EP2705106A1

EP2705106A1 - Heat-transfer compositions exhibiting improved miscibility with the lubricating oil

Info

Publication number: EP2705106A1
Application number: EP12717400.1A
Authority: EP
Inventors: Sophie GUERIN; Laurent Abbas; Wissam Rached
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2011-05-04
Filing date: 2012-03-28
Publication date: 2014-03-12
Also published as: CN103502381A; JP2014517859A; FR2974812B1; US9676984B2; US20140075969A1; FR2974812A1; US20160194541A1; CN103502381B; US9315708B2; WO2012150391A1; BR112013028001A2; AU2012251566A1; RU2013153587A; JP2017222843A; RU2577435C2

Abstract

The invention relates to the use of 1,1,1,2-tetrafluoroethane for increasing the miscibility of 2,3,3,3-tetrafluoropropene with a lubricating oil, and in particular with a polyalkylene glycol oil. In this regard, the invention provides heat-transfer compositions and also equipment and processes using these compositions.

Description

HEAT TRANSFER COMPOSITIONS HAVING IMPROVED MISCIBILITY WITH LUBRICATING OIL

MAINE OF THE INVENTION

The present invention relates to 2,3,3,3-tetrafluoropropene heat transfer compositions having improved miscibility with the lubricating island. TECHNICAL PLAN

Fluorocarbon-based fluids are widely used is steam compression heat transfer systems, stopping air conditioning, heat pump, freezing refrigeration devices. These devices have in common to rely on a modynamic cycle including the vaporization of the fluid at low pressure (in which the fluid absorbs heat); compressing the vaporized fluid) at high pressure; condensing the vaporized fluid into a high-ssion liquid (in which the fluid releases heat); and the relaxation of the ie to end the cycle.

The choice of a heat transfer fluid (which may be a pure compound mixture of compounds) is dictated firstly by the -modynamic properties of the fluid, and secondly by elementary stresses. Thus, a particularly important criterion is the pact of the fluid considered on the environment. In particular, the compounds res (chlorofluorocarbons and hydrochlorofluorocarbons) have the advantage of damaging the ozone layer. Thus, they are generally preferred to use non-chlorinated compounds such as rofluorocarbons, fluoroethers and fluoroolefins.

Another environmental constraint is that of climate change potential (GWP). It is therefore essential to develop heat transfer devices with low GWP and good energy performance.

Furthermore, to lubricate the moving parts of the compressor (or npresseurs) of a vapor compression system, an oil ^'ification must be added to the heat transfer fluid. The oil can be generally mineral or synthetic. The choice of the lubricating oil is made according to the type of compressor, and so as not to react with the heat transfer fluid itself and with the other compounds present in the system.

For some heat transfer systems (especially small ones), the lubricating oil is generally allowed to circulate throughout the circuit, the piping being designed so that the oil can flow by gravity to the compressor. In other heat transfer systems (especially large ones), an oil separator is provided immediately after the compressor as well as an oil level control device, ensuring a return of the oil to the or the compressors. Even when an oil separator is present, the system piping must still be designed so that the oil can return by gravity to the oil separator or the compressor.

The document WO 2004/037913 describes compositions based on fluoroolefins and especially based on tetrafluoropropene or pentafluoropropene. In Example 2 is reported the miscibility of 1,2,3,3,3-pentafluoropropene (HFO-1225ye) with various lubricating oils, as well as that of 1, 3,3,3-tetrafluoropropene (HFO-1234ze) with various lubricating oils. In Example 3 is reported the compatibility of HFO-1234ze and 3,3,3-trifluoropropene (HFO-1243zf) with lubricating oils of the polyalkylene glycol type.

WO 2005/042663 is specifically concerned with the miscibility of mixtures of fluorolefins and lubricating oils. The examples provided for these mixtures are essentially the same as those of WO 2004/037913.

WO 2006/094303 describes a large number of heat transfer compositions comprising fluoroolefins and additional compounds. Among the numerous compositions cited are mixtures based on 2,3,3,3-tetrafluoropropene (HFO-1234yf) and 1,1,1,2-tetrafluoroethane (HFC-134a). In addition, the document generally teaches combining the list of many possible refrigerants with a list of lubricating oils.

