WO2022024342A1

WO2022024342A1 - Refrigeration cycle apparatus and compressor

Info

Publication number: WO2022024342A1
Application number: PCT/JP2020/029430
Authority: WO
Inventors: 研吾平塚; 悟外山; 健嗣小島; 愛実中村
Original assignee: 三菱電機株式会社
Priority date: 2020-07-31
Filing date: 2020-07-31
Publication date: 2022-02-03

Abstract

This refrigeration cycle apparatus comprises a refrigeration circuit that includes a compressor, wherein a refrigerant is sealed inside the refrigeration circuit. The refrigerant contains trifluoroiodomethane and has a global warming potential of not more than 750. The compressor is provided with a compressing mechanism unit that compresses the refrigerant and a motor that drives the compressing mechanism unit. The motor is provided with a rotor and a stator. The stator includes an insulating film made of polyester. In the refrigeration cycle apparatus, the inside of the compressor is filled with refrigerator oil. The refrigerator oil contains alkylnaphthalene as an in-oil additive.　Also provided is a compressor for use in a refrigeration cycle apparatus that is provided with a refrigeration circuit in which a refrigerant circulates, said compressor comprising: a compressing mechanism unit that compresses the refrigerant; and a motor that drives the compressing mechanism unit. The refrigerant contains trifluoroiodomethane and has a global warming potential of not more than 750. The motor is provided with a rotor and a stator. The stator includes an insulating film made of polyester. The inside of the compressor is filled with refrigerator oil. The refrigerator oil contains alkylnaphthalene as an in-oil additive.

Description

Refrigeration cycle device and compressor

This disclosure relates to a refrigeration cycle device and a compressor.

Conventionally, various measures against climate change have been reported internationally to prevent global warming. In particular, the refrigerant used in the refrigeration cycle apparatus is being replaced with a refrigerant having a lower global warming potential (GWP) than R410A, which has been mainly used in the past. R410A is a pseudo-azeotropic mixed refrigerant of difluoromethane (R32) and pentafluoroethane (R125), and GWP is 2088.

In recent years, in areas where flammable refrigerants can be used, such as Japan and Europe, the replacement of R410A with R32 (GWP: 675) is progressing. However, since R32 is a slightly flammable refrigerant, R32 cannot be used in North America and the like where the use of flammable refrigerant is legally regulated.

And since GWP and flammability are generally in a contradictory relationship, it is difficult to achieve both low GWP and nonflammability at the same time. Therefore, it is desired to develop a refrigerant having both low GWP and nonflammability.

Under such circumstances, R466A has been proposed. R466A is a refrigerant in which R32, R125 and trifluoroiodomethane (R13I1) are mixed at a mass ratio of 49.0% by mass, 11.5% by mass and 39.5% by mass, respectively, and has a higher GWP than 733 and R410A. It is low and nonflammable. As described above, R466A is a refrigerant having both low GWP and nonflammability.

Further, Patent Document 1 (Patent No. 6545338) and Patent Document 2 (Patent No. 6545337) disclose a refrigerating cycle apparatus using a refrigerant mixed with R32, R125 and trifluoroiodomethane. There is. This mixed refrigerant also has a GWP of 750 or less, a lower GWP than R410A, and a lower combustibility than R32, and is a refrigerant having both low GWP and low combustibility.

Japanese Patent No. 6545338 Japanese Patent No. 6545337

However, the CI bond contained in trifluoroiodomethane has a lower binding energy than the CF bond contained in R32 and R125, and trifluoroiodomethane is thermally unstable as compared with R32 and R125. .. When the CI bond of trifluoroiodomethane is cleaved in a high temperature environment, a trifluoromethyl radical (CF ₃ ·) and an iodine radical (I ·) are generated. The generated trifluoromethyl radicals and iodine radicals include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) and polybutylene naphthalate (PBN), which are used as insulating films in compressors. Reacts with polyester to accelerate the deterioration of the compressor in the refrigeration cycle device.

Therefore, with the thermal decomposition of trifluoroiodomethane, not only the performance of the refrigeration cycle device deteriorates, but also the reliability of the compressor may not be ensured. In particular, since the temperature of the motor part in the compressor becomes high, the temperature rises when the refrigerant containing trifluoroiodomethane passes around the motor part, and as a result of the above-mentioned thermal decomposition, there is a problem of causing various harmful effects. rice field.

The present disclosure has been made in view of the above problems, and provides a refrigerating cycle apparatus and a compressor capable of suppressing the generation of radicals due to the decomposition of trifluoroiodomethane and ensuring reliability over a long period of time. The purpose.

