Patent Application
20220146163
The present disclosure relates to a refrigerant cycle apparatus.
In consideration of environmental loads, a refrigerant having a relatively small ozone depletion potential (ODP) and a refrigerant having a relatively small global warming potential (GWP) have been considered.
For example, in PTL 1 (Japanese Unexamined Patent Application Publication No. 2017-149943), a refrigerant with which it is possible to suppress the ozone depletion potential and the global warming potential to be small has been considered.
A refrigerant cycle apparatus according to a first aspect is a refrigerant cycle apparatus including a refrigerant circuit. The refrigerant circuit is constituted by a compressor, an expansion valve, and a heat exchanger that are connected to each other. In the refrigerant circuit, a refrigerant containing CF3I circulates. The refrigerant circuit includes a component to be in contact with the refrigerant. At least a surface of the component to be in contact with the refrigerant is constituted by a corrosion resistance material that contains at least one or more selected from the group consisting of a metal in which the percentage of zinc is 10 wt % or less, a resin other than nylon 66, and carbon.
Hereinafter, an air conditioning apparatus 1 as a refrigeration cycle apparatus according to the present embodiment will be described with reference to
(1) Overview of Air Conditioning Apparatus 1
The air conditioning apparatus 1 is an apparatus that conditions air in a target space by performing a vapor compression refrigeration cycle.
The air conditioning apparatus 1 includes, mainly, an outdoor unit 2, an indoor unit 3, a liquid refrigerant connection pipe 6 and a gas refrigerant connection pipe 5 that connect the outdoor unit 2 and the indoor unit 3 to each other, and a controller 7 that controls the operation of the air conditioning apparatus 1.
In the air conditioning apparatus 1, a refrigeration cycle in which, after a refrigerant enclosed in a refrigerant circuit 10 is compressed and condenses, or releases heat, is decompressed, and evaporates, the refrigerant is compressed again is performed. In the present embodiment, the refrigerant circuit 10 is filled with a refrigerant for performing a vapor compression refrigeration cycle.
(Refrigerant)
As the refrigerant with which the refrigerant circuit 10 is filled, a refrigerant constituted by only CF3I or a mixture refrigerant containing CF3I is usable. As such a refrigerant, for example, a refrigerant such as R466A or the like is usable as a refrigerant containing R32, R125, and CF3I. Here, although not limited, the content of CF3I in the refrigerant may be, for example, 5 wt % or more and 70 wt % or less and is preferably 20 wt % or more and 50 wt % or less. Here, the refrigerant containing CF3I is preferable in that flammability is low and that the values of both of ozone depletion potential (ODP) and global warming potential (GWP) are easily balanced with low values.
(Refrigerating-Machine Oil)
A refrigerating-machine oil is enclosed together with the refrigerant in the refrigerant circuit 10. The refrigerating-machine oil used together with the refrigerant is preferably an ether oil or an ester oil. As examples of the ether oil, there are presented, for example, a polyvinyl ether oil, a polyoxyalkylene oil, and the like. As examples of the ester oil, there are presented, for example, a dibasic acid ester oil of dibasic acid and monohydric alcohol, a polyol ester oil of polyol and fatty acid or a complex ester oil of polyol, polybasic acid, and monohydric alcohol (or fatty acid), a polyol carbonic acid ester oil, and the like. One type of a refrigerating-machine oil may be individually used, or two or more types of refrigerating-machine oils may be combined together and used.
These refrigerating-machine oils can contain, as an additive agent, at least one or more selected from the group consisting of an extreme pressure agent, an acid scavenger, and an antioxidant. These additive agents are each preferably blended at, for example, 3 wt % or less in the refrigerating-machine oil. In particular, with regard to the acid scavenger in the refrigerating-machine oil, it is preferable that concentration thereof be 1.0 wt % or more. By regulating the blending amounts of the antioxidant and the acid scavenger, it becomes easy to regulate the moisture content in a fluid containing a refrigerant and a refrigerating-machine oil.
As examples of the extreme pressure agent, there are presented, for example, an extreme pressure agent containing phosphoric acid esters; extreme pressure agents based on organosulfur compounds such as monosulfides, polysulfides, sulfoxides, sulfones, thiosulfinates, sulfurized fats and oils, thiocarbonates, thiophenes, thiazoles, and methanesulfonic acid esters; extreme pressure agents based on thiophosphoric acid esters such as thiophosphoric acid triesters; extreme pressure agents based on esters such as higher fatty acids, hydroxyaryl fatty acids, polyhydric alcohol esters, and acrylic acid esters; extreme pressure agents based on organochlorine compounds such as chlorinated hydrocarbons, e.g., chlorinated paraffin and chlorinated carboxylic acid derivatives; extreme pressure agents based on fluoroorganic compounds such as fluorinated aliphatic carboxylic acids, fluorinated ethylene resins, fluorinated alkylpolysiloxanes, and fluorinated graphites; extreme pressure agents based on alcohols such as higher alcohols; and extreme pressure agents based on metal compounds such as naphthenic acid salts (e.g., lead naphthenate), fatty acid salts (e.g., lead fatty acid), thiophosphoric acid salts (e.g., zinc dialkyldithiophosphate), thiocarbamic acid salts, organomolybdenum compounds, organotin compounds, organogermanium compounds, and boric acid esters.
