

[0207] Preferably, the esterification is carried out with one or more monocarboxylic acids selected from the group consisting of butyric acid, isobutyric acid, n-pentanoic acid, 2-methylbutanoic acid, 3-methylbutanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid, 3,3,5-trimethylhexanoic acid, n-nonanoic acid, decanoic acid, undecanoic acid, undecelenic acid, lauric acid, stearic acid, isostearic acid, and mixtures thereof.

[0208] In some embodiments, the POEs have the following formula (IX): in which: each of R 17< and R 18< , is, independently of each other, H or CH 3 ; each of m and n, is, independently of each other, an integer, with m+n being an integer ranging from 1 to 10; R 16< and R 19< are, independently of each other, selected from the group consisting of aliphatic or branched alkyls, alkenyls, cycloalkyls, aryls, alkylaryls, arylalkyls, alkylcycloalkyls, cycloalkylalkyls, arylcycloalkyls, cycloalkylaryls, alkylcycloalkylaryls, alkylarylcycloalkyls, arylcycloalkylalkyls, arylalkylcycloalkyls, cycloalkylalkylaryls and cycloalkylarylalkyls, R 16< and R 19< having from 1 to 17 carbon atoms, and may be optionally substituted.

[0209] In some embodiments, each of R 16< and R 19< independently of each other represents a linear or branched alkyl group, an alkenyl group, a cycloalkyl group, said alkyl, alkenyl or cycloalkyl groups being able to comprise at least one heteroatom selected from N, O, Si, F or S. Preferably, each of R 16< and R 19< independently of each other has from 3 to 8 carbon atoms, preferably from 5 to 7 carbon atoms.

[0210] In some embodiments, each of R 17< and R 18< represents H, and / or m+n is an integer ranging from 2 to 8, from 4 to 10, from 2 to 5, or from 3 to 5. In particular, m+n is 2, 3, or 4.

[0211] In some embodiments, the POEs of formula (IX) above are triethylene glycol diesters, tetraethylene glycol diesters, particularly with one or two monocarboxylic acids having from 4 to 9 carbon atoms.

[0212] The POEs of formula (IX) above may be prepared by esterification of an ethylene glycol, a propylene glycol, or an oligo- or polyalkylene glycol, (which may be an oligo- or polyethylene glycol, oligo- or polypropylene glycol, or an ethylene glycol-propylene glycol block copolymer), with one or two monocarboxylic acids having from 2 to 18 carbon atoms. The esterification may be carried out in a manner identical to the esterification reaction used to prepare the POEs of formula (VIII) above.

[0213] In particular, monocarboxylic acids identical to those used to prepare the POEs of formula (VIII) above, can be used to form the POEs of formula (IX).

[0214] In certain embodiments, the lubricant comprises from 20 to 80%, preferably from 30 to 70%, and preferentially from 40 to 60% by mass of at least one POE of formula (VIII), and from 80 to 20%, preferably from 70 to 30%, and preferentially from 60 to 40% by mass of at least one POE of formula (IX).

[0215] Generally, some alcohol functions may not be esterified during the esterification reaction, however their proportion remains low. Thus, POEs can comprise between 0 and 5% relative molar of CH 2 OH units compared to -CH 2 -OC(=O)- units.

[0216] The lubricant used in the process of the invention is such that the solubility of HFO-1234yf in this lubricant is lower than the solubility of HFC-134a in the lubricant

[0217] By " solubility »of a compound A in the lubricant means the maximum mass proportion of compound A in the gaseous state which can be absorbed by the lubricant in the liquid phase (i.e. the maximum relative mass proportion of compound A in the lubricant in the liquid phase, when the lubricant is brought into contact with compound A in the gaseous state). The solubility can be measured as described below in Example 1.

[0218] The above solubility condition is verified at a temperature of 0°C, and at a pressure which is: 2.2 bar abs for HFO-1234yf; and 2.0 bar abs for HFC-134a.

[0219] These pressure values ​​correspond to the vapor saturation pressure of HFO-1234yf and HFC-134a respectively at a temperature of -10°C.

