Refrigeration cycle device

Abstract

Provided is a refrigeration cycle device in which the resistance to vibration of a refrigerant pipe is high and the manufacturing cost is reduced. An outdoor unit of a refrigeration cycle device provided with a compressor, a heat source-side heat exchanger, a pressure reducer, a gas-side blocking valve, and a liquid-side blocking valve is provided with: a first metal member disposed at least in a gas-side refrigerant circuit connecting the gas-side blocking valve and the heat source-side heat exchanger via the compressor; a second metal member disposed at least in a liquid-side refrigerant circuit connecting the heat source-side heat exchanger and the liquid-side blocking valve via a pressure reducer; a first copper pipe joined to the first metal member; and a second copper pipe joined to the second metal member, the first metal member and the second metal member being made of iron, iron alloy, or stainless steel, the first copper pipe being made of a copper alloy containing an alloying element, and the second copper pipe being made of copper not containing an alloying element, or being made of a copper alloy having a lower alloying element content than the first copper pipe.

Description

Technical Field

[0001] This invention relates to a refrigeration cycle apparatus having a refrigerant piping assembly having copper refrigerant piping joined to ferrous refrigerant piping made of stainless steel or other iron-based materials, and particularly to the outdoor unit of the refrigeration cycle apparatus. Background Technology

[0002] Air conditioning equipment, refrigeration equipment, and cold storage equipment all possess a refrigerant circuit that circulates refrigerant to perform a refrigeration cycle. Within this refrigerant circuit, components such as compressors, condensers, pressure reducers, and evaporators are connected via refrigerant piping. Traditionally, refrigerant piping was made of copper, such as deoxidized phosphorus copper. Furthermore, components of heat exchangers, such as heat transfer tubes, oil separators, and valves, are also often made of copper.

[0003] Patent document 1 describes a copper alloy tube for heat exchangers that exhibits superior bending workability and heat resistance compared to existing phosphorus-deoxidized copper. This copper alloy tube for heat exchangers actively incorporates elements such as Co, Sn, Zn, Ni, and P. The improved mechanical properties are achieved through precipitation strengthening and solid solution strengthening induced by the addition of these alloying elements.

[0004] Existing technical documents

[0005] Patent Document 1: Patent No. 5111922

[0006] In recent years, the price of copper has risen, increasing the material costs of refrigerant piping and equipment that form the refrigerant circuit. Therefore, costs can be reduced by changing the materials used in refrigerant piping and equipment that form the refrigerant circuit from copper-based materials such as phosphorus deoxidized copper to iron-based materials such as stainless steel.

[0007] However, there are several obstacles in terms of performance and construction to completely converting the materials of refrigerant piping and equipment that form the refrigerant circuit to ferrous metals. Therefore, it is currently envisioned that copper-based refrigerant piping and equipment used in the past coexist with stainless steel and other ferrous refrigerant piping and equipment.

[0008] In situations where stainless steel and other ferrous refrigerant piping and equipment coexist, it is necessary to properly fuse these dissimilar metals together. However, it is known that fusing copper with stainless steel is not easy due to differences in physical properties and the presence of oxide films. It is desirable that these fusions be performed in an environment-controlled furnace, not in the atmosphere. On the other hand, regarding copper components, it is desirable that they can be easily fused together using existing equipment and in the field.

[0009] To address this problem, a solution is proposed that connect the equipment forming the refrigerant circuit of a refrigeration cycle unit to each other using refrigerant piping assemblies. A refrigerant piping assembly is a component consisting of copper pipes (made of copper or copper alloys) joined to ferrous refrigerant piping. The refrigerant piping assembly is obtained by brazing the ends of the copper pipes to the ends of the ferrous refrigerant piping in a furnace. If the refrigerant piping assembly is pre-manufactured under suitable conditions and then connected to existing equipment, a low-cost refrigerant circuit with appropriate connections to the ferrous refrigerant piping can be easily formed.

[0010] However, even with such countermeasures, there are still issues regarding the strength of the copper tubing in the refrigerant piping assembly. In refrigeration systems, the copper tubing is affected by vibrations during operation, particularly near the compressor and valves that switch between components. If the copper tubing is weak, fatigue failure may occur. Repeated stress caused by vibration can lead to the refrigerant piping assembly detaching from the equipment or the copper tubing breaking.

[0011] In particular, the refrigerant piping assemblies are formed by furnace brazing at high temperatures of around 800–1200°C for an extended period of 20–30 minutes, resulting in significant thermal effects on the copper tubing. This leads to a tendency for grain coarsening and a decrease in tensile and fatigue strength. Using existing phosphorus-deoxidized copper supplied for furnace brazing near compressors that generate continuous vibrations or valves that produce intermittent vibrations during switching further increases the risk of fatigue failure. Summary of the Invention

[0012] Therefore, the object of the present invention is to provide a refrigeration cycle device with refrigerant piping that has high resistance to vibration and reduces manufacturing costs.

[0013] To address the aforementioned issues, the outdoor unit of the refrigeration cycle apparatus of the present invention includes a compressor, a heat exchanger on the heat source side, a pressure reducer, a gas-side preventive valve, and a liquid-side preventive valve. It further includes: a first metal component disposed at least in a gas-side refrigerant circuit that connects the gas-side preventive valve and the heat exchanger on the heat source side via the compressor; a second metal component disposed at least in a liquid-side refrigerant circuit that connects the heat exchanger on the heat source side via the pressure reducer; a first copper tube joined to the first metal component; and a second copper tube joined to the second metal component. The first and second metal components are made of iron, an iron alloy, or stainless steel. The first copper tube is a copper alloy containing alloying elements, and the second copper tube is made of copper without the alloying elements, or a copper alloy with a lower content of the alloying elements than the first copper tube.

[0014] The effects of this invention are as follows.

[0015] According to the present invention, a refrigeration cycle device can be provided, wherein the refrigerant piping has high resistance to vibration and reduces manufacturing costs. Attached Figure Description

[0016] Figure 1 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle apparatus of the first embodiment.

[0017] Figure 2 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle device of the second embodiment.

[0018] Figure 3 This is a diagram showing the refrigerant circuit of the refrigeration cycle device according to the third embodiment.

[0019] Figure 4 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle apparatus of the fourth embodiment.

[0020] Figure 5 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle apparatus of the fifth embodiment.

[0021] Figure 6 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle apparatus of the sixth embodiment.

[0022] Figure 7 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle apparatus of the seventh embodiment.

[0023] Figure 8 This is a diagram showing the refrigerant circuit provided in the refrigeration cycle apparatus of the eighth embodiment.

[0024] Figure 9 This is a graph showing the results of measurements on the fatigue characteristics of copper-based refrigerant piping.

[0025] Figure 10 This diagram shows an example of the connection between an iron-based refrigerant pipe and a copper pipe.

[0026] In the diagram: 1—Air conditioner, 2—Compressor, 3—Four-way valve, 3a—Iron-based four-way valve, 4—Outdoor heat exchanger, 5a—Outdoor expansion valve, 5b—Indoor expansion valve, 6—Indoor heat exchanger, 7—Energy storage unit, 8—Oil separator, 8a—Iron-based oil separator, 10—Refrigerant circuit, 11—Iron-based first refrigerant piping, 12—Iron-based second refrigerant piping, 13—First copper pipe, 14—Second copper pipe, 15—Copper-based refrigerant piping, 16—Outdoor air supply fan, 17—Indoor air supply fan, 18—Gas-side check valve, 19—Liquid-side check valve, 20—Copper components. Detailed Implementation

[0027] The following describes a refrigeration cycle apparatus according to one embodiment of the present invention. Furthermore, in the following figures, common structures are labeled with the same symbols, and repeated descriptions are omitted.

[0028] <First Implementation>

[0029] Figure 1 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the first embodiment of the present invention. Figure 1 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 1 As shown, the air conditioner 1 includes an outdoor unit 100 installed outdoors and an indoor unit 200 installed on a wall or other structure indoors.

[0030] Air conditioner 1 is a device that adjusts the temperature and humidity of a space by blowing out heated air, cooled air, or dehumidified air. Refrigerant circulates between the outdoor unit 100 and the indoor unit 200 through refrigerant pipes. Heat exchange occurs between the refrigerant and the outside air in the outdoor unit 100. Heat exchange occurs between the refrigerant and the indoor air in the indoor unit 200. The indoor unit 200 draws in air from the room, exchanges heat with the refrigerant, and then blows it out into the room to adjust the indoor temperature and humidity.

[0031] like Figure 1 As shown, the air conditioner 1 includes a refrigerant circuit 10 that constitutes a heat pump. The refrigerant circuit 10 performs refrigeration cycles for cooling, heating, and dehumidification operations. The refrigerant circuit 10 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an outdoor expansion valve 5a, an indoor expansion valve 5b, an indoor heat exchanger 6, an energy storage unit 7, and an oil separator 8.

[0032] These devices are interconnected via refrigerant piping that allows refrigerant to circulate. In the outdoor unit 100 and between it and the indoor unit 200, a gas pipe serving as a refrigerant piping is connected via a gas-side shut-off valve 18, and a liquid pipe serving as a refrigerant piping is connected via a liquid-side shut-off valve 19. Through these devices and refrigerant piping, a closed-loop refrigerant circuit 10 for refrigerant circulation is formed between the outdoor unit 100 and the indoor unit 200.

[0033] Refrigerant is sealed in refrigerant circuit 10. The refrigerant circulates in refrigerant circuit 10, exchanging heat with indoor and outdoor air for cooling, heating, and dehumidification operations. The outdoor unit 100 houses the compressor 2, four-way valve 3, outdoor heat exchanger 4, outdoor expansion valve 5a, energy storage tank 7, oil separator 8, and outdoor fan 16. The indoor unit 200 houses the indoor expansion valve 5b, indoor heat exchanger 6, and indoor fan 17.

