KR20070073609A - Centrifugal compression-type refrigerating machine and lubricating oil used for the same - Google Patents

Abstract

A centrifugal compression-type refrigerating machine and lubricating oil used for the same are provided to secure a normal operation of the refrigerating machine even in using 1,1,1,3,3-pentafluoropropane refrigerant by utilizing the lubricating oil containing at least one of polyester and polyether. The centrifugal compression-type refrigerating machine is composed of an evaporator(2), a condenser(1), refrigerant, a centrifugal compressor(3) for compressing the refrigerant sent from the evaporator, a driving source(5) for driving the compressor, lubricating oil, a lubricating oil system(7) for circulating the lubricating oil, and a refrigerant system(14) for circulating the refrigerant. The refrigerant is 1,1,1,3,3-pentafluoropropane. The lubricating oil contains at least one of polyester and polyether as the main component. The lubricating oil has kinematic viscosity of 6~300mm^2/s at 40°C. The main component of the polyester is polyol ester consisting of 2~6 polyhydric alcohol and monohydric fatty acid having 5~12 carbons.

Description

CENTRIFUGAL COMPRESSION-TYPE REFRIGERATING MACHINE AND LUBRICATING OIL USED FOR THE SAME}

1 is a view showing an example of a centrifugal compression refrigerator.

* Description of the symbols for the main parts of the drawings *

1 condenser

2 evaporator

1A, 2A heat pipe

3 centrifugal compressor (turbo compressor)

4 oil tanks

5 drive source

6 oil pump

7 Lube System

8 Moisture Removal Device

9 Moisture Detector

10 oil cooler

11 oil strainer

12 gate valve

13 valve

14 refrigerant system

14A expansion valve

30, 32, 35 oil recovery system

31 ejector

33 Oil Recovery Machine

34 heater

36 Refrigerant Recovery System

51A, 51B, 51C Bearing

[Patent Document 1] Japanese Unexamined Patent Publication No. Hei 6-221696

The present invention relates to a centrifugally compressed refrigerator using 1,1,1,3,3-pentafluoropropane (R245fa) as a refrigerant, and a lubricant used therein.

Background Art Conventionally, centrifugal compression freezers, so-called turbo freezers, have been used for cooling and heating buildings and industrial cold water production plants. As the refrigerant of the centrifugal compressor, a freon such as fluorine and chlorine as constituent elements, for example, R11, which is a chlorofluorocarbon (CFC), has been used internationally. Production and use are regulated and are currently being converted to new hydrogen-containing freon refrigerants that do not contain chlorine, such as, for example, tetrafluoroethane (R134 or R134a).

As a refrigerant, tetrafluoroethane has a ozone layer destruction coefficient (ODP) of 0, but has a high global warming coefficient (GWP), and thus, as a more environmentally friendly refrigerant, 1,1,1,3,3-pentafluoropropane (R245fa) This is drawing attention.

However, when the 1,1,1,3,3-pentafluoropropane refrigerant is used in a centrifugal compression refrigerator, there is a problem that it is not compatible with existing refrigeration oil of mineral oil. The present invention solves these problems, and an object of the present invention is to provide a centrifugal compressor which can operate without any trouble even when 1,1,1,3,3-pentafluoropropane refrigerant is used.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, the present inventors conducted earnest research and, as a result, when using 1,1,1,3,3-pentafluoropropane refrigerant | coolant in a centrifugal compression refrigerator, By using the lubricating oil mentioned above, it was found out that operation of a refrigeration system comparable to that of hydrogen-containing freon refrigerants such as chlorofluorocarbons such as R11 or tetrafluoroethane and the like was possible, and the present invention was conceived.

The centrifugal compressor of the present invention includes an evaporator, a condenser, a refrigerant, a compressor for compressing a refrigerant from the evaporator, a drive source for driving the compressor, a lubricant, a lubricant system through which lubricant is circulated, and a refrigerant system through which the refrigerant circulates. In the compression type refrigerator, the refrigerant is 1,1,1,3,3-pentafluoropropane, the compressor is a centrifugal compressor, and the lubricating oil contains at least one of polyester and polyether as a main component. Moreover, it is preferable that the centrifugal compressor of this invention is equipped with the oil return system which returns the lubricating oil mixed in the refrigerant system to a lubricating oil system. Moreover, the said polyester is a compound containing a some ester bond, and typically polyol ester, diester, and complex ester are contained. Polyol ester is ester synthesize | combined using an acid and a polyhydric alcohol as a raw material, and monovalent acid is used normally. Diester is ester synthesize | combined using alcohol and a polyvalent acid as a raw material, and monohydric alcohol is used normally. Complex ester is ester synthesize | combined using polyhydric acid and polyhydric alcohol as a raw material, and a monovalent acid is contained in a raw material normally.