When the heat transfer compound (s) exhibit poor miscibility with the lubricating oil, the latter tends to be trapped at the evaporator and not to return to the compressor, which does not allow correct operation. of the system. In this respect, there is still a need to develop low GWP (and good energy performance) heat transfer compositions in which the heat transfer compounds exhibit good miscibility with the lubricating oil.

In particular, HFO-1234yf is a heat transfer compound of particular interest because of its low GWP and its good energy performance. On the other hand, its miscibility with certain lubricating oils is imperfect and limits its application. It is therefore desirable to improve the miscibility of compositions based on HFO-1234yf with the usual lubricating oils.

SUMMARY OF THE INVENTION

The invention firstly relates to a composition comprising 2,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane and polyalkylene glycol.

According to one embodiment, 2,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane and polyalkylene glycol represent at least 95%, preferably at least 99%, more preferably less 99.9% of the composition.

According to one embodiment, the composition comprises from 1 to 99% polyalkylene glycol, preferably from 5 to 50%, more preferably from 10 to 40%, and most preferably from 15 to 35%.

According to one embodiment, the mass ratio between 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane is from 1: 99 to 99: 1, preferably from 25:75 to 95: 5, more preferably from 50:50 to 92: 8, and most preferably from 55:45 to 92: 8.

According to one embodiment, the polyalkylene glycol has a viscosity of 1 to 1000 centistokes at 40 ° C, preferably 10 to 200 centistokes at 40 ° C, more preferably 20 to 100 centistokes at 40 ° C and ideally from 40 to 50 centistokes at 40 ° C.

According to one embodiment, the composition further comprises: one or more additives chosen from heat transfer compounds, lubricants, stabilizers, surfactants, tracer agents, fluorescent agents, odorants, solubilizing agents and their mixtures; preferably one or more additives selected from stabilizers, surfactants, tracer agents, fluorescers, odorants, solubilizers and mixtures thereof. The invention also relates to the use of polyalkylene glycol as a lubricating oil in a vapor compression circuit, in combination with a heat transfer fluid comprising, preferably, a mixture of 2,3,3 , 3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane.

According to one embodiment, the polyalkylene glycol is used in a proportion of 1 to 99%, preferably 5 to 50%, more preferably 10 to 40%, and ideally 15 to 35%, relative to sum of the polyalkylene glycol and the heat transfer fluid.

According to one embodiment, the mass ratio between 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane in the heat transfer fluid is from 1: 99 to 99: 1, preferably from 25:75 to 95: 5, more preferably from 50:50 to 92:8, and most preferably from 55:45 to 92:8.

According to one embodiment, the mass ratio between 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane in the heat transfer fluid is from 60:40 to 99.9: 0, 1, preferably 68:32 to 99.9: 0.1, and more preferably 68:32 to 95: 5.

The invention also relates to a heat transfer installation comprising a vapor compression circuit containing a heat transfer composition which is a composition as described above.

According to one embodiment, the plant is chosen from mobile or stationary heat pump heating, air conditioning, refrigeration, freezing and Rankine cycles, and in particular from automotive air-conditioning installations.

The invention also relates to a method for heating or cooling a fluid or a body by means of a vapor compression circuit containing a heat transfer fluid, said method comprising successively at least partial evaporation of the heat transfer fluid, the compression of the heat transfer fluid, the at least partial condensation of the heat transfer fluid and the expansion of the heat transfer fluid, wherein the heat transfer fluid is associated with a heat transfer fluid. lubrication to form a heat transfer composition, said heat transfer composition being a composition as described above.

The invention also relates to a method for reducing the environmental impact of a heat transfer installation comprising a vapor compression circuit containing an initial heat transfer fluid, said method comprising a step of replacing the heat transfer fluid. initial heat in the vapor compression circuit by a final heat transfer fluid, the final heat transfer fluid having a GWP lower than the initial heat transfer fluid, wherein the final heat transfer fluid is associated with a lubricating oil for forming a heat transfer composition, said heat transfer composition being a composition as described above.

The invention also relates to the use of 1,1,1,2-tetrafluoroethane to increase the miscibility of 2,3,3,3-tetrafluoropropene with a lubricating oil.

