Use of tetrafluoropropene-based compositions

Abstract

The present invention relates to the use of a composition comprising a polyol ester-based lubricant and a refrigerant F comprising at least one tetrafluoropropene and at least one hydrofluorocarbon in a heat transfer system having a vapor compression circuit with an oil separator.

Description

[Technical Field]

[0001] The present invention relates to the use of compositions based on tetrafluoropropene and at least one lubricant in refrigeration, air conditioning and heat pumps. [Background technology]

[0002] The issue of substances that deplete the atmospheric ozone layer was discussed in Montreal, and a protocol to reduce the production and use of chlorofluorocarbons (CFCs) was signed, which was further amended to abandon CFCs and restrict other products, including hydrochlorofluorocarbons (HCFCs).

[0003] The refrigeration and air conditioning industries are investing heavily in replacing these refrigerants, and hydrofluorocarbons (HFCs) are on the market.

[0004] In the automotive industry, many countries have transitioned vehicle air conditioning systems from chlorofluorocarbon refrigerants (CFC-12) to hydrofluorocarbons (1,1,1,2-tetrafluoroethane, or HFC-134a), which are less harmful to the ozone layer. However, HFC-134a (GWP = 1430) is considered to have a high global warming potential relative to the targets set out in the Kyoto Protocol. A fluid's contribution to the greenhouse effect is quantified based on its GWP (Global Warming Potential), which summarizes its heating capacity, with carbon dioxide as the base value.

[0005] Hydrofluoroolefins (HFOs) have a low global warming potential and are believed to be able to achieve the targets set by the Kyoto Protocol.

[0006] [Patent Document 1] (Japanese Patent Laid-Open Publication No. 4-110388) discloses hydrofluoropropene as a heat transfer material.

[0007] The most commonly used refrigeration machines in industry are based on cooling by evaporation of a liquid refrigerant; after evaporation, the fluid is compressed, used for cooling, and then returned to a liquid state, repeating the cycle.

[0008] Lubricants are essential to ensure smooth operation of moving mechanical parts, particularly to lubricate the compressor bearings.

[0009] The lubricant (oil) comes into contact with the refrigerant present on the moving parts during each pass through the compressor, picking up a certain amount of it, and the refrigerant tends to carry the lubricant entrained into the evaporator during the cycle. To overcome this oil migration problem, it is known to use oil separation systems that can purge the lubricant carried from the high pressure section (at the compressor outlet) to the low pressure section (at the compressor inlet).

[0010] POE oils have excellent thermal stability and are miscible with HFOs, especially HFO-1234, so they are commonly used in heat transfer systems such as refrigeration and / or air conditioning.

[0011] However, because HFO-1234 has good solubility in POE oil, a problem occurs in heat transfer systems with oil separators: a relatively large amount of refrigerant is trapped in the oil. When the oil is purged, the refrigerant trapped at the compressor outlet is returned directly to the input side. This means that not all of the refrigerant is used in the refrigeration cycle, resulting in a net loss of equipment efficiency and insufficient lubrication of the compressor, especially screw compressors, which have a low oil volume. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 4-110388 Summary of the Invention [Problem to be solved by the invention]

[0013] Therefore, there is a need to provide new compositions that can overcome at least one of the above drawbacks. [Means for solving the problem]

[0014] The subject of the present invention is the use of a composition comprising a lubricant based on a polyol ester and a refrigerant fluid F comprising at least one tetrafluoropropene and at least one hydrofluorocarbon in a heat transfer system having a vapor compression circuit with an oil separator.

[0015] Throughout this specification, compound percentages are expressed as weight percent unless otherwise specified.

[0016] The compositions of the present invention have the advantage of being able to improve the efficiency of heat transfer systems having oil separators, particularly over HFO-1234 / POE oil compositions that do not contain hydrofluorocarbons.

[0017] The composition of the present invention also has the advantage that a larger amount of lubricating oil can be recovered in the separator than when HFO-1234yf is used alone, thereby reducing deterioration of the compressor lubricating oil.

[0018] As used herein, the term "inventive composition" refers to a composition comprising a polyol ester-based lubricant and a refrigerant fluid F comprising at least one tetrafluoropropene and at least one hydrofluorocarbon. The various compounds and their proportions in the compositions of the present invention are described in detail below.

[0019] refrigerant The refrigerant fluid F of the present invention comprises at least one tetrafluoropropene (HFO-1234) and at least one hydrofluorocarbon.

[0020] Among the tetrafluoropropenes, mention may be made of 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf) and 1,2,3,3-tetrafluoropropene (HFO-1234ye).

[0021] Preferred are the tetrafluoropropenes HFO-1234yf and HFO-1234ze.

[0022] The refrigerant fluid F of the present invention can be prepared by any known method, for example by simply mixing the components.

[0023] As used herein, "HFO-1234ze" refers to 1,3,3,3-trifluoropropene, regardless of whether it is cis (Z) or trans (E). The term "HFO-1234ze" includes cisHFO-1234ze, transHFO-1234ze, and all mixtures of these two isomers in any ratio.

[0024] As used herein, "HFO-1234yf" means 2,3,3,3-tetrafluoropropene.

[0025] As used herein, "HFO-1234ye" refers to 1,2,3,3-tetrafluoropropene, regardless of whether it is cis (Z) or trans (E). Thus, as used herein, the term "HFO-1234ye" covers cisHFO-1234ye, transHFO-1234ye, and all mixtures of the two isomers in any proportion.

[0026] In one embodiment of the invention, the hydrofluorocarbon is selected from the group consisting of dichloromethane (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.

[0027] In one embodiment of the present invention, the refrigerant F comprises at least one tetrafluoropropene (HFO-1234) selected from HFO-1234yf and HFO-1234ze, and at least one hydrofluorocarbon selected from the group consisting of dichloromethane (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.

[0028] In one embodiment of the invention, the refrigerant F comprises two tetrafluoropropenes, in particular HFO-1234yf and HFO-1234ze.

[0029] In particular embodiments, the refrigerant F of the present invention is a binary composition (composed of two heat transfer compounds), a ternary composition (composed of three heat transfer compounds), a quaternary composition (composed of four heat transfer compounds) or a quinary composition (composed of five heat transfer compounds).

[0030] Refrigerant F may or may not contain impurities. If impurities are present, the amount is 1% or less, preferably 0.5% or less, preferably 0.1% or less, more preferably 0.05% or less, preferably 0.01% or less.

[0031] In one embodiment of the invention, the refrigerant F consists essentially of two, three, four or five heat transfer compounds.

[0032] A preferred refrigerant composition F of the present invention comprises, or preferably consists of, the following mixture: TIFF0007752469000001.tif5582

[0033] A preferred refrigerant composition F of the present invention comprises, or preferably consists of, the following mixture: TIFF0007752469000002.tif112121

[0034] A preferred refrigerant composition F of the present invention comprises, or preferably consists of, the following mixture: TIFF0007752469000003.tif49149

[0035] A preferred refrigerant composition F of the present invention comprises, or preferably consists of, the following mixture: TIFF0007752469000004.tif16124

[0036] In the refrigerant fluid F of the present invention, the mass proportion of tetrafluoropropene, in particular HFO-1234yf and / or HFO-1234ze, may be, for example, 1 to 5% of the fluid, or 5 to 10% of the fluid, or 10 to 15% of the fluid, or 15 to 20% of the fluid, or 20 to 25% of the fluid, or 25 to 30% of the fluid, or 30 to 35% of the fluid, or 35 to 40% of the fluid, or 40 to 45% of the fluid, or 45 to 50% of the fluid, can be 50-55% of the fluid, or 55-60% of the fluid, or 60-65% of the fluid, or 65-70% of the fluid, or 70-75% of the fluid, or 75-80% of the fluid, or 80-85% of the fluid, or 85-90% of the fluid, or 90-95% of the fluid, or 95-99% of the fluid, or 99-99.5% of the fluid, or 99.5-99.9% of the fluid, or more than 99.9% of the fluid based on the total mass of the fluid.

