CN1177371A - Refrigeration working fluid compositions for use in recompression type cooling system - Google Patents

Abstract

A refrigeration working fluid composition which is miscible or partially miscible at a temperature of less than 120°C and immiscible at a temperature of at least about 120°C to 180°C, said refrigeration working fluid comprising: (i) Based on the working fluid composition, about 65% to 95% (by weight) of a refrigerant comprising pentafluoroethane, 1,1,1-trifluoroethane and 1,1, A blend of 1,2-tetrafluoroethane, wherein said tetrafluoroethane is present in an amount of about 0.5% to 10% by weight based on the total weight of the refrigerant, and (ii) with said working fluid Based on the total weight of the composition, about 5%-35% (weight) of a polyol ester lubricant.

Description

Refrigerated working fluid compositions for use in recompression-type cooling systems

This application is a continuation-in-part of US Patent Application Serial No. 08/340,961. This invention relates to refrigerated working fluid compositions designed for efficient operation of recompression type cooling systems. In particular, the present invention relates to refrigeration working fluid compositions, including fluorocarbon (HFC) refrigerant blends and certain polyol ester lubricants, which lubricants have suitable °C) and immiscible with the refrigerant at high temperatures (eg, about 120°C to 180°C or higher), thereby exhibiting reversible miscibility.

Background of the Invention

Mechanical vapor recompression type refrigeration systems including refrigerators, freezers, heat pumps, air conditioning systems and the like are well known. In this type of equipment, a refrigerant of the appropriate boiling point evaporates at low pressure, absorbing heat from the surrounding area. The resulting vapor is then compressed and passed to a condenser where it condenses and gives off heat to the second zone. The condensate is then returned to the evaporator via the expansion valve, thus completing the cycle.

It is now recognized that currently used chlorine-containing refrigerants such as dichlorodifluoromethane will be replaced by chlorine-free refrigerant fluids because of the deleterious impact of chlorinated materials on the ozone layer of the atmosphere. Tetrafluoroethane isomers, especially "refrigerant 134a" which is 1,1,1,2-tetrafluoroethane, are now recognized as desirable fluids for use in refrigeration systems.

Refrigerant working fluids require a lubricant that is compatible and miscible with the refrigerant so that the moving parts of the system are properly lubricated. Currently, such lubricants consist of hydrocarbon mineral oils that are miscible with chlorinated refrigerant fluids and provide effective lubrication.

The use of chlorine-free HFC (hydrofluorocarbon) refrigerants requires new lubricants because mineral oils are not compatible with these materials. This need is well recognized in the art and there are numerous recent publications and patents disclosing various types of synthetic lubricants which are said to be compatible with tetrafluoroethane refrigerant fluids. Esters of polyols are particularly emphasized for use with tetrafluoroethane refrigerants, especially refrigerant R134a.

US Patent 5,021,179, issued June 4, 1991 to Zehler et al. discloses esters of polyols in which the acyl groups have at least 22% of (a) branched acyl groups or (b) acyl groups containing no more than 6 carbon atoms. This patent also shows that the percentage of unbranched acyl groups containing 8 or more carbon atoms and the percentage of branched acyl groups having more than 6 carbon atoms in the ester has a certain ratio and the ratio is not greater than 1.56. In addition the patent requires at least 9 carbon atoms and no more than 81 percent branched or unbranched acyl groups.

PCT application WO90/12849 published November 1, 1990 by Jalley et al. discloses generally liquid compositions containing a major amount of a hydrocarbon containing at least one fluorine atom and one or two carbon atoms and a minor amount of at least one Soluble organic lubricants comprising esters of at least one carboxylic acid of polyols containing at least 2 hydroxyl groups and having the general formula R[OC(O)R'] _n where R is a hydrocarbyl group, each R' is independently hydrogen, straight chain lower hydrocarbyl, branched chain hydrocarbyl or straight chain hydrocarbyl containing 8 to about 22 carbon atoms, with the proviso that at least one R' group is hydrogen, lower straight chain hydrocarbyl or branched chain hydrocarbyl or A carboxylic acid-containing or carboxylate-containing hydrocarbyl group, and n is at least 2.

British Patent 2,216,541, issued to Imperial Chemical Industries on October 23, 1991 and published on October 11, 1989, discloses the use of any ester with a molecular weight of 250 or greater that is suitable for use with Refrigerant 134a (R-134a) Lubricants compatible with some of the refrigerant fluids involved. The patent exemplifies adipate, pyromellitate and benzoate.