As the acid scavenger, epoxy compounds such as phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, cyclohexene oxide, α-olefin oxide, and epoxidized soybean oil; carbodiimides; and the like are usable. Among these, phenyl glycidyl ether, alkyl glycidyl ether, alkylene glycol glycidyl ether, cyclohexene oxide, α-olefin oxide are preferable from the point of view of compability. The carbon number may be 3 or more and 30 or less and are more preferably 4 or more and 24 or less. The total carbon number of α-olefin oxide may be 4 or more and 50 or less and are more preferably 4 or more and 24 or less. As the acid scavenger, only one type of an acid scavenger may be used, and a plurality of types of acid scavengers can be used in combination.
As the antioxidant, for example, a phenol-based antioxidant and an amine-based antioxidant are usable. Examples of the phenol-based antioxidant include 2,6-di-tert-butyl-4-methylphenol (DBPC), 2,6-di-tert-butyl-4-ethylphenol, 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-buthylphenol, di-tert-butyl-p-cresol, bisphenol A, and the like. Examples of the amine-based antioxidant include N,N′-diisopropyl-p-phenylenediamine, N,N′-di-sec-butyl-p-phenylenediamine, phenyl-a-naphthylamine, N,N′-di-phenyl-p-phenylenediamine, and N,N- di(2-naphthyl)-p-phenylenediamine, and the like.
The moisture content in the refrigerant circuit 10 is preferably 500 ppm or less from the point of view of suppressing decomposition of the refrigerant containing CF3I. The moisture content in a case of a fluid that flows through an outlet of a heat exchanger (an indoor heat exchanger 18 or an outdoor heat exchanger 13) that functions as a refrigerant condenser is preferably 500 ppm or less.
The air amount in a fluid that flows in the refrigerant circuit 10 is preferably 10 Torr or less from the point of view of suppressing decomposition of the refrigerant containing CF3I.
(1-1) Outdoor Unit 2
The outdoor unit 2 is connected to the indoor unit 3 via the liquid refrigerant connection pipe 6 and the gas refrigerant connection pipe 5 and constitutes part of the refrigerant circuit 10. The outdoor unit 2 includes, mainly, a compressor 11, a four-way switching valve 12, an outdoor heat exchanger 13, an expansion valve 9, a low-pressure receiver 14, an outdoor fan 15, a liquid-side shutoff valve 17, and a gas-side shutoff valve 16.
The compressor 11 is an apparatus that compresses a low-pressure refrigerant in the refrigeration cycle to a high pressure. As the compressor 11, for example, a compressor in which a compression element of a rotary type, a scroll type, or the like is driven to rotate by a compressor motor is usable. Details of the compressor 11 of the present embodiment will be described later. The compressor motor is for changing capacity, and the operation frequency of the compressor motor can be controlled by an inverter.
The four-way switching valve 12 is switchable by switching the connection state in the refrigerant circuit 10 between a first connection state (refer to the solid lines in
The outdoor heat exchanger 13 is a heat exchanger that functions as a condenser or a radiator for a high-pressure refrigerant in the refrigeration cycle in cooling operation and functions as an evaporator for a low-pressure refrigerant in the refrigeration cycle in heating operation. The outdoor heat exchanger 13 includes a plurality of heat transfer tubes (not illustrated) in which the refrigerant flows, and a plurality of heat transfer fins (not illustrated) with a gap therebetween in which air flows. The plurality of heat transfer tubes are arranged in the up-down direction, and each heat transfer tube extends substantially in the horizontal direction. The heat transfer tubes are constituted by a metal in which the percentage of zinc is 10 wt % or less and, more preferably, by a metal in which the percentage of zinc is 5 wt % or less. As the metal, for example, there are presented copper, a copper alloy, iron, an iron-containing alloy, stainless steel, and the like. The plurality of heat transfer fins extending in the up-down direction are arranged to be spaced from each other at a predetermined interval in a direction in which the heat transfer tubes extend. The plurality of heat transfer fins and the plurality of heat transfer tubes are combined together such that each heat transfer fin passes through the plurality of heat transfer tubes.
The outdoor fan 15 generates an air flow for supplying outdoor air to the outdoor heat exchanger 13 in the outdoor unit 2 and, after causing the outdoor air to exchange heat with the refrigerant in the outdoor heat exchanger 13, discharging the outdoor air to the outside of the outdoor unit 2. The outdoor fan 15 is driven to rotate by an outdoor fan motor.
The expansion valve 9 is provided between the liquid-side end portion of the outdoor heat exchanger 13 and the liquid-side shutoff valve 17. The expansion valve 9 is, for example, an electronic expansion valve whose valve opening degree is adjustable by control. Details of the expansion valve 9 will be described later.
The low-pressure receiver 14 is provided between the suction side of the compressor 11 and one of the connection ports of the four-way switching valve 12 and is a refrigerant container capable of storing, as a liquid refrigerant, a surplus refrigerant in the refrigerant circuit 10.
The liquid-side shutoff valve 17 is a manual valve that is disposed at a part of the outdoor unit 2 connected to the liquid refrigerant connection pipe 6.
The gas-side shutoff valve 16 is a manual valve that is disposed at a part of the outdoor unit 2 connected to the gas refrigerant connection pipe 5.
The outdoor unit 2 includes an outdoor-unit control unit 71 that controls the operation of each component constituting the outdoor unit 2. The outdoor-unit control unit 71 includes a microcomputer including a CPU, a memory, and the like. The outdoor-unit control unit 71 is connected to an indoor-unit control unit 72 of each indoor unit 3 via a communication line, and transmits and receives a control signal and the like.
