Refrigeration cycle device, control device, control method, and control program

Abstract

A refrigeration cycle device (100) comprises: a first refrigerant circuit (Hs1), which is provided with a compressor (C1), a first heat exchanger (Ha1), a pressure-reducing device (Ea1), and a first four-way valve (Fw1), and which circulates a first refrigerant; a second refrigerant circuit (Ws1), which is provided with a pump (Pm1) and a second heat exchanger (Hc1), and which circulates a second refrigerant; a heat exchanger (Hb1) that exchanges heat between the first refrigerant and the second refrigerant; and a control device (10). The control device controls the first four-way valve to switch the direction in which the first refrigerant flows between a direction in which the first refrigerant flows from the compressor into the first heat exchanger and a direction in which the first refrigerant flows from the compressor into the pressure-reducing device. This refrigeration cycle device comprises a switching device (Fw2) that switches the direction of flow so that the direction in which the first refrigerant flows and the direction in which a second refrigerant flows are the opposite of each other. When the direction in which the first refrigerant flows is switched by controlling the first four-way valve, the control device controls the switching device to switch the direction of refrigerant flow.

Description

Refrigeration cycle device, control device, control method, and control program

[0001] The present disclosure relates to a refrigeration cycle device, a control device, a control method, and a control program.

[0002] Conventionally, there is a so-called water-type refrigeration cycle device having a refrigeration cycle system that circulates a refrigerant using a compressor and a heat medium cycle circuit that circulates a heat medium such as antifreeze or water. In such a water-type refrigeration cycle device, heat exchange is performed between the refrigerant in the refrigerant circuit and the heat medium in the heat medium cycle circuit in a heat exchanger.

[0003] Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2020-159585) describes a refrigeration cycle device in which a cross flow is generated in a heat exchanger that exchanges heat between a refrigerant and a heat medium by switching a four-way valve arranged in a heat medium cycle circuit based on a detection value of a temperature detection unit installed in a pipe of the refrigeration cycle system.

[0004] Japanese Unexamined Patent Application Publication No. 2020-159585

[0005] In such a water-type refrigeration cycle device, if heat exchange is performed on the fluid in a non-cross flow state, the efficiency of heat exchange between the heat medium and the refrigerant will decrease. Therefore, after the circulation direction of the refrigerant circuit including the compressor is switched, it is desired that the circulation direction of the refrigerant circuit that circulates the heat medium be switched early.

[0006] The present disclosure has been made to solve such problems, and an object thereof is to provide a refrigeration cycle device capable of early switching the circulation direction of a refrigerant circuit that circulates a heat medium after the circulation direction of a refrigerant circuit including a compressor is switched.

[0007] The refrigeration cycle apparatus in this disclosure comprises a first refrigerant circuit configured to circulate a first refrigerant, comprising a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve; a second refrigerant circuit configured to circulate a second refrigerant, comprising a pump and a second heat exchanger; a heat exchanger for heat exchange between the first refrigerant and the second refrigerant; and a control device for controlling the first refrigerant circuit and the second refrigerant circuit. The control device can control the first four-way valve to switch the direction in which the first refrigerant flows between the direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and the direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device. The refrigeration cycle apparatus further comprises at least one switching device for switching the direction in which the first refrigerant or the second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite in the heat exchanger. When the direction in which the first refrigerant flows can be switched by controlling the first four-way valve, the control device controls at least one switching device to switch the direction in which the first refrigerant or the second refrigerant flows.

[0008] The control device in this disclosure is a control device for controlling a refrigeration cycle system comprising a first refrigerant circuit configured to circulate a first refrigerant, a second refrigerant circuit configured to circulate a second refrigerant, and a heat exchanger for heat exchange between the first and second refrigerants. The first refrigerant circuit comprises a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve. The second refrigerant circuit comprises a pump and a second heat exchanger. The control device can control the first four-way valve to switch the direction in which the first refrigerant flows between a direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and a direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device. The refrigeration cycle system further comprises at least one switching device for switching the direction in which the first or second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite each other in the heat exchanger. When the control device controls the first four-way valve to switch the direction in which the first refrigerant flows, it controls at least one switching device to switch the direction in which the first or second refrigerant flows.

[0009] The control method in this disclosure is a control method used in a control device for controlling a refrigeration cycle apparatus comprising a first refrigerant circuit configured to circulate a first refrigerant, a second refrigerant circuit configured to circulate a second refrigerant, and a heat exchanger for heat exchange between the first and second refrigerants. The first refrigerant circuit comprises a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve. The second refrigerant circuit comprises a pump and a second heat exchanger. The control device can control the first four-way valve to switch the direction in which the first refrigerant flows between a direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and a direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device. The refrigeration cycle apparatus further comprises at least one switching device for switching the direction in which the first or second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite each other in the heat exchanger. The control method includes, as a process to be executed by the control device, the steps of controlling the first four-way valve to switch the direction in which the first refrigerant flows, and controlling at least one switching device to switch the direction in which the first or second refrigerant flows.

[0010] The control program in this disclosure is a control program used in a control device for a refrigeration cycle apparatus comprising a first refrigerant circuit configured to circulate a first refrigerant, a second refrigerant circuit configured to circulate a second refrigerant, and a heat exchanger for heat exchange between the first and second refrigerants. The first refrigerant circuit comprises a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve. The second refrigerant circuit comprises a pump and a second heat exchanger. The control device can control the first four-way valve to switch the direction in which the first refrigerant flows between the direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and the direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device. The refrigeration cycle apparatus further comprises at least one switching device for switching the direction in which the first or second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite each other in the heat exchanger. The control program causes the control device to perform the steps of controlling the first four-way valve to switch the direction in which the first refrigerant flows, and controlling at least one switching device to switch the direction in which the first or second refrigerant flows.

[0011] According to this disclosure, after the circulation direction of the refrigerant circuit equipped with a compressor has been switched, the circulation direction of the refrigerant circuit that circulates the heat transfer medium can be switched early.

