Refrigeration cycle device

Abstract

This refrigeration cycle device comprises a heat source machine, an auxiliary heat source machine, and a load device. The heat source machine, the auxiliary heat source machine, and the load device are connected by a plurality of pipes through which a refrigerant flows. The heat source machine includes a compressor that compresses the refrigerant, and a heat source-side heat exchanger that exchanges heat between the refrigerant and a first fluid. The auxiliary heat source machine has an auxiliary heat exchanger that exchanges heat between the refrigerant and a second fluid that has heat derived from renewable energy or waste heat and that is thermally independent from the first fluid. The load device has a load-side heat exchanger that exchanges heat between the refrigerant and a third fluid that is to be heated or cooled. The refrigeration cycle device has a bypass pipe that bypasses the one of the auxiliary heat exchanger and the load-side heat exchanger that acts as an evaporator, a bypass-side throttle device that is provided in the bypass pipe and reduces the pressure of the refrigerant, and a control device that controls the bypass-side throttle device. The control device opens the bypass-side throttle device such that a portion of the refrigerant flowing toward the auxiliary heat exchanger or the load-side heat exchanger that acts as the evaporator passes through the bypass pipe.

Description

Refrigeration cycle equipment

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

[0002] Due to increasing social demands for ZEB (Zero Energy Based) and carbon neutrality, air conditioners that utilize unused heat such as geothermal heat or solar heat in addition to conventional air heat sources have been proposed (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2017-203573

[0004] However, when a heat source that uses unused heat is connected to the refrigerant circuit of a large-sized air conditioner, differences in the refrigerant phase state can increase the pressure loss of the refrigerant, and differences in the heat exchanger volume can cause an excess or deficiency of the refrigerant amount. As a result, the energy-saving performance of the air conditioner described in Patent Document 1 can be reduced.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a refrigeration cycle device that suppresses a decrease in energy-saving performance.

[0006] The refrigeration cycle apparatus according to the present disclosure includes a heat source unit, an auxiliary heat source unit, and a load device, and the heat source unit, auxiliary heat source unit, and load device are connected by a plurality of pipes through which a refrigerant flows. The heat source unit has a compressor that compresses the refrigerant, and a heat source side heat exchanger that performs heat exchange between the refrigerant and a first fluid. The auxiliary heat source unit has an auxiliary heat exchanger that performs heat exchange between the refrigerant and a second fluid that is thermally independent of the first fluid and that has heat derived from renewable energy or waste heat. The load device has a load side heat exchanger that performs heat exchange between the refrigerant and a third fluid that is an object to be heated or cooled. The refrigeration cycle apparatus includes a bypass pipe that bypasses either the auxiliary heat exchanger or the load side heat exchanger that functions as an evaporator, a bypass side throttling device that is provided in the bypass pipe and that decompresses the refrigerant, and a control device that controls the bypass side throttling device. The control device opens the bypass side throttling device so that a portion of the refrigerant flowing toward the auxiliary heat exchanger or the load side heat exchanger that functions as an evaporator passes through the bypass pipe.

[0007] According to the refrigeration cycle apparatus of the present disclosure, a throttle device provided in the bypass piping is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger or the load-side heat exchanger acting as an evaporator passes through the bypass piping. Therefore, excess refrigerant generated due to the volume difference between the heat source-side heat exchanger and the auxiliary heat exchanger flows to the heat source unit without passing through the evaporator. This reduces the proportion of gas-phase refrigerant, which has a lower density than liquid-phase refrigerant and two-phase gas-liquid refrigerant, in the piping between the auxiliary heat source unit or the load unit and the heat source unit. This reduces the degradation of the energy-saving performance of the refrigeration cycle apparatus.

[0008] 1 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to embodiment 1. FIG. 2 is a hardware configuration diagram showing a control device according to embodiment 1. FIG. 3 is a hardware configuration diagram showing a control device according to embodiment 1. FIG. 4 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 1. FIG. 5 is a flowchart showing the operation of the control device according to embodiment 1. FIG. 6 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of a refrigeration cycle apparatus according to embodiment 1. FIG. 7 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to embodiment 2. FIG. 8 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 2. FIG. 9 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of a refrigeration cycle apparatus according to embodiment 2. FIG. 10 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to embodiment 3. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of a refrigeration cycle apparatus according to embodiment 3. FIG. 12 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to embodiment 4. FIG. 13 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 4. FIG. 14 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of a refrigeration cycle apparatus according to embodiment 4. FIG. 15 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to embodiment 5. FIG. 16 is a refrigerant circuit diagram showing a refrigerant circuit of a refrigeration cycle Fig. 1 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 6. Fig. 2 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to embodiment 7. Fig. 3 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 7. Fig. 4 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of a refrigeration cycle apparatus according to embodiment 7. Fig. 5 is a refrigerant circuit diagram showing a refrigeration cycle apparatus according to embodiment 8. Fig. 6 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 8. Fig. 7 is a refrigerant circuit diagram showing a refrigeration cycle apparatus according to a modified example of embodiment 8. Fig. 8 is a refrigerant circuit diagram showing a refrigeration cycle apparatus according to embodiment 9. Fig. 9 is a functional block diagram of a refrigeration cycle apparatus according to embodiment 9.

[0009] Hereinafter, a refrigeration cycle apparatus according to an embodiment of the present disclosure will be described with reference to the drawings. Hereinafter, in the drawings, the same reference numerals are used to denote the same or equivalent components, and these components are common throughout the embodiments described below. Furthermore, the configurations of the components shown throughout the specification are merely examples, and are not intended to be limiting to the configurations described in the specification.

[0010] Embodiment 1. FIG. 1 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus according to Embodiment 1. The refrigeration cycle apparatus 1 of Embodiment 1 is an air conditioning apparatus that conditions a space to be air-conditioned, such as a room. The following description will be given using an example in which the refrigeration cycle apparatus 1 is an air conditioning apparatus capable of performing at least cooling and heating operation modes. However, the refrigeration cycle apparatus 1 may also be a refrigerator, freezer, or vending machine that cools stored items. The refrigeration cycle apparatus 1 may also be a refrigeration apparatus installed in a showcase or the like. Furthermore, the refrigeration cycle apparatus 1 may also be a water heater that supplies hot water or a chiller that supplies cold water. As shown in FIG. 1 , the refrigeration cycle apparatus 1 includes a heat source unit 2, a load unit 3, a relay unit 4, and an auxiliary heat source unit 7. The heat source unit 2 and the relay unit 4 are connected by connecting pipes 801 and 802. The load unit 3 and the relay unit 4 are connected by connecting pipes 803 and 804. The auxiliary heat source unit 7 and the relay unit 4 are connected by connecting pipes 805 and 806. A refrigerant circulates through the devices and pipes of the heat source unit 2, the load unit 3, the relay unit 4, and the auxiliary heat source unit 7, as well as the connecting pipes 801 to 806. The refrigeration cycle device 1 may be capable of performing an operation mode other than the cooling operation and the heating operation, such as a dehumidifying operation.

[0011] The heat source unit 2 is, for example, an outdoor unit installed outdoors. The heat source unit 2 is equipment that supplies hot or cold heat to the load device 3. The heat source unit 2 has heat source-side piping 201. The heat source unit 2 also has a compressor 21, a flow path switching device 22, a heat source-side heat exchanger 23, and a heat source-side blower 24.

[0012] The heat source side piping 201 is a piping provided inside a housing (not shown) of the heat source unit 2, and has one end connected to a connection piping 801 and the other end connected to a connection piping 802. The heat source side piping 201 connects the compressor 21, the flow path switching device 22, and the heat source side heat exchanger 23. A refrigerant flows inside the heat source side piping 201.

[0013] The compressor 21 draws in a refrigerant in a low-temperature and low-pressure state, compresses the drawn-in refrigerant using an internal compressor 21 mechanism, and discharges the refrigerant in a high-temperature and high-pressure state. The refrigerant compressed by the compressor 21 is discharged and sent to the flow path switching device 22. As the compressor 21, for example, a rotary compressor, a scroll compressor, a screw compressor, a reciprocating compressor, or the like is used.

[0014] The flow path switching device 22 switches the flow direction of the refrigerant in the refrigerant circuit and is, for example, a four-way valve. When the refrigeration cycle apparatus 1 performs cooling operation, the flow path switching device 22 connects the discharge side of the compressor 21 to the heat source side heat exchanger 23. When the refrigeration cycle apparatus 1 performs heating operation, the flow path switching device 22 connects the suction side of the compressor 21 to the heat source side heat exchanger 23. If the refrigeration cycle apparatus 1 is an apparatus that performs only cooling operation or heating operation, the flow path switching device 22 may be omitted.

[0015] The heat source-side heat exchanger 23 exchanges heat between the refrigerant flowing into it and the outdoor air OA. During cooling operation, the heat source-side heat exchanger 23 functions as a condenser, exchanging heat between the refrigerant and the outdoor air OA to condense and liquefy the refrigerant. During heating operation, the heat source-side heat exchanger 23 functions as an evaporator, exchanging heat between the refrigerant and the outdoor air OA to evaporate the refrigerant. Examples of the heat source-side heat exchanger 23 include a fin-and-tube heat exchanger, a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, a double-pipe heat exchanger, and a plate-type heat exchanger. The outdoor air OA is a renewable energy source. Renewable energy refers to energy that is naturally replenished at a rate greater than its utilization. The heat source-side heat exchanger 23 may also exchange heat between the refrigerant and another fluid, such as water, instead of the outdoor air OA. In the heat source side heat exchanger 23, the fluid that exchanges heat with the refrigerant corresponds to the "first fluid" in the present disclosure.

[0016] The heat source-side blower 24 is a device that sends outdoor air OA to the heat source-side heat exchanger 23. The heat source-side blower 24 is disposed adjacent to the heat source-side heat exchanger 23. Sending the outdoor air OA from the heat source-side blower 24 improves the efficiency of heat exchange between the refrigerant and the outdoor air OA. The heat source-side blower 24 may be a propeller fan, a line flow fan (registered trademark), or a multi-blade centrifugal fan. The type and specifications of the heat source-side blower 24 are determined based on operating conditions such as the type, flow rate, and static pressure of the fluid that performs heat exchange. Note that if the heat source-side heat exchanger 23 exchanges heat between a fluid such as water and a refrigerant, a pump that circulates water or the like may be used instead of the heat source-side blower 24.

[0017] The load device 3 is, for example, an indoor unit installed indoors. The load device 3 receives cold or hot heat via refrigerant from the heat source device 2 and the auxiliary heat source device 7 to perform air conditioning in the room. The load device 3 has load-side piping 301. The load device 3 also has a load-side heat exchanger 31, a load-side throttle device 32, and a load-side fan 33.

[0018] The load-side pipe 301 is a pipe provided inside a housing (not shown) of the load device 3, and has one end connected to the connection pipe 803 and the other end connected to the connection pipe 804. The load-side pipe 301 connects the load-side heat exchanger 31 and the load-side throttle device 32. A refrigerant flows inside the load-side pipe 301.

[0019] The load-side heat exchanger 31 exchanges heat between the refrigerant flowing therein and the indoor air. During cooling operation, the load-side heat exchanger 31 functions as an evaporator, exchanging heat between the refrigerant and the indoor air to evaporate the refrigerant. During heating operation, the load-side heat exchanger 31 functions as a condenser, exchanging heat between the refrigerant and the indoor air to condense the refrigerant. Examples of the load-side heat exchanger 31 include a fin-and-tube heat exchanger, a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, a double-pipe heat exchanger, and a plate heat exchanger. If the refrigeration cycle apparatus 1 is, for example, a chiller, the load-side heat exchanger 31 may exchange heat between the refrigerant and water to supply chilled water. If the refrigeration cycle apparatus 1 is, for example, a water heater, the load-side heat exchanger 31 may exchange heat between the refrigerant and water to supply hot water. In the load-side heat exchanger 31, the fluid that exchanges heat with the refrigerant corresponds to the "third fluid" in the present disclosure.

[0020] When the refrigeration cycle apparatus 1, which is an air conditioner, performs cooling operation, the air in the air-conditioned space where the load device 3 is installed is the "object to be cooled" in the present disclosure, and when the refrigeration cycle apparatus 1, which is a chiller, supplies cold water, the water flowing through the load-side heat exchanger 31 is the "object to be cooled" in the present disclosure. Similarly, when the refrigeration cycle apparatus 1, which is an air conditioner, performs heating operation, the air in the air-conditioned space where the load device 3 is installed is the "object to be heated" in the present disclosure, and when the refrigeration cycle apparatus 1, which is a water heater, supplies hot water, the water flowing through the load-side heat exchanger 31 is the "object to be heated" in the present disclosure.

[0021] The load-side blower 33 is a device that sends indoor air to the load-side heat exchanger 31. The load-side blower 33 is disposed adjacent to the load-side heat exchanger 31. By sending indoor air from the load-side blower 33, the efficiency of heat exchange between the refrigerant and the indoor air is improved. The load-side blower 33 may be a propeller fan, a line flow fan (registered trademark), or a multi-blade centrifugal fan. The type and specifications of the load-side blower 33 are determined based on operating conditions such as the type, flow rate, and static pressure of the fluid that performs heat exchange. Note that if the load-side heat exchanger 31 exchanges heat between a fluid such as water and a refrigerant, a pump that circulates water or the like may be used instead of the load-side blower 33.

