Air conditioner

Abstract

An air conditioner includes switching valves that switch a circulation path of refrigerant circuit between an operation in which an indoor heat exchanger and a heat storage heat exchanger function as a condenser and an outdoor heat exchanger functions as an evaporator and another operation in which the indoor heat exchanger and the outdoor heat exchanger function as a condenser and the heat storage heat exchanger functions as an evaporator, a first flow path that connects the indoor heat exchanger and the outdoor heat exchanger, a second flow path that connects the heat storage heat exchanger and a branch portion in the first flow path, a first expansion valve that adjusts a flow rate of a refrigerant flowing between the indoor heat exchanger and the branch portion, and a second expansion valve that decompresses a refrigerant passing between the indoor heat exchanger and the first expansion valve.

Description

FIELD

[0001] Embodiments of the present invention relate to an air conditioner.BACKGROUND

[0002] An air conditioner including a heat storage heat exchanger that exchanges heat between a refrigerant discharged from a compressor and a heat storage material is known (Patent Literature 1). Such an air conditioner can execute a heat storage heating operation for heating the heat storage material while continuing the heating operation, and a defrosting heating operation for melting the frost generated in the outdoor heat exchanger while continuing the heating operation using the heat of the heat storage material. In this conventional technique, during the heat storage heating operation, the indoor heat exchanger and the heat storage heat exchanger are used as a condenser, and the outdoor heat exchanger is used as an evaporator. In addition, during the defrosting heating operation, the indoor heat exchanger and the outdoor heat exchanger are condenser, and the heat storage heat exchanger is evaporator.CITATION LISTPatent Literature

[0003] Patent Literature 1: Japanese Laid-open Patent Publication No. 2016-17738SUMMARYTechnical Problem

[0004] However, in such an air conditioner, the amount of the liquid-phase refrigerant retained in the heat exchanger functioning as the condenser during the defrosting heating operation is larger than that during the heat storage heating operation. Specifically, even if the supercooling degree of the refrigerant on the condenser outlet side is the same, as the volume of the refrigerant flow path in the heat exchanger functioning as the condenser is larger, the region filled with the liquid-phase refrigerant in the refrigerant path of the heat exchanger is larger. In addition, the heat storage heat exchanger and the outdoor heat exchanger are formed such that a volume of the outdoor heat exchanger is larger than a volume of the heat storage heat exchanger due to a difference in a heat medium that exchanges heat with the refrigerant. In the heat storage heating operation, the heat storage heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator. On the other hand, in the defrosting heating operation, the heat storage heat exchanger functions as an evaporator, and the outdoor heat exchanger functions as a condenser. At this time, the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger functioning as the condenser during the defrosting heating operation is larger than the amount of the liquid-phase refrigerant retained in the heat storage heat exchanger functioning as the condenser during the heat storage heating operation. Therefore, in a case where the refrigerant is charged based on the amount of refrigerant used during the heat storage heating operation, a large amount of the liquid-phase refrigerant retains in the outdoor heat exchanger during the defrosting heating operation, such that the flow rate of the refrigerant flowing into the indoor heat exchanger decreases and the heating capability deteriorates.

[0005] The disclosed technology has been made in view of such a problem, and an object of the disclosed technology is to provide an air conditioner that suppresses deterioration of indoor heating capability during a defrosting heating operation.Solution to Problem

[0006] According to an aspect of an embodiment, an air conditioner includes a compressor that compresses a refrigerant, an indoor heat exchanger that exchanges heat between indoor air and a refrigerant, an outdoor heat exchanger that exchanges heat between outside air and a refrigerant, a heat storage heat exchanger that exchanges heat between a heat storage material and a refrigerant, a plurality of switching valves that switches a circulation path of a refrigerant circuit in which a the refrigerant circulates between a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as a condenser and the outdoor heat exchanger function as an evaporator and a defrosting heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as a condenser and the heat storage heat exchanger function as an evaporator, a first flow path that connects the indoor heat exchanger and the outdoor heat exchanger, a branch portion that is provided in a middle of the first flow path, a second flow path that connects the heat storage heat exchanger and the branch portion, a first expansion valve that adjusts a flow rate of a refrigerant flowing through a portion of the first flow path between the indoor heat exchanger and the branch portion, and a second expansion valve that is provided between the indoor heat exchanger and the first expansion valve of the first flow path and decompresses aADVANTAGEOUS EFFECTS OF INVENTION

[0007] The air conditioner according to the disclosure can suppress deterioration of heating capability during defrosting heating operation.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a refrigerant circuit diagram illustrating an air conditioner according to an embodiment.

[0009] FIG. 2 is a block diagram illustrating the air conditioner.

[0010] FIG. 3 is a refrigerant circuit diagram illustrating the air conditioner according to the embodiment when normal heating operation is executed.

[0011] FIG. 4 is a refrigerant circuit diagram illustrating the air conditioner according to the embodiment when heat storage heating operation is executed.

[0012] FIG. 5 is a refrigerant circuit diagram illustrating the air conditioner according to the embodiment when defrosting heating operation is executed.DESCRIPTION OF EMBODIMENTS

[0013] Hereinafter, an air conditioner according to an embodiment disclosed in the present application will be described in detail with reference to the drawings. Note that the technology of the present disclosure is not limited by the following description. In addition, in the following description, the same components are denoted by the same reference numerals, and redundant description is omitted.Embodiments

[0014] FIG. 1 is a refrigerant circuit diagram illustrating an air conditioner 1 according to an embodiment. The air conditioner 1 of the embodiment includes an outdoor equipment 2 and an indoor equipment 3. The outdoor equipment 2 is installed outdoors. The indoor equipment 3 is installed in a room that is cooled and heated by the air conditioner 1. The air conditioner 1 further includes a refrigerant circuit 5. The refrigerant circuit 5 includes an indoor heat exchanger 6, an outdoor heat exchanger 7, and a heat storage heat exchanger 8, and includes a first refrigerant pipe 11 (first flow path) and a second refrigerant pipe 12 (second flow path). The indoor heat exchanger 6 is disposed inside the indoor equipment 3. The outdoor heat exchanger 7 is disposed inside the outdoor equipment 2 and is connected to the indoor heat exchanger 6 via the first refrigerant pipe 11. The in-pipe volume of the refrigerant flow path of the outdoor heat exchanger 7 is larger than the in-pipe volume of the refrigerant flow path of the indoor heat exchanger 6. The heat storage heat exchanger 8 is disposed inside the outdoor equipment 2 and is connected to a first branch portion 14 (branch portion) provided in the middle of the first refrigerant pipe 11 via the second refrigerant pipe 12. The in-pipe volume of the refrigerant flow path of the heat storage heat exchanger 8 is larger than the in-pipe volume of the refrigerant flow path of the indoor heat exchanger 6 and smaller than the in-pipe volume of the refrigerant flow path of the outdoor heat exchanger 7, The heat storage heat exchanger 8 includes a heat storage material 18.

[0015] The refrigerant circuit 5 further includes an outdoor equipment expansion valve 15 (first expansion valve), an indoor equipment expansion valve 16 (second expansion valve), and a heat storage heat exchange side expansion valve 17 (fourth expansion valve). The outdoor equipment expansion valve 15 is disposed inside the outdoor equipment 2 and is provided between the indoor heat exchanger 6 and the first branch portion 14 of the first refrigerant pipe 11. The outdoor equipment expansion valve 15 adjusts the flow rate of the refrigerant flowing through the portion between the indoor heat exchanger 6 and the first branch portion 14. The indoor equipment expansion valve 16 is disposed inside the indoor equipment 3 and is provided between the indoor heat exchanger 6 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11. At this time, in the air conditioner 1, as compared with other air conditioners in which both the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 are arranged in only one of the outdoor equipment 2 and the indoor equipment 3, the pressure loss can be reduced by allowing the refrigerant decompressed and reduced in pressure to flow through a flow path portion 19 between the indoor equipment expansion valve 16 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11. Therefore, the length of the portion can be increased, and the in-pipe volume of the refrigerant flow path of a flow path portion 19 can be increased. The heat storage heat exchange side expansion valve 17 is disposed inside the outdoor equipment 2 and is provided in the middle of the second refrigerant pipe 12.

[0016] The refrigerant circuit 5 further includes compressor 21, a plurality of switching valves 22, a third refrigerant pipe 23 (third flow path), a fourth refrigerant pipe 24 (fourth flow path), and a connection pipe side expansion valve 25 (fourth expansion valve), The compressor 21 is disposed inside the outdoor equipment 2 and includes a suction pipe 31 and a discharge pipe 32. The compressor 21 compresses a gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31, and discharges the compressed gas-phase refrigerant to the discharge pipe 32 to circulate the refrigerant in the refrigerant circuit 5.

[0017] The plurality of switching valves 22 is disposed inside the outdoor equipment 2, and include an indoor heat exchange side three-way valve 26, an outdoor heat exchange side three-way valve 27, and a heat storage heat exchange side three-way valve 28. The indoor heat exchange side three-way valve 26 is connected to the indoor heat exchanger 6, and is connected to the suction pipe 31 of the compressor 21. The indoor heat exchange side three-way valve 26 is further connected to the discharge pipe 32 of the compressor 21 via the third refrigerant pipe 23. The outdoor heat exchange side three-way valve 27 is connected to the outdoor heat exchanger 7, and is connected to the suction pipe 31 of the compressor 21. The outdoor heat exchange side three-way valve 27 is further connected to a second branch portion 33 provided in the middle of the third refrigerant pipe 23 via the fourth refrigerant pipe 24. The heat storage heat exchange side three-way valve 28 is connected to the heat storage heat exchanger 8, and is connected to the suction pipe 31 of the compressor 21. The heat storage heat exchange side three-way valve 28 is further connected to a third branch portion 34 provided in the middle of the fourth refrigerant pipe 24. The connection pipe side expansion valve 25 is disposed inside the outdoor equipment 2 and is provided between the second branch portion 33 and the third branch portion 34 of the fourth refrigerant pipe 24.

[0018] The plurality of switching valves 22 is switched to a normal heating position, a heat storage heating position, a defrosting heating position, and a cooling position. When the plurality of switching valves 22 is switched to the normal heating position, the discharge pipe 32 is connected to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, the connection pipe side expansion valve 25 is connected to the heat storage heat exchanger 8 via the heat storage heat exchange side three-way valve 28, and the outdoor heat exchanger 7 is connected to the suction pipe 31 via the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the heat storage heating position, the discharge pipe 32 is connected to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, the connection pipe side expansion valve 25 is connected to the heat storage heat exchanger 8 via the heat storage heat exchange side three-way valve 28, and the outdoor heat exchanger 7 is connected to the suction pipe 31 via the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the defrosting heating position, the discharge pipe 32 is connected to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, the connection pipe side expansion valve 25 is connected to the outdoor heat exchanger 7 via the outdoor heat exchange side three-way valve 27, and the heat storage heat exchanger 8 is connected to the suction pipe 31 via the heat storage heat exchange side three-way valve 28. When the plurality of switching valves 22 is switched to the cooling position, the connection pipe side expansion valve 25 is connected to the outdoor heat exchanger 7 via the outdoor heat exchange side three-way valve 27, and the indoor heat exchanger 6 is connected to the suction pipe 31 via the indoor heat exchange side three-way valve 26.

[0019] As illustrated in FIG. 2, the air conditioner 1 further includes a control device 41 (control unit). FIG. 2 is a block diagram illustrating the air conditioner 1.