According to one embodiment, the lubricating oil is polyalkylene glycol, and preferably has a viscosity of 1 to 1000 centistokes at 40 ° C, more preferably 10 to 200 centistokes at 40 ° C, more preferably from 20 to 100 centistokes at 40 ° C and ideally from 40 to 50 centistokes at 40 ° C.

According to one embodiment, 1, 1, 1, 2-tetrafluoroethane is used in a proportion of 1 to 99%, preferably 5 to 75%, more particularly preferably 8 to 50%, ideally 8 to 45%. %, based on the sum of 1, 1, 1, 2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene.

The invention also relates to a kit comprising:

a heat transfer fluid comprising 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane on the one hand;

a lubricating oil comprising a polyalkylene glycol on the other hand;

for use in a heat transfer installation comprising a vapor compression circuit.

The present invention makes it possible to meet the needs felt in the state of the art. More particularly, it provides low GWP heat transfer compositions having good energy performance, and wherein the heat transfer compounds exhibit good miscibility with the lubricating oil. In particular, the invention provides HFO-1234yf-based heat transfer compositions having improved miscibility with certain lubricating oils such as polyalkylene glycols.

This is accomplished by mixing HFO-1234yf with HFC-134a. Thus, the present inventors have found that HFC-134a improves the miscibility properties of HFO-1234yf with polyalkylene glycols, beyond what could be expected by a simple extrapolation of the miscibility properties of HFO-1234yf. on the one hand and HFC-134a on the other, with the lubricating oil. There is therefore a synergistic effect between HFO-1234yf and HFC-134a from the point of view of miscibility with the lubricating oil.

The polyalkylene glycol type oils have good lubricity, low pour point, good low temperature fluidity, and good compatibility with elastomers generally present in a vapor compression circuit. They are also relatively less expensive than other lubricating oils and they are oils whose use is currently very widespread in certain fields, and particularly in the field of automotive air conditioning. It is therefore very advantageous to improve the miscibility of HFO-1234yf with a polyalkylene glycol type lubricating oil, so that this heat transfer compound in combination with this lubricating oil can be used to a greater extent.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a graph showing the miscibility of different mixtures of HFO-1234yf and HFC-134a with a polyalkylene glycol ND8 oil. The proportion of HFC-134a with respect to HFO-1234yf and HFC-134a is indicated on the abscissa and varies from 0 to 100%, and the temperature from which the mixture ceases to be miscible with the oil is indicated in FIG. ordinate (in ° C). Experimental data are represented by black circles. The terms NM and M respectively denote the immiscibility zone and the miscibility zone. The results are obtained with an ND8 oil content of 17%, relative to the sum of the three compounds HFO-1234yf / HFC-134a and ND8 oil. See the example below for more details. DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention is now described in more detail and without limitation in the description which follows.

Unless otherwise stated, in the whole of the application the proportions of compounds indicated are given in percentages by mass.

According to the present application, the global warming potential (GWP) is defined with respect to the carbon dioxide and with respect to a duration of 100 years, according to the method indicated in "The scientific assessment of ozone depletion, 2002, a report of the World Meteorological Association's Global Ozone Research and Monitoring Project.

By "heat transfer compound" or "heat transfer fluid" (or refrigerant), is meant a compound, respectively a fluid, capable of absorbing heat by evaporating at low temperature and low pressure and to reject heat by condensing at high temperature and high pressure, in a vapor compression circuit. In general, a heat transfer fluid may comprise one, two, three or more than three heat transfer compounds.

By "heat transfer composition" is meant a composition comprising a heat transfer fluid and optionally one or more additives which are not heat transfer compounds for the intended application.

The invention relies on the use of two heat transfer compounds, namely HFO-1234yf and HFC-134a, and a lubricating oil to form a heat transfer composition.

The heat transfer composition can be introduced as such into a vapor compression circuit. Alternatively, the heat transfer fluid (namely HFO-1234yf and HFC-134a) and the lubricating oil, at the same point or not, can be introduced separately into the circuit. The individual heat transfer compounds (HFO-1234yf and HFC-134a) can also be introduced separately.