[0022] The load-side expansion device 32 reduces the pressure of the refrigerant flowing through the load-side pipe 301 to expand it, and is, for example, an electric expansion valve whose opening can be changed to adjust the flow rate of the refrigerant. Note that the load-side expansion device 32 is not limited to an electric expansion valve, and may be a mechanical expansion valve that uses a diaphragm in the pressure-receiving section. The load-side expansion device 32 may also be configured using a capillary tube or the like.

[0023] The relay unit 4 is a device that relays the flow of refrigerant between the heat source unit 2, the load device 3, and the auxiliary heat source unit 7. The relay unit 4 has relay pipes 401 to 403, a first bypass pipe 501, and a second bypass pipe 502. The relay unit 4 also has a first bypass-side throttle device 51, a second bypass-side throttle device 52, and an on-off valve 40 and an on-off valve 41.

[0024] The relay pipe 401 is a pipe provided inside the housing (not shown) of the relay unit 4, and has one end connected to the connection pipe 801 and the other end connected to the connection pipe 803. The relay pipe 402 is a pipe provided inside the housing of the relay unit 4, and has one end connected to the connection pipe 804 and the other end connected to the connection pipe 805. The relay pipe 403 is a pipe provided inside the housing of the relay unit 4, and has one end connected to the connection pipe 806 and the other end connected to the connection pipe 802.

[0025] The first bypass pipe 501 is a pipe provided inside the housing of the relay unit 4, and has one end connected to the relay pipe 401 and the other end connected to the relay pipe 402. A portion where the first bypass pipe 501 connects to the relay pipe 401 is referred to as a branch portion 601. A portion where the first bypass pipe 501 connects to the relay pipe 402 is referred to as a branch portion 602. When the refrigeration cycle apparatus 1 performs cooling operation, a portion of the refrigerant flowing through the relay pipe 402 does not flow through the load side heat exchanger 31 acting as an evaporator, but flows through the first bypass pipe 501 via the branch portion 602. In other words, a portion of the refrigerant flowing toward the load side heat exchanger 31 acting as an evaporator bypasses the load side heat exchanger 31.

[0026] The second bypass pipe 502 is a pipe provided inside the housing of the relay unit 4, and has one end connected to the relay pipe 402 and the other end connected to the relay pipe 403. A portion where the second bypass pipe 502 connects to the relay pipe 402 is referred to as a branch portion 603. A portion where the second bypass pipe 502 connects to the relay pipe 403 is referred to as a branch portion 604. When the refrigeration cycle apparatus 1 performs heating operation, a portion of the refrigerant flowing through the relay pipe 402 does not flow through the auxiliary heat exchanger 72 acting as an evaporator, but flows through the second bypass pipe 502 via the branch portion 603. In other words, a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator bypasses the auxiliary heat exchanger 72.

[0027] The first bypass-side throttle device 51 is provided in the first bypass pipe 501 and reduces the pressure of the refrigerant flowing through the first bypass pipe 501 to expand it. For example, it is an electric expansion valve whose opening can be changed to adjust the refrigerant flow rate. The second bypass-side throttle device 52 is provided in the second bypass pipe 502 and reduces the pressure of the refrigerant flowing through the second bypass pipe 502 to expand it. For example, it is an electric expansion valve whose opening can be changed to adjust the refrigerant flow rate. Note that the first bypass-side throttle device 51 and the second bypass-side throttle device 52 are not limited to electric expansion valves and may be mechanical expansion valves that employ diaphragms in their pressure-receiving portions. Furthermore, the first bypass-side throttle device 51 and the second bypass-side throttle device 52 may be configured using capillary tubes or the like.

[0028] During cooling operation, the first bypass piping 501 connects the relay piping 402 through which the refrigerant flows from the auxiliary heat exchanger 72 to the load-side heat exchanger 31, and the relay piping 401 through which the refrigerant flows from the load-side heat exchanger 31 to the heat-source-side heat exchanger 23. Therefore, during cooling operation, the first bypass piping 501 and the first bypass-side throttle device 51 correspond to the "bypass piping" and the "bypass-side throttle device" in the present disclosure. During heating operation, the second bypass piping 502 connects the relay piping 402 through which the refrigerant flows from the load-side heat exchanger 31 to the auxiliary heat exchanger 72, and the relay piping 403 through which the refrigerant flows from the auxiliary heat exchanger 72 to the heat-source-side heat exchanger 23. Therefore, during heating operation, the second bypass piping 502 and the second bypass-side throttle device 52 correspond to the "bypass piping" and the "bypass-side throttle device" in the present disclosure.

[0029] The on-off valve 40 is a valve provided in the relay pipe 402. The on-off valve 40 switches between an open state in which the refrigerant flows through the relay pipe 402 and a closed state in which the refrigerant flows through the relay pipe 402. The on-off valve 41 is a valve provided in the relay pipe 403. The on-off valve 41 switches between an open state in which the refrigerant flows through the relay pipe 403 and a closed state in which the refrigerant flows through the relay pipe 403.

[0030] The auxiliary heat source unit 7 is a device that supplies hot or cold heat to the load device 3. As will be described in detail later, the auxiliary heat source unit 7 uses renewable energy or so-called unused heat such as waste heat as a heat source, and has an auxiliary function to the heat source unit 2. The auxiliary heat source unit 7 has auxiliary heat source side piping 701. The auxiliary heat source unit 7 also has an auxiliary side throttle device 71 and an auxiliary heat exchanger 72.

[0031] The auxiliary heat source side pipe 701 is a pipe provided inside the housing (not shown) of the auxiliary heat source unit 7 , and one end is connected to the connection pipe 805 and the other end is connected to the connection pipe 806 .

[0032] The auxiliary heat exchanger 72 exchanges heat between the refrigerant and the heat medium. The auxiliary heat exchanger 72 has a refrigerant flow path 721 through which the refrigerant flows and a heat medium flow path 722 through which the heat medium flows. The refrigerant flow path 721 is a flow path through which the refrigerant flows through the auxiliary heat source side piping 701. The compressor 21, flow path switching device 22, and heat source side heat exchanger 23 of the heat source unit 2, the load side heat exchanger 31 and load side expansion device 32 of the load unit 3, and the refrigerant flow path 721 and auxiliary side expansion device 71 of the auxiliary heat exchanger 72 of the auxiliary heat source unit 7 are connected by connection piping 801 to 806, the heat source side piping 201, the load side piping 301, the relay piping 401 to 403, and the auxiliary heat source side piping 701, thereby forming a refrigerant circuit.

[0033] The refrigerant may be a fluid that undergoes latent heat change, such as a single refrigerant such as R1234yf, R1234ze, R32, or R290, or a mixed refrigerant containing two or more of these. Also, a mixed refrigerant containing one of the above single refrigerants and another refrigerant, a mixed refrigerant containing R1132(E), or a mixed refrigerant containing R1123 may be used. Also, a mixed refrigerant containing R516A, R445A, R444A, R454C, R444B, R454A, R455A, R457A, R459B, R452B, R454B, R447B, R447A, R446A, R459A, R474A, or R479A may be used.

[0034] The heat medium flow path 722 is connected to a tank 92 that stores the heat medium by a heat medium pipe 901. The heat medium is supplied to the heat medium flow path 722 from the tank 92 via the heat medium pipe 901. A water circuit is formed by connecting the tank 92 and the heat medium flow path 722 of the auxiliary heat exchanger 72 by the heat medium pipe 901. The auxiliary heat exchanger 72 is provided with a water pump 91 that circulates the heat medium through the water circuit.

[0035] It is desirable that the temperature of the heat medium circulating through the water circuit be stable throughout the year. In particular, it is desirable that the heat medium be at a lower temperature than the outdoor air during cooling operation and at a higher temperature than the outdoor air during heating operation. The auxiliary heat exchanger 72 acts as a condenser during cooling operation, exchanging heat between the refrigerant flowing through the refrigerant flow path 721 and the heat medium flowing through the heat medium flow path 722 to condense and liquefy the refrigerant. The auxiliary heat exchanger 72 acts as an evaporator during heating operation, exchanging heat between the refrigerant flowing therein and the heat medium to evaporate the refrigerant. The auxiliary heat exchanger 72 is, for example, a plate-type heat exchanger.

[0036] The heat medium stored in the tank 92 is, for example, well water. The well water contains geothermal heat, which is renewable energy contained in the earth S. In other words, the well water is a fluid that has heat derived from geothermal heat, and the auxiliary heat exchanger 72 uses the geothermal heat contained in the well water as its heat source. Solar heat may also be used as the heat source. When solar heat is used as the heat source for the auxiliary heat exchanger 72, the heat medium heated by solar panels or the like is stored in the tank 92. Specific examples of the heat medium in this case include a calcium chloride aqueous solution, a sodium chloride aqueous solution, a magnesium chloride aqueous solution, brine containing ethylene glycol, antifreeze, or a fluid that undergoes latent heat change, such as water. In this way, renewable energy is used as the heat source for the auxiliary heat exchanger 72. However, instead of circulating well water directly through the auxiliary heat exchanger 72, a heat exchanger may be provided in the tank 92 to exchange heat between the well water and a heat medium such as a calcium chloride aqueous solution, a sodium chloride aqueous solution, a magnesium chloride aqueous solution, brine containing ethylene glycol, antifreeze, or water, and the heat-exchanged heat medium may be circulated through the water circuit.

[0037] Furthermore, as the heat medium for the auxiliary heat exchanger 72, a heat medium containing waste heat other than renewable energy may be used as long as it is continuously supplied. For example, wastewater from the facility in which the refrigeration cycle device 1 is installed may be stored in a tank 92, and a heat exchanger may be provided in the tank 92 to exchange heat between the heat medium flowing through the auxiliary heat exchanger 72 and the wastewater stored in the tank 92, and the heat-exchanged heat medium may be circulated through the water circuit. Furthermore, the auxiliary heat exchanger 72 may be disposed in a heat exhaust duct of the facility in which the refrigeration cycle device 1 is installed, and heat may be exchanged between the air in the heat exhaust duct and the heat medium. The heat source utilized by the auxiliary heat source unit 7 is limited to one that is not thermally affected by the fluid that exchanges heat with the refrigerant in the heat source unit 2. For this reason, the space in which the heat source unit 2 is installed and the space in which the auxiliary heat source unit 7 is installed must be sufficiently distant from each other or must be separated by a structure, for example.

[0038] In the auxiliary heat exchanger 72, the heat medium that exchanges heat with the refrigerant corresponds to the "second fluid" in the present disclosure. As described above, the "second fluid" is a fluid that has heat or waste heat derived from renewable energy and is thermally independent from the first fluid. In addition to the above-described fluid that has heat or waste heat derived from renewable energy, a fluid that has so-called unused heat may also be used. Unused heat is a general term for thermal energy that has not been utilized in the past.

[0039] The refrigeration cycle apparatus 1 includes a control device 100. The control device 100 controls each device included in the refrigeration cycle apparatus 1 for each operation mode. The operation modes include cooling operation and heating operation. FIG. 2 is a hardware configuration diagram showing the control device 100 according to the first embodiment. As shown in FIG. 2, the control device 100 is dedicated hardware configured with a processing circuit 101 such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). FIG. 3 is a hardware configuration diagram showing the control device 100 according to the first embodiment. When the functions of the control device 100 are performed by software, the control device 100 may be configured with a processor 102 such as a CPU and a memory 103, as shown in FIG. 3. FIG. 3 shows that the processor 102 and the memory 103 are communicably connected to each other via a bus 104. The functions of the control device 100 are realized by the processor 102 reading and executing a program stored in the memory 103. The memory 103 may be a non-volatile or volatile semiconductor memory or a removable recording medium.

[0040] FIG. 4 is a functional block diagram showing a control device 100 according to the first embodiment. As shown in FIG. 4 , the control device 100 is connected to the compressor 21, the flow path switching device 22, the heat source-side blower 24, the load-side expansion device 32, the load-side blower 33, the on-off valves 40 and 41, the first bypass-side expansion device 51, the second bypass-side expansion device 52, the auxiliary-side expansion device 71, and the water pump 91 so that they can communicate with each other wirelessly or via a wire. The control device 100 controls the connection direction of the flow path switching device 22 to switch the operation mode. The control device 100 controls the rotation speed (refrigerant discharge rate) of the compressor 21, the rotation speed of the heat source-side blower 24, the opening degree of the load-side expansion device 32, the rotation speed of the load-side blower 33, the opening degree of the auxiliary-side expansion device 71, and the rotation speed of the water pump 91 so that the room temperature is set to a temperature set by the user.

[0041] The control device 100 opens the first bypass-side throttle device 51 and closes the second bypass-side throttle device 52 during cooling operation. The opening degree of the first bypass-side throttle device 51 in the first embodiment is fixed (for example, 50%). The second bypass-side throttle device 52 may be opened during cooling operation. The control device 100 closes the first bypass-side throttle device 51 and opens the second bypass-side throttle device 52 during heating operation. The opening degree of the second bypass-side throttle device 52 in the first embodiment is fixed (for example, 50%). The first bypass-side throttle device 51 may be opened during heating operation to ensure a differential pressure across the valve downstream of the branching section 602. Regardless of the operating mode, the control device 100 controls the on-off valves 40 and 41 to the open state when blocking the flow of refrigerant to the auxiliary heat source unit 7.

