REFRIGERATION CYCLE DEVICE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No. PCT/JP2024/006544, filed on Feb. 22, 2024, which is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-026487 filed on Feb. 22, 2023; the entire contents of which are incorporated herein by reference.

FIELD

An embodiment of the present invention relates to a refrigeration cycle device.

BACKGROUND

A refrigeration cycle device capable of simultaneously performing cooling and heating operations in a plurality of indoor units is used. In a refrigeration cycle device, it is required to suppress generation of abnormal noise.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit diagram showing a refrigeration cycle device of an embodiment.

FIG. 2 is a cross-sectional view showing a third trunk pipe and a third branch pipe.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a refrigeration cycle device 1 of an embodiment will be described with reference to the drawings.

A refrigeration cycle device according to an embodiment includes an outdoor unit, a plurality of indoor units, a first pipe, a second pipe, a third pipe, a switching unit, and a control unit. The outdoor unit includes a compressor and an outdoor heat exchanger. A plurality of indoor units each include an indoor expansion valve and an indoor heat exchanger. The first pipe allows a refrigerant to flow between the outdoor heat exchanger and the indoor heat exchanger. The second pipe allows the refrigerant discharged from the compressor to flow into the indoor heat exchanger. The third pipe allows the refrigerant flowing out of the indoor heat exchanger to flow into the compressor. The switching unit switches connections of the second pipe and the third pipe with respect to the indoor heat exchanger. The control unit sets an upper-limit opening degree of the indoor expansion valve when a predetermined condition is satisfied in a state in which the indoor heat exchanger is connected to the third pipe in the switching unit.

According to the refrigeration cycle device according to the embodiment, in the above-described refrigeration cycle device, the upper-limit opening degree may be a value corresponding to at least one of capacity information and configuration information of the indoor unit.

According to the refrigeration cycle device according to the embodiment, in the above-described refrigeration cycle device, the predetermined condition may be a condition in which an instruction to set the upper-limit opening degree is input to the control unit.

According to the refrigeration cycle device according to the embodiment, in the above-described refrigeration cycle device, the predetermined condition may be a condition in which a predetermined time has not elapsed after the indoor unit started a cooling operation.

The above-described refrigeration cycle device according to the embodiment further includes a trunk pipe. Branch pipes corresponding to the plurality of indoor units and the third pipe may be connected to the trunk pipe. The indoor unit corresponding to the branch pipe positioned farthest from the third pipe in an axial direction of the trunk pipe may be defined as a first indoor unit. The control unit may set the upper-limit opening degree of the indoor expansion valve of the first indoor unit when the predetermined condition is satisfied in a state in which the indoor heat exchanger of the first indoor unit is connected to the third pipe in the switching unit.

FIG. 1 is a circuit diagram showing the refrigeration cycle device 1 of the embodiment. The refrigeration cycle device 1 includes an outdoor unit 11, a plurality of indoor units 10, and a pipe 30. The pipe 30 allows a refrigerant to flow between the outdoor unit 11 and the plurality of indoor units 10. The refrigeration cycle device 1 is a heat recovery type air conditioning system capable of simultaneously performing cooling and heating operations in the plurality of indoor units 10. In the example shown in FIG. 1, the refrigeration cycle device 1 includes four indoor units 10, namely a first indoor unit 10a, a second indoor unit 10b, a third indoor unit 10c, and a fourth indoor unit 10d.

The refrigeration cycle device 1 contains a refrigerant such as R410A, R32, R1123, R454B, R466A, or carbon dioxide (CO₂). The refrigerant circulates through the refrigeration cycle device 1 while changing its phase. In the present embodiment, a downstream side in a flow direction of the refrigerant may be simply referred to as a “downstream side”, and an upstream side in the flow direction of the refrigerant may be simply referred to as an “upstream side”.