[0020] The control device 41 is disposed inside the outdoor equipment 2 and includes a storage device 42 and a central processing unit (CPU) 43. The storage device 42 stores a computer program installed in the control device 41, and stores information used by the CPU 43. By executing a computer program installed in the control device 41, the CPU 43 controls the indoor heat exchange side three-way valve 26, the outdoor heat exchange side three-way valve 27, the heat storage heat exchange side three-way valve 28, the outdoor equipment expansion valve 15, the indoor equipment expansion valve 16, the heat storage heat exchange side expansion valve 17, and the connection pipe side expansion valve 25.

[0021] The operation executed by the air conditioner 1 includes a normal heating operation, a heat storage heating operation, a defrosting heating operation, and a cooling operation.[Normal Heating Operation]

[0022] The normal heating operation is executed, for example, when the user operates the air conditioner 1 to execute the normal heating operation. When the air conditioner 1 executes the normal heating operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the normal heating position. The control device 41 further controls the indoor equipment expansion valve 16 when the air conditioner 1 executes the normal heating operation. The opening degree of the indoor equipment expansion valve 16 is reduced by, for example, target discharge temperature control which is a known technique. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the outdoor equipment expansion valve 15 to fully open the opening degree of the outdoor equipment expansion valve 15. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the connection pipe side expansion valve 25 to reduce the opening degree of the connection pipe side expansion valve 25 to a predetermined opening degree. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to reduce the opening degree of the heat storage heat exchange side expansion valve 17 to a predetermined opening degree. At this time, the heat storage heat exchange side expansion valve 17 and the connection pipe side expansion valve 25 are controlled such that the decompression amount by which the heat storage heat exchange side expansion valve 17 decompresses the refrigerant is smaller than the decompression amount by which the connection pipe side expansion valve 25 decompresses the refrigerant, thereby suppressing excessive accumulation of the refrigerant in the second refrigerant pipe 12 including the heat storage heat exchanger 8.

[0023] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 flows into the indoor heat exchange side three-way valve 26 and also flows into the connection pipe side expansion valve 25.

[0024] The high-pressure gas-phase refrigerant that has flowed into the indoor heat exchange side three-way valve 26 flows into the indoor heat exchanger 6 when the plurality of switching valves 22 is switched to the normal heating position. The indoor heat exchanger 6 exchanges heat between the high-pressure gas-phase refrigerant flowing into the indoor heat exchanger 6 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air heated by the indoor heat exchanger 6 into the room to heat the room. The high-pressure gas-phase refrigerant subjected to heat exchange with air in a room by the indoor heat exchanger 6 is cooled and condensed by the indoor heat exchanger 6 to become a supercooled high-pressure liquid-phase refrigerant. That is, the indoor heat exchanger 6 functions as a condenser when the air conditioner 1 executes the normal heating operation.

[0025] The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor equipment expansion valve 16. Since the opening degree of the indoor equipment expansion valve 16 is reduced to a predetermined opening degree, a flow rate of the refrigerant flowing from the indoor heat exchanger 6 to the outdoor heat exchanger 7 is adjusted, and the high-pressure liquid-phase refrigerant flowing into the indoor equipment expansion valve 16 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the indoor equipment expansion valve 16 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the indoor equipment expansion valve 16 flows into the outdoor equipment expansion valve 15. The low-pressure gas-liquid two-phase refrigerant that has flowed into the outdoor equipment expansion valve 15 flows into the outdoor heat exchanger 7 as the low-pressure gas-liquid two-phase refrigerant by the opening degree of the outdoor equipment expansion valve 15 being fully opened. Therefore, as illustrated in FIG. 3, the flow path portion 19 between the indoor equipment expansion valve 16 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11 is filled with a gas-liquid two-phase refrigerant. FIG. 3 is a refrigerant circuit diagram illustrating the air conditioner 1 according to the embodiment when normal heating operation is executed. In FIG. 3, the flow path through which the liquid-phase refrigerant flows is indicated by a thick line.

[0026] Since the opening degree of the connection pipe side expansion valve 25 is reduced to a predetermined opening degree, the flow rate of the refrigerant flowing through the connection pipe side expansion valve 25 is adjusted such that the flow rate of the refrigerant flowing through the heat storage heat exchanger 8 becomes smaller than the flow rate of the refrigerant flowing through the indoor heat exchanger 6, and the high-pressure gas-phase refrigerant flowing into the connection pipe side expansion valve 25 is slightly decompressed. The high-pressure gas-phase refrigerant decompressed by the connection pipe side expansion valve 25 flows into the heat storage heat exchange side three-way valve 28. The high-pressure gas-phase refrigerant that has flowed into the heat storage heat exchange side three-way valve 28 flows into the heat storage heat exchanger 8 when the plurality of switching valves 22 is switched to the normal heating position. The heat storage heat exchanger 8 exchanges heat between the high-pressure gas-phase refrigerant flowing into the heat storage heat exchanger 8 and the heat storage material 18. The heat storage material 18 subjected to heat exchange with the high-pressure gas-phase refrigerant by the heat storage heat exchanger 8 is heated and stores heat. The high-pressure gas-phase refrigerant subjected to heat exchange with the heat storage material 18 by the heat storage heat exchanger 8 is cooled and condensed to become a supercooled high-pressure liquid-phase refrigerant. That is, the heat storage heat exchanger 8 functions as a condenser when the air conditioner 1 executes the normal heating operation.

[0027] The high-pressure liquid-phase refrigerant flowing out of the heat storage heat exchanger 8 flows into the heat storage heat exchange side expansion valve 17. The opening degree of the heat storage heat exchange side expansion valve 17 is reduced to a predetermined opening degree, such that the high-pressure liquid-phase refrigerant flowing in from the heat storage heat exchanger 8 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the heat storage heat exchange side expansion valve17 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the heat storage heat exchange side expansion valve 17 flows into the outdoor heat exchanger 7.

[0028] The outdoor heat exchanger 7 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the outdoor equipment expansion valve 15 and the heat storage heat exchange side expansion valve 17 and outside air. The low-pressure gas-liquid two-phase refrigerant is heated by the outdoor heat exchanger 7 to become a low-pressure gas-phase refrigerant. That is, the outdoor heat exchanger 7 functions as an evaporator when the air conditioner 1 executes the normal heating operation. The low-pressure gas-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the heating position, the low-pressure gas-phase refrigerant flowing into the outdoor heat exchange side three-way valve 27 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.

[0029] In the air conditioner 1, when the normal heating operation is executed, the refrigerant having a flow rate smaller than the flow rate of the refrigerant flowing through the indoor heat exchanger 6 flows through the heat storage heat exchanger 8, such that the amount of the refrigerant retained in the heat storage heat exchanger 8 can be reduced. The air conditioner 1 can suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 by reducing the amount of the refrigerant retained in the heat storage heat exchanger 8, and can suppress deterioration of heating capability.[Heat storage heating operation]

[0030] The heat storage heating operation is started, for example, when the normal heating operation is executed and a heat load due to heating is smaller than a predetermined threshold value. When the air conditioner 1 executes the heat storage heating operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the normal heat storage heating position. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the indoor equipment expansion valve 16 to fully open the opening degree of the indoor equipment expansion valve 16. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the outdoor equipment expansion valve 15 to reduce the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the connection pipe side expansion valve 25 to fully open the opening degree of the connection pipe side expansion valve 25. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to reduce the opening degree of the heat storage heat exchange side expansion valve 17 to a predetermined opening degree.

[0031] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 is supplied to the indoor heat exchange side three-way valve 26, and flows into the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant that has flowed into the indoor heat exchange side three-way valve 26 flows into the indoor heat exchanger 6 when the plurality of switching valves 22 is switched to the heat storage heating position.

[0032] The indoor heat exchanger 6 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the plurality of switching valves 22 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air heated by the indoor heat exchanger 6 into the room to heat the room. The high-pressure gas-phase refrigerant subjected to heat exchange by the indoor heat exchanger 6 is cooled to become a supercooled high-pressure liquid-phase refrigerant. That is, the indoor heat exchanger 6 functions as a condenser when the air conditioner 1 executes the heat storage heating operation.

[0033] The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor equipment expansion valve 16. The high-pressure liquid-phase refrigerant having flowed into the indoor equipment expansion valve 16 flows into the outdoor equipment expansion valve 15 as the high-pressure liquid-phase refrigerant without being decompressed by the indoor equipment expansion valve 16 since the opening degree of the indoor equipment expansion valve 16 is fully opened. The outdoor equipment expansion valve 15 reduces the pressure of the high-pressure liquid-phase refrigerant flowing in from the indoor equipment expansion valve 16 by reducing the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. The high-pressure liquid-phase refrigerant is decompressed by the outdoor equipment expansion valve 15 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the outdoor equipment expansion valve 15 flows into the outdoor heat exchanger 7. Therefore, as illustrated in FIG. 4, a space between the outdoor equipment expansion valve 15 of the first refrigerant pipe 11 and the outdoor heat exchanger 7 is filled with a low-pressure gas-liquid two-phase refrigerant having a low density, and the flow path portion 19 is filled with a high-pressure liquid-phase refrigerant having a high density. FIG. 4 is a refrigerant circuit diagram illustrating the air conditioner 1 according to the embodiment when heat storage heating operation is executed. In FIG. 4, the flow path through which the liquid-phase refrigerant flows is indicated by a

[0034] The high-pressure gas-phase refrigerant having flowed into the connection pipe side expansion valve 25 flows into the heat storage heat exchange side three-way valve 28 as the high-pressure gas-phase refrigerant without being decompressed since the opening degree of the connection pipe side expansion valve 25 is fully opened. The high-pressure gas-phase refrigerant that has flowed into the heat storage heat exchange side three-way valve 28 flows into the heat storage heat exchanger 8 when the plurality of switching valves 22 is switched to the heat storage heating position. The heat storage heat exchanger 8 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the heat storage heat exchange side three-way valve 28 and the heat storage material 18. The heat storage material 18 stores heat by being heated by the heat storage heat exchanger 8. The high-pressure gas-phase refrigerant subjected to heat exchange with the heat storage material 18 by the heat storage heat exchanger 8 is cooled and condensed by the heat storage heat exchanger 8 to become a supercooled high-pressure liquid-phase refrigerant. That is, the heat storage heat exchanger 8 functions as a condenser when the air conditioner 1 executes the heat storage heating operation. The high-pressure liquid-phase refrigerant flowing out of the heat storage heat exchanger 8 flows into the heat storage heat exchange side expansion valve 17. The opening degree of the heat storage heat exchange side expansion valve 17 is reduced to a predetermined opening degree, such that the high-pressure liquid-phase refrigerant flowing into the heat storage heat exchange side expansion valve 17 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the heat storage heat exchange side expansion valve 17 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the heat storage heat exchange side expansion valve 17 flows into the outdoor heat exchanger 7.

[0035] The outdoor heat exchanger 7 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the outdoor equipment expansion valve 15 and the heat storage heat exchange side expansion valve 17 and outside air. The low-pressure gas-liquid two-phase refrigerant is heated by the outdoor heat exchanger 7 to become a low-pressure gas-phase refrigerant. That is, the outdoor heat exchanger 7 functions as an evaporator when the air conditioner 1 executes the heat storage heating operation. The low-pressure gas-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the heat storage heating position, the low-pressure gas-phase refrigerant flowing into the outdoor heat exchange side three-way valve 27 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.