The lubricating oil is preferably of the polyalkylene glycol type.

In general, the polyalkylene glycol oil suitable for use within the scope of the invention comprises from 5 to 50 repeating oxyalkylene units, each containing from 1 to 5 carbon atoms.

The polyalkylene glycol may be linear or branched. It can be a homopolymer or a copolymer of 2, 3 or more of 3 groups selected from oxyethylene, oxypropylene, oxybutylene, oxypentylene and combinations thereof.

Preferred polyalkylene glycols comprise at least 50% oxypropylene groups. For the purposes of the invention, the polyalkylene glycol may comprise polyalkylene glycols of different formulas in a mixture.

Suitable polyalkylene glycols are disclosed in US 4,971,712. Other suitable polyalkylene glycols are the polyalkylene glycols having hydroxyl groups at each end, as described in US Pat. No. 4,755,316. Other suitable polyalkylene glycols are the polyalkylene glycols having a capped hydroxyl end. The hydroxyl group may be capped with an alkyl group containing from 1 to 10 carbon atoms (and optionally containing one or more heteroatoms such as nitrogen), or a fluoroalkyl group containing heteroatoms such as nitrogen, or a fluoroalkyl group as described in US 4,975,212, or other similar groups.

When the two hydroxyl ends of the polyalkylene glycol are capped, one can use the same end group or a combination of two distinct groups.

The terminal hydroxyl groups may also be capped to form an ester with a carboxylic acid, as described in US 5,008,028. The carboxylic acid can also be fluorinated.

When both ends of the polyalkylene glycol are capped, one or the other may be an ester, or one end may be capped with an ester and the other end be free or capped with one of the aforementioned alkyl, heteroalkyl or fluoroalkyl groups.

Commercially available polyalkylene glycol lubricating oils are, for example, Goodwrench oils from General Motors and MOPAR-56 from Daimler-Chrysler. Other suitable oils are made by Dow Chemical and Denso.

The viscosity of the lubricating oil may be, for example, from 1 to 1000 centistokes at 40 ° C, preferably from 10 to 200 centistokes at 40 ° C and more preferably from 20 to 100 centistokes at 40 ° C, and ideally 40 to 50 centistokes at 40 ° C.

The viscosity is determined according to ISO viscosity grades, according to ASTM D2422.

The oil marketed by Denso under the name ND8, having a viscosity of 46 centistokes, is particularly suitable. The proportion of lubricating oil to be used in combination with the heat transfer fluid depends mainly on the type of installation concerned. Indeed, the total quantity of lubricating oil in the installation depends mainly on the nature of the compressor, while the total amount of heat transfer fluid in the installation depends mainly on the exchangers and the piping.

In general, the proportion of lubricating oil in the heat transfer composition, or in other words in relation to the sum of the lubricating oil and the heat transfer fluid, is from 1 to 99%, preferably from 5 to 50%, for example 10 to 40% or 15 to 35%.

According to a particular embodiment, the lubricating oil used consists of the polyalkylene glycol described above, with the exception of any other lubricating compound.

According to an alternative embodiment, another lubricating oil is used in combination with the polyalkylene glycol. It may especially be chosen from mineral oils, silicone oils, paraffins of natural origin, naphthenes, synthetic paraffins, alkylbenzenes, poly-alpha olefins, polyol esters and / or polyvinyl ethers. Polyol esters and polyvinyl ethers are preferred. When another lubricating oil is used in combination with the polyalkylene glycol, it is desirable that the miscibility of HFO-1234yf and / or HFC-134a with this oil is greater than the miscibility of HFO-1234yf and / or HFC-134a with polyalkylene glycol. This is particularly the case for at least a portion of the oils of the polyol ester or polyvinyl ether type.

The heat transfer compounds mainly used in the context of the present invention are HFO-1234yf and HFC-134a.

However, the heat transfer compositions according to the invention may optionally comprise one or more additional heat transfer compounds, besides HFO-1234yf and HFC-134a. These additional heat transfer compounds may be chosen especially from hydrocarbons, hydrofluorocarbons, ethers, hydrofluoroethers and fluoroolefins.