The outdoor unit 11 includes a compressor 2, a check valve 3, a four-way valve 18, an outdoor heat exchanger 8, and an outdoor expansion valve 6b. The four-way valve 18 includes a first four-way valve 18a and a second four-way valve 18b. The first four-way valve 18a switches connections of the upstream side and the downstream side of the compressor 2 with respect to the outdoor heat exchanger 8. The second four-way valve 18b switches connections of the second pipe 32 and the third pipe 33 with respect to the compressor 2.

The plurality of indoor units 10 each have an indoor expansion valve 6a and an indoor heat exchanger 4. The indoor expansion valve 6a is, for example, an electronically controlled valve (Pulse Motor Valve: PMV). The outdoor expansion valve 6b and the indoor expansion valve 6a function as an expansion device 6.

The pipe 30 includes a first pipe 31, a second pipe 32, and a third pipe 33.

The first pipe (liquid pipe) 31 allows the refrigerant to flow between the outdoor heat exchanger 8 and the indoor heat exchanger 4. The outdoor expansion valve 6b is provided in the first pipe 31.

The second pipe (discharge gas pipe) 32 allows the refrigerant discharged from the compressor 2 to flow into the indoor heat exchanger 4.

The third pipe (suction gas pipe) 33 allows the refrigerant flowing out of the indoor heat exchanger 4 to flow into the compressor 2.

The refrigeration cycle device 1 includes a switching unit 40. The switching unit 40 switches connections of the second pipe 32 and the third pipe 33 with respect to the indoor heat exchangers 4 of the plurality of indoor units 10. The switching unit 40 includes branch pipes 61, 62, and 63, trunk pipes 51, 52, and 53, and on-off valves 42 and 43.

As the branch pipes 61, 62, and 63, the switching unit 40 has a first branch pipe 61, a second branch pipe 62, and a third branch pipe 63. The switching unit 40 has a plurality of first branch pipes 61, a plurality of second branch pipes 62, and a plurality of third branch pipes 63 corresponding to the plurality of indoor units 10. The first branch pipe 61 is connected to one of an inlet and an outlet of the indoor heat exchanger 4 via the indoor expansion valve 6a. The second branch pipe 62 and the third branch pipe 63 merge into a connection pipe 67. The connection pipe 67 is connected to the other of the inlet and the outlet of the indoor heat exchanger 4.

As the trunk pipes 51, 52, 53, the switching unit 40 has a first trunk pipe 51, a second trunk pipe 52, and a third trunk pipe 53. The first pipe 31 and the plurality of first branch pipes 61 are connected to the first trunk pipe 51. The second pipe 32 and the plurality of second branch pipes 62 are connected to the second trunk pipe 52. The third pipe 33 and the plurality of third branch pipes 63 are connected to the third trunk pipe 53. The plurality of branch pipes are connected to the first to third trunk pipes (header pipes), thereby forming first to third headers.

FIG. 2 is a cross-sectional view showing the third trunk pipe 53 and the third branch pipe 63. The third pipe 33 is connected to one end part of the third trunk pipe 53. The other end part of the third trunk pipe 53 is closed. The plurality of third branch pipes 63 are aligned in an axial direction of the third trunk pipe 53 and connected to intermediate portions of the third trunk pipe 53 in the axial direction. A distance from the third pipe 33 in the axial direction of the third trunk pipe 53 is greatest at the third branch pipe 63 corresponding to the first indoor unit 10a. Distal ends of the plurality of third branch pipes 63 protrude into the inside of the third trunk pipe 53. The first header of the first trunk pipe 51 and the second header of the second trunk pipe 52 shown in FIG. 1 are configured similarly to the third header of the third trunk pipe 53.

The switching unit 40 includes a second on-off valve 42 and a third on-off valve 43 which serve as the on-off valves 42 and 43, respectively. The second on-off valve 42 opens and closes the second branch pipe 62. The third on-off valve 43 opens and closes the third branch pipe 63. Only one of the second branch pipe 62 and the third on-off valve 43 is opened. When only the second branch pipe 62 is opened, the second pipe 32 is connected to the indoor heat exchanger 4 via the second trunk pipe 52. When only the third on-off valve 43 is opened, the third pipe 33 is connected to the indoor heat exchanger 4 via the third trunk pipe 53.