[0034] Compressor 2 is a device for compressing refrigerant. It draws in low-pressure gaseous refrigerant, adiabatically compresses it, and discharges high-pressure gaseous refrigerant. Compressor 2 can also be a structure in which the refrigerant circulation volume can be variably controlled by a converter. Compressor 2 can be a hermetic electric compressor of appropriate forms such as scroll, single-rotary, double-rotary, oscillating, piston, screw, or centrifugal. However, scroll or double-rotary compressors are preferred for minimizing vibration during operation.

[0035] The four-way valve 3 has a valve core that switches the connection of the flow paths between the four ports, changing the connection of the flow paths between the ports according to the operating mode, such as cooling operation or heating operation. The four-way valve 3 switches the circulation direction of the refrigerant discharged from the compressor 2 in the refrigerant circuit 10. Figure 2 In the diagram, solid arrows indicate the refrigerant circulation direction during cooling operation, while dashed arrows indicate the refrigerant circulation direction during heating operation.

[0036] The outdoor heat exchanger 4 is a heat exchanger that exchanges heat between the refrigerant and the outside air. It functions as a condenser during cooling operation and as an evaporator during heating operation. An outdoor fan 16 supplies outside air to the outdoor heat exchanger 4 to promote heat exchange. The outdoor fan 16 is, for example, a propeller fan. The outdoor expansion valve 5a is an electronically controlled valve with adjustable opening. During heating operation, it functions as a pressure reducer to expand the refrigerant. Additionally, in the absence of an indoor expansion valve 5b, the outdoor expansion valve 5a also functions as a pressure reducer to expand the refrigerant during cooling operation.

[0037] exist Figure 1 In this design, the outdoor heat exchanger 4 includes a main body 4a and a main pipe 4b. A distributor 4c is connected to the outdoor expansion valve 5a side of the main body 4a via a refrigerant piping. The main body 4a is a cross-finned tube heat exchanger, etc., that performs heat exchange in parallel flow, and includes multiple heat transfer tubes for refrigerant flow and multiple fins connected to the heat transfer tubes. The heat transfer tubes and fins are made of, for example, copper, copper alloys, aluminum alloys, etc.

[0038] The main pipe 4b is a device that divides a flow path into multiple flow paths or merges multiple flow paths into a single flow path according to the direction of refrigerant flow. On the four-way valve 3 side of the main pipe 4b, there is an opening forming a flow path, and a refrigerant pipe is connected between the main pipe 4b and the four-way valve 3. On the main body 4a side of the main pipe 4b, there is an opening forming multiple flow paths, and a heat transfer tube is connected to the main body 4a.

[0039] Distributor 4c is a device that combines multiple flow paths into one flow path or divides one flow path into multiple flow paths according to the refrigerant flow direction. On the main body 4a side of distributor 4c, there is an opening forming multiple flow paths, and a refrigerant pipe is connected between it and the heat transfer tube of the main body 4a. On the outdoor expansion valve 5a side of distributor 4c, there is an opening forming multiple flow paths, and a refrigerant pipe is connected between it and the outdoor expansion valve 5a.

[0040] The indoor expansion valve 5b functions as a pressure reducer to expand the refrigerant during cooling operation. The indoor heat exchanger 6 exchanges heat between the refrigerant and the indoor air; it functions as an evaporator during cooling operation and as a condenser during heating operation. The indoor fan 17 supplies air to the indoor heat exchanger 6 to promote heat exchange and blows the air, after heat exchange with the refrigerant, into the room. The indoor fan 17 is, for example, a cylindrical through-flow fan.

[0041] The energy storage unit 7 is a box-shaped device that separates the gaseous refrigerant from the liquid refrigerant, separating and storing the liquid refrigerant contained within the gaseous refrigerant. The energy storage unit 7 removes any unevaporated liquid refrigerant from the gaseous refrigerant on the suction side of the compressor 2. By removing the liquid refrigerant, liquid compression in the compressor 2, a major cause of noise and malfunctions, is prevented.

[0042] The oil separator 8 is a device for separating refrigerant from refrigeration oil. The oil separator 8 separates the refrigeration oil discharged from the compressor 2 along with the refrigerant. The refrigeration oil separated by the oil separator 8 does not circulate in the refrigerant circuit 10, but instead flows back to the compressor 2. By separating and returning the refrigeration oil, performance degradation caused by insufficient oil in the compressor 2 and mixing with the refrigerant circulating in the refrigerant circuit 10 can be prevented.

[0043] The cooling operation of air conditioner 1 proceeds as follows: High-temperature, high-pressure gaseous refrigerant, adiabatically compressed by compressor 2, is delivered to outdoor heat exchanger 4 via four-way valve 3. The high-temperature, high-pressure gaseous refrigerant condenses into liquid refrigerant through heat exchange with outside air in outdoor heat exchanger 4, which functions as a condenser. The liquid refrigerant then expands and depressurizes through indoor expansion valve 5b, becoming a low-temperature, low-pressure two-phase refrigerant containing a small amount of gaseous refrigerant.

[0044] Low-temperature, low-pressure gaseous-liquid two-phase refrigerant is sent to the indoor heat exchanger 6. The gaseous-liquid refrigerant evaporates into a low-temperature, low-pressure gaseous refrigerant through heat exchange with the indoor air in the indoor heat exchanger 6, which acts as an evaporator. The low-temperature, low-pressure gaseous refrigerant then passes through the four-way valve 3, where the liquid refrigerant is separated by the accumulator 7, and returns to the compressor 2. The indoor air loses heat through heat exchange with the refrigerant in the indoor heat exchanger 6, which also acts as an evaporator. This cycle is repeated to cool the room.

[0045] The heating operation of air conditioner 1 is carried out through a cycle that is the reverse of the cooling operation. The high-temperature, high-pressure gaseous refrigerant, adiabatically compressed and discharged by compressor 2, is sent to indoor heat exchanger 6 via a four-way valve 3. The high-temperature, high-pressure gaseous refrigerant is cooled by heat exchange with indoor air through indoor heat exchanger 6, which acts as a condenser, becoming liquid refrigerant. The liquid refrigerant is then depressurized by outdoor expansion valve 5a, becoming low-temperature, low-pressure liquid refrigerant.

[0046] Low-temperature, low-pressure liquid refrigerant is sent to outdoor heat exchanger 4. The low-temperature, low-pressure liquid refrigerant evaporates through heat exchange with outside air in outdoor heat exchanger 4, which functions as an evaporator, becoming low-temperature, low-pressure gaseous refrigerant. The low-temperature, low-pressure gaseous refrigerant then passes through four-way valve 3, where it is separated from the liquid refrigerant by accumulator 7, and returns to compressor 2. Indoor air is heated by heat exchange with the refrigerant in indoor heat exchanger 6, which functions as a condenser. This cycle is repeated to heat the indoor environment.

[0047] In the air conditioner 1 of this embodiment, the refrigerant circuit 10 can contain either a single refrigerant composed of a single refrigerant component or a mixed refrigerant composed of multiple refrigerant components. As the mixed refrigerant, either an azeotropic or non-azeotropic refrigerant mixture can be used. As the refrigerant, one or more of the following can be used: hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), CO2, hydrocarbons, ethers, fluoroethers, and fluoroolefins. Additives such as stabilizers that inhibit the decomposition of refrigerant components and overlap inhibitors that inhibit the overlap of refrigerant components can also be added to the refrigerant.

[0048] In the air conditioner 1 of this embodiment, a predetermined amount of refrigerant oil is injected into the compressor 2. During the operation of the compressor 2, the refrigerant oil is drawn from the oil reservoir and supplied to sliding parts such as the compression mechanism and bearings. The refrigerant oil is used for lubrication, cooling, and sealing of the sliding parts. Polyol ester oil, polyethylene ether oil, polyalkylene glycol oil, etc., can be used as the refrigerant oil. Additives such as acid scavengers, oxidation inhibitors, extreme pressure agents, stabilizers, defoamers, and metal deactivators can also be added to the refrigerant oil.

[0049] like Figure 1As shown, in the air conditioner 1 of this embodiment, at least a portion of the refrigerant circuit 10 is formed by an assembly. An assembly is a component made of ferrous metal with copper pipes attached to it. The metal component is a metal part that forms part of the refrigerant circuit 10, and consists of components such as refrigerant piping forming the refrigerant circuit 10, a part of the equipment performing the refrigeration cycle, such as the main body of the equipment, and piping connected to the connection portion of the equipment.

[0050] The component can be connected to more than one of the metal parts forming the refrigerant circuit 10. Figure 1 In this system, the connecting parts of the compressor 2, energy storage unit 7, and other equipment forming the refrigerant circuit 10 are constructed of copper components 20. The copper components 20 are integrally formed with the main body of the equipment and its connecting parts, and are made of copper alloys such as phosphorus-deoxidized copper. The components are joined with these metal parts using the same metal.

[0051] exist Figure 1 In this system, refrigerant piping assemblies 10a and 10b are included as components. Refrigerant piping assemblies 10a and 10b are refrigerant piping components consisting of iron-based refrigerant piping 11 and 12 connected to copper pipes 13 and 14. Refrigerant piping assemblies 10a and 10b function as refrigerant piping and can be connected to the refrigerant piping forming the refrigerant circuit 10 and the equipment forming the refrigerant circuit 10.

[0052] Refrigerant piping assemblies 10a and 10b are assembled component-like refrigerant piping units, formed using ferrous refrigerant piping 11 and 12 and copper pipes 13 and 14 as materials. The ferrous refrigerant piping 11 and 12 are joined to the copper pipes 13 and 14 by in-furnace brazing. In-furnace brazing can be performed, for example, in an environment where oxygen concentration, moisture content, hydrogen concentration, etc., are controlled.

[0053] For the iron-based refrigerant piping 11 and 12, iron pipes, ferroalloy pipes, or stainless steel pipes can be used. Examples of iron and ferroalloy pipes include steel, carbon steel, and alloy steel. Examples of stainless steel include austenitic stainless steels such as SUS304. Using iron-based refrigerant piping 11 and 12 can reduce raw material costs compared to copper-based piping.

