Accumulator, compressor, and refrigeration cycle device

Abstract

[Problem] To provide: an accumulator in which a gas-liquid separation capacity capable of reliably preventing outflow of a liquid refrigerant, in other words, a gas-liquid separation capacity capable of reliably preventing liquid compression by a compressor, and easy adjustment of a piping length of a suction piping system suitable for obtaining a supercharging effect of the compressor can both be achieved; a compressor provided with this accumulator; and a refrigeration cycle device. [Solution] This accumulator (7) comprises: a container (61); a partition plate (62) which is provided inside the container (61) and divides an internal space of the container (61) into a refrigerant introduction chamber IR and a refrigerant discharge chamber OR; an inlet pipe (63) which is fixed to the container (61) and has an inlet flow passage IP connected to the refrigerant introduction chamber IR; at least one communication pipe (65) having a communication flow passage CP connecting the refrigerant introduction chamber IR and the refrigerant discharge chamber OR; and at least one outlet pipe 1 (66) having an outlet flow passage OP connected to the refrigerant discharge chamber OR. The at least one communication pipe 65 has an outlet opening (65o) disposed in the refrigerant discharge chamber OR, and the at least one outlet pipe 66 has an inlet opening (66i) disposed in the refrigerant discharge chamber OR. The inlet opening (66i) of the at least one outlet pipe (66) can be disposed above the outlet opening (65o) of the at least one communication pipe (65), and the inlet opening (66i) of the at least one outlet pipe (66) and the outlet opening (65o) of the at least one communication pipe (65) can be installed so as not to overlap in the vertical direction.

Description

Accumulators, compressors, and refrigeration cycle devices

[0001] An embodiment according to the present invention relates to an accumulator, a compressor, and a refrigeration cycle device.

[0002] To prevent liquid refrigerant from being supplied into the cylinder of the compressor and compressed, i.e., to prevent liquid compression, an accumulator (gas-liquid separator, liquid separator) is known that is provided on the suction side of the compressor.

[0003] In order to ensure gas-liquid separation capability, a conventional accumulator includes a container, a partition plate that divides the internal space of the container into upper and lower sections, a straight pipe that extends vertically through the partition plate and opens into the bottom space, and an outlet pipe that opens into the bottom space and is led out from the underside of the container.

[0004] The lower end of the straight pipe, i.e., the outlet end of the straight pipe, is located near the partition plate, and the upper end of the outlet pipe, i.e., the inlet end of the outlet pipe, is located near the bottom plate of the container, i.e., the outlet end of the straight pipe is located above the inlet end of the outlet pipe.

[0005] Japanese Patent Application Publication No. 4-350479

[0006] In conventional accumulators, if liquid refrigerant flows into the bottom space of the container through the straight pipe, the liquid refrigerant can easily flow into the outlet pipe whose inlet end is near the bottom plate of the container, causing the compressor to enter liquid compression mode.

[0007] In designing a rotary compressor, the high load conditions under which the refrigerant circulation volume is large are extremely important in designing the theoretical suction volume, maximum rotation speed, and motor capacity. Utilizing the supercharging effect, which increases the refrigerant circulation volume at a specific rotation speed due to air column resonance in the compressor's suction piping system, is an effective design tool for rotary compressors.

[0008] Therefore, an object of the present invention is to provide an accumulator that can achieve both a gas-liquid separation ability that can reliably prevent the outflow of liquid refrigerant, in other words, a gas-liquid separation ability that can reliably prevent liquid compression in the compressor, and an accumulator that can easily adjust the piping length of the suction piping system suitable for obtaining a supercharging effect in the compressor, a compressor equipped with this accumulator, and a refrigeration cycle device.

[0009] In order to solve the above-mentioned problems, an accumulator according to an embodiment of the present invention comprises a container, a partition plate provided inside the container and dividing the internal space of the container into a refrigerant introduction chamber and a refrigerant discharge chamber, an inlet pipe fixed to the container and having an inlet flow path connected to the refrigerant introduction chamber, at least one connecting pipe passing through the partition plate and having a communication flow path connecting the refrigerant introduction chamber and the refrigerant discharge chamber, and at least one outlet pipe fixed to the container and having an outlet flow path connected to the refrigerant discharge chamber, wherein the at least one connecting pipe has an outlet opening disposed in the refrigerant discharge chamber and the at least one outlet pipe has an inlet opening disposed in the refrigerant discharge chamber, the inlet opening of the at least one outlet pipe is disposed above the outlet opening of the at least one connecting pipe, and the at least one outlet pipe can be installed so that the inlet opening of the at least one outlet pipe does not overlap the outlet opening of the at least one connecting pipe in the vertical direction.

[0010] In order to solve the above-mentioned problems, a compressor according to an embodiment of the present invention includes a sealed container, a compression mechanism housed in the sealed container, an electric motor housed in the sealed container and generating a driving force for the compression mechanism, and the accumulator disposed outside the sealed container and connected to the suction side of the compression mechanism.

[0011] Furthermore, in order to solve the above-mentioned problems, the refrigeration cycle device according to an embodiment of the present invention includes the compressor, a radiator, an expansion device, a heat absorber, and a refrigerant pipe that connects the compressor, the radiator, the expansion device, and the heat absorber and allows the refrigerant to circulate.

[0012] According to the present invention, it is possible to provide an accumulator that can achieve both a gas-liquid separation ability that can reliably prevent the outflow of liquid refrigerant, in other words, a gas-liquid separation ability that can reliably prevent liquid compression in the compressor, and an easy adjustment of the piping length of the suction piping system that is suitable for obtaining the supercharging effect of the compressor, as well as a compressor equipped with this accumulator and a refrigeration cycle device.

[0013] 1 is a schematic diagram of a refrigeration cycle device, a compressor, and an accumulator according to an embodiment of the present invention; 2 is a first longitudinal cross-sectional view of an accumulator according to an embodiment of the present invention; 3 is a second longitudinal cross-sectional view of an accumulator according to an embodiment of the present invention; 4 is a cross-sectional view of an accumulator according to an embodiment of the present invention; 5 is a diagram comparing the supercharging effect of the accumulator according to the present embodiment with that of a conventional accumulator; 6 is a diagram showing the relationship between the cross-sectional area of ​​a communication flow path and the cross-sectional area of ​​an outlet flow path of the accumulator according to the present embodiment;

[0014] An accumulator, a compressor, and a refrigeration cycle device according to an embodiment of the present invention will be described with reference to Figures 1 to 6. Note that the same or corresponding components are designated by the same reference numerals throughout the drawings.

