WO2024252473A1 - Refrigeration cycle device - Google Patents

Abstract

This refrigeration cycle device is provided with: a heat source machine having a compressor that compresses a refrigerant, a heat-source-side heat exchanger, and a first flow path switching device that switches a flow path of the refrigerant; a high-pressure-side pipe; a low-pressure-side pipe; a use-side unit connected to the high-pressure-side pipe and the low-pressure-side pipe and having a use-side heat exchanger and a first flow rate control device; a heat medium relay unit connected to the high-pressure-side pipe and the low-pressure-side pipe and having a second flow rate control device and an inter-heat-medium heat exchanger that exchanges heat between the refrigerant and a heat medium that carries heat from an external heat source; a first branch part connected to a first connection pipe extending from each of the use-side unit and the heat medium relay unit; and a second branch part connected to a second connection pipe extending from each of the use-side unit and the heat medium relay unit. The present invention is configured to form, when the heat-source-side heat exchanger functions as an evaporator, such connection that the refrigerant flows from a discharge side of the compressor to the high-pressure-side pipe and such connection that the refrigerant flows from the low-pressure-side pipe to a suction side of the compressor through the heat-source-side heat exchanger. The first branch part is provided with a second flow path switching device that switches the connection between the first connection pipe and the high-pressure-side pipe or the low-pressure-side pipe. The second flow path switching device is configured such that the inter-heat-medium heat exchanger can function as an auxiliary condenser when the heat-source-side heat exchanger functions as a condenser and the inter-heat-medium heat exchanger can function as an auxiliary evaporator when the heat-source-side heat exchanger functions as an evaporator.

Description

Refrigeration Cycle Equipment

This disclosure relates to a refrigeration cycle device capable of multiple operations such as cooling, heating, and hot water supply, and in particular to a refrigeration cycle device that can reduce the load on the heat source side heat exchanger by using unused heat as a heat source.

It has been known that in air conditioning and hot water combined systems that can simultaneously supply cooling loads, heating loads, and hot water loads, including air conditioning and hot water combined systems, the system COP can be improved by balancing the cooling load, heating load, and hot water load (see, for example, Patent Document 1). The refrigeration cycle device disclosed in Patent Document 1 includes a heat source unit, a relay unit connected to the heat source unit by a high-pressure side connection pipe and a low-pressure side connection pipe, and a user side unit including an indoor unit and a hot water heat source circuit. The relay unit has a first distribution section and a second distribution section that are configured so that two connection pipes extending from each user side unit can be selectively connected to the high-pressure side connection pipe or the low-pressure side connection pipe. In Patent Document 1, the first distribution section switches the connection between one connection pipe of each user side unit and the high-pressure side connection pipe or the low-pressure side connection pipe, so that each user side unit can individually perform heating operation, cooling operation, or hot water supply operation. The refrigeration cycle device of Patent Document 1 balances the cooling load, heating load, and hot water load of multiple user units, improving the efficiency of the entire system.

Furthermore, air conditioning systems that use melted snow water or well water are known from the past (see, for example, Patent Document 2). The snow and ice air conditioning system disclosed in Patent Document 2 comprises an indirect outdoor air cooling machine, a compression refrigeration cooling machine, and a snow and ice air conditioning machine. The snow and ice air conditioning machine uses the cold energy of the snowy mountains to cool a refrigerant, which then cools the outdoor air supplied to the heat exchangers on the heat source side of the indirect outdoor air cooling machine and the compression refrigeration cooling machine. The snow and ice air conditioning system of Patent Document 2 makes effective use of the cold energy of the snowy mountains, enabling energy-saving operation.

Patent No. 5642085 JP 2018-146221 A

The refrigeration cycle device disclosed in Patent Document 1 can improve the COP by balancing the cooling load, heating load, and hot water load of the user unit, but the heating and cooling capacity required for the load in the corresponding usage situation of the user unit is borne by the heat source unit. Therefore, no further energy saving effect beyond the improvement of the COP of the refrigeration cycle device can be expected.

The snow and ice air conditioning system disclosed in Patent Document 2 can use the cold energy of snowy mountains to reduce the load on the indirect outdoor air cooler and the compression refrigeration cooler, but the refrigerant circuits of the indirect outdoor air cooler, the compression refrigeration cooler, and the snow and ice cooler are independent. The snow and ice cooler supplies cooled outdoor air to the sensible heat exchanger of the indirect outdoor air cooler and the condenser of the compression refrigeration cooler, and the refrigerant circuits of the indirect outdoor air cooler and the compression refrigeration cooler are also independent, making it difficult to improve the efficiency of the entire system by balancing the load on the two coolers.