The refrigerating cycle apparatus according to the present disclosure includes a refrigerating circuit including a compressor, and a refrigerant is sealed in the refrigerating circuit. The refrigerant contains trifluoroiodomethane and has a global warming potential of 750 or less. The compressor includes a compression mechanism unit that compresses the refrigerant and a motor that drives the compression mechanism unit. The motor comprises a rotor and a stator, the stator including an insulating film made of polyester. The compressor is filled with refrigerating machine oil, and the refrigerating machine oil contains alkylnaphthalene as an additive in the oil.

The compressor according to the present disclosure is a compressor used in a refrigeration cycle device including a refrigeration circuit in which a refrigerant circulates, and includes a compression mechanism unit for compressing the refrigerant and a motor for driving the compression mechanism unit. The refrigerant contains trifluoroiodomethane and has a global warming potential of 750 or less. The motor comprises a rotor and a stator, the stator including an insulating film made of polyester. The compressor is filled with refrigerating machine oil, and the refrigerating machine oil contains alkylnaphthalene as an additive in the oil.

According to the present disclosure, it is possible to provide a refrigerating cycle apparatus and a compressor capable of suppressing the generation of radicals due to the decomposition of trifluoroiodomethane and ensuring reliability over a long period of time.

It is a schematic block diagram which shows the refrigerating cycle apparatus which concerns on Embodiment 1. FIG. It is sectional drawing which shows the motor of the compressor which concerns on Embodiment 1. FIG.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
Embodiment 1.
First, the outline of the refrigerating cycle apparatus of this embodiment will be briefly described. FIG. 1 is a schematic configuration diagram showing a refrigeration cycle apparatus according to the first embodiment. In the refrigeration cycle device 100, the compressor 1, the condenser 2, the expansion valve 3, and the evaporator 4 are connected by a refrigerant pipe 5, respectively, and the compressor 1, the condenser 2, the expansion valve 3, and the evaporator 4 are connected. A refrigeration cycle in which the refrigerant circulates inside is configured in the order of the compressor 1. Of the refrigerant pipes 5, the one connecting the compressor 1 and the condenser 2 is the refrigerant pipe 5a, the one connecting the condenser 2 and the expansion valve 3 is the refrigerant pipe 5b, and the expansion valve 3 and the evaporator 4 are connected. The one connected to the refrigerant pipe 5c is referred to as a refrigerant pipe 5c, and the one connected to the evaporator 4 and the compressor 1 is referred to as a refrigerant pipe 5d. The refrigerant that circulates in the refrigeration cycle device 100 according to the first embodiment is not particularly limited, but is determined to be any one refrigerant depending on the application of the refrigeration cycle device 100 and the like.

The compressor 1 sucks in the refrigerant, compresses it, makes it into a high-temperature and high-pressure gas state, and discharges it. The compressor 1 may be configured such that the rotation speed is controlled by, for example, an inverter circuit or the like, and the discharge amount of the refrigerant can be adjusted by controlling the rotation speed.

In the condenser 2, the refrigerant compressed by the compressor 1 into a high-temperature and high-pressure gas state flows in, and heat exchange is performed between the refrigerant and the heat source to cool the refrigerant into a low-temperature and high-pressure liquid state. Examples of the heat source include air, water, brine, and the like. In the first embodiment, the heat source of the condenser 2 is outside air, which is outdoor air, and the condenser 2 exchanges heat between the outside air and the refrigerant. Further, in the first embodiment, in order to promote heat exchange of the condenser 2, the condenser blower 6 is provided to blow outside air to the condenser 2 when the refrigerant is circulating in the refrigeration cycle device 100. The condenser blower 6 may be configured so that the air volume can be adjusted.

The expansion valve 3 is filled with a low-temperature, high-pressure liquid-state refrigerant cooled by the condenser 2, and the refrigerant is decompressed and expanded to a low-temperature, low-pressure liquid state. The expansion valve 3 is composed of, for example, a refrigerant flow rate control means such as an electronic expansion valve or a temperature-sensitive expansion valve, a capillary tube, or the like.

In the evaporator 4, a low-temperature low-pressure liquid refrigerant expanded under reduced pressure by the expansion valve 3 flows in, exchanges heat between the refrigerant and the cooling target, absorbs the heat of the cooling target into the refrigerant, and cools the target. To cool. When cooling the object to be cooled, the refrigerant evaporates to a high temperature and low pressure gas state. In the first embodiment, the cooling target is indoor air, and the evaporator 4 exchanges heat between the indoor air and the refrigerant. Further, in the first embodiment, in order to promote heat exchange of the evaporator 4, the evaporator blower 7 is provided to blow indoor air to the evaporator 4 when the refrigerant is circulating in the refrigeration cycle device 100. .. The evaporator blower 7 may be configured so that the air volume can be adjusted.