[0012] This is a diagram illustrating the refrigeration cycle device in Embodiment 1. This is a flowchart showing the process when switching between the cooling state and the heating state in Embodiment 1. This is a diagram illustrating the refrigeration cycle device when it is in the heating state. This is a diagram illustrating the refrigeration cycle device in Embodiment 2. This is a flowchart showing the process when switching between the cooling state and the heating state in Embodiment 2. This is a diagram showing the state of the refrigeration cycle device at the end of step S204. This is a diagram showing the state of the refrigeration cycle device at the end of step S207. This is a diagram illustrating the refrigeration cycle device in Embodiment 3. This is a flowchart showing the process when switching from the heating state to the cooling state in Embodiment 3. This is a diagram showing the state of the refrigeration cycle device at the end of step S306. This is a flowchart showing the process when switching from the cooling state to the heating state in Embodiment 3. This is a diagram illustrating the refrigeration cycle device in Embodiment 4. This is an external view of the housing when it is in the heating state in Embodiment 4. This is a flowchart showing the process when switching from the heating state to the cooling state in Embodiment 4. This is a diagram showing the state of the refrigeration cycle device at the end of step S406. This is an external view of the housing when it is in the cooling state in Embodiment 4. This is a flowchart showing the process when switching from the cooling state to the heating state in Embodiment 4. This is a diagram illustrating the refrigeration cycle device in the heating state in Embodiment 5. This is a flowchart illustrating the process of switching between the cooling state and the heating state in Embodiment 5. This is a diagram illustrating the refrigeration cycle device in the cooling state in Embodiment 5.

[0013] The embodiments of the technical concept relating to this disclosure will be described below with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated.

[0014] Embodiment 1. <Configuration of the Air Conditioning System> Figure 1 is a diagram illustrating the refrigeration cycle device 100 in Embodiment 1. The refrigeration cycle device 100 is a system for adjusting the air temperature in the space where the load-side unit Ws1 is located. Figure 1 shows the refrigeration cycle device 100 in the cooling state. In the refrigeration cycle device 100, the refrigeration cycle device 100 is switched between a cooling state and a heating state by switching the four-way valve Fw1.

[0015] The refrigeration cycle device 100 comprises a load-side unit Ws1, a heat source-side unit Hs1, a heat exchanger Hb1, and a control device 10. The load-side unit Ws1 includes a pump Pm1, a four-way valve Fw2, and a heat exchanger Hc1, which are arranged on a circulation channel Cr1. In the load-side unit Ws1, a heat transfer medium circulates within the circulation channel Cr1. The heat transfer medium may be water or antifreeze, etc.

[0016] The heat transfer medium circulating in the circulation channel Cr1 is cooled or heated in the heat exchanger Hb1 by exchanging heat with the refrigerant in the heat source side unit Hs1. The heat transfer medium cooled or heated by the heat source side unit Hs1 flows through the four-way valve Fw2 to the heat exchanger Hc1 of the load side unit Ws1.

[0017] The heat exchanger Hc1 performs heat exchange between the heat transfer medium cooled or heated by the heat source unit Hs1 and the air surrounding the heat exchanger Hc1. Air is blown into the heat exchanger Hc1 from a fan (not shown). This promotes heat exchange between the heat transfer medium inside the heat exchanger Hc1 and the air surrounding the heat exchanger Hc1. The heat exchanger Hc1 may be placed, for example, inside a building. In the refrigeration cycle device 100, the air temperature around the heat exchanger Hc1 is adjusted by circulating the heat transfer medium cooled or heated by the heat source unit Hs1 in the circulation channel Cr1.

[0018] Pump Pm1 is a device that circulates the heat transfer medium in the circulation channel Cr1. In the example shown in Figure 1, pump Pm1 discharges the heat transfer medium in the direction in which the four-way valve Fw2 is located. The four-way valve Fw2 is a valve that switches the state of the circulation channel Cr1. When the four-way valve Fw2 is switched, the direction in which the heat transfer medium flows through the heat exchanger Hb1 is switched.

[0019] The heat source unit Hs1 has a circulation channel Cr2 through which the refrigerant circulates. The heat source unit Hs1 comprises a four-way valve Fw1, a compressor C1, a heat exchanger Ha1, a pressure reducing device Ea1, and an accumulator Ac1. The four-way valve Fw1, compressor C1, heat exchangers Ha1 and Hb1, pressure reducing device Ea1, and accumulator Ac1 are all arranged on the circulation channel Cr2.

[0020] In Figure 1, the compressor C1 compresses the refrigerant, changing the state of the refrigerant in the circulation channel C2 to a high-temperature, high-pressure gaseous state, and sends it to the heat exchanger Ha1 via the four-way valve Fw1. The heat exchanger Ha1 performs heat exchange between the air surrounding the heat exchanger Ha1 and the high-temperature, high-pressure gaseous refrigerant. Air is blown into the heat exchanger Ha1 from a fan (not shown). This promotes heat exchange between the refrigerant and the air surrounding the heat exchanger Ha1. The heat exchanger Ha1 condenses the high-temperature, high-pressure gaseous refrigerant, changing the state of the refrigerant in the circulation channel Cr2 to a high-temperature, high-pressure gas-liquid mixture state.

[0021] The refrigerant, having changed into a gas-liquid mixture, is sent to the pressure reducing device Ea1. The pressure reducing device Ea1 is a device that reduces the pressure of the refrigerant, such as a capillary tube or an expansion valve. The pressure reducing device Ea1 reduces the pressure of the refrigerant in the gas-liquid mixture state, changing it into a gas-liquid mixture state that is low temperature and low pressure. The refrigerant in the gas-liquid mixture state, which is low temperature and low pressure, reaches the heat exchanger Hb1, where it exchanges heat with the heat transfer medium in the circulation channel Cr1. As a result, the heat transfer medium circulating in the circulation channel Cr1 is cooled.

[0022] Due to the heat exchange in the heat exchanger Hb1, the refrigerant in the circulation channel Cr2 changes from a low-temperature, low-pressure gas-liquid mixture to a low-temperature, low-pressure gaseous state. The refrigerant, now in a low-temperature, low-pressure gaseous state, is temporarily stored in the accumulator Ac1 via the four-way valve Fw1 from the heat exchanger Hb1, and then returns to the compressor C1, circulating within the circulation channel Cr2.