According to particular embodiments, the heat transfer fluids according to the invention may be ternary (consisting of three heat transfer compounds) or quaternary (consisting of four heat transfer compounds), in combination with the lubricating oil to form the heat transfer compositions according to the invention.

However, binary heat transfer fluids are preferred.

By binary fluid is meant either a fluid consisting of a mixture of HFO-1234yf and HFC-134a; a fluid consisting essentially of a mixture of HFO-1234yf and HFC-134a, but which may contain impurities in a proportion of less than 1%, preferably less than 0.5%, preferably less than 0.1%, preferably less than 0.05% and preferably less than 0.01%.

According to particular embodiments, the proportion of HFO-1234yf in the heat transfer fluid may be: 0.1 to 5%; or 5 to 10%; or 10 to 15%; or 15 to 20%; or from 20 to 25%; or 25 to 30%; or from 30 to 35%; or 35 to 40%; or 40 to 45%; or 45 to 50%; or 50 to 55%; or 55 to 60%; or from 60 to 65%; or from 65 to 70%; or 70 to 75%; or from 75 to 80%; or from 80 to 85%; or from 85 to 90%; or from 90 to 95%; or 95 to 99.9%.

According to particular embodiments, the proportion of HFC-134a in the heat transfer fluid may be: 0.1 to 5%; or 5 to 10%; or 10 to 15%; or 15 to 20%; or from 20 to 25%; or 25 to 30%; or from 30 to 35%; or 35 to 40%; or 40 to 45%; or 45 to 50%; or 50 to 55%; or 55 to 60%; or from 60 to 65%; or from 65 to 70%; or 70 to 75%; or from 75 to 80%; or from 80 to 85%; or from 85 to 90%; or from 90 to 95%; or 95 to 99.9%.

The values given in the previous three paragraphs apply to the heat transfer fluid without the lubricating oil, and not to the heat transfer composition which comprises the heat transfer fluid, the lubricating oil and optionally other additives.

The other additives that may be used in the context of the invention may especially be chosen from stabilizers, surfactants, tracer agents, fluorescent agents, odorants and solubilizing agents.

The stabilizer (s), when present, preferably represent at most 5% by weight in the heat transfer composition. Among the stabilizers, there may be mentioned in particular nitromethane, ascorbic acid, terephthalic acid, azoles such as tolutriazole or benzotriazole, phenol 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 butylglycidyl ether, hexanedioldiglycidyl ether, allylglycidyl ether, butylphenylglycidyl ether, phosphites, phosphonates, thiols and lactones.

As tracer agents (which can be detected) mention may be made of deuterated hydrofluorocarbons or not, deuterated hydrocarbons, perfluorocarbons, fluoroethers, brominated compounds, iodinated compounds, alcohols, aldehydes, ketones, nitrous oxide and combinations thereof. The tracer agent is different from the one or more heat transfer compounds composing the heat transfer fluid.

As solubilizing agents, mention may be made of hydrocarbons, dimethyl ether, polyoxyalkylene ethers, amides, ketones, nitriles, chlorocarbons, esters, lactones, aryl ethers, fluoroethers and magnesium compounds. 1-trifluoroalkanes. The solubilizing agent is different from the one or more heat transfer compounds composing the heat transfer fluid.

As fluorescent agents, mention may be made of naphthalimides, perylenes, coumarins, anthracenes, phenanthracenes, xanthenes, thioxanthenes, naphthoxanhthenes, fluoresceins and derivatives and combinations thereof.

As odorants, mention may be made of alkyl acrylates, allyl acrylates, acrylic acids, acrylresters, alkyl ethers, alkyl esters, alkynes, aldehydes, thiols, thioethers, disulfides, allyl isothiocyanates and alkanoic acids. , amines, norbornenes, norbornene derivatives, cyclohexene, heterocyclic aromatic compounds, ascaridole, o-methoxy (methyl) phenol and combinations thereof.

The heat transfer method according to the invention is based on the use of an installation comprising a vapor compression circuit which contains a heat transfer composition (i.e. a heat transfer fluid and at least one lubricating oil ). The heat transfer process may be a method of heating or cooling a fluid or a body.

