WO2013051271A1

WO2013051271A1 - Refrigeration device

Info

Publication number: WO2013051271A1
Application number: PCT/JP2012/006379
Authority: WO
Inventors: 信吾大八木; 石田　貴規; 佐藤　成広; 健苅野
Original assignee: パナソニック株式会社
Priority date: 2011-10-06
Filing date: 2012-10-04
Publication date: 2013-04-11
Also published as: JP2014240702A

Abstract

A refrigeration device configured so as to be equipped with a refrigerant circulation path in which a refrigerant circulates from a compressor (120) and returns to the compressor (120) via a condenser (121), an expansion mechanism (122), and an evaporator (123), with a single refrigerant composed of a hydrofluoroolefin having a carbon double bond used as the working refrigerant, or a mixed refrigerant for which a hydrofluorocarbon having no double bonds is mixed in a hydrofluoroolefin used as the working refrigerant, and with a kinetic viscosity of 0.1 mm²/s - 100 mm²/s for the refrigerant oil when the compressor (120) is operating. Thus, it is possible to provide a refrigeration device with which the generation of polymer substances can be suppressed by preventing the occurrence of a high-pressure, high-temperature state which is a condition in which polymers are generated, thereby preventing deterioration and damage to mechanisms in the refrigeration device due to polymer substances, and with which reliability and high efficiency are ensured.

Description

Refrigeration system

The present invention relates to a refrigeration system using a hydrofluoroolefin having carbon-carbon double bonds as a refrigerant.

Currently, efforts to prevent global warming on a global scale are popular. On the other hand, refrigerant manufacturers, refrigeration oil manufacturers and air conditioner manufacturers are researching and developing new refrigerants and refrigerant oils for new refrigerants with the aim of further reducing and improving the global warming potential (GWP) while being safe. Is going. Currently, unsaturated fluorohydrocarbon refrigerants such as tetrafluoropropene (HFO 1234yf) and trifluoropropene (HFO 1234ze) are expected to be adopted as new refrigerants aiming at such improvement (see, for example, Patent Document 1).

A compressor and a refrigeration cycle apparatus using a conventional HFC-based refrigerant will be described with reference to FIGS. 4 to 6 (see, for example, Patent Documents 2 and 3).

FIG. 4 is a longitudinal sectional view of a rotary compressor used under the conventional HFC refrigerant described in Patent Document 2. As shown in FIG.
The stator 2 a of the motor 2 is fixed to the upper part of the closed container 1, and the compression mechanism 5 is fixed to the lower part of the closed container 1. The compression mechanism 5 has a shaft 4 driven by the rotor 2 b of the motor 2. A main bearing 7 is fixed to the upper end of the cylinder 6 of the compression mechanism 5 and a sub-bearing 8 is fixed to the lower end by a bolt or the like. The piston 9 is inserted into the eccentric portion 4 a of the shaft 4 in the cylinder 6 to perform eccentric rotation.
Further, R410A (a mixture of HFC32 and HFC125) is enclosed in the closed container 1 as a refrigerant. From the viewpoint of compatibility with the refrigerant, a refrigerator oil 3 having polarity such as polyol ester (POE) or polyvinyl ether (PVE) is stored at the bottom of the closed container 1.

FIG. 5 is a cross-sectional view of a rotary compressor used under the conventional HFC refrigerant described in Patent Document 2. As shown in FIG. A piston 9 is inserted into the inner surface of the cylinder 6 and rotates with the rotation of the shaft 4. The refrigerant is sucked and compressed in the suction chamber 13 and the compression chamber 14 partitioned by the vanes 10.

The operation and action of the rotary compressor configured as described above will be described below.
First, the refrigerant is drawn into the suction chamber 13 from the suction port 12 provided in the cylinder 6. Further, the refrigerant in the compression chamber 14 is compressed along with the leftward rotation (in the direction of the arrow) of the piston 9 and is discharged into the sealed container 1 from the discharge port (not shown) through the discharge notch 15. The refrigerant discharged into the closed container 1 passes through the gap of the motor 2 and is discharged from the discharge pipe 16 in the upper part of the closed container 1. At this time, the mist of the refrigerator oil 3 in the upper part of the closed container 1 also It is discharged.