An outer strainer 35 and an inner strainer 65 are provided inside the switching unit 40. The outer strainer 35 is provided in the pipes 31, 32, and 33 on the side of the outdoor unit 11 of the trunk pipes 51, 52, and 53. The inner strainer 65 is provided in the first branch pipe 61 and the connection pipe 67 on the side of the indoor unit 10 of the trunk pipes 51, 52, and 53. The outer strainer 35 and the inner strainer 65 capture foreign matter contained in the refrigerant flowing through the pipes.

The refrigeration cycle device 1 includes a central processing unit (CPU), a memory, an auxiliary storage device, and the like. The CPU functions as a control unit 19 by executing a program stored in the memory and the auxiliary storage device. The control unit 19 controls an operation of each part of the refrigeration cycle device 1. The control unit 19 controls an operation of the four-way valve 18. The control unit 19 controls operations of the outdoor expansion valve 6b and the indoor expansion valve 6a. The control unit 19 controls operations of the on-off valves 42 and 43.

A case in which all the indoor units 10 perform a cooling operation (individual cooling) will be described.

The control unit 19 sets all the four-way valves 18 to the state shown in FIG. 1. The downstream side of the compressor 2 is connected to the outdoor heat exchanger 8. The control unit 19 opens the third on-off valves 43 and closes the second on-off valves 42 corresponding to all the indoor units 10. The indoor heat exchangers 4 of all the indoor units 10 are connected to the third pipe 33.

The compressor 2 compresses a low-pressure gaseous refrigerant suctioned into the inside into a high-temperature and high-pressure gaseous refrigerant. The refrigerant discharged from the compressor 2 flows into the first four-way valve 18a via an oil separator 2b and the check valve 3. The refrigerant flows into the outdoor heat exchanger 8 of the outdoor unit 11 from the first four-way valve 18a.

The outdoor heat exchanger 8 functions as a condenser (heat radiator). The condenser dissipates heat from a high-temperature and high-pressure gaseous refrigerant flowing in from the compressor 2 to convert the high-temperature and high-pressure gaseous refrigerant into a high-pressure liquid refrigerant.

The refrigerant flowing out of the outdoor heat exchanger 8 passes through the first pipe 31 and flows into the outdoor expansion valve 6b and the indoor expansion valves 6a of all the indoor units 10. The outdoor expansion valve 6b and the indoor expansion valve 6a reduce a pressure of the high-pressure liquid refrigerant supplied from the outdoor heat exchanger 8 and convert the high-pressure liquid refrigerant into a low-temperature and low-pressure gas-liquid two-phase refrigerant. The refrigerant flowing out of the indoor expansion valve 6a flows into the indoor heat exchanger 4.

The indoor heat exchanger 4 functions as an evaporator (heat absorber). The evaporator converts the gas-liquid two-phase refrigerant flowing in from the indoor expansion valve 6a into a low-pressure gaseous refrigerant. The refrigerant flowing out from the indoor heat exchangers 4 of all the indoor units 10 passes through the third pipe 33 and flows into the compressor 2 via an accumulator (gas-liquid separator) 2a.

A case in which all the indoor units 10 perform a heating operation (single heating) will be described.

The control unit 19 switches all the four-way valves 18 from the state shown in FIG. 1 to a switched state. Therefore, the upstream side of the compressor 2 is connected to the outdoor heat exchanger 8. The second pipe 32 is connected to the downstream side of the compressor 2. The control unit 19 opens the second on-off valves 42 and closes the third on-off valves 43 corresponding to all the indoor units 10. The indoor heat exchangers 4 of all the indoor units 10 are connected to the second pipe 32.