This disclosure has been made to solve the problems described above, and provides a refrigeration cycle device that improves COP by balancing the load between each user unit, and enables energy-saving operation of the entire system by utilizing an external heat source.

The refrigeration cycle device according to the present disclosure includes a heat source machine having a compressor for compressing a refrigerant, a heat source side heat exchanger, and a first flow path switching device for switching the flow path of the refrigerant, a high-pressure side pipe through which the refrigerant flows out of the heat source machine, a low-pressure side pipe through which the refrigerant flows into the heat source machine, a utilization side unit connected to the high-pressure side pipe and the low-pressure side pipe and having a utilization side heat exchanger and a first flow control device for controlling the flow rate of the refrigerant flowing to the utilization side heat exchanger, and a utilization side unit connected to the high-pressure side pipe and the low-pressure side pipe. a heat medium relay unit having an intermediate heat exchanger for exchanging heat between the refrigerant and a heat medium carrying heat from an external heat source and a second flow control device for controlling a flow rate of the refrigerant flowing through the intermediate heat exchanger; a first branch unit for branching the high-pressure side piping and the low-pressure side piping to the user side unit and the heat medium relay unit, respectively, and connected to a first connection piping extending from the user side unit and the heat medium relay unit; and a second branch unit for branching the high-pressure side piping and the low-pressure side piping to the user side unit and the heat medium relay unit, respectively, and connected to a second connection piping extending from the user side unit and the heat medium relay unit. and a second branching section, the first flow switching device is configured to connect the refrigerant so that it flows from the discharge side of the compressor through the heat source side heat exchanger to the high-pressure side pipe and from the low-pressure side pipe to the suction side of the compressor when the heat source side heat exchanger functions as a condenser, and to connect the refrigerant so that it flows from the discharge side of the compressor to the high-pressure side pipe and from the low-pressure side pipe to the suction side of the compressor through the heat source side heat exchanger when the heat source side heat exchanger functions as an evaporator, and the first branching section is configured to switch the connection between the first connection pipe and the high-pressure side pipe or the low-pressure side pipe, and the second flow switching device is configured so that the heat medium heat exchanger can function as an auxiliary condenser when the heat source side heat exchanger functions as a condenser, and the heat medium heat exchanger can function as an auxiliary evaporator when the heat source side heat exchanger functions as an evaporator.

According to the present disclosure, by switching the connection of each utilization unit and the heat source side heat exchanger of the heat medium converter using the first branch section and the second branch section, simultaneous heating and cooling operation and hot water supply operation can be performed simultaneously, and the heat medium converter can function to supplement the capacity of the heat source side heat exchanger. Since the heat medium converter is configured to exchange heat with the refrigerant of the refrigeration cycle device using an external heat source such as well water or geothermal heat, and part or all of the capacity of the heat source side heat exchanger can be supplemented by the external heat source, the refrigeration cycle device can be operated in a more energy-efficient manner than before.

1 is a schematic diagram of a configuration of a refrigeration cycle device 100 according to a first embodiment. 1 is an example of a circuit diagram showing a refrigeration cycle device 100 according to a first embodiment. 3 is an explanatory diagram of a flow of a refrigerant when the refrigeration cycle apparatus 100 according to the first embodiment is performing a cooling operation. FIG. FIG. 4 is a diagram showing usage states of heat medium relay units D1, D2 based on temperatures T, t1, and t2 of various parts of the refrigeration cycle apparatus 100 according to the first embodiment. 3 is an explanatory diagram of a flow of a refrigerant when the refrigeration cycle apparatus 100 according to the first embodiment is performing a cooling-dominant operation. FIG. 3 is an explanatory diagram of a flow of a refrigerant when the refrigeration cycle apparatus 100 according to the first embodiment is performing a heating operation. FIG. 3 is an explanatory diagram of a flow of a refrigerant when the refrigeration cycle apparatus 100 according to the first embodiment is performing a heating-dominant operation. FIG. 4 is a flowchart showing an operation of the refrigeration cycle apparatus 100 according to the first embodiment. FIG. 2 is a Mollier diagram of the refrigeration cycle apparatus 100 according to the first embodiment during cooling operation. FIG. 2 is a Mollier diagram of the refrigeration cycle apparatus 100 according to the first embodiment during cooling operation. FIG. 2 is a Mollier diagram of the refrigeration cycle apparatus 100 according to the first embodiment during cooling-dominant operation. FIG. 4 is a Mollier diagram during heating operation of the refrigeration cycle apparatus 100 according to the first embodiment. FIG. 4 is a Mollier diagram during heating operation of the refrigeration cycle apparatus 100 according to the first embodiment. FIG. 4 is a Mollier diagram of the refrigeration cycle apparatus 100 according to the first embodiment during heating-dominated operation. 11 is an example of a circuit diagram showing a refrigeration cycle device 200 according to a second embodiment. FIG. FIG. 11 is a Mollier diagram of the refrigeration cycle apparatus 200 according to the second embodiment during cooling operation. 11 is an example of a circuit diagram showing a refrigeration cycle device 200 according to a second embodiment. FIG. FIG. 11 is a Mollier diagram of the refrigeration cycle apparatus 200 according to the second embodiment during cooling operation. 11 is an example of a circuit diagram showing a refrigeration cycle device 200 according to a second embodiment. FIG. FIG. 11 is a Mollier diagram during heating operation of the refrigeration cycle apparatus 200 according to the second embodiment. 11 is an example of a circuit diagram showing a refrigeration cycle device 200 according to a second embodiment. FIG. FIG. 11 is a Mollier diagram of the refrigeration cycle apparatus 200 according to the second embodiment during heating-dominated operation.