European Published Patent Application 440069 of Kao Corporation, published on August 7, 1991, discloses the preparation of fluorinated ethane and the reaction of fatty polyalcohols and linear or branched chain alcohols with fatty polyacids having 2 to 10 carbon atoms. Refrigerant working fluid composed of esters.

European Published Patent Application 415778, Kao Corporation, published March 6, 1991, discloses refrigeration working fluid compositions containing hydrogenated fluoroethanes and esters derived from fatty polyols, saturated fatty dibasic acids, and saturated fatty monobasic acids compound.

European Application 406479, Kyodo Oil Technical Research Center Co., Ltd., published January 9, 1991, discloses lubricants which are said to be compatible with R134a. Suitable lubricants are: esters of neopentyl glycol and linear or branched monobasic fatty acids having 3 to 18 carbon atoms; esters of pentaerythritol, dipentaerythritol and tripentaerythritol with linear or branched C ₂ -C ₁₈ monobasic fatty acids Esters; trihydric polyols of the formula RC(CH ₂ OH) ₃ wherein R is C ₁ -C ₃ alkyl with linear or branched monobasic fatty acids having 2 to 18 carbon atoms and at least 25 mol% of the whole fatty acid An ester of a polybasic acid having 4-36 carbon atoms.

European Published Application 435253 of Nippon Oil Co., Ltd, published on July 3, 1991, discloses a large number of esters that are said to be compatible with R134a, these esters are defined as having a specific structure and are mono-, di- or tripentaerythritol and other polyhydric Alcohols such as trimethylolethane, trimethylolpropane, trimethylolbutane or dimers or trimers thereof with monobasic acids having 2 to 15 carbon atoms and monobasic acids having 2 to 10 carbon atoms Esters of dibasic acids. These esters are said to have a molecular weight of about 200-3000.

European Published Application 430657, Ashai Denka Kogyo Kabushiki, published June 5, 1991, discloses R134a compatible lubricants which are neopentyl glycol esters of fatty acids having 2 to 6 carbon atoms. In that application it is said that if the amount of C ₂ -C ₆ acids is less than 20 mol % so that the average number of carbon atoms of the fatty acid is 6 or less per hydroxyl group of neoglutaric acid, then 7 or 7 Acids with more than 2 carbon atoms will cause incompatibility. Suitable neopentyl glycols include mono, di and tripentaerythritol, trimethylolpropane and trimethylolethane. Polyols must have at least 3 OH.

In the operation of a typical refrigeration system, the working fluid composition, which includes a mixture of refrigerant and lubricant, is conveyed from the compressor (where the temperature is highest and the lubricant is needed) to the condenser (where the temperature drops), and then the working The fluid composition is sent to the evaporator (where the temperature is lowest and no lubricant is required), and the working fluid composition, in evaporated cold form, is returned to the compressor to repeat the cycle.

When the refrigeration working fluid composition of the present invention is located in the evaporator, the ester lubricant and the HFC refrigerant blend are partially or completely homogeneous or miscible, but when the working fluid composition is located in the compressor (where the temperature is high and lubricants are required), ester lubricants are available in very reduced form to lubricate compressors because ester lubricants and refrigerant blends are completely immiscible at high temperatures, ie, about 120°C to 160°C or higher. This is advantageous in separating the ester lubricant from the refrigerant blend in the compressor.

The working fluid compositions of the present invention may also be partially miscible or semi-homogeneous at low temperatures, i.e. the ester and refrigerant blends may exhibit partial miscibility, but such partial miscibility or semi-homogeneity does not prevent combination The object of the present invention can be achieved by the use of such semi-homogeneous compositions in refrigeration equipment and that such semi-homogeneous compositions also exhibit substantially complete immiscibility at higher temperatures, ie, from about 120°C to 180°C or higher.

Therefore, the present inventors found that miscibility/immiscibility can be greatly affected by blending refrigerants. But more importantly the temperature/immiscibility relationship of refrigerant blends such as R125, R143a and R134a or R125 and R143a is opposite to the conventional known temperature/immiscibility relationship of single component refrigerants with polybasic esters .