[0015] FIG. 1 is a schematic diagram of a refrigeration cycle device, a compressor, and an accumulator according to an embodiment of the present invention.

[0016] As shown in Fig. 1, the refrigeration cycle apparatus 1 according to this embodiment includes a rotary compressor 2, a radiator 3, an expansion device 5, a heat absorber 6, an accumulator 7, and a refrigerant pipe 8. Hereinafter, the rotary compressor 2 will be simply referred to as the "compressor 2." The refrigerant pipe 8 sequentially connects the compressor 2, the radiator 3, the expansion device 5, the heat absorber 6, and the accumulator 7, allowing the refrigerant to circulate. The refrigerant circulating through the refrigeration cycle apparatus 1 may be any of a variety of refrigerants, such as carbon dioxide, R32, or a mixed refrigerant containing R32. The radiator 3 may also be called a condenser, and the heat absorber 6 may also be called an evaporator.

[0017] The compressor 2 comprises a cylindrical sealed container 11 that is placed vertically, an electric motor 12 housed in the upper half of the sealed container 11, a compression mechanism 13 housed in the lower half of the sealed container 11, a crankshaft 15 that transmits the rotational driving force of the electric motor 12 to the compression mechanism 13, and a main bearing 16 and an auxiliary bearing 17 that cooperate to support the crankshaft 15 so that it can rotate freely.

[0018] The sealed container 11 is cylindrical and includes a cylindrical body 11a extending in the vertical direction, a hemispherical or elliptical upper head 11b that closes the upper end of the body 11a, and a hemispherical or elliptical lower head 11c that closes the lower end of the body 11a.

[0019] The shell 11a supports a plurality of suction pipes 8b that guide the refrigerant to the compressor 2. The plurality of suction pipes 8b are connected to the accumulator 7. The plurality of suction pipes 8b are part of the refrigerant pipes 8.

[0020] The upper head plate 11b supports a discharge pipe 8a that discharges the refrigerant compressed by the compressor 2. The discharge pipe 8a is connected to the refrigerant pipe 8. The upper head plate 11b also includes a sealed terminal portion 18 that supplies power to the electric motor 12.

[0021] The electric motor 12 generates a driving force that rotates the compression mechanism 13. The electric motor 12 is, for example, a permanent magnet synchronous motor (PMSM). The electric motor 12 includes a cylindrical stator 21 fixed to the inner wall of the sealed container 11, a rotor 22 disposed inside the stator 21 and fixed to the crankshaft 15, and a plurality of lead wires 23 that are drawn from the stator 21 and connected to the sealed terminal portion 18.

[0022] The rotor 22 includes a rotor core having magnet accommodating holes and permanent magnets accommodated in the magnet accommodating holes. The rotor 22 is rotatable relative to the stator 21 and is fixed to the crankshaft 15 so as to rotate integrally with the stator 21. The rotational centerlines of the rotor 22 and the crankshaft 15 substantially coincide with the centerline of the stator 21.

[0023] The plurality of output wires 23 are wirings that supply power to the stator 21 through the sealed terminal portions 18, and are so-called lead wires. A plurality of output wires 23 are wired depending on the type of the electric motor 12. When the output wires 23 are used in an open winding type, two wires are wired for each of the U phase, V phase, and W phase, that is, a total of six output wires 23. When the electric motor 12 is used in a star connection, one wire is wired for each of the U phase, V phase, and W phase, that is, a total of three output wires 23.

[0024] The crankshaft 15 connects the electric motor 12 and the compression mechanism 13. The crankshaft 15 transmits the driving force generated by the electric motor 12 to the compression mechanism 13.

[0025] An intermediate portion 15a of the crankshaft 15 connects the electric motor 12 and the compression mechanism 13, and is rotatably supported by a main bearing 16. A lower end portion 15b of the crankshaft 15 is rotatably supported by an auxiliary bearing 17. The main bearing 16 and the auxiliary bearing 17 are also part of the compression mechanism 13. In other words, the crankshaft 15 passes through the compression mechanism 13.

[0026] The crankshaft 15 also has multiple eccentric portions 25a, 25b between a middle portion 15a supported by the main bearing 16 and a lower end portion 15b supported by the auxiliary bearing 17. Of the multiple eccentric portions 25, the one closer to the main bearing 16 is called a first eccentric portion 25a, and the one closer to the auxiliary bearing 17 is called a second eccentric portion 25b. Each of the eccentric portions 25a, 25b is a disk or cylinder whose center does not coincide with the center of the crankshaft 15. The centers of the eccentric portions 25a, 25b are eccentric around the crankshaft 15 with a phase difference of approximately 180 degrees. The first eccentric portion 25a is located on the upper side closer to the electric motor 12, and the second eccentric portion 25b is located on the lower side farther from the electric motor 12.

[0027] The upper main bearing 16 is fixed to the frame 14 via the first cylinder 32 by a plurality of fastening members, for example, bolts 55 and 56. The frame 14 is fixed to the sealed casing 11 at a plurality of locations by welding, for example, spot welding. In other words, the frame 14 supports the compression mechanism 13, the crankshaft 15, and the rotor 22 of the electric motor 12 on the sealed casing 11.

[0028] The compression mechanism 13 is driven to rotate by the electric motor 12 connected via the crankshaft 15, thereby drawing in gaseous refrigerant from the plurality of suction pipes 8b, compressing the drawn refrigerant, and discharging the compressed refrigerant into the sealed container 11. The lower part of the sealed container 11 is filled with refrigerating machine oil, and most of the compression mechanism 13 is immersed in this refrigerating machine oil.

[0029] The compression mechanism 13 includes a plurality of, for example, two, cylinders 26 and 27. In other words, the compressor 2 is a multi-cylinder rotary compressor. The compression mechanism 13 includes a first cylinder 26 provided in the sealed container 11, a second cylinder 27 provided in the sealed container 11, and a partition plate 29 provided between the first cylinder 26 and the second cylinder 27.

[0030] The compressor 2 may be a multi-cylinder rotary compressor having three or more cylinders, or may be a single-cylinder rotary compressor. The compressor 2 and the accumulator 7 are connected via suction pipes 8b, the number of which is the same as the number of cylinders.