The refrigerant discharged from the compressor 2 passes through the second four-way valve 18b and the second pipe 32, and flows into the indoor heat exchangers 4 of all the indoor units 10. The indoor heat exchanger 4 functions as a condenser (heat radiator). The refrigerant flowing out of the indoor heat exchangers 4 of all the indoor units 10 passes through the indoor expansion valve 6a, the first pipe 31, and the outdoor expansion valve 6b, and flows into the outdoor heat exchanger 8. The outdoor heat exchanger 8 functions as an evaporator (heat absorber). The refrigerant flowing out of the outdoor heat exchanger 8 passes through the first four-way valve 18a and flows into the compressor 2.

A case in which, among the plurality of indoor units 10, a heating operation of the first indoor unit 10a and cooling operations of the other indoor units 10b to 10d are simultaneously performed will be described. The refrigeration cycle device 1 performs a simultaneous operation of cooling and heating (simultaneous cooling), with cooling as a main operation.

The control unit 19 sets a state of the first four-way valve 18a to the state shown in FIG. 1. The downstream side of the compressor 2 is connected to the outdoor heat exchanger 8. The control unit 19 switches the second four-way valve 18b from the state shown in FIG. 1. The second pipe 32 is connected to the downstream side of the compressor 2.

The control unit 19 opens the second on-off valve 42 and closes the third on-off valve 43 corresponding to the first indoor unit 10a. The indoor heat exchanger 4 of the first indoor unit 10a is connected to the second pipe 32. The control unit 19 opens the third on-off valves 43 and closes the second on-off valves 42 corresponding to the other indoor units 10b, 10c, and 10d. The indoor heat exchangers 4 of the other indoor units 10b, 10c, and 10d are connected to the third pipe 33.

The refrigerant discharged from the compressor 2 passes through the second four-way valve 18b and the second pipe 32, and flows into the first indoor unit 10a. The indoor heat exchanger 4 of the first indoor unit 10a functions as a condenser (heat radiator). The refrigerant flowing out of the indoor heat exchanger 4 flows into the first trunk pipe 51.

The refrigerant discharged from the compressor 2 passes through the first four-way valve 18a, the outdoor heat exchanger 8, and the first pipe 31, and flows into the first trunk pipe 51. The refrigerant in the first trunk pipe 51 flows into the other indoor units 10b, 10c, and 10d. The indoor heat exchangers 4 of the other indoor units 10b, 10c, and 10d function as evaporators (heat absorbers). The refrigerant flowing out of these indoor heat exchangers 4 passes through the third pipe 33 and flows into the compressor 2.

A case in which, among the plurality of indoor units 10, a cooling operation of the first indoor unit 10a and heating operations of the other indoor units 10b to 10d are simultaneously performed will be described. The refrigeration cycle device 1 performs a simultaneous operation of cooling and heating (simultaneous heating), with heating as a main operation.

The control unit 19 switches the first four-way valve 18a from the state shown in FIG. 1 to a switched state. The upstream side of the compressor 2 is connected to the outdoor heat exchanger 8. The control unit 19 sets the second four-way valve 18b to the state shown in FIG. 1.

The control unit 19 opens the third on-off valve 43 and closes the second on-off valve 42 corresponding to the first indoor unit 10a. The indoor heat exchanger 4 of the first indoor unit 10a is connected to the third pipe 33. The control unit 19 opens the second on-off valves 42 and closes the third on-off valves 43 corresponding to the other indoor units 10b, 10c, and 10d. The indoor heat exchangers 4 of the other indoor units 10b, 10c, and 10d are connected to the second pipe 32.

The refrigerant discharged from the compressor 2 passes through the second four-way valve 18b and the second pipe 32, and flows into the other indoor units 10b, 10c, and 10d. The indoor heat exchangers 4 of the other indoor units 10b, 10c, and 10d function as condensers (heat radiators). The refrigerant flowing out of these indoor heat exchangers 4 flows into the first trunk pipe 51. Some of the refrigerant in the first trunk pipe 51 passes through the first pipe 31 and the outdoor heat exchanger 8, and flows into the compressor 2.