The compressor 1 sucks the refrigerant that has become a high-temperature and low-pressure gas state by the evaporator 4, and compresses it again, so that the refrigerant circulates in the refrigeration cycle device 100.

The refrigerating cycle device 100 may be, for example, any device capable of performing both cooling and heating, a device capable of only cooling, or a device capable of only heating, and may be used in various refrigerating and air-conditioning devices. Applicable.

(Refrigerant)
Next, in the present embodiment, the refrigerant enclosed in the refrigeration circuit will be described. The refrigerant contains trifluoroiodomethane. For example, it may be a single refrigerant of trifluoroiodomethane, or it may be a mixed refrigerant in which trifluoroiodomethane is mixed with another refrigerant. Further, an additive may be added to the refrigerant, or an additive may not be added to the refrigerant. Trifluoroiodomethane has an extremely low GWP of 0.4, and is classified as nonflammable (Class 1) in ANSI / ASHRAE Standard 34-2019. Therefore, by including trifluoroiodomethane, the refrigerant can obtain the characteristics of low combustibility with GWP.

Further, the refrigerant has a GWP of 750 or less. When the GWP is 750 or less, the refrigerant has excellent environmental performance and is highly compliant with legal regulations. Further, the refrigerant having a GWP of 750 or less can be used as a refrigerating cycle device not only in a refrigerator but also in an air conditioner. As the GWP, the value (100-year value) of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) is used. Further, as the GWP of the refrigerant not described in AR5, the value described in other known documents may be used, or the value calculated or measured by using a known method may be used.

Further, the refrigerant is preferably a refrigerant whose combustibility classification is classified as non-combustible (Class 1) in ANSI / ASHRAE Standard 34-2019. When using a refrigerant classified as nonflammable, the means, equipment or structure for diffusing the leaked refrigerant to the refrigeration cycle device, the sensor for detecting the refrigerant leak, and the alarm issued when the sensor detects the refrigerant leak. There is no need to provide a device. Refrigerants classified as nonflammable can also be used in areas where the use of flammable refrigerants is not permitted by legal regulations.

Further, it is preferable that the refrigerant contains R32. By including R32, high refrigerating capacity and high energy efficiency can be ensured. Further, it is more preferable that the refrigerant further contains R125 in addition to R32. By including R125, the temperature gradient, which is the temperature difference between the start temperature and the end temperature of the phase change of the refrigerant, can be reduced. Therefore, the mixed refrigerant of trifluoroiodomethane, R32 and R125 can obtain the characteristics of low flammability with GWP. Further, by using a mixed refrigerant, a refrigerating cycle device having excellent refrigerating capacity and energy efficiency can be obtained.

Further, the refrigerant is more preferably a refrigerant containing 40% by mass or less of trifluoroiodomethane. This is because the refrigerant is a mixed refrigerant having an operating pressure close to that of R410A, and is a refrigerant that can be easily used as a substitute refrigerant for R410A. Further, in the case of a refrigerant containing 40% by mass or less of trifluoroiodomethane, the ratio of trifluoroiodomethane decreases, so that the amount of radicals generated by the decomposition of trifluoroiodomethane decreases, and the insulating film described later Degradation reaction is suppressed. On the other hand, when the ratio of trifluoroiodomethane in the refrigerant is 40% by mass or more, the amount of radicals generated by the decomposition of trifluoroiodomethane increases and the deterioration reaction of the insulating film occurs, so that the tensile stress of the insulating film occurs. May be significantly reduced and the insulating film may become brittle.

According to REFPROP version 10.0 (manufactured by NIST), which is a refrigerant thermal property database software, the saturated vapor pressure of trifluoroiodomethane is 0.49 MPa at 25 ° C, while the saturated vapor pressure of R410A is 1.66 MPa at 25 ° C. And trifluoroiodomethane is a very low pressure refrigerant. Therefore, when the ratio of trifluoroiodomethane in the refrigerant is high, the operating pressure of the mixed refrigerant may be much lower than that of R410A.