The lubricating oil used in the centrifugal compression refrigerator according to the present invention is a centrifugal compressor for compressing a refrigerant consisting of an evaporator, a condenser, 1,1,1,3,3-pentafluoropropane, a refrigerant from an evaporator, and the centrifugal compressor. A lubricating oil for use in a centrifugal compressor having a driving source to be driven, a lubricating oil, a lubricating oil system in which lubricating oil circulates, and a refrigerant system circulating in refrigerant, comprising at least one of polyester and polyether as a main component.

It is preferable that the above-mentioned lubricating oil has as a main component the polyol ester which consists of the polyhydric alcohol of 6-300 mm <2> / s in polyester at 40 degreeC, and the polyhydric alcohol whose polyester is 2-6 hexavalent, and the C5-12 monovalent fatty acid. . Moreover, the above-mentioned lubricating oil is the complex whose kinematic viscosity in 40 degreeC is 25-300 mm <2> / s, the polyhydric alcohol whose polyester is a 2-6 hexavalent monohydric acid, a C3-C18 monovalent fatty acid, and a C4-C14 polybasic acid. It is also preferable to have ester as a main component. In addition, it is preferable that the mass ratio of the lubricating oil and the coolant described above is 90:10 to 10:90.

To practice the invention  Best form for

[Centrifugal Compressor]

An example of a centrifugal compression refrigerator is shown in FIG. The centrifugal compressor is composed of a condenser 1, an evaporator 2, a compressor (turbo compressor) 3 of a centrifugal compression type, and a drive source 5 for driving the compressor 3. The condenser 1 has a heat transfer tube 1A for introducing coolant from the outside to cool the high temperature and high pressure refrigerant, and the evaporator 2 has a heat transfer tube 2A for taking out cold water to the outside. The condenser 1, the evaporator 2, and the compressor 3 are connected by the refrigerant system 14, and an expansion valve 14A is interposed between the condenser 1 and the evaporator 2.

The lower part of the compressor 3 has an oil tank 4 for storing lubricating oil, and an oil pump 6 for circulating lubricating oil is provided in the oil tank 4. The lubricating oil system 7 is formed between the oil pump 6, the compressor 3, and the driving source 5 to circulate the lubricating oil to the respective bearing portions 51A, 51B, 51C. The lubricating oil system 7 is provided with a water detector 9 and an oil cooler 10.

The lubricating oil system 7 is provided with an oil recovery function. An ejector 31 is interposed in the first oil recovery system 30 through which the lubricating oil circulates, and a separator valve 12, a water removing device 8, an oil strainer 11, and a valve are disposed on the discharge side of the ejector 31. (13) is interposed and is returned to the oil tank (4). Below the refrigerant liquid surface of the evaporator 2, the vicinity of the refrigerant liquid surface and the negative pressure generating portion of the ejector 31 are connected to the second oil recovery systems 32 and 35 via the oil recovery machine 33.

The heater 34 is for heating the refrigerant liquid in the oil recoverer 33. The second oil recovery system 35 is installed at the bottom of the oil recovery unit 33, and a refrigerant recovery system 36 for recovering the refrigerant is provided at the top of the oil recovery unit 33. 36 is connected to the refrigerant system 14 between the evaporator 2 and the compressor 3.

