Refrigeration cycle equipment

Abstract

After the heating operation is complete, the first refrigerant in the first refrigerant circuit is recovered into the heat source component. [Solution] The first flow path switching mechanism (15) can switch the flow path of the first refrigerant in the first refrigerant circuit (10) between a first flow path state in which the first refrigerant flows sequentially through the first compressor (11), the refrigerant heat exchanger (30), the first expansion valve (13), and the heat source heat exchanger (12), and a second flow path state in which the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12). In a refrigerant recovery operation in which the first refrigerant in the first refrigerant circuit (10) is recovered to the heat source element component (18) after the end of the heating operation, the control unit (100) drives the first refrigerant circuit (10) so that the flow path of the first refrigerant in the first refrigerant circuit (10) is switched from the first flow path state to the second flow path state and the first expansion valve (13) is closed.

Description

Technical Field

[0001] The present disclosure relates to a refrigeration cycle device.

Background Art

[0002] Patent Document 1 discloses a hot water supply device including a low-pressure refrigerant circuit and a high-pressure refrigerant circuit. The low-pressure refrigerant circuit and the high-pressure refrigerant circuit are connected by a cascade heat exchanger. In each of these refrigerant circuits, a refrigeration cycle is performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a refrigeration cycle device as described above, from the viewpoint of optimizing the management of the refrigerant, it is desirable to perform a refrigerant recovery operation after the completion of a heating operation such as a heating operation. The refrigerant recovery operation is an operation for recovering the refrigerant filled in the low-pressure refrigerant circuit to a heat source component such as a heat source heat exchanger of the low-pressure refrigerant circuit.

Means for Solving the Problems

[0005] A first aspect of the present disclosure relates to a refrigeration cycle device, which includes a first refrigerant circuit (10) in which a first refrigerant circulates, a second refrigerant circuit (20) in which a second refrigerant circulates, a refrigerant heat exchanger (30) that exchanges heat between the first refrigerant in the first refrigerant circuit (10) and the second refrigerant in the second refrigerant circuit (20), and a control unit (100) that controls the first refrigerant circuit (10) and the second refrigerant circuit (20). The first refrigerant circuit (10) includes a first compressor (11), a heat source element component (18) including a heat source heat exchanger (12), a first expansion valve (13), and a first flow path switching mechanism (15). The second refrigerant circuit (20) includes a second compressor (21), a heat exchanger (22), and a second expansion valve (23). The first expansion valve (13) is positioned between the heat source element component (18) and the refrigerant heat exchanger (30) in the first refrigerant circuit (10). The first flow path switching mechanism (15) is capable of switching the flow path of the first refrigerant in the first refrigerant circuit (10) between a first flow path state in which the first refrigerant flows sequentially through the first compressor (11), the refrigerant heat exchanger (30), the first expansion valve (13), and the heat source heat exchanger (12), and a second flow path state in which the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12). The control unit (100) In heating operation, the first refrigerant circuit (10) is driven so that the flow path of the first refrigerant in the first refrigerant circuit (10) is in the first flow path state, and the second refrigerant circuit (20) is driven so that the second refrigerant in the second refrigerant circuit (20) flows sequentially through the second compressor (21), the utilization heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30). In a refrigerant recovery operation in which the first refrigerant from the first refrigerant circuit (10) is recovered into the heat source element component (18) after the completion of the heating operation, the first refrigerant circuit (10) is driven such that the flow path of the first refrigerant in the first refrigerant circuit (10) is switched from the first flow path state to the second flow path state, and the first expansion valve (13) is closed.

[0006] In the first embodiment, during refrigerant recovery operation, the first refrigerant circuit (10) is driven to cause the flow path of the first refrigerant in the first refrigerant circuit (10) to become a second flow path state and the first expansion valve (13) to be closed, thereby generating a flow of first refrigerant that flows sequentially from the first expansion valve (13) through the refrigerant heat exchanger (30) and the first compressor (11) to reach the heat source heat exchanger (12). As a result, the first refrigerant remaining in the refrigerant heat exchanger (30) and the like can be recovered into the heat source element components (18), including the heat source heat exchanger (12).

[0007] A second aspect of this disclosure is, in the first aspect, The second refrigerant circuit (20) has a second flow path switching mechanism (24), The second flow path switching mechanism (24) is capable of switching the flow path of the second refrigerant in the second refrigerant circuit (20) between a third flow path state in which the second refrigerant flows sequentially through the second compressor (21), the utilization heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30), and a fourth flow path state in which the second refrigerant flows sequentially through the second compressor (21), the refrigerant heat exchanger (30), the second expansion valve (23), and the utilization heat exchanger (22). The control unit (100) In the heating operation described above, the second refrigerant circuit (20) is driven so that the flow path of the second refrigerant in the second refrigerant circuit (20) becomes the third flow path state. In the refrigerant recovery operation, the second refrigerant circuit (20) is driven so that the flow path of the second refrigerant in the second refrigerant circuit (20) switches from the third flow path state to the fourth flow path state. It is a refrigeration cycle device.

[0008] In the second embodiment, during refrigerant recovery operation, the second refrigerant circuit (20) is driven so that the flow path of the second refrigerant in the second refrigerant circuit (20) becomes a fourth flow path state, thereby allowing the second refrigerant in the second refrigerant circuit (20) to be released to the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30). This promotes the evaporation of the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30), thereby promoting the recovery of the first refrigerant during refrigerant recovery operation.

[0009] A third aspect of this disclosure is, in the first aspect, The control unit (100) drives the second refrigerant circuit (20) so that the second refrigerant flows sequentially through the second compressor (21), the utilization heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30) during the refrigerant recovery operation. The opening of the second expansion valve (23) in the refrigerant recovery operation is greater than the opening of the second expansion valve (23) in the heating operation. It is a refrigeration cycle device.

[0010] In the third embodiment, the second refrigerant circuit (20) is driven with the second expansion valve (23) opening greater than the second expansion valve (23) opening during the refrigerant recovery operation, thereby allowing the high-temperature, high-pressure second refrigerant discharged from the second compressor (21) to be released into the first refrigerant of the first refrigerant circuit (10) in the refrigerant heat exchanger (30). This promotes the evaporation of the first refrigerant of the first refrigerant circuit (10) in the refrigerant heat exchanger (30), thereby promoting the recovery of the first refrigerant during the refrigerant recovery operation.

[0011] A fourth aspect of this disclosure is that in any one of the first to third aspects, The heat source element component (18) includes the heat source heat exchanger (12) and the receiver (16), In the first flow path state, the first refrigerant flows sequentially from the first compressor (11) to the refrigerant heat exchanger (30), the receiver (16), the first expansion valve (13), and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), the heat source heat exchanger (12), and the receiver (16). It is a refrigeration cycle device.