For example, in a composition in which trifluoroiodomethane is mixed with R410A and the ratio of trifluoroiodomethane is 40% by mass (R32, R125 and R13I1 are mixed at 30% by mass, 30% by mass and 40% by mass, respectively). The saturated vapor pressure at 25 ° C is 1.65 MPa, which is equivalent to R410A, but the composition is 50% by mass of trifluoroiodomethane (25% by mass, 25% by mass and 50% by mass of R32, R125 and R13I1 respectively). % Mixing), the saturated vapor pressure at 25 ° C. is 1.53 MPa, and the saturated vapor pressure is 7% lower than that of R410A.

The refrigerant contains 39% by mass or more and 40% by mass or less of trifluoroiodomethane, R32 47% by mass or more and 49.5% by mass or less, and R125 11% by mass or more and 13.5% by mass or less, and has a mass ratio of trifluoroiodomethane. The sum of the mass ratio of difluoromethane and the mass ratio of pentafluoroethane is preferably 100% by mass.

Among them, it is more preferable that the refrigerant contains 39.5% by mass of trifluoroiodomethane, 49% by mass of R32 and 11.5% by mass of R125. The refrigerant having such a composition has a GWP of 733 and is classified into a non-combustible category (Class 1).

Further, the refrigerant may be a mixed refrigerant of a halogenated hydrocarbon having an unsaturated bond and trifluoroiodomethane, or a refrigerant obtained by mixing them with hydrofluorocarbons such as R32, R125, R134a, R152a and R41. A halogenated hydrocarbon having an unsaturated bond has at least one carbon-carbon double bond or carbon-carbon triple bond and further has at least one halogen element (F, Cl, Br or I). It is a hydrocarbon. Halogenated hydrocarbons having unsaturated bonds have a lower GWP than hydrofluorocarbons such as R32 and R125, and can be mixed to lower the GWP of the refrigerant.

Specific examples of the halogenated hydrocarbon having an unsaturated bond include hydrofluoroolefins such as HFO1141, R1132a, HFO1132 (E), HFO1132 (Z), and HFO1123, HFO1225ye (Z), HFO1225ye (E), HFO1225zc, and R1234yf. , R1234ze (E), HFO1234ze (Z), HFO1234ye (Z), HFO1234ye (E), HFO1243zf, HFO1252zf, HFO1261yf and other hydrofluoropropylenes, R1336mzz (E), R1336mzz (Z) E), HFO1336yf, HFO1336pyy, HFO1327cze, HFO1327et, HFO1327, HFO1345czf, HFO1345fyc, HFO1345cye, HFO1345cyf, HFO1345eye, HFO1345pyz, HFO1345pyy (E), HFO1345pyy (Z), HFO1345zy (E), Ya hydrofluoroether butene such HFO1345zy (Z) , R1224yd (Z), R1233zd (E) and the like hydrochlorofluoropropylene, PFO1216 and the like perfluoroolefin, and the like. In particular, in order to make the refrigerant a mixed refrigerant having an operating pressure close to that of R410A, hydrofluoroethylene or hydrofluoropropylene is preferable among the halogenated hydrocarbons having unsaturated bonds, and among them, R1132a, HFO1132 (E) and HFO1132 ( Z), HFO1123, HFO1225ye (Z), HFO1225ye (E), HFO1225zc, R1234yf, R1234ze (E), HFO1234ze (Z), HFO1234ye (Z), HFO1234ye (E) are preferable.

Further, the effect of suppressing deterioration of the insulating film due to the radical scavenging effect of alkylnaphthalene, which will be described later, is also effective for the above-mentioned halogenated hydrocarbon having an unsaturated bond. Further, the halogenated hydrocarbon having an unsaturated bond has low compatibility with alkylnaphthalene, which will be described later.

The above-mentioned example of a halogenated hydrocarbon having an unsaturated bond is an example of a halogenated hydrocarbon having an unsaturated bond according to the present disclosure, and the present disclosure is not limited to these examples.

(Compressor)
Next, the compressor of the refrigeration cycle apparatus according to the first embodiment will be described. FIG. 2 is a cross-sectional view showing a motor of the compressor according to the first embodiment. The compressor 1 includes a closed container 8. The closed container 8 is provided with a compression mechanism portion 9 inside, and a suction pipe 10 for inflowing the refrigerant into the inside and a discharge pipe 11 for flowing out the refrigerant to the outside are connected to each other. The compression mechanism unit 9 is configured to compress the refrigerant contained in the closed container 8 from the suction pipe 10 and discharge it from the discharge pipe 11.