[0042] (Cooling Operation) Here, the operation of the refrigeration cycle apparatus 1 and the flow of refrigerant will be described using FIG. 1 . Only the cooling operation and the heating operation will be described here. First, the cooling operation will be described. The control device 100 performs the cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 is connected to the heat source side heat exchanger 23. In the cooling operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state (single-phase) refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the heat source side heat exchanger 23, which functions as a condenser. The refrigerant flowing into the heat source side heat exchanger 23 exchanges heat with the outdoor air sent by the heat source side blower 24, condenses, and becomes a high-temperature, high-pressure, two-phase gas-liquid state. The high-temperature, high-pressure, two-phase gas-liquid refrigerant flows into the auxiliary heat exchanger 72, which functions as a condenser. The refrigerant that has flowed into the auxiliary heat exchanger 72 exchanges heat with the heat medium and condenses to become a high-pressure liquid. The high-pressure liquid refrigerant is divided at the branching point 602, with a portion flowing toward the load device 3 and the remainder flowing through the first bypass pipe 501.

[0043] The high-pressure liquid refrigerant diverted at the branching section 602 and flowing toward the load device 3 flows into the load-side throttle device 32, where it is decompressed and expanded to become low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the load-side heat exchanger 31, which functions as an evaporator. The refrigerant that flows into the load-side heat exchanger 31 exchanges heat with indoor air sent by the load-side blower 33, causing the liquid phase to evaporate and become gaseous (single-phase). At this time, the indoor air is cooled, thereby cooling the room.

[0044] On the other hand, the high-pressure liquid refrigerant branched at the branching portion 602 flows into the first bypass side throttle device 51, where it is decompressed and expanded to become a low-temperature, low-pressure, gas-liquid two-phase refrigerant.

[0045] The low-temperature, low-pressure gas-state refrigerant flowing out of the load-side heat exchanger 31 merges with the gas-liquid two-phase refrigerant flowing through the first bypass pipe 501 at the branching point 601. As a result, the refrigerant flowing through the relay pipe 401 becomes a gas-based two-phase refrigerant. The gas-based two-phase refrigerant passes through the flow path switching device 22 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated thereafter during the cooling operation of the refrigeration cycle apparatus 1.

[0046] (Heating Operation) Next, heating operation will be described using FIG. 5 . FIG. 5 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle apparatus 1 according to the first embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 is connected to the heat source side heat exchanger 23. During heating operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the load side heat exchanger 31, which functions as a condenser. The refrigerant that flows into the load side heat exchanger 31 exchanges heat with indoor air sent by the load side blower 33, condenses, and becomes a low-temperature liquid state. At this time, the indoor air is heated, and heating is performed in the room. The low-temperature, high-pressure liquid refrigerant is branched at the branching section 603, with a portion flowing toward the auxiliary heat source unit 7 and the remaining portion flowing through the second bypass piping 502.

[0047] The low-temperature, high-pressure liquid refrigerant diverted at the branching section 603 and flowing toward the auxiliary heat exchanger 72 is decompressed by the auxiliary-side throttle device 71 to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The low-temperature, low-pressure, two-phase gas-liquid refrigerant flows into the auxiliary heat exchanger 72, which functions as an evaporator. The low-temperature, low-pressure, two-phase gas-liquid refrigerant that has flowed into the auxiliary heat exchanger 72 exchanges heat with a heat medium, evaporating the liquid phase and becoming a gas (single phase).

[0048] On the other hand, the low-temperature, high-pressure liquid refrigerant branched at the branching portion 603 flows into the second bypass side throttle device 52, where it is decompressed and expanded to become low-temperature, low-pressure, gas-liquid two-phase refrigerant.

[0049] The low-temperature, low-pressure gas-state refrigerant flowing out of the auxiliary heat exchanger 72 merges with the gas-liquid two-phase refrigerant flowing through the second bypass pipe 502 at the branch point 604. As a result, the refrigerant flowing through the relay pipe 403 becomes a gas-based two-phase refrigerant. The low-temperature, low-pressure gas-based two-phase refrigerant flows into the heat-source-side heat exchanger 23, which functions as an evaporator. The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing into the heat-source-side heat exchanger 23 exchanges heat with outdoor air supplied by the heat-source-side blower 24, evaporating the liquid phase and becoming a low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant flowing out of the heat-source-side heat exchanger 23 passes through the flow switching device 22 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated during heating operation of the refrigeration cycle apparatus 1.

[0050] An example of the operation of the control device 100 will be described using FIG. 6 . FIG. 6 is a flowchart showing an example of the operation of the control device 100 according to the first embodiment. First, the control device 100 determines whether the operation mode of the refrigeration cycle apparatus 1 is cooling operation (step S1). If the operation mode is cooling operation (step S1: YES), the control device 100 opens the first bypass-side throttle device 51 (step S2). If the operation mode is not cooling operation, i.e., heating operation (step S2), the control device 100 opens the second bypass-side throttle device 52 (step S3). Note that, although the example described here shows a case in which the refrigeration cycle apparatus 1 can perform two operation modes, cooling operation and heating operation, the refrigeration cycle apparatus 1 may also be capable of performing, for example, a dehumidification operation.

[0051] Generally, one possible way to deal with the excess refrigerant generated by the volume difference between the heat source-side heat exchanger 23 and the auxiliary heat exchanger 72 is to convert the refrigerant into a gas-liquid two-phase state at the outlet of the load-side heat exchanger 31. However, because the gas-liquid ratio of the refrigerant undergoing latent heat change cannot generally be measured, the control target of the load-side throttle device 32 is unclear, resulting in poor controllability. In particular, when the refrigeration cycle system 1 has multiple load devices 3, it becomes impossible to provide the required air conditioning capacity for each load device 3. While reducing the amount of heat medium charged into the refrigeration cycle system 1 is also an option, if the auxiliary heat source unit 7 is stopped and only the heat source unit 2 is used to supply heat or cold to the load devices 3, the refrigerant charge amount and, therefore, the operating capacity will be insufficient, making it impossible to provide the required air conditioning capacity. To overcome this issue, it is possible to increase the capacity of the load devices 3 by enlarging the load-side heat exchanger 31 of the load devices 3, but this would reduce the space within the load devices 3 and reduce space efficiency.

[0052] In contrast, according to the first embodiment, a throttle device provided in the bypass piping is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator or the load-side heat exchanger 31 bypasses the auxiliary heat exchanger 72 or the load-side heat exchanger 31. As a result, an excess amount of refrigerant generated due to the difference in volume between the heat source-side heat exchanger 23 and the auxiliary heat exchanger 72 flows to the heat source unit 2 without passing through the evaporator. This makes it possible to reduce the ratio of gas-phase refrigerant, which has a lower density than liquid-phase refrigerant and gas-liquid two-phase refrigerant, in the piping between the auxiliary heat source unit 7 or the load device 3 and the heat source unit 2. This makes it possible to suppress a decrease in the energy-saving performance of the refrigeration cycle apparatus 1.

[0053] Specifically, during cooling operation, the liquid phase ratio of the refrigerant from the branching portion 601 inside the relay unit 4 to the compressor 21 inside the heat source unit 2 is improved compared to when the first bypass piping 501 is not provided. As a result, the condensation saturation temperature in the heat source unit 2 and the auxiliary heat source unit 7 is lowered, and a decrease in energy-saving performance is suppressed. Furthermore, at this time, there is no need to increase the size of the load-side heat exchanger 31, and therefore a decrease in space efficiency is also suppressed.

[0054] Furthermore, during heating operation, the ratio of gas-liquid two-phase refrigerant from the branching point 604 inside the relay unit 4 to the heat source-side heat exchanger 23 inside the heat source unit 2 is improved compared to when the second bypass piping 502 is not provided. At this time, the volumetric flow rate is reduced, so the pressure loss of the refrigerant from the branching point 604 to the heat source-side heat exchanger 23 is reduced, and a decrease in energy-saving performance is suppressed. In particular, because the pressure loss can be reduced without increasing the piping diameter, a decrease in space efficiency is also suppressed.

[0055] Embodiment 2. Figure 7 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1A according to embodiment 2. As shown in Figure 7, the refrigeration cycle apparatus 1A according to embodiment 3 differs from the refrigeration cycle apparatus 1 according to embodiment 1 in the piping configuration of the relay unit 4A. The following description will focus on the differences with the refrigeration cycle apparatus 1 according to embodiment 1, and will omit a description of the commonalities. Note that in the following drawings, the water pump 91 and the tank 92 may be omitted.

[0056] The heat source unit 2 has a heat source side pipe 202 and a heat source side pipe 203. The heat source unit 2 also has an accumulator 25 and check valves 26 to 29.

[0057] The heat source side piping 202 is a piping provided inside the housing of the heat source unit 2, and has one end connected between the check valve 26 in the heat source side piping 201 and the connection position of the connection piping 801, and the other end connected between the check valve 29 in the heat source side piping 201 and the heat source side heat exchanger 23. The heat source side piping 203 is a piping provided inside the housing of the heat source unit 2, and has one end connected between the check valve 26 in the heat source side piping 201 and the flow path switching device 22, and the other end connected between the check valve 29 in the heat source side piping 201 and the connection position of the connection piping 802.

[0058] The accumulator 25 is provided on the suction side of the compressor 21 and is a container for storing excess refrigerant circulating in the refrigerant circuit.

[0059] The check valve 26 is provided in the heat source side pipe 201 between the connection position of the flow path switching device 22 and the connection pipe 801, and allows the refrigerant to flow from the flow path switching device 22 to the relay unit 4A and blocks the reverse flow. The check valve 27 is provided in the heat source side pipe 203, and allows the refrigerant to flow from the relay unit 4A to the flow path switching device 22 and blocks the reverse flow.

[0060] The check valve 28 is provided in the heat source side piping 202, and allows the refrigerant to flow from the heat source side heat exchanger 23 to the relay unit 4A and blocks the reverse flow. The check valve 29 is provided in the heat source side piping 201 between the heat source side heat exchanger 23 and the connection position of the connection piping 802, and allows the refrigerant to flow from the relay unit 4A to the heat source side heat exchanger 23 and blocks the reverse flow.

[0061] The relay unit 4A has relay pipes 404 to 410 and a third bypass pipe 503. The relay unit 4A also has a third bypass-side throttle device 53 and on-off valves 42 to 47.

[0062] The relay pipe 404 is a pipe provided inside the housing of the relay unit 4A, and one end is connected to the connection pipe 803, and the other end is connected to the relay pipes 405 and 406. The relay pipe 405 is a pipe provided inside the housing of the relay unit 4A, and one end is connected to the relay pipe 404, and the other end is connected to the connection pipe 801. The relay pipe 406 is a pipe provided inside the housing of the relay unit 4A, and one end is connected to the relay pipe 404, and the other end is connected to the connection pipe 802.

[0063] The relay pipe 407 is a pipe provided inside the housing of the relay unit 4A, and has one end connected to the connection pipe 806 and the other end connected to the relay pipes 408 and 409. The relay pipe 408 is a pipe provided inside the housing of the relay unit 4A, and has one end connected to the relay pipe 407 and the other end connected to the relay pipe 405. The relay pipe 409 is a pipe provided inside the housing of the relay unit 4A, and has one end connected to the relay pipe 407 and the other end connected to the relay pipe 406.

[0064] The relay pipe 410 is a pipe provided inside the housing of the relay unit 4A, and one end is connected to the connection pipe 804 and the other end is connected to the connection pipe 805.

[0065] The third bypass pipe 503 is a pipe provided inside the housing of the relay unit 4A, and has one end connected to the relay pipe 406 and the other end connected to the relay pipe 410. The portion where the third bypass pipe 503 connects to the relay pipe 406 is referred to as a branch portion 605. The portion where the third bypass pipe 503 connects to the relay pipe 410 is referred to as a branch portion 606. When the refrigeration cycle apparatus 1A performs cooling operation, a portion of the refrigerant flowing through the relay pipe 410 does not flow through the load-side heat exchanger 31 functioning as an evaporator, but flows through the third bypass pipe 503 via the branch portion 606. In other words, a portion of the refrigerant flowing toward the load-side heat exchanger 31 functioning as an evaporator bypasses the load-side heat exchanger 31. When the refrigeration cycle apparatus 1A performs heating operation, a portion of the refrigerant flowing through the relay pipe 410 does not flow through the auxiliary heat exchanger 72 functioning as an evaporator, but flows through the third bypass pipe 503 via the branch portion 606. That is, a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator bypasses the auxiliary heat exchanger 72 .

[0066] The third bypass-side throttle device 53 is provided in the third bypass pipe 503 and reduces the pressure of the refrigerant flowing through the third bypass pipe 503 to expand it. For example, it is an electric expansion valve that can adjust the flow rate of the refrigerant by changing its opening. Note that the third bypass-side throttle device 53 is not limited to an electric expansion valve, and may be a mechanical expansion valve that uses a diaphragm in the pressure-receiving part. Furthermore, the load-side throttle device 32 may be configured using a capillary tube or the like.

[0067] During cooling operation, the third bypass piping 503 connects the relay piping 410, through which the refrigerant flows from the auxiliary heat exchanger 72 to the load-side heat exchanger 31, to the relay piping 406, through which the refrigerant flows from the load-side heat exchanger 31 to the heat-source-side heat exchanger 23. Similarly, during heating operation, the third bypass piping 503 connects the relay piping 410, through which the refrigerant flows from the load-side heat exchanger 31 to the auxiliary heat exchanger 72, to the relay piping 406, through which the refrigerant flows from the auxiliary heat exchanger 72 to the heat-source-side heat exchanger 23. Therefore, during both cooling operation and heating operation, the third bypass piping 503 and the third bypass-side throttle device 53 correspond to the "bypass piping" and the "bypass-side throttle device" of the present disclosure.