[0037] The content of tetrafluoropropene, particularly HFO-1234yf and / or HFO-1234ze, in the refrigerant F can be between the above ranges, for example, 50-60% between 50-55% and 55-60%.

[0038] In a preferred embodiment, the mass proportion of tetrafluoropropenes, in particular HFO-1234yf and / or HFO-1234ze, in the refrigerant F is 70% or more, preferably between 70% and 95%, in particular between 75% and 90%, in particular between 75% and 78%.

[0039] In the refrigerant of the present invention, the amount of hydrofluorocarbon may be 1 to 5% of the fluid, or 5 to 10% of the fluid, or 10 to 15% of the fluid, or 15 to 20% of the fluid, or 20 to 25% of the fluid, or 25 to 30% of the fluid, or 30 to 35% of the fluid, or 35 to 40% of the fluid, or 40 to 45% of the fluid, or 45 to 50% of the fluid, or 50 to 55% of the fluid, or 55 to 60% of the fluid, or 60 to 65% of the fluid, or 65 to 70% of the fluid, or 70 to 75% of the fluid, or 75 to 80% of the fluid, or 80 to 85% of the fluid, or 85 to 90% of the fluid, or 90 to 95% of the fluid, or 95 to 99% of the fluid, or 99 to 99.5% of the fluid, or 99.5 to 99.9% of the fluid based on the total mass of the fluid. The content of hydrofluorocarbon in the refrigerant F can be varied within the above ranges, for example, from 50-55% and 55-60% to 50-60%.

[0040] In a preferred embodiment, the weight proportion of hydrofluorocarbons in the refrigerant F is not more than 70%, preferably not more than 50%, preferably between 10% and 30%, in particular between 18% and 27%, relative to the total weight of the fluid.

[0041] A preferred refrigerant composition F is: TIFF0007752469000005.tif167151

[0042] A preferred refrigerant F fluid comprises the above mixture in the concentrations set forth in the table above.

[0043] In one embodiment of the present invention, a preferred refrigerant composition is: HFO-1234yf and HFC-134a HFO-1234ze and HFC-134a HFO-1234yf, HFC-152a, and HFC-134a

[0044] In one embodiment of the present invention, the preferred refrigerant is: HFO-1234yf and HFC-134a HFO-1234ze and HFC-134a HFO-1234yf, HFC-152a, and HFC-134a

[0045] In a preferred embodiment, refrigerant F comprises (preferably consists of) 75.5 to 79.5 wt.% HFO-1234yf, 12 to 16 wt.% HFC-152a, and 6.5 to 10.5 wt.% HFC-134a. In particular, refrigerant F comprises (preferably consists of) 77.5 wt.% HFO-1234yf, 14 wt.% HFC-152a, and 8.5 wt.% HFC-134a, relative to the total amount of fluid F.

[0046] In a preferred embodiment, the refrigerant F comprises (preferably consists of) 74 to 81.5 wt. % HFO-1234yf, 6.5 to 10.5 wt. % HFC-134a, and 12 to 16 wt. % HFC-152a, based on the total weight of the fluid F.

[0047] Whether a mixture is azeotropic or azeotrope-like (near-azeotropic) can be identified from the saturation pressures of the liquid and vapor at a given temperature.

[0048] In this specification, "vapor saturation pressure" or "P SAT VAP The term "dew pressure" refers to the pressure at which a drop of liquid first begins to form a vapor state of the fluid. This pressure is also called the dew pressure.

[0049] As used herein, the term "liquid saturation pressure" or "P SAT LIQThe term "pressure" refers to the pressure at which vapor bubbles first begin to form a liquid fluid. This pressure is also called bubble pressure.

[0050] Percent R calculated herein from the saturated vapor pressure of the vapor and liquid P corresponds to the following formula: TIFF0007752469000006.tif1263

[0051] In the present invention, the ratio R P The mixture is said to be azeotropic when the

[0052] In the present invention, the range "between X and Y" includes the limits X and Y. For example, the range "between 0 and 0.50%" includes the values ​​0 and 0.5%.

[0053] In the present specification, the ratio R p is strictly greater than 0.5% and strictly less than 10.0%, the mixture is an azeotrope-like mixture.

[0054] For example, the mixture in the table below is classified as an azeotrope according to ASHRAE 34-2013, "Designation and Safety Classification of Refrigerants." In this standard, the components, composition, and temperature are given in the same format, and the pressure is calculated using Refrop 9 (Reference Fluid Properties), a software developed by NIST (National Institute of Standards and Technology) to calculate the properties of refrigerants. p is a two-digit approximation).

[0055] TIFF0007752469000007.tif76142

[0056] This table specifically shows azeotropic refrigerants with a relative difference in saturation pressure of 0.5% or less.

[0057] Some of the refrigerants F according to the invention have the advantage of being azeotropic or near-azeotropic mixtures. TIFF0007752469000008.tif141141

[0058] TIFF0007752469000009.tif107136

[0059] In a preferred embodiment, the refrigerant fluid F comprises (preferably consists of) 74 to 81.5% by weight of HFO-1324yf, 6.5 to 10.5% by weight of HFC-134a, and 12 to 16% by weight of HFC-152a, relative to the total weight of the composition, - It is an azeotropic composition at temperatures between 40.00 and 70.00°C and pressures between 0.5 and 21.0 bar (±0.5%).

[0060] In a preferred embodiment, a refrigerant F comprising (preferably consisting of) 75.5% to 79.5% by weight of HFO-1324yf, 6.5 to 10.5% by weight of HFC-134a, and 12 to 16% by weight of HFC-152a, relative to the total weight of the composition, is an azeotropic composition at temperatures between -40.00 and 70.00°C and pressures between 0.5 and 21.0 bar (±0.5%).

[0061] A preferred refrigerant F is the following azeotropic composition: TIFF0007752469000010.tif143136

[0062] A preferred refrigerant F is the following azeotropic composition: TIFF0007752469000011.tif144125

[0063] A preferred refrigerant F is the following azeotropic composition: TIFF0007752469000012.tif136127

[0064] A preferred refrigerant F is the following azeotropic composition: TIFF0007752469000013.tif138131

[0065] A preferred refrigerant F is the following azeotropic composition: TIFF0007752469000014.tif139131

[0066] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 77.5% by weight (±0.2%) HFO-1234yf, 14% by weight (±0.2%) HFC-152a, and 8.5% by weight (±0.2%) HFC-134a, based on the total weight of the composition, and which composition has a boiling point between -40.00°C and 70.00°C at a pressure between 0.5 and 21.0 bar absolute (±0.5%).

[0067] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 77.5% by weight (±0.2%) HFO-1234yf, 14% by weight (±0.2%) HFC-152a, and 8.5% by weight (±0.2%) HFC-134a, based on the total weight of the composition, and has a boiling point of 26.97°C (±0.50°C) at a pressure of 7.3 bar absolute (±0.5%).

[0068] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 77.5 wt.% HFO-1234yf, 16 wt.% HFC-152a, and 6.5 wt.% HFC-134a, based on the total weight of the composition. This composition has a boiling point of -40.00°C to 70.00°C (±0.5%) at a pressure between 0.5 and 21.0 bar absolute, preferably between 0.6 and 20.9 bar absolute (±0.5%).

[0069] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 77.5 wt.% HFO-1234yf, 16 wt.% HFC-152a, and 6.5 wt.% HFC-134a, based on the total weight of the composition. This composition has a boiling point of 26.97°C (±0.5%) at a pressure between 7.3 bar absolute (±0.5%).

[0070] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 77.5% by weight (±0.2%) HFO-1234yf, 15.8% by weight (±0.2%) HFC-152a, and 6.7% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point between -40.00°C and 70.00°C (±0.5%) at a pressure between 0.5 and 21.0 (±0.5%) bar absolute, preferably between 0.6 and 20.9 bar absolute (±0.5%).

