JP2020070941A - Refrigeration cycle device - Google Patents

Abstract

To provide a refrigeration cycle device preventing corrosion of a metallic member of a refrigerant circuit at low costs.SOLUTION: An air conditioning device includes: a mixed refrigerant including 20 wt.% or more of low GWP refrigerant including at least one of a refrigerant having a carbon-carbon bond excluding a single bond as a bond between carbon atoms, a refrigerant having a single bond of a hydrogen group element of an atomic weight over 10 times of carbon, and carbon, and a refrigerant having an ether bond; and a refrigerant circuit in which a refrigeration oil is circulated. In a metallic member forming the refrigerant circuit, a material not including nickel, is used as a material of the metallic member forming the refrigerant circuit, in a case where a pipe inner surface area of a connection pipe forming the refrigerant circuit is 0.6 mor more.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a refrigeration cycle device.

  R410A refrigerant, which is a hydrofluorocarbon (HFC) refrigerant, is widely used as a refrigerant in an air conditioner including a compressor that compresses a refrigerant, but the R410A refrigerant has a large global warming potential (GWP). Therefore, as a refrigerant having a relatively small GWP, a related technique using a mixed refrigerant containing a hydrofluoroolefin (HFO) refrigerant is known. In addition, related arts using a mixed refrigerant containing a hydrochlorofluoroolefin (HCFO) refrigerant are also known.

  A "refrigerant having a carbon-carbon bond other than a single bond as a bond between carbon atoms" such as an HFO refrigerant or a HCFO refrigerant is chemically unstable. Further, not only bonds between carbon atoms, but also refrigerants having bonds between carbon atoms and elements having an atomic weight exceeding a certain value than the atomic weight of carbon atoms, and refrigerants having an ether bond are chemically unstable. It has been known. Specifically, the refrigerant reacts with water and oxygen. Generally, in order to reduce the residual amount of water and oxygen in the refrigerant circuit of the air conditioner, evacuation is performed at the time of construction. In the evacuation, after connecting the outdoor unit and the indoor unit of the air conditioner with piping, the pressure inside the piping is set to a predetermined value close to vacuum or less. By vacuuming, water and oxygen in the refrigerant circuit are discharged to the outside, and the residual amount of water and oxygen in the refrigerant circuit is reduced. The remaining amount of water and oxygen in the refrigerant circuit after vacuuming is proportional to the volume of the refrigerant circuit. That is, the larger the volume of the refrigerant circuit, the larger the remaining amount of water and oxygen. The refrigerant that has reacted with water or oxygen is decomposed. The refrigerant is decomposed to generate an acid. The generated acid corrodes the metal member forming the refrigerant circuit. Corrosion of the metal members promotes wear of the sliding parts of the compressor, which significantly reduces the reliability of the air conditioner.

  On the other hand, there has been proposed a refrigeration cycle device in which the surface of a metal member forming a refrigerant circuit is covered with a coating layer to prevent the acid from coming into contact with the metal member (for example, Patent Document 1). In patent document 1, a specific component adheres to a metal surface to form a coating layer. Certain components are added to the refrigerating machine oil. However, adding additives to the refrigerating machine oil for all models results in high cost.

JP, 2010-230243, A

  The present invention solves the problems described above, and it is an object of the present invention to provide a refrigeration cycle apparatus that prevents corrosion of metal members of a refrigerant circuit at low cost.

The refrigeration cycle apparatus of the present invention achieves the above object, and includes a "refrigerant having a carbon-carbon bond other than a single bond as a carbon-carbon bond", and "a halogen group element having an atomic weight exceeding 10 times that of carbon. A mixed refrigerant containing 20% by weight or more of a low GWP refrigerant containing at least one of a "refrigerant having a single bond with carbon" and a "refrigerant having an ether bond", and a refrigerant circuit in which refrigerating machine oil circulates In a refrigeration cycle apparatus, which has a connection pipe forming the refrigerant circuit and has an internal surface area of the connection pipe of 0.6 m ² or more, nickel is used as a material of the metal member forming the refrigerant circuit. It is characterized by using a material not containing.