The outdoor unit 2 is provided with a discharge temperature sensor 75, a suction temperature sensor 76, an outdoor heat-exchange temperature sensor 77, an outside-air temperature sensor 78, and the like. Each of these sensors is electrically connected to the outdoor-unit control unit 71 and transmits a detection signal to the outdoor-unit control unit 71. The discharge temperature sensor 75 detects the temperature of the refrigerant that flows in a discharge pipe 4d connecting the discharge side of the compressor 11 to the fourth connection port 54, which is one of the connection ports of the four-way switching valve 12. The suction temperature sensor 76 detects the temperature of the refrigerant that flows in, among suction flow paths connecting the suction side of the compressor 11 to one of the connection ports of the four-way switching valve 12, a suction pipe 4e extending from the low-pressure receiver 14 to the suction side of the compressor 11. The outdoor heat-exchange temperature sensor 77 detects the temperature of the refrigerant that flows through an outlet of the outdoor heat exchanger 13 on the liquid side, which is a side opposite to the side where a third pipe 4c is connected. The outside-air temperature sensor 78 detects the temperature of outside air that has not passed through the outdoor heat exchanger 13 yet.
(1-2) Indoor Unit 3
The indoor unit 3 is installed on a wall surface, a ceiling, or the like inside a room that is a target space. The indoor unit 3 is connected to an outdoor unit 2 via the liquid refrigerant connection pipe 6 and the gas refrigerant connection pipe 5 and constitutes part of the refrigerant circuit 10.
The indoor unit 3 includes the indoor heat exchanger 18 and an indoor fan 19.
The indoor heat exchanger 18 is connected at the liquid side to the liquid refrigerant connection pipe 6 and connected at the gas-side end to the gas refrigerant connection pipe 5. The indoor heat exchanger 18 is a heat exchanger that functions as an evaporator for a low-pressure refrigerant in the refrigeration cycle in cooling operation and functions as a condenser or a radiator for a high-pressure refrigerant in the refrigeration cycle in heating operation.
The indoor fan 19 generates an air flow for suctioning air in a room that is an air-conditioning target space into the indoor unit 3 and, after causing the air to exchange heat with the refrigerant in the indoor heat exchanger 18, discharging the air to the outside of the indoor unit 3. The indoor fan 19 is driven to rotate by an indoor fan motor.
The indoor unit 3 includes the indoor-unit control unit 72 that controls the operation of each component constituting the indoor unit 3. The indoor-unit control unit 72 includes a microcomputer including a CPU, a memory, and the like. The indoor-unit control unit 72 is connected to the outdoor-unit control unit 71 via a communication line, and transmits and receives a control signal and the like.
The indoor unit 3 is provided with an indoor liquid-side heat-exchange temperature sensor 73, an indoor-air temperature sensor 74, and the like. Each of these sensors is electrically connected to the indoor-unit control unit 72 and transmits a detection signal to the indoor-unit control unit 72. The indoor liquid-side heat-exchange temperature sensor 73 detects the temperature of the refrigerant that flows through an outlet of the indoor heat exchanger 18 on the liquid side, which is a side opposite to the side where the gas refrigerant connection pipe 5 is connected. The indoor-air temperature sensor 74 detects the temperature of indoor air that has not passed through the indoor heat exchanger 18 yet.
(1-3) Controller 7
In the air conditioning apparatus 1, the outdoor-unit control unit 71 and the indoor-unit control unit 72 are connected to each other via a communication line and thereby constitute the controller 7 that controls the operation of the air conditioning apparatus 1.
The controller 7 includes, mainly, a CPU (central processing unit) and a memory such as a ROM, a RAM, or the like. Components included in the outdoor-unit control unit 71 and/or the indoor-unit control unit 72 integrally function to thereby implement various processing and control by the controller 7.
Preferably, the controller 7 controls constituents of the refrigerant circuit 10 such that the maximum temperature of a portion of the air conditioning apparatus 1 to be in contact with a fluid that flows in the refrigerant circuit 10 becomes, for example, 100° C. or less. As such control, for example, there are presented control in which the drive frequency of the compressor 11 is controlled not to become a predetermined value or more, control in which the temperature of the refrigerant discharged from the compressor 11 is controlled not to become a predetermined temperature or more, control in which the pressure of a refrigerant discharged from the compressor 11 is controlled not to become a predetermined pressure or more, and the like. Here, the control in which the temperature of the refrigerant discharged from the compressor 11 is controlled not to become a predetermined temperature or more and the like may be implemented by decreasing the drive frequency of the compressor 11 and/or by increasing the valve opening degree of the expansion valve 9. Through the above control, decomposition of the refrigerant containing CF3I is suppressed, and, consequently, it is possible to suppress corrosion effectively.
(1-4) Remote Controller 70
A remote controller 70 is disposed in a room that is an air-conditioning target space or in a specific space of a building including an air-conditioning target space and used by a user or the like to perform monitoring of the operation control instruction and the operation state of the air conditioning apparatus 1.
The remote controller 70 includes a reception portion 70a such as an operation button, a touch panel, or the like for receiving an input of information by being operated by a user or the like, and a display 70b capable of displaying various information. The remote controller 70 is connected to the outdoor-unit control unit 71 and the indoor-unit control unit 72 via a communication line and capable of supplying information received by the reception portion 70a from a user to the controller 7. Information received from the controller 7 can be output at the display 70b.
Although not limited, information received from a user or the like by the reception portion 70a includes various information on an instruction for executing a cooling operating mode, an instruction for executing a heating operating mode, an instruction for stopping operation, specification of a set temperature, and the like. Although not limited, information displayed on the display 70b includes information and the like indicating a current state (cooling or heating) of the operating mode, a set temperature, and occurrence of various abnormalities.