[0031] The first cylinder 26 includes a first cylinder 32 having a circular first cylinder chamber 31, and an annular first rolling piston 33 disposed in the first cylinder chamber 31. Hereinafter, the first rolling piston 33 will be simply referred to as the "first piston 33."

[0032] The second cylinder 27 includes a second cylinder 42 having a circular second cylinder chamber 41, and an annular second rolling piston 43 disposed within the second cylinder chamber 41. Hereinafter, the second rolling piston 43 will be simply referred to as the "second piston 43."

[0033] Each cylinder 26, 27 is provided with a vane 45 that reciprocates toward and away from the rotational centerline of the crankshaft 15 while remaining in contact with the outer circumferential surface of the corresponding piston 33, 43, dividing the corresponding cylinder chamber 31, 41 into a suction chamber and a compression chamber. The volume of the compression chamber defined by the corresponding piston 33, 43 and the corresponding vane 45 in each cylinder 26, 27 is changed by the rotation of the piston 33, 43, thereby compressing the refrigerant. Only the second cylinder 27 is shown with a vane 45.

[0034] The first cylinder 32 and the second cylinder 42 are arranged so as to be stacked in the axial direction of the crankshaft 15. The upper first cylinder 32 is arranged on the side closer to the electric motor 12. The lower second cylinder 42 is arranged on the side farther from the electric motor 12.

[0035] Each of the cylinders 32, 42 has an inner circumferential surface that defines the corresponding cylinder chamber 31, 41. Each of the cylinders 32, 42 has an annular, plate-like shape with the corresponding cylinder chamber 31, 41 inside. Each of the cylinders 32, 42 has an end face that is closer to the electric motor 12 and an end face that is farther from the electric motor 12.

[0036] The centers of the first cylinder chamber 31 and the second cylinder chamber 41 substantially coincide with the rotational centerline of the crankshaft 15. These cylinder chambers 31, 41 have substantially the same diameter and height, i.e., the dimensions in the longitudinal direction of the crankshaft 15. The first cylinder chamber 31 is the space inside the first cylinder 32 and is closed by the main bearing 16 and the partition plate 29. The first cylinder chamber 31 houses the first eccentric portion 25a of the crankshaft 15. The second cylinder chamber 41 is the space inside the second cylinder 42 and is closed by the partition plate 29 and the sub-bearing 17. The second cylinder chamber 41 houses the second eccentric portion 25b of the crankshaft 15.

[0037] The compression mechanism 13 includes a first discharge valve mechanism having a discharge port provided in the main bearing 16 for discharging the refrigerant compressed in the first cylinder chamber 31 to the outside of the first cylinder chamber 31, and a discharge valve provided in the main bearing 16 for opening and closing the discharge port, and a first discharge muffler 55 provided in the main bearing 16 for covering the first discharge valve mechanism.

[0038] The discharge port of the first discharge valve mechanism is connected to the first cylinder chamber 31 .

[0039] The discharge valve of the first discharge valve mechanism opens the discharge port when the differential pressure between the inside and outside of the first cylinder chamber 31 reaches a predetermined differential pressure value due to the compression action of the compression mechanism 13, and discharges the compressed refrigerant into the first discharge muffler 55.

[0040] The first discharge muffler 55 covers the first discharge valve mechanism. The first discharge muffler 55 has a discharge hole penetrating the first discharge muffler 55. The compressed refrigerant discharged into the first discharge muffler 55 is discharged into the sealed container 11 through the discharge hole.

[0041] The first discharge muffler 55 and the first cylinder 32 are fixed to the main bearing 16 by a plurality of fastening members, for example, bolts 56. The bolts 56 pass through the first discharge muffler 55 and the main bearing 16 and reach the first cylinder 32.

[0042] The compression mechanism 13 also includes a second discharge valve mechanism having a discharge port provided in the auxiliary bearing 17 and discharging the refrigerant compressed in the second cylinder chamber 41, and a discharge valve provided in the auxiliary bearing 17 and opening and closing the discharge port, and a second discharge muffler 57 provided in the auxiliary bearing 17 and covering the second discharge valve mechanism.

[0043] The discharge port of the second discharge valve mechanism is connected to the second cylinder chamber 41 .

[0044] The discharge valve of the second discharge valve mechanism opens the discharge port when the differential pressure between the inside and outside of the second cylinder chamber 41 reaches a predetermined differential pressure value due to the compression action of the compression mechanism 13, and discharges the compressed refrigerant into the second discharge muffler 57.

[0045] The second discharge valve mechanism is covered by the second discharge muffler 57. The compressed refrigerant discharged into the second discharge muffler 57 is guided to the first discharge muffler 55 through a hole that penetrates the auxiliary bearing 17, the second cylinder 42, the partition plate 29, and the first cylinder 32, and is then discharged into the sealed container 11.

[0046] The second discharge muffler 57, the auxiliary bearing 17, the second cylinder 42, and the partition plate 29 are fixed to the first cylinder 32 by a plurality of fastening members, for example, bolts 58. The bolts 58 pass through the second discharge muffler 57, the auxiliary bearing 17, the second cylinder 42, and the partition plate 29 and reach the first cylinder 32.

[0047] The first piston 33 is fitted onto the circumferential surface of the first eccentric portion 25a and is housed in the first cylinder chamber 31. As the crankshaft 15 rotates, the first piston 33 moves eccentrically while a portion of its outer circumferential surface is in line contact with the inner circumferential surface of the first cylinder chamber 31.

[0048] The second piston 43 is fitted onto the circumferential surface of the second eccentric portion 25b and is housed in the second cylinder chamber 41. As the crankshaft 15 rotates, the second piston 43 moves eccentrically while a portion of its outer circumferential surface is in line contact with the inner circumferential surface of the second cylinder chamber 41.

[0049] Note that the contact between the first piston 33 and the first cylinder 32 and the contact between the second piston 43 and the second cylinder 42 is not direct contact but indirect contact via an oil film (not shown), but for ease of explanation, this contact via an oil film will be simply referred to as "contact." The same applies to the contact between the first piston 33 and the first eccentric portion 25a, between the second piston 43 and the second eccentric portion 25b, between the first piston 33 and the main bearing 16, between the second piston 43 and the sub-bearing 17, between the first piston 33 and the partition plate 29, and between the second piston 43 and the partition plate 29.