[0068] The on-off valve 42 is a valve provided in the relay pipe 405. The on-off valve 42 switches between an open state in which the refrigerant flows through the relay pipe 405 and a closed state in which the refrigerant flows through the relay pipe 405. The on-off valve 42 is closed during cooling operation and is opened during heating operation. The on-off valve 43 is a valve provided in the relay pipe 406. The on-off valve 43 is switched between an open state in which the refrigerant flows through the relay pipe 406 and a closed state in which the refrigerant flows through the relay pipe 406. The on-off valve 43 is opened during cooling operation and is closed during heating operation.

[0069] The on-off valve 44 is a valve provided in the relay pipe 408. The on-off valve 44 switches between an open state in which the refrigerant flows through the relay pipe 408 and a closed state in which the refrigerant flows through the relay pipe 408. The on-off valve 44 is opened during cooling operation and closed during heating operation. The on-off valve 45 is a valve provided in the relay pipe 409. The on-off valve 45 is switched between an open state in which the refrigerant flows through the relay pipe 409 and a closed state in which the refrigerant flows through the relay pipe 409. The on-off valve 45 is closed during cooling operation and opened during heating operation.

[0070] The on-off valve 46 is a valve provided between the connection position of the connection pipe 804 in the relay pipe 410 and the connection position of the third bypass pipe 503. The on-off valve 46 switches between an open state in which the refrigerant flowing through the relay pipe 410 is permitted to flow, and a closed state in which the refrigerant flowing through the relay pipe 405 is blocked. The on-off valve 47 is a valve provided between the connection position of the connection pipe 805 in the relay pipe 410 and the connection position of the third bypass pipe 503. The on-off valve 47 switches between an open state in which the refrigerant flowing through the relay pipe 405 is permitted to flow, and a closed state in which the refrigerant flowing through the relay pipe 405 is blocked.

[0071] Fig. 8 is a functional block diagram of a refrigeration cycle apparatus 1A according to embodiment 2. As shown in Fig. 8, the control device 100 is connected to the compressor 21, the flow path switching device 22, the heat source side blower 24, the load side expansion device 32, the load side blower 33, the on-off valves 42 to 47, the third bypass side expansion device 53, the auxiliary side expansion device 71, and the water pump 91 so as to be able to communicate wirelessly or by wire. Regarding the control of each device of the refrigeration cycle by the control device 100, only the parts that differ from embodiment 1 will be described.

[0072] During cooling operation and heating operation, the control device 100 opens the third bypass side throttle device 53. Note that the opening degree of the third bypass side throttle device 53 in the second embodiment is fixed (for example, 50%).

[0073] During cooling operation, the control device 100 opens the on-off valves 43, 44, 46, and 47 and closes the on-off valves 42 and 45. During heating operation, the control device 100 opens the on-off valves 42, 45, 46, and 47 and closes the on-off valves 43 and 44.

[0074] (Cooling Operation) Here, the operation of the refrigeration cycle apparatus 1A and the flow of refrigerant will be described using FIG. 7 . First, the cooling operation will be described. The control device 100 performs cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 is connected to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 43, 44, 46, and 47 and closes the on-off valves 42 and 45. During cooling operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state (single-phase) refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the heat source side heat exchanger 23, which functions as a condenser. The refrigerant flowing into the heat source side heat exchanger 23 exchanges heat with outdoor air sent by the heat source side blower 24, condenses, and becomes a high-temperature, high-pressure two-phase gas-liquid state. The high-temperature, high-pressure refrigerant in a gas-liquid two-phase state passes through relay pipes 405, 408, and 407 of the relay unit 4A and flows into the auxiliary heat exchanger 72, which functions as a condenser. The refrigerant that flows into the auxiliary heat exchanger 72 exchanges heat with the heat medium and condenses, becoming a high-pressure liquid. The high-pressure liquid refrigerant passes through relay pipe 410 of the relay unit 4A and is branched at branch point 606, with a portion flowing toward the load device 3 and the remainder flowing through the third bypass pipe 503.

[0075] The high-pressure liquid refrigerant diverted at the branching section 606 and flowing toward the load device 3 flows into the load-side throttle device 32, where it is decompressed and expanded to become low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the load-side heat exchanger 31, which functions as an evaporator. The refrigerant that flows into the load-side heat exchanger 31 exchanges heat with indoor air sent by the load-side blower 33, causing the liquid phase to evaporate and become gaseous (single-phase). At this time, the indoor air is cooled, thereby cooling the room.

[0076] On the other hand, the high-pressure liquid refrigerant branched at the branching portion 606 flows into the third bypass side throttle device 53, where it is decompressed and expanded to become low-temperature, low-pressure gas-liquid two-phase refrigerant.

[0077] The low-temperature, low-pressure gas-state refrigerant flowing out of the load-side heat exchanger 31 passes through the relay pipes 404 and 406 of the relay unit 4A and merges with the gas-liquid two-phase refrigerant flowing through the third bypass pipe 503 at the branch point 605. As a result, the refrigerant flowing through the relay pipe 406 becomes a gas-based two-phase refrigerant. The gas-based two-phase refrigerant passes through the flow switching device 22 and the accumulator 25 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated thereafter during the cooling operation of the refrigeration cycle apparatus 1A.

[0078] (Heating Operation) Next, the heating operation will be described using FIG. 9 . FIG. 9 is a refrigerant circuit diagram showing the refrigerant flow during heating operation of the refrigeration cycle apparatus 1A according to the second embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 is connected to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 42, 45, 46, and 47 and closes the on-off valves 43 and 44. During heating operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 21 passes through the flow path switching device 22, passes through the relay pipes 405 and 404 of the relay unit 4A, and flows into the load side heat exchanger 31, which functions as a condenser. The refrigerant flowing into the load side heat exchanger 31 exchanges heat with indoor air sent by the load side blower 33, condenses, and becomes a low-temperature liquid. At this time, the indoor air is heated, and heating is performed in the room. The low-temperature, high-pressure liquid refrigerant passes through the relay pipe 410 of the relay unit 4A and is divided at the branching point 606, with a portion flowing toward the auxiliary heat source unit 7 and the remainder flowing through the third bypass pipe 503.

[0079] The low-temperature, high-pressure liquid refrigerant diverted at the branching portion 606 and flowing toward the auxiliary heat exchanger 72 flows into the auxiliary-side throttle device 71, where it is decompressed and becomes a low-temperature, low-pressure, two-phase refrigerant in a gas-liquid state. The low-temperature, low-pressure, two-phase refrigerant flows into the auxiliary heat exchanger 72, which functions as an evaporator. The low-temperature, low-pressure, two-phase refrigerant that has flowed into the auxiliary heat exchanger 72 exchanges heat with a heat medium, evaporating the liquid phase and becoming a gas (single phase).

[0080] On the other hand, the low-temperature, high-pressure liquid refrigerant branched at the branching portion 606 flows into the third bypass side throttle device 53, where it is decompressed and expanded to become low-temperature, low-pressure, gas-liquid two-phase refrigerant.

[0081] The low-temperature, low-pressure gas-state refrigerant flowing out of the auxiliary heat exchanger 72 passes through the relay pipes 407, 409, and 406 of the relay unit 4A and merges with the two-phase gas-liquid refrigerant flowing through the third bypass pipe 503 at the branch point 605. As a result, the refrigerant flowing through the relay pipe 406 becomes a gas-predominant two-phase gas-liquid refrigerant. The low-temperature, low-pressure gas-predominant two-phase gas-liquid refrigerant flows into the heat-source-side heat exchanger 23, which functions as an evaporator. The low-temperature, low-pressure two-phase gas-liquid refrigerant flowing into the heat-source-side heat exchanger 23 exchanges heat with outdoor air supplied by the heat-source-side blower 24, evaporating the liquid phase and becoming low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant flowing out of the heat-source-side heat exchanger 23 passes through the flow switching device 22 and the accumulator 25 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. During the heating operation of the refrigeration cycle apparatus 1A, this cycle is repeated.

[0082] As described above, according to the second embodiment, similarly to the first embodiment, the throttle device provided in the bypass piping is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator or the load-side heat exchanger 31 bypasses the auxiliary heat exchanger 72 or the load-side heat exchanger 31. Therefore, the refrigeration cycle apparatus 1A can suppress a decrease in energy-saving performance.

[0083] Embodiment 3. Fig. 10 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1B according to embodiment 3. As shown in Fig. 10, the refrigeration cycle apparatus 1B of embodiment 3 differs from the refrigeration cycle apparatus 1A of embodiment 2 in the piping configuration of the relay unit 4B. The following description will focus on the differences from the refrigeration cycle apparatus 1B of embodiment 2, and will omit a description of the commonalities.

[0084] The relay unit 4B has relay pipes 404 to 409 and 411 to 417, and a fourth bypass pipe 504. The relay unit 4B also has a fourth bypass-side throttle device 54 and on-off valves 42 to 45. The relay unit 4B also has check valves 61 to 64. The relay pipes 404 to 409 and on-off valves 42 to 45 have the same configuration as in the second embodiment.

[0085] The relay pipe 411 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the connection pipe 804 and the other end connected to the relay pipes 412 and 413. The connection portion between the relay pipe 411 and the relay pipes 412 and 413 is referred to as a branch portion 607. The relay pipe 412 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the relay pipe 411 and the other end connected to the relay pipes 415 and 417 and the fourth bypass pipe 504. The connection portion between the relay pipe 411 and the relay pipes 415 and 417 and the fourth bypass pipe 504 is referred to as a branch portion 608. The relay pipe 413 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the relay pipe 411 and the other end connected to the relay pipes 416 and 417. The connection portion between the relay pipe 411 and the relay pipes 416 and 417 is called a branch portion 609 .

[0086] The relay pipe 414 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the connection pipe 805 and the other end connected to the relay pipes 415 and 416. The connection portion between the relay pipe 414 and the relay pipes 415 and 416 is referred to as a branch section 610. The relay pipe 415 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the relay pipe 414 at the branch section 610 and the other end connected to the relay pipes 412 and 417 and the fourth bypass pipe 504 at the branch section 608. The relay pipe 416 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the relay pipe 414 at the branch section 610 and the other end connected to the relay pipes 413 and 417 at the branch section 609.

[0087] The relay pipe 417 is a pipe provided inside the housing of the relay unit 4B, and one end is connected to the relay pipes 412 and 415 and the fourth bypass pipe 504 at the branching point 608, and the other end is connected to the relay pipes 413 and 416 at the branching point 609.

[0088] The fourth bypass pipe 504 is a pipe provided inside the housing of the relay unit 4B, and has one end connected to the relay pipe 406 and the other end connected to the relay pipe 411 at a branch portion 608. The portion where the fourth bypass pipe 504 connects to the relay pipe 406 is referred to as a branch portion 611. When the refrigeration cycle apparatus 1B performs cooling operation, a portion of the refrigerant flowing through the relay pipe 415 does not flow through the load-side heat exchanger 31 functioning as an evaporator, but flows through the fourth bypass pipe 504 via the branch portion 608. In other words, a portion of the refrigerant flowing toward the load-side heat exchanger 31 functioning as an evaporator bypasses the load-side heat exchanger 31. When the refrigeration cycle apparatus 1B performs heating operation, a portion of the refrigerant flowing through the relay pipe 412 does not flow through the auxiliary heat exchanger 72 functioning as an evaporator, but flows through the fourth bypass pipe 504 via the branch portion 608. In other words, a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 functioning as an evaporator bypasses the auxiliary heat exchanger 72.

[0089] The fourth bypass side throttle device 54 is provided in the fourth bypass pipe 504 and reduces the pressure of the refrigerant flowing through the fourth bypass pipe 504 to expand it. For example, it is an electric expansion valve that can adjust the flow rate of the refrigerant by changing its opening. Note that the fourth bypass side throttle device 54 is not limited to an electric expansion valve, and may be a mechanical expansion valve that uses a diaphragm in the pressure-receiving part. Also, the load side throttle device 32 may be configured with a capillary tube or the like.

[0090] During cooling operation, the fourth bypass piping 504 connects the relay piping 415 and 417 through which the refrigerant flows from the auxiliary heat exchanger 72 to the load-side heat exchanger 31, and the relay piping 406 through which the refrigerant flows from the load-side heat exchanger 31 to the heat-source-side heat exchanger 23. Similarly, during heating operation, the fourth bypass piping 504 connects the relay piping 412 and 417 through which the refrigerant flows from the load-side heat exchanger 31 to the auxiliary heat exchanger 72, and the relay piping 406 through which the refrigerant flows from the auxiliary heat exchanger 72 to the heat-source-side heat exchanger 23. Therefore, during both cooling operation and heating operation, the fourth bypass piping 504 and the fourth bypass-side throttle device 54 correspond to the "bypass piping" and the "bypass-side throttle device" of the present disclosure.

[0091] Check valve 61 is provided in relay pipe 412, and allows refrigerant to flow from branch portion 607 to branch portion 608, while blocking the reverse flow. Check valve 62 is provided in relay pipe 413, and allows refrigerant to flow from branch portion 609 to branch portion 607, while blocking the reverse flow.