[0054] For copper pipes 13 and 14, pipes made of copper or copper alloys can be used. Examples of copper include phosphorus-deoxidized copper, oxygen-free copper, and hard pitch copper. Examples of copper alloys, in addition to copper as the main component, can include alloys containing one or more of phosphorus (P), cobalt (Co), tin (Sn), zinc (Zn), nickel (Ni), zirconium (Zr), and iron (Fe). Using copper pipes 13 and 14 simplifies the connection to existing copper-based refrigerant piping and equipment forming the refrigerant circuit 10. Furthermore, it suppresses electrochemical corrosion caused by the bonding of dissimilar metals.

[0055] As copper alloys, examples of copper-based alloys containing Co, Sn, Zn, Ni, Zr, and Fe at a content of 0.01% by mass or more can be cited. Copper-based alloys containing phosphorus (P) at a content exceeding 0.040% by mass can also be used. Solid solution strengthened copper alloys with alloying elements dissolved in solid solution, and precipitation strengthened copper alloys with alloying elements precipitated above the solid solution limit, are also used. Using such copper alloys improves mechanical properties such as tensile strength and fatigue strength, thus reducing fatigue failure of copper tubes even when vibration occurs during equipment operation.

[0056] Refrigerant piping assemblies 10a and 10b can be joined to other refrigerant piping and equipment forming the refrigerant circuit 10, for example, by brazing in the atmosphere, flaring, or welding. During the assembly of the refrigerant circuit 10, the copper tubes 13 and 14 on the end sides of the refrigerant piping assemblies 10a and 10b, which are formed by furnace brazing, can be easily joined to existing copper-based refrigerant piping and equipment using conventional equipment. Furthermore, since heating of the copper tubes 13 and 14 in the furnace can be avoided, the decrease in strength caused by grain coarsening can be suppressed.

[0057] The refrigerant piping assemblies 10a and 10b can be formed by connecting the copper pipes 13 and 14 to one end of the iron-based refrigerant piping 11 and 12, or by connecting them to both ends of the iron-based refrigerant piping 11 and 12. However, when connecting the refrigerant piping assemblies 10a and 10b to copper-based refrigerant piping and equipment, it is preferable to pre-connect the copper pipes 13 and 14 to the corresponding ends of the refrigerant piping assemblies 10a and 10b.

[0058] exist Figure 1 In the middle, as refrigerant piping assemblies 10a and 10b, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b are connected to each other on the refrigerant circuit 10.

[0059] The first refrigerant piping assembly 10a is formed by joining a first refrigerant piping 11 made of iron, an iron alloy, or stainless steel to a first copper pipe 13 made of copper alloy. The first copper pipe 13 is formed of a copper alloy containing one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe, and more than 0.040% by mass of P. The first copper pipe 13 is a copper alloy refrigerant piping whose mechanical properties, such as tensile strength and fatigue strength, are improved through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements.

[0060] The first copper tube 13 can, for example, contain Co at a content of more than 0.01% by mass and less than 0.5% by mass, preferably more than 0.04% by mass and less than 0.2% by mass. It can contain Sn at a content of more than 0.01% by mass and less than 1.0% by mass, preferably more than 0.05% by mass and less than 0.8% by mass. It can contain Zn at a content of more than 0.01% by mass and less than 0.5%, preferably more than 0.02% by mass and less than 0.2% by mass. It can contain Ni at a content of more than 0.01% by mass and less than 1.0% by mass, preferably more than 0.02% by mass and less than 0.5% by mass. It can contain Zr at a content of more than 0.01% by mass and less than 0.5% by mass, preferably more than 0.04% by mass and less than 0.1% by mass. It can contain Fe at a content of more than 0.01% by mass and less than 5.0% by mass, preferably more than 1% by mass and less than 3.0% by mass.

[0061] The Cu content of the first copper tube 13 is preferably 95% by mass or more, more preferably 97% by mass or more, and even more preferably 99% by mass or more. The P content can be 0.015% by mass or more and 0.040% by mass or less, or it can exceed 0.040% by mass. The content of the alloying elements in the first copper tube 13 relative to the base metal as the main component is preferably lower than the content of the alloying elements in the iron-based first refrigerant piping 11 relative to the base metal as the main component.

[0062] The second refrigerant piping assembly 10b is formed by joining a second copper pipe 14, which is made of copper or a copper alloy, to a second refrigerant piping 12, which is made of iron, an iron alloy, or stainless steel. The second copper pipe 14 is formed of copper alloy that substantially does not contain one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, wherein the content of these alloying elements relative to the base metal as the main component is lower than that in the first copper pipe 13. The second copper pipe 14 can be formed of phosphorus-deoxidized copper, low-cost low-alloy copper with fewer alloying elements, etc.

[0063] exist Figure 1In this configuration, the refrigerant circuit 10 is formed by connecting a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), an outdoor expansion valve 5a (serving as a pressure reducer), an indoor expansion valve 5b, an indoor heat exchanger 6 (serving as a utilization-side heat exchanger), an energy storage tank 7, an oil separator 8, a gas-side shut-off valve 18, and a liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0064] In the gas-side refrigerant circuit 10A, the compressor 2 in the refrigerant circuit 10 is not connected to the outdoor heat exchanger 4, which serves as a heat source, via the outdoor expansion valve 5a, which acts as a pressure reducer. The gas-side refrigerant circuit 10A connects the gas-side stop valve 18 to the outdoor heat exchanger 4 via the compressor 2, etc. A first metal component, joined with a first copper pipe 13, is disposed in at least a portion of the gas-side refrigerant circuit 10A.

[0065] The liquid-side refrigerant circuit 10B connects the outdoor heat exchanger 4 to the liquid-side stop valve 19 via the outdoor expansion valve 5a, etc. A second metal component, connected to a second copper pipe 14, is disposed in at least a portion of the liquid-side refrigerant circuit 10B.

[0066] The gas-side refrigerant circuit 10C connects the indoor end of the gas-side refrigerant circuit 10A to the indoor end of the liquid-side refrigerant circuit 10B via an indoor heat exchanger 6, which serves as a utilization-side heat exchanger. The utilization-side refrigerant circuit 10C is a refrigerant circuit built into the indoor unit 200. In at least a portion of the utilization-side refrigerant circuit 10C, a first metal component connected to a first copper pipe 13 and a second metal component connected to a second copper pipe 14 can be configured as required.

[0067] like Figure 1 As shown, the first refrigerant piping assembly 10a can be connected in the gas-side refrigerant circuit 10A to one or more of the following intervals: between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0068] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11 of the iron system. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0069] These areas are close to the compressor 2, which generates continuous vibration during operation, and the four-way valve 3, which generates intermittent vibration during switching. If unreinforced refrigerant piping made of phosphorus deoxidized copper or similar materials is connected in such areas, fatigue failure may occur due to repeated stress caused by vibration during equipment operation. In contrast, the first refrigerant piping assembly 10a is reinforced with alloying elements because the first copper tube 13 constituting the end is reinforced, thus suppressing fatigue failure caused by vibration. Therefore, the detachment of the first refrigerant piping assembly 10a and the breakage of the parts made of copper-based metals can be reduced.

[0070] On the other hand, the second refrigerant piping assembly 10b can be connected in the liquid-side refrigerant circuit 10B to one or more sections between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19.

[0071] That is, the iron-based second refrigerant piping 12, as the second metal component of the iron system, can be configured between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid-side stop valve 19, through the assembly of the second refrigerant piping assembly 10b. A second copper pipe 14 is pre-connected to the end of such an iron-based second refrigerant piping 12. The second copper pipe 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0072] These zones are away from the compressor 2, which generates continuous vibration during operation, and the four-way valve 3, which generates intermittent vibration during switching. Since the outdoor heat exchanger 4 is located between these zones and the compressor 2 and the four-way valve 3, vibrations during equipment operation are unlikely to affect it. For these zones, conventionally used phosphorus-deoxidized copper tubing or low-alloy copper tubing with fewer alloying elements and lower raw material costs can be used as the ends of the refrigerant piping assembly 10b. By using such refrigerant piping, fatigue damage caused by vibration is avoided, and the refrigerant circuit 10 can be formed at low cost.

[0073] Additionally, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected in one or more sections of the refrigerant circuit 10C on the utilization side: between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18. Figure 1 In this case, a second refrigerant piping assembly 10b is connected in these intervals, but in cases where vibration or strength becomes a problem in the indoor unit 200, a first refrigerant piping assembly 10a may also be connected in these intervals.

[0074] Furthermore, in the refrigerant circuit 10, the length along the centerline of the first copper pipe 13 is set to be shorter than the length along the centerline of the first refrigerant piping 11 of the iron system. Additionally, the length along the centerline of the second copper pipe is preferably set to be shorter than the length along the centerline of the second refrigerant piping 12 of the iron system.

[0075] With this length relationship, the ratio of the length of the iron-based refrigerant pipe to that of the copper pipe becomes larger in the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b, thus enabling the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b to be more cost-effective.

[0076] However, in the section connecting the oil outlet of the oil separator 8 to the compressor 2, the length along the centerline of the first iron-based refrigerant piping 11 is preferably shorter than the length along the centerline of the first copper pipe 13 connected to the first iron-based refrigerant piping 11. In the section connecting the oil outlet of the oil separator 8 to the compressor 2, even without the first refrigerant piping assembly 10a, a copper-based refrigerant piping made of copper or copper alloys can be connected.

[0077] The section connecting the oil outlet of the oil separator 8 to the compressor 2 is the section where refrigeration oil flows back towards the compressor 2, and is generally designed to be relatively short. Therefore, this section has a lower necessity to convert copper-based refrigerant piping to iron-based refrigerant piping. With this length relationship, the design freedom of the refrigerant circuit 10 can be increased, and the overall cost can be suppressed.

[0078] In the refrigerant circuit 10, the wall thickness of the iron-based first refrigerant pipe 11 is preferably greater than the wall thickness of the iron-based second refrigerant pipe 12. Furthermore, the wall thickness of the first copper pipe 13 is preferably greater than both the wall thickness of the iron-based first refrigerant pipe 11 and the wall thickness of the iron-based second refrigerant pipe 12. Additionally, the wall thickness of the second copper pipe 14 is preferably greater than both the wall thickness of the iron-based first refrigerant pipe 11 and the wall thickness of the iron-based second refrigerant pipe 12.