A remaining portion of the refrigerant in the first trunk pipe 51 flows into the first indoor unit 10a. The indoor heat exchanger 4 of the first indoor unit 10a functions as an evaporator (heat absorber). The refrigerant flowing out of the indoor heat exchanger 4 passes through the third pipe 33 and flows into the compressor 2.

An abnormal noise generated during the cooling operation of the indoor unit 10 will be described.

When the indoor unit 10 performs the cooling operation, the indoor heat exchanger 4 functions as an evaporator (heat absorber). The indoor heat exchanger 4 changes the gas-liquid two-phase refrigerant into a low-pressure gaseous refrigerant. When the indoor unit 10 performs the cooling operation, the third on-off valve 43 is opened and the second on-off valve 42 is closed. The indoor heat exchanger 4 is connected to the third pipe 33. The refrigerant flowing out of the indoor heat exchanger 4 passes through the connection pipe 67, the third branch pipe 63, the third trunk pipe 53, and the third pipe 33, and flows into the compressor 2.

There are cases in which the gas-liquid two-phase refrigerant flows out from the indoor heat exchanger 4. If the liquid refrigerant contained in the gas-liquid two-phase refrigerant flows into the compressor 2, the compressor 2 may fail. The control unit 19 sets a target value of a degree of superheat of the refrigerant flowing out of the indoor heat exchanger 4. The control unit 19 controls an opening degree of the indoor expansion valve 6a so that the degree of superheat exceeds the target value. When the degree of superheat exceeds the target value, an outflow of the liquid refrigerant from the indoor heat exchanger 4 is suppressed.

When the operation of the indoor unit 10 starts or stops, when a rotation speed of the compressor 2 changes, or the like, the degree of superheat may fall below the target value. In this case, the gas-liquid two-phase refrigerant containing the liquid refrigerant flows out from the indoor heat exchanger 4. Abnormal noise is generated in a process in which the liquid refrigerant flows through the connection pipe 67, the third branch pipe 63, the third trunk pipe 53, and the third pipe 33. The abnormal noise is a keen sound of approximately 4 to 7 Hz. The abnormal noise is generated in the inner strainer 65 provided in the connection pipe 67, the third on-off valve 43 provided in the third branch pipe 63, inside the third trunk pipe 53, the outer strainer 35 provided in the third pipe 33, or the like. As shown in FIG. 2, a distal end of the third branch pipe 63 protrudes into the inside of the third trunk pipe 53. When the liquid refrigerant flows inside the third trunk pipe 53, if a vortex is generated at the distal end of the third branch pipe 63, a risk of abnormal noise generation increases.

When a predetermined condition is satisfied, the control unit 19 performs a refrigerant flow rate suppression operation of the indoor unit 10 performing the cooling operation. As the refrigerant flow rate suppression operation, the control unit 19 sets an upper-limit opening degree (an upper-limit value of the opening degree) of the indoor expansion valve 6a of the indoor unit 10 performing the cooling operation. The upper-limit opening degree is a predetermined constant value according to the refrigeration cycle device 1. The upper-limit opening degree is an opening degree of the indoor expansion valve 6a at which the degree of superheat becomes greater than the target value when the indoor unit 10 operates under a rated cooling condition. For example, if the indoor expansion valve 6a has an opening control range of 0 to 500 pls, the upper-limit opening degree is set to 150 pls.

The control unit 19 controls the opening degree of the indoor expansion valve 6a to be lower than or equal to the upper-limit opening degree. A flow rate of the refrigerant flowing through the indoor heat exchanger 4 is restricted. Since heat exchange in the indoor heat exchanger 4 is performed on a small amount of refrigerant, a temperature of the refrigerant is likely to increase. The degree of superheat of the refrigerant flowing out of the indoor heat exchanger 4 exceeds the target value. An outflow of the liquid refrigerant from the indoor heat exchanger 4 is suppressed. Generation of abnormal noise associated with the flow of the liquid refrigerant is suppressed.