(2) Structure of Compressor 11
As the compressor 11, for example, a scroll compressor, such as that illustrated in
This compressor 11 includes a casing 20, a scroll compression mechanism 21, a drive motor 24, a crankshaft 25, a lower bearing 26, and a balance weight 30.
The casing 20 includes a substantially cylindrical cylinder member 20a that opens at the upper and lower ends, and an upper cover 20b and a lower cover 20c that are provided at the upper end and the lower end of the cylinder member 20a, respectively. The cylinder member 20a is fixed to the upper cover 20b and the lower cover 20c airtightly by welding. In the casing 20, constituent devices of the compressor 11 including the scroll compression mechanism 21, the drive motor 24, the crankshaft 25, and the lower bearing 26 are housed. An oil reservoir space So is formed in a lower portion of the casing 20. In the oil reservoir space So, a refrigerating-machine oil O for lubricating the scroll compression mechanism 21 and the like is stored. At an upper portion of the casing 20, the suction pipe 4e through which a low-pressure gas refrigerant of the refrigeration cycle of the refrigerant circuit 10 is sucked and a gas refrigerant is supplied to the scroll compression mechanism 21 is provided to extend through the upper cover 20b. The lower end of the suction pipe 4e is connected to a fixed scroll 22 of the scroll compression mechanism 21. The suction pipe 4e is in communication with a compression chamber Sc, which will be described later, of the scroll compression mechanism 21. At an intermediate portion of the cylinder member 20a of the casing 20, the discharge pipe 4d through which a refrigerant to be discharged to the outside of the casing 20 passes is provided. The discharge pipe 4d is disposed such that an end portion of the discharge pipe 4d in the inside of the casing 20 projects in a high-pressure space Sh formed below a housing 27 of the scroll compression mechanism 21. In the discharge pipe 4d, a high-pressure refrigerant of the refrigeration cycle after compression by the scroll compression mechanism 21 flows.
The scroll compression mechanism 21 includes, mainly, the housing 27, the fixed scroll 22 disposed above the housing 27, and a movable scroll 23 that forms the compression chamber Sc by being combined with the fixed scroll 22.
The fixed scroll 22 includes a tabular fixed-side panel 22a, a spiral fixed-side lap 22b projecting from the front surface of the fixed-side panel 22a, and an outer edge portion 22c that surrounds the fixed-side lap 22b. At a center portion of the fixed-side panel 22a, a discharge port 22d having a noncircular shape and in communication with the compression chamber Sc of the scroll compression mechanism 21 is formed to extend through the fixed-side panel 22a in the thickness direction. The refrigerant compressed in the compression chamber Sc is discharged through the discharge port 22d, passes through a refrigerant passage, which is not illustrated, formed in the fixed scroll 22 and the housing 27, and flows into the high-pressure space Sh.
The movable scroll 23 includes a tabular movable-side panel 23a, a spiral movable-side lap 23b projecting from the front surface of the movable-side panel 23a, and a boss portion 23c having a cylindrical shape and projecting from the back surface of the movable-side panel 23a. The fixed-side lap 22b of the fixed scroll 22 and the movable-side lap 23b of the movable scroll 23 are combined together in a state in which the lower surface of the fixed-side panel 22a and the upper surface of the movable-side panel 23a face each other. The compression chamber Sc is formed between the fixed-side lap 22b and the movable-side lap 23b that are adjacent to each other. In response to the movable scroll 23 revolving with respect to the fixed scroll 22 as described later, the volume of the compression chamber Sc periodically changes, and suction, compression, and discharging of the refrigerant are performed in the scroll compression mechanism 21. The boss portion 23c is a cylindrical part whose upper end is closed. An eccentric portion 25b, which will be described later, of the crankshaft 25 is inserted into a hollow portion of the boss portion 23c, and the movable scroll 23 and the crankshaft 25 are thereby coupled to each other. The boss portion 23c is disposed in an eccentric-portion space 28 formed between the movable scroll 23 and the housing 27. The eccentric-portion space 28 is in communication with the high-pressure space Sh via an oil supply path 39, which will be described later, of the crankshaft 25, and the like, and a high pressure acts on the eccentric-portion space 28. The lower surface of the movable-side panel 23a in the eccentric-portion space 28 is pressed upwardly by this pressure toward the fixed scroll 22. Due to this force, the movable scroll 23 comes into close contact with the fixed scroll 22. The movable scroll 23 is supported by the housing 27 via an oldham ring 29 disposed in an “oldham ring space Sr”. The oldham ring 29 is a member that prevents the movable scroll 23 from rotating on its axis and causes the movable scroll 23 to revolve. By using the oldham ring 29, when the crankshaft 25 rotates, the movable scroll 23 coupled at the boss portion 23c to the crankshaft 25 revolves with respect to the fixed scroll 22 without rotating on its axis, and the refrigerant in the compression chamber Sc is compressed.
The housing 27 is press-fitted to the inner side of the cylinder member 20a and fixed at the entirety of the outer peripheral surface thereof in the circumferential direction to the cylinder member 20a. The housing 27 and the fixed scroll 22 are fixed to each other by a bolt or the like, which is not illustrated, such that the upper end surface of the housing 27 is in close contact with the lower surface of the outer edge portion 22c of the fixed scroll 22. At the housing 27, a concave portion 27a disposed to be recessed at a center portion of the upper surface and an upper bearing portion 27b disposed below the concave portion 27a are formed. The concave portion 27a surrounds a side surface of the eccentric-portion space 28 in which the boss portion 23c of the movable scroll 23 is disposed. At the upper bearing portion 27b, an upper bearing 35 that is a cylindrical metal member pivotably supporting a main shaft 25a of the crankshaft 25 is disposed. The upper bearing 35 rotatably supports the main shaft 25a inserted into the upper bearing 35. In addition, the oldham ring space Sr in which the oldham ring 29 is disposed is formed in the housing 27.