[0079] With such wall thickness, the main concern is the area where the gaseous refrigerant flows. Since the refrigerant piping is set to be relatively thick, the pressure resistance of the refrigerant piping can be adequately ensured. Furthermore, in the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b, since the thickness ratio of the iron-based refrigerant piping is larger compared to the copper pipe, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can be made more cost-effective.

[0080] When the first refrigerant piping assembly 10a is connected to the compressor 2, that is, when the iron-based first refrigerant piping 11 forms a piping connecting the compressor 2 and the accumulator 7, the compressor 2 and the oil separator 8, or the compressor 2 and the four-way valve 3, and the first copper pipe 13 is connected to the discharge side and the suction side of the compressor 2, the compressor 2 is preferably a scroll compressor or a dual rotary compressor.

[0081] If the compressor 2 is of this type, the vibration generated during operation is smaller compared to single rotary or oscillating compressors. Therefore, even if the first copper pipe 13 constituting the first refrigerant piping assembly 10a is strengthened by adding alloying elements, fatigue failure of the first refrigerant piping assembly 10a and the first copper pipe 13 constituting the first refrigerant piping assembly 10a can be further reduced.

[0082] According to such an air conditioner 1, since the refrigerant circuit 10 is formed using refrigerant piping assemblies 10a and 10b, after the copper pipes and iron-based refrigerant piping are pre-joined by brazing in a furnace under controlled conditions, the ends of the copper pipes joined to the iron-based refrigerant piping can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping, existing equipment and methods can be used for connections relative to the existing copper-based refrigerant piping and equipment, and material costs can be reduced. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping to copper-based refrigerant piping and equipment, while suppressing manufacturing costs.

[0083] Furthermore, the refrigerant piping assemblies 10a and 10b utilize copper pipes with varying chemical compositions at their ends, depending on their position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. Regarding the copper pipes connected to the compressor 2 and four-way valve 3, which vibrate during operation, tensile strength and fatigue strength are enhanced through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements. Conversely, for copper pipes not connected to them, costs are reduced by omitting or minimizing the addition of alloying elements. Therefore, a refrigeration cycle device can be provided with refrigerant piping exhibiting high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0084] <Second Implementation>

[0085] Figure 2 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the second embodiment of the present invention. Figure 2 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 2 As shown, the air conditioner 2 can also include an iron-based oil separator 8a, which may be made of iron, iron alloy, or stainless steel. The iron-based oil separator 8a can be assembled as a component with respect to the refrigerant circuit 10. The other main structures of the air conditioner 2 are the same as those of the air conditioner 1 described above.

[0086] The iron-based oil separator 8a can be prepared as an oil separator assembly 10c. The oil separator assembly 10c is an assembly in which a first copper pipe 13 is joined to the connecting part of the iron-based oil separator 8a, which constitutes an iron-based metal component. The oil separator assembly 10c can be connected to the refrigerant piping that forms the refrigerant circuit 10 and the equipment that forms the refrigerant circuit 10.

[0087] The oil separator assembly 10c is an assembled component formed from an iron-based oil separator 8a and a first copper tube 13. The first copper tube 13 is formed from a copper alloy containing more than 0.040% by mass of P, including one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe. The first copper tube 13 is a copper alloy whose mechanical properties, such as tensile strength and fatigue strength, are improved through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements. The iron-based oil separator 8a and the first copper tube 13 are joined together by furnace brazing.

[0088] As an iron-based oil separator 8a, it is possible to use an oil separator with an iron body and connecting parts, an oil separator with an iron alloy body and connecting parts, or an oil separator with a stainless steel body and connecting parts. The first copper pipe 13 can be connected to each port of the iron-based oil separator 8a, or to the end of an iron-based refrigerant pipe pre-connected to each port of the iron-based oil separator 8a.

[0089] Examples of iron and iron alloys include steel, carbon steel, and alloy steel. Examples of stainless steel include austenitic stainless steels such as SUS304. If an iron-based oil separator 8a is used, it can reduce raw material costs compared to copper-based separators.

[0090] The oil separator assembly 10c can be joined to other refrigerant piping and equipment forming the refrigerant circuit 10, for example, by atmospheric brazing, flaring, or welding. During the assembly of the refrigerant circuit 10, the oil separator assembly 10c, formed by furnace brazing, can be easily joined to existing copper-based refrigerant piping and equipment using conventional equipment. Furthermore, since the first copper tube 13 is prevented from being heated in the furnace, the decrease in strength caused by grain coarsening can be prevented.

[0091] The oil separator assembly 10c can be formed by connecting the first copper pipe 13 to a portion of the connection of the iron-based oil separator 8a, or by connecting it to all the connection portions of the iron-based oil separator 8a. However, when connecting the oil separator assembly 10c to copper-based refrigerant piping and equipment, it is preferable to connect the first copper pipe 13 to the corresponding connection portion of the oil separator assembly 10c.

[0092] exist Figure 2 In this configuration, the refrigerant circuit 10 is formed by connecting a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), an outdoor expansion valve 5a (serving as a pressure reducer), an indoor expansion valve 5b, an indoor heat exchanger 6 (serving as a utilization-side heat exchanger), an energy storage tank 7, an iron-based oil separator 8a, a gas-side stop valve 18, and a liquid-side stop valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0093] like Figure 2 As shown, the oil separator assembly 10c is connected between the compressor 2 and the four-way valve 3 in the gas-side refrigerant circuit 10A. That is, the iron-based oil separator 8a, which constitutes the first metal component of the iron system, can be configured between the compressor 2 and the four-way valve 3 through the assembly of the oil separator assembly 10c. The first copper pipe 13 is pre-connected to the connection portion of the iron-based oil separator 8a.

[0094] In addition, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more of the following sections: between the energy storage unit 7 and the compressor 2, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the energy storage unit 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0095] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the accumulator 7 and the compressor 2, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0096] On the other hand, the second refrigerant piping assembly 10b in the liquid-side refrigerant circuit 10B can be connected to one or more of the intervals between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19.

[0097] That is, the iron-based second refrigerant piping 12, as the second metal component of the iron system, can be configured between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid-side stop valve 19, through the assembly of the second refrigerant piping assembly 10b. The second copper pipe 14 is pre-connected to the end of such iron-based second refrigerant piping 12. The second copper pipe 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0098] Additionally, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected to one or more sections in the refrigerant circuit 10C on the utilization side: between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18. Figure 2 In this case, a second refrigerant piping assembly 10b is connected in these intervals, but in cases where vibration or strength becomes a problem in the indoor unit 200, a first refrigerant piping assembly 10a may also be connected in these intervals.

[0099] Furthermore, in the refrigerant circuit 10, the length along the center line of the first copper pipe 13, the length along the center line of the second copper pipe 14, the wall thickness of the iron-based first refrigerant piping 11, the wall thickness of the iron-based second refrigerant piping 12, the wall thickness of the first copper pipe 13, the wall thickness of the second copper pipe 14, and the compressor 2 are preferably configured to be the same as those in the air conditioner 1 described above.

[0100] According to such an air conditioner 2, since the refrigerant circuit 10 is formed using refrigerant piping assemblies 10a and 10b and an oil separator assembly 10c, after the copper pipes are pre-joined with the iron-based refrigerant piping and the iron-based oil separator by furnace brazing in a controlled environment, the ends of the copper pipes joined to the iron-based refrigerant piping and the iron-based oil separator can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping and equipment, existing equipment and methods can be used to make connections relative to the existing copper-based refrigerant piping and equipment, and material costs can be reduced. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment relative to copper-based refrigerant piping and equipment, and suppresses manufacturing costs.

[0101] Furthermore, the refrigerant piping assemblies 10a and 10b, and the oil separator assembly 10c, use copper pipes with varying chemical compositions at their ends based on their position relative to the vibrating equipment, thus resulting in high vibration resistance of the refrigerant piping. Regarding the copper pipes connected to the compressor 2 and the four-way valve 3, which vibrate during operation, tensile strength and fatigue strength are enhanced through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements. On the other hand, for copper pipes not connected to them, costs are suppressed by omitting or reducing the amount of alloying elements. Therefore, a refrigeration cycle device can be provided with refrigerant piping that exhibits high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0102] <Third Implementation Method>

[0103] Figure 3 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the third embodiment of the present invention. Figure 3 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 3 As shown, the air conditioner 3 can also be equipped with a four-way valve 3a made of iron, iron alloy, or stainless steel. The iron-based four-way valve 3a can be assembled as a component with respect to the refrigerant circuit 10. The other main structures of the air conditioner 3 are the same as those of the air conditioner 1 described above.

[0104] The iron-based four-way valve 3a can be prepared as a four-way valve assembly 10d. The four-way valve assembly 3d is an assembly in which a first copper pipe 13 is joined to the connection part of the iron-based four-way valve 3a, which constitutes an iron-based metal component. The four-way valve assembly 3d can be connected to the refrigerant piping that forms the refrigerant circuit 10 and the equipment that forms the refrigerant circuit 10.

[0105] The four-way valve assembly 10d is an assembled component, formed from an iron-based four-way valve 3a and a first copper tube 13. The first copper tube 13 is formed of a copper alloy containing one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe, and more than 0.040% by mass of P. The first copper tube 13 is a copper alloy whose mechanical properties, such as tensile strength and fatigue strength, are improved through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements. The iron-based four-way valve 3a and the first copper tube 13 are joined together by furnace brazing.

[0106] As an iron-based four-way valve 3a, it is possible to use a four-way valve with an iron body and connecting parts, a four-way valve with an iron alloy body and connecting parts, or a four-way valve with a stainless steel body and connecting parts. The first copper pipe 13 can be connected to each port of the iron-based four-way valve 3a, or to the end of an iron-based refrigerant pipe pre-connected to each port of the iron-based four-way valve 3a.

[0107] Examples of iron and iron alloys include steel, carbon steel, and alloy steel. Examples of stainless steel include austenitic stainless steels such as SUS304. If an iron-based four-way valve 3a is used, it can reduce raw material costs compared to copper-based valves.