The vapor compression circuit includes at least one evaporator, a compressor, a condenser and an expander, and fluid transport lines between these elements. The evaporator and the condenser comprise a heat exchanger allowing a heat exchange between the heat transfer fluid and another fluid or body. As a compressor, it is possible to use in particular a centrifugal compressor with one or more stages or a mini centrifugal compressor. Rotary, piston or screw compressors can also be used. The compressor may be driven by an electric motor or by a gas turbine (eg powered by vehicle exhaust, for mobile applications) or by gearing.

The facility may include a turbine to generate electricity (Rankine cycle).

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

The installation may also optionally include two or more vapor compression circuits containing identical or different heat transfer fluids. For example, the vapor compression circuits may be coupled together.

The vapor compression circuit operates in a conventional vapor compression cycle. The cycle comprises changing the state of the heat transfer fluid from a liquid phase (or two-phase liquid / vapor) to a vapor phase at a relatively low pressure, and then compressing the fluid in the vapor phase to a relatively high pressure. high, the change of state (condensation) of the heat transfer fluid from the vapor phase to the liquid phase at a relatively high pressure, and the reduction of the pressure to restart the cycle.

In the case of a cooling process, heat from the fluid or the body that is cooled (directly or indirectly, via a coolant) is absorbed by the heat transfer fluid, during the evaporation of the latter, and this at a relatively low temperature compared to the environment. Cooling processes include air conditioning processes (with mobile installations, for example in vehicles, or stationary), refrigeration and freezing or cryogenics.

In the case of a heating process, heat is transferred (directly or indirectly via a heat transfer fluid) from the heat transfer fluid, during the condensation thereof, to the fluid or to the body that is heating, and this at a relatively high temperature compared to the environment. The installation for implementing the heat transfer is called in this case "heat pump".

It is possible to use any type of heat exchanger for the implementation of heat transfer fluids according to the invention, and in particular co-current heat exchangers or, preferably, heat exchangers against -current. It is also possible to use microchannel exchangers.

The invention makes it possible in particular to implement cooling processes at moderate temperature, that is to say in which the temperature of the fluid or of the cooled body is from -15 ° C. to 15 ° C., preferably from -15 ° C. to 15.degree. 10 ° C to 10 ° C, more preferably from -5 ° C to 5 ° C

(ideally about 0 ° C).

The invention also makes it possible to implement heating processes at a moderate temperature, that is to say in which the temperature of the fluid or of the heated body is from 30 ° C. to 80 ° C., and preferably 35 ° C. C to

55 ° C, more preferably from 40 ° C to 50 ° C (most preferably about 45 ° C).

In the processes of "cooling or heating at moderate temperature" mentioned above, the inlet temperature of the heat transfer fluid to the evaporator is preferably from -20 ° C. to 10 ° C., especially from -15 ° C. ° C at 5 ° C, more preferably at -10 ° C to 0 ° C and for example about -5 ° C; and the temperature of the onset of condensation of the heat transfer fluid at the condenser is preferably 25 ° C to 90 ° C, especially 30 ° C to 70 ° C, more preferably 35 ° C to 55 ° C C and for example about 50 ° C. These processes may be refrigeration, air conditioning or heating processes.

The invention also makes it possible to implement processes of low temperature refrigeration processes, that is to say in which the temperature of the fluid or of the cooled body is from -40 ° C. to -10 ° C., and preferably from -35 ° C to -25 ° C, more preferably from -30 ° C to -20 ° C (most preferably about -25 ° C).

In the "low temperature refrigeration" processes mentioned above, the inlet temperature of the heat transfer fluid to the evaporator is preferably from -45 ° C. to -15 ° C., especially from -40 ° C. at -20 ° C, more preferably -35 ° C to -25 ° C and for example about -30 ° C; and the temperature of the onset of condensation of the heat transfer fluid at the condenser is preferably from 25 ° C to 80 ° C, in particular from 30 ° C to 60 ° C, more preferably from 35 ° C to 55 ° C and for example about 40 ° C.