[0023] From the state shown in Figure 1, the four-way valve Fw1 is switched, causing the refrigeration cycle device 100 to transition to a heating state. In this case, the refrigerant in the circulation channel Cr2 circulates in the order of compressor C1, heat exchanger Hb1, pressure reducing device Ea1, and heat exchanger Ha1. That is, high-temperature, high-pressure refrigerant is discharged from compressor C1 to heat exchanger Hb1. The four-way valve Fw1 switches the direction of refrigerant flow between the direction in which the refrigerant discharged from compressor C1 flows into heat exchanger Ha1 and the direction in which the refrigerant discharged from compressor C1 flows into pressure reducing device Ea1 via heat exchanger Hb1.

[0024] The control device 10 controls various components included in the refrigeration cycle device 100. In this embodiment, the control device 10 is configured to communicate with the four-way valves Fw1 and Fw2 and controls the state of the four-way valves Fw1 and Fw2.

[0025] The lower part of Figure 1 shows a block diagram illustrating the configuration of the control device 10. The control device 10 comprises one or more processors 11, a communication interface (I / F) 12, memory 13, and storage 14. The components within the control device 10 are connected to each other via a bus (not shown) to enable data communication. The control device 10 may be an information processing device dedicated to the refrigeration cycle device 100, or it may be implemented using a general-purpose PC.

[0026] The communication interface 12 communicates with the four-way valves Fw1 and Fw2 via a network. The communication interface 12 has the hardware necessary for wired communication and / or the hardware necessary for wireless communication. Note that all or part of the processing of the communication interface 12 may be implemented by the processor 11.

[0027] The processor 11 is a processing unit (processing means) for controlling the circulation direction of the refrigerant and heat transfer medium. In this disclosure, the term "processor" means, for example, a processing circuit such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), or GPU (Graphics Processing Unit). The term "processor" includes processing circuits that execute processing according to instruction codes written in a program, processing circuits that integrate multiple functions such as a SoC (System on Chip), and hardwired circuits.

[0028] Memory 13 is a volatile storage device (storage medium) accessible by the processor 11, and may include, for example, DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory). Storage 14 is a non-volatile storage device (storage medium) accessible by the processor 11, and may include, for example, a hard disk or flash memory. Storage 14 may also be a storage medium that can be attached to or removed from the control device 10, such as an optical disc and cartridge.

[0029] The storage 14 stores a program 15 that is executed by the processor 11. The processor 11 reads the program 15, loads it into the memory 13, and executes it. The program 15 is a program for controlling the four-way valves Fw1 and Fw2. The memory 13 contains the instruction code for implementing the processing described later in Figure 3. The memory 13 is not limited to a volatile storage device (auxiliary storage device), but may also be a non-volatile storage device (main memory device). In this specification, the term "memory" includes at least volatile memory and non-volatile storage.

[0030] In such a water-type refrigeration cycle device 100, heat exchange takes place in the heat exchanger Hb1 between the heat transfer medium flowing through the circulation channel Cr1 and the refrigerant flowing through the circulation channel Cr2. As shown in Figure 1, in the heat exchanger Hb1, the direction in which the heat transfer medium flows through the circulation channel Cr1 is opposite to the direction in which the refrigerant flows through the circulation channel Cr1. Hereafter, the state in which the direction in which the refrigerant flows and the direction in which the heat transfer medium flows are opposite in the heat exchanger Hb1 will be referred to as counterflow.

[0031] When the circulation direction of the heat transfer medium and refrigerant in the heat exchanger Hb1 is counter-flow, the efficiency of heat exchange between the refrigerant and the heat transfer medium is higher than when the circulation direction is not counter-flow. When the four-way valve Fw1 is switched to switch from a cooling state to a heating state, the direction in which the refrigerant flows through the circulation channel Cr1 in the heat exchanger Hb1 becomes reversed, the circulation direction of the heat transfer medium and refrigerant in the heat exchanger Hb1 is no longer counter-flow, and the efficiency of heat exchange decreases. Therefore, in the refrigeration cycle device 100 of this embodiment, in order to generate counter-flow early after the four-way valve Fw1 is switched, the control device 10 switches the four-way valve Fw2 based on the fact that the control device 10 has switched the four-way valve Fw1, thereby generating counter-flow early.

[0032] <Processing Procedure> Figure 2 is a flowchart showing the process when switching between the cooling state and the heating state in Embodiment 1. The control device 10 implements the process shown in Figure 2 by executing the program 15.

[0033] The control device 10 determines whether or not it has received a switching command for the four-way valve Fw1 (step S101). A switching command for the four-way valve Fw1 is a command from the user to switch from the cooling state to the heating state or from the heating state to the cooling state. The user sends a switching command for the four-way valve Fw1 to the control device 10 using an input device (not shown).

[0034] If the control device 10 does not accept a switching command for the four-way valve Fw1 (NO in step S101), it terminates the process. If the control device 10 accepts a switching command for the four-way valve Fw1 (YES in step S101), it switches the state of the four-way valve Fw1 (step S102). That is, the direction in which the refrigerant flows in the heat exchanger Hb1 becomes reversed. Subsequently, the control device 10 switches the state of the four-way valve Fw2 (step S103) and terminates the process. That is, the direction in which the heat transfer medium flows in the heat exchanger Hb1 becomes reversed. The four-way valve Fw2 switches the direction in which the heat transfer medium flows so that the direction in which the refrigerant flows and the direction in which the heat transfer medium flows are opposite in the heat exchanger Hb1.

[0035] Figure 3 is a diagram illustrating the refrigeration cycle device 100 when it is in a heating state. As shown in Figure 3, the state of the four-way valves Fw1 and Fw2 has changed from the state shown in Figure 1. As a result, counterflow is occurring inside the heat exchanger Hb1.

[0036] Thus, in this embodiment, the control device 10 controls the four-way valves Fw1 and Fw2. By controlling the four-way valves Fw1 and Fw2 using the control device 10, it becomes possible to switch the four-way valve Fw2 soon after the four-way valve Fw1 is switched, making it possible to maintain a state in which the circulation direction of the heat medium and refrigerant in the heat exchanger Hb1 is counterflow. In other words, in the refrigeration cycle device 100 of this embodiment, it is possible to suppress a decrease in the efficiency of heat exchange in the heat exchanger Hb1.