[0108] The four-way valve assembly 10d can be joined to other refrigerant piping and equipment forming the refrigerant circuit 10, for example, by atmospheric brazing, flaring, or welding. During the assembly of the refrigerant circuit 10, the four-way valve assembly 10d, formed by furnace brazing, can be easily joined to existing copper-based refrigerant piping and equipment using conventional equipment. Furthermore, since the first copper tube 13 can be prevented from being heated in the furnace, the decrease in strength caused by grain coarsening can be prevented.

[0109] The four-way valve assembly 10d can be formed by connecting the first copper pipe 13 to a portion of the connection of the iron-based four-way valve 3a, or by connecting it to all the connection portions of the iron-based four-way valve 3a. However, when connecting the four-way valve assembly 10d to copper-based refrigerant piping or equipment, it is preferable to connect the first copper pipe 13 to the corresponding connection portion of the four-way valve assembly 10d.

[0110] exist Figure 3 In this configuration, the refrigerant circuit 10 is formed by connecting the compressor 2, the iron-based four-way valve 3a, the outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), the outdoor expansion valve 5a (serving as a pressure reducer), the indoor expansion valve 5b, the indoor heat exchanger 6 (serving as a utilization-side heat exchanger), the energy storage tank 7, the oil separator 8, the gas-side shut-off valve 18, and the liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0111] like Figure 3 As shown, the four-way valve assembly 10d in the gas-side refrigerant circuit 10A can be connected relative to the oil separator 8, the gas-side shut-off valve 18, the accumulator 7, and the outdoor heat exchanger 4. That is, the iron-based four-way valve 3a, constituting the first metal component of the iron system, can be configured relative to the oil separator 8, the gas-side shut-off valve 18, the accumulator 7, and the outdoor heat exchanger 4 through the assembly of the four-way valve assembly 10d. The first copper pipe 13 is pre-connected to the connection portion of the iron-based four-way valve 3a.

[0112] In addition, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more sections between the energy storage 7 and the compressor 2, and between the compressor 2 and the oil separator 8.

[0113] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the energy storage unit 7 and the compressor 2, or between the compressor 2 and the oil separator 8, through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0114] On the other hand, the second refrigerant piping assembly 10b in the liquid-side refrigerant circuit 10B can be connected to one or more of the intervals between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19.

[0115] That is, the iron-based second refrigerant piping 12, as the second metal component of the iron system, can be configured between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid-side stop valve 19, through the assembly of the second refrigerant piping assembly 10b. The second copper pipe 14 is pre-connected to the end of such iron-based second refrigerant piping 12. The second copper pipe 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0116] Additionally, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected in one or more sections of the refrigerant circuit 10C on the utilization side: between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18. Figure 3 In this case, a second refrigerant piping assembly 10b is connected in these intervals, but in cases where vibration or strength becomes a problem in the indoor unit 200, a first refrigerant piping assembly 10a may also be connected in these intervals.

[0117] Furthermore, in the refrigerant circuit 10, the length along the center line of the first copper pipe 13, the length along the center line of the second copper pipe 14, the wall thickness of the iron-based first refrigerant piping 11, the wall thickness of the iron-based second refrigerant piping 12, the wall thickness of the first copper pipe 13, the wall thickness of the second copper pipe 14, and the compressor 2 are preferably configured to be the same as those in the air conditioner 1 described above.

[0118] According to such an air conditioner 3, since the refrigerant circuit 10 is formed using refrigerant piping assemblies 10a and 10b and a four-way valve assembly 10d, after the copper pipes are pre-joined with the iron-based refrigerant piping and the iron-based four-way valve by furnace brazing in a controlled environment, the ends of the copper pipes joined to the iron-based refrigerant piping and the iron-based four-way valve can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping and equipment, existing equipment and methods can be used to make connections relative to the existing copper-based refrigerant piping and equipment, and material costs can be reduced. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment relative to copper-based refrigerant piping and equipment, and suppresses manufacturing costs.

[0119] Furthermore, the refrigerant piping assemblies 10a and 10b, and the four-way valve assembly 10d, respectively utilize copper-based refrigerant piping with varying chemical compositions at their ends, depending on their position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. Regarding the copper pipes connected to the compressor 2 and the four-way valve 3, which vibrate during operation, tensile strength and fatigue strength are enhanced through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements. Conversely, for copper pipes not connected to them, costs are reduced by omitting or minimizing the addition of alloying elements. Therefore, a refrigeration cycle device can be provided with refrigerant piping exhibiting high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0120] <Fourth Implementation>

[0121] Figure 4 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the fourth embodiment of the present invention. Figure 4 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 4 As shown, the air conditioner 4 can also be installed in a structure without an oil separator. The other main structures of the air conditioner 4 are the same as those of the air conditioner 1 described above.

[0122] exist Figure 4In this configuration, the refrigerant circuit 10 is formed by connecting a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), an outdoor expansion valve 5a (serving as a pressure reducer), an indoor expansion valve 5b, an indoor heat exchanger 6 (serving as a utilization-side heat exchanger), an energy storage unit 7, a gas-side shut-off valve 18, and a liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0123] like Figure 4 As shown, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more of the following intervals: between the energy storage unit 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the energy storage unit 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0124] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the accumulator 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0125] On the other hand, the second refrigerant piping assembly 10b in the liquid-side refrigerant circuit 10B can be connected to one or more of the intervals between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19.

[0126] That is, the iron-based second refrigerant piping 12, as the second metal component of the iron system, can be configured between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, or between the outdoor expansion valve 5a and the liquid-side stop valve 19, through the assembly of the second refrigerant piping assembly 10b. The second copper pipe 14 is pre-connected to the end of such iron-based second refrigerant piping 12. The second copper pipe 14 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0127] Additionally, the first refrigerant piping assembly 10a and the second refrigerant piping assembly 10b can also be connected in one or more sections of the refrigerant circuit 10C on the utilization side: between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18. Figure 4In this case, a second refrigerant piping assembly 10b is connected in these intervals, but in cases where vibration or strength becomes a problem in the indoor unit 200, a first refrigerant piping assembly 10a may also be connected in these intervals.

[0128] Furthermore, in the refrigerant circuit 10, the length along the center line of the first copper pipe 13, the length along the center line of the second copper pipe 14, the wall thickness of the iron-based first refrigerant piping 11, the wall thickness of the iron-based second refrigerant piping 12, the wall thickness of the first copper pipe 13, the wall thickness of the second copper pipe 14, and the compressor 2 are preferably configured to be the same as those in the air conditioner 1 described above.

[0129] According to such an air conditioner 4, since the refrigerant circuit 10 is formed using refrigerant piping assemblies 10a and 10b, after the copper pipes and iron-based refrigerant piping are pre-joined by brazing in a furnace under controlled conditions, the ends of the copper pipes joined to the iron-based refrigerant piping can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping, existing equipment and methods can be used for connections relative to the existing copper-based refrigerant piping and equipment, thus reducing material costs. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment relative to copper-based refrigerant piping and equipment, thereby reducing manufacturing costs.

[0130] Furthermore, the refrigerant piping assemblies 10a and 10b utilize copper-based refrigerant piping with varying chemical compositions at their ends, depending on their position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. Regarding the copper pipes connected to the compressor 2 and four-way valve 3, which vibrate during operation, tensile and fatigue strength are enhanced through solid solution strengthening and precipitation strengthening caused by the addition of alloying elements. Conversely, for copper pipes not connected to these components, costs are reduced by omitting or minimizing the addition of alloying elements. Therefore, a refrigeration cycle device can be provided with refrigerant piping exhibiting high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0131] <Fifth Implementation>

[0132] Figure 5 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the fifth embodiment of the present invention. Figure 5 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 5 As shown, the air conditioner 5 can also be installed in a structure that does not have a second refrigerant piping assembly 10b. The other main structures of the air conditioner 5 are the same as those of the air conditioner 1 described above.

[0133] exist Figure 5 In this configuration, the refrigerant circuit 10 is formed by connecting a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), an outdoor expansion valve 5a (serving as a pressure reducer), an indoor expansion valve 5b, an indoor heat exchanger 6 (serving as a utilization-side heat exchanger), an energy storage tank 7, an oil separator 8, a gas-side shut-off valve 18, and a liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0134] like Figure 5 As shown, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more of the following intervals: between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0135] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the accumulator 7 and the compressor 2, between the compressor 2 and the oil separator 8, between the oil separator 8 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11 of the iron system. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0136] On the other hand, instead of connecting the second refrigerant piping assembly 10b between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper or copper-based refrigerant piping 15 is connected. Figure 5 In the process, copper components 20 are joined to each device, but the copper components 20 may be omitted.

[0137] That is, instead of assembling components to configure a second iron-based refrigerant pipe 12 between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper-based refrigerant pipe 15 is connected. This copper-based refrigerant pipe 15 is formed of copper that substantially does not contain one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, or is formed of a copper alloy in which the content of these alloying elements is lower than that in the first copper pipe 13. The copper-based refrigerant pipe 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0138] These sections primarily allow for the flow of liquid refrigerant, thus enabling the refrigerant piping to be relatively thin. Furthermore, these sections are away from the compressor 2, which generates continuous vibration during operation, and the four-way valve 3, which generates intermittent vibration during switching. Since the outdoor heat exchanger 4 is located between the compressor 2 and the four-way valve 3, vibrations from the equipment during operation are unlikely to affect it. For these sections, there is less need to use refrigerant piping assemblies with low-cost iron-based refrigerant piping; conventionally used phosphorus-deoxidized copper pipes or low-alloy copper alloy pipes with fewer alloying elements and lower raw material costs can be used.

[0139] Additionally, in one or more of the following intervals—between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18—only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, and the copper-based refrigerant piping 15 can be connected. Figure 5 In this case, copper-based refrigerant piping 15 with a lower content of alloying elements than that in the first copper pipe 13 is connected in these intervals. However, in cases where vibration or strength becomes a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloying elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may also be connected in these intervals.