The motor 16 includes a rotor 17 and a stator 18. The rotor 17 is a cylindrical component provided with a magnet, and is arranged in a hole of a ring-shaped stator 18. By supplying electric power to the stator 18, the rotor 17 rotates about the central axis of the motor 16. The rotor 17 is provided with a hole for the refrigerant compressed by the compression mechanism portion 9 to pass through, and the refrigerant is discharged from the discharge pipe 11 to the refrigerant pipe 5a after passing through the hole.

Trifluoroiodomethane cleaves CI bonds at high temperatures to generate trifluoromethyl radicals (CF ₃ ·) and iodine radicals (I ·). In particular, since the motor 16 generates heat and becomes high in temperature, decomposition when the refrigerant containing trifluoroiodomethane passes around the motor 16 becomes a problem.

The product extracts hydrogen atoms from the organic compound in the refrigeration circuit to produce R23 (CHF ₃ ) and hydrogen iodide (HI). In particular, in the compound having an ester bond (-COO-), the charge is biased in the molecule due to the oxygen atom having a high electronegativity, and the hydrogen atom bonded to the carbon atom on both sides of the ester bond is supplied to the radical. , May be disassembled. As an example, the reaction of extracting a hydrogen atom from an ester by a trifluoromethyl radical is shown below (the wavy line in the chemical formula is an arbitrary substituent).

The ester compound radicalized by the above reaction extracts hydrogen atoms from the surrounding molecules in the refrigeration cycle apparatus 100, and is converted into peroxy radicals (ROO ·) or radicals by the reaction with the oxygen molecules mixed in the refrigeration cycle apparatus 100. Due to a chain reaction such as recombination between each other, the compound changes to a different compound, and the characteristics change.

Examples of the ester compound in the refrigeration cycle apparatus 100 include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polybutylene naphthalate (PBN), which are used as insulating films in the stator 18 of the motor 16. ) And the like.

When the above-mentioned chain reaction occurs in the insulating film, the mechanical strength of the insulating film may decrease, the insulating film may break, and the reliability of the compressor 1 may be impaired. In the present disclosure, radicals (CF ₃ and I) generated by decomposition of trifluoroiodomethane are made by setting the trifluoroiodomethane content in the refrigerant to 40% by mass or less in order to suppress the deterioration reaction of the insulating film.・) Suppress the amount of production.

Further, even when radicals are generated, alkylnaphthalene (AN) is mixed as an additive in oil in the refrigerating machine oil so as not to deteriorate the polyester in the refrigerating cycle apparatus 100, and radicals are generated by the radical scavenging effect of alkylnaphthalene. Reduce the amount. Alkylnaphthalene is a polycyclic aromatic hydrocarbon compound represented by the following chemical formula 2.

In the above chemical formula 2, R ₁ to R ₈ are an alkyl group or a hydrogen atom. R ₁ to R ₈ may be the same or different.

Further, the physical properties such as viscosity and pour point differ depending on the structure of R ₁ to R ₈ . The structures of R ₁ to R ₈ may be any structure, but those having excellent low temperature fluidity are preferable. From the viewpoint of low-temperature fluidity, the molecular weight of alkylnaphthalene is preferably 268 g / mol or more and 423 g / mol or less, and more preferably 296 g / mol or more and 353 g / mol or less. The number of naphthalene carbon atoms substituted with an alkyl group is preferably 1 to 3, and more preferably 2.

As an example of the molecular structure of alkylnaphthalene, alkylnaphthalene having a molecular weight of 296 g / mol and having two carbon atoms substituted with an alkyl group is shown below.

The content of alkylnaphthalene in the refrigerating machine oil is preferably 1% by mass or more and 20% by mass or less, and more preferably 4% by mass or more and 10% by mass or less with respect to the mass of the refrigerating machine oil. When the content of alkylnaphthalene in the refrigerating machine oil is less than 1% by mass with respect to the mass of the refrigerating machine oil, the radicals generated by the decomposition of trifluoroiodomethane cannot be sufficiently captured, and the insulating film due to the reaction with the radicals cannot be sufficiently captured. A deterioration reaction may occur, the tensile stress of the insulating film may be significantly reduced, and the insulating film may become brittle. In addition, the reaction of extracting hydrogen atoms from the insulating film by radicals proceeds, R23 and hydrogen iodide are generated, and there is a possibility that the GWP of the refrigerant increases and the total acid value of the refrigerating machine oil increases. On the other hand, when the content of alkylnaphthalene in the refrigerating machine oil is more than 20% by mass with respect to the mass of the refrigerating machine oil, it can be expected to be effective in suppressing the deterioration of the insulating film. There is a problem that compatibility is reduced.