It should be noted that the addition of HFC-134a in a heat transfer fluid consisting of HFO-1234yf (or comprising HFO-1234yf) improves the miscibility of the heat transfer fluid with the lubricating oil, which is ie increases the threshold temperature of appearance of the immiscibility zone (defined as being the temperature from which the compounds in the liquid phase form an emulsion), and thus makes it possible to increase the possibilities of use of the fluid heat transfer, for example by allowing use at a higher condensing temperature.

More generally, the invention makes it possible to proceed to the replacement of any heat transfer fluid in all heat transfer applications, and for example in automobile air conditioning. For example, the heat transfer fluids and heat transfer compositions according to the invention can serve to replace:

1,1,1,2-tetrafluoroethane (R134a);

1,1-Difluoroethane (R152a);

1,1,1,3,3-pentafluoropropane (R245fa);

mixtures of pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a) and isobutane (R600a), namely R422;

chlorodifluoromethane (R22);

the mixture of 51.2% chloropentafluoroethane (R 15) and 48.8% chlorodifluoromethane (R 22), namely R 502;

- any hydrocarbon;

the mixture of 20% of difluoromethane (R32), 40% of pentafluoroethane (R125) and 40% of 1, 1, 1, 2-tetrafluoroethane (R134a), namely R407A;

the mixture of 23% of difluoromethane (R32), 25% of pentafluoroethane (R125) and 52% of 1, 1, 1, 2-tetrafluoroethane (R134a), namely R407C;

the mixture of 30% of difluoromethane (R32), 30% of pentafluoroethane (R125) and 40% of 1,1,1,2-tetrafluoroethane (R134a), namely R407F;

R1234yf (2,3,3,3-tetrafluoropropene);

R1234ze (1, 3,3,3-tetrafluoropropene). EXAMPLE

The following example illustrates the invention without limiting it.

In this example, the miscibility of HFO-1234yf, HFC-134a and their mixtures with a lubricating oil of the type PAG ND8 is studied.

An autoclave is placed in a glass vat, fed by a thermostatic bath of water or brine according to the test temperatures, from -30 ° C to + 80 ° C.

For each tested heat transfer fluid (mixture of HFO-1234yf and HFC-134a with given proportions), the heat transfer fluid is introduced into the autoclave. Then a first quantity of defined lubricating oil is added, and the mixture is stirred. The temperature in the autoclave is increased until an emulsion is obtained, signaling the non-miscibility of the mixture. Then the mixture is cooled, an additional amount of oil is introduced into the mixture, and iteratively is carried out.

This step makes it possible to produce, for each given HFO-1234yf / HFC-134a transfer fluid, a curve making it possible to visualize the zone of non-miscibility of the mixture with the oil PAG, as a function of the temperature.

Reciprocally, the exploitation of the data makes it possible to determine, for a given concentration of lubricating oil, the threshold temperature of immiscibility as a function of the proportion of HFC-134a in the mixture HFO-1234yf / HFC-134a. This is shown in Figure 1, for a quantity of lubricating oil of 17%.

When the mixture does not contain HFC-134a, the emulsion appears at a temperature of 26 ° C. When, on the other hand, the mixture does not contain HFO-1234yf, the emulsion appears at a temperature of 69 ° C. This makes it possible to draw a dashed theoretical line, representing the temperature expected for the appearance of an emulsion with a mixture of HFO-1234yf and HFC-134a, this being obtained by weighting the respective miscibility temperatures.

Experimentally, however, we note that the miscibility zone is larger than theoretically expected. This means that there is a synergistic effect between HFO-1234yf and HFC-134a with respect to miscibility with lubricating oil.

A similar result is obtained with a quantity of lubricating oil of 30% for example instead of 17%. We thus observe that the addition from 20% of HFC-134a to HFO-1234yf makes it possible to improve the miscibility zone of about ten degrees compared to the expected value.

Claims

A composition comprising 2,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane and polyalkylene glycol.

The composition of claim 1 wherein 2,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane and polyalkylene glycol are at least 95%, preferably at least 99%, more particularly preferred at least 99.9% of the composition.

The composition of claim 1 or 2 comprising from 1 to 99% polyalkylene glycol, preferably from 5 to 50%, more preferably from 10 to 40%, and most preferably from 15 to 35%.