Next, the basic refrigeration cycle apparatus described in Patent Document 3 will be described with reference to FIG. This refrigeration cycle apparatus is provided with a rotary compressor 20 that sucks and compresses HFC refrigerant and discharges the refrigerant. As shown in FIG. 6, the rotary compressor 20 compresses the low temperature, low pressure refrigerant gas, discharges the high temperature, high pressure refrigerant gas, and sends it to the condenser 21. The HFC refrigerant gas sent to the condenser 21 is discharged to the air as high temperature, high pressure refrigerant liquid while releasing its heat into air, and is sent to the expansion mechanism (for example, an expansion valve or capillary tube) 22. The high temperature, high pressure refrigerant liquid passing through the expansion mechanism 22 becomes a low temperature, low pressure wet vapor by the throttling effect and is sent to the evaporator 23. The refrigerant that has entered the evaporator 23 absorbs heat from the surroundings and evaporates, and the low-temperature, low-pressure refrigerant gas that has left the evaporator 23 is sucked into the rotary compressor 20. Thereafter, the above cycle is repeated.

Unexamined-Japanese-Patent No. 2010-2074 Japanese Patent Application Laid-Open No. 11-236890 JP-A-8-240362

However, unsaturated fluorocarbon refrigerants, which have been studied in recent years, have low GWP values as one of their features, but have unsaturated bonds in their molecules. Therefore, the reactivity is higher and the thermal and chemical stability is poor compared to conventional saturated fluorinated hydrocarbon refrigerants such as HFC410A. Therefore, there is a possibility of reacting with radicals generated in the high temperature portion such as the sliding portion of the compressor.
The hydrofluoroolefin reacted with the radical is decomposed to release hydrogen fluoride. Further, a plurality of hydrofluoroolefins are polymerized to form oligomers, and a viscous liquid or a solid is formed when the polymerization further proceeds. As a result of the verification experiment, a solid product was generated which was presumed to be a polymer of the refrigerant in the air conditioning reliability test. If such a product is generated, there is a high possibility of adverse effects such as biting into a minute gap in the apparatus.

The present invention solves the above-mentioned conventional problems, and optimizes the viscosity of a refrigerator oil in a refrigeration cycle to a viscosity suitable for a working refrigerant in an actual operating condition during compressor operation to generate a polymer. An object of the present invention is to provide a refrigeration system capable of stably operating for a long period of time, suppressing damage in the system and preventing deterioration of the performance of the refrigeration cycle.

In order to solve the above-mentioned conventional problems, the present invention uses a single refrigerant of hydrofluoroolefin having carbon-carbon double bond as a working refrigerant, or mixes hydrofluorocarbon having no double bond with hydrofluoroolefin. The system has a refrigerant circulation path in which the mixed refrigerant is used as the working refrigerant and the working refrigerant is circulated by the compressor, and the kinetic viscosity of the refrigerating machine oil during operation becomes 0.1 mm ² / s or more and 100 mm ² / s or less It contains refrigerant oil. Thereby, generation | occurrence | production of a polymer can be suppressed and the failure | damage of an apparatus and the performance fall of a refrigerating cycle can be prevented.

The refrigeration system of the present invention can maintain refrigeration oil excellent in wear resistance even when using a low GWP refrigerant having a property of easily generating a polymer. By making metal contact unlikely to occur and preventing the occurrence of high pressure and high temperature conditions, which are the generation conditions of the polymer, it is possible to suppress the formation of the polymer and to prevent the breakage of the device and the deterioration of the performance of the refrigeration cycle. This makes it possible to provide a refrigeration system that achieves high efficiency and high reliability.

The cycle diagram of the refrigeration system in the first embodiment of the present invention Longitudinal cross-sectional view of the rotary compressor in the refrigeration system of Embodiment 1 Cross-sectional view of a rotary compressor in the refrigeration system of Embodiment 1 Longitudinal sectional view of a rotary compressor in a conventional frozen bed Cross-sectional view of the same conventional rotary compressor Cycle diagram of the same conventional refrigeration cycle device

103 refrigerator oil 105 compression mechanism unit 106 cylinder 109 piston 110 vane 120 compressor 121 condenser 122 expansion mechanism 123 evaporator