(Refrigerator oil)
Next, in the present embodiment, the refrigerating machine oil filled to lubricate the sliding portion in the compressor 1 will be described. The refrigerating machine oil is stored in the lower part of the closed container 8, and the portion is referred to as an oil storage unit 13. Examples of the refrigerating machine oil include commonly used refrigerating machine oils (ester-based lubricating oil, ether-based lubricating oil, fluorine-based lubricating oil, mineral-based lubricating oil, hydrocarbon-based lubricating oil, and the like). In that case, it is preferable to select a refrigerating machine oil which is excellent in terms of compatibility with the refrigerant and stability. Specific examples of the refrigerating machine oil include, but are not limited to, polyol ester oil, polyvinyl ether oil, polyalkylene glycol oil, alkylbenzene oil, mineral oil, poly α-olefin or a mixture thereof.

Refrigerating machine oil may contain an antioxidant, an acid scavenger or an extreme pressure agent (anti-wear agent) as an additive in the oil. Antioxidants include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, and 2,2'-methylenebis (4-methyl-6-tert). -Phenols such as butylphenol), phenyl-α-naphthylamine, N. Examples thereof include amines such as N'-di-phenyl-p-phenylenediamine. Examples of the acid trapping agent include epoxy compounds such as phenylglycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, cyclohexene oxide, α-olefin oxide, and epoxidized soybean oil, but glycidyl ester, glycidyl ether, and epoxidized soybean oil are preferable. At least one of α-olefin oxides. Examples of the extreme pressure agent (wear inhibitor) include phosphorus-based extreme pressure agents such as phosphoric acid ester, acidic phosphoric acid ester, phosphite ester, acidic sulphate ester and amine salts thereof, but they are preferable. Is at least one of tricresyl phosphate, trithiophenyl phosphate, tri (nonylphenyl) phosphite, dioleyl hydrogen phosphite, and 2-ethylhexyl diphenyl phosphite.

If the refrigerating machine oil contains water, the water content in the refrigerating machine oil to be filled is controlled to 100 mass ppm or less in order to accelerate the deterioration of the refrigerant, the refrigerating machine oil and the material in the compressor.

<Evaluation test 1>
The deterioration (chemical stability) of the insulating film in the first embodiment was confirmed by an experimental method based on JIS K2211: 2009 (Appendix C autoclave test). The autoclave test is a kind of chemical stability test method with a refrigerant, and specifically, it is a test performed by the procedure described below. Put iron, copper and aluminum as catalysts in the test container, inject the sample and refrigerant, and seal. Next, the sealed test container is heated at 125 to 200 ° C. for a certain period of time, and then the chemical stability of the sample is evaluated by the color of the sample and the like.

As the refrigerant, trifluoroiodomethane (manufactured by Taiyo Nippon Sanso Co., Ltd.) is 40% by mass, R32 (manufactured by Daikin Industries, Ltd.) is 49% by mass, and R125 (manufactured by Daikin Industries, Ltd.) is 11% by mass. A mixture was used. As the refrigerating machine oil, commercially available polyvinyl ether oil (PVE oil) (manufactured by Idemitsu Kosan Co., Ltd.) was used. In PVE oil, alkylnaphthalene was mixed at a ratio of 1% by mass, 4% by mass, 10% by mass and 20% by mass with respect to the mass of PVE oil. As the alkylnaphthalene, a commercially available alkylnaphthalene-based lubricating oil (KR-007A manufactured by King Industries Inc.) was used. The water content of the refrigerating machine oil was removed by nitrogen bubbling so that the water content was less than 50 ppm. A PET film was used as a sample. Since the PET film may contain water during storage, it was dried for 4 hours while being heated to 100 ° C. in an oven (SPH-201S manufactured by ESPEC CORPORATION) before being sealed in a test container. The shape of the PET film is the size conforming to the test piece type 5 of JIS K 7127: 1999. As the catalyst, iron, copper and aluminum were used as materials specified in JIS, each having a diameter of 1.6 mm and a length of 300 mm.

A 200 cm ³ test container (portable reactor manufactured by Pressure Resistant Glass Industry Co., Ltd.) was filled with 40 g of the above-mentioned refrigerant, 40 g of alkylnaphthalene-containing PVE oil mixed at each ratio, three PET films, and the above-mentioned catalyst (Test Example 1). ~ 4), using an oven (SPH-201S manufactured by Espec Co., Ltd.), the mixture was heated at a temperature of 140 ° C. for 14 days.