[0012] In the fourth embodiment, during refrigerant recovery operation, the first refrigerant circuit (10) is driven to cause the flow path of the first refrigerant in the first refrigerant circuit (10) to become a second flow path state and the first expansion valve (13) to be closed, thereby generating a flow of first refrigerant that flows sequentially from the first expansion valve (13) through the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12) to the receiver (16). This allows the first refrigerant remaining in the refrigerant heat exchanger (30), etc., to be recovered into the heat source element component (18), including the heat source heat exchanger (12) and the receiver (16).

[0013] A fifth aspect of this disclosure is that in any one of the first to third aspects, The first refrigerant circuit (10) has an auxiliary heat exchanger (14), In the first flow path state, the first refrigerant flows from the first compressor (11) through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) then flows sequentially through the first expansion valve (13) and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows from the first expansion valve (13) through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) then flows sequentially through the first compressor (11) and the heat source heat exchanger (12). It is a refrigeration cycle device.

[0014] In the fifth aspect, in the refrigerant recovery operation, the first refrigerant circuit (10) is driven so that the flow path of the first refrigerant in the first refrigerant circuit (10) becomes the second flow path state and the first expansion valve (13) becomes the closed state, thereby generating a flow of the first refrigerant in which "the first refrigerant flows from the first expansion valve (13) through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) flows through the first compressor (11) and reaches the heat source heat exchanger (12)". Thereby, the first refrigerant remaining in the refrigerant heat exchanger (30), the auxiliary heat exchanger (14), etc. can be recovered to the heat source component part (18) including the heat source heat exchanger (12).

[0015] In the sixth aspect of the present disclosure, in any one of the first to fifth aspects, it includes an indoor unit (IU) provided indoors, the refrigerant heat exchanger (30) is housed in the indoor unit (IU) and is a refrigeration cycle device.

[0016] In the sixth aspect, by performing the refrigerant recovery operation after the heating operation is completed, it is possible to prevent the first refrigerant from remaining in the refrigerant heat exchanger (30) housed in the indoor unit (IU) provided indoors. Thereby, the refrigerant can be appropriately managed in the refrigeration cycle device (1).

[0017] In the seventh aspect of the present disclosure, in the fifth aspect, it includes an indoor unit (IU) provided indoors, the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) are housed in the indoor unit (IU) and is a refrigeration cycle device.

[0018] In the seventh aspect, by performing the refrigerant recovery operation after the heating operation is completed, it is possible to prevent the first refrigerant from remaining in the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) housed in the indoor unit (IU) provided indoors. Thereby, the refrigerant can be appropriately managed in the refrigeration cycle device (1).

[0019] The eighth aspect of this disclosure is the sixth or seventh aspect, The first refrigerant is flammable or toxic. It is a refrigeration cycle device.

[0020] In the eighth embodiment, by performing a refrigerant recovery operation after the heating operation is completed, it is possible to prevent flammable or toxic first refrigerants from remaining in the refrigerant heat exchanger (30) or auxiliary heat exchanger (14) housed in the indoor unit (IU) installed in the room. This allows for safe management of the refrigerant in the refrigeration cycle device (1). [Brief explanation of the drawing]

[0021] [Figure 1] Figure 1 is a piping diagram illustrating the configuration of a refrigeration cycle system according to Embodiment 1. [Figure 2] Figure 2 is a block diagram illustrating the connections of each part in the refrigeration cycle device according to Embodiment 1. [Figure 3] Figure 3 is a piping diagram illustrating the flow of refrigerant during heating operation. [Figure 4] Figure 4 is a piping diagram illustrating the flow of refrigerant during refrigerant recovery operation. [Figure 5] Figure 5 is a piping diagram illustrating the configuration of the refrigeration cycle system according to Embodiment 2 and the flow of refrigerant during refrigerant recovery operation. [Modes for carrying out the invention]

[0022] The embodiments will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, this disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of ​​this disclosure. Since the drawings are for conceptual explanation of this disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.

[0023] (Embodiment 1) Figure 1 illustrates the configuration of the refrigeration cycle device (1) of Embodiment 1. In this example, the refrigeration cycle device (1) constitutes a hot water supply device that generates hot water. The hot water generated by the hot water supply device is stored in a hot water storage tank (not shown) and supplied to a predetermined target. The refrigeration cycle device (1) also includes an outdoor unit (OU) installed outside and an indoor unit (IU) installed inside.

[0024] As shown in Figure 1, the refrigeration cycle device (1) comprises a first refrigerant circuit (10), a second refrigerant circuit (20), a refrigerant heat exchanger (30), and a water circuit (40). The first refrigerant circuit (10) is filled with a first refrigerant, and the first refrigerant circulates through it. The second refrigerant circuit (20) is filled with a second refrigerant different from the first refrigerant, and the second refrigerant circulates through it. In this example, the first refrigerant is a flammable or toxic refrigerant. Specifically, the first refrigerant is carbon dioxide, and the second refrigerant is propane (R290). Carbon dioxide is an example of a toxic refrigerant.

[0025] The refrigeration cycle device (1) performs a dual-stage refrigeration cycle. Specifically, a first refrigerant circuit (10) on the lower end and a second refrigerant circuit (20) on the higher end are connected via a refrigerant heat exchanger (30). In this example, the refrigerant heat exchanger (30) has a first flow path (30a) through which the first refrigerant of the first refrigerant circuit (10) flows, and a second flow path (30b) through which the second refrigerant of the second refrigerant circuit (20) flows. In other words, the first refrigerant circuit (10) has the first flow path (30a) of the refrigerant heat exchanger (30), and the second refrigerant circuit (20) has the second flow path (30b) of the refrigerant heat exchanger (30). The refrigerant heat exchanger (30) will be described in detail later.

[0026] [1st refrigerant circuit] The first refrigerant circuit (10) performs a refrigeration cycle using the first refrigerant. In this example, the first refrigerant circuit (10) includes a first compressor (11), a heat source heat exchanger (12), a first expansion valve (13), a first water heat exchanger (14), a first four-way switching valve (15), a receiver (16), and a bridge circuit (50). Near the heat source heat exchanger (12), an outdoor fan (17) is provided to transport outdoor air (an example of heat source air) to the heat source heat exchanger (12) so that the outdoor air passes through the heat source heat exchanger (12). The outdoor fan (17) is an example of a heat source fan that transports heat source air to the heat source heat exchanger (12).

[0027] The first compressor (11), the heat source heat exchanger (12), the first expansion valve (13), the first four-way switching valve (15), the receiver (16), and the bridge circuit (50) are installed in the outdoor unit (OU). The first water heat exchanger (14) is installed in the indoor unit (IU).