[0071] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 77.5% by weight (±0.2%) HFO-1234yf, 15.8% by weight (±0.2%) HFC-152a, and 6.7% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point of 26.97°C (±0.5%) at a pressure between 7.3 (±0.5%) bar (absolute).

[0072] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 81.5% by weight (±0.2%) HFO-1234yf, 12% by weight (±0.2%) HFC-152a, and 6.5% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point between -40.00°C and 70.00°C (±0.5%) at a pressure between 0.5 and 21.0 (±0.5%) bar absolute, preferably between 0.6 and 20.9 bar absolute (±0.5%).

[0073] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 81.5% by weight (±0.2%) HFO-1234yf, 12% by weight (±0.2%) HFC-152a, and 6.5% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point of 26.97°C (±0.50%) at a pressure between 7.3 (±0.5%) (bar absolute).

[0074] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 75.5% by weight (±0.2%) HFO-1234yf, 14.5% by weight (±0.2%) HFC-152a, and 10% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point between -40.00°C and 70.00°C (±0.5%) at a pressure between 0.5 and 21.0 (±0.5%) bar absolute, preferably between 0.78 and 20.98 bar absolute (±0.5%).

[0075] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 75.5% by weight (±0.2%) HFO-1234yf, 14.5% by weight (±0.2%) HFC-152a, and 10% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point of 26.97°C (±0.5%) at a pressure between 7.3 (±0.5%) (bar absolute).

[0076] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 75.5% by weight (±0.2%) HFO-1234yf, 12% by weight (±0.2%) HFC-152a, and 10.5% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point between -40.00°C and 70.00°C (±0.5%) at a pressure between 0.5 and 21.0 (±0.5%) bar absolute, preferably between 0.61 and 21.00 (±0.5%) bar absolute.

[0077] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 75.5% by weight (±0.2%) HFO-1234yf, 12% by weight (±0.2%) HFC-152a, and 10.5% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point of 26.97°C (±0.5%) at a pressure between 7.3 (±0.5%) (bar absolute).

[0078] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 75.5% by weight (±0.2%) HFO-1234yf, 12.2% by weight (±0.2%) HFC-152a, and 10.3% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point between -40.00°C and 70.00°C (±0.5%) at a pressure between 0.5 and 21.0 (±0.5%) bar absolute, preferably between 0.61 and 21.00 (±0.5%) bar absolute.

[0079] In a preferred embodiment, the azeotropic composition of the present invention comprises (preferably consists of) 75.5% by weight (±0.2%) HFO-1234yf, 12.2% by weight (±0.2%) HFC-152a, and 10.3% by weight (±0.2%) HFC-134a, based on the total weight of the composition. This composition has a boiling point of 26.97°C (±0.5%) at a pressure between 7.3 (±0.5%) (bar absolute).

[0080] lubricant As used herein, the terms "lubricant," "lubricating oil," and "lubricating oil" have the same meaning.

[0081] The lubricants of the present invention comprise one or more polyol esters. In one embodiment of the present invention, the polyol ester is obtained by reacting a carboxylic acid or a mixture of carboxylic acids with at least one polyol. In the present invention, unless otherwise specified, the term "polyol" means a compound containing at least two hydroxyl groups (-OH).

[0082] Esterified polyol (A) In one embodiment of the present invention, the polyol ester of the present invention corresponds to the following formula (I): R 1 [OC(O)R 2 ]n (I) (where, R 1is a linear or branched hydrocarbon group, optionally substituted with at least one hydroxyl group and / or containing at least one heteroatom selected from the group consisting of -O-, -N- and -S-; Each R 2 are independently selected from the group consisting of: i) H ii) aliphatic hydrocarbon groups iii) Branched chain hydrocarbon groups. iv) a mixture of the above ii) and / or iii) with an aliphatic hydrocarbon having 8 to 14 carbon atoms; n is an integer of at least 2) As used herein, the term "hydrocarbon group" means a group consisting of carbon and hydrogen atoms.

[0083] In one embodiment of the present invention, the polyol has the following general formula (II): R 1 (OH)n (II) (where, R 1 is a linear or branched hydrocarbon group, optionally substituted with at least one hydroxyl, preferably two hydroxyl groups, and / or may contain at least one heteroatom selected from the group consisting of -O-, -N- and -S-; n is an integer of at least 2)

[0084] Preferably, R 1 is a straight or branched chain hydrocarbon group containing 4 to 40 carbon atoms, preferably 4 to 20 carbon atoms. Preferably, R 1 is a straight or branched chain hydrocarbon group containing at least one oxygen atom. Preferably, R 1 is a straight or branched chain hydrocarbon group containing 4 to 10 carbon atoms, preferably 5 carbon atoms, substituted with two hydroxyl groups.

[0085] In a preferred embodiment, the polyol contains 2 to 10 hydroxyl groups, preferably 2 to 6 hydroxyl groups. The polyols of the present invention may contain one or more oxyalkylene groups, a particular case of which is the polyether polyols.

[0086] The polyol of the present invention may contain one or more nitrogen atoms. For example, the polyol may be an alkanolamine having 3 to 6 OH groups. Preferably, the polyol is an alkanolamine containing at least two, preferably at least three OH groups.

[0087] Preferred polyols for the present invention 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, glycerol, trimethylolpropane, sorbitol, hexaglycerol, and mixtures thereof.

[0088] The carboxylic acids of the present invention may have the following general formula (III): R 2 COOH(III) (where: R 2 is selected from the group consisting of: i) H ii) aliphatic hydrocarbon groups iii) Branched chain hydrocarbon groups. iv) a mixture of the above ii) and / or iii) with an aliphatic hydrocarbon having 8 to 14 carbon atoms;

[0089] Preferably, R 2 is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms, and particularly 1 to 6 carbon atoms. Preferably, R 2is a branched chain hydrocarbon group having 5 to 14 carbon atoms, preferably 6 to 8 carbon atoms, and especially 4 to 20 carbon atoms.

[0090] In a preferred embodiment, the branched hydrocarbon group has the following formula (IV): -C(R 3 )R 4 )(R 5 ) (IV) (where, R 3 , R 4 and R 5 are each independently an alkyl group, at least one of which contains at least two carbon atoms. Such branched alkyl groups, when attached to a carboxyl group, are called "neo groups" and the corresponding acids are called neo acids. 3 and R 4 is methyl and R 10 is an alkyl group containing at least two carbon atoms)

[0091] In the present invention, the group R 2 is one or more carboxy or -COOR 6 This R 6 represents an alkyl, hydroxyalkyl or hydroxyalkylalkyl group. Preferably, the acid R of formula (III) 2 COOH is a monocarboxylic acid.

[0092] Examples of carboxylic acids in which the hydrocarbon group is aliphatic include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, and heptanoic acid. Examples of carboxylic acids in which the hydrocarbon group 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.

[0093] A third type of carboxylic acid that can be used in the preparation of the polyol esters of formula (I) is a carboxylic acid having an aliphatic hydrocarbon group containing 8 to 14 carbon atoms, examples of which include decanoic acid, dodecanoic acid, lauric acid, stearic acid, myristic acid, and behenic acid. Among the dicarboxylic acids, examples include maleic acid, succinic acid, adipic acid, and sebacic acid.

[0094] In a preferred embodiment, the carboxylic acids used to prepare the esters of the polyols of formula (I) are a mixture of monocarboxylic and dicarboxylic acids, with the monocarboxylic acids predominating. The presence of dicarboxylic acids results in the formation of polyol esters with high viscosity.

[0095] In particular, the reaction of a carboxylic acid with a polyol to form the polyol ester of formula (I) is an acid-catalyzed reaction, which is reversible and can be completed by using a large amount of acid or by removing the water formed during the reaction.

[0096] The esterification reaction can be carried out in the presence of an organic or inorganic acid such as sulfuric acid, phosphoric acid, etc. The reaction is preferably carried out in the absence of a catalyst.