[0092] Check valve 63 is provided in relay pipe 415, and allows refrigerant to flow from branch portion 610 to branch portion 608, while blocking the reverse flow. Check valve 64 is provided in relay pipe 416, and allows refrigerant to flow from branch portion 609 to branch portion 610, while blocking the reverse flow.

[0093] Fig. 11 is a functional block diagram of a refrigeration cycle apparatus 1B according to embodiment 3. As shown in Fig. 11, the control device 100 is connected to the compressor 21, the flow path switching device 22, the heat source side blower 24, the load side expansion device 32, the load side blower 33, the on-off valves 42 to 44, the fourth bypass side expansion device 54, the auxiliary side expansion device 71, and the water pump 91 so as to be able to communicate wirelessly or by wire. Regarding the control of each device of the refrigeration cycle by the control device 100, only the parts that differ from embodiment 2 will be described.

[0094] During cooling operation and heating operation, the control device 100 opens the fourth bypass side throttle device 54. Note that the opening degree of the fourth bypass side throttle device 54 in the third embodiment is fixed (for example, 50%).

[0095] (Cooling Operation) Here, the operation of the refrigeration cycle apparatus 1B and the flow of refrigerant will be described using FIG. 10 . First, the cooling operation will be described. The control device 100 performs cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 is connected to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 43 and 44 and closes the on-off valves 42 and 45. During cooling operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state (single-phase) refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the heat source side heat exchanger 23, which functions as a condenser. The refrigerant flowing into the heat source side heat exchanger 23 exchanges heat with outdoor air sent by the heat source side blower 24, condenses, and becomes a high-temperature, high-pressure two-phase gas-liquid state. The high-temperature, high-pressure refrigerant in a gas-liquid two-phase state passes through relay pipes 405, 408, and 407 of the relay unit 4B and flows into the auxiliary heat exchanger 72, which functions as a condenser. The refrigerant that flows into the auxiliary heat exchanger 72 exchanges heat with the heat medium and condenses, becoming a high-pressure liquid. The high-pressure liquid refrigerant passes through relay pipes 414 and 415 of the relay unit 4B and is branched at branch point 608, with a portion flowing toward the load device 3 and the remainder flowing through the third bypass pipe 503.

[0096] The high-pressure liquid refrigerant diverted at the branch point 608 and flowing toward the load device 3 passes through the relay pipes 417, 413, and 411 of the relay unit 4B and flows into the load-side throttle device 32, where it is decompressed and expanded to become low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the load-side heat exchanger 31, which functions as an evaporator. The refrigerant that flows into the load-side heat exchanger 31 exchanges heat with indoor air sent by the load-side blower 33, causing the liquid phase to evaporate and become gaseous (single-phase). At this time, the indoor air is cooled, thereby cooling the room.

[0097] On the other hand, the high-pressure liquid refrigerant branched at the branching portion 608 flows into the fourth bypass side throttle device 54, where it is decompressed and expanded to become low-temperature, low-pressure gas-liquid two-phase refrigerant.

[0098] The low-temperature, low-pressure gas-state refrigerant flowing out of the load-side heat exchanger 31 passes through the relay pipes 404 and 406 of the relay unit 4B and merges with the gas-liquid two-phase refrigerant flowing through the third bypass pipe 503 at the branch point 611. As a result, the refrigerant flowing through the relay pipe 406 becomes a gas-based two-phase refrigerant. The gas-based two-phase refrigerant passes through the flow switching device 22 and the accumulator 25 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated thereafter during the cooling operation of the refrigeration cycle apparatus 1B.

[0099] (Heating Operation) Next, heating operation will be described using FIG. 12 . FIG. 12 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle apparatus 1B according to the third embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 is connected to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 42 and 45 and closes the on-off valves 43 and 44. During heating operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and the relay pipes 405 and 404 of the relay unit 4B before flowing into the load side heat exchanger 31, which functions as a condenser. The refrigerant that flows into the load side heat exchanger 31 exchanges heat with indoor air sent by the load side blower 33, condenses, and becomes a low-temperature liquid. At this time, the indoor air is heated, and heating is performed in the room. The low-temperature, high-pressure liquid refrigerant passes through the relay pipes 411 and 412 of the relay unit 4B and is divided at the branching point 608, with a portion flowing toward the auxiliary heat source unit 7 and the remainder flowing through the fourth bypass pipe 504.

[0100] The low-temperature, high-pressure liquid refrigerant branched at branch section 608 and flowing toward the auxiliary heat exchanger 72 passes through relay pipes 417, 416, and 414 of relay unit 4B, flows into the auxiliary-side throttle device 71, and is decompressed to become low-temperature, low-pressure, two-phase refrigerant in a gas-liquid state. The low-temperature, low-pressure, two-phase refrigerant in a gas-liquid state flows into the auxiliary heat exchanger 72, which functions as an evaporator. The low-temperature, low-pressure, two-phase refrigerant that has flowed into the auxiliary heat exchanger 72 exchanges heat with a heat medium, evaporating the liquid phase and becoming a gas (single phase).

[0101] On the other hand, the low-temperature, high-pressure liquid refrigerant branched at the branching portion 608 flows into the fourth bypass side throttle device 54, where it is decompressed and expanded to become low-temperature, low-pressure, gas-liquid two-phase refrigerant.

[0102] The low-temperature, low-pressure gas-state refrigerant flowing out of the auxiliary heat exchanger 72 passes through the relay pipes 407, 409, and 406 of the relay unit 4B and merges with the two-phase gas-liquid refrigerant flowing through the fourth bypass pipe 504 at the branch point 611. As a result, the refrigerant flowing through the relay pipe 406 becomes a gas-predominant two-phase gas-liquid refrigerant. The low-temperature, low-pressure gas-predominant two-phase gas-liquid refrigerant flows into the heat-source-side heat exchanger 23, which functions as an evaporator. The low-temperature, low-pressure two-phase gas-liquid refrigerant flowing into the heat-source-side heat exchanger 23 exchanges heat with outdoor air supplied by the heat-source-side blower 24, evaporating the liquid phase and becoming low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant flowing out of the heat-source-side heat exchanger 23 passes through the flow switching device 22 and the accumulator 25 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. During the heating operation of the refrigeration cycle apparatus 1B, this cycle is repeated.

[0103] As described above, according to the third embodiment, similarly to the second embodiment, the throttle device provided in the bypass piping is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator or the load-side heat exchanger 31 bypasses the auxiliary heat exchanger 72 or the load-side heat exchanger 31. Therefore, the refrigeration cycle apparatus 1B can suppress a decrease in energy-saving performance.

[0104] Embodiment 4. Fig. 13 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1C according to embodiment 4. As shown in Fig. 13, the refrigeration cycle apparatus 1C of embodiment 4 differs from the refrigeration cycle apparatus 1B of embodiment 3 in that a relay unit 4C includes a refrigerant heat exchanger 65. The following description will focus on the differences from the refrigeration cycle apparatus 1B of embodiment 3, and will omit a description of the commonalities.

[0105] The relay unit 4C has relay pipes 404 to 409 and 411 to 417, and a fifth bypass pipe 505. The relay unit 4C also has a fifth bypass-side throttle device 55 and on-off valves 42 to 45. The relay unit 4C has check valves 61 to 64. The relay unit 4C also has an inter-refrigerant heat exchanger 65 that exchanges heat between the refrigerant flowing through the relay pipe 417 and the refrigerant flowing through the fifth bypass pipe 505. The relay pipes 404 to 409 and 411 to 417, the on-off valves 42 to 45, and the check valves 61 to 64 have the same configuration as in the third embodiment.

[0106] The refrigerant-to-refrigerant heat exchanger 65 exchanges heat between the refrigerant flowing upstream of the fifth bypass side throttle device 55 and the refrigerant flowing downstream of the fifth bypass side throttle device 55. The refrigerant-to-refrigerant heat exchanger 65 has a first refrigerant flow path 651 to which the relay pipe 417 is connected and through which the refrigerant upstream of the fifth bypass side throttle device 55 flows, and a second refrigerant flow path 652 to which the fifth bypass pipe 505 is connected and through which the refrigerant downstream of the fifth bypass side throttle device 55 flows. The refrigerant flowing through the first refrigerant flow path 651, which is upstream of the fifth bypass side throttle device 55, has a higher pressure than the refrigerant flowing through the second refrigerant flow path 652, which is downstream of the fifth bypass side throttle device 55.

[0107] The fifth bypass pipe 505 is a pipe provided inside the housing of the relay unit 4C, and has one end connected to the relay pipe 406 and the other end connected to the relay pipe 417. The portion where the fifth bypass pipe 505 connects to the relay pipe 406 is referred to as a branch portion 612. The portion where the fifth bypass pipe 505 connects to the relay pipe 417 is referred to as a branch portion 613. When the refrigeration cycle apparatus 1C performs cooling operation, a portion of the refrigerant flowing through the relay pipe 417 does not flow through the load-side heat exchanger 31 functioning as an evaporator, but flows to the fifth bypass pipe 505 via the branch portion 613. In other words, a portion of the refrigerant flowing toward the load-side heat exchanger 31 functioning as an evaporator bypasses the load-side heat exchanger 31. When the refrigeration cycle apparatus 1C performs heating operation, a portion of the refrigerant flowing through the relay pipe 417 does not flow through the auxiliary heat exchanger 72 functioning as an evaporator, but flows to the fifth bypass pipe 505 via the branch portion 613. That is, a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator bypasses the auxiliary heat exchanger 72 .

[0108] The fifth bypass-side throttle device 55 is provided in the fifth bypass pipe 505 and reduces the pressure of the refrigerant flowing through the fifth bypass pipe 505 to expand it. For example, it is an electric expansion valve that can adjust the flow rate of the refrigerant by changing its opening. Note that the fifth bypass-side throttle device 55 is not limited to an electric expansion valve, and may be a mechanical expansion valve that uses a diaphragm in the pressure-receiving part. Also, the load-side throttle device 32 may be configured with a capillary tube or the like.

[0109] During cooling operation, the fifth bypass piping 505 connects the relay piping 417 through which the refrigerant flows from the auxiliary heat exchanger 72 to the load-side heat exchanger 31, and the relay piping 406 through which the refrigerant flows from the load-side heat exchanger 31 to the heat-source-side heat exchanger 23. Similarly, during heating operation, the fifth bypass piping 505 connects the relay piping 417 through which the refrigerant flows from the load-side heat exchanger 31 to the auxiliary heat exchanger 72, and the relay piping 406 through which the refrigerant flows from the auxiliary heat exchanger 72 to the heat-source-side heat exchanger 23. Therefore, during both cooling operation and heating operation, the fifth bypass piping 505 and the fifth bypass-side throttle device 55 correspond to the "bypass piping" and the "bypass-side throttle device" of the present disclosure.

[0110] Fig. 14 is a functional block diagram of a refrigeration cycle apparatus 1C according to embodiment 3. As shown in Fig. 14, the control device 100 is connected to the compressor 21, the flow path switching device 22, the heat source side blower 24, the load side expansion device 32, the load side blower 33, the on-off valves 42 to 45, the fifth bypass side expansion device 55, the auxiliary side expansion device 71, and the water pump 91 so as to be able to communicate wirelessly or by wire. Regarding the control of each device of the refrigeration cycle by the control device 100, only the parts that differ from embodiment 3 will be described.

[0111] During cooling operation and heating operation, the control device 100 opens the fifth bypass side throttle device 55. In the fourth embodiment, the opening degree of the fifth bypass side throttle device 55 is fixed (for example, 50%).

[0112] (Cooling Operation) Here, the operation of the refrigeration cycle apparatus 1C and the flow of refrigerant will be described using FIG. 13 . First, the cooling operation will be described. The control device 100 performs cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 is connected to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 43 and 44 and closes the on-off valves 42 and 45. During cooling operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state (single-phase) refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the heat source side heat exchanger 23, which functions as a condenser. The refrigerant flowing into the heat source side heat exchanger 23 exchanges heat with outdoor air sent by the heat source side blower 24, condenses, and becomes a high-temperature, high-pressure two-phase gas-liquid state. The high-temperature, high-pressure refrigerant in a gas-liquid two-phase state flows through relay pipes 405, 408, and 407 of the relay unit 4C and into the auxiliary heat exchanger 72, which functions as a condenser. The refrigerant that flows into the auxiliary heat exchanger 72 exchanges heat with the heat medium and condenses, becoming a high-pressure liquid. The high-pressure liquid refrigerant flows through relay pipes 414, 415, and 417 of the relay unit 4C and into the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65. The high-pressure refrigerant flowing through the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65 exchanges heat with the low-pressure refrigerant flowing through the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65 and is cooled. The refrigerant that flows out of the inter-refrigerant heat exchanger 65 is branched at a branch point 613; a portion flows toward the load device 3 and the remainder flows through the fifth bypass pipe 505.

[0113] The high-pressure liquid refrigerant diverted at the branch point 613 and flowing toward the load device 3 passes through the relay pipes 417, 413, and 411 of the relay unit 4C and flows into the load-side throttle device 32, where it is decompressed and expanded to become low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the load-side heat exchanger 31, which functions as an evaporator. The refrigerant that flows into the load-side heat exchanger 31 exchanges heat with indoor air sent by the load-side blower 33, causing the liquid phase to evaporate and become gaseous (single-phase). At this time, the indoor air is cooled, thereby cooling the room.