[0028] The first compressor (11) compresses the inhaled refrigerant and discharges the compressed refrigerant. For example, the first compressor (11) is a high-pressure dome-type compressor.

[0029] The heat source heat exchanger (12) functions as a heat radiator or evaporator (heat absorber). In this example, the heat source heat exchanger (12) is composed of an air heat exchanger that exchanges heat between "outdoor air transported to the heat source heat exchanger (12) by the outdoor fan (17)" and "first refrigerant flowing through the heat source heat exchanger (12)". The heat source heat exchanger (12) is included in the heat source element component (18).

[0030] The first expansion valve (13) is an example of a pressure reduction mechanism for reducing the pressure of the first refrigerant. In this example, the first expansion valve (13) is comprised of an electrically operated valve whose opening degree can be adjusted.

[0031] The first water heat exchanger (14) exchanges heat between the first refrigerant in the first refrigerant circuit (10) and the water in the water circuit (40). In this example, the first water heat exchanger (14) is composed of a plate-type heat exchanger. Specifically, the first water heat exchanger (14) has a first flow path (14a) through which the first refrigerant in the first refrigerant circuit (10) flows, and a second flow path (14b) through which the water in the water circuit (40) flows, and exchanges heat between the first refrigerant in the first flow path (14a) and the water in the second flow path (14b). The first water heat exchanger (14) functions as a radiator or evaporator. The first water heat exchanger (14) is an example of an auxiliary heat exchanger.

[0032] The receiver (16) stores the first refrigerant and separates it into a gaseous refrigerant and a liquid refrigerant. For example, the receiver (16) is composed of a pressure vessel. The receiver (16) is included in the heat source element component (18).

[0033] The bridge circuit (50) includes a first pipe (51), a second pipe (52), a third pipe (53), a fourth pipe (54), and four check valves (CV). The four check valves (CV) are arranged one-to-one with the four pipes (first to fourth pipes (51 to 54)). The check valves (CV) allow the flow of refrigerant in the direction indicated by the arrows in Figure 1 and prohibit the flow of refrigerant in the opposite direction.

[0034] The outlet end of the first pipe (51) and the outlet end of the second pipe (52) are connected to the inlet side of the receiver (16). The inlet end of the third pipe (53) and the inlet end of the fourth pipe (54) are connected to the outlet side of the receiver (16). The inlet end of the first pipe (51) and the outlet end of the third pipe (53) are connected to the liquid side of the heat source heat exchanger (12). The inlet end of the second pipe (52) and the outlet end of the fourth pipe (54) are connected to the first flow path (30a) of the refrigerant heat exchanger (30).

[0035] In this example, a first expansion valve (13) is located on the outlet side of the receiver (16). The first refrigerant that flows out from the receiver (16) flows through the first expansion valve (13) and then enters the heat source heat exchanger (12) or the refrigerant heat exchanger (30) via the bridge circuit (50). In other words, the first expansion valve (13) is located between the receiver (16) and the heat source heat exchanger (12) and the refrigerant heat exchanger (30). Specifically, in the heating operation described later, the first expansion valve (13) is located between the receiver (16) and the heat source heat exchanger (12), and in the refrigerant recovery operation described later, the first expansion valve (13) is located between the receiver (16) and the refrigerant heat exchanger (30).

[0036] The first four-way switching valve (15) has a first port (P1), a second port (P2), a third port (P3), and a fourth port (P4). The first four-way switching valve (15) is switchable between a first state in which the first port (P1) and the second port (P2) are in communication and the third port (P3) and the fourth port (P4) are in communication, and a second state in which the first port (P1) and the third port (P3) are in communication and the second port (P2) and the fourth port (P4) are in communication.

[0037] In this example, in the first four-way switching valve (15), the first port (P1) is connected to the discharge side of the first compressor (11). The second port (P2) is connected to the gas side of the first water heat exchanger (14). The third port (P3) is connected to the gas side of the heat source heat exchanger (12). The fourth port (P4) is connected to the suction side of the first compressor (11). In addition, the first flow path (30a) of the refrigerant heat exchanger (30) is connected to the liquid side of the first water heat exchanger (14).

[0038] The first four-way switching valve (15) is an example of a first flow path switching mechanism. The first flow path switching mechanism can switch the flow path of the first refrigerant in the first refrigerant circuit (10) between a first flow path state in which the first refrigerant flows sequentially through the first compressor (11), the refrigerant heat exchanger (30), the first expansion valve (13), and the heat source heat exchanger (12), and a second flow path state in which the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12).

[0039] In this example, the first refrigerant circuit (10) includes a first water heat exchanger (14) (auxiliary heat exchanger). In the first flow path state, the first refrigerant flows from the first compressor (11) through the refrigerant heat exchanger (30) and the first water heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) then flows sequentially through the first expansion valve (13) and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows from the first expansion valve (13) through the refrigerant heat exchanger (30) and the first water heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) then flows sequentially through the first compressor (11) and the heat source heat exchanger (12).

[0040] In this example, the heat source component (18) includes a heat source heat exchanger (12) and a receiver (16). In the first flow path state, the first refrigerant flows sequentially from the first compressor (11) to the refrigerant heat exchanger (30), the receiver (16), the first expansion valve (13), and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows sequentially from the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), the heat source heat exchanger (12), and the receiver (16).

[0041] [Second refrigerant circuit] The second refrigerant circuit (20) performs a refrigeration cycle using the second refrigerant. In this example, the second refrigerant circuit (20) includes a second compressor (21), a second water heat exchanger (22), and a second expansion valve (23). The second refrigerant circuit (20) is installed in the indoor unit (IU).

[0042] The second compressor (21) compresses the inhaled refrigerant and discharges the compressed refrigerant. For example, the second compressor (21) is a high-pressure dome-type compressor.

[0043] The second water heat exchanger (22) exchanges heat between the second refrigerant in the second refrigerant circuit (20) and the water in the water circuit (40). In this example, the second water heat exchanger (22) is composed of a plate-type heat exchanger. Specifically, the second water heat exchanger (22) has a first flow path (22a) through which the second refrigerant in the second refrigerant circuit (20) flows, and a second flow path (22b) through which the water in the water circuit (40) flows, and exchanges heat between the second refrigerant in the first flow path (22a) and the water in the second flow path (22b). The second water heat exchanger (22) functions as a radiator or evaporator. The second water heat exchanger (22) is an example of a utilization heat exchanger.

[0044] The second expansion valve (23) is an example of a pressure reduction mechanism for reducing the pressure of the second refrigerant. In this example, the second expansion valve (23) is comprised of an electrically operated valve whose opening degree can be adjusted.