[0036] When the amount of the refrigerant flowing through the refrigerant circuit 5 is excessive, the area filled with the liquid-phase refrigerant in the refrigerant flow path inside the indoor heat exchanger 6 increases, such that the area using latent heat in the indoor heat exchanger 6 decreases, and thus the amount of heat exchange may decrease. That is, the heating capability of the air conditioner 1 may deteriorate. The air conditioner 1 can retain the liquid-phase refrigerant in the flow path portion 19 when the heat storage heating operation is executed. In addition, the air conditioner 1 can retain a large amount of liquid-phase refrigerant in the flow path portion 19 due to the large in-pipe volume of the refrigerant flow path of the flow path portion 19. When the heat storage heating operation is executed, the air conditioner 1 retains the liquid-phase refrigerant in the flow path portion 19, such that the amount of the refrigerant flowing through the indoor heat exchanger 6 can be suppressed from becoming excessive, and the heating capability can be suppressed from deteriorating,[Defrosting Heating Operation]

[0037] The defrosting heating operation is executed, for example, after the heat storage heating operation is performed, when heat is stored in the heat storage material 18, and when frost is formed on the outdoor heat exchanger 7. When the air conditioner 1 executes the defrosting heating operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the defrosting heating position. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the indoor equipment expansion valve 16 to reduce the opening degree of the indoor equipment expansion valve 16 to a predetermined opening degree. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the outdoor equipment expansion valve 15 to fully open the opening degree of the outdoor equipment expansion valve 15. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the connection pipe side expansion valve 25 to reduce the opening degree of the connection pipe side expansion valve 25 to a predetermined opening degree. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to reduce the opening degree of the heat storage heat exchange side expansion valve 17 to a predetermined opening degree.

[0038] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 is supplied to the indoor heat exchange side three-way valve 26, and flows into the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant that has flowed into the indoor heat exchange side three-way valve 26 flows into the indoor heat exchanger 6 when the plurality of switching valves 22 is switched to the defrosting heating position. The indoor heat exchanger 6 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the plurality of switching valves 22 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air heated by the indoor heat exchanger 6 into the room to heat the room. The high-pressure gas-phase refrigerant is cooled and condensed in the indoor heat exchanger 6 to become a high-pressure liquid-phase refrigerant in a supercooled state. That is, the indoor heat exchanger 6 functions as a condenser when the air conditioner 1 executes the defrosting heating operation.

[0039] The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor equipment expansion valve 16. The indoor equipment expansion valve 16 reduces the pressure of the high-pressure liquid-phase refrigerant flowing in from the indoor heat exchanger 6 by reducing the opening degree of the indoor equipment expansion valve 16 to a predetermined opening degree. The high-pressure liquid-phase refrigerant is decompressed by the indoor equipment expansion valve 16 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the indoor equipment expansion valve 16 flows into the outdoor equipment expansion valve 15. The low-pressure gas-liquid two-phase refrigerant that has flowed into the outdoor equipment expansion valve 15 is not decompressed by the outdoor equipment expansion valve 15 because the outdoor equipment expansion valve 15 is fully opened, and flows into the heat storage heat exchange side expansion valve 17 as the low-pressure gas-liquid two-phase refrigerant. Therefore, as illustrated in FIG. 5, a space between the indoor heat exchanger 6 and the indoor equipment expansion valve 16 of the first refrigerant pipe 11 is filled with the high-pressure liquid-phase refrigerant, and the flow path portion 19 is filled with the low-pressure gas-liquid two-phase refrigerant. FIG. 5 is a refrigerant circuit diagram illustrating the air conditioner 1 according to the embodiment when defrosting heating operation is executed. In FIG. 5, the flow path through which the liquid-phase refrigerant flows is indicated by a thick line.

[0040] The connection pipe side expansion valve 25 slightly decompresses the high-pressure gas-phase refrigerant flowing into the connection pipe side expansion valve 25 by reducing the opening degree of the connection pipe side expansion valve 25 to a predetermined opening degree. The high-pressure gas-phase refrigerant decompressed by the connection pipe side expansion valve 25 flows into the outdoor heat exchange side three-way valve 27. The high-pressure gas-phase refrigerant that has flowed into the outdoor heat exchange side three-way valve 27 flows into the outdoor heat exchanger 7 when the plurality of switching valves 22 is switched to the defrosting heating position.

[0041] The outdoor heat exchanger 7 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the outdoor heat exchange side three-way valve 27 and frost formed on the outdoor heat exchanger 7. The frost formed on the outdoor heat exchanger 7 is heated and melted. At this time, the air conditioner 1 can cause the refrigerant having the temperature for defrosting to flow into the outdoor heat exchanger 7 by the amount of the refrigerant decompressed by the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant subjected to heat exchange with the frost formed by the outdoor heat exchanger 7 is cooled and condensed to become a supercooled high-pressure liquid-phase refrigerant. That is, the outdoor heat exchanger 7 functions as a condenser when the air conditioner 1 executes the defrosting heating operation. The outdoor heat exchanger 7 functions as a condenser to retain the liquid-phase refrigerant inside the outdoor heat exchanger 7. At this time, since the connection pipe side expansion valve 25 decompresses the refrigerant, the temperature of the refrigerant flowing through the outdoor heat exchanger 7 is low, and the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7 is small. The high-pressure liquid-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the heat storage heat exchange side expansion valve 17.

[0042] The opening degree of the heat storage heat exchange side expansion valve 17 is reduced to a predetermined opening degree, such that the high-pressure liquid-phase refrigerant flowing in from the indoor heat exchanger 6 and the outdoor heat exchanger 7 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the heat storage heat exchange side expansion valve 17 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the heat storage heat exchange side expansion valve 17 flows into the heat storage heat exchanger 8.

[0043] The heat storage heat exchanger 8 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the heat storage heat exchange side expansion valve 17 and the heat storage material 18. The low-pressure gas-liquid two-phase refrigerant heat-exchanged with the heat storage material 18 by the heat storage heat exchanger 8 is heated to become a low-pressure gas-phase refrigerant. That is, the heat storage heat exchanger 8 functions as an evaporator when the air conditioner 1 executes the defrosting heating operation. The low-pressure gas-phase refrigerant flowing out of the heat storage heat exchanger 8 flows into the heat storage heat exchange side three-way valve 28. When the plurality of switching valves 22 is switched to the defrosting heating position, the low-pressure gas-phase refrigerant flowing into the heat storage heat exchange side three-way valve 28 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.

[0044] In the air conditioner 1, the liquid-phase refrigerant stored in the flow path portion 19 during the heat storage heating operation is retained in the outdoor heat exchanger 7 when the defrosting heating operation is executed. As a result, it is possible to suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6, and can suppress deterioration of heating capability.[Cooling Operation]

[0045] The cooling operation is executed, for example, when the user operates the air conditioner 1 to execute the cooling operation. When the air conditioner 1 executes the cooling operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the cooling position. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the connection pipe side expansion valve 25 to fully open the opening of the connection pipe side expansion valve 25. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to fully close the opening degree of the heat storage heat exchange side expansion valve 17. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the outdoor equipment expansion valve 15 to reduce the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the indoor equipment expansion valve 16 to fully open the opening degree of the indoor equipment expansion valve 16.

[0046] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 flows into the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant having flowed into the connection pipe side expansion valve 25 flows into the outdoor heat exchange side three-way valve 27 as the high-pressure gas-phase refrigerant without being decompressed since the opening degree of the connection pipe side expansion valve 25 is fully opened. The high-pressure gas-phase refrigerant that has flowed into the outdoor heat exchange side three-way valve 27 flows into the outdoor heat exchanger 7 when the plurality of switching valves 22 is switched to the cooling position. The outdoor heat exchanger 7 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the plurality of switching valves 22 and outside air. The high-pressure gas-phase refrigerant is cooled and condensed in the outdoor heat exchanger 7 to become a high-pressure liquid-phase refrigerant in a supercooled state. That is, the outdoor heat exchanger 7 functions as a condenser when the air conditioner 1 executes the cooling operation.

[0047] The high-pressure liquid-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the outdoor equipment expansion valve 15. The outdoor equipment expansion valve 15 reduces the pressure of the high-pressure liquid-phase refrigerant flowing in from the outdoor heat exchanger 7 by reducing the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. The high-pressure liquid-phase refrigerant is decompressed by the outdoor equipment expansion valve 15 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the outdoor equipment expansion valve 15 flows into the indoor equipment expansion valve 16. The low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor equipment expansion valve 16 is not decompressed by the indoor equipment expansion valve 16 because the indoor equipment expansion valve 16 is fully opened, and flows into the indoor heat exchanger 6 as the low-pressure gas-liquid two-phase refrigerant.

[0048] The indoor heat exchanger 6 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the indoor equipment expansion valve 16 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air cooled by the indoor heat exchanger 6 into the room to cool the room. The low-pressure gas-liquid two-phase refrigerant is heated by the indoor heat exchanger 6 to become a low-pressure gas-phase refrigerant. That is, the indoor heat exchanger 6 functions as an evaporator when the air conditioner 1 executes the cooling operation. The low-pressure gas-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor heat exchange side three-way valve 26. When the plurality of switching valves 22 is switched to the cooling position, the low-pressure gas-phase refrigerant flowing into the indoor heat exchange side three-way valve 26 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.[Effects of Air Conditioner 1 According to Embodiment]

[0049] The air conditioner 1 according to the embodiment includes the refrigerant circuit 5 through which the refrigerant circulates. The refrigerant circuit 5 is provided with the compressor 21, the indoor heat exchanger 6, the outdoor heat exchanger 7, the heat storage heat exchanger 8, the plurality of switching valves 22, the first refrigerant pipe 11, the first branch portion 14, the second refrigerant pipe 12, the outdoor equipment expansion valve 15, and the indoor equipment expansion valve 16. The compressor 21 compresses a refrigerant. The indoor heat exchanger 6 exchanges heat between air in a room and a refrigerant. The outdoor heat exchanger 7 exchanges heat between outside air and a refrigerant. The heat storage heat exchanger 8 exchanges heat between the heat storage material 18 and a refrigerant. The plurality of switching valves 22 switches the circulation path of the refrigerant in the refrigerant circuit 5 between the heat storage heating operation and the defrosting heating operation. In the heat storage heating operation, the indoor heat exchanger 6 and the heat storage heat exchanger 8 are caused to function as condensers, and the outdoor heat exchanger 7 is caused to function as an evaporator. In the defrosting heating operation, the indoor heat exchanger 6 and the outdoor heat exchanger 7 are caused to function as condensers, and the heat storage heat exchanger 8 is caused to function as an evaporator. The first refrigerant pipe 11 connects the indoor heat exchanger 6 and the outdoor heat exchanger 7. The first branch portion 14 is provided in the middle of the first refrigerant pipe 11. The second refrigerant pipe 12 connects the heat storage heat exchanger 8 and the first branch portion 14. The outdoor equipment expansion valve 15 decompresses the refrigerant flowing through the portion of the first refrigerant pipe 11 between the indoor heat exchanger 6 and the first branch portion 14. The indoor equipment expansion valve 16 is provided between the indoor heat exchanger 6 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11, and decompresses the passing refrigerant.

[0050] In addition, the air conditioner 1 according to the embodiment further includes the control device 41 that controls the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 such that the liquid-phase refrigerant flows to the flow path portion 19 between the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 of the first refrigerant pipe 11 when the heat storage heating operation is executed. The control device 41 further controls the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 such that the gas-liquid two-phase refrigerant flows in the flow path portion 19 when the defrosting heating operation is executed.