Next, the effect | action of the centrifugal compression refrigerator of the said structure is demonstrated. The high temperature and high pressure refrigerant gas compressed by the compressor (3) is introduced into the condenser (1), where it is cooled by the cooling water flowing through the heat transfer pipe (1A) and liquefied to become a liquid refrigerant. When the low temperature and high pressure liquid refrigerant leaving the condenser 1 passes through the expansion valve 14A, the temperature is further lowered to become a low temperature low pressure liquid refrigerant and accumulated in the evaporator 2. Here, for example, the cold water that has exchanged heat with the air by the external air control load and has returned after the temperature rises exchanges with the liquid refrigerant by the heat transfer pipe 2A, so that the liquid refrigerant evaporates and becomes a refrigerant gas. This refrigerant gas is compressed by the compressor (3) to be a high-temperature, high-pressure refrigerant gas, introduced into the condenser (1), where the cycle of cooling by the cooling water flowing through the heat transfer pipe (1A) and liquefying to become a liquid refrigerant is repeated. do.

In the vicinity of the refrigerant liquid level below the evaporator 2, the lubricating oil fraction leaking out from the compressor 3 is separated from the refrigerant to form a lubricating oil layer on the refrigerant. Lubricating oil is blown in from the lubricating oil layer to the oil returning machine 33 via the oil return system 32. In the oil recovery unit 33, the refrigerant gas from the condenser 1 passes through the piping of the heater 34, and by this heat, the refrigerant mixed in by heating the lubricating oil in the oil recovery unit 33 is vaporized, thereby concentrating the concentration of the lubricating oil. Increase On the other hand, the lubricating oil is sucked up from the oil return device 33 by the negative pressure generated by the ejector 31 from the oil return device 33 and returns to the oil tank 4.

[Refrigerant]

As the refrigerant, a refrigerant mainly containing 1,1,1,3,3-pentafluoropropane (R245fa) is used. The content of 1,1,1,3,3-pentafluoropropane in the refrigerant is preferably at least 50 mass%, particularly at least 90 mass%. As the other refrigerant to be mixed, a refrigerant having an ozone layer destruction coefficient (ODP) of 0 and a hydrogen-containing freon refrigerant are preferable, and tetrafluoroethane (R134 or R134a) is particularly preferable.

Mass ratio of lubricating oil and refrigerant | coolant is 90: 10-10: 10, especially 50: 50-10: 90,

Furthermore, 30: 70-10: 90 are preferable at the thermal efficiency of a system.

[lubricant]

The lubricating oil has at least one of polyester and polyether as a main component, and preferably, at least one of polyol ester, diester, polyether and complex ester. It is preferable to contain 80 mass% or more, especially 90 mass% or more of these compounds in total. As the lubricant base oil, other components that may be contained include mineral oil-based refrigeration oil lubricant oil. Here, in the case where the lubricating oil contains polyol ester, diester or polyether as a main component, in order to operate the refrigeration system properly and to ensure high efficiency, the kinematic viscosity at 40 ° C. is 6 to 300 mm 2 / s, in particular It is preferable from the viewpoint of the thermal efficiency of a system that it is 6-80mm <2> / s, Furthermore, it is 7-70mm <2> / s. Moreover, when lubricating oil has a complex ester as a main component, in order to operate a refrigeration system appropriately and to ensure high efficiency, the kinematic viscosity in 40 degreeC is 25-300mm <2> / s, especially 32-80mm <2> / s Furthermore, it is preferable from the viewpoint of the thermal efficiency of a system that it is 32-70mm <2> / s. As base oils other than these compounds, mineral oil and synthetic oil generally used as lubricating oil base oil can be added as desired.

[Polyol ester]

As the polyol ester, esters of polyols having 3 to 20 diols or hydroxyl groups and fatty acids having 6 to 20 carbon atoms are preferably used. Here, as the diol, specifically, ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-pentane Diol, neopentylglycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol Etc. can be mentioned.

As the polyol having 3 to 20 hydroxyl groups, specifically, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, and di- (Pentaerythritol), tri- (pentaerythritol), glycerin, polyglycerol (2-20 monomers of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol Polyhydric alcohols such as, arabitol, xylitol, mannitol, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalo Sugars such as os, sucrose, raffinose, gentianose, melezitose and the like, and partial ethers thereof, and methylglucoside (glycoside).

Among these, as diol or polyol, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, di- (pentaerythritol) And hindered alcohols such as tri- (pentaerythritol) are preferable. Although the carbon number is not specifically limited in the diol or polyol used, Usually, C1-C24, Preferably C2-C12, Furthermore, C4-C8 is used preferably.