[0037] The heat source unit Hs1 may correspond to the "first refrigerant circuit" in this disclosure. The refrigerant circulating in the circulation channel Cr2 may correspond to the "first refrigerant" in this disclosure. The four-way valve Fw1 may correspond to the "first four-way valve" in this disclosure. The heat exchanger Ha1 may correspond to the "first heat exchange" in this disclosure.

[0038] The load-side unit Ws1 may correspond to the "second refrigerant circuit" in this disclosure. The heat transfer medium circulating in the circulation channel Cr1 may correspond to the "second refrigerant" in this disclosure. The four-way valve Fw2 may correspond to the "second four-way valve" in this disclosure. The heat exchanger Hc1 may correspond to the "second heat exchange" in this disclosure. The heat exchanger Hb1 may correspond to the "heat exchanger that exchanges heat between the first refrigerant and the second refrigerant" in this disclosure.

[0039] Embodiment 2. In Embodiment 1, an example was described in which only a four-way valve Fw2 is used to switch the direction of flow of the heat transfer medium within the heat exchanger Hb1. In Embodiment 2, an example is described in which, in addition to the four-way valve Fw2, valves V21 and V22 are also switched when switching the direction of flow of the heat transfer medium within the heat exchanger Hb1. Note that in Embodiment 2, the description of configurations that overlap with Embodiment 1 will not be repeated.

[0040] Figure 4 is a diagram illustrating the refrigeration cycle device 100A in Embodiment 2. Figure 4 shows the refrigeration cycle device 100A in the cooling state in Embodiment 2. The load-side unit Ws1 in the refrigeration cycle device 100A includes valves V21 and V22 in addition to the four-way valve Fw2. Valves V21 and V22 are typically solenoid valves. The control device 10 can control the state of valves V21 and V22 between a state in which the flow of the heat transfer medium is blocked and a state in which the heat transfer medium is allowed to pass through. Hereinafter, in the state of valves V21 and V22, the state in which the flow of the heat transfer medium is blocked will be referred to as the "closed state," and the state in which the heat transfer medium is allowed to pass through will be referred to as the "open state."

[0041] Valve V21 is located between the four-way valve Fw2 and the pump Pm1 in the circulation path Cr1. The load-side unit Ws1 in Embodiment 2 has a bypass path Bp1 that does not pass through the heat exchanger Hc1, the four-way valve Fw2, and valve V21. In other words, the bypass path Bp1 bypasses the path that passes through the heat exchanger Hc1, the four-way valve Fw2, and valve V21 from the path between valve V21 and the pump Pm1. Valve V22 is located on the bypass path Bp1.

[0042] In Embodiment 2, as shown in FIG. 4, when the refrigeration cycle apparatus 100A is in the cooling state, the state of the valve V21 is controlled to the open state, and the state of the valve V22 is controlled to the closed state. In the cooling state, the heat medium in the circulation flow path Cr1 does not pass through the bypass flow path Bp1, but only passes through the flow path passing through the valve V21, the four-way valve Fw2, and the heat exchanger Hb1, and flows into the heat exchanger Hc1. As will be described later, when the refrigeration cycle apparatus 100A is in the heating state, the state of the valve V21 is controlled to the closed state, and the state of the valve V22 is controlled to the open state.

[0043] FIG. 5 is a flowchart showing the process when switching between the cooling state and the heating state in Embodiment 2. The control device 10 determines whether or not it has received a switching command for the four-way valve Fw1 (step S201). When the control device 10 has not received a switching command for the four-way valve Fw1 (NO in step S201), the process ends.

[0044] When the control device 10 has received a switching command for the four-way valve Fw1 (YES in step S201), the control device 10 switches the state of the four-way valve Fw1 (step S202). The direction in which the refrigerant flows in the heat exchanger Hb1 is switched.

[0045] The control device 10 controls the state of the valve V22 to the open state (step S203). The states of both the valves V21 and V22 become the open state. The heat medium in the circulation flow path Cr1 passes through both the bypass flow path Bp1 and the flow path passing through the valve V21, the four-way valve Fw2, and the heat exchanger Hb1, and flows into the heat exchanger Hc1. The control device 10 controls the state of the valve V21 to the closed state (step S204). The heat medium in the circulation flow path Cr1 passes only through the bypass flow path Bp1 and flows into the heat exchanger Hc1.

[0046] FIG. 6 is a diagram showing the state of the refrigeration cycle apparatus 100A at the end of the process of step S204. As shown in FIG. 6, the heat medium circulates in the circulation flow path Cr1 by passing only through the bypass flow path Bp1 without passing through the flow path passing through the valve V21, the four-way valve Fw2, and the heat exchanger Hb1.

[0047] Returning to FIG. 4, the control device 10 switches the state of the four-way valve Fw2 (step S205). In the circulation flow path Cr1, when the heat medium flows through the heat exchanger Hb1, the flow direction becomes the reverse direction. The control device 10 controls the state of the valve V21 to the open state (step S206). The heat medium in the circulation flow path Cr1 passes through both the bypass flow path Bp1 and the flow path passing through the valve V21, the four-way valve Fw2, and the heat exchanger Hb1, and flows into the heat exchanger Hc1. At this time, compared with when the refrigeration cycle device 100A is in the cooling state, the flow direction of the heat medium flowing through the heat exchanger Hb1 becomes the reverse direction.

[0048] The control device 10 controls the state of the valve V22 to the closed state (step S207) and ends the process. After the process of step S207 ends, the refrigeration cycle device 100A enters the heating state. FIG. 7 is a diagram showing the state of the refrigeration cycle device 100A when the process of step S207 ends. As shown in FIG. 7, the heat medium circulates in the circulation flow path Cr1 by passing only through the flow path passing through the valve V21, the four-way valve Fw2, and the heat exchanger Hb1 without passing through the bypass flow path Bp1. Further, due to the switching of the state of the four-way valve Fw2 in step S205, a countercurrent occurs in the heat exchanger Hb1.

[0049] Thus, in the second embodiment, when the four-way valve Fw2 is switched, the heat medium is controlled to temporarily pass through the bypass flow path Bp1. Thereby, when the four-way valve Fw2 is switched, it is possible to suppress an instantaneous sharp increase in the pressure of the heat medium in the circulation flow path Cr1. An instantaneous sharp increase in the pressure of the heat medium generated when the four-way valve Fw2 is switched is sometimes referred to as a water hammer. In the second embodiment, the components in the load-side unit Ws1 can be protected from the water hammer.