[0045] In this example, the discharge side of the second compressor (21) is connected to the first flow path (22a) of the second water heat exchanger (22), and the suction side of the second compressor (21) is connected to the second flow path (30b) of the refrigerant heat exchanger (30). The first flow path (22a) of the second water heat exchanger (22) is connected to the second flow path (30b) of the refrigerant heat exchanger (30) via the second expansion valve (23).

[0046] [Refrigerant heat exchanger] The refrigerant heat exchanger (30) exchanges heat between the first refrigerant of the first refrigerant circuit (10) and the second refrigerant of the second refrigerant circuit (20). In this example, the refrigerant heat exchanger (30) is composed of a plate-type heat exchanger. Specifically, the refrigerant heat exchanger (30) has a first flow path (30a) through which the first refrigerant of the first refrigerant of the first refrigerant circuit (10) flows, and a second flow path (30b) through which the second refrigerant of the second refrigerant of the second refrigerant circuit (20) flows, and exchanges heat between the first refrigerant of the first flow path (30a) and the second refrigerant of the second flow path (30b).

[0047] Furthermore, the refrigerant heat exchanger (30) functions as either a heat radiator or an evaporator. Specifically, when heat is radiated from the first refrigerant to the second refrigerant in the refrigerant heat exchanger (30), the refrigerant heat exchanger (30) in the first refrigerant circuit (10) functions as a "heat radiator," and the refrigerant heat exchanger (30) in the second refrigerant circuit (20) functions as an "evaporator." Conversely, when heat is radiated from the second refrigerant to the first refrigerant in the refrigerant heat exchanger (30), the refrigerant heat exchanger (30) in the first refrigerant circuit (10) functions as an "evaporator," and the refrigerant heat exchanger (30) in the second refrigerant circuit (20) functions as a "heat radiator."

[0048] [Water circuit] In the water circuit (40), water supplied to a predetermined object is circulated. In this example, the water circuit (40) has a pump (41) for circulating the water. The water circuit (40) is also provided with a hot water storage tank (not shown) for storing heated water. In the water circuit (40), the pump (41), the second flow path (22b) of the second water heat exchanger (22), the second flow path (14b) of the first water heat exchanger (14), and the storage tank are connected in order.

[0049] [Various sensors] Furthermore, the refrigeration cycle device (1) is equipped with various sensors (80), such as pressure sensors and temperature sensors. Examples of physical quantities detected by the various sensors (80) include physical quantities related to the first refrigerant circuit (10), physical quantities related to the second refrigerant circuit (20), and physical quantities related to the water circuit (40). The various information detected by the various sensors (80) is transmitted to the control unit (100), which will be described later.

[0050] Examples of physical quantities relating to the first refrigerant circuit (10) include the pressure and temperature of the high-pressure refrigerant in the first refrigerant circuit (10), the pressure and temperature of the low-pressure refrigerant in the first refrigerant circuit (10), the degree of superheating of the first refrigerant at the outlet of the heat exchanger that functions as an evaporator in the first refrigerant circuit (10), and the temperature of the outdoor air transported to the heat source heat exchanger (12). For example, the high-pressure refrigerant in the first refrigerant circuit (10) is the first refrigerant discharged from the first compressor (11), and the low-pressure refrigerant in the first refrigerant circuit (10) is the first refrigerant drawn into the first compressor (11).

[0051] Examples of physical quantities relating to the second refrigerant circuit (20) include the pressure and temperature of the high-pressure refrigerant in the second refrigerant circuit (20), the pressure and temperature of the low-pressure refrigerant in the second refrigerant circuit (20), and the degree of superheating of the second refrigerant at the outlet of the heat exchanger that functions as an evaporator in the second refrigerant circuit (20). For example, the high-pressure refrigerant in the second refrigerant circuit (20) is the second refrigerant discharged from the second compressor (21), and the low-pressure refrigerant in the second refrigerant circuit (20) is the second refrigerant drawn into the second compressor (21).

[0052] Examples of physical quantities related to the water circuit (40) include the temperature of the water flowing into the second channel (14b) of the first water heat exchanger (14) and the temperature of the water flowing into the second channel (22b) of the second water heat exchanger (22).

[0053] The various sensors (80) described above may be sensors provided to directly detect the physical quantities described above, or sensors provided to indirectly detect or estimate the physical quantities described above.

[0054] [Control Unit] Furthermore, the refrigeration cycle device (1) includes a control unit (100). The control unit (100) includes an MCU (Micro Control Unit), electrical circuits, electronic circuits, etc. The MCU includes a CPU (Central Processing Unit), memory, communication interface, etc. The memory stores various programs for the CPU (processor) to execute. The memory also stores information and data used for controlling the refrigeration cycle device (1) (e.g., setting values ​​such as thresholds), information and data obtained by various sensors (80) (e.g., measured values), and information and data input from outside the refrigeration cycle device (1) (e.g., command values). The control unit (100) may consist of one physically independent element, or it may consist of two or more physically separated elements.

[0055] The control unit (100) controls the first refrigerant circuit (10) and the second refrigerant circuit (20). Specifically, the control unit (100) controls each part of the first refrigerant circuit (10) and the second refrigerant circuit (20) based on various information detected by various sensors (80) and instructions input by the operator of the refrigeration cycle device (1). For example, the operator inputs the desired instructions to the control unit (100) by inputting operations corresponding to the desired instructions to an operation unit (not shown), such as a remote controller. The operation unit transmits a signal corresponding to the operation to the control unit (100).

[0056] In this example, the control unit (100) controls the starting and stopping of the first compressor (11), the rotational speed of the first compressor (11), the opening degree of the first expansion valve (13), the switching of the first four-way switching valve (15), the starting and stopping of the outdoor fan (17), the rotational speed of the outdoor fan (17), the starting and stopping of the second compressor (21), the rotational speed of the second compressor (21), the opening degree of the second expansion valve (23), the starting and stopping of the pump (41), and so on.

[0057] [Heating operation] Next, with reference to Figure 3, the heating operation performed in the refrigeration cycle device (1) will be described. The heating operation is performed to heat the water in the water circuit (40). In the heating operation shown in Figure 3, in the first refrigerant circuit (10), the first water heat exchanger (14) and the refrigerant heat exchanger (30) act as radiators, and the heat source heat exchanger (12) acts as an evaporator. In the second refrigerant circuit (20), the second water heat exchanger (22) acts as a radiator, and the refrigerant heat exchanger (30) acts as an evaporator. In this heating operation, the water in the water circuit (40) is heated in the first water heat exchanger (14) and the second water heat exchanger (22).