The inventors have discovered that when the particular refrigerant blend of the present invention is mixed with a polyol ester lubricant, the lubricant becomes immiscible at high temperature to enable refrigeration in the compressor section of a refrigeration system operating at high temperature Separation of lubricant and lubricant so that a portion of the lubricant remains in the compressor section without being circulated through the entire refrigeration system which does not require lubricant.

In contrast, single-component refrigerants such as R134a and R143a are immiscible at low temperatures so that the refrigerant and lubricant are separated in the evaporator section of the refrigeration system operating at low temperatures, so a part of the lubricant remains in the area where no lubricant is needed. The evaporator section thus obstructs the more lubricant-intensive compressor section (see Figures 3 and 4).

Single component refrigerants such as R125 are also undesirable as it is miscible at all temperatures at which the refrigeration system operates, which would cause the lubricant to go sequentially from the evaporator to the compressor to the condenser without using the present invention Refrigerant blends seek the benefits of concentrating and separating immiscible polyol ester lubricants in the compressor section (see Figure 5).

Still other refrigerants such as R32 are undesirable because they are miscible at high temperatures and immiscible at low temperatures (see Figure 6). Such refrigerants, when the working fluid is in the evaporator, cause the lubricant to separate from the working fluid composition, thereby depriving the more lubricating compressor section of lubricant.

European Patent Publication No. 0536940, published April 14, 1993 and assigned to Imperial Chemical Industries PLC, discloses a working fluid comprising a heat transfer fluid comprising at least two selected from the group consisting of hydrofluoro chains and a lubricant. A mixture of alkanes and fluoroalkane compounds. The heat transfer fluid may comprise two, three or more compounds selected from the group consisting of R32, R134, R134a, R125, R125a, R143a and R143. A suitable fluid includes a mixture of R32 and R125.

But as shown in Figure 7, working fluid compositions including R32 and R125 are immiscible at high temperatures, with the exception of compositions of technical grade pentaerythritol, Cekanoic 9 and Cekonic 8, which exhibit out of immiscibility. But if you look at Example E in Figure 1, this lubricant is miscible in the refrigerant blend of the invention at all temperatures and in Example I in Figure 2 this lubricant is miscible at 120-180°C range are immiscible. Thus, it is quite clear that not all refrigerant blends function equally, and that each blend of refrigerants exhibits its own unique miscibility and immiscibility properties. Thus, for one of ordinary skill in the art, the miscibility of a combination of refrigerant blends for a particular polyol ester lubricant based on the teachings of other refrigerant blends such as the blend shown in Figure 7 It's not obvious what the impact is.

Therefore, because European Patent Publication No. 0536940 discloses neither the specific weight percentages (particularly the percentage of R143a) of the unique refrigerant blends cited in the present invention nor the specific lubricants mixed with such blends , and thus cannot be considered with certainty that they will exhibit the same miscibility and immiscibility as the refrigeration working fluid compositions of the present invention. Without extensive research by the present inventors, one cannot readily determine from miscibility data for a single-component refrigerant and a lubricant that blending another refrigerant with the single-component refrigerant will have an effect on the miscibility of the resulting working fluid. what effect.

Leaving the lubricant in the compressor maximizes the effectiveness of the lubricant while leaving it in the evaporator greatly reduces its effectiveness.

Thus, it is completely unexpected that when admixed with selected refrigerants, the lubrication of refrigeration systems can be enhanced without the refrigerants alone making the lubricant immiscible in high temperature environments such as compressors and in low temperature environments. Miscible in environments such as evaporators.

Summary of Invention

According to the present invention, blends of HFC refrigerants and certain polyol esters of monocarboxylic acids for use as refrigeration working fluids exhibiting reversibly miscibility are disclosed which improve the lubrication of refrigeration equipment containing such compositions. Preferred working fluid compositions according to the present invention are as follows:

(a) A refrigeration working fluid composition that is miscible or partially miscible at a temperature of less than 120°C and immiscible at a temperature of at least about 120°C to 180°C, said refrigeration working fluid comprising:

(i) Based on the working fluid composition, from about 65% to 95% by weight of a refrigerant comprising pentafluoroethane, 1,1,1-trifluoroethane and 1 , a blend of 1,1,2-tetrafluoroethane, wherein the amount of tetrafluoroethane is about 0.5% to 10% by weight based on the total weight of the refrigerant, and

(ii) From about 5% to about 35% by weight, based on the total weight of the working fluid composition, of a polyol ester lubricant.