  According to the present invention, it is possible to provide a refrigeration cycle device that prevents corrosion of a metal member of a refrigerant circuit at low cost.

FIG. 1 is a refrigerant circuit diagram showing an air conditioner of an embodiment. FIG. 2 is a cross-sectional view showing the rotary compressor of the embodiment. FIG. 3 is a table showing the relationship between the residual water content in the refrigerant circuit of the embodiment and the surface area inside the pipe.

  Hereinafter, an air conditioner as an embodiment of the refrigeration cycle device disclosed in the present application will be described in detail with reference to the drawings. The air conditioner disclosed in the present application is not limited to the embodiments described below.

[Configuration of air conditioner]
FIG. 1 is a refrigerant circuit diagram showing an air conditioner of an embodiment. As shown in FIG. 1, the air conditioner 1 is a product type called a single model, which includes one outdoor unit 2 and one indoor unit 5. Although detailed description is omitted, in addition to the single model, there are a multi-model and a building-multi model in which a plurality of indoor units are connected to one outdoor unit. The outdoor unit 2 and the indoor unit 5 are connected by a liquid pipe 6a and a gas pipe 6b to form a refrigerant circuit 1a in which a refrigerant circulates. The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, a throttle device 24, a liquid side closing valve 61, a gas side closing valve 62, and an outdoor unit controller 200.

  The compressor 21 is controlled by the outdoor unit controller 200. As a result, the refrigerant supplied via the suction pipe 42 and the four-way valve 22 is compressed. The compressed refrigerant is supplied to the four-way valve 22 via the discharge pipe 41.

  The four-way valve 22 is connected to the discharge pipe 41 and the suction pipe 42, is connected to the outdoor heat exchanger 23 via the refrigerant pipe 43, and is connected to the indoor unit 5 via the refrigerant pipe 44 and the gas side closing valve 62. ing. The indoor unit 5 and the outdoor heat exchanger 23 are connected via a liquid side closing valve 61 and a refrigerant pipe 45. The four-way valve 22 is controlled by the outdoor unit controller 200 to switch the air conditioner 1 to either the heating mode or the cooling mode. When switched to the cooling mode, the four-way valve 22 supplies the refrigerant discharged from the compressor 21 via the discharge pipe 41 to the outdoor heat exchanger 23, and sucks the refrigerant flowing out of the indoor unit 5 into the compressor 21. Supply via 42. When switched to the heating mode, the four-way valve 22 supplies the refrigerant discharged from the compressor 21 via the discharge pipe 41 to the indoor unit 5, and the refrigerant flowing out from the outdoor heat exchanger 23 is sucked into the compressor 21. Supply via 42.

  The outdoor heat exchanger 23 is connected to the expansion device 24 via a refrigerant pipe 45. An outdoor fan 27 is arranged near the outdoor heat exchanger 23. The outdoor fan 27 takes in outside air into the inside of the outdoor unit 2 by being rotated by a fan motor (not shown), and discharges the outside air that has exchanged heat with the refrigerant by the outdoor heat exchanger 23 to the outside of the outdoor unit 2. .. In the cooling mode, the outdoor heat exchanger 23 causes the refrigerant supplied from the four-way valve 22 and the outside air taken into the outdoor unit 2 to exchange heat with each other, and supplies the heat-exchanged refrigerant to the expansion device 24. To do. In the heating mode, the outdoor heat exchanger 23 causes the refrigerant supplied from the expansion device 24 and the outside air taken into the outdoor unit 2 to exchange heat, and supplies the heat-exchanged refrigerant to the four-way valve 22. To do.

  The expansion device 24 is connected to the indoor unit 5 via a refrigerant pipe 45 and a liquid side closing valve 6a. In the cooling mode, the expansion device 24 decompresses the refrigerant supplied from the outdoor heat exchanger 23 by adiabatic expansion, and supplies the low temperature and low pressure two-phase refrigerant to the indoor unit 5.