[0097] The amounts of carboxylic acid and polyol can be varied in the mixture depending on the desired result. In the special case where all hydroxyl groups are esterified, enough carboxylic acid is added to react with all the hydroxyl groups.

[0098] In one embodiment of the invention, a mixture of carboxylic acids is used, which can be reacted sequentially with the polyol.

[0099] In a preferred embodiment, when a mixture of carboxylic acids is used, one polyol is reacted first with a carboxylic acid, typically the carboxylic acid having the higher molecular weight, followed by reaction with a carboxylic acid having an aliphatic hydrocarbon chain.

[0100] In one embodiment of the present invention, the esters can be formed by reacting a polyol with a carboxylic acid (or its anhydride or ester derivative) in the presence of an acid at elevated temperature, while removing water formed during the reaction. Typically, the reaction can be carried out at a temperature of 75 to 200°C.

[0101] In another embodiment, the ester of the polyol formed contains hydroxyl groups that are not fully reacted, in this case a partially esterified polyol ester.

[0102] In a preferred embodiment, the polyol ester is obtained from pentaerythritol alcohol and a mixture of carboxylic acids: isononanoic acid, at least one acid having an aliphatic hydrocarbon group with 8 to 10 carbon atoms, and heptanoic acid. A preferred polyol ester is obtained from pentaerythritol and a mixture of 70% isononanoic acid, 15% of at least one carboxylic acid having an aliphatic hydrocarbon group with 8 to 10 carbon atoms, and 15% heptanoic acid. An example of such an oil is Solest 68, available from CPI Engineering Services, Inc.

[0103] Polyol ester (B) In another embodiment, the polyol ester of the present invention comprises at least one ester of one or more branched carboxylic acids having up to 8 carbon atoms, the ester being obtainable by reaction of the above branched carboxylic acids with one or more polyols.

[0104] Preferably, the branched chain carboxylic acid contains at least 5 carbon atoms, in particular, the branched chain carboxylic acid contains 5 to 8 carbon atoms, preferably 5 carbon atoms.

[0105] Preferably, the branched chain carboxylic acid does not contain 9 carbon atoms. In particular, the branched chain carboxylic acid is not 3,5,5-trimethylhexanoic acid.

[0106] In a preferred embodiment, the branched chain carboxylic acid is selected from 2-methylbutanoic acid, 3-methylbutanoic acid, and mixtures thereof.

[0107] In a preferred embodiment, the polyol is selected from the group consisting of neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, and mixtures thereof.

[0108] In a preferred embodiment, the polyol ester is obtained from: i) a carboxylic acid selected from 2-methylbutanoic acid, 3-methylbutanoic acid, and mixtures thereof; ii) A polyol selected from the group consisting of neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, and mixtures thereof.

[0109] Preferably, the polyol ester is derived from 2-methylbutanoic acid and pentaerythritol. Preferably, the polyol ester is derived from 2-methylbutanoic acid and dipentaerythritol. Preferably, the polyol ester is derived from 3-methylbutanoic acid and pentaerythritol. Preferably, the polyol ester is derived from 3-methylbutanoic acid and dipentaerythritol. Preferably, the polyol ester is derived from 2-methylbutanoic acid and neopentyl glycol.

[0110] Polyol ester (C) In another embodiment, the polyol ester of the present invention is an ester of poly(neopentyl polyol) obtained from: i) a neopentyl polyol having the formula (V): TIFF0007752469000015.tif2770 (where, each R independently represents CH, CH, or CHOH; p is an integer ranging from 1 to 4 with at least one monocarboxylic acid having 2 to 15 carbon atoms in a 1:1 molar ratio of hydroxyl groups to carboxyl groups in the presence of an acid catalyst to form a partially esterified poly(neopentyl) polyol composition; ii) The partially esterified poly(neopentyl) polyol composition obtained at the end of step i) is reacted with another carboxylic acid having 2 to 15 carbon atoms to form the final poly(neopentyl polyol) ester composition.

[0111] The reaction of i) is preferably carried out at a molar ratio of 1:4 to 1:2.

[0112] Preferably, the neopentyl polyol has the following formula (VI): TIFF0007752469000016.tif2248 (where, Each R is independently CH3, C2H5, or CH2OH.

[0113] Preferred neopentyl polyols are selected from pentaerythritol, dipentaerythritol, tripentaerythritol, tetraerythritol, trimethylolpropane, trimethylolethane, neopentyl glycol, and in particular the neopentyl polyol is pentaerythritol.

[0114] It is preferred to use a single neopentyl polyol to produce POE-based lubricants. In some cases, two or more neopentyl polyols are used. This is particularly the case with commercial products of pentaerythritol, which also contain small amounts of dipentaerythritol, tripentaerythritol, and tetraerythritol.

[0115] In a preferred embodiment, the monocarboxylic acid contains 5 to 11 carbon atoms, preferably 6 to 10 carbon atoms.

[0116] The monocarboxylic acids have in particular the following general formula (VII): R'C(O)OH (VII) (where, R' is a straight or branched chain C1-C12 alkyl group, C6-C12 aryl, or C6-C30 aralkyl group. Preferably, R' is a C4-C10 alkyl group, preferably a C5-C9 alkyl group.

[0117] The monocarboxylic acid is in particular 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-trimethylbenzyl alcohol, benzoic acid and mixtures thereof.

[0118] In a preferred embodiment, the monocarboxylic acid is n-heptanoic acid or a mixture of n-heptanoic acid with other linear monocarboxylic acids, particularly n-octanoic acid and / or n-decanoic acid. This mixture of monocarboxylic acids can contain 15-100 mol% heptanoic acid and 85-0 mol% monocarboxylic acids. In particular, this mixture is 75-100 mol% heptanoic acid and 25-0 mol% octanoic acid and decanoic acid (molar ratio 3:2).

[0119] In a preferred embodiment, the polyol ester comprises: i) 45% to 55% by weight of an ester of monopentaerythritol and at least one monocarboxylic acid having 2 to 15 carbon atoms; ii) at least 13% by weight of an ester of dipentaerythritol with at least one monocarboxylic acid having 2 to 15 carbon atoms; iii) 10% by weight or less of an ester of tripentaerythritol and at least one monocarboxylic acid having 2 to 15 carbon atoms; iv) Esters of at least 25% by weight of other oligomers of tetraerythritol and pentaerythritol with at least one monocarboxylic acid having 2 to 15 carbon atoms.

[0120] Polyol ester (D) In another embodiment, the polyol ester of the present invention has the following formula (VIII): TIFF0007752469000017.tif58121

[0121] (where, R 7 , R 8 , R 9 , R 10 , R 11 and R 12 are independently H or CH3, a, b, c, y, x, and z are each independently an integer, and a+x, b+y, and c+z are each independently an integer ranging from 1 to 20; R 13 , R 14 and R 15 are independently selected from aliphatic or branched alkyl groups, alkenyl groups, cycloalkyl, aryl, alkylaryl, arylalkyl, alkylcycloalkyl, cycloalkylalkyl, arylcycloalkyl, cycloalkylaryl, alkylcycloalkylaryl, alkylarylcycloalkyl, arylcycloalkylalkyl, arylalkylcycloalkyl, cycloalkylalkylaryl and cycloalkylarylalkyl; R 13 , R 14 and R 15 has 1 to 17 carbon atoms and may be optionally substituted)

[0122] In a preferred embodiment, R 13 , R 14 and R 15 Each of R is a linear or branched alkyl, alkenyl, or cycloalkyl group, and these alkyl, alkenyl, or cycloalkyl groups may contain at least one heteroatom selected from N, O, Si, F, or S, and preferably R 13 , R 14 and R 15Each of these independently has 3 to 8 carbon atoms, preferably 5 to 7 carbon atoms.

[0123] Preferably, a+x, b+y and c+z are each independently an integer in the range of 1-10, preferably 2-8, more preferably 2-4. R 7 , R 8 , R 9 , R 10 , R 11 and R 12 is preferably H.