[0058] During heating operation, the control unit (100) drives the first refrigerant circuit (10) so that the flow path of the first refrigerant in the first refrigerant circuit (10) enters the first flow path state. The control unit (100) also drives the second refrigerant circuit (20) so that the second refrigerant in the second refrigerant circuit (20) flows sequentially through the second compressor (21), the second water heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30).

[0059] Specifically, during heating operation, the control unit (100) sets the first four-way switching valve (15) to the first state. As a result, the flow path of the first refrigerant in the first refrigerant circuit (10) enters the first flow path state. The control unit (100) also drives the first compressor (11), the outdoor fan (17), the second compressor (21), and the pump (41), and adjusts the opening of the first expansion valve (13) and the opening of the second expansion valve (23) as appropriate.

[0060] In the first refrigerant circuit (10), the first refrigerant flows sequentially through the first compressor (11), the first water heat exchanger (14), the refrigerant heat exchanger (30), the receiver (16), the first expansion valve (13), and the heat source heat exchanger (12).

[0061] Specifically, in the first refrigerant circuit (10), the first refrigerant discharged from the first compressor (11) dissipates heat to the water in the water circuit (40) in the first water heat exchanger (14). This heats the water in the water circuit (40). The first refrigerant that flows out of the first water heat exchanger (14) dissipates heat to the second refrigerant in the second refrigerant circuit (20) in the refrigerant heat exchanger (30). This increases the degree of subcooling of the first refrigerant. The first refrigerant that flows out of the refrigerant heat exchanger (30) passes through the receiver (16), is depressurized in the first expansion valve (13), and evaporates by absorbing heat from the outside air in the heat source heat exchanger (12). The first refrigerant that flows out of the heat source heat exchanger (12) is drawn into the first compressor (11).

[0062] In the second refrigerant circuit (20), the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30).

[0063] Specifically, in the second refrigerant circuit (20), the second refrigerant discharged from the second compressor (21) dissipates heat into the water in the water circuit (40) in the second water heat exchanger (22). This heats the water in the water circuit (40). The second refrigerant that flows out of the second water heat exchanger (22) is depressurized in the second expansion valve (23) and evaporates in the refrigerant heat exchanger (30) by absorbing heat from the first refrigerant in the first refrigerant circuit (10). The refrigerant that flows out of the refrigerant heat exchanger (30) is drawn into the second compressor (21).

[0064] In the water circuit (40), the water transported by the pump (41) flows sequentially through the second water heat exchanger (22) and the first water heat exchanger (14). Specifically, the water discharged from the pump (41) is heated in the second water heat exchanger (22) and the first water heat exchanger (14) and flows into the hot water storage tank. In this way, the water heated in the water circuit (40) is used to generate hot water in the hot water storage tank.

[0065] [Variations of heating operation] In the heating operation described above, the second refrigerant may be prevented from flowing to the second water heat exchanger (22). In this case, in the first refrigerant circuit (10), the first water heat exchanger (14) and the refrigerant heat exchanger (30) become radiators, and the heat source heat exchanger (12) becomes an evaporator. The second refrigerant circuit (20) is stopped. In a modified version of the heating operation, the water in the water circuit (40) is heated in the first water heat exchanger (14), but the water in the water circuit (40) is not heated in the second water heat exchanger (22).

[0066] Specifically, in the modified heating operation, the control unit (100) stops the second compressor (21) and does not adjust the opening of the second expansion valve (23). Other controls in the modified heating operation are the same as those shown in Figure 3.

[0067] [Refrigerant recovery operation] Next, with reference to Figure 4, the refrigerant recovery operation performed in the refrigeration cycle device (1) of Embodiment 1 will be described. The refrigerant recovery operation is performed to recover the first refrigerant from the first refrigerant circuit (10) to the heat source element component (18) after the heating operation is completed. At the end of the heating operation, there is a possibility that the first refrigerant may remain in the refrigerant heat exchanger (30). It is not desirable from a refrigerant management perspective for the first refrigerant to remain in the refrigerant heat exchanger (30) after the operation is completed. Therefore, it is desirable to perform the refrigerant recovery operation after the heating operation is completed.

[0068] In refrigerant recovery operation, the control unit (100) drives the first refrigerant circuit (10) such that the flow path of the first refrigerant in the first refrigerant circuit (10) is switched from the first flow path state to the second flow path state, and the first expansion valve (13) is closed.

[0069] In Embodiment 1, during refrigerant recovery operation, the control unit (100) drives the second refrigerant circuit (20) so that the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22) (utilizing heat exchanger), the second expansion valve (23), and the refrigerant heat exchanger (30). Note that the opening degree of the second expansion valve (23) during refrigerant recovery operation is greater than the opening degree of the second expansion valve (23) during heating operation (for example, the assumed maximum opening degree). For example, the opening degree of the second expansion valve (23) during refrigerant recovery operation is set to fully open.

[0070] Specifically, during refrigerant recovery operation, the control unit (100) switches the first four-way switching valve (15) from the first state to the second state. As a result, the flow path of the first refrigerant in the first refrigerant circuit (10) switches from a "first flow path state in which the first refrigerant flows sequentially through the first compressor (11), the first water heat exchanger (14), the refrigerant heat exchanger (30), the receiver (16), the first expansion valve (13), and the heat source heat exchanger (12)" to a "second flow path state in which the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first water heat exchanger (14), the first compressor (11), and the heat source heat exchanger (12) before reaching the receiver (16).

[0071] Furthermore, during refrigerant recovery operation, the control unit (100) closes the first expansion valve (13) and sets the opening of the second expansion valve (23) to a predetermined degree. The predetermined degree is set to an opening (for example, fully open) that allows the second refrigerant, which has been discharged from the second compressor (21) and passed sequentially through the second water heat exchanger (22) and the second expansion valve (23), to dissipate heat in the refrigerant heat exchanger (30).

[0072] During refrigerant recovery operation, the control unit (100) drives the first compressor (11) and the second compressor (21), and stops the outdoor fan (17) and the pump (41).

[0073] In the first refrigerant circuit (10), when the first expansion valve (13) is closed and the first compressor (11) is driven, a flow of first refrigerant is generated that flows sequentially from the first expansion valve (13) through the refrigerant heat exchanger (30), the first water heat exchanger (14), the first compressor (11), and the heat source heat exchanger (12) to the receiver (16). As a result, the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first water heat exchanger (14), the first compressor (11), and the heat source heat exchanger (12) to the receiver (16). In this way, the first refrigerant from the first refrigerant circuit (10) that remained in the refrigerant heat exchanger (30), etc., is recovered in the receiver (16).