[0051] The amount of the refrigerant flowing into the indoor heat exchanger 6 is reduced by the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7 when the defrosting heating operation is executed. When the amount of the refrigerant flowing into the indoor heat exchanger 6 is insufficient, the air conditioner 1 may have a deteriorated heating capability. The air conditioner 1 according to the embodiment can increase the amount of refrigerant flowing into the indoor heat exchanger 6 when the defrosting heating operation is executed by the amount of refrigerant retained in the flow path portion 19 when the heat storage heating operation is executed. Therefore, the air conditioner 1 according to the embodiment can suppress a decrease in the amount of the refrigerant flowing into the indoor heat exchanger 6 when the defrosting heating operation is executed, and can suppress deterioration of heating capability.

[0052] In addition, the air conditioner 1 according to the embodiment further includes the third refrigerant pipe 23, the fourth refrigerant pipe 24, and the connection pipe side expansion valve 25. The third refrigerant pipe 23 supplies the refrigerant compressed by the compressor 21 to the indoor heat exchanger 6 when the indoor heat exchanger 6 functions as a condenser. The fourth refrigerant pipe 24 supplies the compressed refrigerant to the outdoor heat exchanger 7 when the outdoor heat exchanger 7 functions as a condenser. The connection pipe side expansion valve 25 decompresses the refrigerant flowing through the fourth refrigerant pipe 24.

[0053] In addition, the control device 41 of the air conditioner 1 according to the embodiment controls the connection pipe side expansion valve 25 such that the pressure of the refrigerant flowing through the outdoor heat exchanger 7 becomes lower than the pressure of the refrigerant flowing through the indoor heat exchanger 6 when the defrosting heating operation is executed. The air conditioner 1 according to the embodiment can reduce the temperature of the refrigerant flowing through the outdoor heat exchanger 7 when the defrosting heating operation is executed, and can reduce the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7. The air conditioner 1 according to the embodiment reduces the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7 when the defrosting heating operation is executed, thereby suppressing a decrease in the amount of the refrigerant flowing into the indoor heat exchanger 6 and suppressing deterioration of heating capability. In addition, the air conditioner 1 according to the embodiment can decompress the refrigerant flowing into the heat storage heat exchanger 8 from the outdoor heat exchanger 7 when the defrosting heating operation is

[0054] In addition, the air conditioner 1 according to the embodiment further includes the heat storage heat exchange side expansion valve 17 that decompresses the refrigerant flowing through the second refrigerant pipe 12. At this time, the air conditioner 1 according to the embodiment can decompress the refrigerant flowing from the heat storage heat exchanger 8 into the outdoor heat exchanger 7 when the heat storage heating operation is executed, and can reduce the amount of the refrigerant flowing into the heat storage heat exchanger 8 to be smaller than the amount of the refrigerant flowing into the indoor heat exchanger 6. The air conditioner 1 according to the embodiment can suppress shortage of the amount of the refrigerant flowing to the indoor heat exchanger 6, and can suppress deterioration of heating capability.

[0055] In addition, the plurality of switching valves 22 of the air conditioner 1 according to the embodiment further switches the path through which the refrigerant flows such that the normal heating operation in which the indoor heat exchanger 6 functions as a condenser and the outdoor heat exchanger 7 functions as an evaporator is executed. The control device 41 controls the connection pipe side expansion valve 25 and the 17 heat storage heat exchange side expansion valve 17 such that a decompression amount at which the heat storage heat exchange side expansion valve 17 decompresses the refrigerant is smaller than a decompression amount at which the connection pipe side expansion valve 25 decompresses the refrigerant when the normal heating operation is executed. The air conditioner 1 according to the embodiment can circulate the liquid-phase refrigerant retained in the heat storage heat exchanger 8 to the refrigerant circuit 5 to reduce the liquid-phase refrigerant retained in the heat storage heat exchanger 8 when the normal heating operation is executed. The air conditioner 1 according to the embodiment reduces the amount of the liquid-phase refrigerant retained in the heat storage heat exchanger 8 when the normal heating operation is executed, thereby making it possible to suppress a shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 and suppress deterioration of heating capability.

[0056] In addition, the outdoor equipment expansion valve 15 of the air conditioner 1 according to the embodiment is provided in the outdoor equipment 2 provided with the outdoor heat exchanger 7. The indoor equipment expansion valve 16 is provided in the indoor equipment 3 provided with the indoor heat exchanger 6. In the air conditioner 1 according to the embodiment, the length of the flow path portion 19 can be made longer and the in-pipe volume of the refrigerant flow path of the flow path portion 19 can be made larger as compared with other air conditioners in which both the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 are arranged in only one of the outdoor equipment 2 and the indoor equipment 3. The air conditioner 1 according to the embodiment can increase the amount of the liquid-phase refrigerant retained in the flow path portion 19 when the heat storage heating operation is executed due to the large in-pipe volume of the refrigerant flow path of the flow path portion 19, In the air conditioner 1 according to the embodiment, the amount of the refrigerant retained in the flow path portion 19 when the heat storage heating operation is executed is large. Therefore, when the defrosting heating operation is executed, it possible to suppress a shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 and suppress deterioration of heating capability.

[0057] By the way, the air conditioner 1 according to the above-described embodiment causes the refrigerant to flow to the heat storage heat exchanger 8 when the normal heating operation is executed, but does not have to cause the refrigerant to flow to the heat storage heat exchanger 8. For example, when the air conditioner 1 executes the normal heating operation, the control device 41 controls the plurality of switching valves 22, connects the discharge pipe 32 to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, connects the outdoor heat exchanger 7 to the suction pipe 31 via the outdoor heat exchange side three-way valve 27, and connects the heat storage heat exchanger 8 to the suction pipe 31 via the heat storage heat exchange side three-way valve 28. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to fully close the opening degree of the heat storage heat exchange side expansion valve 17. Even when the liquid-phase refrigerant is retained in the heat storage heat exchanger 8 before the normal heating operation is executed, the air conditioner 1 can supply the refrigerant to the suction pipe 31 and reduce the amount of the refrigerant retained in the heat storage heat exchanger 8. The air conditioner 1 can suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 by reducing the amount of the refrigerant retained in the heat storage heat exchanger 8, similarly to the air conditioner of the above-described embodiment, and can suppress deterioration of heating capability.

[0058] By the way, the air conditioner 1 according to the above-described embodiment is formed so as to execute the cooling operation, but may be formed so as not to execute the cooling operation. Even when the cooling operation is not executed, the air conditioner 1 can suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 when the defrosting heating operation is executed, and can suppress deterioration of heating capability.

[0059] Although the embodiment has been described above, the embodiment is not limited by the contents described above. In addition, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, at least one of various omissions, substitutions, and changes of the components can be made without departing from the gist of the embodiments.REFERENCE SIGNS LIST1 AIR CONDITIONER

[0061] 2 OUTDOOR EQUIPMENT

[0062] 3 INDOOR EQUIPMENT

[0063] 5 REFRIGERANT CIRCUIT

[0064] 6 INDOOR HEAT EXCHANGER

[0065] 7 OUTDOOR HEAT EXCHANGER

[0066] 8 HEAT STORAGE HEAT EXCHANGER

[0067] 11 FIRST REFRIGERANT PIPE (FIRST FLOW PATH)

[0068] 12 SECOND REFRIGERANT PIPE (SECOND FLOW PATH)

[0069] 14 FIRST BRANCH PORTION (BRANCH PORTION)

[0070] 15 OUTDOOR EQUIPMENT EXPANSION VALVE (FIRST EXPANSION VALVE)

[0071] 16 INDOOR EQUIPMENT EXPANSION VALVE (SECOND EXPANSION VALVE)

[0072] 17 HEAT STORAGE HEAT EXCHANGE SIDE EXPANSION VALVE (FOURTH EXPANSION VALVE)

[0073] 18 HEAT STORAGE MATERIAL

[0074] 19 FLOW PATH PORTION

[0075] 21 COMPRESSOR

[0076] 22 PLURALITY OF SWITCHING VALVES

[0077] 23 THIRD REFRIGERANT PIPE (THIRD FLOW PATH)

[0078] 24 FOURTH REFRIGERANT PIPE (FOURTH FLOW PATH)

[0079] 25 CONNECTION PIPE SIDE EXPANSION VALVE (THIRD EXPANSION VALVE)

[0080] 41 CONTROL DEVICE (CONTROL UNIT)

Examples

embodiments

[0014]FIG. 1 is a refrigerant circuit diagram illustrating an air conditioner 1 according to an embodiment. The air conditioner 1 of the embodiment includes an outdoor equipment 2 and an indoor equipment 3. The outdoor equipment 2 is installed outdoors. The indoor equipment 3 is installed in a room that is cooled and heated by the air conditioner 1. The air conditioner 1 further includes a refrigerant circuit 5. The refrigerant circuit 5 includes an indoor heat exchanger 6, an outdoor heat exchanger 7, and a heat storage heat exchanger 8, and includes a first refrigerant pipe 11 (first flow path) and a second refrigerant pipe 12 (second flow path). The indoor heat exchanger 6 is disposed inside the indoor equipment 3. The outdoor heat exchanger 7 is disposed inside the outdoor equipment 2 and is connected to the indoor heat exchanger 6 via the first refrigerant pipe 11. The in-pipe volume of the refrigerant flow path of the outdoor heat exchanger 7 is larger than the in-pipe volume ...

FIELD

[0001] Embodiments of the present invention relate to an air conditioner.BACKGROUND

[0002] An air conditioner including a heat storage heat exchanger that exchanges heat between a refrigerant discharged from a compressor and a heat storage material is known (Patent Literature 1). Such an air conditioner can execute a heat storage heating operation for heating the heat storage material while continuing the heating operation, and a defrosting heating operation for melting the frost generated in the outdoor heat exchanger while continuing the heating operation using the heat of the heat storage material. In this conventional technique, during the heat storage heating operation, the indoor heat exchanger and the heat storage heat exchanger are used as a condenser, and the outdoor heat exchanger is used as an evaporator. In addition, during the defrosting heating operation, the indoor heat exchanger and the outdoor heat exchanger are condenser, and the heat storage heat exchanger is evaporator.CITATION LISTPatent Literature

[0003] Patent Literature 1: Japanese Laid-open Patent Publication No. 2016-17738SUMMARYTechnical Problem

[0004] However, in such an air conditioner, the amount of the liquid-phase refrigerant retained in the heat exchanger functioning as the condenser during the defrosting heating operation is larger than that during the heat storage heating operation. Specifically, even if the supercooling degree of the refrigerant on the condenser outlet side is the same, as the volume of the refrigerant flow path in the heat exchanger functioning as the condenser is larger, the region filled with the liquid-phase refrigerant in the refrigerant path of the heat exchanger is larger. In addition, the heat storage heat exchanger and the outdoor heat exchanger are formed such that a volume of the outdoor heat exchanger is larger than a volume of the heat storage heat exchanger due to a difference in a heat medium that exchanges heat with the refrigerant. In the heat storage heating operation, the heat storage heat exchanger functions as a condenser, and the outdoor heat exchanger functions as an evaporator. On the other hand, in the defrosting heating operation, the heat storage heat exchanger functions as an evaporator, and the outdoor heat exchanger functions as a condenser. At this time, the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger functioning as the condenser during the defrosting heating operation is larger than the amount of the liquid-phase refrigerant retained in the heat storage heat exchanger functioning as the condenser during the heat storage heating operation. Therefore, in a case where the refrigerant is charged based on the amount of refrigerant used during the heat storage heating operation, a large amount of the liquid-phase refrigerant retains in the outdoor heat exchanger during the defrosting heating operation, such that the flow rate of the refrigerant flowing into the indoor heat exchanger decreases and the heating capability deteriorates.