Composition according to one of Claims 1 to 3, in which the weight ratio between 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane is from 1: 99 to 99: 1, preferably from 25:75 to 95: 5, more preferably from 50:50 to 92:8, and most preferably from 55:45 to 92:8.

Composition according to one of claims 1 to 4, wherein the polyalkylene glycol has a viscosity of 1 to 1000 centistokes at 40 ° C, preferably from 10 to 200 centistokes at 40 ° C, more preferably from 20 to 100 centistokes at 40 ° C and ideally 40 to 50 centistokes at 40 ° C.

Composition according to one of claims 1 to 5, further comprising: one or more additives chosen from heat transfer compounds, lubricants, stabilizers, surfactants, tracer agents, fluorescent agents, odorants, solubilising agents and mixtures thereof; preferably one or more additives chosen from stabilizers, surfactants, tracer agents, fluorescers, odorants, solubilizing agents and mixtures thereof.

Use of polyalkylene glycol as a lubricating oil in a vapor compression circuit, in combination with a heat transfer fluid comprising, preferably, a mixture of 2,3,3,3-tetrafluoropropene and , 1, 1, 2-tetrafluoroethane.

Use according to claim 7, wherein the polyalkylene glycol is used in an amount of from 1 to 99%, preferably from 5 to 50%, more preferably from 10 to 40%, and most preferably from 15 to 35%, based on to the sum of the polyalkylene glycol and the heat transfer fluid.

Use according to claim 7 or 8, wherein the weight ratio of 2,3,3,3-tetrafluoropropene to 1,1,1,2-tetrafluoroethane in the heat transfer fluid is from 1: 99 to 99: 1, preferably 25:75 to 95: 5, more preferably 50:50 to 92:8, and most preferably 55:45 to 92:8.

Use according to one of claims 7 to 9, wherein the polyalkylene glycol has a viscosity of 1 to 1000 centistokes at 40 ° C, preferably 10 to 200 centistokes at 40 ° C, more preferably 20 to 100 centistokes at 40 ° C and ideally 40 to 50 centistokes at 40 ° C.

A heat transfer apparatus comprising a vapor compression circuit containing a heat transfer composition which is a composition according to one of claims 1 to 6.

Installation according to claim 1 1, selected from mobile or stationary heat pump heating, air conditioning, refrigeration, freezing and Rankine cycles, and especially among automotive air-conditioning installations.

A method of heating or cooling a fluid or a body by means of a vapor compression circuit containing a heat transfer fluid, said method comprising successively at least partial evaporation of the heat, compression of the heat transfer fluid, at least partial condensation of the heat transfer fluid and expansion of the heat transfer fluid, wherein the heat transfer fluid is associated with a lubricating oil to form a heat transfer fluid. heat transfer composition, said heat transfer composition being a composition according to one of claims 1 to 6.

A method of reducing the environmental impact of a heat transfer facility comprising a vapor compression circuit containing an initial heat transfer fluid, said method comprising a step of replacing the initial heat transfer fluid in the vapor compression circuit by a final heat transfer fluid, the final heat transfer fluid having a GWP lower than the initial heat transfer fluid, wherein the final heat transfer fluid is associated with a lubricating oil for forming a heat transfer composition, said heat transfer composition being a composition according to one of claims 1 to 6.

15. Use of 1,1,1,2-tetrafluoroethane to increase the miscibility of 2,3,3,3-tetrafluoropropene with a lubricating oil.

The use according to claim 15, wherein the lubricating oil is polyalkylene glycol, and preferably has a viscosity of 1 to 1000 centistokes at 40 ° C, more preferably 10 to 200 centistokes at 40 ° C, way more particularly preferred from 20 to 100 centistokes at 40 ° C and most preferably 40 to 50 centistokes at 40 ° C.

17. Use according to claim 15 or 16, wherein the 1,1,1,2-tetrafluoroethane is used in a proportion of 1 to 99%, preferably 5 to 75%, more preferably 8 to 50% ideally from 8 to 45%, based on the sum of 1, 1, 1, 2-tetrafluoroethane and 2,3,3,3-tetrafluoropropene.

18. Kit comprising:

a lubricating oil comprising a polyalkylene glycol on the other hand;

for use in a heat transfer installation comprising a vapor compression circuit.