Although the carbon number is not specifically limited in the fatty acid used for a polyol ester, Usually, the C1-C24 thing is used. Among fatty acids having 1 to 24 carbon atoms, those having 3 or more carbon atoms are preferred from the viewpoint of lubricity, more preferably 4 or more carbon atoms, still more preferably 5 or more carbon atoms, and particularly preferably 7 or more carbon atoms. In terms of compatibility with the refrigerant, one having 18 or less carbon atoms is preferable, one having 12 or less carbon atoms is more preferable, and one having 9 or less carbon atoms is still more preferable.

Moreover, although any of linear fatty acid and branched fatty acid may be sufficient as this fatty acid, linear fatty acid is preferable from a lubricity point, and a branched fatty acid is preferable from a hydrolysis stability point. As fatty acids, specifically, pentanic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid , Octadecanoic acid, nonadecaic acid, icosane acid, oleic acid, and the like, and these fatty acids may be any of linear or branched fatty acids, and furthermore, fatty acids (neo acids) in which the α carbon atom is a quaternary carbon atom. It may be. Among these, valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), ferragonic acid (n-nonanoic acid), and ka Fric acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid and 3 , 5,5-trimethylhexanoic acid is preferably used.

In addition, as long as it has two or more ester groups, the polyol ester which concerns on this invention may be partial ester in which some of the hydroxyl groups which polyol has remain without being esterified, or the complete ester in which all the hydroxyl groups were esterified, and also the partial It may be a mixture of an ester and a full ester, but is preferably a full ester. When the residual amount of carboxyl groups is large, undesired phenomena such as the generation and precipitation of metal soap may also occur due to the reaction with the metal used in the refrigerator, and the total acid value is preferably 3 mgKOH / g or less. It is more preferable that it is mgKOH / g or less. In addition, when there is much residual amount of hydroxyl groups, since an undesired phenomenon arises, such as ester clouding at low temperature and blocking the capillary apparatus of a refrigeration cycle, it is preferable to set it as 50 mgKOH / g or less, and 10 It is more preferable that it is mgKOH / g or less.

[Diester]

As diester, ester of a C4-C14 polybasic acid and a C5-C18 alcohol is used preferably. Here, as a polybasic acid, adipic acid, azelaic acid, a sebacic acid, an undecanic acid, a dodecanic acid, a terephthalic acid, etc. are mentioned specifically, and adipic acid, azelaic acid, and sebacic acid are preferable.

Moreover, as alcohol, 2-ethylhexanol, 3,5,5-trimethylhexanol, decyl alcohol, lauryl alcohol, oleyl alcohol, etc. are mentioned specifically, and a monohydric alcohol also has carbon number. It is preferable to have a branch in the hydrocarbon group which is 6-12, especially 8-10. Specifically, 2-ethylhexanol and 3,5,5-trimethylhexanol are preferable.

[Polyether]

Polyether is an organic compound which has a some ether bond, and is represented by following General formula (1) or (2) typically.

[Formula 1]

[Formula 2]

In the formula, R ¹ to R ⁵ each represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and A ¹ to A ³ each represent one or two or more kinds of 5 to 300 alkylene oxide units having 5 to 300 carbon atoms in the polymerization chain. Indicates.

R ¹ to R ⁵ are each preferably hydrogen, a methyl group, an iso-propyl group, an iso-butyl group, or a tert-butyl group, and particularly preferably all are methyl groups. As the alkylene oxide unit, an ethylene oxide unit or a propylene oxide unit is preferable, and the polymerization chain may be a block copolymer chain, a random copolymer chain or an alternating copolymer chain. The number of alkylene oxide units in the polymerization chain is set so that the viscosity of the polyether is within a predetermined range.

As a specific polyether, polyalkylene glycol or its derivative (s), polyvinyl ether, etc. are mentioned, The polyalkylene glycol derivative or polyvinyl ether whose both terminals are an alkyl group is preferable.

[Complex Ester]

As complex ester, ester of the mixed acid of diol or the polyol which has 3-20, especially 2-6, and C3-C18 monovalent fatty acid and C4-C14 polybasic acid is used preferably. Here, as the diol, specifically, ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5-pentane Diol, neopentylglycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol Etc. can be mentioned. As for carbon number of diol, 4-12 are especially preferable.