[0050] The accumulator 7 is fixed to the sealed container 11 of the compressor 2 by a clamp band 59 .

[0051] 2 and 3 are vertical cross-sectional views of an accumulator according to an embodiment of the present invention.

[0052] As shown in Figures 2 and 3 in addition to Figure 1, the accumulator 7 of this embodiment includes a cylindrical container 61 supported in an upright position, a partition plate 62 provided inside the container 61 and dividing the internal space S of the container 61 into a refrigerant introduction chamber IR and a refrigerant discharge chamber OR, an inlet pipe 63 fixed to the container 61 and having an inlet flow path IP connected to the refrigerant introduction chamber IR, at least one communication pipe 65 passing through the partition plate 62 and having a communication flow path CP connecting the refrigerant introduction chamber IR and the refrigerant discharge chamber OR, and a plurality of outlet pipes 66 fixed to the container 61 and having an outlet flow path OP connected to the refrigerant discharge chamber OR.

[0053] The accumulator 7 also includes a strainer 71 that is disposed between the inlet pipe 63 and the connecting pipe 65 and filters out foreign matter from the refrigerant introduced into the accumulator 7, a separation plate 72 that is disposed between the strainer 71 and the connecting pipe 65 and separates the refrigerant that has passed through the strainer 71 into gas refrigerant and liquid refrigerant, and a support plate 73 that is disposed between the separation plate 72 and the partition plate 62 and supports the connecting pipe 65 together with the partition plate 62.

[0054] It is sufficient to have at least one communication pipe 65. For ease of explanation, the accumulator 7 of this embodiment is assumed to have a plurality of, for example, two, communication pipes 65. The number of communication pipes 65 is determined in consideration of the pressure loss in the communication flow path CP that connects the refrigerant introduction chamber IR and the refrigerant discharge chamber OR.

[0055] The container 61 is fixed to the sealed container 11 of the compressor 2 by a clamp band 59. The container 61 is cylindrical and includes a cylindrical body 61a extending in the vertical direction, a hemispherical or elliptical upper head 61b that closes the upper end, which is one end of the body 61a, and a hemispherical or elliptical lower head 61c that closes the lower end, which is the other end of the body 61a.

[0056] The body 61a supports, in the order of the refrigerant flow, a strainer 71, a separation plate 72, a support plate 73, and a partition plate 62.

[0057] The upper head plate 61b supports an inlet pipe 63 through which the refrigerant compressed by the compressor 2 and circulated through the refrigeration cycle device 1 flows into the accumulator 7. The inlet pipe 63 is connected to a refrigerant pipe 8.

[0058] The inlet pipe 63 is fixed to the upper head plate 61b and connected to the refrigerant pipe 8. The inlet pipe 63 is a straight pipe that extends along the center line of the body 61a, and is a straight pipe that extends in line with the center line of the body 61a.

[0059] The refrigerant flowing into the accumulator 7 from the inlet pipe 63 first reaches the strainer 71. The strainer 71 has a required mesh size so as to prevent foreign matter from flowing into the compression mechanism 13 of the compressor 2.

[0060] The separator plate 72 prevents the refrigerant that has passed through the strainer 71 from flowing directly into the connecting pipe 65. The separator plate 72 is a plate with an upwardly convex shape that acts like an umbrella on the connecting pipe 65. The separator plate 72 has a plurality of openings 72a through which the refrigerant can pass. The separator plate 72 blocks the view directly below the inlet pipe 63 and blocks the view directly above the connecting pipe 65. The plurality of openings 72a of the separator plate 72 are arranged outside the smallest imaginary circle that encompasses the plurality of connecting pipes 65 when viewed from the inlet pipe 63. The refrigerant that reaches the separator plate 72 flows down into the refrigerant introduction chamber IR of the container 61 through the plurality of openings 72a of the separator plate 72.

[0061] The support plate 73 and the partition plate 62 cooperate to support at least one connecting pipe 65 inside the container 61 .

[0062] The support plate 73 has holes that support the connecting pipe 65 so that the refrigerant introduction chamber IR is a continuous space, and appropriate openings that do not obstruct the flow of liquid refrigerant and gas refrigerant. The support plate 73 preferably has appropriate support strength and support rigidity so that the connecting pipe 65 extending from the partition plate 62 toward the separation plate 72 does not tip over.

[0063] The partition plate 62 has no openings other than the hole that supports the connecting pipe 65, so that the internal space S of the container 61 is divided into a refrigerant introduction chamber IR and a refrigerant discharge chamber OR. The partition plate 62 is liquid-tightly and airtightly joined to the inner surface of the container 61, and prevents the refrigerant from flowing from the refrigerant introduction chamber IR to the refrigerant discharge chamber OR through any path other than the connecting pipe 65. The partition plate 62 only needs to have a plane that is perpendicular to the center line of the container 61, and defines a plane that extends horizontally when the accumulator 7 is in an upright position.

[0064] Each of the communication pipes 65 has an inlet opening 65i disposed in the refrigerant introduction chamber IR and an outlet opening 65o disposed in the refrigerant discharge chamber OR. The inlet opening 65i corresponds to the upstream end of the communication flow path CP, and the outlet opening 65o corresponds to the downstream end of the communication flow path CP.

[0065] Each of the communication pipes 65 is disposed inside the container 61, and is fixed to the support plate 73 and the partition plate 62 to connect the refrigerant introduction chamber IR and the refrigerant discharge chamber OR. Each of the communication pipes 65 is a straight pipe that extends along the center line of the body 61a and is a straight pipe that extends parallel to the center line of the body 61a.

[0066] The length of each of the communication pipes 65 depends on the amount of refrigerant charged in the refrigeration cycle device 1, but is preferably approximately equal to or greater than half the total length of the accumulator 7.

[0067] Each outlet pipe 66 is the suction pipe 8b of the compressor 2, and is connected to the cylinder chambers 31, 41 of the corresponding cylinders 26, 27 of the compression mechanism 13. The number of outlet pipes 66 is the same as the number of cylinders of the compressor 2. In the case of a multi-cylinder compressor 2 as shown in FIG. 1 , the accumulator 7 is connected to the compressor 2 by the same number of outlet pipes 66 as the number of cylinders. In the case of a single-cylinder compressor 2, it is sufficient for the accumulator 7 to be connected to the compressor 2 by one outlet pipe 66. In other words, it is sufficient for the accumulator 7 to have at least one outlet pipe 66, and it is preferable for the accumulator 7 to have the same number of outlet pipes 66 as the number of cylinders of the compressor 2.