The upper-limit opening degree is a value corresponding to at least one of capacity information and configuration information of the indoor unit 10. Generally, a refrigerant circulation amount varies depending on the capacity and configuration of the indoor unit 10. The upper-limit opening degree is set to achieve a balance between performance of the indoor unit 10 and suppression of abnormal noise.

The upper-limit opening degree is set to a larger value as the capacity of the indoor unit 10 increases. The upper-limit opening degree is set to a smaller value as the capacity of the indoor unit 10 decreases. The capacity of the indoor unit 10 is expressed in horsepower (HP). For example, when the capacity of the indoor unit 10 is 6 HP, the upper-limit opening degree is set to 200 pls. When the capacity of the indoor unit 10 is 1 HP, the upper-limit opening degree is set to 100 pls.

An amount of heat exchange of the indoor heat exchanger 4 varies depending on a configuration of the indoor unit 10. The upper-limit opening degree is set to a larger value as the amount of heat exchange of the indoor heat exchanger 4 increases. The upper-limit opening degree is set to a smaller value as the amount of heat exchange of the indoor heat exchanger 4 decreases. For example, when the configuration of the indoor unit 10 is of a ceiling cassette type with four-way outlet, an amount of heat exchange of the indoor heat exchanger 4 is large, and thus the upper-limit opening degree is set to 170 pls. When the configuration of the indoor unit 10 is of a duct type, an amount of heat exchange of the indoor heat exchanger 4 is small, and thus the upper-limit opening degree is set to 130 pls.

As described above, when a predetermined condition is satisfied, the control unit 19 sets the upper-limit opening degree of the indoor expansion valve 6a.

One of the predetermined conditions is a condition in which an instruction to set the upper-limit opening degree is input to the control unit 19. An operator (such as a maintenance worker or a user) of the refrigeration cycle device 1 inputs an instruction to set the upper-limit opening degree when abnormal noise is heard. The operator inputs an instruction to set the upper-limit opening degree from a control board of the outdoor unit 11, a remote operation device (remote controller) of the indoor unit 10, or the like. When an instruction to set the upper-limit opening degree is input, the control unit 19 sets the upper-limit opening degree of the indoor expansion valve 6a. Generation of abnormal noise during the cooling operation of the indoor unit 10 is suppressed.

One of the predetermined conditions is a condition in which the predetermined time has not elapsed since the indoor unit 10 started the cooling operation. While the operation of the indoor unit 10 is stopped, since a temperature of the refrigerant decreases, the liquid refrigerant remains in the indoor unit 10. When the operation of the indoor unit 10 starts, the liquid refrigerant that has remained flows, and abnormal noise is likely to be generated. The control unit 19 sets the upper-limit opening degree of the indoor expansion valve 6a until the predetermined time elapses after the indoor unit 10 has started the cooling operation. Generation of abnormal noise at the start of the cooling operation of the indoor unit 10 is suppressed.

A first upper-limit opening degree set at the start of cooling operation of the indoor unit is the same as a second upper-limit opening degree set on the basis of an instruction from the operator. The first upper-limit opening degree may be smaller than the second upper-limit opening degree. Generation of abnormal noise is satisfactorily suppressed.

The predetermined time during which the first upper-limit opening degree is set is predetermined according to a magnitude of the first upper-limit opening degree. The predetermined time is a sufficient time for the liquid refrigerant that has remained to vaporize.

A timing at which the control unit 19 starts setting the first upper-limit opening degree may be a time point at which the compressor 2 starts an operation instead of a time point at which the indoor unit 10 starts the cooling operation.