(b) a refrigeration working fluid composition that is miscible or partially miscible below 120°C and immiscible at temperatures of at least about 120°C to 180°C, said refrigeration working fluid comprising :

(i) Based on the working fluid composition, about 65% to 95% (by weight) of a refrigerant comprising a mixture of 1,1,1-trifluoroethane and pentafluoroethane admixture, and

(ii) From about 5% to 35% by weight of a polyol ester lubricant based on the working fluid composition.

Another object of the present invention is a cooling system of the mechanical vapor recompression type comprising an evaporator, a compressor and a condenser in which the refrigeration working fluid compositions (a) and (b) circulate, wherein the refrigeration working fluid composition Miscible or partially miscible in an evaporator at 120°C and immiscible in a compressor at at least about 120-180°C, whereby the polyol ester lubricant is present when the lubricant is most needed The compressor is separated from the refrigerant, and when the refrigeration working fluid is in the evaporator, the polyol ester lubricant is miscible or partially miscible in the refrigerant so that the polyol ester lubricant can be easily Transfer from evaporator to compressor.

A brief description of the attached drawings

Figure 1 shows the reversible miscibility and non-reversible miscibility exhibited by the refrigeration working fluid composition of the present invention comprising 44% R125, 52% R143a and 4% R134a refrigerants and selected polyol ester lubricants Comparison of refrigeration working fluid compositions.

Figure 2 shows the refrigeration working fluid composition of the present invention comprising 55% R143a and 45% R125 refrigerants and selected polyol ester lubricants exhibiting reversible miscibility and refrigeration working fluids not exhibiting reversible miscibility Composition comparison.

Figure 3 shows the relative immiscibility of various polyol ester lubricants in R143a at any temperature;

Figure 4 shows the relative miscibility of various polyol ester lubricants in R134a at any temperature;

Figure 5 shows the relative miscibility of various polyol ester lubricants in R125 at any temperature and the relative immiscibility of other polyol esters in R125 at any temperature;

Figure 6 shows the reversible miscibility of various polyol ester lubricants in R32, where these lubricants are immiscible at low temperature and miscible at high temperature, which is completely contrary to the present invention; and

Figure 7 shows the relative miscibility of various polyol ester lubricants in refrigerant blends of 60% by weight R32 and 40% by weight R125 at any temperature, with the exception of the use of TPE/CK9/CK8 A working fluid is formed which exhibits immiscibility within a narrow temperature range of about 100-130°C.

Detailed description of the present invention

The amount of polyol ester is such that effective lubrication is provided, which is generally about 5-35% by weight based on the total weight of the refrigerant working fluid composition. Preferred amounts are 10%, 25% and 35% ester

The refrigeration working fluid composition of the present invention is preferably:

(a) A refrigeration working fluid composition which is a substantially homogeneous or semi-homogeneous one-phase composition at low temperatures but which exhibits immiscibility at a temperature of about 120-180°C, comprising (i) a refrigerant composed of a blend of 44% by weight of R-125, 52% by weight of R-143a and 4% by weight of R-134a and an effective amount of (ii) polyol ester Lubricants which are esters of (1) a), b) or c) trimethylolpropane: a) 3,5,5-trimethylhexanoic acid, b) 67% by weight of n-heptanoic acid with 24 % (weight) of 2-methylhexanoic acid, 7% (weight) of 2-ethylpentanoic acid and 2% (weight) of a mixture of mixed isomers of _C7 alkanoic acids, c) from about 25% (by weight) of 3,4-dimethylpentanoic acid, 51% by weight of 3,4 and 5-methylhexanoic acid, 8% of n-heptanoic acid, 5% of 3-ethylpentanoic acid and the rest as others Mixtures of branched heptanoic acids, or esters of technical grade pentaerythritol of (2) (a) or (b): (a) branched _C7 acids, which are 27% by weight 2-Ethylvaleric acid, 74% by weight of 2-methylvaleric acid and the remainder being mixed _C7 acid isomers or (b) n-valeric acid; or