As the polyol having 3 to 20 hydroxyl groups, specifically, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, and di- (Pentaerythritol), tri- (pentaerythritol), glycerin, polyglycerol (2-20 monomers of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol Polyhydric alcohols such as, arabitol, xylitol, mannitol, xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalo Sugars such as os, sucrose, raffinose, gentianose, melezitose and the like, and partial ethers thereof, and methylglucoside (glycoside).

Among these, as diol or polyol, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, di- (pentaerythritol) And hindered alcohols such as tri- (pentaerythritol) are preferable. As for carbon number of a polyol, 3-15, Especially 5-10 are preferable.

Although the carbon number is not specifically limited in the monovalent fatty acid used for complex ester, Usually, C3-C24, Preferably the thing of 3-18 is used. Among the monovalent fatty acids having 3 to 24 carbon atoms, those having 3 or more carbon atoms are preferable in terms of lubricity, more preferably 4 or more carbon atoms, still more preferably 5 or more carbon atoms, and particularly preferably 7 or more carbon atoms. Further, from the viewpoint of compatibility with the refrigerant, those having 18 or less carbon atoms are preferable, those having 12 or less carbon atoms are more preferable, and those having 9 or less carbon atoms are more preferable.

The monovalent fatty acid may be either a linear fatty acid or a branched fatty acid, but is preferably a linear fatty acid in terms of lubricity and a branched fatty acid in terms of hydrolytic stability. Specific examples of the monovalent fatty acid include pentanic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, and hepta. Decanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, oleic acid, and the like, and these fatty acids may be any of linear fatty acids and branched fatty acids, and furthermore, fatty acids whose alpha carbon atoms are quaternary carbon atoms (neo Acid). Among these, valeric acid (n-pentanoic acid), caproic acid (n-hexanoic acid), enanthic acid (n-heptanoic acid), caprylic acid (n-octanoic acid), ferragonic acid (n-nonanoic acid), and ka Fric acid (n-decanoic acid), oleic acid (cis-9-octadecenoic acid), isopentanoic acid (3-methylphthalic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid and 3 , 5,5-trimethylhexanoic acid is preferably used.

As polybasic acid, C4-C14, especially 6-12 are preferable, and bivalent carboxylic acid is used normally, Specifically, succinic acid, glutaric acid, adipic acid, pimeric acid, subberic acid, azelaic acid, Sebacic acid, undecane diacid, dodecane diacid, and the like, and adipic acid, azelaic acid, and sebacic acid are preferably used. As for the mass ratio of the polybasic acid and monovalent fatty acid which comprise complex ester, 10: 90-90: 10 is especially 50: 50-70: 30.

In addition, as long as it has two or more ester groups, the complex ester which concerns on this invention may be partial ester in which some of the hydroxyl groups which a polyol has remain without being esterified, the complete ester in which all the hydroxyl groups were esterified, and also the partial It may be a mixture of an ester and a full ester, but is preferably a full ester. When the residual amount of carboxyl groups is large, undesirable phenomena such as metal soap and the like are produced by the reaction with the metal used inside the refrigerator, and precipitation occurs, so that the total acid value is preferably 3 mgKOH / g or less, It is more preferable that it is 0.1 mgKOH / g or less. In addition, when there is much residual amount of hydroxyl groups, since undesirable phenomenon arises, such as ester clouding at low temperature and closing the expansion mechanism of a refrigeration cycle, a hydroxyl value is preferable to be 50 mgKOH / g or less, It is more preferable that it is mgKOH / g or less.

[Lubricant Additives]

Various additives conventionally used for refrigerator oil, for example, load-bearing additives, chlorine trapping agents, antioxidants, metal deactivators, antifoaming agents, oil-based agents, anti-wear additives, extreme pressure agents and the like, can be blended into the lubricating oil.

The load-bearing additives include those of organic sulfur compounds such as monosulfides, polysulfides and sulfoxides, phosphate esters such as phosphate monoesters, phosphate diesters and phosphate triesters, and monophosphate Phosphate esters such as esters and phosphite diesters; Thiophosphate esters such as thiophosphate triesters; Fatty acid esters such as polyhydric alcohol esters and acrylic acid esters; Fatty acid esters such as higher alcohols The system etc. are mentioned.