[0124] The polyol ester of the above formula (VIII) can generally be produced by the method described in

[0027] to

[0030] of International Application WO2012 / 177742.

[0125] In particular, polyol esters of formula (VIII) are obtainable by esterification of glycerol alkoxylates with one or more monocarboxylic acids having 2 to 18 carbon atoms (as described in paragraph

[0027] of International Application WO2012 / 177742).

[0126] In a preferred embodiment, the monocarboxylic acid has one of the following formulas: R 13 -COOH R 14 COOH R 15 COOH (where R 13 , R 14 and R 15 is defined above) Also, derivatives of carboxylic acids, anhydrides, esters and acyl halides can be used.

[0127] The esterification can be carried out with one or more monocarboxylic acids. Preferred monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutanoic acid, pivalic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, 3,3,5-trimethylisothiazolinone, 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, oxalic acid, abietic acid, undecenoic acid, lauric acid, undecylenic acid, linolenic acid, arachidic acid, behenic acid, tetrahydrobenzoic acid, 2-ethylhexanoic acid, furoic acid, benzoic acid, 4-acetylbenzoic acid, pyruvic acid, 4-tert-butylbenzoic acid, naphthenic acid, 2-methylbenzoic acid, salicylic acid, isomers, methyl esters and mixtures thereof.

[0128] Preferably, 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-trimethyl, 2-ethylhexanoic acid, n-octanoic acid, n-nonanoic acid and isononanoic acid.

[0129] Preferably, the esterification is carried out with one or more monocarboxylic acids selected from the group consisting of butyric acid, isobutyric acid, n-valeric acid, 2-methylbutanoic acid, 3-methylbutanoic acid, n-hexane, n-heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid, 3,3,5-trimethylisothiazolinone, n-nonanoic acid, decanoic acid, undecanoic acid, undecelenic acid, lauric acid, stearic acid, isostearic acid, and mixtures thereof.

[0130] In another embodiment, the polyol ester of the present invention has the following formula (IX): TIFF0007752469000018.tif26119

[0131] (where, R 17 and R 18are each independently H or CH3; m and n are each independently an integer, and m+n is an integer ranging from 1 to 10; R 16 and R 19 are independently selected from the group consisting of aliphatic or branched alkyl, alkenyl, cycloalkyl, aryl, alkylaryl, arylalkyl, cycloalkylalkyl, arylcycloalkyl, alkylcycloalkyl, cycloalkylaryl, alkylcycloalkylaryl, alkylarylcycloalkyl, arylcycloalkylalkyl, arylalkylcycloalkyl, cycloalkylalkylaryl and cycloalkylarylalkyl; R 16 and R 19 has 1 to 17 carbon atoms and may be optionally substituted)

[0132] In a preferred embodiment, R 16 and R 19 Each of R independently represents a straight or branched chain alkyl group, alkenyl group, or cycloalkyl group, and these alkyl, alkenyl, or cycloalkyl groups may contain at least one heteroatom selected from N, O, Si, F, or S. Preferably, R 16 and R 19 Each of these independently has 3 to 8 carbon atoms, preferably 5 to 7 carbon atoms.

[0133] In a preferred embodiment, R 17 and R 18 each of is H, and / or m+n is an integer from 2 to 8, 4 to 10, 2 to 5, or 3 to 5, in particular, m+n is 2, 3, or 4.

[0134] In a preferred embodiment, the polyol ester of formula (IX) is a diester of triethylene glycol, a diester of tetraethylene glycol, in particular a diester with one or two monocarboxylic acids having from 4 to 9 carbon atoms.

[0135] The polyol ester of formula (IX) can be prepared by esterifying ethylene glycol, propylene glycol, or an oligo- or polyalkylene glycol (which can be an oligo- or polyethylene glycol, an oligo- or polypropylene glycol, or a copolymer having an ethylene glycol-propylene glycol block) with one or two monocarboxylic acids having 2 to 18 carbon atoms. This esterification reaction can be carried out in the same manner as the esterification reaction for preparing the polyol ester of formula (VIII).

[0136] In particular, the preparation of the polyol ester of formula (IX) can employ the same monocarboxylic acids as those used in preparing the polyol ester of formula (VIII) above.

[0137] In one embodiment of the present invention, the polyol ester based lubricant of the present invention comprises 20-80 wt. %, preferably 30-70 wt. %, preferably 40-60 wt. % of at least one polyol ester of formula (VIII) and 80-20 wt. %, preferably 70-30 wt. %, preferably 60-40 wt. % of at least one polyol ester of formula (IX).

[0138] Generally, some alcohol functional groups remain esterified during the esterification reaction, but the proportion is small. Thus, PEO can contain 0-5% CHOH per mole of -CH-OC(=O)- units.

[0139] The preferred POE lubricant of the present invention has a viscosity at 40°C of 1 to 1000 centistokes (cSt), preferably 10 to 200 cSt, more preferably 20 to 100 cSt, and preferably 30 to 80 cSt.

[0140] The international classification of oils is given by ISO standard 3448-1992 (NF T60-141), and each oil is designated by its average viscosity class measured at a temperature of 40°C.

[0141] composition In the composition of the present invention, the mass proportion of refrigerant F can be 1 to 5% of the composition, or 5 to 10% of the composition, or 10 to 15% of the composition, or 15 to 20% of the composition, or 20 to 25% of the composition, or 25 to 30% of the composition, or 30 to 35% of the composition, or 35 to 40% of the composition, or 40 to 45% of the composition, or 45 to 50% of the composition, or 50 to 55% of the composition, or 55 to 60% of the composition, or 60 to 65% of the composition, or 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, or 99 to 99.5% of the composition, or 99.5 to 99.9% of the composition, or 99.9% or more of the composition. The content of the catalyst F can be between two or more of the above ranges, for example, between 50-55% and 55-60%, that is, 50-60%.

[0142] In a preferred embodiment, the composition of the present invention contains refrigerant F in an amount of 50% by weight or more, in particular 50% to 99% by weight, relative to the total weight of the composition.

[0143] In the composition of the present invention, the weight proportion of the polyol ester lubricating oil (POE) is 1 to 5% of the composition, or 5 to 10% of the composition, or 10 to 15% of the composition, or 15 to 20% of the composition, or 20 to 25% of the composition, or 25 to 30% of the composition, or 30 to 35% of the composition, or 35 to 40% of the composition, or 40 to 45% of the composition, or 45 to 50% of the composition, or 50 to 55% of the composition, or 55 to 60% of the composition, or 60 to 65% of the composition, or 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, or 99 to 99.5% of the composition, or 99.5 to 99.9% of the composition, or 99.9% or more of the composition. The lubricant content can be between several of the above ranges, for example, between 50-55% and 55-60%, ie, 50-60%.

[0144] In one embodiment of the present invention, the composition of the present invention may comprise (1) and (2) the following: (1) A refrigerant F selected from the following group: HFO-1234yf / HFC-134a, HFO-1234ze / HFC-134a, HFO-1234yf / HFC-134a / HFC-152a (2) Lubricants based on at least one polyol ester (POE), in particular a polyol ester selected from the above polyol esters A), B), C) or D), in particular a polyol ester of formula (I), (VIII) or (XI)

[0145] In one embodiment of the present invention, the composition of the present invention may comprise (1) and (2) the following: (1) Refrigerant F containing one of the following mixtures: HFO-1234yf / HFC-134a HFO-1234ze / HFC-134a or HFO-1234yf / HFC-134a / HFC-152a (2) at least one lubricant based on polyol ester (POE), in particular selected from polyol esters A), B), C) or D), in particular polyol esters of formula (I), (VIII) or (XI)

[0146] In one embodiment of the present invention, the composition comprises: (1) and (2) (1) a refrigerant F comprising (preferably consisting of) a HFO-1234yf / HFC-134A / HFC-152a mixture, in particular 75.5 to 79.5% by weight of HFO-1234yf, 12 to 16% by weight of HFC-152a, and 6.5 to 10.5% by weight of HFC-134a, preferably 77.5% by weight of HFO-1234yf, 14% by weight of HFC-152a, and 8.5% by weight of HFC-134a; (2) Lubricants based on at least one polyol ester (POE), in particular polyol esters selected from polyol esters A), B), C) or D) or of formula (I), (VIII) or (XI).