  The indoor unit 5 includes an indoor heat exchanger 51, an indoor fan 55, and an indoor unit controller 500. The indoor fan 55 is arranged in the vicinity of the indoor heat exchanger 51, and is rotated by a fan motor (not shown) to take in indoor air into the indoor unit 5 and the indoor heat exchanger 51 causes the refrigerant to flow. The indoor air that has exchanged heat with is released into the room. The indoor heat exchanger 51 is connected to the four-way valve 22 via the gas side closing valve 6b and the refrigerant pipe 44, and to the expansion device 24 of the outdoor unit 2 via the refrigerant pipe 45, respectively. The indoor heat exchanger 51 functions as an evaporator when the air conditioning apparatus 1 is switched to the cooling mode, and functions as a condenser when the air conditioning apparatus 1 is switched to the heating mode. That is, the indoor heat exchanger 51 exchanges heat between the low-temperature low-pressure two-phase refrigerant supplied from the expansion device 24 and the indoor air taken into the indoor unit 5 in the cooling mode, and The heat-exchanged indoor air is discharged into the room, and the heat-exchanged refrigerant is supplied to the four-way valve 22. In the heating mode, the indoor heat exchanger 51 exchanges heat between the refrigerant supplied from the four-way valve 22 and the indoor air taken into the indoor unit 5, and transfers the indoor air that has undergone the heat exchange to the room. The refrigerant that has been discharged and has undergone heat exchange is supplied to the expansion device 24.

[Compressor]
FIG. 2 is a cross-sectional view showing the compressor 21 of the embodiment. As shown in FIG. 2, the compressor 21 is a high-pressure dome type rotary compressor including a compressor housing 10, a shaft 15, a motor unit 11, and a compressor unit 12. The compressor housing 10 is formed in a substantially cylindrical shape, and forms an internal space 16 that is sealed from the environment in which the compressor 21 is installed. The internal space 16 is formed in a substantially cylindrical shape. The compressor housing 10 is arranged so that the axes of the cylinders of the internal space 16 are parallel to the vertical direction when the compressor housing 10 is placed vertically on a horizontal plane. The compressor casing 10 has an oil sump 17 formed in a lower portion of the internal space 16. Refrigerating machine oil that lubricates the compressor unit 12 is stored in the oil sump 17. In the compressor housing 10, the internal space 16 is connected to the suction pipe 42 and the discharge pipe 41. The suction pipe 42 includes a first suction pipe 421 and a second suction pipe 422. The shaft 15 is formed in a rod shape and is arranged in the internal space 16 of the compressor housing 10. The shaft 15 is supported by the compressor housing 10 so as to be rotatable about a rotation axis that is parallel to the axis of the cylinder formed by the internal space 16.

[Motor part]
The motor unit 11 is arranged in the upper part of the internal space 16. The motor unit 11 includes a rotor 112 and a stator 111. The rotor 112 is formed in a substantially columnar shape and is fixed to the shaft 15. The stator 111 is formed in a substantially cylindrical shape and is fixed to the compressor housing 10. The stator 111 is arranged so as to surround the rotor 112 and is fixed to the compressor housing 10. The stator 111 includes a stator core 113 and a plurality of windings 114. The plurality of winding wires 114 are respectively wound around a plurality of teeth portions formed on the stator core 113. Further, the shaft 15 has its upper end and lower end slidably fixed by bearings 140, respectively. The rotor 112 is optionally provided with a metal balance weight 115.

  The motor unit 11 is configured by a brushless DC motor and is driven by reluctance torque. Further, the permanent magnet of the rotor 112 is composed of a rare earth magnet or a ferrite magnet.

[Compressor section]
The compressor unit 12 includes a first compression unit 12S and a second compression unit 12T. The first compression unit 12S includes a first cylinder 121S, a first annular piston 125S, and a first vane (not shown). The first cylinder 121S forms a first cylinder chamber 130S. The first annular piston 125S is arranged in the first cylinder chamber 130S and fixed to the shaft 15. The first vane is movably supported by the first cylinder chamber 130S, and partitions the working chamber formed between the first cylinder 121S and the first annular piston 125S into a suction chamber and a compression chamber. The suction chamber is a space defined by the first cylinder 121S, the first annular piston 125S, and the first vane, and is connected to the first suction pipe 421 of the suction pipe 42. The compression chamber is a space defined by the first cylinder 121S, the first annular piston 125S, and the first vane, and is connected to the internal space 16 of the compressor housing 10. The volume of the suction chamber expands due to the rotation of the shaft 15, and after the suction process of expanding to a predetermined volume (excluded volume), the suction chamber transitions to the compression chamber. The volume of the compression chamber is reduced by the rotation of the shaft 15, and after the volume is reduced to a predetermined volume, the compression chamber transitions to the suction chamber.