Embodiment 1.
Hereinafter, an embodiment of an air conditioner according to the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a configuration of a refrigeration cycle apparatus 100 according to embodiment 1. As shown in FIG. 1, the refrigeration cycle apparatus 100 includes a heat source unit A, a relay unit B connected to the heat source unit A by a low-pressure side pipe 6 and a high-pressure side pipe 7, and a user side unit C connected to the relay unit B by a first connection pipe 40 and a second connection pipe 41. The user side unit C can select a cooling operation, a heating operation, or a hot water supply operation by using a refrigeration cycle. When the refrigeration cycle apparatus 100 includes a plurality of user side units C, each of the plurality of user side units C can freely select one operation mode from the cooling operation, the heating operation, and the hot water supply operation, and can operate. In other words, the refrigeration cycle apparatus 100 can perform a mixed cooling and heating operation in which a cooling operation and a heating operation are performed simultaneously, and further a mixed operation in which a water boiling operation is also performed.

The heat source unit A and the relay unit B are connected by low-pressure side piping 6 and high-pressure side piping 7, and the refrigerant compressed by the compressor 1 (see Figure 2) of the heat source unit A is sent to the relay unit B, which distributes the refrigerant to each user-side unit C. The operating state of each user-side unit C is changed depending on whether the first connection piping 40 and the second connection piping 41 are connected to the low-pressure side piping 6 or the high-pressure side piping 7. Figure 1 shows, as an example, a case where the topmost user-side unit C1 is in heating operation, the second-highest user-side unit C2 is in cooling operation, and the third-highest user-side unit C3 is in water-boiling operation.

The user side unit C is, for example, an indoor air conditioner or water heater, and is supplied with refrigerant from the repeater B to perform indoor air conditioning or water heating through a refrigeration cycle. Each user side unit C is connected in series to the repeater B and in parallel with each other. In FIG. 1, three user side units C are connected to the repeater B, but this number is not limited, and two or more user side units C may be installed, or there may be only one. In addition, the user side unit C can be an indoor unit of an air conditioner, a water heater, a refrigerator, etc., and there is no limit to the equipment that can be connected.

When the user side unit C is directly connected to the low pressure side pipe 6, the user side heat exchanger 5 (see FIG. 2) functions as an evaporator and performs cooling operation, and when it is directly connected to the high pressure side pipe 7, the user side heat exchanger 5 functions as a condenser and performs heating operation or water boiling operation. The operation of each user side unit C is switched by the second flow path switching device 10c (see FIG. 2) provided in the relay unit B.

The heat medium converter D is further connected to the relay unit B. The heat medium converter D is connected to the relay unit B and is connected in a circuit configuration similar to that of the user unit C. The heat medium converter D also receives refrigerant from the relay unit B, like the user unit C. The heat medium converter D is further connected to an external heat source E. The external heat source E and the heat medium converter D are connected by a circuit in which a heat medium different from the refrigerant flowing from the relay unit B circulates. The heat medium converter D is configured to exchange heat between the heat medium having heat from the external heat source E and the refrigerant that has flowed into the heat medium converter D from the heat source unit A via the relay unit B, and to function as a condenser or evaporator by transferring heat or cold from the external heat source E to the refrigerant. The heat medium converter D may be configured to circulate liquid such as well water from the external heat source E to the heat medium circulation circuit 34 (see FIG. 2), or may be configured to circulate an independent heat medium to the heat medium circulation circuit 34.