The drive motor 24 includes an annular stator 33 fixed to the inner wall surface of the cylinder member 20a, and, on the inner side of the stator 33, a rotor 32 that is rotatably housed with a slight gap (air gap passage). The stator 33 is configured to include a coil. The rotor 32 is coupled to the movable scroll 23 via the crankshaft 25 disposed to extend in the up-down direction along the axis of the cylinder member 20a. The rotor 32 rotates and thereby causes the movable scroll 23 to revolve with respect to the fixed scroll 22.
The crankshaft 25 transmits the driving force of the drive motor 24 to the movable scroll 23. The crankshaft 25 is disposed to extend in the up-down direction along the axis of the cylinder member 20a and couples the rotor 32 of the drive motor 24 and the movable scroll 23 of the scroll compression mechanism 21 to each other. The crankshaft 25 includes the main shaft 25a whose center axis is coincident with the axis of the cylinder member 20a, and the eccentric portion 25b eccentric to the axis of the cylinder member 20a. The eccentric portion 25b is inserted into the boss portion 23c of the movable scroll 23 as described above. A pin bearing 31 that is a cylindrical metal member pivotably supporting the eccentric portion 25b is provided on the outer side of the eccentric portion 25b in the radial direction. The main shaft 25a is rotatably supported by the pin bearing 31, the upper bearing 35 of the upper bearing portion 27b of the housing 27, and the lower bearing 26, which will be described later. The main shaft 25a is coupled between the upper bearing 35 and the lower bearing 26 to the rotor 32 of the drive motor 24. In the inside of the crankshaft 25, the oil supply path 39 for supplying the refrigerating-machine oil O to the scroll compression mechanism 21 and the like is formed. The lower end of the main shaft 25a is positioned in the oil reservoir space So formed in the lower portion of the casing 20, and the refrigerating-machine oil O of the oil reservoir space So is supplied through the oil supply path 39 to the scroll compression mechanism 21 and the like.
The balance weight 30 is an annular member separated from the crankshaft 25 and is fitted to the main shaft 25a. The balance weight 30 includes a cylindrical part 30a and an eccentric part 30b formed at a portion of the cylindrical part 30a in the circumferential direction. The cylindrical part 30a has a centroid present on the axis of the crankshaft 25 and has a circular shape as viewed in the axial direction. The centroid of the eccentric part 30b is eccentric from the axis of the crankshaft 25 and, specifically, is eccentric from the axis of the crankshaft 25 in a predetermined direction. Consequently, the centroid of the entirety of the balance weight 30 is also eccentric from the axis of the crankshaft 25 in a predetermined direction. As described above, the movable scroll 23 is slidably supported at a portion thereof in the vicinity of the center by the eccentric portion 25b of the crankshaft 25. Consequently, the movable scroll 23 is also eccentric in the same direction as the eccentric portion 25b. With the above structure, it is possible to balance with the movable scroll 23 by disposing the balance weight 30 at the main shaft 25a with the predetermined direction directed opposite to the eccentric direction of the eccentric portion 25b. It is thus possible to prevent rocking of the crankshaft 25.
The lower bearing 26 is disposed below the drive motor 24. The lower bearing 26 is fixed on the inner side and below the cylinder member 20a. The lower bearing 26 is a cylindrical metal member that constitutes the bearing on the lower end side of the crankshaft 25 and that supports the main shaft 25a of the crankshaft 25 rotatably.
Next, the operation of the compressor 11 will be described.
When the drive motor 24 is started, the rotor 32 rotates with respect to the stator 33, and the crankshaft 25 fixed to the rotor 32 rotates. When the crankshaft 25 rotates, the movable scroll 23 coupled to the crankshaft 25 revolves with respect to the fixed scroll 22. Then, a low-pressure gas refrigerant in the refrigeration cycle is sucked into the compression chamber Sc from the peripheral edge side of the compression chamber Sc through the suction pipe 4e. In response to the movable scroll 23 revolving, the suction pipe 4e and the compression chamber Sc become not in communication with each other. Then, in response to a decrease in the capacity of the compression chamber Sc, the pressure of the compression chamber Sc starts to increase.
The refrigerant in the compression chamber Sc is compressed in response to the capacity of the compression chamber Sc decreasing and eventually becomes a high-pressure gas refrigerant. The high-pressure gas refrigerant is discharged through the discharge port 22d positioned near the center of the fixed-side panel 22a. Thereafter, the high-pressure gas refrigerant passes through a refrigerant passage, which is not illustrated, formed in the fixed scroll 22 and the housing 27 and flows into the high-pressure space Sh. The high-pressure gas refrigerant of the refrigeration cycle that has flowed into the high-pressure space Sh after compressed by the scroll compression mechanism 21 is discharged from the discharge pipe 4d.
In the above compressor 11, in particular, at least any one of the pin bearing 31, the upper bearing 35, the lower bearing 26, the balance weight 30, the movable scroll 23, the fixed scroll 22, the oldham ring 29, and the crankshaft 25 is preferably constituted by a metal in which the percentage of zinc is 10 wt % or less and more preferably constituted by a metal in which the percentage of zinc is 5 wt % or less.