[0140] Furthermore, in the refrigerant circuit 10, the length along the centerline of the first copper pipe 13, the thickness of the wall of the iron-based first refrigerant piping 11, the thickness of the wall of the first copper pipe 13, and the configuration of the compressor 2 are preferably set to be the same as those of the air conditioner 1 described above.

[0141] According to such an air conditioner 5, since the refrigerant circuit 10 is formed using a refrigerant piping assembly 10a, after the copper pipes and iron-based refrigerant piping are pre-joined by brazing in a furnace under controlled conditions, the ends of the copper pipes joined to the iron-based refrigerant piping can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping, existing equipment and methods can be used for connections relative to the existing copper-based refrigerant piping and equipment, thus reducing material costs. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment relative to copper-based refrigerant piping and equipment, thereby reducing manufacturing costs.

[0142] Furthermore, the refrigerant piping assembly 10a uses copper-based refrigerant piping with varying chemical compositions at its ends, depending on its position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. The refrigerant piping assembly 10a is used in the vicinity of the compressor 2 and four-way valve 3, which vibrate during operation, and in the region away from these components, using copper-based refrigerant piping. Therefore, including the thinner sections of the refrigerant piping, the overall cost of the refrigerant circuit 10 can be reduced. Consequently, a refrigeration cycle device can be provided with refrigerant piping that exhibits high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0143] <Sixth Implementation Method>

[0144] Figure 6 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the sixth embodiment of the present invention. Figure 6 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 6 As shown, the air conditioner 6 can also be configured with the following structure: it has an oil separator 8a made of iron, iron alloy, or stainless steel, and does not have a second refrigerant piping assembly 10b. The other main structures of the air conditioner 6 are the same as those of the air conditioner 2 described above.

[0145] exist Figure 6 In this configuration, the refrigerant circuit 10 is formed by connecting a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), an outdoor expansion valve 5a (serving as a pressure reducer), an indoor expansion valve 5b, an indoor heat exchanger 6 (serving as a utilization-side heat exchanger), an energy storage tank 7, an iron-based oil separator 8a, a gas-side shut-off valve 18, and a liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0146] like Figure 6 As shown, the oil separator assembly 10c is connected between the compressor 2 and the four-way valve 3 in the gas-side refrigerant circuit 10A. That is, the iron-based oil separator 8a, constituting the first iron-based metal component, can be configured between the compressor 2 and the four-way valve 3 through the assembly of the oil separator assembly 10c. The copper-based first refrigerant pipe 13 is pre-connected to the connection portion of the iron-based oil separator 8a.

[0147] In addition, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more of the following sections: between the energy storage unit 7 and the compressor 2, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the energy storage unit 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0148] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the accumulator 7 and the compressor 2, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0149] On the other hand, instead of connecting the second refrigerant piping assembly 10b between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper or copper-based refrigerant piping 15 is connected. Figure 6 In the process, copper components 20 are joined to each device, but the copper components 20 may be omitted.

[0150] That is, instead of assembling components to configure a second iron-based refrigerant pipe 12 between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper-based refrigerant pipe 15 is connected. This copper-based refrigerant pipe 15 is formed of copper that substantially does not contain one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, or is formed of a copper alloy in which the content of these alloying elements is lower than that in the first copper pipe 13. The copper-based refrigerant pipe 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0151] These sections primarily allow for the flow of liquid refrigerant, thus enabling the refrigerant piping to be relatively thin. Furthermore, these sections are away from the compressor 2, which generates continuous vibration during operation, and the four-way valve 3, which generates intermittent vibration during switching. Since the outdoor heat exchanger 4 is located between the compressor 2 and the four-way valve 3, vibrations from the equipment during operation are unlikely to affect it. For these sections, there is less need to use refrigerant piping assemblies with low-cost iron-based refrigerant piping; conventionally used phosphorus-deoxidized copper pipes or low-alloy copper alloy pipes with fewer alloying elements and lower raw material costs can be used.

[0152] Additionally, in one or more of the following intervals—between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18—only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, and the copper-based refrigerant piping 15 can be connected. Figure 6 In this case, copper-based refrigerant piping 15 with a lower content of alloying elements than that in the first copper pipe 13 is connected in these intervals. However, in cases where vibration or strength becomes a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloying elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may also be connected in these intervals.

[0153] Furthermore, in the refrigerant circuit 10, the length along the centerline of the first copper pipe 13, the thickness of the wall of the iron-based first refrigerant piping 11, the thickness of the wall of the first copper pipe 13, and the configuration of the compressor 2 are preferably set to be the same as those of the air conditioner 1 described above.

[0154] According to such an air conditioner 6, since the refrigerant circuit 10 is formed using a refrigerant piping assembly 10a and an oil separator assembly 10c, after the copper pipes are pre-joined with the iron-based refrigerant piping and the iron-based oil separator by furnace brazing in a controlled environment, the ends of the copper pipes joined to the iron-based refrigerant piping and the iron-based oil separator can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping and equipment, existing equipment and methods can be used to make connections relative to the existing copper-based refrigerant piping and equipment, and material costs can be reduced. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment relative to copper-based refrigerant piping and equipment, and suppresses manufacturing costs.

[0155] Furthermore, the refrigerant piping assembly 10a and the oil separator assembly 10c utilize copper-based refrigerant piping with varying chemical compositions at their ends, depending on their position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. The refrigerant piping assembly 10a is used in the vicinity of the compressor 2 and the four-way valve 3, which vibrate during operation, while copper-based refrigerant piping is used in the region away from these components. Therefore, including the thinner sections of the refrigerant piping, the overall cost of the refrigerant circuit 10 can be reduced. Consequently, a refrigeration cycle device can be provided with refrigerant piping that exhibits high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0156] <Seventh Implementation>

[0157] Figure 7 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the seventh embodiment of the present invention. Figure 7 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 7 As shown, the air conditioner 7 can also be configured with the following structure: it has a four-way valve 3a made of iron, iron alloy, or stainless steel, and does not have a second refrigerant piping assembly 10b. The other main structures of the air conditioner 7 are the same as those of the air conditioner 3 described above.

[0158] exist Figure 7 In this configuration, the refrigerant circuit 10 is formed by connecting the compressor 2, the iron-based four-way valve 3, the outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), the outdoor expansion valve 5a (serving as a pressure reducer), the indoor expansion valve 5b, the indoor heat exchanger 6 (serving as a utilization-side heat exchanger), the energy storage tank 7, the oil separator 8, the gas-side shut-off valve 18, and the liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0159] like Figure 7 As shown, the four-way valve assembly 10d in the gas-side refrigerant circuit 10A can be connected relative to the oil separator 8, the gas-side shut-off valve 18, the accumulator 7, and the outdoor heat exchanger 4. That is, the iron-based four-way valve 3a, constituting the first metal component of the iron system, can be configured relative to the oil separator 8, the gas-side shut-off valve 18, the accumulator 7, and the outdoor heat exchanger 4 through the assembly of the four-way valve assembly 10d. The first copper pipe 13 is pre-connected to the connection portion of the iron-based four-way valve 3a.

[0160] In addition, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more sections between the energy storage 7 and the compressor 2, and between the compressor 2 and the oil separator 8.

[0161] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the energy storage unit 7 and the compressor 2, or between the compressor 2 and the oil separator 8, through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0162] On the other hand, instead of connecting the second refrigerant piping assembly 10b between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper or copper-based refrigerant piping 15 is connected. Figure 7 In the process, copper components 20 are joined to each device, but the copper components 20 may be omitted.

[0163] That is, instead of assembling components to configure a second iron-based refrigerant pipe 12 between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper-based refrigerant pipe 15 is connected. This copper-based refrigerant pipe 15 is formed of copper that substantially does not contain one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, or is formed of a copper alloy in which the content of these alloying elements is lower than that in the first copper pipe 13. The copper-based refrigerant pipe 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0164] These sections primarily allow for the flow of liquid refrigerant, thus enabling the refrigerant piping to be relatively thin. Furthermore, these sections are away from the compressor 2, which generates continuous vibration during operation, and the four-way valve 3, which generates intermittent vibration during switching. Since the outdoor heat exchanger 4 is located between the compressor 2 and the four-way valve 3, vibrations from the equipment during operation are unlikely to affect it. For these sections, there is less need to use refrigerant piping assemblies with low-cost iron-based refrigerant piping; conventionally used phosphorus-deoxidized copper pipes or low-alloy copper alloy pipes with fewer alloying elements and lower raw material costs can be used.

[0165] Additionally, in one or more of the following intervals—between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18—only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, and the copper-based refrigerant piping 15 can be connected. Figure 7In this case, copper-based refrigerant piping 15 with a lower content of alloying elements than that in the first copper pipe 13 is connected in these intervals. However, in cases where vibration or strength becomes a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloying elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may also be connected in these intervals.

[0166] Furthermore, in the refrigerant circuit 10, the length along the centerline of the first copper pipe 13, the thickness of the wall of the iron-based first refrigerant piping 11, the thickness of the wall of the first copper pipe 13, and the configuration of the compressor 2 are preferably set to be the same as those of the air conditioner 1 described above.

[0167] According to such an air conditioner 7, since the refrigerant circuit 10 is formed using a refrigerant piping assembly 10a and a four-way valve assembly 10d, after the copper pipes are pre-joined with the iron-based refrigerant piping and the iron-based four-way valve by furnace brazing under controlled conditions, the ends of the copper pipes joined to the iron-based refrigerant piping and the iron-based four-way valve can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping and equipment, existing equipment and methods can be used to make connections relative to the existing copper-based refrigerant piping and equipment, and material costs can be reduced. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment relative to copper-based refrigerant piping and equipment, and reduces manufacturing costs.