[0050] In Embodiment 2, as in Embodiment 1, the control device 10 controls the four-way valves Fw1 and Fw2. Therefore, after the four-way valve Fw1 is switched, it becomes possible to switch the four-way valve Fw2 soon after, making it possible to maintain a state in which the circulation direction of the heat medium and refrigerant in the heat exchanger Hb1 is counterflow. In other words, even in the refrigeration cycle device 100A in Embodiment 2, it is possible to suppress a decrease in the efficiency of heat exchange in the heat exchanger Hb1. In Embodiment 2, valve V21 corresponds to the "first solenoid valve" in this disclosure, and valve V22 may correspond to the "second solenoid valve" in this disclosure.

[0051] Embodiment 3. In Embodiment 1, an example was described in which a four-way valve Fw2 capable of switching the direction of flow of the heat transfer medium within the heat exchanger Hb1 is provided in the circulation channel Cr1. In Embodiment 3, an example is described in which a detachable housing Bx1 capable of switching the direction of flow of the heat transfer medium within the heat exchanger Hb1 is provided. In Embodiment 3, the description of configurations that overlap with Embodiment 1 will not be repeated.

[0052] Figure 8 is a diagram illustrating the refrigeration cycle device 100B in Embodiment 3. Figure 8 shows the refrigeration cycle device 100B in the heating state in Embodiment 3. As shown in Figure 8, in Embodiment 3 as well, when in the heating state, counterflow occurs in the heat exchanger Hb1.

[0053] The load-side unit Ws1 of Embodiment 3 has a housing Bx1 that constitutes part of the circulation channel Cr1. The housing Bx1 has insertion ports Pr1 to Pr4 into which the pipes constituting the circulation channel Cr1 can be inserted. As shown in Figure 8, insertion ports Pr2 and Pr3 are connected to the heat exchanger Hb1. The housing Bx1 has valves V31 to V34 inside. The control device 10 can control the state of each of the valves V31 to V34 between an open state and a closed state.

[0054] In Embodiment 3, when the refrigeration cycle device 100B is in a heating state, the states of valves V31 and V34 are controlled to be open, and the states of valves V32 and V33 are controlled to be closed. As shown in Figure 8, the heat transfer medium discharged from pump Pm1 flows through the circulation path Cr1 in the following order: inlet Pr1, valve V31, inlet Pr2, heat exchanger Hb1, inlet Pr3, valve V34, inlet Pr4, and heat exchanger Hc1.

[0055] Figure 9 is a flowchart showing the process when switching from a heating state to a cooling state in Embodiment 3. The control device 10 determines whether or not it has received a command to switch from a heating state to a cooling state (step S301). If the control device 10 does not receive a command to switch from a heating state to a cooling state (NO in step S301), it terminates the process.

[0056] When the control device 10 receives a command to switch from the heating state to the cooling state (YES in step S301), it switches the state of the four-way valve Fw1 (step S302). Subsequently, the control device 10 controls the state of valve V33 to the open state (step S303). The control device 10 controls the state of valve V31 to the closed state (step S304). The control device 10 controls the state of valve V32 to the open state (step S305). The control device 10 controls the state of valve V34 to the closed state (step S306) and terminates the process. Upon completion of the process in step S306, the state of the refrigeration cycle device 100B switches from the heating state to the cooling state.

[0057] Figure 10 shows the state of the refrigeration cycle device 100B at the end of step S306. Figure 10 shows the refrigeration cycle device 100B in the cooling state. As shown in Figure 10, valves V31 and V34 are in the closed state, and valves V32 and V33 are in the open state.

[0058] In the cooling state shown in Figure 10, the heat transfer medium discharged from pump Pm1 flows through the circulation channel Cr1 in the following order: inlet Pr1, valve V33, inlet Pr3, heat exchanger Hb1, inlet Pr2, valve V32, inlet Pr4, and heat exchanger Hc1. By switching the states of valves V31 to V34 as shown in the flowchart of Figure 9, the flow direction of the heat transfer medium flowing through heat exchanger Hb1 is reversed compared to Figure 8. As a result, in Embodiment 3 as well, when switching from the heating state to the cooling state, the flow direction of the heat transfer medium flowing through heat exchanger Hb1 can be reversed, and counterflow can be generated in heat exchanger Hb1 at an early stage.

[0059] Figure 11 is a flowchart showing the process when switching from the cooling state to the heating state in Embodiment 3. The control device 10 determines whether or not it has received a command to switch from the cooling state to the heating state (step S311). If the control device 10 does not receive a command to switch from the cooling state to the heating state (NO in step S311), it terminates the process.

[0060] When the control device 10 receives a command to switch from the cooling state to the heating state (YES in step S311), it switches the state of the four-way valve Fw1 (step S312). Subsequently, the control device 10 controls the state of valve V33 to the closed state (step S313). The control device 10 controls the state of valve V31 to the open state (step S314). The control device 10 controls the state of valve V32 to the closed state (step S315). The control device 10 controls the state of valve V34 to the open state (step S316) and terminates the process. Upon completion of the process in step S316, the state of the refrigeration cycle device 100B switches from the cooling state to the heating state.

[0061] Thus, in Embodiment 3, when switching between heating and cooling states, the state of valves V31 to V34 housed in the detachable housing Bx1 is switched. This makes it possible to change the flow direction of the heat transfer medium in the heat exchanger Hb1 simply by installing the housing Bx1 inside the load-side unit Ws1 when constructing the refrigeration cycle device 100B. Furthermore, in Embodiment 3, it is possible to switch the flow direction of the heat transfer medium in the heat exchanger Hb1 without using a four-way valve.

[0062] In Embodiment 3, as in Embodiment 1, after the four-way valve Fw1 is switched, the control device 10 can quickly switch the flow direction of the heat medium in the heat exchanger Hb1, and the state in which the circulation direction of the heat medium and refrigerant in the heat exchanger Hb1 is counterflow can be maintained. In other words, even in the refrigeration cycle device 100B in Embodiment 3, a decrease in the efficiency of heat exchange in the heat exchanger Hb1 can be suppressed. Note that the valves V31 to V34 in Embodiment 3 may correspond to "at least one third solenoid valve" in this disclosure.