In particular, since the density and the specific gravity of the balance weight 30 are large, from the point of view of downsizing, excellent workability, and favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product thereof, the balance weight 30 is preferably constituted by a copper alloy in which the percentage of zinc is 5 wt % of less and more preferably constituted by a copper alloy in which the percentage of zinc is 5 wt % or less and in which 0.2 wt % or more and 1.0 wt % or less of tin or aluminum is contained. When the balance weight 30 is constituted by a metal that differs from a copper alloy, stainless steel such as SUS304 or the like is preferable.
The pin bearing 31, the upper bearing 35, and the lower bearing 26 are preferably constituted by any of carbon, a polyimide resin, and a polyamidimide resin from the point of view of low friction properties, low abrasion properties, excellent workability, and favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product thereof.
(3) Structure of Expansion Valve 9
As the expansion valve 9, for example, an electronic expansion valve, such as that illustrated in
This expansion valve 9 includes, mainly, a coil 91, a rotor 92, the valve body 93, a casing 94, a valve sheet member 95, and the like.
The coil 91 is provided in the circumferential direction when the longitudinal direction of the valve body 93 is considered as the axial direction.
The rotor 92 is driven to rotate by the coil 91. The rotor 92 moves in a screw axis direction by rotating.
The valve body 93 is constituted by a shaft 93a and the needle 93b. The shaft 93a has a cylindrical shape and extends vertically. One end of the shaft 93a is attached to the rotor 92 to be coaxial therewith. The shaft 93a moves together with the rotor 92 in the axial direction. The needle 93b is provided at the lower end of the shaft 93a to have a conical shape directed downward. The needle 93b projects in a valve-body-side space 96, which will be described later.
The coil 91, the rotor 92, the shaft 93a of the valve body 93, and the like are housed in the inside of the casing 94.
The valve sheet member 95 is provided below the casing 94. The valve seat member 95 includes a first coupling portion 97, a second coupling portion 98, a valve-body-side space 96 for causing the first coupling portion 97 and the second coupling portion 98 to be in communication with each other, and a valve seat 99 provided between the valve-body-side space 96 and the first coupling portion 97. The valve seat 99 has a funnel shape to face the needle 93b of the valve body 93 from below on the outer side in the radial direction.
Thus, a high-pressure liquid refrigerant that has flowed in from the first coupling portion 97 or the second coupling portion 98 is decompressed by passing through a gap between the needle 93b and the valve seat 99. The degree of decompression at this time is regulated by changing the size of the gap between the needle 93b and the valve seat 99 by moving the valve body 93 forward and rearward by the rotation of the rotor 92.
The valve body 93 including the needle 93b can be constituted by a copper alloy in which the percentage of zinc is 10 wt % or less, is preferably constituted by a copper alloy in which the percentage of zinc is 5 wt % or less, and is more preferably constituted by a copper alloy in which the percentage of zinc is 5 wt % or less and in which 0.2 wt % or more and 1.0 wt % or less of tin or aluminum is contained, from the point of view of excellent erosion resistance, corrosion resistance and favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product thereof. When the valve body 93 including the needle 93b is constituted by a metal that differs from a copper alloy, stainless steel such as SUS304 or the like is preferable.
(4) Structure of Four-Way Switching Valve 12
As illustrated in
The four-way switching valve body 50 includes four connection ports including the first connection port 51, the second connection port 52, the third connection port 53, and the fourth connection port 54, a valve body 57, a first chamber 55, a second chamber 56, a first communication portion 55a, a second communication portion 56a, a high-pressure extraction portion 54a, and a low-pressure extraction portion 51a.
The discharge pipe 4d extending from the discharge side of the compressor 11 is connected to the fourth connection port 54 of the four-way switching valve body 50. A first pipe 4a extending from the low-pressure receiver 14 is connected to the first connection port 51 of the four-way switching valve body 50. A second pipe 4b extending from the gas-side shutoff valve 16 is connected to the second connection port 52 of the four-way switching valve body 50. The third pipe 4c extending from the gas-side end portion of the outdoor heat exchanger 13 is connected to the third connection port 53 of the four-way switching valve body 50.
In the first connection state of the four-way switching valve body 50, the valve body 57 is positioned at a first location so that the fourth connection port 54 and the third connection port 53 are in communication with each other while the second connection port 52 and the first connection port 51 are in communication with each other. Consequently, in the first connection state, the refrigerant discharged from the discharge side of the compressor 11 flows through the discharge pipe 4d, the fourth connection port 54, the third connection port 53, and the third pipe 4c sequentially and is supplied to the gas-side end portion of the outdoor heat exchanger 13. In the first connection state, the refrigerant that has sent from the gas refrigerant connection pipe 5 via the gas-side shutoff valve 16 to the second pipe 4b flows through the second connection port 52, the first connection port 51, the first pipe 4a, the low-pressure receiver 14, and the suction pipe 4e and is sent to the suction side of the compressor 11.
In the second connection state of the four-way switching valve 50, the valve body 57 is positioned at a second location so that the fourth connection port 54 and the second connection port 52 are in communication with each other while the third connection port 53 and the first connection port 51 are in communication with each other. Consequently, in the second connection state, the refrigerant discharged from the discharge side of the compressor 11 flows through the discharge pipe 4d, the fourth connection port 54, the second connection port 52, and the second pipe 4b sequentially and is sent to the gas refrigerant connection pipe 5 via the gas-side shutoff valve 16. In the second state, the refrigerant that has passed through the gas-side end portion of the outdoor heat exchanger 13 flows through the third pipe 4c, the third connection port 53, the first connection port 51, the first pipe 4a, the low-pressure receiver 14, and the suction pipe 4e sequentially and is sent to the suction side of the compressor 11.