[0068] Each outlet pipe 66 allows gas refrigerant separated from the refrigerant that has flowed into the accumulator 7 to flow out from the accumulator 7. Each outlet pipe 66 is fixed to the lower head 61c and connected to the compressor 2. The inner portion of the outlet pipe 66 in the container 61 is a straight pipe that extends along the center line of the body 61a and is a straight pipe that extends parallel to the center line of the body 61a.

[0069] Each outlet pipe 66 has an inlet opening 66i disposed in the refrigerant discharge chamber OR and an outlet opening 66o connected to the corresponding cylinder chamber 31, 41. The inlet opening 66i corresponds to the upstream end of the outlet flow path OP, and the outlet opening 66o corresponds to the downstream end of the outlet flow path OP.

[0070] The multiple outlet pipes 66 overlap the multiple connecting pipes 65 when viewed in the radial direction of the container 61. In other words, the inlet openings 66i of the multiple outlet pipes 66 are positioned higher than the outlet openings 65o of the multiple connecting pipes 65. The inlet openings 66i of the multiple outlet pipes 66 are closer to the partition plate 62 than the outlet openings 65o of the multiple connecting pipes 65. The outlet openings 65o of the multiple connecting pipes 65 are closer to the lower head plate 61c than the inlet openings 66i of the multiple outlet pipes 66. In other words, the accumulator 7 is configured so that it can be installed in the compressor 2 with the inlet openings 66i of the multiple outlet pipes 66 positioned higher than the outlet openings 65o of the multiple connecting pipes 65.

[0071] The inlet openings 66i of the outlet pipes 66 face the partition plate 62 upward, and the outlet openings 65o of the connecting pipes 65 face the lower end plate 61c downward.

[0072] The inlet openings 65i of the plurality of connecting pipes 65 are closer to the upper head plate 61b than to the partition plate 62, and the inlet openings 66i of the plurality of outlet pipes 66 are closer to the partition plate 62 than to the lower head plate 61c.

[0073] The inlet openings 65i of the respective connecting pipes 65 are disposed at substantially the same height. In other words, the accumulator 7 is configured so that the inlet openings 65i of the plurality of connecting pipes 65 can be disposed at substantially the same height.

[0074] The vessel 61 is an assembly of three members that are divided and hermetically joined midway along the body 61a on the upper head plate 61b side and midway along the body 61a on the lower head plate 61c side. The inlet pipe 63, strainer 71, and separation plate 72 are preferably assembled into the upper member before assembling the vessel 61, the outlet pipe 66 is assembled into the lower member before assembling the vessel 61, and the partition plate 62, support plate 73, and connecting pipe 65 are preferably assembled into the central member before assembling the vessel 61. The support plate 73 may be disposed at the dividing surface between the upper and central members, or may be fixed to the inside of the central member.

[0075] The container 61 may be an assembly of two members that are split midway through the body 61a and hermetically joined. It is preferable that the inlet pipe 63, strainer 71, and separation plate 72 are assembled into the upper member before assembling the container 61, and the outlet pipe 66, partition plate 62, support plate 73, and connecting pipe 65 are assembled into the lower member before assembling the container 61. The support plate 73 may be disposed at the dividing surface of the two members, or may be fixed to the inside of the lower member.

[0076] FIG. 4 is a cross-sectional view of an accumulator according to an embodiment of the present invention.

[0077] FIG. 4 is a cross section that allows the positional relationship between the container 61 of the accumulator 7, the plurality of connecting pipes 65, and the plurality of outlet pipes 66 to be understood, for example, a cross section taken along line IV-IV in FIGS.

[0078] 4, the inlet openings 66i of the multiple outlet pipes 66 of the accumulator 7 according to this embodiment are arranged so as not to overlap in the vertical direction with the outlet openings 65o of the multiple connecting pipes 65. In other words, the accumulator 7 is configured so that the inlet openings 66i of the multiple outlet pipes 66 can be installed so as not to overlap in the vertical direction with the outlet openings 65o of the multiple connecting pipes 65.

[0079] The accumulator 7 according to this embodiment includes two outlet pipes 66 corresponding to the two-cylinder compressor 2 and two communication pipes 65 connecting the refrigerant introduction chamber IR and the refrigerant discharge chamber OR. The two outlet pipes 66 and the two communication pipes 65 are arranged alternately in the circumferential direction of the container 61. This arrangement allows the communication pipes 65 and the outlet pipes 66 to overlap each other when viewed in the radial direction of the container 61. This arrangement of the communication pipes 65 and the outlet pipes 66 prevents the liquid refrigerant flowing from the communication passage CP to the refrigerant discharge chamber OR from flowing directly from the inlet opening 66i of the outlet pipe 66 to the outlet passage OP, even if the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet opening 65i of any of the communication pipes 65 and the liquid refrigerant flows down the communication passage CP of any of the communication pipes 65.

[0080] In the accumulator 7 configured as described above, the refrigerant flowing down from the inlet pipe 63 into the refrigerant introduction chamber IR in the container 61 hits the separation plate 72 and is separated into gas refrigerant and liquid refrigerant. The separated liquid refrigerant flows further down within the refrigerant introduction chamber IR from the opening 72a of the separation plate 72 and accumulates at the bottom of the refrigerant introduction chamber IR, i.e., on the partition plate 62 side. Meanwhile, the separated gas refrigerant flows from the opening 72a of the separation plate 72 through the multiple connection pipes 65 into the refrigerant discharge chamber OR. The gas refrigerant that has flowed into the refrigerant discharge chamber OR is sucked into the outlet pipe 66 and sent to the compressor 2.

[0081] The accumulator 7 does not allow the liquid refrigerant accumulated in the refrigerant introduction chamber IR to flow into the refrigerant discharge chamber OR unless the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet openings 65i of the plurality of communication pipes 65. Furthermore, if the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet openings 65i of the plurality of communication pipes 65, the liquid refrigerant flows down the communication pipes 65 and accumulates at the bottom of the container 61, i.e., on the lower end plate 61c side. Again, the accumulator 7 does not allow the liquid refrigerant accumulated in the refrigerant discharge chamber OR to flow into the outlet pipes 66 unless the liquid level of the liquid refrigerant accumulated in the refrigerant discharge chamber OR reaches the inlet openings 66i of the plurality of outlet pipes 66. In this way, the accumulator 7 can prevent liquid compression of the compressor 2 in multiple ways.