In the first invention, a single refrigerant of hydrofluoroolefin having double bond between carbon and carbon is used as a working refrigerant, or a mixed refrigerant obtained by mixing hydrofluoroolefin with hydrofluorocarbon having no double bond is used as working refrigerant. The compressor has a refrigerant circulation path for circulating a working refrigerant by a compressor, and the compressor is filled with a refrigerator oil having a kinematic viscosity of 0.1 mm ² / s or more and 100 mm ² / s or less during operation. . According to this configuration, the refrigeration oil can be maintained in a state excellent in wear resistance, and the occurrence of high temperature and high pressure conditions at a local sliding point which is a generation factor of the polymer can be suppressed. By preventing clogging of the circulation path by the polymer and achieving the operation stability, it is possible to prevent damage to each device in the refrigeration cycle and performance deterioration of the refrigeration cycle.

A second invention is to contain an acid scavenger in a refrigerator oil in the refrigeration apparatus of the first invention. According to this configuration, it is possible to prevent the deterioration of the refrigeration oil, to further suppress the decomposition of the refrigerant, to suppress the formation of a polymer, and to further improve the reliability of the refrigeration system.

A third aspect of the invention is to contain an anti-wear agent in refrigeration oil, particularly in the refrigeration system of the first or second aspect of the invention. According to this configuration, the generation of the polymer can be suppressed and the wear resistance can be improved by suppressing the occurrence of the high temperature and high pressure state at the sliding portion.

According to a fourth aspect of the invention, in the refrigeration apparatus according to the first to third aspects of the invention, the compression mechanism portion of the compressor has a piston and a vane in a cylinder, and the vane is subjected to nitriding treatment. A steel or a sintered alloy steel subjected to a sintering or quenching treatment is used. According to this configuration, while maintaining the wear resistance of the compression mechanism portion, the decomposition of the refrigerant and the refrigerator oil is suppressed, and the local temperature rise at the sliding portion between the vane and the piston is alleviated. By preventing the occurrence, long-term reliability of the compressor and the refrigeration cycle apparatus using the same can be ensured. In addition, by sintering and quenching the vane, it is possible to obtain a hard structure in which W, Mo, Cr, and V-based carbides are dispersed in a fine martensitic material. Since cast iron is inexpensive, the compressor can be made excellent in mass productivity.

According to a fifth invention, in the refrigeration system of the fourth invention, the sintered alloy steel is a high speed tool steel. According to this configuration, among the sintered alloy steels, the wear resistance can be further improved.

According to a sixth aspect of the invention, in the refrigeration apparatus according to the first to third aspects of the invention, the compression mechanism portion of the compressor has a piston and a vane in a cylinder, and the vane has a ceramic or iron surface treated with a ceramic. It is what used the system base material. According to this configuration, it is possible to suppress the temperature rise due to the sliding friction between the severed tip end of the vane and the piston outer peripheral portion to alleviate the decomposition of the refrigerant, and additionally to maintain the polarity of the sliding portion surface. Since a uniform extreme pressure layer is formed on the sliding surface, the reliability of the sliding surface can be secured.

A seventh aspect of the invention is the refrigerator according to the first to sixth aspects of the invention, wherein the hydrofluoroolefin is mainly composed of a single refrigerant of tetrafluoropropene or trifluoropropene, or tetrafluoropropene or trifluoropropene as a main component, and the earth The working refrigerant is a mixed refrigerant obtained by mixing two or three components so that the global warming potential is 5 or more and 750 or less. According to this configuration, it is possible to provide a highly reliable and highly efficient rotary compressor with a small environmental load.

In an eighth invention according to the refrigeration apparatus of the first to sixth inventions, the hydrofluoroolefin is mainly composed of tetrafluoropropene or trifluoropropene, difluoromethane and pentafluoroethane, and having a global warming potential of 5 As the working refrigerant, a mixed refrigerant obtained by mixing two components or three components so as to be 750 or less is used. According to this configuration, it is possible to provide a highly reliable and highly efficient rotary compressor.

The ninth invention is a refrigerator oil particularly used as a working refrigerant in the refrigerator according to the first to eighth inventions, as a refrigerator oil, polyoxyalkylene glycols, polyvinyl ethers, poly (oxy) alkylene glycol or monoether thereof Or a synthetic oil mainly composed of a copolymer of polyvinyl ether, a polyol ester, or an oxygen-containing compound of polycarbonates, or a synthetic oil mainly composed of alkylbenzenes or α-olefins. According to this configuration, it is possible to provide a highly reliable and highly efficient rotary compressor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the embodiment.