[0220] When a replacement is made, the replacement lubricant may be the same or different from the original lubricant.

[0221] The initial lubricant can be of any type. It can be chosen in particular from mineral oils, silicone oils, natural or synthetic paraffins, naphthenes, alkylbenzenes, poly-alpha olefins, polyalkene glycols (PAG), polyol esters (POE), polyvinyl ethers and mixtures thereof.

[0222] Preferably, the initial lubricant comprises a POE or is a POE.

[0223] The detailed description of possible POE types given above also applies to the initial lubricant, when it includes a POE or is a POE. Additives

[0224] The additives which may be present in the heat transfer composition of the invention may in particular be chosen from nanoparticles, stabilizers, surfactants, tracer agents, fluorescent agents, odorous agents and solubilizing agents.

[0225] Preferably, the additives are not lubricants.

[0226] The stabilizer(s), when present, preferably represent at most 5% by mass in the heat transfer composition. Among the stabilizers, mention may be made in particular of nitromethane, ascorbic acid, terephthalic acid, azoles such as tolutriazole or benzotriazole, phenolic compounds such as tocopherol, hydroquinone, t-butyl hydroquinone, 2,6-di-tert-butyl-4-methylphenol, epoxides (optionally fluorinated or perfluorinated alkyl or alkenyl or aromatic) such as n-butyl glycidyl ether, hexanediol diglycidyl ether, allyl glycidyl ether, butylphenyl glycidyl ether, phosphites, phosphonates, thiols and lactones.

[0227] As nanoparticles, we can use in particular carbon nanoparticles, metal oxides (copper, aluminum), TiO 2 , Al 2 O 3 , MoS 2 ...

[0228] Tracer agents (which can be detected) include deuterated or non-deuterated hydrofluorocarbons, deuterated hydrocarbons, perfluorocarbons, fluoroethers, brominated compounds, iodinated compounds, alcohols, aldehydes, ketones, nitrous oxide and combinations thereof. The tracer agent is different from the compounds constituting the refrigerant.

[0229] Examples of solubilizing agents include hydrocarbons, dimethyl ether, polyoxyalkylene ethers, amides, ketones, nitriles, chlorocarbons, esters, lactones, aryl ethers, fluoroethers, and 1,1,1-trifluoroalkanes. The solubilizing agent is different from the heat transfer compound(s) comprising the refrigerant.

[0230] Examples of fluorescent agents include naphthalimides, perylenes, coumarins, anthracenes, phenanthracenes, xanthenes, thioxanthenes, naphthoxanthenes, fluoresceins and derivatives and combinations thereof.

[0231] Examples of odorants include alkylacrylates, allylacrylates, acrylic acids, acryl esters, alkyl ethers, alkyl esters, alkynes, aldehydes, thiols, thioethers, disulfides, allylisothiocyanates, alkanoic acids, amines, norbornenes, norbornene derivatives, cyclohexene, heterocyclic aromatic compounds, ascaridole, o-methoxy(methyl)phenol and combinations thereof.

[0232] When a replacement is made, the additives described above may be present in the initial heat transfer composition and / or in the replacement heat transfer composition. Preferably, the same additives are present in the initial heat transfer composition and in the replacement heat transfer composition. Formulation of heat transfer compositions

[0233] In each heat transfer composition described herein (where applicable, initial heat transfer composition on the one hand, and replacement heat transfer composition on the other hand), the mass proportion of refrigerant fluid may represent in particular from 1 to 5% of the composition; or from 5 to 10% of the composition; or from 10 to 15% of the composition; or from 15 to 20% of the composition; or from 20 to 25% of the composition; or from 25 to 30% of the composition; or from 30 to 35% of the composition; or from 35 to 40% of the composition; or from 40 to 45% of the composition; or from 45 to 50% of the composition; or from 50 to 55% of the composition; or from 55 to 60% of the composition; or from 60 to 65% of the composition; or from 65 to 70% of the composition; or 70 to 75% of the composition; or 75 to 80% of the composition; or 80 to 85% of the composition; or 85 to 90% of the composition; or 90 to 95% of the composition; or 95 to 99% of the composition.