[0063] In Embodiment 3, the flow path within the housing Bx1 is merely an example and is not limited to the configuration shown in Figures 8 and 10. That is, it is sufficient that the flow direction of the heat transfer medium in the heat exchanger Hb1 can be switched by switching the state of valves V31 to V34, and the arrangement of valves V31 to V34, the arrangement of inlet Pr1 to V4, and the configuration of the flow path are not limited to the example in Figures 8 and 10.

[0064] Embodiment 4. Embodiment 3 described an example in which a detachable housing Bx1 is provided. Embodiment 4 describes an example in which a tank Tk1 capable of storing a heat transfer medium is arranged inside the detachable housing Bx1. In Embodiment 4, the description of configurations that overlap with those in Embodiment 3 will not be repeated.

[0065] Figure 12 is a diagram illustrating the refrigeration cycle device 100C in Embodiment 4. Figure 12 shows the refrigeration cycle device 100C in the heating state in Embodiment 4. As shown in Figure 12, in Embodiment 4 as well, when in the heating state, counterflow occurs in the heat exchanger Hb1.

[0066] The housing Bx1 of Embodiment 4 includes valves V41 to V44 and a tank Tk1 capable of storing a heat transfer medium. The tank Tk1 has insertion ports Tr1 to Tr3. Within the housing Bx1, insertion port Tr1 is connected to insertion port Pr1. Within the housing Bx1, insertion port Tr2 is connected to valve V41. Within the housing Bx1, insertion port Tr3 is connected to valve V42. The control device 10 can control the state of each of the valves V41 to V44 between an open state and a closed state.

[0067] In Embodiment 4, when the refrigeration cycle device 100C is in a heating state, the states of valves V41 and V44 are controlled to be open, and the states of valves V42 and V43 are controlled to be closed. As shown in Figure 12, the heat transfer medium discharged from pump Pm1 flows through the circulation channel Cr1 in the following order: inlet Pr1, inlet Tr1, inlet Tr2, valve V41, inlet Pr2, heat exchanger Hb1, inlet Pr3, valve V44, inlet Pr4, and heat exchanger Hc1. That is, the heat transfer medium flowing through the circulation channel Cr1 passes through tank Tk1.

[0068] Figure 13 is an external view of the housing Bx1 in the heating state in Embodiment 4. The housing Bx1 in Embodiment 4 has a rectangular parallelepiped shape. In the following description, insertion openings Pr1 to Pr4 are arranged on the front surface of the housing Bx1. The direction along the long side of the surface on which insertion openings Pr1 to Pr4 are located is defined as the "Z-axis direction," the direction perpendicular to the Z-axis direction and along the short side of the surface on which insertion openings Pr1 to Pr4 are located is defined as the "Y-axis direction," and the direction perpendicular to both the Z-axis and the Y-axis is defined as the "X-axis direction."

[0069] In Embodiment 4, the Z-axis direction is vertical. That is, the heat transfer medium, being a fluid, flows from the positive Z-axis direction to the negative Z-axis direction due to the influence of gravity. Hereafter, the positive Z-axis direction in each figure may be referred to as the upper side, and the negative Z-axis direction as the lower side.

[0070] The housing Bx1 has a tank Tk1 inside. Figure 13 shows the insertion ports Tr1 to Tr3 of the tank Tk1. In Figure 13, the valves V41 to V44 are not shown. The insertion ports Tr1 to Tr3 are positioned to overlap with insertion ports Pr1 to Pr3 when viewed from the negative X-axis side in a plan view. This allows the tank Tk1 to be connected from the external configuration of the housing Bx1 using a single rod-shaped pipe.

[0071] As shown in Figure 13, the housing Bx1 is installed such that the inlet Pr1 is positioned on the negative Z-axis side compared to the inlets Pr2 and Pr3. That is, the inlet Tr1 is positioned lower than the inlets Tr2 and Tr3. As shown in Figures 12 and 13, the heat transfer medium flowing through the circulation channel Cr1 flows from inlet Tr1 into tank Tk1 and out through inlet Tr2 to the outside of tank Tk1.

[0072] In Embodiment 4, a heat transfer medium is stored in a tank Tk1 formed on the circulation channel Cr1. Compared to a refrigeration cycle device 100 without a tank Tk1, the capacity of the heat transfer medium circulating in the circulation channel Cr1 is increased. This makes it possible to suppress the degree to which external factors such as sudden pressure fluctuations and sudden temperature changes in the circulation channel Cr1 affect the heat transfer medium in the circulation channel Cr1. In other words, the tank Tk1 protects the circulation in the circulation channel Cr1 from external factors.

[0073] Figure 14 is a flowchart showing the process when switching from a heating state to a cooling state in Embodiment 4. The control device 10 determines whether or not it has received a command to switch from a heating state to a cooling state (step S401). If the control device 10 does not receive a command to switch from a heating state to a cooling state (NO in step S401), it terminates the process.

[0074] When the control device 10 receives a command to switch from the heating state to the cooling state (YES in step S401), it switches the state of the four-way valve Fw1 (step S402). Subsequently, the control device 10 controls the state of valve V42 to the open state (step S403). The control device 10 controls the state of valve V41 to the closed state (step S404). The control device 10 controls the state of valve V43 to the open state (step S405). The control device 10 controls the state of valve V44 to the closed state (step S406) and ends the process. Upon completion of the process in step S406, the state of the refrigeration cycle device 100C switches from the heating state to the cooling state.

[0075] Figure 15 shows the state of the refrigeration cycle device 100C at the end of step S406. Figure 15 shows the refrigeration cycle device 100C in the cooling state. As shown in Figure 15, valves V41 and V44 are in the closed state, and valves V42 and V43 are in the open state.

[0076] In the cooling state shown in Figure 15, the heat transfer medium discharged from pump Pm1 flows through the circulation channel Cr1 in the following order: inlet Pr1, inlet Tr1, inlet Tr3, valve V42, inlet Pr3, heat exchanger Hb1, inlet Pr2, valve V43, inlet Pr4, and heat exchanger Hc1. Even in the cooling state, the heat transfer medium flowing through the circulation channel Cr1 passes through tank Tk1.