[0005] The disclosed technology has been made in view of such a problem, and an object of the disclosed technology is to provide an air conditioner that suppresses deterioration of indoor heating capability during a defrosting heating operation.Solution to Problem

[0006] According to an aspect of an embodiment, an air conditioner includes a compressor that compresses a refrigerant, an indoor heat exchanger that exchanges heat between indoor air and a refrigerant, an outdoor heat exchanger that exchanges heat between outside air and a refrigerant, a heat storage heat exchanger that exchanges heat between a heat storage material and a refrigerant, a plurality of switching valves that switches a circulation path of a refrigerant circuit in which a the refrigerant circulates between a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as a condenser and the outdoor heat exchanger function as an evaporator and a defrosting heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as a condenser and the heat storage heat exchanger function as an evaporator, a first flow path that connects the indoor heat exchanger and the outdoor heat exchanger, a branch portion that is provided in a middle of the first flow path, a second flow path that connects the heat storage heat exchanger and the branch portion, a first expansion valve that adjusts a flow rate of a refrigerant flowing through a portion of the first flow path between the indoor heat exchanger and the branch portion, and a second expansion valve that is provided between the indoor heat exchanger and the first expansion valve of the first flow path and decompresses aADVANTAGEOUS EFFECTS OF INVENTION

[0007] The air conditioner according to the disclosure can suppress deterioration of heating capability during defrosting heating operation.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a refrigerant circuit diagram illustrating an air conditioner according to an embodiment.

[0009] FIG. 2 is a block diagram illustrating the air conditioner.

[0010] FIG. 3 is a refrigerant circuit diagram illustrating the air conditioner according to the embodiment when normal heating operation is executed.

[0011] FIG. 4 is a refrigerant circuit diagram illustrating the air conditioner according to the embodiment when heat storage heating operation is executed.

[0012] FIG. 5 is a refrigerant circuit diagram illustrating the air conditioner according to the embodiment when defrosting heating operation is executed.DESCRIPTION OF EMBODIMENTS

[0013] Hereinafter, an air conditioner according to an embodiment disclosed in the present application will be described in detail with reference to the drawings. Note that the technology of the present disclosure is not limited by the following description. In addition, in the following description, the same components are denoted by the same reference numerals, and redundant description is omitted.Embodiments

[0014] FIG. 1 is a refrigerant circuit diagram illustrating an air conditioner 1 according to an embodiment. The air conditioner 1 of the embodiment includes an outdoor equipment 2 and an indoor equipment 3. The outdoor equipment 2 is installed outdoors. The indoor equipment 3 is installed in a room that is cooled and heated by the air conditioner 1. The air conditioner 1 further includes a refrigerant circuit 5. The refrigerant circuit 5 includes an indoor heat exchanger 6, an outdoor heat exchanger 7, and a heat storage heat exchanger 8, and includes a first refrigerant pipe 11 (first flow path) and a second refrigerant pipe 12 (second flow path). The indoor heat exchanger 6 is disposed inside the indoor equipment 3. The outdoor heat exchanger 7 is disposed inside the outdoor equipment 2 and is connected to the indoor heat exchanger 6 via the first refrigerant pipe 11. The in-pipe volume of the refrigerant flow path of the outdoor heat exchanger 7 is larger than the in-pipe volume of the refrigerant flow path of the indoor heat exchanger 6. The heat storage heat exchanger 8 is disposed inside the outdoor equipment 2 and is connected to a first branch portion 14 (branch portion) provided in the middle of the first refrigerant pipe 11 via the second refrigerant pipe 12. The in-pipe volume of the refrigerant flow path of the heat storage heat exchanger 8 is larger than the in-pipe volume of the refrigerant flow path of the indoor heat exchanger 6 and smaller than the in-pipe volume of the refrigerant flow path of the outdoor heat exchanger 7, The heat storage heat exchanger 8 includes a heat storage material 18.

[0015] The refrigerant circuit 5 further includes an outdoor equipment expansion valve 15 (first expansion valve), an indoor equipment expansion valve 16 (second expansion valve), and a heat storage heat exchange side expansion valve 17 (fourth expansion valve). The outdoor equipment expansion valve 15 is disposed inside the outdoor equipment 2 and is provided between the indoor heat exchanger 6 and the first branch portion 14 of the first refrigerant pipe 11. The outdoor equipment expansion valve 15 adjusts the flow rate of the refrigerant flowing through the portion between the indoor heat exchanger 6 and the first branch portion 14. The indoor equipment expansion valve 16 is disposed inside the indoor equipment 3 and is provided between the indoor heat exchanger 6 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11. At this time, in the air conditioner 1, as compared with other air conditioners in which both the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 are arranged in only one of the outdoor equipment 2 and the indoor equipment 3, the pressure loss can be reduced by allowing the refrigerant decompressed and reduced in pressure to flow through a flow path portion 19 between the indoor equipment expansion valve 16 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11. Therefore, the length of the portion can be increased, and the in-pipe volume of the refrigerant flow path of a flow path portion 19 can be increased. The heat storage heat exchange side expansion valve 17 is disposed inside the outdoor equipment 2 and is provided in the middle of the second refrigerant pipe 12.

[0016] The refrigerant circuit 5 further includes compressor 21, a plurality of switching valves 22, a third refrigerant pipe 23 (third flow path), a fourth refrigerant pipe 24 (fourth flow path), and a connection pipe side expansion valve 25 (fourth expansion valve), The compressor 21 is disposed inside the outdoor equipment 2 and includes a suction pipe 31 and a discharge pipe 32. The compressor 21 compresses a gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31, and discharges the compressed gas-phase refrigerant to the discharge pipe 32 to circulate the refrigerant in the refrigerant circuit 5.

[0017] The plurality of switching valves 22 is disposed inside the outdoor equipment 2, and include an indoor heat exchange side three-way valve 26, an outdoor heat exchange side three-way valve 27, and a heat storage heat exchange side three-way valve 28. The indoor heat exchange side three-way valve 26 is connected to the indoor heat exchanger 6, and is connected to the suction pipe 31 of the compressor 21. The indoor heat exchange side three-way valve 26 is further connected to the discharge pipe 32 of the compressor 21 via the third refrigerant pipe 23. The outdoor heat exchange side three-way valve 27 is connected to the outdoor heat exchanger 7, and is connected to the suction pipe 31 of the compressor 21. The outdoor heat exchange side three-way valve 27 is further connected to a second branch portion 33 provided in the middle of the third refrigerant pipe 23 via the fourth refrigerant pipe 24. The heat storage heat exchange side three-way valve 28 is connected to the heat storage heat exchanger 8, and is connected to the suction pipe 31 of the compressor 21. The heat storage heat exchange side three-way valve 28 is further connected to a third branch portion 34 provided in the middle of the fourth refrigerant pipe 24. The connection pipe side expansion valve 25 is disposed inside the outdoor equipment 2 and is provided between the second branch portion 33 and the third branch portion 34 of the fourth refrigerant pipe 24.

[0018] The plurality of switching valves 22 is switched to a normal heating position, a heat storage heating position, a defrosting heating position, and a cooling position. When the plurality of switching valves 22 is switched to the normal heating position, the discharge pipe 32 is connected to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, the connection pipe side expansion valve 25 is connected to the heat storage heat exchanger 8 via the heat storage heat exchange side three-way valve 28, and the outdoor heat exchanger 7 is connected to the suction pipe 31 via the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the heat storage heating position, the discharge pipe 32 is connected to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, the connection pipe side expansion valve 25 is connected to the heat storage heat exchanger 8 via the heat storage heat exchange side three-way valve 28, and the outdoor heat exchanger 7 is connected to the suction pipe 31 via the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the defrosting heating position, the discharge pipe 32 is connected to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, the connection pipe side expansion valve 25 is connected to the outdoor heat exchanger 7 via the outdoor heat exchange side three-way valve 27, and the heat storage heat exchanger 8 is connected to the suction pipe 31 via the heat storage heat exchange side three-way valve 28. When the plurality of switching valves 22 is switched to the cooling position, the connection pipe side expansion valve 25 is connected to the outdoor heat exchanger 7 via the outdoor heat exchange side three-way valve 27, and the indoor heat exchanger 6 is connected to the suction pipe 31 via the indoor heat exchange side three-way valve 26.

[0019] As illustrated in FIG. 2, the air conditioner 1 further includes a control device 41 (control unit). FIG. 2 is a block diagram illustrating the air conditioner 1.

[0020] The control device 41 is disposed inside the outdoor equipment 2 and includes a storage device 42 and a central processing unit (CPU) 43. The storage device 42 stores a computer program installed in the control device 41, and stores information used by the CPU 43. By executing a computer program installed in the control device 41, the CPU 43 controls the indoor heat exchange side three-way valve 26, the outdoor heat exchange side three-way valve 27, the heat storage heat exchange side three-way valve 28, the outdoor equipment expansion valve 15, the indoor equipment expansion valve 16, the heat storage heat exchange side expansion valve 17, and the connection pipe side expansion valve 25.

[0021] The operation executed by the air conditioner 1 includes a normal heating operation, a heat storage heating operation, a defrosting heating operation, and a cooling operation.[Normal Heating Operation]

[0022] The normal heating operation is executed, for example, when the user operates the air conditioner 1 to execute the normal heating operation. When the air conditioner 1 executes the normal heating operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the normal heating position. The control device 41 further controls the indoor equipment expansion valve 16 when the air conditioner 1 executes the normal heating operation. The opening degree of the indoor equipment expansion valve 16 is reduced by, for example, target discharge temperature control which is a known technique. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the outdoor equipment expansion valve 15 to fully open the opening degree of the outdoor equipment expansion valve 15. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the connection pipe side expansion valve 25 to reduce the opening degree of the connection pipe side expansion valve 25 to a predetermined opening degree. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to reduce the opening degree of the heat storage heat exchange side expansion valve 17 to a predetermined opening degree. At this time, the heat storage heat exchange side expansion valve 17 and the connection pipe side expansion valve 25 are controlled such that the decompression amount by which the heat storage heat exchange side expansion valve 17 decompresses the refrigerant is smaller than the decompression amount by which the connection pipe side expansion valve 25 decompresses the refrigerant, thereby suppressing excessive accumulation of the refrigerant in the second refrigerant pipe 12 including the heat storage heat exchanger 8.

[0023] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 flows into the indoor heat exchange side three-way valve 26 and also flows into the connection pipe side expansion valve 25.

[0024] The high-pressure gas-phase refrigerant that has flowed into the indoor heat exchange side three-way valve 26 flows into the indoor heat exchanger 6 when the plurality of switching valves 22 is switched to the normal heating position. The indoor heat exchanger 6 exchanges heat between the high-pressure gas-phase refrigerant flowing into the indoor heat exchanger 6 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air heated by the indoor heat exchanger 6 into the room to heat the room. The high-pressure gas-phase refrigerant subjected to heat exchange with air in a room by the indoor heat exchanger 6 is cooled and condensed by the indoor heat exchanger 6 to become a supercooled high-pressure liquid-phase refrigerant. That is, the indoor heat exchanger 6 functions as a condenser when the air conditioner 1 executes the normal heating operation.