[0114] On the other hand, the high-pressure liquid refrigerant branched at the branching portion 613 flows into the fifth bypass side throttle device 55, where it is decompressed and expanded to become low-temperature, low-pressure, two-phase gas-liquid refrigerant. The low-temperature, low-pressure, two-phase gas-liquid refrigerant flows into the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65. The high-pressure refrigerant flowing through the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65 exchanges heat with the high-pressure refrigerant flowing through the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65, and is heated.

[0115] The low-temperature, low-pressure gas-state refrigerant flowing out of the load-side heat exchanger 31 passes through the relay pipes 404 and 406 of the relay unit 4C and merges with the two-phase gas-liquid refrigerant flowing through the fifth bypass pipe 505 at the branch point 612. As a result, the refrigerant flowing through the relay pipe 406 becomes a gas-dominated two-phase gas-liquid refrigerant. The gas-dominated two-phase gas-liquid refrigerant passes through the flow switching device 22 and the accumulator 25, flows back into the compressor 21, is compressed, and is discharged in a high-temperature, high-pressure gas state. This cycle is repeated thereafter during cooling operation of the refrigeration cycle apparatus 1C.

[0116] In the above description, an example was given in which the refrigerant flowing out of the auxiliary heat source unit 7 is in a liquid state, but depending on the number of operating auxiliary heat source units 7 and load devices 3 and their operating conditions, the refrigerant flowing out of the auxiliary heat source unit 7 may be in a gas-liquid two-phase state. In this case, the gas-liquid two-phase refrigerant flows through the relay pipes 414, 415, and 417 of the relay unit 4C and into the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65, where it exchanges heat with the refrigerant flowing in the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65 and becomes liquid. Therefore, by providing the inter-refrigerant heat exchanger 65, the refrigerant flowing through the branching portion 613 is in a liquid state regardless of the phase state when it flowed out of the auxiliary heat source unit 7.

[0117] (Heating Operation) Next, heating operation will be described using FIG. 15 . FIG. 15 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle apparatus 1C according to the first embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 is connected to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 42 and 45 and closes the on-off valves 43 and 44. During heating operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 21 passes through the flow path switching device 22, passes through the relay pipes 405 and 404 of the relay unit 4C, and flows into the load side heat exchanger 31, which functions as a condenser. The refrigerant that flows into the load side heat exchanger 31 exchanges heat with indoor air sent by the load side blower 33, condenses, and becomes a low-temperature liquid. At that time, the indoor air is heated, and heating is performed in the room. The low-temperature, high-pressure refrigerant in a liquid state passes through the relay pipes 411, 412, and 417 of the relay unit 4C and flows into the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65. The high-pressure refrigerant flowing through the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65 exchanges heat with the low-pressure refrigerant flowing through the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65, and is cooled. The refrigerant that flows out of the inter-refrigerant heat exchanger 65 is branched at the branching portion 613, with a portion flowing toward the auxiliary heat source unit 7 and the remainder flowing through the fourth bypass pipe 504.

[0118] The low-temperature, high-pressure liquid refrigerant branched at the branching section 613 and flowing toward the auxiliary heat exchanger 72 passes through the relay pipes 417, 416, and 414 of the relay unit 4C, flows into the auxiliary-side throttle device 71, and is decompressed to become low-temperature, low-pressure, two-phase refrigerant in a gas-liquid state. The low-temperature, low-pressure, two-phase refrigerant flows into the auxiliary heat exchanger 72, which functions as an evaporator. The low-temperature, low-pressure, two-phase refrigerant that has flowed into the auxiliary heat exchanger 72 exchanges heat with the heat medium, evaporating the liquid phase and becoming a gas (single phase).

[0119] On the other hand, the low-temperature, high-pressure liquid refrigerant branched at the branching portion 613 flows into the fifth bypass side throttle device 55, where it is decompressed and expanded to become low-temperature, low-pressure, two-phase refrigerant in a gas-liquid state. The low-temperature, low-pressure, two-phase refrigerant in a gas-liquid state flows into the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65. The low-pressure refrigerant flowing through the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65 exchanges heat with the high-pressure refrigerant flowing through the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65, and is heated.

[0120] The low-temperature, low-pressure gas-state refrigerant flowing out of the auxiliary heat exchanger 72 passes through the relay pipes 407, 409, and 406 of the relay unit 4C and merges with the two-phase gas-liquid refrigerant flowing through the fifth bypass pipe 505 at the branch point 611. As a result, the refrigerant flowing through the relay pipe 406 becomes a gas-predominant two-phase gas-liquid refrigerant. The low-temperature, low-pressure gas-predominant two-phase gas-liquid refrigerant flows into the heat-source-side heat exchanger 23, which functions as an evaporator. The low-temperature, low-pressure two-phase gas-liquid refrigerant flowing into the heat-source-side heat exchanger 23 exchanges heat with outdoor air supplied by the heat-source-side blower 24, evaporating the liquid phase and becoming low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant flowing out of the heat-source-side heat exchanger 23 passes through the flow switching device 22 and the accumulator 25 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. During the heating operation of the refrigeration cycle apparatus 1C, this cycle is repeated.

[0121] As in the case of cooling operation, the above description has been given with reference to an example in which the refrigerant flowing out of the load device 3 is in a liquid state, but depending on the number of operating auxiliary heat source units 7 and load devices 3 and the operating conditions, the refrigerant flowing out of the load device 3 may be in a gas-liquid two-phase state. In this case, the gas-liquid two-phase refrigerant flows through the relay pipes 411, 412, and 417 of the relay unit 4C and into the first refrigerant flow path 651 of the inter-refrigerant heat exchanger 65, where it exchanges heat with the refrigerant flowing in the second refrigerant flow path 652 of the inter-refrigerant heat exchanger 65 and becomes liquid. Therefore, by providing the inter-refrigerant heat exchanger 65, the refrigerant flowing through the branching section 613 is in a liquid state regardless of the phase state when it flowed out of the auxiliary heat source unit 7.

[0122] As described above, according to the fourth embodiment, similarly to the third embodiment, the throttle device provided in the bypass piping is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator or the load-side heat exchanger 31 bypasses the auxiliary heat exchanger 72 or the load-side heat exchanger 31. Therefore, the refrigeration cycle apparatus 1C can suppress a decrease in energy-saving performance.

[0123] Furthermore, if the refrigerant flowing through the branch 613 is in a gas-liquid two-phase state, it may be difficult to adjust the distribution of the refrigerant flow rate between the load device 3 or auxiliary heat source unit 7 acting as an evaporator and the fifth bypass pipe 505, resulting in inappropriate distribution of the refrigerant. For example, refrigerant in either a gas or liquid state may be concentrated toward the evaporator side or the fifth bypass pipe 505 side. In this case, the energy-saving performance of the refrigeration cycle apparatus 1C may be reduced. In contrast, according to the fourth embodiment, the refrigerant flowing through the branch 613 is in a liquid state by providing the refrigerant-to-refrigerant heat exchanger 65. This makes it possible to adjust the distribution of the refrigerant flow rate between the evaporator side and the fifth bypass pipe 505 side. Therefore, the refrigerant flowing through the relay pipe 406 is in a gas-liquid two-phase state, with the refrigerant flowing through the relay pipe 406 being mainly gas. This improves the liquid-phase ratio of the refrigerant from the branch 612 to the compressor 21 during cooling operation. Furthermore, the pressure loss of the refrigerant from the branch 612 to the heat-source-side heat exchanger 23 during heating operation is reduced. Therefore, the refrigeration cycle apparatus 1C can suppress a decrease in energy-saving performance.

[0124] Embodiment 5. Fig. 16 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1D according to embodiment 6. As shown in Fig. 16, the refrigeration cycle apparatus 1D of embodiment 6 differs from the refrigeration cycle apparatus 1 of embodiment 1 in that it has a gas-liquid separator 66. The following description will focus on the differences from the refrigeration cycle apparatus 1D of embodiment 1, and will omit a description of the commonalities.

[0125] The relay unit 4D has a gas-liquid separator 66. The gas-liquid separator 66 is provided in the relay pipe 403 between the portion where the connection pipe 802 is connected and the on-off valve 41. The second bypass pipe 502 is also connected to the gas-liquid separator 66. During cooling operation, the gas-liquid separator 66 separates the refrigerant that has flowed into the gas-liquid separator 66 into a gas phase and a liquid phase, and causes the gaseous refrigerant to flow into the relay pipe 403 and the liquid refrigerant to flow into the second bypass pipe 502.

[0126] As described above, according to the sixth embodiment, the refrigeration cycle apparatus 1D includes the gas-liquid separator 66. Therefore, during cooling operation, gaseous refrigerant can be selectively distributed to the auxiliary heat exchanger 72. This improves the condensation performance of the auxiliary heat exchanger 72. Furthermore, since the amount of liquid refrigerant circulating through the first bypass pipe 501 can be increased, the liquid phase ratio of the refrigerant from the branching portion 601 to the compressor 21 is improved. Therefore, the refrigeration cycle apparatus 1D can suppress a decrease in energy-saving performance.

[0127] Sixth Embodiment Fig. 17 is a refrigerant circuit diagram showing a refrigeration cycle apparatus 1E according to a sixth embodiment. As shown in Fig. 17, the refrigeration cycle apparatus 1E of the sixth embodiment differs from the refrigeration cycle apparatus 1 of the first embodiment in that a heat medium temperature measuring device 93 is provided in a heat medium pipe 901. The following description will focus on the differences from the refrigeration cycle apparatus 1E of the first embodiment, and will omit a description of the commonalities.

[0128] The heat medium temperature measuring device 93 is provided in the heat medium pipe 901. The heat medium temperature measuring device 93 measures the temperature of the heat medium flowing through the water circuit. The heat medium temperature measuring device 93 transmits the measurement result to the control device 100.

[0129] Fig. 18 is a functional block diagram of a refrigeration cycle apparatus 1E according to Embodiment 6. As shown in Fig. 18 , the control device 100 controls the apertures of the first bypass side throttle device 51 and the second bypass side throttle device 52 based on the measurement results of the heat medium temperature measuring device 93. Specifically, the control device 100 comprehensively determines the apertures of the first bypass side throttle device 51 and the second bypass side throttle device 52 so that the heat recovery ratio and the heat release ratio of the heat source unit 2 and the auxiliary heat source unit 7 fall within predetermined ranges.

[0130] If the water circuit 8 were not used, it would be possible to estimate the amount of heat recovered by the auxiliary heat source unit 7 from the heat source by measuring the temperature and pressure of the refrigerant undergoing latent heat change. However, for refrigerant in a gas-liquid two-phase state, there are many regions where the correlation between the temperature and pressure information and the latent heat it possesses is low, making it difficult to estimate the amount of heat recovered. This reduces the controllability of the heat recovery ratio and heat release ratio between the heat source unit 2 and the auxiliary heat source unit 7. As a result, the flow rate ratio between the refrigerant flowing through the bypass piping and the refrigerant flowing through the auxiliary heat exchanger 72 and the load-side heat exchanger 31, which function as an evaporator, deviates from the appropriate range, thereby reducing energy-saving performance.

[0131] In contrast, the refrigeration cycle apparatus 1E performs heat exchange between the refrigerant flowing through the refrigerant circuit and the heat medium flowing through the water circuit 8. A heat medium temperature measuring device 93 is provided in the heat medium piping 901 to measure the temperature of the heat medium. The openings of the first bypass side throttle device 51 and the second bypass side throttle device 52 are adjusted based on the measurement results of the heat medium temperature, thereby controlling the heat recovery ratio and heat release ratio between the heat source unit 2 and the auxiliary heat source unit 7. This improves energy-saving performance. Furthermore, by using a heat medium with a small change in latent heat, the heat recovery ratio and heat release ratio between the heat source unit 2 and the auxiliary heat source unit 7 can be more accurately controlled based on the measurement results of the heat medium temperature.

[0132] Seventh Embodiment Fig. 19 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1F according to a seventh embodiment. As shown in Fig. 19, the refrigeration cycle apparatus 1F of the sixth embodiment differs from the refrigeration cycle apparatus 1 of the first embodiment in that it has a plurality of load devices 3a and 3b. The following description will focus on the differences from the refrigeration cycle apparatus 1 of the first embodiment, and will omit a description of the commonalities.

[0133] The refrigeration cycle apparatus 1F includes load devices 3a and 3b. The load device 3a and the relay unit 4E are connected by connection pipes 803a and 804a. The load device 3b and the relay unit 4E are connected by connection pipes 803b and 804b.

[0134] The load device 3a includes a load-side pipe 301a. The load device 3 also includes a load-side heat exchanger 31a, a load-side throttle device 32a, and a load-side blower 33a.

[0135] The load-side pipe 301a is a pipe provided inside the housing (not shown) of the load device 3a, and one end is connected to the connection pipe 803a and the other end is connected to the connection pipe 804a. The load-side pipe 301a connects the load-side heat exchanger 31a and the load-side expansion device 32a. Refrigerant flows inside the load-side pipe 301a.

[0136] The load-side heat exchanger 31a, the load-side throttle device 32a, and the load-side blower 33a of the load device 3a of embodiment 7 have the same configuration as the load-side heat exchanger 31, the load-side throttle device 32, and the load-side blower 33 of the load device 3 of embodiment 1. Therefore, detailed description of the load-side heat exchanger 31a, the load-side throttle device 32a, and the load-side blower 33a of the load device 3a of embodiment 7 will be omitted.