The tensile stress of the heated sample was measured by an experimental method based on JIS K 7127: 1999. An autograph (AG-100kNI manufactured by Shimadzu Corporation) was used for the measurement. The retention rate of the tensile stress of the insulating film is based on the maximum value of the tensile stress of the film in the state before the test (170 MPa in the average value of three sheets), and the ratio of the maximum value of the tensile stress after the test (after the test). The average value of the maximum points of the tensile stress of the three films of No. 1/170) was used for the determination. The evaluation results are shown in Table 1 below.

According to a report by McMahon et al. (J. Chem. Eng. Data, vol. 4, No. 1, P. 57, 1959), the PET film deteriorates and the fracture strength is 2/3 (67) before the deterioration. %), It is said that it becomes brittle and its strength drops sharply. Therefore, the retention rate of tensile stress was set to 67% as a threshold value for judging that there was no problem.

As shown in Table 1 above, from the evaluation results of the tensile stress, in Test Examples 1 to 4, the retention rate of the tensile stress of the insulating film could be suppressed to the threshold value (67%) or more. This result is also expected for PBT, PEN and PBN, which deteriorate upon reaction with radicals generated by the decomposition of trifluoroiodomethane as well as PET.

<Evaluation test 2>
The compatibility of refrigerating machine oil and refrigerant to which alkylnaphthalene was added was evaluated by an experimental method based on JIS K2211: 2009 (Appendix D Refrigerant compatibility test method).

The refrigerant, refrigerating machine oil, and alkylnaphthalene used were those described in Evaluation Test 1, respectively. PVE oil is not mixed with alkylnaphthalene and is mixed with alkylnaphthalene at a ratio of 1% by mass, 4% by mass, 10% by mass, 20% by mass and 25% by mass with respect to the mass of PVE oil. It was used.

Alkylnaphthalene-containing PVE in which 42.5 g of the above-mentioned refrigerant and 7.5 g of PVE oil (without alkylnaphthalene) are mixed in a 96 cm ³ pressure-resistant glass test container (hyper-glass cylinder manufactured by Pressure-resistant Glass Industry Co., Ltd.). 7.5 g of oil was filled (Test Examples 5 to 10), and the state of the above mixture during cooling was visually observed using an ultra-low temperature circulator (FW95-SL manufactured by JULABO GmbH). The cooling temperature was set so that the mixture of the refrigerant and the refrigerating machine oil would be −50 ° C. in the refrigerating cycle apparatus 100. The evaluation results are shown in Table 2 below.

As shown in Table 2 above, based on the compatibility evaluation results, in Test Examples 5 to 9, PVE oil (without alkylnaphthalene) or alkylnaphthalene was added in an amount of 1% by mass, 4% by mass, based on the mass of the PVE oil. By mixing at a ratio of 10% by mass and 20% by mass, compatibility between the refrigerant and the refrigerating machine oil could be ensured while suppressing the retention rate of the tensile stress of the insulating film to the threshold value (67%) or more.

On the other hand, in Test Example 10, the compatibility between the refrigerant and the refrigerating machine oil could not be ensured by mixing alkylnaphthalene at a ratio of 25% by mass with respect to the mass of PVE oil.

From the above test results, it was found that when the content of alkylnaphthalene in the refrigerating machine oil exceeds 20% by mass with respect to the mass of the refrigerating machine oil, the compatibility between the refrigerant and the refrigerating machine oil decreases. This is because alkylnaphthalene has a lower polarity than a refrigerating machine oil having a polarity such as PVE oil and is difficult to be compatible with a highly polar refrigerant composition (trifluoroiodomethane, R32, R125, etc.). It is conceivable that the same applies to a mixed refrigerant in which the ratio of trifluoroiodomethane in the refrigerant is less than 40% by mass.

<Evaluation test 3>
The durability test of the compressor 1 was carried out using two refrigeration cycle devices 100. As the refrigerant, R466A (R32, R125: manufactured by Daikin Industries, Ltd., R13I1: manufactured by Taiyo Nippon Sanso Co., Ltd. was mixed) was used. As the refrigerating machine oil, a commercially available polyol ester oil (POE oil) (manufactured by JXTG Energy Co., Ltd.) was used. In the POE oil, alkylnaphthalene was mixed at a ratio of 4% by mass and 10% by mass with respect to the mass of the POE oil. As the alkylnaphthalene, the one described in the evaluation test 1 was used. PET was used as the insulating film. The length of the refrigerant pipes 5a to 5d was 2 m, 13 kg of R466A and 3000 cm ³ of alkylnaphthalene-containing POE oil were used. The refrigeration cycle device 100 was operated for a total of 2000 hours while switching between cooling operation and heating operation every 500 hours.