[0082] FIG. 5 is a diagram comparing the supercharging effect of the accumulator according to this embodiment with that of a conventional accumulator.

[0083] In FIG. 5, the horizontal axis represents the operating frequency (Hertz, Hz, 1 / second) of the crankshaft 15 of the compressor 2, and the vertical axis represents normalized values ​​obtained by dividing the volumetric efficiency at each operating frequency by the maximum volumetric efficiency when the operating frequency of the compressor 2 is changed from 30 Hz to 120 Hz.

[0084] 5 does not have the connecting pipe 65 and partition plate 62 of the accumulator 7 according to this embodiment, but instead has an outlet pipe 66 that protrudes from the lower head 61c into the internal space S of the container 61 and extends to the vicinity of the separation plate 72, and has an inlet opening 66o facing the separation plate 72, and a support plate 73 that supports the outlet pipe 66. In this conventional accumulator 7, the length of the straight pipe portion of the outlet pipe 66 inside the container 61 is 0.35 times the length of the straight pipe portion of the outlet pipe 66 according to this embodiment inside the container 61.

[0085] When connected to the exact same compressor 2, the volumetric efficiency of the conventional accumulator indicated by the dashed line α reaches its maximum value at an operating frequency of 85 Hz, while the volumetric efficiency of the accumulator 7 according to this embodiment indicated by the solid line β reaches its maximum value at an operating frequency of 110 Hz. In other words, the accumulator 7 according to this embodiment exhibits a supercharging effect at a higher frequency than the conventional accumulator 7. The accumulator 7 allows the piping length of the suction piping system of the compressor 2, including the outlet pipe 66 and the connecting pipe 65, to be easily adjusted to the piping length required for the supercharging effect, allowing for extremely high design freedom in accordance with the characteristics of the compressor 2.

[0086] Here, the relationship between the sum of the cross-sectional areas of the inlet flow passages IP, ΣAip, the sum of the cross-sectional areas of the communication flow passages CP, and the sum of the cross-sectional areas of the outlet flow passages OP, ΣAop, will be described.

[0087] The sum of the cross-sectional areas ΣAip of the inlet flow passages IP is substantially equal to the cross-sectional area Aip of one inlet pipe 63.

[0088] The sum of the cross-sectional areas ΣAcp of the communication flow passages CP is the sum of the cross-sectional areas Acp of each communication pipe 65. The cross-sectional areas Acp of the multiple communication pipes 65 may be the same or different. In other words, the multiple communication pipes 65 may be multiple pipes having the same inner diameter, or multiple pipes having different inner diameters. If the target sum of the cross-sectional areas ΣAcp can be obtained by combining pipes with the same inner diameter, the multiple communication pipes 65 only need to have the same inner diameter. If the target sum of the cross-sectional areas ΣAcp can be obtained by combining pipes with different inner diameters, the multiple communication pipes 65 may have different inner diameters.

[0089] The sum ΣAop of the cross-sectional areas of the outlet flow paths OP is the sum of the cross-sectional areas Aop of each outlet pipe 66. The cross-sectional areas Aop of the multiple outlet pipes 66 may be the same or different. In other words, the multiple outlet pipes 66 may be multiple pipes having the same inner diameter or multiple pipes having different inner diameters. The cross-sectional area Aop of each outlet pipe 66 depends on the effective volume of the corresponding cylinder 26, 27.

[0090] The sum ΣAip of the cross-sectional areas of the inlet flow paths IP is preferably larger than the sum ΣAop of the cross-sectional areas of the outlet flow paths OP. This relationship in size between the cross-sectional areas of the flow paths promotes stagnation and retention of the liquid refrigerant in the accumulator 7 and promotes separation of the liquid refrigerant and the gas refrigerant.

[0091] Furthermore, the sum of the cross-sectional areas of the communication channels CP, ΣAcp, is preferably equal to or greater than the sum of the cross-sectional areas of the inlet channels IP. This relationship in the cross-sectional areas of the channels contributes to the rapid flow of the gas refrigerant separated in the refrigerant introduction chamber IR into the refrigerant discharge chamber OR.

[0092] FIG. 6 is a diagram showing the relationship between the cross-sectional area of ​​the communication flow path and the cross-sectional area of ​​the outlet flow path of the accumulator according to this embodiment.

[0093] In FIG. 6, the horizontal axis represents the area ratio AR obtained by dividing the sum of the cross-sectional areas of the communication passages CP, ΣAcp, by the sum of the cross-sectional areas of the outlet passages OP, ΣAop, and the vertical axis represents the volumetric efficiency of the compressor 2 at the same operating frequency.

[0094] (Area ratio AR)=(total cross-sectional area of ​​communication flow passages CP ΣAcp) / (total cross-sectional area of ​​outlet flow passages OP ΣAop).

[0095] 6, when the area ratio AR is smaller than 1.2, the volumetric efficiency of the compressor 2 increases rapidly, and when the area ratio AR is 1.2 or greater, the volumetric efficiency of the compressor 2 converges after having increased sufficiently. Therefore, it is preferable that the sum ΣAcp of the cross-sectional areas of the communication flow paths CP is 1.2 times or more the sum ΣAop of the cross-sectional areas of the outlet flow paths OP.

[0096] Therefore, it is preferable that the sum ΣAcp of the cross-sectional areas Acp of the multiple communication channels CP is equal to or larger than the sum ΣAip of the cross-sectional areas Aip of the inlet channels IP and is 1.2 times or larger than the sum ΣAop of the cross-sectional areas Aop of the multiple outlet channels OP. It is preferable that the relationship in size between the cross-sectional areas holds even when the inlet pipe 63, the communication pipe 65, and the outlet pipe 66 are all one pipe.

[0097] 6, the volumetric efficiency of the compressor 2 decreases when the area ratio AR exceeds a predetermined value. Specifically, when the area ratio AR exceeds 1.30, the volumetric efficiency of the compressor 2 tends to decrease, and when the area ratio AR exceeds 1.6, the volumetric efficiency of the compressor 2 falls below the volumetric efficiency of the compressor 2 at an area ratio of 1.2.