[0234] In the present description, when several possible ranges are envisaged, the ranges resulting from the combination of these are also covered: for example, the mass proportion of refrigerant fluid in the heat transfer composition can be from 50 to 55%, and from 55 to 60%, i.e. from 50 to 60%, etc.

[0235] Preferably, the heat transfer composition of the invention (which where appropriate is a replacement heat transfer composition) comprises at least 50% by mass of refrigerant, and in particular from 50% to 95% by mass.

[0236] Where appropriate, the initial heat transfer composition preferably comprises at least 50% by mass of refrigerant, and in particular from 50% to 95% by mass.

[0237] In each heat transfer composition described herein (where applicable, initial heat transfer composition on the one hand, and replacement heat transfer composition on the other hand), the mass proportion of lubricant may represent in particular from 1 to 5% of the composition; or from 5 to 10% of the composition; or from 10 to 15% of the composition; or from 15 to 20% of the composition; or from 20 to 25% of the composition; or from 25 to 30% of the composition; or from 30 to 35% of the composition; or from 35 to 40% of the composition; or from 40 to 45% of the composition; or from 45 to 50% of the composition; or from 50 to 55% of the composition; or from 55 to 60% of the composition; or from 60 to 65% of the composition; or from 65 to 70% of the composition; or 70 to 75% of the composition; or 75 to 80% of the composition; or 80 to 85% of the composition; or 85 to 90% of the composition; or 90 to 95% of the composition; or 95 to 99% of the composition.

[0238] The additives preferably represent from 0 to 30%, more preferably from 0 to 20%, more preferably from 0 to 10%, more preferably from 0 to 5%, and more preferably from 0 to 2% of each heat transfer composition, in mass proportions. Adaptation of superheat and / or viscosity

[0239] The superheat in the heat transfer method of the invention (optionally implemented with the replacement heat transfer composition, when a replacement is made) may be in particular 1 to 2°C; or 2 to 3°C; or 3 to 4°C; or 4 to 5°C; or 5 to 7°C; or 7 to 10°C; or 10 to 15°C; or 15 to 20°C; or 20 to 25°C; or 25 to 30°C; or 30 to 50°C.

[0240] Superheat ranges of 1 to 20°C, 2 to 10°C and 3 to 5°C are examples of preferred ranges.

[0241] When a replacement is made, the superheat in the same heat transfer process carried out with the initial heat transfer composition may be in particular 1 to 2°C; or 2 to 3°C; or 3 to 4°C; or 4 to 5°C; or 5 to 7°C; or 7 to 10°C; or 10 to 15°C; or 15 to 20°C; or 20 to 25°C; or 25 to 30°C; or 30 to 50°C.

[0242] Superheat ranges of 1 to 20°C, 2 to 10°C and 3 to 5°C are examples of preferred ranges.

[0243] In some embodiments, when a replacement is made, the superheat is set to essentially the same value, by appropriate adjustment of the installation parameters and in particular of the expansion module.

[0244] In other embodiments, when a replacement is made, the overheating is reduced when replacing the heat transfer composition, by an adequate adjustment of the parameters of the installation and in particular of the expansion module.

[0245] Thus, the difference between the superheat when the method is implemented with the initial heat transfer composition and the superheat when the method is implemented, according to the invention, with the replacement heat transfer composition may in particular be: from 1 to 2°C; or from 2 to 3°C; or from 3 to 4°C; or from 4 to 5°C; or from 5 to 6°C; or from 6 to 7°C; or from 7 to 8°C; or from 8 to 9°C; or from 9 to 10°C; or from 10 to 15°C; or more than 15°C.

[0246] The lubricant used in the method of the invention (which, where appropriate, is the replacement lubricant, when a replacement is carried out), preferably has a viscosity of 1 to 1000 centiStokes (cSt or mm 2 < / s).

[0247] All viscosity values ​​refer to kinematic viscosity, measured at a temperature of 40°C, according to the standard DIN EN ISO 3104.