As a result, the two refrigeration cycle devices 100 and the compressor 1 continued to operate normally during the endurance test of 2000 hours.

It should be considered that the embodiments and examples disclosed this time are exemplary in all respects and not restrictive. The scope of the present disclosure is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

1 Compressor, 2 Condenser, 3 Expansion valve, 4 Evaporator, 5 Refrigerant piping, 5a-5d Refrigerant piping, 6 Condenser blower, 7 Evaporator blower, 8 Sealed container, 9 Compression mechanism, 10 Suction pipe, 11 Discharge pipe, 12 spindle, 13 oil reservoir, 14 short bearing, 15 long bearing, 16 motor, 17 rotor, 18 stator, 100 refrigeration cycle device.

Claims

Equipped with a refrigeration circuit including a compressor,
Refrigerant is sealed in the refrigeration circuit,
The refrigerant contains trifluoroiodomethane and has a global warming potential of 750 or less.
The compressor includes a compression mechanism unit that compresses the refrigerant and a motor that drives the compression mechanism unit.
The motor comprises a rotor and a stator.
The stator comprises a polyester insulating film and
The compressor is filled with refrigerating machine oil,
The refrigerating machine oil is a refrigerating cycle apparatus containing alkylnaphthalene as an additive in the oil.
The refrigerating cycle apparatus according to claim 1, wherein the refrigerant further contains difluoromethane.
The refrigerating cycle apparatus according to claim 2, wherein the refrigerant further contains pentafluoroethane.
The refrigerating cycle apparatus according to any one of claims 1 to 3, wherein the refrigerant contains 40% by mass or less of trifluoroiodomethane.
The refrigerating cycle apparatus according to any one of claims 1 to 4, wherein the refrigerating machine oil contains 1% by mass or more and 20% by mass or less of alkylnaphthalene.
The refrigerating cycle apparatus according to any one of claims 1 to 5, wherein the polyester is either polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or polybutylene naphthalate.
The refrigerating cycle apparatus according to any one of claims 1 to 5, wherein the polyester is polyethylene terephthalate.
The refrigerant contains 39% by mass or more and 40% by mass or less of trifluoroiodomethane, 47% by mass or more and 49.5% by mass or less of difluoromethane, and 11% by mass or more and 13.5% by mass or less of pentafluoroethane, and trifluoroiodomethane. The sum of the mass ratio of, the mass ratio of difluoromethane, and the mass ratio of pentafluoroethane is 100% by mass.
The polyester is polyethylene terephthalate and is
The refrigerating cycle apparatus according to claim 1, wherein the refrigerating machine oil contains 4% by mass or more and 10% by mass or less of alkylnaphthalene.
A compressor used in a refrigeration cycle device equipped with a refrigeration circuit in which a refrigerant circulates.
It is equipped with a compression mechanism that compresses the refrigerant and a motor that drives the compression mechanism.
The refrigerant contains trifluoroiodomethane and has a global warming potential of 750 or less.
The motor comprises a rotor and a stator.
The stator comprises a polyester insulating film and
The compressor is filled with refrigerating machine oil,
The refrigerating machine oil is a compressor containing alkylnaphthalene as an additive in the oil.
The compressor according to claim 9, wherein the refrigerant further contains difluoromethane.
The compressor according to claim 10, wherein the refrigerant further contains pentafluoroethane.
The compressor according to any one of claims 9 to 11, wherein the refrigerant contains 40% by mass or less of trifluoroiodomethane.
The compressor according to any one of claims 9 to 12, wherein the refrigerating machine oil contains 1% by mass or more and 20% by mass or less of alkylnaphthalene.
The compressor according to any one of claims 9 to 13, wherein the polyester is either polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or polybutylene naphthalate.
The compressor according to any one of claims 9 to 13, wherein the polyester is polyethylene terephthalate.
The refrigerant contains 39% by mass or more and 40% by mass or less of trifluoroiodomethane, 47% by mass or more and 49.5% by mass or less of difluoromethane, and 11% by mass or more and 13.5% by mass or less of pentafluoroethane, and trifluoroiodomethane. The sum of the mass ratio of, the mass ratio of difluoromethane, and the mass ratio of pentafluoroethane is 100% by mass.
The polyester is polyethylene terephthalate and is
The compressor according to claim 9, wherein the refrigerating machine oil contains 4% by mass or more and 10% by mass or less of alkylnaphthalene.