[0098] Furthermore, if the area ratio AR is too large, i.e., if the communication passage CP is too large, the proportion of the internal space S of the accumulator 7 that is occupied by the communication passage CP increases, reducing the liquid refrigerant storage capacity of the refrigerant inlet chamber IR and the refrigerant discharge chamber OR. Therefore, it is more preferable that the area ratio AR is 1.6 or less.

[0099] Generally, the capacity and inner diameter of the accumulator 7 attached to the compressor 2 are changed as appropriate depending on the operating capacity of the compressor 2. For example, the inner diameter of the accumulator 7 is generally three to six times the outer diameter of the outlet pipe 66. The inner diameter of the accumulator 7 according to this embodiment is approximately five times the outer diameter of the outlet pipe 66. The inlet opening 65i of the connecting pipe 65 is arranged so as not to face the multiple openings provided in the separation plate 72. The refrigerant flowing through the multiple openings of the separation plate 71 is prevented from being directly supplied to the inlet opening 65i of the connecting pipe 65.

[0100] The sum of the cross-sectional areas of the communication flow paths CP, ΣAcp, can be maximized within the refrigerant discharge chamber OR when the lower ends of the plurality of communication pipes 65 and the upper ends of the plurality of outlet pipes 66 overlap vertically and the inlet openings 65i of the plurality of communication pipes 65 are positioned outside the smallest imaginary circle that encompasses the plurality of communication pipes 65 as viewed from the inlet pipe 63. When the communication pipes 65 and the outlet pipes 66 are positioned in this manner, setting the area ratio AR to 1.6 or less makes it possible to maintain a high volumetric efficiency of the compressor 2, without reducing the amount of liquid refrigerant stored in the refrigerant introduction chamber IR, and to prevent the accumulator 7 from becoming large.

[0101] As described above, the accumulator 7 according to this embodiment can be installed such that the inlet opening 66i of at least one outlet pipe 66 is disposed above the outlet opening 65o of at least one connecting pipe 65 and does not overlap the outlet opening 65o of at least one connecting pipe 65 in the vertical direction. The compressor 2 and refrigeration cycle apparatus 1 according to this embodiment include the accumulator 7, in which the inlet opening 66i of at least one outlet pipe 66 is disposed above the outlet opening 65o of at least one connecting pipe 65 and does not overlap the outlet opening 65o of at least one connecting pipe 65 in the vertical direction. Therefore, the accumulator 7, the compressor 2, and the refrigeration cycle apparatus 1 can accumulate liquid refrigerant in multiple stages in the refrigerant introduction chamber IR and the refrigerant discharge chamber OR within the accumulator 7, even if liquid refrigerant returns to the accumulator 7. In this way, the accumulator 7, the compressor 2, and the refrigeration cycle apparatus 1 can prevent the liquid refrigerant from easily flowing out from at least one outlet pipe 66, and can therefore prevent liquid compression in the compressor 2. Furthermore, the accumulator 7, the compressor 2, and the refrigeration cycle apparatus 1 can easily achieve both prevention of liquid compression in the compressor 2 and utilization of the supercharging effect by adjusting the piping length of the suction piping system of the compressor 2, including the outlet pipe 66 and the connecting pipe 65, as shown in Fig. 5 .

[0102] Furthermore, the accumulator 7, compressor 2, and refrigeration cycle apparatus 1 according to this embodiment have an inlet opening 66i of the outlet pipe 66 facing upward through the partition plate 62, and an outlet opening 65o of the connecting pipe 65 facing downward through the lower end plate 61c. The inner portion of the outlet pipe 66 inside the container 61, the inlet pipe 63, and the connecting pipe 65 are straight pipes extending parallel to the center line of the body 61a of the container 61. Therefore, the vertically-mounted accumulator 7, the vertically-mounted compressor 2, and the refrigeration cycle apparatus 1 including them can easily prevent liquid compression in the compressor 2 while utilizing the supercharging effect.

[0103] Furthermore, the accumulator 7, compressor 2, and refrigeration cycle apparatus 1 according to this embodiment have an inlet opening 66i of the outlet pipe 66 that is closer to the partition plate 62 than the lower head 61c. Therefore, the accumulator 7, compressor 2, and refrigeration cycle apparatus 1 ensure the amount of liquid refrigerant stored in the refrigerant discharge chamber OR. Maximizing the amount of liquid refrigerant stored in the refrigerant discharge chamber OR prevents the liquid refrigerant that has flowed from the connection pipe 65 into the refrigerant discharge chamber OR from immediately flowing out into the compressor 2, even if the liquid refrigerant overflows from the refrigerant introduction chamber IR into the connection pipe 65.

[0104] The accumulator 7 according to this embodiment includes a plurality of communication pipes 65 whose inlet openings 65i can be arranged at substantially the same height. The compressor 2 and the refrigeration cycle apparatus 1 according to this embodiment include a plurality of communication pipes 65 whose inlet openings 65i are arranged at substantially the same height. Therefore, the accumulator 7, the compressor 2, and the refrigeration cycle apparatus 1 can easily set the positional relationship between the communication pipe 65 and the outlet pipe 66 so that the outlet opening 65o of the communication pipe 65 and the inlet opening 66i of the outlet pipe 66 do not overlap in the vertical direction in which the liquid refrigerant flows down, while ensuring the flow path cross-sectional area of ​​the communication flow path CP. In other words, even if the liquid level of the liquid refrigerant accumulated in the refrigerant introduction chamber IR reaches the inlet opening 65i of any of the communication pipes 65 and the liquid refrigerant flows down the communication flow path CP of any of the communication pipes 65, the accumulator 7, the compressor 2, and the refrigeration cycle device 1 prevent the liquid refrigerant flowing from the communication flow path CP to the refrigerant discharge chamber OR from flowing directly into the outlet flow path OP from the inlet opening 66i of the outlet pipe 66. Furthermore, by individually setting the communication flow paths CP of the multiple communication pipes 65 to be different or the same, the total pressure loss of the multiple communication flow paths CP can be easily adjusted.

[0105] Furthermore, the accumulator 7, the compressor 2, and the refrigeration cycle device 1 according to this embodiment are provided with a plurality of outlet pipes 66. Therefore, the accumulator 7, the compressor 2, and the refrigeration cycle device 1 can easily accommodate a multi-cylinder compressor 2.