[0248] This lubricant can thus have a viscosity of 1 to 5 cSt, or 5 to 10 cSt, or 10 to 20 cSt, or 20 to 30 cSt, or 30 to 40 cSt, or 40 to 50 cSt, or 50 to 60 cSt, or 60 to 70 cSt, or 70 to 80 cSt, or 80 to 90 cSt, or 90 to 100 cSt, or 100 to 150 cSt, or 150 to 200 cSt, or 200 to 250 cSt, or 250 to 300 cSt, or 300 to 400 cSt, or 400 to 500 cSt, or 500 to 600 cSt, or 600 to 700 cSt, or 700 to 800 cSt, or 800 to 900 cSt, or 900 to 1000 cSt.

[0249] Examples of preferred ranges are 10 to 200 cSt, or 20 to 100 cSt, or 30 to 80 cSt.

[0250] When a replacement is made, the initial lubricant may also have a viscosity of 1 to 5 cSt, or 5 to 10 cSt, or 10 to 20 cSt, or 20 to 30 cSt, or 30 to 40 cSt, or 40 to 50 cSt, or 50 to 60 cSt, or 60 to 70 cSt, or 70 to 80 cSt, or 80 to 90 cSt, or 90 to 100 cSt, or 100 to 150 cSt, or 150 to 200 cSt, or 200 to 250 cSt, or 250 to 300 cSt, or 300 to 400 cSt, or 400 to 500 cSt, or 500 to 600 cSt, or from 600 to 700 cSt, or from 700 to 800 cSt, or from 800 to 900 cSt, or from 900 to 1000 cSt.

[0251] Examples of preferred ranges are 10 to 200 cSt, or 20 to 100 cSt, or 30 to 80 cSt.

[0252] The viscosity of the lubricant is advantageously adapted according to the type of heat transfer process implemented and according to the compressor used.

[0253] In some embodiments, the heat transfer process is a refrigeration process, performed in a refrigerator; in such a case the viscosity of the lubricant is preferably 2 to 60 cSt, more preferably 5 to 50 cSt, and most preferably 10 to 40 cSt. When a replacement is made, these ranges apply to the initial lubricant and / or the replacement lubricant. When a replacement is made, preferably HFC-134a is used as the initial refrigerant.

[0254] In some embodiments, the heat transfer method is carried out with a hermetic or semi-hermetic compressor; in such a case the viscosity of the lubricant is preferably 5 to 100 cSt, more preferably 10 to 80 cSt, and most preferably 20 to 70 cSt. When a replacement is made, these ranges apply to the initial lubricant and / or the replacement lubricant. When a replacement is made, preferably HFC-134a is used as the initial refrigerant.

[0255] In some embodiments, the heat transfer method is carried out with an open compressor; in such a case the viscosity of the lubricant is preferably 10 to 200 cSt, more preferably 20 to 150 cSt, and most preferably 30 to 100 cSt. When a replacement is made, these ranges apply to the initial lubricant and / or the replacement lubricant. When a replacement is made, preferably HFC-134a is used as the initial refrigerant.

[0256] In some embodiments, the heat transfer process is an air conditioning or refrigeration process for industrial or commercial premises, and the compressor used is a scroll compressor; in such a case the viscosity of the lubricant is preferably from 5 to 250 cSt, more preferably from 10 to 200 cSt, and more preferably from 20 to 150 cSt. When a replacement is made, these ranges apply to the initial lubricant and / or the replacement lubricant. When a replacement is made, preferably HFC-134a is used as the initial refrigerant.

[0257] In some embodiments of the invention, when a replacement is made, the replacement lubricant is different from the initial lubricant, and the viscosity of the replacement lubricant is lower than that of the initial lubricant. It is preferred that both the initial lubricant and the replacement lubricant are POE lubricants as described above.