[0025] The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor equipment expansion valve 16. Since the opening degree of the indoor equipment expansion valve 16 is reduced to a predetermined opening degree, a flow rate of the refrigerant flowing from the indoor heat exchanger 6 to the outdoor heat exchanger 7 is adjusted, and the high-pressure liquid-phase refrigerant flowing into the indoor equipment expansion valve 16 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the indoor equipment expansion valve 16 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the indoor equipment expansion valve 16 flows into the outdoor equipment expansion valve 15. The low-pressure gas-liquid two-phase refrigerant that has flowed into the outdoor equipment expansion valve 15 flows into the outdoor heat exchanger 7 as the low-pressure gas-liquid two-phase refrigerant by the opening degree of the outdoor equipment expansion valve 15 being fully opened. Therefore, as illustrated in FIG. 3, the flow path portion 19 between the indoor equipment expansion valve 16 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11 is filled with a gas-liquid two-phase refrigerant. FIG. 3 is a refrigerant circuit diagram illustrating the air conditioner 1 according to the embodiment when normal heating operation is executed. In FIG. 3, the flow path through which the liquid-phase refrigerant flows is indicated by a thick line.

[0026] Since the opening degree of the connection pipe side expansion valve 25 is reduced to a predetermined opening degree, the flow rate of the refrigerant flowing through the connection pipe side expansion valve 25 is adjusted such that the flow rate of the refrigerant flowing through the heat storage heat exchanger 8 becomes smaller than the flow rate of the refrigerant flowing through the indoor heat exchanger 6, and the high-pressure gas-phase refrigerant flowing into the connection pipe side expansion valve 25 is slightly decompressed. The high-pressure gas-phase refrigerant decompressed by the connection pipe side expansion valve 25 flows into the heat storage heat exchange side three-way valve 28. The high-pressure gas-phase refrigerant that has flowed into the heat storage heat exchange side three-way valve 28 flows into the heat storage heat exchanger 8 when the plurality of switching valves 22 is switched to the normal heating position. The heat storage heat exchanger 8 exchanges heat between the high-pressure gas-phase refrigerant flowing into the heat storage heat exchanger 8 and the heat storage material 18. The heat storage material 18 subjected to heat exchange with the high-pressure gas-phase refrigerant by the heat storage heat exchanger 8 is heated and stores heat. The high-pressure gas-phase refrigerant subjected to heat exchange with the heat storage material 18 by the heat storage heat exchanger 8 is cooled and condensed to become a supercooled high-pressure liquid-phase refrigerant. That is, the heat storage heat exchanger 8 functions as a condenser when the air conditioner 1 executes the normal heating operation.

[0027] The high-pressure liquid-phase refrigerant flowing out of the heat storage heat exchanger 8 flows into the heat storage heat exchange side expansion valve 17. The opening degree of the heat storage heat exchange side expansion valve 17 is reduced to a predetermined opening degree, such that the high-pressure liquid-phase refrigerant flowing in from the heat storage heat exchanger 8 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the heat storage heat exchange side expansion valve17 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the heat storage heat exchange side expansion valve 17 flows into the outdoor heat exchanger 7.

[0028] The outdoor heat exchanger 7 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the outdoor equipment expansion valve 15 and the heat storage heat exchange side expansion valve 17 and outside air. The low-pressure gas-liquid two-phase refrigerant is heated by the outdoor heat exchanger 7 to become a low-pressure gas-phase refrigerant. That is, the outdoor heat exchanger 7 functions as an evaporator when the air conditioner 1 executes the normal heating operation. The low-pressure gas-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the heating position, the low-pressure gas-phase refrigerant flowing into the outdoor heat exchange side three-way valve 27 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.

[0029] In the air conditioner 1, when the normal heating operation is executed, the refrigerant having a flow rate smaller than the flow rate of the refrigerant flowing through the indoor heat exchanger 6 flows through the heat storage heat exchanger 8, such that the amount of the refrigerant retained in the heat storage heat exchanger 8 can be reduced. The air conditioner 1 can suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 by reducing the amount of the refrigerant retained in the heat storage heat exchanger 8, and can suppress deterioration of heating capability.[Heat storage heating operation]

[0030] The heat storage heating operation is started, for example, when the normal heating operation is executed and a heat load due to heating is smaller than a predetermined threshold value. When the air conditioner 1 executes the heat storage heating operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the normal heat storage heating position. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the indoor equipment expansion valve 16 to fully open the opening degree of the indoor equipment expansion valve 16. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the outdoor equipment expansion valve 15 to reduce the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the connection pipe side expansion valve 25 to fully open the opening degree of the connection pipe side expansion valve 25. When the air conditioner 1 executes the heat storage heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to reduce the opening degree of the heat storage heat exchange side expansion valve 17 to a predetermined opening degree.

[0031] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 is supplied to the indoor heat exchange side three-way valve 26, and flows into the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant that has flowed into the indoor heat exchange side three-way valve 26 flows into the indoor heat exchanger 6 when the plurality of switching valves 22 is switched to the heat storage heating position.

[0032] The indoor heat exchanger 6 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the plurality of switching valves 22 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air heated by the indoor heat exchanger 6 into the room to heat the room. The high-pressure gas-phase refrigerant subjected to heat exchange by the indoor heat exchanger 6 is cooled to become a supercooled high-pressure liquid-phase refrigerant. That is, the indoor heat exchanger 6 functions as a condenser when the air conditioner 1 executes the heat storage heating operation.

[0033] The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor equipment expansion valve 16. The high-pressure liquid-phase refrigerant having flowed into the indoor equipment expansion valve 16 flows into the outdoor equipment expansion valve 15 as the high-pressure liquid-phase refrigerant without being decompressed by the indoor equipment expansion valve 16 since the opening degree of the indoor equipment expansion valve 16 is fully opened. The outdoor equipment expansion valve 15 reduces the pressure of the high-pressure liquid-phase refrigerant flowing in from the indoor equipment expansion valve 16 by reducing the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. The high-pressure liquid-phase refrigerant is decompressed by the outdoor equipment expansion valve 15 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the outdoor equipment expansion valve 15 flows into the outdoor heat exchanger 7. Therefore, as illustrated in FIG. 4, a space between the outdoor equipment expansion valve 15 of the first refrigerant pipe 11 and the outdoor heat exchanger 7 is filled with a low-pressure gas-liquid two-phase refrigerant having a low density, and the flow path portion 19 is filled with a high-pressure liquid-phase refrigerant having a high density. FIG. 4 is a refrigerant circuit diagram illustrating the air conditioner 1 according to the embodiment when heat storage heating operation is executed. In FIG. 4, the flow path through which the liquid-phase refrigerant flows is indicated by a

[0034] The high-pressure gas-phase refrigerant having flowed into the connection pipe side expansion valve 25 flows into the heat storage heat exchange side three-way valve 28 as the high-pressure gas-phase refrigerant without being decompressed since the opening degree of the connection pipe side expansion valve 25 is fully opened. The high-pressure gas-phase refrigerant that has flowed into the heat storage heat exchange side three-way valve 28 flows into the heat storage heat exchanger 8 when the plurality of switching valves 22 is switched to the heat storage heating position. The heat storage heat exchanger 8 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the heat storage heat exchange side three-way valve 28 and the heat storage material 18. The heat storage material 18 stores heat by being heated by the heat storage heat exchanger 8. The high-pressure gas-phase refrigerant subjected to heat exchange with the heat storage material 18 by the heat storage heat exchanger 8 is cooled and condensed by the heat storage heat exchanger 8 to become a supercooled high-pressure liquid-phase refrigerant. That is, the heat storage heat exchanger 8 functions as a condenser when the air conditioner 1 executes the heat storage heating operation. The high-pressure liquid-phase refrigerant flowing out of the heat storage heat exchanger 8 flows into the heat storage heat exchange side expansion valve 17. The opening degree of the heat storage heat exchange side expansion valve 17 is reduced to a predetermined opening degree, such that the high-pressure liquid-phase refrigerant flowing into the heat storage heat exchange side expansion valve 17 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the heat storage heat exchange side expansion valve 17 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the heat storage heat exchange side expansion valve 17 flows into the outdoor heat exchanger 7.

[0035] The outdoor heat exchanger 7 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the outdoor equipment expansion valve 15 and the heat storage heat exchange side expansion valve 17 and outside air. The low-pressure gas-liquid two-phase refrigerant is heated by the outdoor heat exchanger 7 to become a low-pressure gas-phase refrigerant. That is, the outdoor heat exchanger 7 functions as an evaporator when the air conditioner 1 executes the heat storage heating operation. The low-pressure gas-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the outdoor heat exchange side three-way valve 27. When the plurality of switching valves 22 is switched to the heat storage heating position, the low-pressure gas-phase refrigerant flowing into the outdoor heat exchange side three-way valve 27 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.

[0036] When the amount of the refrigerant flowing through the refrigerant circuit 5 is excessive, the area filled with the liquid-phase refrigerant in the refrigerant flow path inside the indoor heat exchanger 6 increases, such that the area using latent heat in the indoor heat exchanger 6 decreases, and thus the amount of heat exchange may decrease. That is, the heating capability of the air conditioner 1 may deteriorate. The air conditioner 1 can retain the liquid-phase refrigerant in the flow path portion 19 when the heat storage heating operation is executed. In addition, the air conditioner 1 can retain a large amount of liquid-phase refrigerant in the flow path portion 19 due to the large in-pipe volume of the refrigerant flow path of the flow path portion 19. When the heat storage heating operation is executed, the air conditioner 1 retains the liquid-phase refrigerant in the flow path portion 19, such that the amount of the refrigerant flowing through the indoor heat exchanger 6 can be suppressed from becoming excessive, and the heating capability can be suppressed from deteriorating,[Defrosting Heating Operation]

[0037] The defrosting heating operation is executed, for example, after the heat storage heating operation is performed, when heat is stored in the heat storage material 18, and when frost is formed on the outdoor heat exchanger 7. When the air conditioner 1 executes the defrosting heating operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the defrosting heating position. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the indoor equipment expansion valve 16 to reduce the opening degree of the indoor equipment expansion valve 16 to a predetermined opening degree. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the outdoor equipment expansion valve 15 to fully open the opening degree of the outdoor equipment expansion valve 15. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the connection pipe side expansion valve 25 to reduce the opening degree of the connection pipe side expansion valve 25 to a predetermined opening degree. When the air conditioner 1 executes the defrosting heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to reduce the opening degree of the heat storage heat exchange side expansion valve 17 to a predetermined opening degree.

[0038] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 is supplied to the indoor heat exchange side three-way valve 26, and flows into the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant that has flowed into the indoor heat exchange side three-way valve 26 flows into the indoor heat exchanger 6 when the plurality of switching valves 22 is switched to the defrosting heating position. The indoor heat exchanger 6 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the plurality of switching valves 22 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air heated by the indoor heat exchanger 6 into the room to heat the room. The high-pressure gas-phase refrigerant is cooled and condensed in the indoor heat exchanger 6 to become a high-pressure liquid-phase refrigerant in a supercooled state. That is, the indoor heat exchanger 6 functions as a condenser when the air conditioner 1 executes the defrosting heating operation.