  The second compression section 12T is formed in substantially the same manner as the first compression section 12S, and is arranged above the first compression section 12S. The second compression unit 12T includes a second cylinder 121T and a second annular piston 125T, and includes a second vane (not shown). The second cylinder 121T forms a second cylinder chamber 130T. The second annular piston 125T is arranged in the second cylinder chamber 130T and is fixed to the shaft 15 so that a phase difference of 180 ° with the second annular piston 125T is formed with respect to the shaft 15. The second vane is movably supported in the second cylinder chamber 130T, and partitions the working chamber formed between the second cylinder 121T and the second annular piston 125T into a suction chamber and a compression chamber. The suction chamber is a space defined by the second cylinder 121T, the second annular piston 125T, and the second vane, and is connected to the second suction pipe 422 of the suction pipe 42. The compression chamber is a space defined by the second cylinder 121T, the second annular piston 125T, and the second vane, and is connected to the internal space 16 of the compressor housing 10. The suction chamber expands in volume as the shaft 15 rotates, and after expanding to a predetermined volume, transitions to a compression chamber. The volume of the compression chamber is reduced by the rotation of the shaft 15, and after the volume is reduced to a predetermined volume, the compression chamber transitions to the suction chamber.

[Refrigerant]
The air-conditioning apparatus 1 includes a "refrigerant having a carbon-carbon bond other than a single bond as a bond between carbon atoms", a "refrigerant having a single bond of a halogen group element and carbon having an atomic weight exceeding 10 times that of carbon". A mixed refrigerant containing 20 wt% or more of a low GWP refrigerant containing at least one of "refrigerants having an ether bond" is used as a working fluid. Examples of the refrigerant having a carbon-carbon bond other than a single bond between carbon atoms include an HFO refrigerant having a double bond between carbon atoms and trifluoropropyne having a triple bond between carbon atoms. Further, there is trifluoromethane iodide as a refrigerant having a single bond between a halogen group element having an atomic weight exceeding 10 times that of carbon and carbon, and HFE-143m as a refrigerant having an ether bond (also referred to as HFE refrigerant). Is mentioned. These refrigerants have low stability in the refrigeration cycle apparatus. Further, these refrigerants have low stability in the atmosphere and tend to have a relatively low GWP. Instead, the refrigerant has a relatively low pressure. When a refrigerant having a low pressure is used as a working fluid of an air conditioner, the volumetric capacity (unit is kJ / m ³ ) which is one of the indexes of the refrigerant performance becomes low. Therefore, when used as a working fluid of an air conditioner, it is considered to be mixed with another refrigerant having high refrigerant performance (for example, R32). In this example, since the refrigerant having a carbon-carbon bond other than a single bond between carbon atoms has a low GWP, that is, the environmental load is small, the carbon-carbon bond other than a single bond is used. A mixed refrigerant containing at least 20% by weight of a refrigerant having a carbon-carbon bond is used as a working fluid.