As shown in FIG. 2, the switching unit 40 includes the third trunk pipe 53. The third pipe 33 and third branch pipes 63 corresponding to the plurality of indoor units 10 are connected to the third trunk pipe 53. The first indoor unit 10a is the indoor unit 10 corresponding to the third branch pipe 63 positioned farthest from the third pipe 33 in the axial direction of the third trunk pipe 53. When the predetermined condition is satisfied, the control unit 19 sets the upper-limit opening degree of the indoor expansion valve 6a of the first indoor unit 10a performing the cooling operation.

The third branch pipe 63 corresponding to the first indoor unit 10a is referred to as an “end part third branch pipe 63”, and the third branch pipes 63 corresponding to the other indoor units 10b, 10c, and 10d are referred to as “the other third branch pipes 63”. When the first indoor unit 10a performs the cooling operation, the refrigerant flows into the third trunk pipe 53 from the end part third branch pipe 63. Inside the third trunk pipe 53, between the end part third branch pipe 63 and the third pipe 33, distal ends of the other third branch pipes 63 protrude. The liquid refrigerant having flowed into the third trunk pipe 53 from the end part third branch pipe 63 passes by the distal ends of all of the other third branch pipes 63. If a vortex is generated at the distal ends of the other third branch pipes 63, a risk of abnormal noise generation increases. The liquid refrigerant having flowed into the third trunk pipe 53 from the end part third branch pipe 63 has more opportunities to pass by the distal ends of the third branch pipes 63 than the refrigerant having flowed into the third trunk pipe 53 from the other third branch pipes 63. When the first indoor unit 10a performs cooling operation, there is a higher risk of abnormal noise generation compared to when the other indoor units 10b, 10c, and 10d perform a cooling operation.

The control unit 19 sets the upper-limit opening degree of the indoor expansion valve 6a when at least the first indoor unit 10a performs the cooling operation. An inflow of the liquid refrigerant from the end part third branch pipe 63 into the third trunk pipe 53 is suppressed. Generation of abnormal noise is satisfactorily suppressed. It is desirable for the control unit 19 to set the upper-limit opening degree of the indoor expansion valve 6a even when the other indoor units 10b, 10c, and 10d perform the cooling operation. Generation of abnormal noise is satisfactorily suppressed.

As described above in detail, the refrigeration cycle device 1 of the embodiment includes the outdoor unit 11, the plurality of indoor units 10, the first pipe 31, the second pipe 32, the third pipe 33, the switching unit 40, and the control unit 19. The outdoor unit 11 includes the compressor 2 and the outdoor heat exchanger 8. The plurality of indoor units 10 each include the indoor expansion valve 6a and the indoor heat exchanger 4. The first pipe 31 allows the refrigerant to flow between the outdoor heat exchanger 8 and the indoor heat exchanger 4. The second pipe 32 allows the refrigerant discharged from the compressor 2 to flow into the indoor heat exchanger 4. The third pipe 33 allows the refrigerant flowing out of the indoor heat exchanger 4 to flow into the compressor 2. The switching unit 40 switches connections of the second pipe 32 and the third pipe 33 with respect to the indoor heat exchanger 4. The control unit 19 sets the upper-limit opening degree of the indoor expansion valve 6a when the predetermined condition is satisfied in a state in which the indoor heat exchanger 4 is connected to the third pipe 33 in the switching unit 40.

When the upper-limit opening degree of the indoor expansion valve 6a is set, a flow rate of the refrigerant flowing through the indoor heat exchanger 4 is restricted. Since heat exchange in the indoor heat exchanger 4 is performed on a small amount of refrigerant, a temperature of the refrigerant is likely to increase. A degree of superheat of the refrigerant flowing out of the indoor heat exchanger 4 exceeds a target value. An outflow of the liquid refrigerant from the indoor heat exchanger 4 is suppressed. Generation of abnormal noise associated with the flow of the liquid refrigerant is suppressed.

According to at least one of the embodiments described above, the control unit 19 that sets the upper-limit opening degree of the indoor expansion valve 6a of the indoor unit 10 that performs the cooling operation is provided. Therefore, it is possible to suppress generation of abnormal noise.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.