The valve body 57 is positioned between the first chamber 55 and the second chamber 56 in the inside of the four-way switching valve body 50. The valve body 57 is provided to partition a space on the side of the first connection port 51 and a space on the side of the fourth connection port 54 from each other. The valve body 57 moves by sliding in response to a pressure that acts on the first chamber 55 and the second chamber 56. Specifically, in a state in which a low pressure acts on the first chamber 55 and a high pressure acts on the second chamber 56, the valve body 57 moves by sliding such that the first chamber 55 becomes smaller and the second chamber 56 becomes larger, thereby making a state in which the fourth connection port 54 and the third connection port 53 are in communication with each other while the second connection port 52 and the first connection port 51 are in communication with each other. In a state in which a high pressure acts on the first chamber 55 and a low pressure acts on the second chamber 56, the valve body 57 moves by sliding such that the first chamber 55 becomes larger and the second chamber 56 becomes smaller, thereby making a state in which the fourth connection port 54 and the second connection port 52 are in communication with each other while the third connection port 53 and the first connection port 51 are in communication with each other.
The first chamber 55 is provided with the first communication portion 55a. A first pilot pipe 62a that is a capillary tube extending from the pilot electromagnetic valve 60 is connected to the first communication portion 55a. Consequently, a refrigerant pressure of the first pilot pipe 62a acts on the first chamber 55.
The second chamber 56 is provided with the second communication portion 56a. A second pilot pipe 63a that is a capillary tube extending from the pilot electromagnetic valve 60 is connected to the second communication portion 56a. Consequently, a refrigerant pressure of the second pilot pipe 63a acts on the second chamber 56.
The high-pressure extraction portion 54a is provided in a space other than the first chamber 55 and the second chamber 56 of the internal space of the four-way switching valve body 50, the space being defined by the valve body 57 such that the fourth connection port 54 is positioned in the space. The high-pressure extraction pipe 64a, which is a capillary tube extending from the pilot electromagnetic valve 60, is connected to the high-pressure extraction portion 54a. Consequently, it is possible to lead the pressure of the high-pressure refrigerant that passes through the fourth connection port 54 to the pilot electromagnetic valve 60.
The low-pressure extraction portion 51a is provided at the first connection port 51. The low-pressure extraction pipe 61a, which is a capillary tube extending from the pilot electromagnetic valve 60, is connected to the low-pressure extraction portion 51a. Consequently, it is possible to lead the pressure of the low-pressure refrigerant that passes through the first connection port 51 to the pilot electromagnetic valve 60.
The pilot electromagnetic valve 60 includes four ports and the like, the four ports including a high-pressure extraction port 64, a low-pressure extraction port 61, a first action port 62, and a second action port 63.
The high-pressure extraction port 64 is connected to the high-pressure extraction portion 54a via the high-pressure extraction pipe 64a. The low-pressure extraction port 61 is connected to the low-pressure extraction portion 51a via the low-pressure extraction pipe 61a. The first action port 62 is connected to the first communication portion 55a via the first pilot pipe 62a. The second action port 63 is connected to the second communication portion 56a via the second pilot pipe 63a.
The controller 7 switches between the first connection state and the second connection state, the first connection state being a state in which, by causing an excitation coil, which is not illustrated, included in the pilot electromagnetic valve 60 to generate a magnetic field and moving a valve part against a force received from a spring and the like, a refrigerant pressure extracted by the low-pressure extraction port 61 is caused to act on the first action port 62 while a refrigerant pressure extracted by the high-pressure extraction port 64 is caused to act on the second action port 63, the second connection state being a state in which, by applying no voltage, a refrigerant pressure extracted by the low-pressure extraction port 61 is caused to act on the second action port 63 while a refrigerant pressure extracted by the high-pressure extraction port 64 is caused to act on the first action port 62.
The valve body 57 included in the four-way switching valve body 50 of the four-way switching valve 12 is preferably constituted by a resin other than nylon 66 and more preferably constituted by a resin containing at least one selected from the group consisting of PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PTFE (polytetrafluoroethylene), and PPS (polyphenylene sulfide), from the point of view of favorable lubricity, favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product thereof, and suppression of a decrease in the strength due to corrosion.
With regard to constituent components other than the valve body 57 of the four-way switching valve 12, for example, a protective film of a copper alloy or the like in which the percentage of zinc is 10 w % or less may be formed on a surface with which the refrigerant comes into contact.
(5) Structure of Outdoor Heat Exchanger 13 and Indoor Heat Exchanger 18
As illustrated in
From the point of view of favorable heat transfer properties and favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product thereof, such heat transfer tubes 41 can be constituted by a copper alloy in which the percentage of zinc is 10 wt % or less and is preferably constituted by a copper alloy in which the percentage of zinc is 5 wt % or less, and the heat transfer tubes 41 in which the percentage of copper is substantially 100% may be used.
From the point of view of favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product thereof, the liquid refrigerant connection pipe 6 and the gas refrigerant connection pipe 5 are also preferably constituted by a copper alloy in which the percentage of zinc is 10 wt % or less and is more preferably constituted by a copper alloy in which the percentage of zinc is 5 wt % or less, and the liquid refrigerant connection pipe 6 and the gas refrigerant connection pipe 5 in each of which the percentage of copper is substantially 100% may be used.
(6) Structure of Flare Connection Portion 8
The refrigerant circuit 10 is constituted by a plurality of refrigerant pipes that are connected to each other. As illustrated in
A case in which a first refrigerant pipe 81 and a second refrigerant pipe 82 that constitute part of the refrigerant circuit 10 are connected will be described here as an example.