Examples of the chlorine trapping agent include glycidyl ether group-containing compounds, epoxidized fatty acid monoesters, epoxidized fats and oils, epoxycycloalkyl group-containing compounds, and the like. As antioxidant, phenols (2,6-di-tert-butyl phenol, 2,6-di-tert-butyl-p-cresol, 4,4-methylene-bis- (2,6-di-tert-butyl- p-cresol)), aromatic amines (α-naphthylamine, p, p'-di-octyl-di-phenylamine), and the like. As a metal deactivator, a benzotriazole derivative etc. are mentioned. Examples of the antifoaming agent include silicone oil (dimethylfolic acid), polymethacrylate, and the like.

EXAMPLE

Hereinafter, an Example demonstrates this invention concretely.

[Preparation of Disclosure Oil]

The following eleven formulas were used. Test oils a to c are examples of polyol esters, test oil d is an example of diesters, test oil e is an example of polyethers, and test oils f to h are examples of complex esters. As a comparative example, test oils i-k were mentioned. The kinematic viscosity, total acid value, and color of these test oils are shown in Table 1, respectively. In addition, the kinematic viscosity measured JIS K 2283, the total acid value, JIS K 2501, and the color by the ASTM color test method of JIS K 2580.

(Test oil a) Ester of neopentyl glycol and 2-ethylhexanoic acid.

(Process oil b) A mixture of 20 mass% of esters of neopentyl glycol and 2-ethylhexanoic acid, and 80 mass% of esters of pentaerythritol and 2-ethylhexanoic acid.

(Test oil c) Ester of pentaerythritol and the mixed acid of 50 mass% of 2-ethylhexanoic acid, and 50 mass% of 3,5,5-trimethylhexanoic acid.

(Starting oil d) Diester (dioctyl sebacate) of sebacic acid and 2-ethylhexanol.

(Disclosure u _{e) CH 3 -O- (PO)} m (EO) n polyether copolymer structure represented by -CH _3. The molar ratio (m / n) of the oxypropylene group represented by (PO) and the oxyethylene group represented by (EO) is 8/2, and the average molecular weight is about 1000.

(Test oil f) Complex ester of neopentyl glycol and mixed acid (a mixture of 70 mass% of 3,5,5-trimethylhexanoic acid and 30 mass% of adipic acid).

(Test oil g) Complex ester of trimethylolpropane and mixed acid (mixture of 95 mass% of 3,5,5-trimethylhexanoic acid and 5 mass% of adipic acid).

(Test oil h) Complex ester of trimethylolpropane and mixed acid (mixture of 90 mass% of 2-ethylhexanoic acid, and 10 mass% of sebacic acid).

(Published oil i) Refrigerator oil of naphthenic mineral oil (Nihon Sun Oil Co., Ltd. sniso 3GS).

(Official oil j) straight chain alkylbenzene (Matsumura oil production barrel freeze).

(Published oil k) branched alkylbenzene (Shin Nihon Petroleum Atmos).

Kinematic viscosity ㎜ / s (40 ℃) Total acid value mgKOH / g Color (ASTM) Announcement a 7.6 0.01 L0.5 Announcement b 29.5 0.01 L0.5 Announcement c 68.2 0.01 L0.5 Announcement d 11.7 0.01 L0.5 Announcement e 46.0 0.01 L0.5 Announcement f 150.2 0.01 L0.5 Disclosure oil g 68.3 0.01 L0.5 Announcement h 75.2 0.01 L0.5 Announcement i 29.0 0.01 L1.0 Announcement j 26.0 0.01 L0.5 Announcement k 31.5 0.01 L0.5

[Evaluation of disclosure oil]

R245fa was used as the refrigerant to evaluate the two-layer separation temperature and chemical stability of the test oil. The two-layer separation temperature is 10 mass% (oil / R245fa = 1/9) and 20 mass% (oil / R245fa = 2) of oil content according to JIS K 2211 Annex 3 "Compatibility test method with refrigerant" / 8) separation layer temperature was measured. Chemical stability measured the color of the solution after 175 degreeC and 14 days by Annex 2 "The chemical stability test method with a refrigerant" of JISK2211. These results are shown in Table 2.