[0137] The load device 3b has a load-side pipe 301b. The load device 3b also has a load-side heat exchanger 31b, a load-side throttle device 32b, and a load-side fan 33b.

[0138] The load-side pipe 301b is a pipe provided inside the housing (not shown) of the load device 3b, and one end is connected to the connection pipe 803b and the other end is connected to the connection pipe 804b. The load-side pipe 301b connects the load-side heat exchanger 31b and the load-side expansion device 32b. Refrigerant flows inside the load-side pipe 301b.

[0139] The load-side heat exchanger 31b, the load-side throttle device 32b, and the load-side fan 33b of the load device 3b of embodiment 7 have the same configurations as the load-side heat exchanger 31, the load-side throttle device 32, and the load-side fan 33 of the load device 3 of embodiment 1. Therefore, detailed description of the load-side heat exchanger 31b, the load-side throttle device 32b, and the load-side fan 33b of the load device 3b of embodiment 7 will be omitted.

[0140] The relay unit 4E has relay pipes 401 to 403, a first bypass pipe 501, and a second bypass pipe 502. The relay unit 4E also has a first bypass-side throttle device 51, a second bypass-side throttle device 52, and on-off valves 48a, 48b, 49a, and 49b.

[0141] One end of the relay pipe 401 is connected to the connection pipe 801, and the other end is connected to the connection pipes 803a and 803b. That is, the relay pipe 401 branches out to correspond to the load devices 3a and 3b. One end of the relay pipe 402 is connected to the connection pipe 805, and the other end is connected to the connection pipes 803b and 804b. That is, the relay pipe 402 branches out to correspond to the load devices 3a and 3b.

[0142] The on-off valve 48a is a valve provided at a branch portion of the relay pipe 401 corresponding to the load device 3a side. The on-off valve 48a switches between an open state that allows the refrigerant to flow through the relay pipe 401 and a closed state that blocks the flow of the refrigerant through the relay pipe 401. The on-off valve 48b is a valve provided at a branch portion of the relay pipe 401 corresponding to the load device 3b side. The on-off valve 48b switches between an open state that allows the refrigerant to flow through the relay pipe 401 and a closed state that blocks the flow of the refrigerant through the relay pipe 401.

[0143] The on-off valve 49a is a valve provided at a branch portion of the relay pipe 402 corresponding to the load device 3a side. The on-off valve 49a switches between an open state that allows the refrigerant to flow through the relay pipe 402 and a closed state that blocks the flow of the refrigerant through the relay pipe 402. The on-off valve 49b is a valve provided at a branch portion of the relay pipe 402 corresponding to the load device 3b side. The on-off valve 49b switches between an open state that allows the refrigerant to flow through the relay pipe 402 and a closed state that blocks the flow of the refrigerant through the relay pipe 402.

[0144] In the following description, when there is no need to distinguish between the load devices 3a and 3b, the suffixes "a" and "b" will be omitted. The same applies to the configurations of the load devices 3a and 3b, and the piping and on-off valves corresponding to the load devices 3a and 3b.

[0145] 20 is a functional block diagram showing a control device 100 according to Embodiment 7. As shown in Fig. 20, the control device 100 is connected wirelessly or by wire to the compressor 21, the flow path switching device 22, the heat source-side blower 24, the load-side expansion device 32, the load-side blower 33, the on-off valves 40 and 41, the first bypass-side expansion device 51, the second bypass-side expansion device 52, the auxiliary-side expansion device 71, and the water pump 91 so as to be able to communicate with each other. Regardless of the operation mode, the control device 100 controls the on-off valves to an open state when blocking the flow of refrigerant to the load device 3.

[0146] (Cooling Operation) Here, the operation of the refrigeration cycle apparatus 1F and the flow of refrigerant will be described using FIG. 19 . Here, only the cooling operation and the heating operation will be described. However, the refrigeration cycle apparatus 1F may be capable of performing a mixed cooling and heating operation in which different operating modes are performed for each load device 3. First, the cooling operation will be described. The control device 100 performs the cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 is connected to the heat source side heat exchanger 23. In the cooling operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state (single-phase) refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the heat source side heat exchanger 23, which functions as a condenser. The refrigerant flowing into the heat source side heat exchanger 23 exchanges heat with the outdoor air sent by the heat source side blower 24, condenses, and becomes a high-temperature, high-pressure two-phase gas-liquid state. The high-temperature, high-pressure refrigerant in a gas-liquid two-phase state flows into the auxiliary heat exchanger 72, which acts as a condenser. The refrigerant that flows into the auxiliary heat exchanger 72 exchanges heat with the heat medium and condenses, becoming a high-pressure liquid. The high-pressure liquid refrigerant is split at the branching point 602, with a portion flowing toward the load device 3 and the remainder flowing through the first bypass pipe 501.

[0147] The high-pressure liquid refrigerant diverted at the branching section 602 and flowing toward the load devices 3 is further diverted at branching sections of the relay pipe 402 corresponding to the load devices 3a and 3b. The refrigerant diverted toward the load devices 3a and 3b then flows into the load-side throttle devices 32a and 32b, where it is decompressed and expanded to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the load-side heat exchangers 31a and 31b, which function as evaporators. The refrigerant that flows into the load-side heat exchangers 31a and 31b exchanges heat with indoor air sent by the load-side fans 33a and 33b, evaporating the liquid phase and becoming a gas (single-phase) refrigerant. At this time, the indoor air is cooled, thereby cooling the room.

[0148] On the other hand, the high-pressure liquid refrigerant branched at the branching portion 602 flows into the first bypass side throttle device 51, where it is decompressed and expanded to become a low-temperature, low-pressure, gas-liquid two-phase refrigerant.

[0149] The low-temperature, low-pressure gas-state refrigerant flowing out of the load-side heat exchangers 31a and 31b of the load devices 3a and 3b merges with the relay pipe 401 at a branch point that branches corresponding to the load devices 3a and 3b. The refrigerant merged at this branch point further merges with the gas-liquid two-phase refrigerant that flowed through the first bypass pipe 501 at a branch point 601. As a result, the refrigerant flowing through the relay pipe 401 becomes a gas-based two-phase refrigerant. The gas-based two-phase refrigerant passes through the flow path switching device 22 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated during the cooling operation of the refrigeration cycle apparatus 1F.

[0150] (Heating Operation) Next, heating operation will be described using FIG. 21 . FIG. 21 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle apparatus 1F according to the seventh embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 is connected to the heat source side heat exchanger 23. During heating operation, the refrigerant drawn into the compressor 21 is compressed by the compressor 21 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and is diverted at branching portions of the relay pipe 401 corresponding to the load devices 3a and 3b. The refrigerant diverted corresponding to the load devices 3a and 3b then flows into the load side heat exchangers 31a and 31b, which function as condensers. The refrigerant flowing into the load side heat exchangers 31a and 31b exchanges heat with indoor air sent by the load side fans 33a and 33b, condensing and becoming a low-temperature liquid. At that time, the indoor air is heated, and heating is performed in the room. The low-temperature, high-pressure liquid refrigerant flowing out from the load-side heat exchangers 31 a and 31 b joins together at branching portions of the relay pipe 402 that branch off corresponding to the load devices 3 a and 3 b. The refrigerant joined at this branching portion is divided at a branching point 603, with a portion flowing toward the auxiliary heat source unit 7 and the remainder flowing through the second bypass pipe 502.

[0151] The low-temperature, high-pressure liquid refrigerant diverted at the branching section 603 and flowing toward the auxiliary heat exchanger 72 is decompressed by the auxiliary-side throttle device 71 to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The low-temperature, low-pressure, two-phase gas-liquid refrigerant flows into the auxiliary heat exchanger 72, which functions as an evaporator. The low-temperature, low-pressure, two-phase gas-liquid refrigerant that has flowed into the auxiliary heat exchanger 72 exchanges heat with a heat medium, evaporating the liquid phase and becoming a gas (single phase).

[0152] On the other hand, the low-temperature, high-pressure liquid refrigerant branched at the branching portion 603 flows into the second bypass side throttle device 52, where it is decompressed and expanded to become low-temperature, low-pressure, gas-liquid two-phase refrigerant.

[0153] The low-temperature, low-pressure gas-state refrigerant flowing out of the auxiliary heat exchanger 72 merges with the gas-liquid two-phase refrigerant flowing through the second bypass pipe 502 at the branch point 604. As a result, the refrigerant flowing through the relay pipe 403 becomes a gas-based two-phase refrigerant. The low-temperature, low-pressure gas-based two-phase refrigerant flows into the heat-source-side heat exchanger 23, which functions as an evaporator. The low-temperature, low-pressure gas-liquid two-phase refrigerant flowing into the heat-source-side heat exchanger 23 exchanges heat with outdoor air supplied by the heat-source-side blower 24, evaporating the liquid phase and becoming low-pressure gas refrigerant (single phase). The low-pressure gas refrigerant flowing out of the heat-source-side heat exchanger 23 passes through the flow switching device 22 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated during heating operation of the refrigeration cycle apparatus 1F.

[0154] As described above, according to the seventh embodiment, similarly to the first embodiment, the throttle device provided in the bypass piping is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger 72 acting as an evaporator or the load-side heat exchanger 31 bypasses the auxiliary heat exchanger 72 or the load-side heat exchanger 31. Therefore, the refrigeration cycle apparatus 1F can suppress a decrease in energy-saving performance.

[0155] Eighth Embodiment Fig. 22 is a refrigerant circuit diagram showing a refrigeration cycle apparatus 1G according to an eighth embodiment. The refrigeration cycle apparatus 1G of the eighth embodiment differs from the refrigeration cycle apparatus 1G of the first embodiment in that, as shown in Fig. 22, the refrigeration cycle apparatus 1G of the eighth embodiment includes a first refrigerant temperature measuring device 67 and a first refrigerant pressure measuring device 68, and performs control to vary the opening degrees of the first bypass side throttle device 51 and the second bypass side throttle device 52 during operation. The following description will focus on the differences from the refrigeration cycle apparatus 1G of the first embodiment, and a description of the commonalities will be omitted.

[0156] Relay unit 4F has a first refrigerant temperature measuring device 67 and a first refrigerant pressure measuring device 68. The first refrigerant temperature measuring device 67 is provided in relay pipe 402 between branching section 602 and the connection position of connection pipe 804. The first refrigerant temperature measuring device 67 measures the temperature of the refrigerant flowing through relay pipe 402. The first refrigerant temperature measuring device 67 transmits the measurement result to control device 100.

[0157] The first refrigerant pressure measuring device 68 is provided in the relay pipe 402 between the branching portion 602 and the connection position of the connection pipe 804. The first refrigerant pressure measuring device 68 measures the pressure of the refrigerant flowing through the relay pipe 402. The first refrigerant pressure measuring device 68 transmits the measurement result to the control device 100.

[0158] FIG. 23 is a functional block diagram showing a control device 100 according to the eighth embodiment. As shown in FIG. 23 , the control device 100 is communicably connected via wires or wirelessly to the first refrigerant temperature measuring device 67, the first refrigerant pressure measuring device 68, the compressor 21, the flow switching device 22, the heat source-side blower 24, the load-side throttle device 32, the load-side blower 33, the on-off valves 40, 41, 48, and 49, the first bypass-side throttle device 51, the second bypass-side throttle device 52, the auxiliary-side throttle device 71, and the water pump 91. During cooling operation, the control device 100 changes the aperture of the first bypass-side throttle device 51 based on the measurement results of the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68. Specifically, the control device 100 calculates the degree of subcooling of the refrigerant from the measurement results of the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68. The control device 100 steadily controls the opening degree of the first bypass side throttle device 51 so that the calculated degree of subcooling falls within a preset control range. Note that the control device 100 may perform control such that the opening degree of the first bypass side throttle device 51 is increased when the calculated degree of subcooling exceeds an upper limit value of the preset control range, and the opening degree of the first bypass side throttle device 51 is decreased when the calculated degree of subcooling exceeds a lower limit value of the preset control range.

[0159] Furthermore, during heating operation, the control device 100 changes the aperture of the second bypass side throttle device 52 based on the measurement results of the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68. Specifically, the control device 100 estimates the phase state of the refrigerant at the inlet of the auxiliary heat source unit 7 from the measurement results of the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68. Then, the control device 100 controls the aperture of the second bypass side throttle device 52 so that the refrigerant is in a liquid state at the inlet of the auxiliary heat source unit 7.

[0160] As described above, according to the eighth embodiment, during cooling operation, the opening degree of the first bypass side throttle device 51 is adjusted so that the degree of subcooling of the refrigerant passing through the relay pipe 402 falls within a preset control range. This suppresses an excessive rise in the condensation saturation temperature of the liquid refrigerant, thereby improving energy-saving performance.

[0161] Furthermore, according to the eighth embodiment, during heating operation, the aperture of the second bypass side throttle device 52 is adjusted so that the refrigerant is in a liquid state at the inlet of the auxiliary heat source unit 7. This reduces the volumetric flow rate of the refrigerant supplied to the auxiliary heat source unit 7 and suppresses excessive supply of refrigerant, thereby reducing the pressure loss from the auxiliary heat exchanger 72 to the branching section 604. This therefore improves energy-saving performance.