[0039] The high-pressure liquid-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor equipment expansion valve 16. The indoor equipment expansion valve 16 reduces the pressure of the high-pressure liquid-phase refrigerant flowing in from the indoor heat exchanger 6 by reducing the opening degree of the indoor equipment expansion valve 16 to a predetermined opening degree. The high-pressure liquid-phase refrigerant is decompressed by the indoor equipment expansion valve 16 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the indoor equipment expansion valve 16 flows into the outdoor equipment expansion valve 15. The low-pressure gas-liquid two-phase refrigerant that has flowed into the outdoor equipment expansion valve 15 is not decompressed by the outdoor equipment expansion valve 15 because the outdoor equipment expansion valve 15 is fully opened, and flows into the heat storage heat exchange side expansion valve 17 as the low-pressure gas-liquid two-phase refrigerant. Therefore, as illustrated in FIG. 5, a space between the indoor heat exchanger 6 and the indoor equipment expansion valve 16 of the first refrigerant pipe 11 is filled with the high-pressure liquid-phase refrigerant, and the flow path portion 19 is filled with the low-pressure gas-liquid two-phase refrigerant. FIG. 5 is a refrigerant circuit diagram illustrating the air conditioner 1 according to the embodiment when defrosting heating operation is executed. In FIG. 5, the flow path through which the liquid-phase refrigerant flows is indicated by a thick line.

[0040] The connection pipe side expansion valve 25 slightly decompresses the high-pressure gas-phase refrigerant flowing into the connection pipe side expansion valve 25 by reducing the opening degree of the connection pipe side expansion valve 25 to a predetermined opening degree. The high-pressure gas-phase refrigerant decompressed by the connection pipe side expansion valve 25 flows into the outdoor heat exchange side three-way valve 27. The high-pressure gas-phase refrigerant that has flowed into the outdoor heat exchange side three-way valve 27 flows into the outdoor heat exchanger 7 when the plurality of switching valves 22 is switched to the defrosting heating position.

[0041] The outdoor heat exchanger 7 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the outdoor heat exchange side three-way valve 27 and frost formed on the outdoor heat exchanger 7. The frost formed on the outdoor heat exchanger 7 is heated and melted. At this time, the air conditioner 1 can cause the refrigerant having the temperature for defrosting to flow into the outdoor heat exchanger 7 by the amount of the refrigerant decompressed by the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant subjected to heat exchange with the frost formed by the outdoor heat exchanger 7 is cooled and condensed to become a supercooled high-pressure liquid-phase refrigerant. That is, the outdoor heat exchanger 7 functions as a condenser when the air conditioner 1 executes the defrosting heating operation. The outdoor heat exchanger 7 functions as a condenser to retain the liquid-phase refrigerant inside the outdoor heat exchanger 7. At this time, since the connection pipe side expansion valve 25 decompresses the refrigerant, the temperature of the refrigerant flowing through the outdoor heat exchanger 7 is low, and the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7 is small. The high-pressure liquid-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the heat storage heat exchange side expansion valve 17.

[0042] The opening degree of the heat storage heat exchange side expansion valve 17 is reduced to a predetermined opening degree, such that the high-pressure liquid-phase refrigerant flowing in from the indoor heat exchanger 6 and the outdoor heat exchanger 7 is decompressed. The high-pressure liquid-phase refrigerant is decompressed by the heat storage heat exchange side expansion valve 17 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the heat storage heat exchange side expansion valve 17 flows into the heat storage heat exchanger 8.

[0043] The heat storage heat exchanger 8 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the heat storage heat exchange side expansion valve 17 and the heat storage material 18. The low-pressure gas-liquid two-phase refrigerant heat-exchanged with the heat storage material 18 by the heat storage heat exchanger 8 is heated to become a low-pressure gas-phase refrigerant. That is, the heat storage heat exchanger 8 functions as an evaporator when the air conditioner 1 executes the defrosting heating operation. The low-pressure gas-phase refrigerant flowing out of the heat storage heat exchanger 8 flows into the heat storage heat exchange side three-way valve 28. When the plurality of switching valves 22 is switched to the defrosting heating position, the low-pressure gas-phase refrigerant flowing into the heat storage heat exchange side three-way valve 28 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.

[0044] In the air conditioner 1, the liquid-phase refrigerant stored in the flow path portion 19 during the heat storage heating operation is retained in the outdoor heat exchanger 7 when the defrosting heating operation is executed. As a result, it is possible to suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6, and can suppress deterioration of heating capability.[Cooling Operation]

[0045] The cooling operation is executed, for example, when the user operates the air conditioner 1 to execute the cooling operation. When the air conditioner 1 executes the cooling operation, the control device 41 controls the plurality of switching valves 22 to switch the plurality of switching valves 22 to the cooling position. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the connection pipe side expansion valve 25 to fully open the opening of the connection pipe side expansion valve 25. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to fully close the opening degree of the heat storage heat exchange side expansion valve 17. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the outdoor equipment expansion valve 15 to reduce the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. When the air conditioner 1 executes the cooling operation, the control device 41 further controls the indoor equipment expansion valve 16 to fully open the opening degree of the indoor equipment expansion valve 16.

[0046] The compressor 21 compresses the low-pressure gas-phase refrigerant flowing into the compressor 21 via the suction pipe 31. The low-pressure gas-phase refrigerant is compressed by the compressor 21 to become a high-pressure gas-phase refrigerant. The compressor 21 further discharges the high-pressure gas-phase refrigerant to the discharge pipe 32. The high-pressure gas-phase refrigerant discharged to the discharge pipe 32 flows into the connection pipe side expansion valve 25. The high-pressure gas-phase refrigerant having flowed into the connection pipe side expansion valve 25 flows into the outdoor heat exchange side three-way valve 27 as the high-pressure gas-phase refrigerant without being decompressed since the opening degree of the connection pipe side expansion valve 25 is fully opened. The high-pressure gas-phase refrigerant that has flowed into the outdoor heat exchange side three-way valve 27 flows into the outdoor heat exchanger 7 when the plurality of switching valves 22 is switched to the cooling position. The outdoor heat exchanger 7 exchanges heat between the high-pressure gas-phase refrigerant flowing in from the plurality of switching valves 22 and outside air. The high-pressure gas-phase refrigerant is cooled and condensed in the outdoor heat exchanger 7 to become a high-pressure liquid-phase refrigerant in a supercooled state. That is, the outdoor heat exchanger 7 functions as a condenser when the air conditioner 1 executes the cooling operation.

[0047] The high-pressure liquid-phase refrigerant flowing out of the outdoor heat exchanger 7 flows into the outdoor equipment expansion valve 15. The outdoor equipment expansion valve 15 reduces the pressure of the high-pressure liquid-phase refrigerant flowing in from the outdoor heat exchanger 7 by reducing the opening degree of the outdoor equipment expansion valve 15 to a predetermined opening degree. The high-pressure liquid-phase refrigerant is decompressed by the outdoor equipment expansion valve 15 to become a low-pressure gas-liquid two-phase refrigerant. The low-pressure gas-liquid two-phase refrigerant flowing out of the outdoor equipment expansion valve 15 flows into the indoor equipment expansion valve 16. The low-pressure gas-liquid two-phase refrigerant that has flowed into the indoor equipment expansion valve 16 is not decompressed by the indoor equipment expansion valve 16 because the indoor equipment expansion valve 16 is fully opened, and flows into the indoor heat exchanger 6 as the low-pressure gas-liquid two-phase refrigerant.

[0048] The indoor heat exchanger 6 exchanges heat between the low-pressure gas-liquid two-phase refrigerant flowing in from the indoor equipment expansion valve 16 and air in the room in which the indoor equipment 3 is installed. The indoor equipment 3 blows the air cooled by the indoor heat exchanger 6 into the room to cool the room. The low-pressure gas-liquid two-phase refrigerant is heated by the indoor heat exchanger 6 to become a low-pressure gas-phase refrigerant. That is, the indoor heat exchanger 6 functions as an evaporator when the air conditioner 1 executes the cooling operation. The low-pressure gas-phase refrigerant flowing out of the indoor heat exchanger 6 flows into the indoor heat exchange side three-way valve 26. When the plurality of switching valves 22 is switched to the cooling position, the low-pressure gas-phase refrigerant flowing into the indoor heat exchange side three-way valve 26 is supplied to the suction pipe 31 and sucked into the compressor 21 via the suction pipe 31.[Effects of Air Conditioner 1 According to Embodiment]

[0049] The air conditioner 1 according to the embodiment includes the refrigerant circuit 5 through which the refrigerant circulates. The refrigerant circuit 5 is provided with the compressor 21, the indoor heat exchanger 6, the outdoor heat exchanger 7, the heat storage heat exchanger 8, the plurality of switching valves 22, the first refrigerant pipe 11, the first branch portion 14, the second refrigerant pipe 12, the outdoor equipment expansion valve 15, and the indoor equipment expansion valve 16. The compressor 21 compresses a refrigerant. The indoor heat exchanger 6 exchanges heat between air in a room and a refrigerant. The outdoor heat exchanger 7 exchanges heat between outside air and a refrigerant. The heat storage heat exchanger 8 exchanges heat between the heat storage material 18 and a refrigerant. The plurality of switching valves 22 switches the circulation path of the refrigerant in the refrigerant circuit 5 between the heat storage heating operation and the defrosting heating operation. In the heat storage heating operation, the indoor heat exchanger 6 and the heat storage heat exchanger 8 are caused to function as condensers, and the outdoor heat exchanger 7 is caused to function as an evaporator. In the defrosting heating operation, the indoor heat exchanger 6 and the outdoor heat exchanger 7 are caused to function as condensers, and the heat storage heat exchanger 8 is caused to function as an evaporator. The first refrigerant pipe 11 connects the indoor heat exchanger 6 and the outdoor heat exchanger 7. The first branch portion 14 is provided in the middle of the first refrigerant pipe 11. The second refrigerant pipe 12 connects the heat storage heat exchanger 8 and the first branch portion 14. The outdoor equipment expansion valve 15 decompresses the refrigerant flowing through the portion of the first refrigerant pipe 11 between the indoor heat exchanger 6 and the first branch portion 14. The indoor equipment expansion valve 16 is provided between the indoor heat exchanger 6 and the outdoor equipment expansion valve 15 of the first refrigerant pipe 11, and decompresses the passing refrigerant.

[0050] In addition, the air conditioner 1 according to the embodiment further includes the control device 41 that controls the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 such that the liquid-phase refrigerant flows to the flow path portion 19 between the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 of the first refrigerant pipe 11 when the heat storage heating operation is executed. The control device 41 further controls the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 such that the gas-liquid two-phase refrigerant flows in the flow path portion 19 when the defrosting heating operation is executed.

[0051] The amount of the refrigerant flowing into the indoor heat exchanger 6 is reduced by the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7 when the defrosting heating operation is executed. When the amount of the refrigerant flowing into the indoor heat exchanger 6 is insufficient, the air conditioner 1 may have a deteriorated heating capability. The air conditioner 1 according to the embodiment can increase the amount of refrigerant flowing into the indoor heat exchanger 6 when the defrosting heating operation is executed by the amount of refrigerant retained in the flow path portion 19 when the heat storage heating operation is executed. Therefore, the air conditioner 1 according to the embodiment can suppress a decrease in the amount of the refrigerant flowing into the indoor heat exchanger 6 when the defrosting heating operation is executed, and can suppress deterioration of heating capability.

[0052] In addition, the air conditioner 1 according to the embodiment further includes the third refrigerant pipe 23, the fourth refrigerant pipe 24, and the connection pipe side expansion valve 25. The third refrigerant pipe 23 supplies the refrigerant compressed by the compressor 21 to the indoor heat exchanger 6 when the indoor heat exchanger 6 functions as a condenser. The fourth refrigerant pipe 24 supplies the compressed refrigerant to the outdoor heat exchanger 7 when the outdoor heat exchanger 7 functions as a condenser. The connection pipe side expansion valve 25 decompresses the refrigerant flowing through the fourth refrigerant pipe 24.