[0147] The compositions of the present invention may contain one or more additives (which are not essentially heat transfer compounds in their intended use). The additive may be selected from nanoparticles, stabilizers, surfactants, tracer agents, fluorescent agents, flavoring agents and solubilizers. Preferably, the additive is not a lubricant.

[0148] In one embodiment of the present invention, the inventive composition is a heat transfer composition. Stabilizers, when present, may comprise up to 5% by weight of the heat transfer composition. Among the stabilizers, mention may be made of nitromethane, ascorbic acid, terephthalic acid, azoles such as tolyltriazole or benzotriazole, phenolic compounds such as tocopherol, hydroquinone, t-butylhydroquinone, 2,6-ditert-butyl-4-methylphenol, (fluorinated or perfluorinated alkyl or alkenyl or aromatic) epoxides such as n-butyl glycidyl ether, hexanediol diglycidyl ether, allyl glycidyl ether, butylphenyl ether, phosphites, phosphonates, thiols and lactones.

[0149] As nanoparticles, in particular carbon nanoparticles, metal oxides (copper, aluminum), TI02, Al2O3, MoS2 can be used.

[0150] Tracer agents (that can be detected) include deuterated (or undeuterated) hydrofluorocarbons, deuterated hydrocarbons, perfluorocarbons, fluoroethers, brominated compounds, iodinated compounds, alcohols, aldehydes, ketones, nitrous oxide, and combinations thereof. Tracer agents are distinct from the heat transfer components, including the heat transfer fluid (refrigerant F).

[0151] Solubilizing agents include hydrocarbons, dimethyl ethers, polyoxyalkylene ethers, amides, ketones, nitriles, chlorocarbons, esters, lactones, aryl ethers, fluoroethers, and 1,1,1-trifluoroalkanes. The solubilizing agents are compounds of heat transfer components, including heat transfer fluids (refrigerants F), and patents vary.

[0152] Fluorescent agents can include naphthalimides, perylenes, coumarins, anthracenes, phenanthracenes, xanthenes, thioxanthenes, naphthoxanthenes, fluoresceins, and derivatives and combinations thereof.

[0153] Flavoring agents may include alkyl acrylates, allyl acrylates, acrylic acids, acrylic esters, alkyl ethers, alkyl esters, alkynes, aldehydes, thiols, thioethers, disulfides, allyl isothiocyanates, alkanoic acids, amines, norbornene derivatives, norbornene, cyclohexene, aromatic heterocyclic compounds, ascaridole, O-methoxy(methyl)phenol, and combinations thereof.

[0154] "Heat transfer compound," "heat transfer fluid," or "refrigerant" means a compound or fluid capable of absorbing heat by vaporizing at low temperature and pressure in a vapor compression circuit and releasing heat by condensing at high temperature and pressure. Generally, a heat transfer fluid can include one, two, three, or more heat transfer compounds. In particular, refrigerant F is a heat transfer fluid.

[0155] "Heat transfer composition" means a composition comprising a heat transfer fluid and one or more additives that are not heat transfer compounds in the intended use. The compositions of the present invention are heat transfer compositions.

[0156] Purpose The present invention further relates to a method of heat transfer utilizing a heat transfer device comprising a vapor compression circuit containing the composition of the present invention as a heat transfer composition, said circuit having an oil separator, which method of heat transfer can be a method of heating or cooling a fluid or object.

[0157] The present invention further relates to the use of the above composition as a heat transfer fluid in a vapor compression system including an oil separator, preferably a screw compressor.

[0158] In one embodiment of the invention, the vapor compression system is one of the following: (1) Air conditioning systems, or (2) a refrigeration system, or (3) Refrigeration systems, or (4) Heat pump system.

[0159] The compositions of the present invention can further be used to generate mechanical work or electricity, particularly in processes for generating electricity by the Rankine cycle.

[0160] The invention further relates to a heat transfer system including a vapor compression circuit containing the composition of the present invention as a heat transfer composition, the compression circuit including an oil separator, and preferably including a screw compressor.

[0161] In one embodiment of the invention, the equipment is selected from mobile or stationary refrigeration, heating (heat pumps), air conditioning, refrigeration and combustion engines.

[0162] The installation can be a heat pump system, in which case the item or fluid to be heated (typically air, possibly one or more products, objects or organic matter) is located in a room or in the interior of a vehicle (if mobile). In a preferred embodiment, the installation is an air conditioning system, in which the fluid or item to be cooled (typically air, possibly one or more products, objects or organic matter) is located in the room or in the interior of a vehicle (if mobile). The installation can be a refrigeration system or a refrigeration plant (or cryogenic plant), in which case the fluid or body to be cooled is typically air, or one or more products, objects or objects located in a room or in a container.

[0163] The heat transfer equipment is in particular a heat pump or an air conditioning system, for example a chiller.

[0164] The present invention further relates to a method for heating or cooling a fluid or article by means of a vapor compression circuit containing a heat transfer composition, the method comprising sequentially evaporating the heat transfer composition, compressing the heat transfer composition, condensing the heat transfer composition, and expanding the heat transfer composition, the heat transfer composition being the composition of the present invention as described above, and the vapor compression circuit including an oil separator, particularly a screw compressor.

[0165] The invention further relates to a method for generating electricity using a heat engine, the method comprising sequentially evaporating a heat transfer composition, expanding the heat transfer composition in a turbine to generate electricity, condensing the heat transfer composition, and compressing the heat transfer composition, the heat transfer composition being the composition described above, and the method employing an oil separator.

[0166] The vapor compression circuit containing the heat transfer composition includes at least one evaporator, a compressor, preferably a screw compressor, an oil separator, a condenser, an expansion valve, and a heat transfer composition transport line between these components. The evaporator and condenser are equipped with heat exchangers for exchanging heat between the heat transfer composition and another fluid or article.

[0167] The evaporator used in the present invention may be a superheated evaporator or a flooded evaporator, in which all of the heat transfer composition is evaporated at the outlet of the evaporator and the vapor phase is superheated.

[0168] In a flooded evaporator, the liquid heat transfer composition does not completely vaporize. The flooded evaporator includes a separator between the liquid and vapor phases.

[0169] The compressors used can be single-stage or multi-stage centrifugal or mini-centrifugal compressors, as well as rotary or screw compressors with pistons.

[0170] In one embodiment of the present invention, the vapor compression circuit includes a centrifugal compressor, preferably a centrifugal compressor and a flooded evaporator.

[0171] In another embodiment, the vapor compression circuit comprises a screw compressor, preferably a twin or single screw compressor. In particular, the vapor compression circuit can be a twin screw compressor capable of producing a substantial flow of oil, e.g., 6.3 L / s.

[0172] Centrifugal compressors are characterized by the use of rotating elements to radially accelerate the heat transfer composition, typically comprising at least a rotor and a diffuser housed within an enclosure. The heat transfer composition is introduced at the center of the rotor and undergoes acceleration, causing it to flow to the periphery of the rotor. Thus, static pressure is increased on the one hand by the rotor and on the other hand by diffusion. Velocity is converted into an increase in static pressure. A rotor / diffuser set constitutes one stage of the compressor. Centrifugal compressors can have 1 to 12 stages depending on the desired final pressure and volume of the fluid to be processed.

[0173] Compression ratio is defined as the ratio of the absolute pressure at the output to the absolute pressure at the inlet of the heat transfer composition.

[0174] Large centrifugal compressors have a rotational speed of 3000-7000 rpm. Small centrifugal compressors (or mini centrifugal compressors) generally operate at a rotational speed of 40,000-70,000 rpm and have small rotors (generally less than 0.15 m).