[0258] The viscosity of the replacement lubricant (in cSt) may thus be lower by 1 to 2%; or by 2 to 3%; or by 3 to 4%, or by 4 to 5%; or by 5 to 10%; or by 10 to 15%; or by 15 to 20%; or by 20 to 25%; or by 25 to 30%; or by 30 to 40%; or by 40 to 50%; or by more than 50%; compared to the viscosity of the initial lubricant (in cSt).

[0259] The difference between the viscosity of the replacement lubricant and the viscosity of the original lubricant may be, for example, 1 to 2 cSt; or 2 to 3 cSt; or 3 to 4 cSt; or 4 to 5 cSt; or 5 to 10 cSt; or 10 to 15 cSt; or 15 to 20 cSt; or 20 to 25 cSt; or 25 to 30 cSt; or 30 to 40 cSt; or 40 to 50 cSt; or 50 to 60 cSt; or 60 to 70 cSt; or 70 to 80 cSt; or 80 to 90 cSt; or 90 to 100 cSt; or 100 to 150 cSt; or 150 to 200 cSt; or 200 to 250 cSt; or 250 to 300 cSt; or more than 300 cSt. EXAMPLES

[0260] The following examples illustrate the invention without limiting it.

[0261] In these examples, we consider a refrigeration plant operating either with HFC-134a, or with HFO-1234yf, or with HFO-1234ze (in trans form). The lubricant used is an ISO 55 POE oil with a viscosity of 55 cSt at 40°C. Example 1 - measurement of solubility, viscosity and density.

[0262] Solubility measurements are carried out according to the following protocol.

[0263] The solubility measuring device consists of a metal cell with a viewport equipped with a camera to view the interior of the cell. The cell is also equipped with absolute pressure sensors, high-precision differential pressure, temperature and dynamic viscosity measurement. The viscosity measuring sensor is immersed in the liquid phase of the mixture under test.

[0264] All sensors are calibrated before testing to measure pressure, temperature, viscosity, and liquid volume in the cell. The density of the liquid phase is calculated from these measurements.

[0265] The entire cell is kept at a constant temperature thanks to a double jacket system supplied by a heat transfer fluid with adjustable temperature.

[0266] A specific amount of oil is introduced into the cell. The first tests consist of measuring the viscosity of the oil at different temperatures. Specific amounts of gas are then gradually introduced. After each addition of gas, measurements are taken over a specific temperature range.

[0267] The amount of gas in the vapor phase in the cell headspace is calculated using liquid level measurements and prior knowledge of the behavior of pure gas as a function of temperature and pressure.

[0268] The maximum amount of gas dissolved in the liquid is calculated based on the mass of the charged gas and the mass of the gaseous atmosphere. Example 2 - Determination of solubility in a vapor compression system at the compressor inlet

[0269] Consider a vapor compression system operating with HFC-134a, HFO-1234yf, or HFO-1234ze. The compressor inlet pressures for each fluid are 1.47 bar (HFO-1234ze), 2.0 bar (HFC-134a), and 2.2 bar (HFO-1234yf), respectively. They correspond to the vapor saturation pressure of each fluid at -10°C (neglecting pressure drops). If we now consider a superheat of 10°C or 5°C in the system, the compressor inlet temperature is 0°C or -5°C, respectively.

[0270] The solubility of the oil / refrigerant mixture at the compressor inlet is therefore a function of the operating pressure for each refrigerant and the temperature at the compressor inlet.

[0271] It has been represented on the Figures 1 and 2 Pressure versus temperature curves, at constant solubility, for HFO-1234yf, HFO-1234ze and HFC-134a.

[0272] These curves were obtained by modeling from the measurement results of Example 1, using the following methodology: viscosity, pressure, and density are expressed as equations, as a function of temperature and solubility. Each equation has a number of constants to be determined by regression based on the results of the measurements above. The viscosity equation is a modified form of the Walther equation, with nine constants. The pressure equation also has nine constants. These two equations are described in the document Solubility, viscosity, and density of refrigerant / lubricant mixtures by David R. Henderson (Spauschus Associates, Inc. 300 Corporate Center Court Eagle's Landing Stockbridge, GA 30281, April 1994) on page 3.The density equation is a linear equation as a function of solubility (x) and temperature (t) with four constants to be regressed according to the measurement results (density = a + bt + cx + dxt with a, b, c, d constant). Thus, to determine one of the parameters (temperature or pressure, density or viscosity or solubility), it is sufficient to solve a system of equations with several unknowns.