Among refrigerants having a single bond as a bond between carbon atoms, it has a track record of being used in air conditioners, is a non-combustible, non-toxic refrigerant with an ozone depletion potential (ODP) of 0, and has the lowest GWP. The single refrigerant is R134a (GWP: 1430). The "low GWP refrigerant" of this embodiment has a lower GWP than that of R134a.
The refrigerant having a single bond between a halogen group element and carbon is a chlorofluorocarbon typified by R12 having a bond between chlorine (atomic weight: 35.5) and carbon, and a bond between bromine (atomic weight: 79.9) and carbon. There is a halon 1301 having, and iodine (trifluoromethane) having a bond between iodine (atomic weight: 126.9) and carbon.
R12 containing chlorine has a GWP of 10900. Halon 1301 containing bromine has a GWP of 7140. Trifluoromethane iodide containing iodine has a GWP of 1 or less. As can be seen from this, the refrigerant having a single bond between a halogen group element and carbon has a lower GWP as the atomic weight of the halogen group element is smaller. In addition, the GWP of each of the above-mentioned refrigerants is "Order for the rational use of fluorocarbons and proper management of the law, Article 1, paragraph 3 of the Ordinance for Enforcement, and order regarding reporting of leakage amounts of fluorocarbons, etc. In accordance with the regulations of the International Organization for Standardization, the ratio of carbon dioxide to the extent that causes global warming for each type specified by the Minister of the Environment and the Minister of Economy, Trade and Industry and for each type of CFCs The values are those specified by the coefficient set by the Minister of the Environment and the Minister of Economy, Trade and Industry based on the internationally recognized knowledge as a numerical value (FCN GWP notification) (2016 Ministry of Economy, Trade and Industry / Ministry of the Environment Notification No. 2). ..

The relationship between the atomic weight of the halogen group element and the GWP of a typical refrigerant containing the halogen group element can be expressed by the following formula.
(Atomic weight) = − 4.0 × 10 ⁻⁸ × (GWP) ² −3.0 × 10 ⁻⁴ × (GWP) +10.58
From the above formula, in order to make GWP lower than R134a (GWP: 1430), a refrigerant having a single bond between a halogen group element and carbon having an atomic weight exceeding 10 times that of carbon (atomic weight: 12) is required. I know it is necessary.

  Refrigerants having carbon-carbon bonds other than single bonds between carbon atoms, "refrigerants having a single bond between a halogen group element having an atomic weight exceeding 10 times that of carbon and carbon" and "refrigerants having an ether bond" are chemical. Unstable. Specifically, it easily reacts with water and oxygen. Therefore, the air conditioning apparatus 1 performs evacuation before the mixed refrigerant is filled after the installation. Specifically, the air conditioner 1 is attached by connecting an outdoor unit 2 installed outdoors and an indoor unit 5 installed indoors with a liquid pipe 6a and a gas pipe 6b. The attached air conditioner 1 performs evacuation to remove water and oxygen remaining inside the liquid pipe 6a and the gas pipe 6b.

  The evacuation is performed by connecting, for example, a vacuum pump (not shown) of the air conditioner 1 to the gas side closing valve 62. The evacuation is performed until the pressure in the refrigerant circuit 1a becomes equal to or lower than a predetermined pressure (for example, -0.1 MPaG).

  By vacuuming, water and oxygen in the refrigerant circuit 1a can be discharged to the outside. However, water and oxygen are not completely discharged and remain in the refrigerant circuit 1a. The remaining amount of water and oxygen in the refrigerant circuit 1a after the evacuation is performed is proportional to the volume of the refrigerant circuit 1a. Therefore, in an air conditioner having a large capacity of the refrigerant circuit 1a, the amount of water and oxygen remaining in the refrigerant circuit 1a increases. The refrigerant that has reacted with water and oxygen remaining in the refrigerant circuit 1a is decomposed to generate an acid. The generated acid corrodes the metal member forming the refrigerant circuit 1a. In particular, when the sliding portion (for example, the annular piston, the vane, etc.) of the compressor 21 is corroded, the reliability of the air conditioner 1 is significantly reduced.

  In the present embodiment, based on the inner surface area of the pipe of the refrigerant circuit 1a of the air conditioner 1, it is selected whether or not nickel, which has a strong acid reactivity, is used as the material of the metal member forming the refrigerant circuit 1a. Nickel is used as the material of the metal member forming the refrigerant circuit 1a only for models in which the amount of water exceeds a predetermined amount (the amount of acid corrosion does not impair the reliability of the air conditioner 1). Not in. This can prevent corrosion of the metal member forming the refrigerant circuit 1a at low cost. In addition, the metal member in the present embodiment refers to a metal member that is directly exposed to the refrigerant circulating therein, among the members forming the refrigerant circuit 1a. For example, it is a member used for the first compression unit 12S (for example, the first annular piston 125S) and the second compression unit 12T (for example, the second annular piston 125T) of the compressor 21.