[0168] Furthermore, the refrigerant piping assembly 10a and the four-way valve assembly 10d utilize copper-based refrigerant piping with varying chemical compositions at their ends, depending on their position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. The refrigerant piping assembly 10a is used in the vicinity of the compressor 2 and the four-way valve 3, where vibration occurs during operation, while copper-based refrigerant piping is used in areas further away from these components. Therefore, including areas where the refrigerant piping is thinner, the overall cost of the refrigerant circuit 10 can be reduced. Consequently, a refrigeration cycle device with highly vibration-resistant refrigerant piping can be provided, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0169] <Eighth Implementation Method>

[0170] Figure 8 This is a diagram showing the refrigerant circuit of the refrigeration cycle apparatus according to the eighth embodiment of the present invention. Figure 8 This refers to an example of the refrigerant circuit equipped in an air conditioner, which is an example of a refrigeration cycle device. For example... Figure 8As shown, the air conditioner 8 can also be configured without an oil separator and a second refrigerant piping assembly 10b. The other main structures of the air conditioner 8 are the same as those of the air conditioner 4 described above.

[0171] exist Figure 8 In this configuration, the refrigerant circuit 10 is formed by connecting a compressor 2, a four-way valve 3, an outdoor heat exchanger 4 (serving as a heat source-side heat exchanger), an outdoor expansion valve 5a (serving as a pressure reducer), an indoor expansion valve 5b, an indoor heat exchanger 6 (serving as a utilization-side heat exchanger), an energy storage tank 7, an oil separator 8, a gas-side shut-off valve 18, and a liquid-side shut-off valve 19 via refrigerant piping. The refrigerant circuit 10 consists of at least a gas-side refrigerant circuit 10A, a liquid-side refrigerant circuit 10B, and a utilization-side refrigerant circuit 10C.

[0172] like Figure 8 As shown, the first refrigerant piping assembly 10a in the gas-side refrigerant circuit 10A can be connected to one or more of the following intervals: between the energy storage unit 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the energy storage unit 7, and between the four-way valve 3 and the outdoor heat exchanger 4.

[0173] That is, the first refrigerant piping 11, which is the first metal component of the iron system, can be configured between the accumulator 7 and the compressor 2, between the compressor 2 and the four-way valve 3, between the four-way valve 3 and the gas-side stop valve 18, between the four-way valve 3 and the accumulator 7, or between the four-way valve 3 and the outdoor heat exchanger 4 through the assembly of the first refrigerant piping assembly 10a. The first copper pipe 13 is pre-connected to the end of such the first refrigerant piping 11. The first copper pipe 13 can be connected to the four-way valve 3 side of the main pipe 4b, etc., relative to the outdoor heat exchanger 4.

[0174] On the other hand, instead of connecting the second refrigerant piping assembly 10b between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper-based refrigerant piping 15, made of copper or a copper alloy, is connected. Figure 8 In the process, copper components 20 are joined to each device, but the copper components 20 may be omitted.

[0175] That is, instead of assembling components to configure a second iron-based refrigerant pipe 12 between the outdoor heat exchanger 4 and the outdoor expansion valve 5a, and between the outdoor expansion valve 5a and the liquid-side stop valve 19, a copper-based refrigerant pipe 15 is connected. This copper-based refrigerant pipe 15 is formed of copper that substantially does not contain one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, or is formed of a copper alloy in which the content of these alloying elements is lower than that in the first copper pipe 13. The copper-based refrigerant pipe 15 can be connected to the distributor 4c side of the main body 4a, the main body 4a side of the distributor 4c, the outdoor expansion valve 5a side, etc., relative to the outdoor heat exchanger 4.

[0176] These sections primarily allow for the flow of liquid refrigerant, thus enabling the refrigerant piping to be relatively thin. Furthermore, these sections are away from the compressor 2, which generates continuous vibration during operation, and the four-way valve 3, which generates intermittent vibration during switching. Since the outdoor heat exchanger 4 is located between the compressor 2 and the four-way valve 3, vibrations from the equipment during operation are unlikely to affect it. For these sections, there is less need to use refrigerant piping assemblies with low-cost iron-based refrigerant piping; conventionally used phosphorus-deoxidized copper pipes or low-alloy copper alloy pipes with fewer alloying elements and lower raw material costs can be used.

[0177] Additionally, in one or more of the following intervals—between the indoor heat exchanger 6 and the indoor expansion valve 5b, between the indoor expansion valve 5b and the liquid-side stop valve 19, and between the indoor heat exchanger 6 and the gas-side stop valve 18—only the first refrigerant piping assembly 10a, the second refrigerant piping assembly 10b, and the copper-based refrigerant piping 15 can be connected. Figure 8 In this case, copper-based refrigerant piping 15 with a lower content of alloying elements than that in the first copper pipe 13 is connected in these intervals. However, in cases where vibration or strength becomes a problem in the indoor unit 200, copper-based refrigerant piping 15 containing one or more alloying elements selected from P, Co, Sn, Zn, Ni, Zr, and Fe may also be connected in these intervals.

[0178] Furthermore, in the refrigerant circuit 10, the length along the centerline of the first copper pipe 13, the thickness of the wall of the iron-based first refrigerant piping 11, the thickness of the wall of the first copper pipe 13, and the configuration of the compressor 2 are preferably set to be the same as those of the air conditioner 1 described above.

[0179] According to such an air conditioner 8, since the refrigerant circuit 10 is formed using a refrigerant piping assembly 10a, after the copper pipes and iron-based refrigerant piping are pre-joined by brazing in a furnace under controlled conditions, the ends of the copper pipes joined to the iron-based refrigerant piping can be connected to the existing copper-based refrigerant piping and equipment in any environment, such as the atmosphere. Since a portion of the refrigerant circuit 10 is replaced with iron-based refrigerant piping, connections to the existing copper-based refrigerant piping and equipment can be made using existing equipment and methods, thus reducing material costs. Therefore, a refrigeration cycle device can be provided that, despite the presence of joints between dissimilar metals, appropriately joins iron-based refrigerant piping and equipment to copper-based refrigerant piping and equipment, thereby reducing manufacturing costs.

[0180] Furthermore, the refrigerant piping assembly 10a uses copper-based refrigerant piping with varying chemical compositions at its ends, depending on its position relative to the vibrating equipment. This results in higher vibration resistance for the refrigerant piping. The refrigerant piping assembly 10a is used in the vicinity of the compressor 2 and four-way valve 3, which vibrate during operation, and in the region away from these components, using copper-based refrigerant piping. Therefore, including the thinner sections of the refrigerant piping, the overall cost of the refrigerant circuit 10 can be reduced. Consequently, a refrigeration cycle device can be provided with refrigerant piping that exhibits high vibration resistance, suppressing refrigerant piping detachment and breakage, and reducing manufacturing costs.

[0181] Next, for copper tubes that are joined to metal parts, the results of bending fatigue testing as specified in JIS Z 2273 are presented.

[0182] Figure 9 This is an S-N line graph representing the results of a bending fatigue test. Figure 9 The S-N line diagram represents the number of repetitions required to break the copper pipe under a predetermined repetitive stress. The outer diameter, wall thickness, and length of each pipe in Examples 1 and 2, and Comparative Examples 1 and 2, are all equal.

[0183] The copper tube of Example 1 is formed from a copper alloy with the material designation C5010T-O and is heated to the same temperature as the brazing in the furnace. For example, the copper tube of Example 1 is heated in a furnace at a temperature of 1000°C to 1100°C for 20 to 30 minutes.

[0184] The copper tube in Example 2 was formed from a copper alloy with the material designation C1862T-O and was heated under the same conditions as in Example 1.

[0185] The copper tube of Comparative Example 1 was formed from standard copper with the material designation C1220T-O. The copper tube of Comparative Example 2 was formed from standard copper with the material designation C1220T-O and was heated under the same conditions as in Examples 1 and 2.

[0186] like Figure 9 As shown, the copper tubes of Examples 1 and 2, even after 1.0 × 10⁻⁶ cycles, n In this case, the stress at failure is also higher than the allowable stress σ1. Therefore, it can be concluded that the copper tubes of Examples 1 and 2 do not have strength problems even if they are heated by brazing in a furnace.

[0187] Furthermore, it can be seen that the decrease in strength of the copper tubes in Examples 1 and 2 is smaller relative to the increase in the number of repetitions compared to the copper tubes in Comparative Examples 1 and 2. It can be seen that at a repetition count of 1.0 × 10⁻⁶, the strength of the copper tubes in Examples 1 and 2 is significantly reduced. n In this case, the strength of the copper tube in Example 1 is close to that of the copper tube in Comparative Example 2 that was not heated.

[0188] Next, an example of the construction of the joint between the iron-based refrigerant piping and the copper pipe forming the refrigerant piping assembly will be described.

[0189] Figure 10 This diagram shows an example of the connection between an iron-based refrigerant pipe and a copper pipe. Figure 10 This describes the structure of a joint where the end of the iron-based refrigerant piping 11 (which is a metal component) and the end of the copper component 20 (which is different from the first metal component and the second metal component) are connected via the first copper pipe 13. Examples of the copper component 20 include the end of the copper-based refrigerant piping that forms the refrigerant circuit 10 and the end of the connection portion of the equipment that performs the refrigeration cycle.

[0190] like Figure 10 As shown, the first refrigerant piping 11, which is the first metal component of the iron system, can be connected to the copper component 20 forming the refrigerant circuit 10 via the first copper pipe 13. The copper component 20 is a copper alloy that is substantially free of one or more alloying elements selected from Co, Sn, Zn, Ni, Zr, and Fe through active addition, and the content of these alloying elements is lower than that in the first copper pipe 13. For example, conventionally used phosphorus-deoxidized copper pipes or copper alloy pipes composed of low alloys with fewer alloying elements and lower raw material costs can be used.

[0191] Preferably, an enlarged diameter portion 11a is formed at the end of the iron-based refrigerant pipe 11, the inner and outer diameters of which are larger than those of the main body. Additionally, an inner flange 13a is preferably formed at the end of the first copper pipe 13, protruding in a flange shape towards the center. The length along the centerline of the first copper pipe 13 is preferably shorter than the length along the centerline of the iron-based first refrigerant pipe 11 and the copper component 20.