Embodiment 1
FIG. 1 shows a cycle diagram of the refrigeration system in Embodiment 1 of the present invention. The same reference numerals in FIG. 1 as those in the conventional refrigeration system in FIG.

In FIG. 1, the refrigeration system connects a compressor 120, a condenser 121, an expansion mechanism (for example, an expansion valve or capillary tube) 122, and an evaporator 123 through a circulation path to form a refrigeration cycle. There is.

The compressor 120 compresses low temperature, low pressure refrigerant gas, discharges high temperature, high pressure refrigerant gas, and sends it to the condenser 121. The refrigerant gas sent to the condenser 121 is sent to the expansion mechanism 122 as a high-temperature, high-pressure refrigerant liquid while releasing its heat into air. The high-temperature, high-pressure refrigerant liquid passing through the expansion mechanism 122 becomes a low-temperature, low-pressure wet vapor by the throttling effect, and is sent to the evaporator 123. The refrigerant that has entered the evaporator 123 absorbs heat from the surroundings and evaporates, and the low-temperature, low-pressure refrigerant gas that has left the evaporator 123 is sucked into the rotary compressor 120. Thereafter, the above cycle is repeated.

The hydrofluoroolefin refrigerant used in the refrigerator may be decomposed by oxidation in a high temperature environment to generate hydrogen fluoride, and simultaneously cause a polymerization reaction to form a polymer.

In the refrigeration apparatus, a motor unit 102 and a discharge portion 115, which will be described later, in the compressor 120 become high temperature, and the sliding portion becomes further high temperature. At such high temperature portions, as described above, the hydrofluoroolefin refrigerant may undergo a polymerization reaction to form an oligomer and an organic solid polymer.

In the present embodiment, the refrigeration oil 103 (described later) during operation of the compressor 120 has a kinematic viscosity of 0.1 mm ² / s or more and 100 mm ² / s or less. The refrigeration oil 103 is compatible with the working refrigerant, and the solubility in the refrigeration oil 103 changes depending on the pressure and temperature when the compressor 120 is operated. Since the kinematic viscosity of the refrigerator oil 103 changes according to the solubility of the working refrigerant, the actual viscosity during operation of the compressor 120 is secured. As a result, it is possible to maintain an accurate oil film strength corresponding to the pressure and temperature conditions in the actual operating range, without depending on the viscosity under the atmosphere. For this reason, generation | occurrence | production of the high temperature in a sliding part can be suppressed, and high reliability can be maintained.

Generally, in the refrigeration system, the kinematic viscosity of the refrigeration oil 103 is most reduced at startup. This is because a large amount of working refrigerant dissolves into the refrigerator oil 103 when the ambient temperature becomes low at the time of stop. In the confirmation experiment of the present invention, it was confirmed that the generation of a polymer does not occur if the actual oil viscosity at the start is 0.1 mm ² / s or more. When the kinematic viscosity of the refrigerator oil 103 is increased, the reliability of the sliding portion is improved but the kinematic viscosity is increased. Accordingly, the high viscosity refrigerant oil 103 is stirred in the rotation and sliding portions of the compressor 120, and the pressure loss increases. When a typical refrigeration system performance measurement is performed in the confirmation experiment and the kinetic viscosity of the refrigeration oil 103 is greater than 100 mm ² / s, the required input power to the compressor 120 is higher than that of the conventional refrigeration oil 103 It was confirmed to increase by 10% or more. From this, the influence in terms of performance becomes large, and it is practical to use one having a kinematic viscosity of 100 mm ² / s or less as the refrigerator oil 103.

FIG. 2 shows a longitudinal sectional view of the rotary compressor according to the first embodiment of the present invention. In FIG. 2 and FIG. 3 described later, the same components as those of the conventional refrigeration system shown in FIG. 4 and FIG.