[0077] As the states of valves V41 to V44 are switched as shown in the flowchart of Figure 14, the flow direction of the heat transfer medium flowing through the heat exchanger Hb1 is reversed compared to Figure 12. This allows the flow direction of the heat transfer medium flowing through the heat exchanger Hb1 to be reversed when switching from the heating state to the cooling state in Embodiment 4, thereby enabling the generation of counterflow in the heat exchanger Hb1 at an early stage.

[0078] Figure 16 is an external view of the housing Bx1 in the cooling state in Embodiment 4. As shown in Figures 15 and 16, in the cooling state, the heat transfer medium flowing through the circulation channel Cr1 flows into the tank Tk1 from the inlet Tr1 and out to the outside of the tank Tk1 from the inlet Tr3.

[0079] In Embodiment 4, in both the cooling and heating states, the heat transfer medium flowing through the circulation channel Cr1 flows into the tank Tk1 from inlet Tr1, which is formed at a lower position than the inlet ports Tr2 and Tr3. Therefore, when the heat transfer medium in the tank Tk1 is filled up to the positions of inlet ports Tr2 and Tr3, circulation within the circulation channel Cr1 can begin.

[0080] In other words, circulation within the circulation channel Cr1 does not begin until the heat transfer medium in tank Tk1 is filled to a specified capacity. As a result, in the refrigeration cycle device 100C of Embodiment 4, circulation within the circulation channel Cr1 can begin only after tank Tk1, which protects the circulation within the circulation channel Cr1, has become functional.

[0081] Figure 17 is a flowchart showing the process when switching from the cooling state to the heating state in Embodiment 4. The control device 10 determines whether or not it has received a command to switch from the cooling state to the heating state (step S411). If the control device 10 does not receive a command to switch from the cooling state to the heating state (NO in step S411), it terminates the process.

[0082] When the control device 10 receives a command to switch from the cooling state to the heating state (YES in step S411), it switches the state of the four-way valve Fw1 (step S412). Subsequently, the control device 10 controls the state of valve V42 to the closed state (step S413). The control device 10 controls the state of valve V41 to the open state (step S414). The control device 10 controls the state of valve V43 to the closed state (step S415). The control device 10 controls the state of valve V44 to the open state (step S416) and terminates the process. Upon completion of the process in step S416, the state of the refrigeration cycle device 100C switches from the cooling state to the heating state.

[0083] Thus, in Embodiment 4, when switching between heating and cooling states, the state of valves V41 to V44 housed in the housing Bx1 is switched. In Embodiment 4, as in Embodiment 1, after the four-way valve Fw1 is switched, the control device 10 can quickly switch the flow direction of the heat transfer medium in the heat exchanger Hb1, and the state in which the circulation direction of the heat transfer medium and refrigerant in the heat exchanger Hb1 is counterflow can be maintained. In other words, even in the refrigeration cycle device 100C of Embodiment 4, a decrease in the efficiency of heat exchange in the heat exchanger Hb1 can be suppressed.

[0084] In Embodiment 4, the insertion port Tr1 may correspond to the "inlet" in this disclosure. The insertion port Tr2 or insertion port Tr3 may correspond to the "outlet" in this disclosure.

[0085] Embodiment 5. In Embodiment 1, an example was described in which a four-way valve Fw2, positioned on the circulation channel Cr1, is used to switch the direction of flow of the heat transfer medium within the heat exchanger Hb1. In Embodiment 5, an example is described in which a four-way valve Fw3, positioned on the circulation channel Cr2 instead of the circulation channel Cr1, is used to switch the direction of flow of the heat transfer medium within the heat exchanger Hb1. Note that in Embodiment 5, the description of configurations that overlap with Embodiment 1 will not be repeated.

[0086] Figure 18 is a diagram illustrating the refrigeration cycle device 100D in the heating state according to Embodiment 5. The heat source side unit Hs1 in the refrigeration cycle device 100D is equipped with a four-way valve Fw3 in addition to a four-way valve Fw1. The control device 10 can control the state of the four-way valves Fw1 and Fw3. Similar to the four-way valve Fw1, the four-way valve Fw3 is configured such that the direction in which the refrigerant flows through the circulation channel Cr1 in the heat exchanger Hb1 is reversed by switching the state of the four-way valve Fw3.

[0087] As shown in Figure 18, the refrigerant discharged from the compressor C1 circulates through the circulation path Cr2 in the following order: four-way valve Fw1, four-way valve Fw3, heat exchanger Hb1, pressure reducing device Ea1, heat exchanger Ha1, and four-way valve Fw1. That is, high-temperature, high-pressure refrigerant flows into the heat exchanger Hb1, and the refrigeration cycle device 100D enters a heating state.

[0088] Figure 19 is a flowchart showing the process for switching between the cooling state and the heating state in Embodiment 5. The control device 10 determines whether or not it has received a switching command for the four-way valve Fw1 (step S501).

[0089] If the control device 10 does not accept a switching command for the four-way valve Fw1 (NO in step S501), it terminates the process. If the control device 10 accepts a switching command for the four-way valve Fw1 (YES in step S501), it switches the state of the four-way valve Fw1 (step S502). That is, the direction in which the refrigerant flows in the heat exchanger Hb1 becomes reversed. Subsequently, the control device 10 switches the state of the four-way valve Fw3 (step S503) and terminates the process. That is, the direction in which the refrigerant flows through the circulation channel Cr1 in the heat exchanger Hb1 becomes reversed again, returning to the state before step S502 was processed.

[0090] Figure 20 is a diagram illustrating the refrigeration cycle device 100D in the cooling state according to Embodiment 5. As shown in Figure 20, the refrigerant discharged from the compressor C1 circulates through the circulation path Cr2 in the following order: four-way valve Fw1, heat exchanger Ha1, pressure reducing device Ea1, four-way valve Fw3, heat exchanger Hb1, four-way valve Fw3, and four-way valve Fw1. That is, low-temperature, low-pressure refrigerant flows into the heat exchanger Hb1, and the refrigeration cycle device 100D enters a cooling state.

[0091] Thus, in Embodiment 5, when the four-way valve Fw3 is switched, the direction of refrigerant flow in the heat exchanger Hb1 remains constant, regardless of whether the refrigeration cycle device 100D is in a cooling or heating state. As a result, the refrigeration cycle device 100D can generate counterflow without providing a configuration to control the flow direction of the heat transfer medium within the load-side unit Ws1.