[0273] The oil and refrigerant blends shown contain 22% HFC-134a (curve A), 15% HFO-1234yf (curve B), 23.8% HFO-1234ze (curve C), with a 10°C superheat in the system; or 26% HFC-134a (curve D), 18.5% HFO-1234yf (curve E), and 27.6% HFO-1234ze (curve F) with a 5°C superheat in the system.

[0274] Thus, if HFC-134a is replaced by HFO 1234yf, the solubility of the refrigerant is reduced, even if the superheat is reduced from 10°C to 5°C. This is not the case with HFO 1234ze. Example 3 - Determination of viscosity in a vapor compression system at the compressor inlet

[0275] With the measuring device described in Example 1, dynamic viscosity measurements of different mixtures were carried out. The kinematic viscosity is calculated from the dynamic viscosity and density measurements.

[0276] If we consider the same system from Example 2, the kinematic viscosity of the refrigerant / oil mixture at a temperature of 0°C and at the corresponding operating pressures (corresponding to an evaporation temperature of -10°C and 10°C superheat) is 44 cSt with HFC-134a and 79 cSt with HFO-1234yf. It is 45.18 cSt with HFO-1234ze

[0277] The kinematic viscosity of the refrigerant / oil mixture at a temperature of -5°C and at the corresponding operating pressures (corresponding to an evaporation temperature of -10°C and 5°C superheat) is 38.6 cSt with HFC-134a and 69 cSt with HFO-1234yf. It is 40.3 cSt with HFO-1234ze.

[0278] Thus, even with reduced superheat, the oil / HFO-1234yf blend maintains a high viscosity compared to the reference with HFC-134a.

[0279] On the figure 3 , The kinematic viscosity is plotted as a function of temperature at constant pressure for each refrigerant fluid under the pressure conditions of Example 2. The curve marked with a star (*) corresponds to the oil alone. These curves are the results of the modeling of the measurement points discussed above.

[0280] It is observed that HFO-1234yf exhibits a viscosity behavior that is clearly distinct from that of HFC-134a and HFO-1234ze when the mixture temperature is below 40°C.

[0281] The table below summarizes the results obtained: Refrigerant HFC-134a HFC-134a HFO-1234yf HFO-1234yf HFO-1234ze HFO-1234ze Saturation pressure (bar) 2 2 2,2 2,2 1,47 1,47 Compressor inlet temperature 0°C -5°C 0°C -5°C 0°C -5°C Overheated 10°C 5°C 10°C 5°C 10°C 5°C Minimum oil temperature 0°C -5°C 0°C -5°C 0°C -5°C Solubility 22 % 26 % 15% 18,5 % 23,8 % 27,6 % Viscosity (mm 2 < / s) 44 38,6 79 69 45,2 40,3 Example 4 - performance

[0282] A performance analysis of a plant operating with a condensing temperature of 40°C, an evaporating temperature of -10°C in evaporation, 7°C of subcooling and a variable superheat of 3°C to 10°C was carried out as follows. The thermodynamic properties were calculated using Refprop software.

[0283] The results are presented in the table below: P max (bar) P min (bar) P max / P min ratio Overheating (°C) RI % CAP % COP HFC-134a 10,2 2,0 5,07 10,0 77 100 100 H FO-1234ze 7,7 1,5 5,20 10,0 77 73 99 HFO-1234yf 10,2 2,2 4,59 10,0 79 95 97 HFO-1234yf 10,2 2,2 4,59 9,0 79 96 98 HFO-1234yf 10,2 2,2 4,59 8,0 79 96 98 HFO-1234yf 10,2 2,2 4,59 7,0 79 97 99 HFO-1234yf 10,2 2,2 4,59 6,0 79 97 99 HFO-1234yf 10,2 2,2 4,59 5,0 79 98 100 HFO-1234yf 10,2 2,2 4,59 4,0 79 98 100 HFO-1234yf 10,2 2,2 4,59 3,0 79 99 101

[0284] In this table, P max and P min denote the maximum and minimum pressures in the system, Surch. denotes superheat, RI denotes isentropic efficiency, CAP denotes volumetric capacity, COP denotes coefficient of performance.