The stator 102 a of the motor 102 is fixed to the upper part of the closed vessel 101, and the compressor rear part 105 is fixed to the lower part of the closed vessel 101. The compression mechanism portion 105 has a shaft 104 driven by the rotor 102b. The main bearing 107 is fixed to the upper end of the cylinder 106 of the compression mechanism portion 105, and the auxiliary bearing 108 is fixed to the lower end by a bolt or the like. A piston 109 is inserted into the eccentric portion 104 a of the shaft 104 in the cylinder 106 to perform eccentric rotation. A vane 110 is inserted into a vane groove 106 a of the cylinder 106, and a vane spring 111 is installed on a back surface portion 110 b of the vane 110. The tip 110 a of the vane 110 is urged to abut on the outer periphery of the piston 109.

Further, tetrafluoropropene (hereinafter, referred to as HFO 1234yf refrigerant), which is a kind of hydrofluoroolefin having a double bond between carbons, is enclosed in the closed container 101. At the bottom of the closed vessel 101, refrigeration oil 103 containing a base oil compatible with the HFO 1234yf refrigerant is stored. In the present embodiment, it is possible to use a refrigerator oil 103 containing as a main component at least one of polyol ester, polyvinyl ether and polyalkylene glycol base oil. Of the three types of refrigeration oil 103 of the present embodiment, refrigeration oil 103 containing as a main component only a polyol ester is used.

Here, the polyol ester type refrigerator oil 103 is synthesized by the dehydration reaction of polyhydric alcohol and saturated or unsaturated fatty acid. As the polyhydric alcohol, neopentyl glycol, pentaerythritol, dipentaerythritol, etc. are used according to the viscosity of the refrigerator oil 103. As one saturated fatty acid, linear fatty acids such as hexanoic acid, heptanoic acid, nonanoic acid, decanoic acid, etc., or 2-methylhexanoic acid, 2-ethylhexanoic acid, 3,5,5-trimethylhexanoic acid, etc. Branched chain fatty acids are used. It should be noted that polyol ester oils containing linear fatty acids have good sliding properties but poor hydrolyzability, and ester oils containing branched chain fatty acids have slightly poor sliding properties but are difficult to hydrolyze.
As the refrigeration oil, synthetic oil mainly composed of polyoxyalkylene glycols, polyvinyl ethers, or oxygen-containing compounds of polycarbonates, or synthetic oil mainly composed of alkylbenzenes or α-olefins may be used. it can.

Further, the refrigeration oil 103 of the present embodiment includes various additives such as a sulfur-based extreme pressure additive, an antioxidant such as dibutyl-p-cresol, an acid scavenger such as an epoxy-containing compound, and an antifoamer. , Add singly or selectively. Sulfur-based extreme pressure additives include sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dialkyl polysulfides, dibenzyl disulfides, oligomer polysulfides and the like. It is preferable that the number of crosslinking of sulfur of these sulfur-based extreme pressure additives is 3 or less. If the number of crosslinks of sulfur is 4 or more, sulfur is likely to be released into the refrigerator oil 103, which may corrode copper used in piping and the like in the refrigeration cycle, which is not preferable. Further, it is preferable to use a metal deactivator for the purpose of preventing sulfur copper corrosion. In this embodiment, benzotriazoles are used as the metal deactivator. A phosphorus-based extreme pressure additive may be used to improve the extreme pressure effect. Phosphorus-based extreme pressure additives such as phosphoric acid esters such as tricresyl phosphate and triphenyl phosphate, phosphorous acid esters, amine salts of acidic phosphoric acid esters, etc. are used, but they are excellent in compatibility with refrigerator oil 103. Acidic phosphoric acid esters such as tricresyl phosphate and triphenyl phosphate are most suitable. Since the phosphorus-based extreme pressure additive is effective from a load lower than that of the sulfur-based extreme pressure additive, using the sulfur-based extreme pressure additive and the phosphorus-based extreme pressure additive in combination can operate in a wide frequency range by inverter control. It is suitable for use in a compressor of a refrigeration cycle that is