  FIG. 3 is a schematic diagram illustrating the relationship between the residual water amount in the refrigerant circuit 1a and the surface area of the inside of the pipe of the refrigerant circuit 1a, and the table is rotated 90 degrees to the left.

  In FIG. 3, six models having different capabilities (described in the third column from the right end) are described as an example. FIG. 3 shows the residual water content in the refrigerant circuit 1a and the surface area of the inside of the refrigerant circuit 1a for each of the six models.

The rightmost column in FIG. 3 shows an estimated value (unit: g) of the residual water amount indicating the amount of residual water in the refrigerant circuit 1a after evacuation. The residual water content is estimated from the surface area in the tube (unit: m ² ). Specifically, the remaining amount of water is estimated from the ratio of water contained in the air under the environment of a predetermined condition (temperature, humidity).

  The pipe internal surface area is shown in the second column from the right end in FIG. 3, and the value shown here is the pipe internal surface area of the connection pipe excluding the pipe internal surface areas of the outdoor heat exchanger 23 and the indoor heat exchanger 51. .. The surface area inside the pipe is a value that is assumed when the length of the connecting pipe (the liquid pipe 6a and the gas pipe 6b) is the maximum pipe length (unit is m). The inner surface area of the pipe is calculated by assuming the inner diameter (unit: mm) of the connecting pipe (the liquid pipe 6a and the gas pipe 6b) described in the third column from the left end in FIG. The refrigerant circuit 1a having a large internal surface area has a large internal volume. In an air conditioner with a large capacity of the refrigerant circuit 1a, the amount of water and oxygen remaining in the refrigerant circuit 1a increases. Therefore, the refrigerant circuit 1a having a large surface area inside the pipe has a large amount of residual water.

  The pipe internal volume is described in the third column from the right end in FIG. 3, and the value shown here is the pipe internal volume of the connection pipe excluding the pipe internal volumes of the outdoor heat exchanger 23 and the indoor heat exchanger 51. .. Further, the pipe internal volume is a value assuming a case where the length of the connecting pipe (the liquid pipe 6a and the gas pipe 6b) is the maximum pipe length (unit is m). The internal volume of the pipe is calculated assuming the inner diameter (unit: mm) of the connecting pipe (the liquid pipe 6a and the gas pipe 6b) described in the third column from the left end in FIG.

  The maximum pipe length is described in the second column from the left end in FIG. 3 and is a value determined for each model. The maximum pipe length indicates the maximum length of the connection pipe that can be tolerated by the model. The two types of building multi show the maximum pipe length of the main pipe (merging pipe before branching to the branch pipe connected to each indoor unit), and it becomes even longer if the branch pipe is included.

As a result of verification by the applicant, when the residual water content is 0.5 g or more in any of the models, the generated acid corrodes the metal member to a large scale. In FIG. 3, all the product forms correspond to models having the above “water content” of 0.5 g or more. Therefore, for these models, it is necessary not to use a material (a material containing nickel) that promotes the generation of acid as a material of the metal member forming the refrigerant circuit 1a in preparation for the case where acid is generated. On the other hand, a model in which the pipe surface area is less than 0.6 m ² when the length of the connecting pipe is the maximum pipe length (for example, a small air conditioner including an integrated air conditioner such as a “wind type”) has a residual moisture amount. The amount is less than 0.5 g, and the amount of corrosion due to acid does not impair the reliability of the air conditioning apparatus 1. Therefore, even if a material that promotes the generation of acid is used as the material of the metal member forming the refrigerant circuit 1a, the effect of the acid on the reliability of the air conditioning apparatus 1 is small.