(b) a refrigerant working fluid having a substantially homogeneous or semi-homogeneous one-phase composition at low temperatures and exhibiting immiscibility at temperatures from 120°C to 180°C comprising (a) A refrigerant consisting of a mixture of 55-50% by weight R-143a and 45-50% by weight R-125 and (b) an effective amount of a polyol ester lubricant which is: (1) Esters of trimethylolpropane of (a), (b) or (c): (a) 2-ethylhexanoic acid, (b) 3,5,5-trimethylhexanoic acid or (c ) consists of about 25% (by weight) 3,4-dimethylpentanoic acid, 51% 3,4 and 5-methylhexanoic acid, 8% n-heptanoic acid, 5% 3-ethylpentanoic acid and the rest are other branches A mixture of branched heptanoic acids consisting of a mixture of heptanoic acids; (2) esters of technical grade pentaerythritol of (a), (b) or (c): (a) about 75% by weight of 3,5,5- Trimethylhexanoic acid and about 25% (weight) of 25% (weight) 3,5-dimethylhexanoic acid, 19% (weight) 4,5-dimethylhexanoic acid, 17% 3,4-di Methylhexanoic acid, 11% 5-methylheptanoic acid, 5% by weight 4-methylheptanoic acid and the remainder a mixture of branched chain _C8 carboxylic acids consisting of methylheptanoic acid and dimethylhexanoic acid, (b) n-valeric acid, or (c) composed of about 25% 3,4-dimethylpentanoic acid, 51% 3,4 and 5-methylhexanoic acid, 8% n-heptanoic acid, 5% 3-ethyl A mixture of heptanoic acids consisting of valeric acid and the remainder being a mixture of other branched heptanoic acids.

As used herein, R125 refers to pentafluoroethane, R143a refers to 1,1,1-trifluoroethane and R134a refers to 1,1,1,2-tetrafluoroethane.

Miscibility and immiscibility are determined in the following manner. A weighed amount of ester lubricant was poured into a valved glass tube with an internal diameter of 12 mm. This tube is connected to an R-143a refrigerant charging unit where the air is evacuated and a volume of refrigerant is condensed into the glass tube until the desired refrigerant gas pressure drop is achieved. The composition of the lubricant/refrigerant mixture is calculated by measuring tube weight, tube plus lubricant weight, and tube plus lubricant plus refrigerant weight. Lubricant/refrigerant containing tubes Miscibility was observed at room temperature, in high temperature visible baths (temperature thermostated up to 180°C) and in low temperature visible baths (temperature thermostated down to -80°C). A mixture is miscible if a clear layer is observed for a given temperature. If two separate layers are observed the mixture is immiscible. Partial miscibility is a state between miscible and immiscible.

In the data included in the examples, miscibility temperature refers to the lowest temperature observed for a given composition. The highest value for these temperatures is the miscibility value for the working fluid composition with the ester lubricant.

Example

The present invention is illustrated by Figures 1 and 2, which illustrate the reversible miscibility exhibited by the compositions of the present invention, which show three compositional ranges for each ester, namely 10%, 25% and 35% Composite of data obtained for % by weight ester. All percentages are by weight and temperatures are in degrees Celsius.

An interesting phenomenon arises from these examples. Rather than being immiscible in the low temperature range as is often seen in single components such as R143a, it now tends to be immiscible in the higher temperature range, which is particularly desirable for cooling systems. The following examples generate various working fluids that exhibit miscibility at low temperatures and immiscibility at high temperatures. Low temperature miscibility means that the lubricant will not separate out in the coldest part of the cooling system, that is, the part of the cooling system where lubricant accumulation is detrimental to performance. Likewise, high temperature immiscibility means that the lubricant/refrigerant will separate in high temperature areas of the cooling system such as compressors, precisely where the lubricant/refrigerant separation is most needed.

Figures 1 and 2 also show that increased miscibility can be accomplished by mixing refrigerants, as well as by mixing lubricants. R143, which is incompatible with polyol esters, is almost eliminated when it is mixed with R125, even if R125 is a minor component (ie, less than 50%).

In Figure 1, the compositions of the invention, Examples B, C and D, contain the following esters:

B: TMP/CK9-trimethylolpropane ester of 3,5,5-trimethylhexanoic acid (“Cekanoic 9 acid”)

C: TMP/1770-acid mixture i.e. 67% n-heptanoic acid, 24% 2-methylhexanoic acid, 7% 2-ethylpentanoic acid and 2% trimethylolpropane ester of mixed isomers of _C7 acids .

D: TPE/CK7 - trimethylolpropane ester of mixed heptanoic acid ("Cekanoic 7 acid"). Mixed heptanoic acid is a mixture of 23% 2-ethylpentanoic acid, 74% 2-methylhexanoic acid and the rest other _C7 acid isomers.