[0175] Multi-stage rotors can be used to improve compressor efficiency and reduce energy costs (compared to single-stage rotors). In a two-stage system, the output of the first rotor stage feeds the input of the second rotor. Both rotors can be mounted on a single shaft. Each stage can achieve a fluid compression ratio of approximately 4:1; that is, the absolute pressure at the output can be four times the absolute pressure at the inlet. Examples of two-stage centrifugal compressors, particularly for automotive applications, are described in U.S. Pat. No. 5,065,990 and U.S. Pat. No. 5,363,674.

[0176] The centrifugal compressor may be driven by an electric motor or a gas turbine (eg, driven by the vehicle's exhaust gases in automotive applications) or a transmission.

[0177] The installation may include coupling an expander with a turbine to generate electricity (Rankine cycle).

[0178] The facility may further include at least one heat transfer fluid circuit used to transfer heat (with or without a change of state) between the heat transfer composition and a fluid or item to be heated or cooled.

[0179] The installation may further include two (or more) vapor compression circuits containing the same or different heat transfer compositions, which may, for example, be coupled together.

[0180] The vapor compression circuit operates according to a conventional vapor compression cycle, which involves changing the state of the heat transfer composition from a liquid phase (or a liquid / vapor two-phase) to a gas phase at a relatively low pressure, followed by compressing the composition back to the gas phase at a relatively high pressure, changing the state of the heat transfer composition from the gas phase to a liquid phase at a relatively high pressure (condensing), and then reducing the pressure again.

[0181] In the cooling mode, heat from the fluid or item being cooled (directly or indirectly via a heat exchange fluid) is absorbed by the heat transfer composition as it evaporates, resulting in a temperature relatively lower than the ambient temperature. Cooling processes include air conditioning (mobile or stationary, such as in a vehicle), refrigeration, and freezing or cryogenic processes. The air conditioning category includes residential, commercial, and industrial air conditioners, where the equipment used includes chillers or direct expansion units. The refrigeration category includes district and commercial refrigeration, refrigeration, food processing, and refrigerated transport (trucks, ships).

[0182] In the case of a heating process, the heat of the heat transfer composition is transferred (directly or indirectly via a heat transfer fluid) to a liquid or object that is heated at a relatively high temperature relative to the environment by condensation of the heat transfer composition. This is called a "heat pump". This can be a medium-temperature or high-temperature heat pump.

[0183] The heat transfer compositions of the present invention can be used in any type of heat exchanger, particularly in parallel flow heat exchangers or preferably in counter flow heat exchangers.

[0184] In a preferred embodiment, the present invention provides cooling and heating processes and related equipment that include a counter-flow heat exchanger, a condenser, or an evaporator. That is, the heat transfer compositions of the present invention are particularly effective in counter-flow heat exchangers. Preferably, both the evaporator and the condenser are equipped with counter-flow heat exchangers.

[0185] In the present invention, a "counterflow heat exchanger" refers to a heat exchanger in which heat is exchanged between a first fluid and a second fluid, in which the heat of the first fluid at the inlet of the heat exchanger is exchanged with the heat of the second fluid at the outlet of the heat exchanger, and the first fluid at the outlet of the heat exchanger exchanges heat with the second fluid at the inlet of the heat exchanger.

[0186] Counter-flow heat exchangers include, for example, devices in which the flow of a first fluid and a second fluid are in opposite or nearly opposite directions. Cross-mode exchangers operating in a counter-flow manner are included among counter-flow heat exchangers within the meaning of this application.

[0187] The compositions of the invention advantageously result in a higher superheat (difference between separator temperature and condenser temperature) at the compressor output than HFO-1234yf and / or HFO-1234ze under various operating conditions (air conditioning, refrigeration, heat pumps, etc.).

[0188] In the "low temperature cooling" process, the inlet temperature of the heat transfer composition in the evaporator is -45°C to -15°C, particularly -40°C to -20°C, preferably -35°C to -25°C, for example about -30°C, and the condensation start temperature of the heat transfer composition in the condenser is preferably 25°C to 80°C, particularly 30°C to 60°C, more preferably 35°C to 55°C, for example about 40°C.

[0189] In the "medium temperature cooling" process, the inlet temperature of the heat transfer composition in the evaporator is preferably -20°C to 10°C, particularly -15°C to 5°C, more preferably -10°C to 0°C, for example, about -5°C, and the condensation start temperature of the heat transfer composition in the condenser is preferably 25°C to 80°C, particularly 30°C to 60°C, more preferably 35°C to 55°C, for example, about 50°C. This process can be a refrigeration or air conditioning process.

[0190] In the "medium temperature heating" process, the inlet temperature of the heat transfer composition in the evaporator is -20°C to 10°C, particularly -15°C to 5°C, more preferably -10°C to 0°C, for example, about -5°C, and the condensation start temperature of the heat transfer composition in the condenser is 25°C to 80°C, preferably 30°C to 60°C, more preferably 35°C to 55°C, for example, about 50°C.

[0191] In the "high temperature heating" process, the inlet temperature of the heat transfer composition in the evaporator is -20 to 90°C, preferably 10 to 90°C, more preferably 50 to 90°C, for example, about 80°C, and the condensation start temperature of the heat transfer composition in the condenser is 70 to 160°C, preferably 90 to 150°C, more preferably 110 to 140°C, for example, about 135°C.

[0192] The compositions of the present invention are particularly advantageous for refrigerated transport.

[0193] This refers to refrigerated transport, where perishable goods are transported in a refrigerated space. Food and medicines are an important part of perishable goods.

[0194] Refrigerated transport can be accomplished using truck, rail, ship, or multi-platform containers that are compatible with truck, rail, and ship.

[0195] The temperature in the refrigerated space during refrigerated transport is between -30°C and 16°C. The amount of refrigerant filled when transporting by truck, rail or multi-platform container is 4-8 kg. In the case of shipboard equipment, it is 100-500 kg.

[0196] The most commonly used refrigerant today is R404A.

[0197] The operating temperature of a refrigeration unit is a function of the required refrigeration temperature and the external climatic conditions. The same refrigeration unit must be able to cover a wide range of temperatures from -30°C to 16°C, and must operate equally well in both cold and tropical climates. The most severe evaporation temperature condition is -30°C.

[0198] Oil Separator In the present invention, the vapor compression circuit has an oil separator.

[0199] In one embodiment of the present invention, the oil separator is disposed between the compressor and the condenser.

[0200] In the present invention, the oil separator can be a container or a cylindrical tube having at least one deflector or screen for collecting the oil.

[0201] In one embodiment of the present invention, the oil separator includes a float mechanism / valve / pointer. In this particular case, the oil collected by the separator is passed through a float mechanism / valve / pointer. side When the oil level is high enough to raise the float mechanism, a valve / pointer system opens and the oil is re-introduced into the compressor housing. This oil return is driven by the pressure differential between the oil separator and the compressor housing.

[0202] Advantageously, the oil separator can separate the lubricant from the refrigerant in the gaseous mixture of refrigerant and lubricant coming from the compressor. In particular, the oil separator can advantageously send the refrigerant to the condenser and return the separated lubricant to the compressor.

[0203] The compression circuit of the present invention includes an oil return line between the oil separator and the compressor inlet.

[0204] In particular, the oil separator has an inlet valve (to allow the inventive composition to enter), an outlet valve at the top of the separator (to allow recovery of a portion of the refrigerant going to the condenser), and an outlet valve at the bottom of the separator (to allow the discharge of oil back to the compressor).

[0205] Oil separators can typically be implemented by at least one of the following techniques: (1) Coalescence: The phenomenon of two identical but dispersed substances becoming one. (2) Centrifugation: This technique uses centrifugal force to separate liquids of different densities. (3) Deceleration: This technique allows the heaviest molecules to continue their path due to their inertia, while the lighter molecules are allowed to disperse throughout the internal volume of the oil separator. (4) Redirection: This technique is associated with increasing the separation efficiency of oil droplets (heavy molecules) present in steam (light small molecules). While the steam is directed towards the outlet of the separator, the oil droplets maintain their original trajectory due to their mass and initial velocity.