The compressor used in the present embodiment is a general rotary compressor, in which the piston 109 eccentrically rotates in the cylinder 106 and sucks, compresses, and discharges the refrigerant while pushing the tip portion 110 a of the vane 110. is there. Therefore, a surface treatment film is formed on the tip end portion 110a of the vane 110 which is a sliding portion. Specifically, CrN, DLC, TiN and the like can be mentioned. The surface treatment film of the tip end portion 110a of the vane 110 has a polarity maintaining effect, and is constituted by dispersing, for example, graphite to which a benzene ring is connected. When the refrigerator oil 103 approaches, the polarity is induced by the polarity, polarization occurs in the surface treatment film, and the polarity is exhibited. As a result, the extreme pressure additive in the refrigerator oil 103 is adsorbed to form an extreme pressure layer. If the extreme pressure layer formed causes severe sliding conditions, for example, leaving it for half a day at a low outside air temperature of -10 ° C or less and starting with heating to start operation at maximum capacity, the lubricating oil in the sliding part seems to be insufficient become. However, as the extreme pressure layer is sufficiently formed on the sliding portion as in the present embodiment, abnormal wear of the sliding portion does not occur.

The operation and operation of the rotary compressor configured as described above will be described below with reference to FIG.

First, the HFO 1234yf refrigerant is drawn into the suction chamber 113 from the suction port 112 provided in the cylinder 106. The compression chamber 114 is composed of the vane 110, the piston 109, the cylinder 106, etc. The refrigerant in the compression chamber 114 is compressed along with the leftward rotation (in the arrow direction) of the piston 109 and is discharged through the discharge notch 115. It is discharged into the sealed container 101 from (not shown). The refrigerant gas discharged into the closed container 101 is discharged from the discharge pipe 116 in the upper part of the closed container 101 through the gap of the motor 102, and the mist of the refrigerator oil 103 in the upper part of the closed container 101 is also discharged together Be done.

In terms of the configuration of the rotary compression mechanism, the sliding state of the contact sliding portion between the tip 110a of the vane 110 and the outer periphery of the piston 109 is the most severe. Besides the vane spring 111, a high pressure discharge pressure is applied to the back surface portion 110b of the vane 110, and a large force due to a pressure difference with the pressure in the cylinder 106 is acting. Therefore, the contact state between the tip 110a of the vane 110 and the outer periphery of the piston 109 is mixed lubrication or boundary lubrication, which is in a severe environment.

Here, steel such as SKH (high-speed tool steel), SKD, SUS, SCM or the like which has been subjected to nitriding treatment is used as a base material of the vanes 110. Moreover, as a base material of the vane 110, a sintered alloy steel that has been subjected to a sintering treatment or a quenching treatment may be used. Here, the sintered alloy steel is preferably a high speed tool steel (sintered high speed tool steel).
A surface treatment film made of a ceramic such as chromium nitride (hereinafter referred to as CrN) or diamond like carbon (hereinafter referred to as DLC) is applied to the surface of the tip portion 110a of the vane 110 by a PVD treatment method. The surface hardness is about HV1500 to 2000, and the surface roughness of the tip 110a of the vane 110 which is a sliding surface is about 0.2 μm Ra. Alternatively, ceramics may be used as the base of the vanes 110.

On the other hand, the base material of piston 109 contains 0.7 to 1.0 wt% of chromium (Cr), 0.2 to 0.4 wt% of molybdenum (Mo), and 0.2 to 0.4 wt% of nickel (Ni) Cast iron (hereinafter, cast iron containing Mo, Cr, and Ni is referred to as moniclo cast iron). Then, the base material of the piston 109 is subjected to quenching, subzero, tempering, cooling, etc., to make the surface hardness about 50 to 51 HRC. In addition, since microrecesses made of graphite are present on the outer periphery of the piston 109 which is a sliding surface, the surface roughness of the flat portion excluding the microrecesses is finished to about Ra 0.2 μm.

The tetrafluoropropene (HFO 1234 yf) used in the present embodiment reduces the temperature difference despite the non-azeotropic refrigerant mixture by mixing the hydrofluorocarbon (HFC 32 and HFC 125) having no double bond. The behavior approaches that of a quasi-azeotropic mixed refrigerant. Therefore, the cooling performance and the cooling performance coefficient (COP) of the cooling device can also be improved. In the present embodiment, tetrafluoropropene (HFO 1234 yf) is used alone, but trifluoro propene (HFO 1234ze) may be used alone.