Comparative compositions A and E contained a refrigerant blend consisting of 44% R125, 52% R143a and 4% R134a mixed with the following esters.

A: Neopentyl glycol ester of 3,5,5-trimethylhexanoic acid.

E: technical grade pentaerythritol ester of a mixture of 85% by weight of (a) and 15% by weight of (b): (a) 3,5,5-trimethylhexanoic acid and (b) isooctanoic acid, which is 26% (weight) of 3,5-dimethyl-, 19% 4,5-dimethyl-, 17% 3,4-dimethylhexanoic acid, 11% 5-methylheptanoic acid, 5% 4 -Methylheptanoic acid and the rest are mixed methylheptanoic and dimethylhexanoic acids.

In Figure 2, the compositions of the invention are compositions F, G and I containing these esters:

F: Trimethylolpropane ester of 2-ethylhexanoic acid.

G: is the same ester as used in composition B.

I: is the same ester as in composition E, except here 75% by weight of 3,5,5-trimethylhexanoic acid and 25% of the same mixture of isooctanoic acids are used.

Comparative Composition H contained a refrigerant blend of 55% R143a and 45% R125 mixed with the following esters:

H: Trimethylolpropane ester of TMP/1770 - acid mixture, acid mixture is a mixture of 67% n-heptanoic acid, 24% 2-methylhexanoic acid, 7% 2-ethylheptanoic acid and 2% _C7 acid isomer.

All esters were evaluated at concentration values of 10%, 25% and 35% by weight based on the total weight of the refrigeration working fluid composition.

The following additional compositions were evaluated at compositional ranges of 10%, 25% and 35% by weight ester and obtained similar results:

Composition J: heptanoic acid mixture (25% 3,4-dimethylpentanoic acid, 51% 3,4 and 5-methylhexanoic acid, 8% n-heptanoic acid, 5% 3-ethylpentanoic acid and the balance mixture of other branched heptanoic acids) was mixed with a blend of 44% R-125, 52% R143a and 4% R-134a and was found to be miscible from -50°C to +58°C while It is immiscible at high temperature.

Composition K: An ester of technical grade pentaerythritol of n-heptanoic acid was evaluated with the same refrigerant blend as ester J and was found to be miscible at -50°C to +63°C and immiscible at elevated temperatures.

Composition L: The same ester used in Composition J was mixed with a blend of 50% by weight 143a and 50% by weight R-125 and was found to be miscible from -50°C to +55°C and immiscible at elevated temperatures.

Composition M: The same ester used in composition K was mixed with the same refrigerant blend in composition L and was found to be miscible at -50°C and +61°C, but immiscible at elevated temperatures.

Composition N: A technical grade pentaerythritol ester of the acid mixture of Composition J mixed with the same refrigerant blend of Composition L was found to be miscible at -50°C and +32°C and immiscible at elevated temperatures of.

Claims (12)

1. refrigeration working fluid compositions, it is miscible during less than 120 ℃ or part is miscible and be at least about 120～180 ℃ for immiscible in temperature in temperature, described refrigeration working fluid comprises:

(i) be base with described working fluid composition, a kind of refrigeration agent of about 65% to 95% (weight), described refrigeration agent comprises pentafluoride ethane, 1,1,1-Halothane and 1,1,1, a kind of adulterant of 2-Tetrafluoroethane, the amount of wherein said Tetrafluoroethane based on the gross weight of refrigeration agent be about 0.5%～10% (weight) and

Be base (ii) with described working fluid composition gross weight, a kind of polyol ester lubricant of about 5%-35% (weight).

2. according to the composition of claim 1, wherein said refrigeration agent comprises the pentafluoride ethane of a kind of 44% (weight), 52% (weight) 1,1,1,1,1 of 1-Halothane and 4% (weight), 2-Tetrafluoroethane.