[0192] Furthermore, the outer diameter of the first copper tube 13 is preferably smaller than the inner diameter of the expanded diameter portion 11a of the iron-based refrigerant piping 11. The inner diameter of the first copper tube 13 is preferably larger than the outer diameter of the copper component 20. Using such a first copper tube 13 allows it to be fitted into the expanded diameter portion 11a of the iron-based refrigerant piping 11. Additionally, the end of the copper component 20 can be fitted into the first copper tube 13.

[0193] The iron-based first refrigerant piping 11 and the copper component 20 are preferably connected by overlapping via a first copper pipe 13. With this configuration, even with a shortened length of the first copper pipe 13, a high-strength bond can be achieved between the iron-based first refrigerant piping 11 and the copper component 20. The iron-based first refrigerant piping 11 and the first copper pipe 13 are brazed in the furnace. The first copper pipe 13, bonded to the iron-based first refrigerant piping 11, and the copper component 20 can be joined by atmospheric brazing or the like. Because the length of the first copper pipe 13 can be shortened, the manufacturing cost of the refrigeration cycle unit can be further reduced.

[0194] also, Figure 10 The structure of the joint between the iron-based refrigerant piping and the copper pipe shown can also be formed in the iron-based oil separator 8a and the iron-based four-way valve 3a. Such a structure can be formed in a part of the joint in the refrigerant circuit 10 or in all the joints in the refrigerant circuit 10.

[0195] The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications are included as long as they do not depart from the scope of the technology. For example, the above-described embodiments are not necessarily limited to having all the structures described. In addition, it is possible to replace a part of the structure of a certain embodiment with other structures, or to add other structures to the structure of a certain embodiment. Furthermore, it is also possible to add other structures, delete structures, or replace structures in a part of the structure of a certain embodiment.

[0196] For example, in the embodiments described above, a receiver, a dryer, etc., may also be provided on the refrigerant circuit 10. The receiver, dryer, etc., constitute metal parts that can be connected to the assembly. Additionally, an injection circuit for injecting refrigerant at intermediate pressure into the compressor 2 may also be provided on the refrigerant circuit 10. The injection circuit bypasses the evaporator and is connected to the compressor 2. The injection circuit may also be formed by an assembly.

[0197] Furthermore, in the above embodiments, an air conditioner is shown as an example of a refrigeration cycle device, but the air conditioner can also be any of an indoor air conditioner, a cabinet air conditioner, a residential multi-split air conditioner, a commercial air conditioner, a commercial multi-split air conditioner, or a building multi-split air conditioner. In each figure, the outdoor unit 100 and the indoor unit 200 are connected one-to-one, but it is also possible for multiple outdoor units to be connected to one indoor unit, multiple indoor units to be connected to one outdoor unit, or multiple indoor units to be connected to multiple outdoor units.

[0198] Furthermore, in the above embodiments, an air conditioner is shown as an example of a refrigeration cycle device, but refrigeration equipment such as a freezer, refrigerator, freezer, or freezer-freezer can also be formed as a refrigeration cycle device. The structure of the components in the above embodiments can be applied to the refrigerant circuit of a refrigeration equipment having an outdoor unit. The refrigerant circuit of the refrigeration equipment is formed by connecting a compressor, a heat source-side heat exchanger disposed outside the unit, a pressure reducer such as a capillary tube, a gas-side stop valve, a liquid-side stop valve, and a utilization-side heat exchanger disposed inside the unit via refrigerant piping.

[0199] In refrigeration equipment, examples of first metal components include three-way valves, accumulators, oil separators, and refrigerant piping that forms a gas-side refrigerant circuit connecting a gas-side stop valve to a heat exchanger on the heat source side. Examples of second metal components include pressure regulators and refrigerant piping that forms a liquid-side refrigerant circuit connecting a heat exchanger on the heat source side to a liquid-side stop valve.

Claims

1. An outdoor unit of a refrigeration cycle apparatus, comprising a compressor, a heat exchanger on the heat source side, a pressure reducer, a gas-side preventive valve, and a liquid-side preventive valve, characterized in that the outdoor unit of the refrigeration cycle apparatus comprises: A first metal component is disposed at least in a gas-side refrigerant circuit that connects the gas-side shut-off valve and the heat source-side heat exchanger via the compressor. The second metal component is at least disposed in the liquid-side refrigerant circuit that connects the heat source-side heat exchanger and the liquid-side stop valve via the pressure reducer. A first copper tube, which is joined to the aforementioned first metal component; and The second copper tube is joined to the aforementioned second metal component. The aforementioned first metal component and the aforementioned second metal component are made of iron, iron alloy, or stainless steel. The first copper tube mentioned above is made of a copper alloy containing alloying elements. The second copper tube is made of copper without the aforementioned alloying elements, or is made of a copper alloy with a lower content of the aforementioned alloying elements than the first copper tube.

2. The outdoor unit of the refrigeration cycle device according to claim 1, characterized in that, The aforementioned first metal component is a refrigerant pipe, an oil separator, a part of an oil separator, a four-way valve, or a part of a four-way valve. The aforementioned second metal component is the outdoor unit of the refrigeration cycle device, which serves as the refrigerant piping.

3. An outdoor unit of a refrigeration cycle apparatus, comprising a compressor, a heat exchanger on the heat source side, a pressure reducer, a gas-side preventive valve, and a liquid-side preventive valve, characterized in that the outdoor unit of the refrigeration cycle apparatus comprises: A first metal component is disposed at least in a gas-side refrigerant circuit that connects the gas-side shut-off valve and the heat source-side heat exchanger via the compressor. Refrigerant piping, which is at least configured in a liquid-side refrigerant circuit connecting the heat source-side heat exchanger and the liquid-side check valve via the aforementioned pressure reducer; and The first copper tube is joined to the aforementioned first metal component. The aforementioned first metal component is made of iron, iron alloy, or stainless steel. The first copper tube mentioned above is made of a copper alloy containing alloying elements. The aforementioned refrigerant piping is made of copper without the aforementioned alloying elements, or of a copper alloy with a lower content of the aforementioned alloying elements than the aforementioned first copper pipe.

4. The outdoor unit of the refrigeration cycle device according to claim 3, characterized in that, The aforementioned first metal component is a refrigerant pipe, an oil separator, a metal component that forms part of an oil separator, a four-way valve, or a metal component that forms part of a four-way valve.

5. The outdoor unit of the refrigeration cycle apparatus according to any one of claims 1 to 4, characterized in that, The aforementioned alloying elements are one or more of P, Co, Sn, Zn, Ni, Zr, and Fe.

6. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, characterized in that, The first copper pipe is shorter than the refrigerant piping connected to it.

7. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, characterized in that, The first metal component mentioned above is a refrigerant pipe. The thickness of the first copper tube is greater than the thickness of the refrigerant piping, which is the first metal component.

8. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, characterized in that, The first metal component mentioned above is a refrigerant pipe. The aforementioned second metal component is a refrigerant pipe. The thickness of the first copper tube is greater than the thickness of the refrigerant piping, which is the first metal component, and the thickness of the refrigerant piping, which is the second metal component.

9. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, characterized in that, It is equipped with one or more of the following: an energy storage device, an oil separator, and a four-way valve. The aforementioned first metal component is a refrigerant piping connecting the compressor and the energy storage unit, the compressor and the oil separator, or the compressor and the four-way valve. The compressors mentioned above are scroll compressors or dual rotary compressors.

10. The outdoor unit of the refrigeration cycle apparatus according to any one of claims 1 to 4, characterized in that, The content of the alloying element in the first copper tube is lower than that in the first metal component.

11. The outdoor unit of the refrigeration cycle apparatus according to claim 1 or 3, characterized in that, The first metal component mentioned above is a refrigerant pipe. The first copper tube is connected to the copper component that forms the refrigerant circuit. The aforementioned copper components are made of copper without the aforementioned alloying elements, or of a copper alloy with a lower content of the aforementioned alloying elements than the aforementioned first copper tube.

12. The outdoor unit of the refrigeration cycle apparatus according to claim 11, characterized in that, The aforementioned refrigerant piping overlaps with the aforementioned copper components via the aforementioned first copper pipe.

13. A refrigeration cycle device comprising an outdoor unit and an indoor unit, the outdoor unit including a compressor, a heat exchanger on the heat source side, a pressure reducer, a gas-side preventive valve, and a liquid-side preventive valve. The aforementioned refrigeration cycle device is characterized by having: A first metal component is disposed at least in a gas-side refrigerant circuit that connects the gas-side shut-off valve and the heat source-side heat exchanger via the compressor. The second metal component is at least disposed in the liquid-side refrigerant circuit that connects the heat source-side heat exchanger and the liquid-side stop valve via the pressure reducer, or in the utilization-side refrigerant circuit that is built into the indoor unit as a refrigerant circuit. A first copper tube, which is joined to the aforementioned first metal component; and The second copper tube is joined to the aforementioned second metal component. The aforementioned first metal component and the aforementioned second metal component are made of iron, iron alloy, or stainless steel. The first copper tube mentioned above is made of a copper alloy containing alloying elements. The second copper tube is made of copper without the aforementioned alloying elements, or is made of a copper alloy with a lower content of the aforementioned alloying elements than the first copper tube.

14. A refrigeration cycle device comprising an outdoor unit and an indoor unit, the outdoor unit including a compressor, a heat exchanger on the heat source side, a pressure reducer, a gas-side preventive valve, and a liquid-side preventive valve. The aforementioned refrigeration cycle device is characterized by having: A first metal component is disposed at least in a gas-side refrigerant circuit that connects the gas-side shut-off valve and the heat source-side heat exchanger via the compressor. Refrigerant piping, which is at least configured in a liquid-side refrigerant circuit connecting the heat source-side heat exchanger and the liquid-side stop valve via the aforementioned pressure reducer, or in a utilization-side refrigerant circuit built into the aforementioned indoor unit as a refrigerant circuit; and The first copper tube is joined to the aforementioned first metal component. The aforementioned first metal component is made of iron, iron alloy, or stainless steel. The first copper tube mentioned above is made of a copper alloy containing alloying elements. The aforementioned refrigerant piping is made of copper without the aforementioned alloying elements, or of a copper alloy with a lower content of the aforementioned alloying elements than the aforementioned first copper pipe.

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