An end portion of the first refrigerant pipe 81 includes a flare part 81a having a diameter that increases toward an end portion. The flare nut 83 is provided on the side of the first refrigerant pipe 81 including the flare part 81a.
An end portion of the second refrigerant pipe 82 is fixed to the joint body 84. The joint body 84 is a cylindrical member that has, at an outer peripheral portion, a screw groove in correspondence with a screw groove provided at the inner periphery of the flare nut 83. A part of the joint body 84 facing the flare part 81a has a shape in correspondence with the flare part 81a.
In the above configuration, the first refrigerant pipe 81 and the second refrigerant pipe 82 are coupled to each other by the flare nut 83 being screwed with respect to the joint body 84.
From the point of view of favorable suppression of corrosion due to the refrigerant containing CF3I or a decomposition product, the flare nut 83 described above can be a copper alloy in which the percentage of zinc is 10 wt % or less and is preferably a copper alloy in which the percentage of zinc is 5 wt % or less.
(7) Features of Embodiment
In an existing refrigerant circuit of a refrigerant cycle apparatus in which a refrigerant such as R410A or the like is used, for example, brass such as JIS C3604 or the like in which zinc is blended by approximately 30% is used as a balance weight of a compressor, and brass in which zinc is blended by approximately 30% is also used as a needle of an expansion valve. In the existing refrigerant circuit, a bearing including a bronze back metal on which an abrasion-resistant film of PTFE is formed is used as a bearing of the compressor, and nylon 66 is used as a valve body of a four-way switching valve.
However, the inventors confirmed that, when these components are exposed together with a refrigerant containing CF3I to an environment of approximately 175° C. for two weeks, corrosion occurs remarkably on the components, although no corrosion was confirmed on the components exposed together with R410A to the same condition. Specifically, corrosion progressed on brass to an extent that metallic luster was lost. A color change to brown was also confirmed on bronze. In addition, a color change to brown occurred on nylon 66, and nylon 66 changed to be brittle. Moreover, it was confirmed that it is not possible to sufficiently suppress corrosion on these components by only mixing a refrigerating-machine oil in the refrigerant containing CF3I and further inputting an additive agent, such as an acid scavenger. In contrast to this, when PET, PBT, and PTFE were exposed together with the refrigerant containing CF3I to an environment of approximately 175° C. for two weeks, corrosion found on nylon 66 was not confirmed.
Thus, as described above, a metal in which the percentage of zinc is suppressed to 10% or less is substituted, and a resin other than nylon 66 is substituted in the air conditioning apparatus 1 of the present embodiment. Consequently, it is possible, when the refrigerant containing CF3I is used as a working refrigerant, to suppress corrosion on a component due to the refrigerant containing CF3I.
Meanwhile, it was confirmed that aluminum or an aluminum alloy melts when exposed to a high temperature of approximately 175° C. under the presence of the refrigerant containing CF3I while it was also confirmed that melting was suppressed under a low temperature environment of 100° C. or less. Therefore, in the air conditioning apparatus 1 that is controlled, as described above, by the controller 7 such that the maximum temperature of a portion with which a fluid that flows in the refrigerant circuit 10 comes into contact is 100° C. or less, conditions required as a component is also taken into consideration, and aluminum or an aluminum alloy is usable.
(8) Modification
(8-1) Modification A
In the aforementioned embodiment, regarding members of the refrigerant circuit 10, a case in which the entirety of components are constituted by a corrosion resistance material has been described. In contrast to this, as long as satisfying conditions required for the components, the above-described corrosion resistance material may be provided as a protecting layer on these components by plating or the like, and parts of components other than the protecting layer may be constituted by a material other than a corrosion resistance material.
(9) Additional Remarks
The component may be constituted by a corrosion resistance material in the entirety thereof, or a part of the component to be in contact with the refrigerant may be coated with a protecting layer containing a corrosion resistance material while parts other than the protecting layer may be constituted by a material other than a corrosion resistance material.
The corrosion resistance material here is preferably a metal in which the percentage of zinc is 5 wt % or less and may be a copper alloy in which the percentage of zinc is 5 wt % or less. (10) Others Although an embodiment of the present disclosure have been described above, it should be understood that various changes in the forms and the details are possible without deviating from the spirit and the scope of the present disclosure described in the claims.
1 air conditioning apparatus (refrigerant cycle apparatus)
5 gas refrigerant connection pipe (refrigerant pipe, component)
6 liquid refrigerant connection pipe (refrigerant pipe, component)
7 control unit
9 expansion valve
10 refrigerant circuit
11 compressor
12 four-way switching valve
13 outdoor heat exchanger
18 indoor heat exchanger
26 lower bearing (bearing, component)
30 balance weight (component)
31 pin bearing (bearing, component)
35 upper bearing (bearing, component)
41 heat transfer tube (component)
57 valve body (component)
81 first refrigerant pipe (refrigerant pipe, component)
82 second refrigerant pipe (refrigerant pipe, component)
83 flare nut (component)
93 valve body (component)
93
b needle (component)
PTL 1: Japanese Unexamined Patent Application Publication No. 2017-149943
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-141322 | Jul 2019 | JP | national |
This application is a Continuation of PCT International Application No. PCT/JP2020/029112, filed on Jul. 29, 2020, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 2019-141322, filed in Japan on Jul. 31, 2019, all of which are hereby expressly incorporated by reference into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/029112 | Jul 2020 | US |
| Child | 17585776 | US |