2 layer separation temperature Chemical stability Fraction 10 mass% Fraction 20 mass% Color of solution Announcement a -40 ℃ or less -40 ℃ or less L1.0 Announcement b -40 ℃ -34 ℃ L1.0 Announcement c -38 ℃ -33 ℃ L1.0 Announcement d -40 ℃ or less -40 ℃ or less L1.0 Announcement e -40 ℃ or less -40 ℃ or less L1.0 Announcement f -40 ℃ or less -40 ℃ or less L1.0 Disclosure oil g -40 ℃ or less -40 ℃ or less L1.0 Announcement h -40 ℃ or less -40 ℃ or less L1.0 Announcement i Insoluble at room temperature Insoluble at room temperature Do not conduct Announcement j Insoluble at room temperature Insoluble at room temperature Do not conduct Announcement k Insoluble at room temperature Insoluble at room temperature Do not conduct

From Table 2, it can be seen that the test oils a to h are chemically stable because they do not phase separate from the refrigerant even at a low temperature, and the color after the chemical stability test does not change.

Industrial availability

In the centrifugal compressor, even when 1,1,1,3,3-pentafluoropropane refrigerant is used, operation can be performed without any problem as in the case of the conventional freon refrigerant.

As a lubricant of a centrifugal compression refrigerator using 1,1,1,3,3-pentafluoropropane (R245fa) as a refrigerant, by using a lubricant mainly composed of at least one of polyester and polyether, Since they do not phase separate at a sufficiently low temperature, are commercially available, and are chemically stable, even when 1,1,1,3,3-pentafluoropropane refrigerants are used, operation can be performed without problems as in the case of conventional freon refrigerants. It becomes possible.

Claims (7)

A compressor comprising: an evaporator, a condenser, a refrigerant, a compressor for compressing the refrigerant from the evaporator, a drive source for driving the compressor, a lubricating oil, a lubricating oil system in which the lubricating oil circulates, and a refrigerant system in which the refrigerant circulates. And a 1,1,3,3-pentafluoropropane, the compressor is a centrifugal compressor, and the lubricating oil has at least one of polyester and polyether as a main component. The method of claim 1, The lubricating oil of Claim 1 which has a kinematic viscosity in 40 degreeC of 6-300 mm <2> / s, and has a polyol ester which consists of a polyhydric alcohol whose polyester is a 2-6 hexavalent monohydric fatty acid, and a C5-12 monovalent fatty acid. Centrifugal compression freezer characterized in that. The method of claim 1, The lubricating oil of Claim 1 is a polyhydric alcohol whose kinematic viscosity in 40 degreeC is 25-300 mm <2> / s, and a polyester is a 2-6 valent polyhydric acid, a C3-C18 monovalent fatty acid, and a C4-C14 polybasic acid complex. A centrifugal compressor having a ester as a main component. The method of claim 1, The mass ratio of the lubricating oil and refrigerant | coolant of Claim 1 is 90: 10-10: 90, The centrifugal compression type refrigerator. A refrigerant consisting of an evaporator, a condenser, 1,1,1,3,3-pentafluoropropane, a centrifugal compressor for compressing the refrigerant from the evaporator, a drive source for driving the centrifugal compressor, a lubricating oil, a lubricating oil system in which the lubricating oil circulates, and A lubricating oil for use in a centrifugal compressor having a refrigerant system in which a refrigerant circulates, the lubricating oil for use in a centrifugal compressor having a main component of at least one of polyester and polyether. The method of claim 5, The lubricating oil according to claim 5 having a polyol ester composed of a polyhydric alcohol having a kinematic viscosity at 40 ° C. of 6 to 300 mm 2 / s and a polyester of 2 to 6 valent monovalent fatty acid having 5 to 12 carbon atoms as a main component. Lubricant oil for use in centrifugal compressors. The method of claim 5, The lubricating oil of Claim 5 has the kinematic viscosity in 40 degreeC 25-300mm <2> / s, and is a complex of the polyhydric alcohol which is 2-6 hexavalent polyester, C3-C18 monovalent fatty acid, and C4-C14 polybasic acid. Lubricating oil used in a centrifugal compressor, characterized in that the ester as a main component.

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