[0053] In addition, the control device 41 of the air conditioner 1 according to the embodiment controls the connection pipe side expansion valve 25 such that the pressure of the refrigerant flowing through the outdoor heat exchanger 7 becomes lower than the pressure of the refrigerant flowing through the indoor heat exchanger 6 when the defrosting heating operation is executed. The air conditioner 1 according to the embodiment can reduce the temperature of the refrigerant flowing through the outdoor heat exchanger 7 when the defrosting heating operation is executed, and can reduce the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7. The air conditioner 1 according to the embodiment reduces the amount of the liquid-phase refrigerant retained in the outdoor heat exchanger 7 when the defrosting heating operation is executed, thereby suppressing a decrease in the amount of the refrigerant flowing into the indoor heat exchanger 6 and suppressing deterioration of heating capability. In addition, the air conditioner 1 according to the embodiment can decompress the refrigerant flowing into the heat storage heat exchanger 8 from the outdoor heat exchanger 7 when the defrosting heating operation is

[0054] In addition, the air conditioner 1 according to the embodiment further includes the heat storage heat exchange side expansion valve 17 that decompresses the refrigerant flowing through the second refrigerant pipe 12. At this time, the air conditioner 1 according to the embodiment can decompress the refrigerant flowing from the heat storage heat exchanger 8 into the outdoor heat exchanger 7 when the heat storage heating operation is executed, and can reduce the amount of the refrigerant flowing into the heat storage heat exchanger 8 to be smaller than the amount of the refrigerant flowing into the indoor heat exchanger 6. The air conditioner 1 according to the embodiment can suppress shortage of the amount of the refrigerant flowing to the indoor heat exchanger 6, and can suppress deterioration of heating capability.

[0055] In addition, the plurality of switching valves 22 of the air conditioner 1 according to the embodiment further switches the path through which the refrigerant flows such that the normal heating operation in which the indoor heat exchanger 6 functions as a condenser and the outdoor heat exchanger 7 functions as an evaporator is executed. The control device 41 controls the connection pipe side expansion valve 25 and the 17 heat storage heat exchange side expansion valve 17 such that a decompression amount at which the heat storage heat exchange side expansion valve 17 decompresses the refrigerant is smaller than a decompression amount at which the connection pipe side expansion valve 25 decompresses the refrigerant when the normal heating operation is executed. The air conditioner 1 according to the embodiment can circulate the liquid-phase refrigerant retained in the heat storage heat exchanger 8 to the refrigerant circuit 5 to reduce the liquid-phase refrigerant retained in the heat storage heat exchanger 8 when the normal heating operation is executed. The air conditioner 1 according to the embodiment reduces the amount of the liquid-phase refrigerant retained in the heat storage heat exchanger 8 when the normal heating operation is executed, thereby making it possible to suppress a shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 and suppress deterioration of heating capability.

[0056] In addition, the outdoor equipment expansion valve 15 of the air conditioner 1 according to the embodiment is provided in the outdoor equipment 2 provided with the outdoor heat exchanger 7. The indoor equipment expansion valve 16 is provided in the indoor equipment 3 provided with the indoor heat exchanger 6. In the air conditioner 1 according to the embodiment, the length of the flow path portion 19 can be made longer and the in-pipe volume of the refrigerant flow path of the flow path portion 19 can be made larger as compared with other air conditioners in which both the outdoor equipment expansion valve 15 and the indoor equipment expansion valve 16 are arranged in only one of the outdoor equipment 2 and the indoor equipment 3. The air conditioner 1 according to the embodiment can increase the amount of the liquid-phase refrigerant retained in the flow path portion 19 when the heat storage heating operation is executed due to the large in-pipe volume of the refrigerant flow path of the flow path portion 19, In the air conditioner 1 according to the embodiment, the amount of the refrigerant retained in the flow path portion 19 when the heat storage heating operation is executed is large. Therefore, when the defrosting heating operation is executed, it possible to suppress a shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 and suppress deterioration of heating capability.

[0057] By the way, the air conditioner 1 according to the above-described embodiment causes the refrigerant to flow to the heat storage heat exchanger 8 when the normal heating operation is executed, but does not have to cause the refrigerant to flow to the heat storage heat exchanger 8. For example, when the air conditioner 1 executes the normal heating operation, the control device 41 controls the plurality of switching valves 22, connects the discharge pipe 32 to the indoor heat exchanger 6 via the indoor heat exchange side three-way valve 26, connects the outdoor heat exchanger 7 to the suction pipe 31 via the outdoor heat exchange side three-way valve 27, and connects the heat storage heat exchanger 8 to the suction pipe 31 via the heat storage heat exchange side three-way valve 28. When the air conditioner 1 executes the normal heating operation, the control device 41 further controls the heat storage heat exchange side expansion valve 17 to fully close the opening degree of the heat storage heat exchange side expansion valve 17. Even when the liquid-phase refrigerant is retained in the heat storage heat exchanger 8 before the normal heating operation is executed, the air conditioner 1 can supply the refrigerant to the suction pipe 31 and reduce the amount of the refrigerant retained in the heat storage heat exchanger 8. The air conditioner 1 can suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 by reducing the amount of the refrigerant retained in the heat storage heat exchanger 8, similarly to the air conditioner of the above-described embodiment, and can suppress deterioration of heating capability.

[0058] By the way, the air conditioner 1 according to the above-described embodiment is formed so as to execute the cooling operation, but may be formed so as not to execute the cooling operation. Even when the cooling operation is not executed, the air conditioner 1 can suppress shortage of the amount of the refrigerant flowing through the indoor heat exchanger 6 when the defrosting heating operation is executed, and can suppress deterioration of heating capability.

[0059] Although the embodiment has been described above, the embodiment is not limited by the contents described above. In addition, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, at least one of various omissions, substitutions, and changes of the components can be made without departing from the gist of the embodiments.REFERENCE SIGNS LIST1 AIR CONDITIONER

[0061] 2 OUTDOOR EQUIPMENT

[0062] 3 INDOOR EQUIPMENT

[0063] 5 REFRIGERANT CIRCUIT

[0064] 6 INDOOR HEAT EXCHANGER

[0065] 7 OUTDOOR HEAT EXCHANGER

[0066] 8 HEAT STORAGE HEAT EXCHANGER

[0067] 11 FIRST REFRIGERANT PIPE (FIRST FLOW PATH)

[0068] 12 SECOND REFRIGERANT PIPE (SECOND FLOW PATH)

[0069] 14 FIRST BRANCH PORTION (BRANCH PORTION)

[0070] 15 OUTDOOR EQUIPMENT EXPANSION VALVE (FIRST EXPANSION VALVE)

[0071] 16 INDOOR EQUIPMENT EXPANSION VALVE (SECOND EXPANSION VALVE)

[0072] 17 HEAT STORAGE HEAT EXCHANGE SIDE EXPANSION VALVE (FOURTH EXPANSION VALVE)

[0073] 18 HEAT STORAGE MATERIAL

[0074] 19 FLOW PATH PORTION

[0075] 21 COMPRESSOR

[0076] 22 PLURALITY OF SWITCHING VALVES

[0077] 23 THIRD REFRIGERANT PIPE (THIRD FLOW PATH)

[0078] 24 FOURTH REFRIGERANT PIPE (FOURTH FLOW PATH)

[0079] 25 CONNECTION PIPE SIDE EXPANSION VALVE (THIRD EXPANSION VALVE)

[0080] 41 CONTROL DEVICE (CONTROL UNIT)

Examples

embodiments

[0014]FIG. 1 is a refrigerant circuit diagram illustrating an air conditioner 1 according to an embodiment. The air conditioner 1 of the embodiment includes an outdoor equipment 2 and an indoor equipment 3. The outdoor equipment 2 is installed outdoors. The indoor equipment 3 is installed in a room that is cooled and heated by the air conditioner 1. The air conditioner 1 further includes a refrigerant circuit 5. The refrigerant circuit 5 includes an indoor heat exchanger 6, an outdoor heat exchanger 7, and a heat storage heat exchanger 8, and includes a first refrigerant pipe 11 (first flow path) and a second refrigerant pipe 12 (second flow path). The indoor heat exchanger 6 is disposed inside the indoor equipment 3. The outdoor heat exchanger 7 is disposed inside the outdoor equipment 2 and is connected to the indoor heat exchanger 6 via the first refrigerant pipe 11. The in-pipe volume of the refrigerant flow path of the outdoor heat exchanger 7 is larger than the in-pipe volume ...

Claims

1. An air conditioner comprising:a compressor that compresses a refrigerant;an indoor heat exchanger that exchanges heat between indoor air and a refrigerant;an outdoor heat exchanger that exchanges heat between outside air and a refrigerant;a heat storage heat exchanger that exchanges heat between a heat storage material and a refrigerant;a plurality of switching valves that switch a circulation path of a refrigerant circuit in which a refrigerant circulates between a heat storage heating operation in which the indoor heat exchanger and the heat storage heat exchanger function as a condenser and the outdoor heat exchanger function as an evaporator and a defrosting heating operation in which the indoor heat exchanger and the outdoor heat exchanger function as a condenser and the heat storage heat exchanger function as an evaporator;a first flow path that connects the indoor heat exchanger and the outdoor heat exchanger;a branch portion that is provided in the first flow path;a second flow path that connects the heat storage heat exchanger and the branch portion;a first expansion valve that adjusts a flow rate of a refrigerant flowing through a portion of the first flow path between the indoor heat exchanger and the branch portion; anda second expansion valve that is provided between the indoor heat exchanger and the first expansion valve of the first flow path and decompresses a refrigerant passing therethrough.

2. The air conditioner according to claim 1, further comprising:a control unit configured to control the first expansion valve and the second expansion valve such that a liquid-phase refrigerant flows in a flow path portion of the first flow path, the flow path portion being a flow path between the first expansion valve and the second expansion valve when the heat storage heating operation is executed, whereinthe control unit controls the first expansion valve and the second expansion valve such that a gas-liquid two-phase refrigerant flows in the flow path portion when the defrosting heating operation is executed.

3. The air conditioner according to claim 2, further comprising:a third flow path that supplies a refrigerant compressed by the compressor to the indoor heat exchanger when the indoor heat exchanger functions as a condenser;a fourth flow path that supplies the compressed refrigerant to the outdoor heat exchanger when the outdoor heat exchanger functions as a condenser; anda third expansion valve that decompresses a refrigerant flowing through the fourth flow path.

4. The air conditioner according to claim 3, whereinthe control unit controls the third expansion valve such that a pressure of a refrigerant flowing through the outdoor heat exchanger becomes lower than a pressure of a refrigerant flowing through the indoor heat exchanger when the defrosting heating operation is executed.

5. The air conditioner according to claim 4, further comprising:a fourth expansion valve that decompresses a refrigerant flowing through the second flow path.

6. The air conditioner according to claim 5, whereinthe plurality of switching valves further switch a path in which a refrigerant flows such that a normal heating operation in which the indoor heat exchanger functions as a condenser and the outdoor heat exchanger functions as an evaporator is executed, andthe control unit controls the third expansion valve and the fourth expansion valve such that an amount of a refrigerant flowing through the heat storage heat exchanger is reduced and such that a decompression amount at which the fourth expansion valve decompresses a refrigerant is larger than a decompression amount at which the third expansion valve decompresses a refrigerant when the normal heating operation is executed.

7. The air conditioner according to claim 1, whereinthe first expansion valve is provided in an outdoor equipment in which the outdoor heat exchanger is provided, andthe second expansion valve is provided in an indoor equipment in which the indoor heat exchanger is provided.

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