[0074] In the second refrigerant circuit (20), the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22), the second expansion valve (23) maintained at a predetermined opening, and the refrigerant heat exchanger (30). Specifically, the second refrigerant discharged from the second compressor (21) flows sequentially through the second water heat exchanger (22) and the second expansion valve (23) maintained at a predetermined opening (e.g., fully open), and in the refrigerant heat exchanger (30) it dissipates heat to the first refrigerant in the first refrigerant circuit (10). This promotes the evaporation of the first refrigerant in the refrigerant heat exchanger (30).

[0075] [Effects of Embodiment 1] As described above, in the refrigeration cycle device (1) of Embodiment 1, the first flow path switching mechanism (15) can switch the flow path of the first refrigerant in the first refrigerant circuit (10) between a first flow path state in which the first refrigerant flows sequentially through the first compressor (11), the refrigerant heat exchanger (30), the first expansion valve (13), and the heat source heat exchanger (12), and a second flow path state in which the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12).

[0076] During heating operation, the control unit (100) drives the first refrigerant circuit (10) so that the flow path of the first refrigerant in the first refrigerant circuit (10) becomes the first flow path state, and drives the second refrigerant circuit (20) so that the second refrigerant in the second refrigerant circuit (20) flows sequentially through the second compressor (21), the second water heat exchanger (22) (utilizing heat exchanger), the second expansion valve (23), and the refrigerant heat exchanger (30).

[0077] In a refrigerant recovery operation in which the first refrigerant from the first refrigerant circuit (10) is recovered to the heat source element component (18) after the heating operation has finished, the control unit (100) drives the first refrigerant circuit (10) such that the flow path of the first refrigerant in the first refrigerant circuit (10) is switched from the first flow path state to the second flow path state and the first expansion valve (13) is closed.

[0078] In the above configuration, during refrigerant recovery operation, the first refrigerant circuit (10) is driven to change the flow path of the first refrigerant in the first refrigerant circuit (10) to a second flow path state and to close the first expansion valve (13). This generates a flow of first refrigerant that flows sequentially from the first expansion valve (13) through the refrigerant heat exchanger (30) and the first compressor (11) to the heat source heat exchanger (12). As a result, the first refrigerant remaining in the refrigerant heat exchanger (30) and other components can be recovered into the heat source element components (18), including the heat source heat exchanger (12).

[0079] Furthermore, in the refrigeration cycle device (1) of Embodiment 1, the heat source element component (18) includes a heat source heat exchanger (12) and a receiver (16). In the first flow path state, the first refrigerant flows sequentially from the first compressor (11) to the refrigerant heat exchanger (30), the receiver (16), the first expansion valve (13), and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows sequentially from the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), the heat source heat exchanger (12), and the receiver (16).

[0080] In the above configuration, during refrigerant recovery operation, the first refrigerant circuit (10) is driven to change the flow path of the first refrigerant in the first refrigerant circuit (10) to a second flow path state and to close the first expansion valve (13). This generates a flow of first refrigerant that flows sequentially from the first expansion valve (13) through the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12) to the receiver (16). As a result, the first refrigerant remaining in the refrigerant heat exchanger (30), etc., can be recovered into the heat source element component (18), including the heat source heat exchanger (12) and the receiver (16).

[0081] Furthermore, in the refrigeration cycle device (1) of Embodiment 1, the first refrigerant circuit (10) has a first water heat exchanger (14) (auxiliary heat exchanger). In the first flow path state, the first refrigerant flows from the first compressor (11) through the refrigerant heat exchanger (30) and the first water heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) then flows sequentially through the first expansion valve (13) and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows from the first expansion valve (13) through the refrigerant heat exchanger (30) and the first water heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) then flows sequentially through the first compressor (11) and the heat source heat exchanger (12).

[0082] In the above configuration, during refrigerant recovery operation, the first refrigerant circuit (10) is driven to cause the flow path of the first refrigerant in the first refrigerant circuit (10) to become a second flow path state and the first expansion valve (13) to be closed, thereby generating a flow of the first refrigerant in which "the first refrigerant flows from the first expansion valve (13) to the refrigerant heat exchanger (30) and the first water heat exchanger (14) (auxiliary heat exchanger), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) flows through the first compressor (11) and reaches the heat source heat exchanger (12). As a result, the first refrigerant remaining in the refrigerant heat exchanger (30) and the first water heat exchanger (14), etc., can be recovered into the heat source element components (18), including the heat source heat exchanger (12).

[0083] Furthermore, the refrigeration cycle device (1) of Embodiment 1 includes an indoor unit (IU) installed inside the room. The refrigerant heat exchanger (30) and the first water heat exchanger (14) (auxiliary heat exchanger) are housed in the indoor unit (IU).

[0084] In the above configuration, by performing a refrigerant recovery operation after the heating operation is completed, it is possible to prevent the first refrigerant from remaining in the refrigerant heat exchanger (30) and the first water heat exchanger (14) (auxiliary heat exchanger) housed in the indoor unit (IU) installed inside the room. This allows for proper management of the refrigerant in the refrigeration cycle device (1).

[0085] Furthermore, in the refrigeration cycle device (1) of Embodiment 1, the first refrigerant is flammable or toxic.

[0086] In the above configuration, by performing a refrigerant recovery operation after the heating operation is completed, it is possible to prevent flammable or toxic first refrigerants from remaining in the refrigerant heat exchanger (30) or auxiliary heat exchanger (14) housed in the indoor unit (IU) installed inside the room. This allows for safe management of the refrigerant in the refrigeration cycle device (1).

[0087] Furthermore, in the refrigeration cycle device (1) of Embodiment 1, the control unit (100) drives the second refrigerant circuit (20) so that the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22) (utilizing heat exchanger), the second expansion valve (23), and the refrigerant heat exchanger (30) during refrigerant recovery operation. The opening degree of the second expansion valve (23) during refrigerant recovery operation is greater than the opening degree of the second expansion valve (23) during heating operation.

[0088] In the above configuration, by driving the second refrigerant circuit (20) with the opening of the second expansion valve (23) greater than the opening of the second expansion valve (23) during refrigerant recovery operation than during heating operation, the high-temperature, high-pressure second refrigerant discharged from the second compressor (21) can be dissipated to the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30). This promotes the evaporation of the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30), thereby promoting the recovery of the first refrigerant during refrigerant recovery operation.

[0089] (Embodiment 2) Figure 5 illustrates the configuration of the refrigeration cycle device (1) of Embodiment 2. The refrigeration cycle device (1) of Embodiment 2 differs from the refrigeration cycle device (1) of Embodiment 1 in the "configuration of the second refrigerant circuit (20)", "control during heating operation", and "control during refrigerant recovery operation". The other configurations and processes of the refrigeration cycle device (1) of Embodiment 2 are the same as those of the refrigeration cycle device (1) of Embodiment 1.