3. according to the composition of claim 1, wherein said polyol ester lubricant is selected from:

(1) a kind of trishydroxymethyl and be selected from the following at least a acid or the esterification reaction product of acid mixture:

(a) 3,5,5 Trimethylhexanoic acid,

(b) the positive enanthic acid of 67% (weight), the 2 methyl caproic acid of 24% (weight), the C of the 2-ethyl valeric acid and 2% (weight) of 7% (weight) ₇The mixture of the mixed isomers of paraffinic acid and

(c) a kind of mixture of enanthic acid class, by about 25% (weight) 3,4-dimethyl caproic acid, 51% (weight) 3-, the positive enanthic acid of 4-and 5-methylhexanoic acid and 8% (weight), 5% (weight) 3-ethyl valeric acid and all the other be the mixture composition of the enanthic acid of other branching; With

(2) esterification reaction product of technical grade pentaerythritol ester and the mixture that is selected from following at least a acid or acid

(a) C of branching ₇Acid, it is the 2-ethyl valeric acid of 27% (weight), the 2 methyl valeric acid of 74% (weight) and all the other are blended C ₇The mixture that the isomer of acid is formed and

(b) positive valeric acid.

4. refrigeration working fluid compositions, it when being lower than 120 ℃, be miscible or part miscible, under at least about 120 ℃～180 ℃, be immiscible, described refrigeration working fluid comprises:

(i) be base with described working fluid composition, it is a kind of 1,1 that a kind of refrigeration agent of about 65～95% (weight), described refrigeration agent comprise, the adulterant of 1-Halothane and pentafluoride ethane and

Be base (ii) with described working fluid composition, the polyol ester lubricant of about 5%～35% (weight).

5. according to the composition of claim 4, wherein said refrigeration agent comprise 50～55% (weight) 1,1, a kind of adulterant of the pentafluoride ethane of 1-Halothane and 45～50% (weight).

6. according to the composition of claim 4, wherein said polyol ester lubricant is selected from:

(i) TriMethylolPropane(TMP) and be selected from the following at least a acid or the esterification reaction product of acid mixture:

(a) 2 ethyl hexanoic acid,

(b) 3,5,5 Trimethylhexanoic acid and

(c) mixture of the enanthic acid class of branching, comprise 25% (weight) 3,4-dimethyl valeric acid, 3,4 and the 5-methylhexanoic acid of 51% (weight), the positive enanthic acid of 8% (weight), the 3-ethyl valeric acid of 5% (weight) and all the other are the mixture of other branching enanthic acid; With

(2) technical grade pentaerythritol ester and be selected from following at least a acid or a kind of esterification reaction product of acid mixture:

(a) the side chain C of the 3,5,5 Trimethylhexanoic acid of about 75% (weight) and about 25% (weight) ₈The mixture of mixture of carboxylic acids, C ₈Mixture of carboxylic acids is by 3 of 25% (weight), 5-dimethyl caproic acid, 19% (weight) 4,5-dimethyl caproic acid, 17% (weight) 3,4-dimethyl enanthic acid, 11% (weight) 5-methyl enanthic acid, the 4-methyl enanthic acid of 5% (weight) and all the other are that the mixing acid of methyl enanthic acid and dimethyl caproic acid is formed

(b) positive enanthic acid and

(c) a kind of mixture of enanthic acid, comprise about 25% (weight) 3,4-dimethyl valeric acid, 3,4 and the 5-methylhexanoic acid of 51% (weight), the positive enanthic acid of 8% (weight), the 3-ethyl valeric acid of 5% (weight) and all the other are the mixture of other branching enanthic acid.

7. mechanical vapour recompression type cooling system, comprise vaporizer, compressor and condenser, wherein said cooling system comprises a round-robin refrigeration working fluid compositions therein, described refrigeration working fluid compositions is miscible during less than 120 ℃ or part is miscible and be at least about 120～180 ℃ for immiscible in temperature in temperature, and described refrigeration working fluid comprises:

(i) be base with described working fluid composition, a kind of refrigeration agent of about 65% to 95% (weight), described refrigeration agent comprises pentafluoride ethane, 1,1,1-Halothane and 1,1,1, a kind of adulterant of 2-Tetrafluoroethane, the amount of wherein said Tetrafluoroethane based on the gross weight of refrigeration agent be about 0.5%～10% (weight) and

Be base (ii) with described working fluid composition gross weight, a kind of polyol ester lubricant of about 5%-35% (weight), whereby when needing most lubricant described polyol ester lubricant in described compressor, from described refrigeration agent, separate and when described refrigeration working fluid mixture is in described vaporizer described polyol ester lubricant in described refrigeration agent, be miscible or part miscible so that described polyol ester lubricant can be transferred to described compressor from described vaporizer at an easy rate.