[0285] These results demonstrate that the coefficient of performance (COP) and volumetric capacity increase with decreasing superheat. Thus, going from 10°C to 5°C superheat increases the COP by 3% and the capacity by 2%.

[0286] According to the invention, the reduction of superheat at the compressor inlet is possible thanks to the low solubility of HFO-1234yf with POE oils compared to HFC-134a and HFO-1234ze.

Claims

1. Process for air conditioning or refrigeration for industrial or commercial premises by means of a heat transfer installation using a scroll compressor and containing a heat transfer composition, the heat transfer composition comprising: - a refrigerant fluid which comprises 2,3,3,3-tetrafluoropropene, and - a lubricant; in which the lubricant comprises a polyol ester, the solubility of the 2, 3, 3, 3-tetrafluoropropene in the lubricant at 0°C and at an absolute pressure of 2.2 bar being less than the solubility of 1,1,1,2-tetrafluoroethane in the lubricant at 0°C and at an absolute pressure of 2.0 bar; the process comprising the successive steps: - of evaporating a refrigerant fluid; - of superheating the refrigerant fluid from 1 to 10°C; - of compressing the refrigerant fluid.

2. Process according to Claim 1, in which the superheating of the refrigerant fluid is from 2 to 10°C, more preferably from 3 to 5°C.

3. Process according to either of Claims 1 and 2, in which the lubricant comprises a dipentaerythritol ester.

4. Process according to one of Claims 1 to 3, in which the lubricant has a kinematic viscosity at 40°C of 10 to 200 cSt, preferably of 20 to 100 cSt and more preferably of 30 to 80 cSt.

5. Process according to one of Claims 1 to 4, in which the refrigerant fluid is evaporated at an average temperature of less than or equal to 10°C, preferably less than or equal to 0°C, more preferably less than or equal to -10°C.

6. Process according to one of Claims 1 to 5, in which the heat transfer installation is an installation intended to operate with an initial heat transfer composition comprising: - an initial refrigerant fluid, and - an initial lubricant, the initial heat transfer composition being different from the heat transfer composition used in the process.

7. Process according to one of Claims 1 to 5, in which said heat transfer composition is a replacement heat transfer composition, which is used as replacement for an initial heat transfer composition comprising: - an initial refrigerant fluid, and - an initial lubricant.

8. Process according to Claim 7, in which the superheating with the replacement heat transfer composition is less than or equal to the superheating when the same process is implemented with the initial heat transfer composition; and preferably the superheating with the replacement heat transfer composition is less by at least 2°C, preferably by at least 5°C, more preferably by at least 10°C, relative to the superheating when the same process is implemented with the initial heat transfer composition.

9. Process according to Claim 7 or 8, in which the lubricant of the replacement heat transfer composition is identical to the initial lubricant.

10. Process according to Claim 7 or 8, in which the lubricant of the replacement heat transfer composition is different from the initial lubricant.

11. Process according to Claim 10, in which the lubricant of the replacement heat transfer composition has a kinematic viscosity at 40°C which is less than or equal to the kinematic viscosity at 40°C of the initial lubricant, the difference between the kinematic viscosity at 40°C of the initial lubricant and the kinematic viscosity at 40°C of the lubricant of the replacement heat transfer composition being preferably greater than or equal to 5 cSt, more preferably greater than or equal to 10 cSt.

12. Process according to one of Claims 7 to 11, in which the initial lubricant comprises a polyol ester, and preferably comprises a dipentaerythritol ester.

13. Process according to one of Claims 6 to 12, in which the initial refrigerant fluid comprises 1,1,1,2-tetrafluoroethane or consists essentially of 1,1,1,2-tetrafluoroethane.