Here, with respect to GWP of the mixed refrigerant, it is necessary to perform two-component mixing or three-component mixing so as to be 5 or more and 750 or less, preferably 350 or less. In order to mix HFO 1234yf with HFC 32 to have GWP 350 or less, it is desirable that HFO 1234 yf be 48.5 wt% or more. Moreover, in order to mix HFO 1234yf and HFC 125 to make GWP 750 or less, it is desirable that HFO 1234 yf be 78.7 wt% or more. Furthermore, in order to set it as GWP 350 or less, it is desirable for HFO1234yf to be 91.6 wt% or more. By this, even if the refrigerant which is not recovered is released to the atmosphere, its influence on global warming can be kept minimal.
Note that HFO1234ze may be used instead of HFO1234yf, or a mixture of HFO1234yf and HFO1234ze may be used.

In the present embodiment, a polyol ester oil compatible with HFO 1234yf is used as the refrigerator oil 103. However, even using refrigerator oil 103 composed of similarly compatible polyvinyl ether or polyalkylene glycol, it is possible to recover the refrigerator oil 103 that has been discharged to the refrigeration cycle to the compressor 120, and it is also reliable. It is possible to obtain a high-performance compressor 120. In addition, the same refrigeration oil can be used as a refrigerant mixed with an HFC refrigerant, so that the same effect can be obtained.

Further, in the present embodiment, the rotary compressor has been described as an example of the compressor, but it may be any other known type of compressor such as a scroll compressor.

As described above, the refrigeration apparatus according to the present invention may damage or deteriorate the refrigeration apparatus by using a refrigerator oil suitable for the refrigeration cycle even when using a low GWP refrigerant having a property of easily generating a polymer. And the performance deterioration of the refrigeration cycle can be suppressed. Therefore, the present invention can be applied to many applications such as air conditioners, car air conditioners, refrigerator-freezers, dehumidifiers, heat pump type drying and washing machines, heat pump type water heaters, beverage vending machines and the like.

Claims

A single refrigerant of hydrofluoroolefin having a double bond between carbon and carbon is used as a working refrigerant, or a mixed refrigerant obtained by mixing a hydrofluorocarbon having no double bond with the hydrofluoroolefin is used as a working refrigerant, and The compressor is provided with a refrigerant circulation path, and the compressor is filled with a refrigerator oil having a kinetic viscosity of 0.1 mm 2 / s or more and 100 mm 2 / s or less during operation. And refrigeration equipment.
The freezing apparatus according to claim 1, wherein an acid scavenger is contained in the refrigerating machine oil.
The antifreeze agent was contained in the said refrigerating machine oil, The freezing apparatus of Claim 1 or Claim 2 characterized by the above-mentioned.
The compression mechanism portion of the compressor has a piston and a vane in a cylinder, and the vane is a high speed tool steel subjected to nitriding treatment, or a sintered alloy steel subjected to sintering or quenching treatment The refrigerator according to any one of claims 1 to 3, characterized in that
The refrigeration apparatus according to claim 4, wherein the sintered alloy steel is a high speed tool steel.
The compression mechanism portion of the compressor has a piston and a vane in a cylinder, and the vane uses a ceramic or an iron-based substrate whose surface is treated with a ceramic. The freezing apparatus in any one of 3.
The hydrofluoroolefin is mainly composed of a single refrigerant of tetrafluoropropene or trifluoropropene, or the tetrafluoropropene or the trifluoropropene as a main component, and each component is a two component so that the global warming potential is 5 or more and 750 or less. The refrigeration system according to any one of claims 1 to 6, wherein a mixed refrigerant obtained by mixing or three components is used as a working refrigerant.
The hydrofluoroolefin contains tetrafluoropropene or trifluoropropene as a main component, and is a mixture of difluoromethane and pentafluoroethane mixed in two or three components so that the global warming potential is 5 or more and 750 or less. The refrigeration apparatus according to any one of claims 1 to 6, wherein the refrigerant is a working refrigerant.
Synthesis as the main component of the refrigeration oil is polyoxyalkylene glycols, polyvinyl ethers, poly (oxy) alkylene glycols or copolymers of monoethers thereof and polyvinyl ethers, polyol esters, or oxygen-containing compounds of polycarbonates The refrigeration apparatus according to any one of claims 1 to 8, wherein the oil is an oil, or a synthetic oil containing an alkylbenzene or an alpha-olefin as a main component.