[0106] Furthermore, the accumulator 7, compressor 2, and refrigeration cycle apparatus 1 according to this embodiment include at least one communication pipe 65 in which the sum ΣAcp of the cross-sectional areas Acp is equal to or greater than the sum ΣAip of the cross-sectional areas Aip of the inlet flow passages IP and is 1.2 times or greater than the sum ΣAop of the cross-sectional areas Aop of the multiple outlet flow passages OP. Therefore, the accumulator 7, compressor 2, and refrigeration cycle apparatus 1 improve the gas-liquid separation performance of the accumulator 7 and promote utilization of the supercharging effect without impeding the flow of refrigerant in the accumulator 7 due to pressure loss in the at least one communication pipe 65 connecting the refrigerant introduction chamber IR and the refrigerant discharge chamber OR.

[0107] Furthermore, the accumulator 7 and the refrigeration cycle apparatus 1 according to this embodiment include an inlet pipe 63 in which the sum ΣAip of the cross-sectional areas Aip is larger than the sum ΣAop of the cross-sectional areas Aop of the outlet flow paths OP. Therefore, the accumulator 7, the compressor 2, and the refrigeration cycle apparatus 1 promote stagnation and retention of the liquid refrigerant in the accumulator 7, and promote separation of the liquid refrigerant and the gas refrigerant.

[0108] Therefore, the accumulator 7, compressor 2, and refrigeration cycle device 1 according to this embodiment can achieve both a gas-liquid separation ability that can reliably prevent the outflow of liquid refrigerant, in other words, a gas-liquid separation ability that can reliably prevent liquid compression in the compressor 2, and easy adjustment of the piping length of the suction piping system that is suitable for obtaining the supercharging effect of the compressor 2.

[0109] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0110] DESCRIPTION OF SYMBOLS 1... Refrigeration cycle device, 2... rotary compressor, 3... radiator, 5... expansion device, 6... heat absorber, 7... accumulator, 8... refrigerant pipe, 8b... suction pipe, 8a... discharge pipe, 11... sealed container, 11a... shell, 11b... upper head plate, 11c... lower head plate, 12... electric motor, 13... compression mechanism, 14... frame, 15... crankshaft, 15a... middle portion, 15b... lower end portion, 16... main bearing, 17... auxiliary bearing, 18... sealed terminal portion, 21... stator, 22... rotor, 23... lead wire, 25... eccentric portion, 25a... first eccentric portion, 25b... second eccentric portion, 26... first cylinder, 27... second cylinder, 29... partition plate, 31 ...First cylinder chamber, 32...First cylinder, 33...First rolling piston, 41...Second cylinder chamber, 42...Second cylinder, 43...Second rolling piston, 45...Vane, 55...First discharge muffler, 55, 56...Bolt, 57...Second discharge muffler, 58...Bolt, 59...Clamp band, 61...Container, 61a...Body, 61b...Upper head plate, 61c...Lower head plate, 62...Partition plate, 63...Inlet pipe, 65...Connecting pipe, 65i...Inlet opening, 65o...Outlet opening, 66...Outlet pipe, 66i...Inlet opening, 66o...Outlet opening, 71...Strainer, 72...Separator plate, 73...Support plate.

Claims

1. Container and A partition plate is provided inside the container to divide the internal space of the container into a refrigerant introduction chamber and a refrigerant discharge chamber. An inlet pipe fixed to the container and having an inlet passage connected to the refrigerant introduction chamber, At least one connecting pipe having a connecting passage that penetrates the partition plate and connects the refrigerant introduction chamber and the refrigerant discharge chamber, The container comprises at least one outlet pipe fixed to the container and having an outlet passage connected to the refrigerant discharge chamber, The at least one connecting pipe has an outlet opening that is located in the refrigerant discharge chamber. The at least one outlet pipe has an inlet opening that is located in the refrigerant discharge chamber, An accumulator in which the inlet opening of the at least one outlet pipe is positioned above the outlet opening of the at least one connecting pipe, and which can be installed such that the inlet opening of the at least one outlet pipe does not overlap with the outlet opening of the at least one connecting pipe in the vertical direction.

2. The container is cylindrical in shape, having a cylindrical body, an upper end plate that closes one end of the body, and a lower end plate that closes the other end of the body. The inlet pipe is fixed to the upper end plate, The outlet pipe is fixed to the lower end plate, The inner portion of the outlet pipe of the container, the inlet pipe, and the connecting pipe are straight pipes extending in a direction along the centerline of the shell, The inlet opening of the outlet pipe faces the partition plate upward, The accumulator according to claim 1, wherein the outlet opening of the connecting pipe faces downwards toward the lower end plate.

3. The accumulator according to claim 2, wherein the inlet opening of the outlet pipe is closer to the partition plate than the lower end plate.

4. The at least one connecting pipe has an inlet opening that is located in the refrigerant introduction chamber. The accumulator according to claim 2, wherein the inlet opening of the connecting pipe is closer to the upper end plate than the partition plate.

5. The aforementioned at least one connecting pipe is composed of multiple connecting pipes, Each of the aforementioned connecting pipes has an inlet opening located in the refrigerant introduction chamber, The accumulator according to claim 1, wherein the inlet openings of the plurality of connecting pipes can be arranged at substantially the same height.

6. The accumulator according to claim 1, wherein the at least one outlet pipe is composed of a plurality of outlet pipes.

7. The sum of the cross-sectional areas of the aforementioned connecting channels is greater than or equal to the sum of the cross-sectional areas of the inlet channels, and greater than or equal to 1.2 times the sum of the cross-sectional areas of the outlet channels. The accumulator according to claim 1, wherein the sum of the cross-sectional areas of the inlet channels is greater than the sum of the cross-sectional areas of the outlet channels.

8. A sealed container, A compression mechanism housed in the aforementioned sealed container, An electric motor housed in the sealed container generates the driving force for the compression mechanism, A compressor comprising an accumulator according to any one of claims 1 to 7, which is disposed outside the sealed container and connected to the suction side of the compression mechanism.

9. The compressor according to claim 8, Heat sink and, Expansion device and Heat absorber and A refrigeration cycle apparatus comprising a compressor, a heat sink, an expansion device, and a heat absorber, connected to a refrigerant piping for circulating the refrigerant.