[0090] The second refrigerant circuit (20) of Embodiment 2 has a second four-way switching valve (24) in addition to the configuration of the second refrigerant circuit (20) of Embodiment 1 shown in Figure 1.

[0091] The second four-way switching valve (24) has a first port (P1), a second port (P2), a third port (P3), and a fourth port (P4). The second four-way switching valve (24) is switchable between a third state in which the first port (P1) and the second port (P2) are in communication and the third port (P3) and the fourth port (P4) are in communication, and a fourth state in which the first port (P1) and the third port (P3) are in communication and the second port (P2) and the fourth port (P4) are in communication (the state shown in Figure 5).

[0092] The second four-way switching valve (24) is an example of a second flow path switching mechanism. The second flow path switching mechanism can switch the flow path of the second refrigerant in the second refrigerant circuit (20) between a third flow path state in which the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22) (utilizing heat exchanger), the second expansion valve (23), and the refrigerant heat exchanger (30), and a fourth flow path state in which the second refrigerant flows sequentially through the second compressor (21), the refrigerant heat exchanger (30), the second expansion valve (23), and the second water heat exchanger (22).

[0093] [Heating operation] In the heating operation of Embodiment 2, the control unit (100) drives the second refrigerant circuit (20) so that the flow path of the second refrigerant in the second refrigerant circuit (20) enters the third flow path state. Specifically, the control unit (100) drives the second refrigerant circuit (20) so that the second four-way switching valve (24) enters the third state (the discharge side of the second compressor (21) is connected to the second water heat exchanger (22)).

[0094] The control of the second refrigerant circuit (20) in the heating operation of Embodiment 2 (control of the second compressor (21) and the second expansion valve (23)) is the same as the control of the second refrigerant circuit (20) in the heating operation of Embodiment 1. The flow and state changes (heat dissipation and heat absorption) of the second refrigerant in the second refrigerant circuit (20) in the heating operation of Embodiment 2 are the same as the flow and state changes of the second refrigerant in the second refrigerant circuit (20) in the heating operation of Embodiment 1.

[0095] [Refrigerant recovery operation] Next, with reference to Figure 5, the refrigerant recovery operation of Embodiment 2 will be described. The refrigerant recovery operation of Embodiment 2 differs from that of Embodiment 1 in the control of the second refrigerant circuit (20). Other controls of the refrigerant recovery operation of Embodiment 2 (such as the control of the first refrigerant circuit (10)) are the same as those of the refrigerant recovery operation of Embodiment 1.

[0096] In the refrigerant recovery operation of Embodiment 2, the control unit (100) drives the second refrigerant circuit (20) so that the flow path of the second refrigerant in the second refrigerant circuit (20) is switched from the third flow path state to the fourth flow path state.

[0097] Specifically, in the refrigerant recovery operation of Embodiment 2, the control unit (100) switches the second four-way switching valve (24) from the third state to the fourth state. As a result, the flow path of the second refrigerant in the second refrigerant circuit (20) switches from "the third flow path state in which the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22) (utilizing heat exchanger), the second expansion valve (23), and the refrigerant heat exchanger (30)" to "the fourth flow path state in which the second refrigerant flows sequentially through the second compressor (21), the refrigerant heat exchanger (30), the second expansion valve (23), and the second water heat exchanger (22)". The control unit (100) also drives the second compressor (21) and adjusts the opening degree of the second expansion valve (23) as appropriate.

[0098] In the second refrigerant circuit (20), the second refrigerant discharged from the second compressor (21) dissipates heat to the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30). This promotes the evaporation of the first refrigerant in the refrigerant heat exchanger (30). The second refrigerant that flows out of the refrigerant heat exchanger (30) is depressurized in the second expansion valve (23) and absorbs heat from the water in the water circuit (40) in the second water heat exchanger (22). The second refrigerant that flows out of the second water heat exchanger (22) is drawn into the second compressor (21).

[0099] [Effects of Embodiment 2] The refrigeration cycle device (1) of Embodiment 2 can obtain the same effects as the refrigeration cycle device (1) of Embodiment 1. For example, the first refrigerant remaining in the refrigerant heat exchanger (30) and the like can be recovered into the heat source element component (18), including the heat source heat exchanger (12).

[0100] Furthermore, in the refrigeration cycle device (1) of Embodiment 2, the second refrigerant circuit (20) has a second four-way switching valve (24) (second flow path switching mechanism). The second four-way switching valve (24) can switch the flow path of the second refrigerant in the second refrigerant circuit (20) between a third flow path state in which the second refrigerant flows sequentially through the second compressor (21), the second water heat exchanger (22) (utilizing heat exchanger), the second expansion valve (23), and the refrigerant heat exchanger (30), and a fourth flow path state in which the second refrigerant flows sequentially through the second compressor (21), the refrigerant heat exchanger (30), the second expansion valve (23), and the second water heat exchanger (22).

[0101] During heating operation, the control unit (100) drives the second refrigerant circuit (20) so that the flow path of the second refrigerant in the second refrigerant circuit (20) becomes the third flow path state. During refrigerant recovery operation, the control unit (100) drives the second refrigerant circuit (20) so that the flow path of the second refrigerant in the second refrigerant circuit (20) switches from the third flow path state to the fourth flow path state.

[0102] In the above configuration, during refrigerant recovery operation, the second refrigerant circuit (20) is driven so that the flow path of the second refrigerant in the second refrigerant circuit (20) becomes a fourth flow path state, thereby allowing the second refrigerant in the second refrigerant circuit (20) to be released to the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30). This promotes the evaporation of the first refrigerant in the first refrigerant circuit (10) in the refrigerant heat exchanger (30), thereby promoting the recovery of the first refrigerant during refrigerant recovery operation.

[0103] (Other embodiments) The above explanation may be structured as follows:

[0104] As an example of the first flow path switching mechanism, a "first four-way switching valve (15)" was given, but the mechanism is not limited to this. For example, the first flow path switching mechanism may be composed of two three-way valves, or of other combinations of valves.

[0105] As an example of a second flow path switching mechanism, a "second four-way switching valve (24)" was given, but the mechanism is not limited to this. For example, the second flow path switching mechanism may be composed of two three-way valves, or of other combinations of valves.

[0106] While a "first water heat exchanger (14)" was given as an example of an auxiliary heat exchanger, the invention is not limited to this. For example, the utilization heat exchanger may be composed of an air heat exchanger that exchanges heat between the first refrigerant of the first refrigerant circuit (10) and air (utilizing air such as indoor air).

[0107] While a "second water heat exchanger (22)" was given as an example of a heat exchanger, the invention is not limited to this. For example, the heat exchanger may be composed of an air heat exchanger that exchanges heat between the second refrigerant of the second refrigerant circuit (20) and air (e.g., usable air such as indoor air).