[0162] The installation positions of the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68 are not particularly limited. Fig. 24 is a refrigerant circuit diagram showing a refrigeration cycle apparatus 1H according to a modification of Embodiment 8. As shown in Fig. 24, in the relay unit 4G of the refrigeration cycle apparatus 1H, the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68 are provided between the branching portion 602 and the branching portion 603 in the relay pipe 402. Furthermore, it is also possible to perform only control during cooling operation or only control during heating operation based on the measurement results of the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68.

[0163] Ninth embodiment Fig. 25 is a refrigerant circuit diagram showing a refrigeration cycle apparatus 1I according to a ninth embodiment. As shown in Fig. 25, the refrigeration cycle apparatus 1I of the ninth embodiment differs from the refrigeration cycle apparatus 1I of the eighth embodiment in that it has a second refrigerant temperature measuring device 73 and a second refrigerant pressure measuring device 74. The following description will focus on the differences from the refrigeration cycle apparatus 1I of the eighth embodiment, and will omit a description of the commonalities.

[0164] The auxiliary heat source unit 7A has a second refrigerant temperature measuring device 73 and a second refrigerant pressure measuring device 74. The second refrigerant temperature measuring device 73 is provided on the auxiliary heat source side piping 701 between the auxiliary heat exchanger 72 and the connection position of the connection piping 806. The second refrigerant temperature measuring device 73 measures the temperature of the refrigerant flowing through the outlet side of the auxiliary heat exchanger 72 on the auxiliary heat source side piping 701. The second refrigerant temperature measuring device 73 transmits the measurement result to the control device 100.

[0165] The second refrigerant pressure measuring device 74 is provided in the relay pipe 402 between the branching portion 602 and the connection position of the connection pipe 804. The second refrigerant pressure measuring device 74 is provided in the auxiliary heat source side pipe 701 between the connection position of the auxiliary heat exchanger 72 and the connection pipe 806. The second refrigerant pressure measuring device 74 measures the pressure of the refrigerant flowing through the outlet side of the auxiliary heat exchanger 72 in the auxiliary heat source side pipe 701. The second refrigerant pressure measuring device 74 transmits the measurement result to the control device 100.

[0166] 26 is a functional block diagram showing a control device 100 according to a ninth embodiment. As shown in FIG. 26 , the control device 100 is communicably connected via wires or wirelessly to the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68, the second refrigerant temperature measuring device 73 and the second refrigerant pressure measuring device 74, the compressor 21, the flow switching device 22, the heat source side blower 24, the load side expansion device 32, the load side blower 33, the on-off valves 40, 41, 48, and 49, the first bypass side expansion device 51 and the second bypass side expansion device 52, the auxiliary side expansion device 71, and the water pump 91. During heating operation, the control device 100 changes the aperture of the auxiliary side expansion device 71 based on the measurement results of the second refrigerant temperature measuring device 73 and the second refrigerant pressure measuring device 74. Specifically, the control device 100 estimates the phase state of the refrigerant at the outlet of the auxiliary heat source unit 7 from the measurement results of the second refrigerant temperature measuring device 73 and the second refrigerant pressure measuring device 74. The control device 100 then controls the opening degree of the auxiliary-side throttle device 71 so that the refrigerant becomes a superheated gas at the inlet of the auxiliary heat source unit 7 .

[0167] As described above, according to the ninth embodiment, the aperture of the auxiliary-side throttle device 71 is adjusted so that the liquid refrigerant becomes a superheated gas in the auxiliary heat exchanger 72. This improves the heat exchange efficiency in the auxiliary heat exchanger 72. During heating operation, the aperture of the second bypass-side throttle device 52 is adjusted so that the refrigerant becomes a liquid at the inlet of the auxiliary heat source unit 7. That is, liquid refrigerant flows through the second bypass piping 502. Therefore, even when the refrigerant becomes a heated gas in the auxiliary heat exchanger 72, the two-phase gas-liquid refrigerant that has passed through the second bypass-side throttle device 52 provided in the second bypass piping 502 joins the heated gas refrigerant that has passed through the auxiliary heat exchanger 72 at the branching portion 604. This improves the proportion of two-phase gas-liquid refrigerant in the refrigerant flowing from the branching portion 604 to the heat-source-side heat exchanger 23. This improves the energy-saving performance of the refrigeration cycle apparatus 1I.

[0168] The second refrigerant temperature measuring device 73 and the second refrigerant pressure measuring device 74 are not particularly limited as long as they are capable of measuring the temperature and pressure of the refrigerant flowing through the outlet side of the auxiliary heat exchanger 72. For example, they may be provided on any of the piping between the heat source side heat exchanger 23 of the heat source unit 2 and the auxiliary heat exchanger 72 of the auxiliary heat source unit 7.

[0169] The above is a description of the embodiments of the present disclosure. However, the present disclosure is not limited to the configurations of the above embodiments and various modifications are possible within the scope of the technical concept thereof. For example, the heat medium temperature measuring device 93 described in embodiment 6 may be provided in the refrigeration cycle apparatus of other embodiments to perform similar control. Furthermore, in embodiments 2 to 6, multiple load devices 3 may be provided as described in embodiment 7. However, in addition to the load devices 3, multiple auxiliary heat source units 7 may also be provided. Furthermore, the first refrigerant temperature measuring device 67 and the first refrigerant pressure measuring device 68, and the second refrigerant temperature measuring device 73 and the second refrigerant pressure measuring device 74 described in embodiments 8 and 9 may be provided in the refrigeration cycle apparatus of other embodiments to perform similar control.

[0170] The relay unit 4 may be omitted from the refrigeration cycle apparatus 1 of embodiment 1. Even when the heat source unit 2, the load unit 3, and the auxiliary heat source unit 7 are connected without the relay unit 4, the same effect as in embodiment 1 can be obtained by providing a bypass pipe and a bypass-side throttle device and opening the bypass-side throttle device so that a portion of the refrigerant flowing toward the evaporator passes through the bypass pipe.

[0171] 1, 1A to 1I refrigeration cycle device, 2 heat source device, 3 load device, 4, 4A to 4F relay device, 7, 7A auxiliary heat source device, 21 compressor, 22 flow path switching device, 23 heat source side heat exchanger, 24 heat source side blower, 25 accumulator, 26 to 29 check valve, 31, 31a, 31b load side heat exchanger, 32, 32a, 32b load side throttle device, 33, 33a, 33b load side blower, 40 to 49, 48a, 48b, 49a, 49b on / off valve, 51 first bypass side throttle device, 52 second bypass side throttle device, 53 third bypass side throttle device, 54 fourth bypass side throttle device, 55 fifth bypass side throttle device, 61 to 64 check valve, 65 refrigerant heat exchanger, 66 gas-liquid separator, 67 First refrigerant temperature measuring device, 68 First refrigerant pressure measuring device, 71 Auxiliary side throttle device, 72 Auxiliary heat exchanger, 73 Second refrigerant temperature measuring device, 74 Second refrigerant pressure measuring device, 91 Water pump, 92 Tank, 93 Heat medium temperature measuring device, 100 Control device, 101 Processing circuit, 102 Processor, 103 Memory, 104 Bus, 201 to 203 Heat source side piping, 301, 301a, 301b Load side piping, 401 to 417 Relay piping, 501 First bypass piping, 502 Second bypass piping, 503 Third bypass piping, 504 Fourth bypass piping, 505 Fifth bypass piping, 601 to 612 Branching section, 651 First refrigerant flow path, 652 Second refrigerant flow path, 701 Auxiliary heat source side piping, 721 Refrigerant flow path, 722 Heat medium flow path, 801 to 806, 803a, 803b, 804a, 804b: connecting pipe, 901: heat medium pipe.

Claims

1. A refrigeration cycle apparatus comprising a heat source machine, an auxiliary heat source machine, and a load device, wherein the heat source machine, the auxiliary heat source machine, and the load device are connected by a plurality of pipes through which a refrigerant flows, The heat source machine is a compressor that compresses the refrigerant; a heat source side heat exchanger that exchanges heat between the refrigerant and a first fluid, The auxiliary heat source machine is an auxiliary heat exchanger that performs heat exchange between the refrigerant and a second fluid that is thermally independent of the first fluid and has heat derived from renewable energy or waste heat; The load device is a load-side heat exchanger that exchanges heat between the refrigerant and a third fluid that is an object to be heated or cooled; The refrigeration cycle device includes: a relay unit through which the refrigerant flows between the heat source unit, the auxiliary heat source unit, and the load device; a bypass pipe that bypasses one of the auxiliary heat exchanger and the load side heat exchanger that functions as an evaporator; a bypass-side throttle device provided in the bypass piping to reduce the pressure of the refrigerant; a control device for controlling the bypass side throttle device, the bypass piping and the bypass-side throttle device are provided in the relay machine, The control device The bypass-side throttle device is opened so that a portion of the refrigerant flowing toward the auxiliary heat exchanger or the load-side heat exchanger acting as the evaporator passes through the bypass pipe. Refrigeration cycle equipment.

2. A refrigeration cycle device comprising a heat source machine, an auxiliary heat source machine, and a load device, the heat source machine, the auxiliary heat source machine, and the load device being connected by a plurality of pipes through which a refrigerant flows, The heat source machine is a compressor that compresses the refrigerant; a heat source side heat exchanger that exchanges heat between the refrigerant and a first fluid, The auxiliary heat source machine is an auxiliary side throttle device that reduces the pressure of the refrigerant; a second fluid having heat derived from renewable energy or waste heat, the second fluid being thermally independent from the first fluid, and an auxiliary heat exchanger that performs heat exchange between the refrigerant; The load device is a load-side heat exchanger that exchanges heat between the refrigerant and a third fluid that is an object to be heated or cooled; The refrigeration cycle device includes: a second refrigerant temperature measuring device provided between the auxiliary heat source unit and the heat source unit and measuring the temperature of the refrigerant; a second refrigerant pressure measuring device provided between the auxiliary heat source unit and the heat source unit and measuring the pressure of the refrigerant; a bypass pipe that bypasses one of the auxiliary heat exchanger and the load side heat exchanger that functions as an evaporator; a bypass-side throttle device provided in the bypass piping to reduce the pressure of the refrigerant; a control device for controlling the bypass side throttle device, The control device opening the bypass-side throttle device so that a portion of the refrigerant flowing toward the auxiliary heat exchanger or the load-side heat exchanger acting as the evaporator passes through the bypass piping; When the third fluid is heated, the opening degree of the auxiliary-side throttle device is controlled based on the measurement results of the second refrigerant temperature measuring device and the second refrigerant pressure measuring device so that the refrigerant becomes a superheated gas at an outlet of the auxiliary heat source machine. Refrigeration cycle equipment.

3. A refrigeration cycle device comprising a heat source machine, an auxiliary heat source machine, and a load device, the heat source machine, the auxiliary heat source machine, and the load device being connected by a plurality of pipes through which a refrigerant flows, The heat source machine is a compressor that compresses the refrigerant; a heat source side heat exchanger that exchanges heat between the refrigerant and a first fluid, The auxiliary heat source machine is an auxiliary heat exchanger that performs heat exchange between the refrigerant and a second fluid that is thermally independent of the first fluid and has heat derived from renewable energy or waste heat; The load device is a load-side heat exchanger that exchanges heat between the refrigerant and a third fluid that is an object to be heated or cooled; The refrigeration cycle device includes: a first refrigerant temperature measuring device that is provided between the auxiliary heat source unit and the load device and that measures the temperature of the refrigerant; a first refrigerant pressure measuring device provided between the auxiliary heat source unit and the load device, the first refrigerant pressure measuring device measuring the pressure of the refrigerant; a bypass pipe that bypasses one of the auxiliary heat exchanger and the load side heat exchanger that functions as an evaporator; a bypass-side throttle device provided in the bypass piping to reduce the pressure of the refrigerant; a control device for controlling the bypass side throttle device, The control device opening the bypass-side throttle device so that a portion of the refrigerant flowing toward the auxiliary heat exchanger or the load-side heat exchanger acting as the evaporator passes through the bypass piping; When the third fluid is cooled, the opening degree of the bypass-side throttle device is controlled based on the measurement results of the first refrigerant temperature measuring device and the first refrigerant pressure measuring device so that the degree of subcooling of the refrigerant becomes a value within a preset control range. Refrigeration cycle equipment.

4. The control device When the third fluid is heated, the opening degree of the bypass-side throttle device is controlled based on the measurement results of the first refrigerant temperature measuring device and the first refrigerant pressure measuring device so that the refrigerant becomes a liquid refrigerant at the inlet of the auxiliary heat source machine. The refrigeration cycle device according to claim 3.

5. the second fluid is well water; The auxiliary heat exchanger is Heat exchange is performed between the well water and the refrigerant. The refrigeration cycle device according to any one of claims 1 to 4.

6. The bypass piping is a piping that connects a piping through which the refrigerant flows from the auxiliary heat exchanger to the load-side heat exchanger and a piping through which the refrigerant flows from the load-side heat exchanger to the heat source-side heat exchanger when cooling the third fluid. The refrigeration cycle device according to any one of claims 1 to 4.

7. The bypass piping is a piping that connects a piping through which the refrigerant flows from the load-side heat exchanger to the auxiliary heat exchanger and a piping through which the refrigerant flows from the auxiliary heat exchanger to the heat-source-side heat exchanger when the third fluid is heated. The refrigeration cycle device according to any one of claims 1 to 4.

8. The refrigerant is supplied to the bypass duct and the refrigerant is supplied to the bypass duct. The refrigeration cycle device according to any one of claims 1 to 4.