[0206] Coalescence can be accomplished using a metal screen or a coalescing cartridge. Centrifugation can be carried out using turbulators, spiral systems or special separation configurations (cyclones).

[0207] An oil separator can include several of the above technologies.

[0208] Among the oil separators useful in the present invention, mention may be made by way of example of Carly's TURBOI, Danfoss's OUB, Emerson's OS, Castel's 5520 and 5540 series, Temprite separators, AC&R separators, Bitzer's OAS for screw compressors.

[0209] The vapor compression circuit may be provided with an oil cooling system and, if necessary, an oil pump and / or an oil supply system between the oil separator and the compressor inlet.

[0210] An oil pump can be used to make up for pressure losses and / or to allow the oil to reach a pressure higher than the compressor discharge pressure. An oil cooling system can be used to cool the oil from the compressor and oil separator.

[0211] flammable The preferred refrigerant fluids F of the present invention have the advantage that they have a flame propagation velocity of less than 10 cm / s, preferably less than 7 cm / s, or even less than 3 cm / s, according to the measurement method developed by Jabbour T-2004. Some compositions are non-flammable.

[0212] This experiment uses the vertical glass tube method (two tubes, 150 cm long, 40 cm diameter). Using two glass tubes allows two tests with the same concentration to be performed simultaneously. Tungsten electrodes are placed in the glass tubes. The electrodes are placed 6.35 mm (1 / 4 in) from the bottom of each tube and connected to a 15 kV, 30 mmA generator.

[0213] This method was developed in the thesis of T. Jabbour's paper "Flammability Classification of Refrigerants Based on the Fundamental Flame Speed", edited by Denis Clodic, Paris, 2004.

[0214] For example, the flame propagation velocity for an HFO-1234yf / R134a / R152a (78.9 / 7.0 / 14.1% by mass) composition is 4.75 cm / s, while for an HFO-1234yf / R134a / R152a (74.2 / 7.7 / 18.1% by mass) composition it is 6 cm / s.

[0215] All of the above embodiments can be combined with each other, i.e., each preferred refrigerant composition can be combined with each of the preferred polyol esters (Ester A, B, C, or D) in different proportions than those described above. Different preferred compositions can be used in different applications described above. [Brief explanation of the drawings]

[0216] [Figure 1] Diagram of temperature (°C, horizontal axis) and pressure (bar, vertical axis) obtained for an R134a / Triton SE55 oil mixture under the following operating conditions. 0% oil corresponds to 100% R134a, while 70% oil corresponds to a mixture containing 30% R134a. The diagram shows that, at constant pressure, the refrigerant concentration in the oil decreases as the temperature Ts of the mixture increases. [Example]

[0217] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0218] POE Triton SE55 Oil, Supplier: FUCHS The oil is collected at the bottom of the oil separator integrated with the screw compressor. In this example, the amount of refrigerant trapped in the oil separator is analyzed. The refrigerant / oil mixture in the oil separator has a temperature TS (which is also the temperature of the refrigerant at the outlet of the compressor), and the pressure in the oil separator is the vapor saturation pressure of the refrigerant at the condenser inlet (P COND ) is equal to the condensation temperature (T cond ) is the temperature at which the corresponding pressure P COND This is the saturation temperature of the refrigerant alone. In general, analysis of a typical refrigerant / oil diagram (Figure 1 shows an example for R134a) shows that the COND ), the temperature of the mixture (oil / refrigerant) (Ts) is cond ) indicates that the concentration of refrigerant in the oil decreases when the temperature increases above the saturation temperature at Ts and T cond The difference between these values ​​represents the superheat at the compressor outlet. Temperature T in the oil separator cond , pressure P COND and temperature Ts are defined according to the operating needs of the system. The percentage of oil in the refrigerant is determined by the pressure P COND and the corresponding refrigerant / oil diagram at temperature Ts. This method allows for indirect comparison of refrigerants by observing the superheat at the compressor outlet.

[0219] Consider an air conditioning system operating in heating (heat pump) mode under the following conditions: Condensing temperature T cond =70℃, Evaporation temperature: 0℃ Evaporator superheat: 0℃ Cooling: 0℃ Compressor efficiency: 75% Reference case: R134a and POE Triton SE5

[0220] From the diagram in Figure 1, the temperature in the separator (TS) is 87°C, the superheat at the compressor outlet at a pressure of 21 absolute bar is 17°C, and the oil percentage is 75% by mass (25% by weight of R134a in oil). In the case of the HFO-1234yf / POE oil Triton SE55 mixture, under the same operating conditions as above, the pressure in the condenser is about 20.5 bar absolute and the superheat at the compressor outlet is about 4.8°C. The saturated pressure of HFO-1234yf is very close to that of R134a, but the superheat is low. Therefore, the concentration of refrigerant in the liquid phase of the oil separator is 30% by mass or more, or even 35% by mass or more.

[0221] As a result, for the same oil / refrigerant fluid flow rate, an increase in the ratio of refrigerant to lubricating oil in the oil separator leads to a decrease in the amount of lubricating oil circulating through the compressor and a decrease in the viscosity of the oil / refrigerant. Therefore, directly replacing R134a over HFO-1234yf will damage the compressor (poor lubrication and low viscosity issues) and reduce performance.

[0222] The table below shows the superheat values ​​at compressor output versus condensing temperature under the same operating conditions as above for different mixtures of R134a and HFO-1234yf.

[0223] Ratio A corresponds to the ratio: TIFF0007752469000019.tif1599

[0224] TIFF0007752469000020.tif191159

[0225] TIFF0007752469000021.tif142159

[0226] The mixture of the present invention has the advantageous advantage that the compressor superheat as defined above is higher than that of HFO-1234yf alone, and is at least 50%, preferably at least 80%, higher than that of HFO1234yf.

[0227] Therefore, the mixture of the present invention can reduce (and / or prevent) the amount of refrigerant trapped in the lubricant oil compared to HFO-1234yf alone, allowing for an increase in the amount of refrigerant circulating in the system and advantageously improving the efficiency of the equipment. In addition, the mixture of the present invention allows for a larger amount of lubricant oil to be recovered in the oil separator than with HFO-1234yf, providing better lubrication for the compressor.

Claims

1. Use of a composition comprising a polyol ester-based lubricant and a refrigerant fluid F comprising at least one tetrafluoropropene and at least one hydrofluorocarbon in a heat transfer system having a vapor compression circuit, the refrigerant fluid F contains 75.5 to 79.5 wt % of HFO-1234yf, 14 to 16 wt % of HFC-152a, and 6.5 to 10.5 wt % of HFC-134a, based on the total weight of the refrigerant fluid F, the sum of the components being 100 wt %, and the vapor compression circuit has an oil separator; 10. The use characterized by:

2. 2. Use according to claim 1, wherein the refrigerant fluid F comprises 77.5% by weight (±0.2%) of HFO-1234yf, 14% by weight (±0.2%) of HFC-152a and 8.5% by weight (±0.2%) of HFC-134a, based on the total weight of the refrigerant fluid F, said composition being an azeotrope having a boiling temperature of from -40.00°C to 70.00°C at a pressure of from 0.5 to 21.0 bar absolute (±0.5%).

3. 3. The use according to claim 2, wherein the composition is an azeotrope having a boiling temperature of 26.97°C (±0.50°C) at a pressure of 7.3 bar absolute (±0.5%).

4. Use according to any one of claims 1 to 3 in mobile or stationary heat pumps, air conditioning, refrigeration, freezing, cogeneration and heat engines.

5. Use according to any one of claims 1 to 3 in a method for generating electricity using a heat engine.

6. Use according to any one of claims 1 to 3 in a method for heating or cooling a fluid or an article by means of a vapor compression circuit containing the heat transfer composition.

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