[0108] In the first refrigerant circuit (10), the first water heat exchanger (14) may be connected in series with the refrigerant heat exchanger (30), or it may be connected in parallel with the refrigerant heat exchanger (30). The first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) may be the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first water heat exchanger (14) in sequence, or it may be the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the first refrigerant that has flowed through the first water heat exchanger (14) merged together.

[0109] The refrigeration cycle device (1) does not necessarily have to include a receiver (16) and a bridge circuit (50). In this case, the first expansion valve (13) may be located between the heat source heat exchanger (12) and the refrigerant heat exchanger (30).

[0110] The refrigeration cycle device (1) does not necessarily have to include a first water heat exchanger (14). In this case, the second port (P2) of the first four-way switching valve (15) may be connected to a refrigerant heat exchanger (30).

[0111] Furthermore, while embodiments and modifications have been described, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Also, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate. Moreover, the designations "first," "second," "third," etc., in the specification and claims are used to distinguish the phrases to which these designations are given, and do not limit the number or order of such phrases. [Industrial applicability]

[0112] As described above, this disclosure is useful as a refrigeration cycle device. [Explanation of Symbols]

[0113] 1. Refrigeration cycle system 10 1st refrigerant circuit 11. First Compressor 12 Heat source heat exchanger 13. First expansion valve 14 1st water heat exchanger (auxiliary heat exchanger) 15. First four-way switching valve (first flow path switching mechanism) 16 Receivers 17 Outdoor fan 20 Second refrigerant circuit 21. Second Compressor 22 2nd water heat exchanger (utilized heat exchanger) 23. Second expansion valve 24. Second four-way switching valve (second flow path switching mechanism) 30 Refrigerant heat exchanger 40 water circuit 41 pumps 50 Bridge Circuits 100 Control Unit

Claims

1. A first refrigerant circuit (10) through which the first refrigerant circulates, A second refrigerant circuit (20) through which the second refrigerant circulates, A refrigerant heat exchanger (30) that exchanges heat between the first refrigerant in the first refrigerant circuit (10) and the second refrigerant in the second refrigerant circuit (20), The system comprises a control unit (100) that controls the first refrigerant circuit (10) and the second refrigerant circuit (20), The first refrigerant circuit (10) includes a first compressor (11), a heat source element component (18) including a heat source heat exchanger (12), a first expansion valve (13), and a first flow path switching mechanism (15). The second refrigerant circuit (20) comprises a second compressor (21), a heat exchanger (22), and a second expansion valve (23). The first expansion valve (13) is positioned between the heat source element component (18) and the refrigerant heat exchanger (30) in the first refrigerant circuit (10). The first flow path switching mechanism (15) is capable of switching the flow path of the first refrigerant in the first refrigerant circuit (10) between a first flow path state in which the first refrigerant flows sequentially through the first compressor (11), the refrigerant heat exchanger (30), the first expansion valve (13), and the heat source heat exchanger (12), and a second flow path state in which the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), and the heat source heat exchanger (12). The control unit (100) In heating operation, the first refrigerant circuit (10) is driven so that the flow path of the first refrigerant in the first refrigerant circuit (10) becomes the first flow path state, and the second refrigerant circuit (20) is driven so that the second refrigerant in the second refrigerant circuit (20) flows sequentially through the second compressor (21), the utilization heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30). In a refrigerant recovery operation in which the first refrigerant from the first refrigerant circuit (10) is recovered into the heat source component (18) after the completion of the heating operation, the first refrigerant circuit (10) is driven such that the flow path of the first refrigerant in the first refrigerant circuit (10) is switched from the first flow path state to the second flow path state, and the first expansion valve (13) is closed. Refrigeration cycle device.

2. In the refrigeration cycle apparatus of claim 1, The second refrigerant circuit (20) has a second flow path switching mechanism (24), The second flow path switching mechanism (24) is capable of switching the flow path of the second refrigerant in the second refrigerant circuit (20) between a third flow path state in which the second refrigerant flows sequentially through the second compressor (21), the utilization heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30), and a fourth flow path state in which the second refrigerant flows sequentially through the second compressor (21), the refrigerant heat exchanger (30), the second expansion valve (23), and the utilization heat exchanger (22). The control unit (100) In the heating operation, the second refrigerant circuit (20) is driven so that the flow path of the second refrigerant in the second refrigerant circuit (20) becomes the third flow path state. In the refrigerant recovery operation, the second refrigerant circuit (20) is driven so that the flow path of the second refrigerant in the second refrigerant circuit (20) is switched from the third flow path state to the fourth flow path state. Refrigeration cycle device.

3. In the refrigeration cycle apparatus of claim 1, The control unit (100) drives the second refrigerant circuit (20) so that the second refrigerant flows sequentially through the second compressor (21), the utilization heat exchanger (22), the second expansion valve (23), and the refrigerant heat exchanger (30) during the refrigerant recovery operation. The opening of the second expansion valve (23) in the refrigerant recovery operation is greater than the opening of the second expansion valve (23) in the heating operation. Refrigeration cycle device.

4. In the refrigeration cycle apparatus of claim 1, The heat source element component (18) includes the heat source heat exchanger (12) and the receiver (16), In the first flow path state, the first refrigerant flows sequentially from the first compressor (11) to the refrigerant heat exchanger (30), the receiver (16), the first expansion valve (13), and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows sequentially through the first expansion valve (13), the refrigerant heat exchanger (30), the first compressor (11), the heat source heat exchanger (12), and the receiver (16). Refrigeration cycle device.

5. In the refrigeration cycle apparatus of claim 1, The first refrigerant circuit (10) has an auxiliary heat exchanger (14), In the first flow path state, the first refrigerant flows from the first compressor (11) through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) then flows sequentially through the first expansion valve (13) and the heat source heat exchanger (12). In the second flow path state, the first refrigerant flows from the first expansion valve (13) through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14), and the first refrigerant that has flowed through the refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) then flows sequentially through the first compressor (11) and the heat source heat exchanger (12). Refrigeration cycle device.

6. In the refrigeration cycle apparatus of claim 1, It is equipped with an indoor unit (IU) installed inside the room, The refrigerant heat exchanger (30) is housed in the indoor unit (IU). Refrigeration cycle device.

7. In the refrigeration cycle apparatus of claim 5, It is equipped with an indoor unit (IU) installed inside the room, The refrigerant heat exchanger (30) and the auxiliary heat exchanger (14) are housed in the indoor unit (IU). Refrigeration cycle device.

8. In the refrigeration cycle apparatus of claim 6 or 7, The first refrigerant is flammable or toxic. Refrigeration cycle device.

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