On the other hand, in the model in which the pipe surface area is less than 0.6 m ² when the length of the connecting pipe is the maximum pipe length, nickel is used as the material of the metal member forming the refrigerant circuit 1a without considering the above restrictions. Materials to be included can be selected. Materials that do not contain nickel include Mo-Cr steel and Cr steel. Compared with Mo-Ni-Cr steel that uses nickel, when a material that does not contain nickel is used, the strength decreases, so it is necessary to perform processing such as sub-zero treatment to improve the strength. High-strength processing will be costly for all models, but models with an internal pipe surface area of less than 0.6 m ² when the length of the connecting pipe is the maximum are as described above. A material containing nickel can be selected as the material of the metal member forming the refrigerant circuit 1a without considering restrictions. Therefore, it is possible to implement at low cost a measure to reduce reliability due to corrosion of the metal member forming the refrigerant circuit 1a.

On the other hand, in a model in which the pipe surface area is less than 0.6 m ² when the length of the connecting pipe is the maximum pipe length, the material of the metal member forming the refrigerant circuit 1a can be selected without considering the above restrictions. .. Therefore, it is possible to implement at low cost a measure to reduce reliability due to corrosion of the metal member forming the refrigerant circuit 1a.

  In the present embodiment, whether or not to use a material containing nickel as the material of the metal member forming the refrigerant circuit 1a is selected based on the internal surface area of the pipe of the refrigerant circuit 1a of the air conditioner 1. Whether or not to use a material containing nickel may be selected based on the internal volume of the refrigerant circuit 1a of the air conditioner 1. The remaining amount of water or oxygen in the refrigerant circuit 1a after the evacuation is performed is proportional to the size of the pipe internal volume of the refrigerant circuit 1a. Specifically, the larger the internal volume of the tube, the larger the residual amount of water. In this case, in a model having a pipe internal volume of 1000 cc or more, the material of the metal member forming the refrigerant circuit 1a is a material containing no nickel.

1 Air Conditioner 1a Refrigerant Circuit 2 Outdoor Unit 5 Indoor Unit 21 Compressor 22 Four-way Valve 23 Outdoor Heat Exchanger 24 Throttling Device 27 Outdoor Fan 41 Discharge Pipe 42 Intake Pipe 43 Refrigerant Piping 44 Refrigerant Piping 45 Refrigerant Piping 51 Indoor Heat Exchanger 55 Indoor fan 6a Liquid pipe 6b Gas pipe 61 Liquid side closing valve 62 Gas side closing valve 200 Outdoor unit control unit 500 Indoor unit control unit

The refrigeration cycle apparatus of the present invention achieves the above object, and includes a "refrigerant having a carbon-carbon bond other than a single bond as a carbon-carbon bond", and "a halogen group element having an atomic weight exceeding 10 times that of carbon. A mixed refrigerant containing 20% by weight or more of a low GWP refrigerant containing at least one of a "refrigerant having a single bond with carbon" and a "refrigerant having an ether bond", and a refrigerant circuit in which refrigerating machine oil circulates A refrigeration cycle apparatus, which has a connection pipe forming the refrigerant circuit, has an inner surface area of 0.6 m ² or more of the connection pipe, and is directly connected to the mixed refrigerant in the connection pipe. As a material of the metal member to be exposed, a material obtained by subjecting a metal material containing no nickel to a subzero treatment is used.

Claims (2)

At least one of a refrigerant having a carbon-carbon bond other than a single bond as a bond between carbon atoms, a refrigerant having a single bond between a halogen group element having an atomic weight exceeding 10 times that of carbon and carbon and an ether bond. A mixed refrigerant containing 20% by weight or more of a low GWP refrigerant containing
A refrigeration cycle device including a refrigerant circuit in which refrigeration oil circulates,
In the case where the connection pipe forming the refrigerant circuit is provided and the internal surface area of the connection pipe is 0.6 m ² or more, a material containing no nickel is used as the material of the metal member forming the refrigerant circuit. Refrigeration cycle device characterized by. When the inner surface area of the pipe when the length of the connecting pipe is the maximum pipe length is 0.6 m ² or more, a material containing no nickel is used as the material of the metal member forming the refrigerant circuit. The refrigeration cycle apparatus according to claim 1.

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