8. according to the refrigeration system of claim 7, wherein said refrigeration agent comprises the pentafluoride ethane of a kind of 44% (weight), 52% (weight) 1,1,1,1,1 of 1-Halothane and 4% (weight), 2-Tetrafluoroethane.

9. according to the refrigeration system of claim 7, wherein said polyol ester lubricant is selected from:

(1) a kind of trishydroxymethyl and be selected from the following at least a acid or the esterification reaction product of acid mixture:

(a) 3,5,5 Trimethylhexanoic acid,

(b) the positive enanthic acid of 67% (weight), the 2 methyl caproic acid of 24% (weight), the C of the 2-ethyl valeric acid and 2% (weight) of 7% (weight) ₇The mixture of the mixed isomers of paraffinic acid and

(c) a kind of mixture of enanthic acid class, by about 25% (weight) 3,4-dimethyl caproic acid, 51% (weight) 3-, the positive enanthic acid of 4-and 5-methylhexanoic acid and 8% (weight), 5% (weight) 3-ethyl valeric acid and all the other be the mixture composition of the enanthic acid of other branching; With

(2) esterification reaction product of technical grade pentaerythritol ester and the mixture that is selected from following at least a acid or acid

(a) C of branching ₇Acid, it is the 2-ethyl valeric acid of 27% (weight), the 2 methyl valeric acid of 74% (weight) and all the other are blended C ₇The mixture that the isomer of acid is formed and

(b) positive valeric acid.

10. mechanical vapour recompression type cooling system, comprise vaporizer, compressor and condenser, wherein said cooling system comprises a round-robin refrigeration working fluid compositions therein, described refrigeration working fluid compositions when being lower than 120 ℃, be miscible or part miscible, under at least about 120 ℃～180 ℃ is immiscible, and described refrigeration working fluid comprises:

(i) be base with described working fluid composition, it is a kind of 1,1 that a kind of refrigeration agent of about 65～95% (weight), described refrigeration agent comprise, the adulterant of 1-Halothane and pentafluoride ethane and

Be base (ii) with described working fluid composition, the polyol ester lubricant of about 5%～35% (weight), whereby when needing most lubricant described polyol ester lubricant in described compressor, from described refrigeration agent, separate and when described refrigeration working fluid mixture is in described vaporizer described polyol ester lubricant in described refrigeration agent, be miscible or part miscible so that described polyol ester lubricant can be transferred to described compressor from described vaporizer at an easy rate.

11. according to the cooling system of claim 10, wherein said refrigeration agent comprise 50～55% (weight) 1,1, a kind of adulterant of the pentafluoride ethane of 1-Halothane and 45～50% (weight).

12. according to the cooling system of claim 10, wherein said polyol ester lubricant is selected from:

(i) TriMethylolPropane(TMP) and be selected from the following at least a acid or the esterification reaction product of acid mixture:

(a) 2 ethyl hexanoic acid,

(b) 3,5,5 Trimethylhexanoic acid and

(c) mixture of the enanthic acid class of branching, comprise 25% (weight) 3,4-dimethyl valeric acid, 3,4 and the 5-methylhexanoic acid of 51% (weight), the positive enanthic acid of 8% (weight), the 3-ethyl valeric acid of 5% (weight) and all the other are the mixture of other branching enanthic acid; With

(2) technical grade pentaerythritol ester and be selected from following at least a acid or a kind of esterification reaction product of acid mixture:

(a) the side chain C of the 3,5,5 Trimethylhexanoic acid of about 75% (weight) and about 25% (weight) ₈The mixture of mixture of carboxylic acids, C ₈Mixture of carboxylic acids is by 3 of 25% (weight), 5-dimethyl caproic acid, 19% (weight) 4,5-dimethyl caproic acid, 17% (weight) 3,4-dimethyl enanthic acid, 11% (weight) 5-methyl enanthic acid, the 4-methyl enanthic acid of 5% (weight) and all the other are that the mixing acid of methyl enanthic acid and dimethyl caproic acid is formed

(b) positive enanthic acid and

(c) a kind of mixture of enanthic acid, comprise about 25% (weight) 3,4-dimethyl valeric acid, 3,4 and the 5-methylhexanoic acid of 51% (weight), the positive enanthic acid of 8% (weight), the 3-ethyl valeric acid of 5% (weight) and all the other are the mixture of other branching enanthic acid.

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