[0092] In Embodiment 5, as in Embodiment 1, the control device 10 controls the four-way valves Fw1 and Fw3. Therefore, after the four-way valve Fw1 is switched, it becomes possible to switch the four-way valve Fw3 soon after, making it possible to maintain a state in which the circulation direction of the heat medium and refrigerant in the heat exchanger Hb1 is counterflow. In other words, even in the refrigeration cycle device 100D in Embodiment 5, it is possible to suppress a decrease in the efficiency of heat exchange in the heat exchanger Hb1. In Embodiment 5, the four-way valve Fw3 may correspond to the "third four-way valve" in this disclosure.

[0093] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

[0094] 10 Control device, 11 Processor, 12 Communication interface, 13 Memory, 14 Storage, 15 Program, V21, V22, V31-V34, V41-V44 Valves, 100, 100A-100D Refrigeration cycle device, Ac1 Accumulator, Bp1 Bypass channel, Bx1 Housing, C1 Compressor, Cr1, Cr2 Circulation channel, Ea1 Pressure reducing device, Fw1-Fw3 Four-way valve, Ha1, Hb1, Hc1 Heat exchanger, Hs1 Heat source side unit, Pm1 Pump, Pr1-Pr4, Tr1-Tr3 Inlet, Tk1 Tank, Ws1 Load side unit.

Claims

1. A refrigeration cycle device comprising: a first refrigerant circuit comprising a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve, configured to circulate a first refrigerant; a second refrigerant circuit comprising a pump and a second heat exchanger, configured to circulate a second refrigerant; a heat exchanger for exchanging heat between the first refrigerant and the second refrigerant; and a control device for controlling the first refrigerant circuit and the second refrigerant circuit, wherein the control device can control the first four-way valve to switch the direction in which the first refrigerant flows between the direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and the direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device, and further comprising at least one switching device for switching the direction in which the first refrigerant or the second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite in the heat exchanger. The control device controls the first four-way valve to switch the direction in which the first refrigerant flows, and controls the at least one switching device to switch the direction in which the first or second refrigerant flows, in a refrigeration cycle device.

2. The refrigeration cycle apparatus according to claim 1, wherein the at least one switching device includes a second four-way valve located in the second refrigerant circuit.

3. The refrigeration cycle apparatus according to claim 2, wherein the at least one switching device includes a first solenoid valve and a second solenoid valve, the first solenoid valve is located in the second refrigerant circuit between the second four-way valve and the pump, and the second solenoid valve is located on a bypass flow path that bypasses the flow path from the flow path between the first solenoid valve and the pump through the second four-way valve.

4. The refrigeration cycle apparatus according to claim 1, wherein the at least one switching device includes at least one third solenoid valve, and the refrigeration cycle apparatus further comprises a housing that houses a portion of the second refrigerant circuit on which the at least one third solenoid valve is located, and the housing is configured to be detachable from the second refrigerant circuit.

5. The refrigeration cycle apparatus according to any one of claims 1 to 4, further comprising a tank for storing the second refrigerant arranged in the second refrigerant circuit.

6. The refrigeration cycle apparatus according to claim 5, wherein the tank includes an inlet for introducing the second refrigerant from the pump and an outlet for discharging the second refrigerant to the heat exchanger, and the height at which the inlet is located is lower than the height at which the outlet is located.

7. The refrigeration cycle apparatus according to claim 1, wherein the at least one switching device includes a third four-way valve located in the first refrigerant circuit.

8. A control device for controlling a refrigeration cycle apparatus comprising a first refrigerant circuit configured to circulate a first refrigerant, a second refrigerant circuit configured to circulate a second refrigerant, and a heat exchanger for exchanging heat between the first refrigerant and the second refrigerant, wherein the first refrigerant circuit comprises a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve, the second refrigerant circuit comprises a pump and a second heat exchanger, the control device is capable of controlling the first four-way valve to switch the direction in which the first refrigerant flows between the direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and the direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device, and the refrigeration cycle apparatus further comprises at least one switching device for switching the direction in which the first refrigerant or the second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite in the heat exchanger. The control device controls the first four-way valve to switch the direction in which the first refrigerant flows, and controls the at least one switching device to switch the direction in which the first refrigerant or the second refrigerant flows.

9. A control method used in a control device for controlling a refrigeration cycle apparatus comprising a first refrigerant circuit configured to circulate a first refrigerant, a second refrigerant circuit configured to circulate a second refrigerant, and a heat exchanger for exchanging heat between the first refrigerant and the second refrigerant, wherein the first refrigerant circuit comprises a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve, the second refrigerant circuit comprises a pump and a second heat exchanger, the control device is capable of controlling the first four-way valve to switch the direction in which the first refrigerant flows between a direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and a direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device, the refrigeration cycle apparatus further comprises at least one switching device for switching the direction in which the first refrigerant or the second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows in the heat exchanger are opposite to each other, and the control method comprises, as a process to be executed by the control device, the step of controlling the first four-way valve to switch the direction in which the first refrigerant flows, A control method comprising the step of controlling at least one switching device to switch the direction in which the first refrigerant or the second refrigerant flows.

10. A control program used in a control device for a refrigeration cycle apparatus comprising a first refrigerant circuit configured to circulate a first refrigerant, a second refrigerant circuit configured to circulate a second refrigerant, and a heat exchanger for heat exchange between the first refrigerant and the second refrigerant, wherein the first refrigerant circuit comprises a compressor, a first heat exchanger, a pressure reducing device, and a first four-way valve, the second refrigerant circuit comprises a pump and a second heat exchanger, the control device is capable of controlling the first four-way valve to switch the direction in which the first refrigerant flows between the direction in which the first refrigerant discharged from the compressor flows into the first heat exchanger and the direction in which the first refrigerant discharged from the compressor flows into the pressure reducing device, the refrigeration cycle apparatus further comprises at least one switching device for switching the direction in which the first refrigerant or the second refrigerant flows so that the direction in which the first refrigerant flows and the direction in which the second refrigerant flows are opposite in the heat exchanger, and the control program comprises the steps of controlling the control device to switch the direction in which the first refrigerant flows by controlling the first four-way valve, A control program that causes the program to perform the step of controlling at least one switching device to switch the direction in which the first refrigerant or the second refrigerant flows.

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