In particular, in the first embodiment, the heat medium converter D functions to assist the heat source side heat exchanger 3 (see FIG. 2) of the heat source unit A, and can function as a condenser when the heat source side heat exchanger 3 functions as a condenser, and as an evaporator when the heat source side heat exchanger 3 functions as an evaporator. This allows the heat source side heat exchanger 3 to operate with reduced heat exchange capacity by the amount that the external heat source E is used, and energy savings can be achieved for the refrigeration cycle device 100 as a whole.

The external heat source E connected to the heat medium converter D has heat or cold, such as well water, geothermal heat, or sunlight. The heat medium converter D is a device that transfers the heat or cold of the external heat source E to a refrigerant via a heat medium. When the external heat source E is well water, the well water is pumped up and circulated as a heat medium through the heat medium circulation circuit 34 (see FIG. 2). When geothermal heat is used as the external heat source E, a heat medium such as water heated by geothermal heat circulates through the heat medium circulation circuit 34. When sunlight is used as the external heat source E, a heat medium such as water heated by sunlight circulates through the heat medium circulation circuit 34. Other examples of the external heat source E include ice and snow, melted snow, etc. The external heat source E can also be unused heat such as heat from river water, exhaust gas from equipment, wastewater, and waste heat generated by equipment. The heat medium, such as water, circulating through the heat medium circulation circuit 34 is heat exchanged with the refrigerant circulating through the heat source unit A, etc., in the heat medium heat exchanger 30 (see FIG. 2).

In FIG. 1, multiple heat transfer devices D and external heat sources E are installed, but a single one may be used. In addition, multiple types of heat sources may be used as the external heat source E.

Whether the heat medium converter D is used as an evaporator or a condenser is determined based on whether the temperature of the external heat source E is high or low, based on the evaporation temperature and condensation temperature of the refrigerant in the refrigeration cycle that circulates through the heat source unit A, relay unit B, user unit C, and heat medium converter D. When the temperature of the external heat source E is higher than the evaporation temperature of the refrigerant, the heat medium converter D is used as an evaporator, and when the temperature of the external heat source E is lower than the condensation temperature of the refrigerant, the heat medium converter D is used as a condenser. In general, when a relatively high-temperature external heat source E such as geothermal energy or sunlight is used, the heat medium converter D should be used as an evaporator, and when a relatively low-temperature external heat source E such as well water, snow and ice, or melted snow is used, the heat medium converter D should be used as a condenser.

Depending on the temperature of the external heat source E, the heat medium converter D switches between using the first connection pipe 40 as an evaporator by directly connecting it to the low-pressure side pipe 6, and using the first connection pipe 40 as a condenser by directly connecting it to the high-pressure side pipe 7. Switching of operation using the heat medium converter D is performed by the second flow path switching device 10c (see Figure 2) provided in the relay unit B. Figure 1 shows, as an example, a case where the topmost user side unit C1 is in heating operation, the second user side unit C2 from the top is in cooling operation, and the third user side unit from the top is in water boiling operation.

(Circuit configuration of refrigeration cycle device 100)
2 is an example of a circuit diagram showing the refrigeration cycle apparatus 100 according to the first embodiment. The heat source unit A and the relay unit B are connected by a low-pressure side pipe 6 and a high-pressure side pipe 7. The high-pressure side pipe 7 is a pipe through which the high-pressure refrigerant compressed by the compressor 1 flows out, either directly or via the heat source side heat exchanger 3. The low-pressure side pipe 6 is a pipe through which the low-pressure refrigerant that has passed through the user side unit C or the heat medium converter D flows in, and is a pipe for returning the refrigerant from the relay unit B to the heat source unit A.

The refrigerant in the high-pressure side pipe 7 flows into the high-pressure side branch 10a of the first branch 10 of the relay unit B. The refrigerant in the high-pressure side branch 10a flows into the user unit C or the heat medium converter D by opening the high-pressure side solenoid valves 9c1, 9c2, 9d1, and 9d2 provided in the first branch 10. The high-pressure side solenoid valves 9c1, 9c2, 9d1, and 9d2 may be collectively referred to as the high-pressure side solenoid valves 9.

The low-pressure side pipe 6 is connected to the low-pressure side branch 10b of the first branch 10 of the relay unit B. The refrigerant from the user side unit C or the heat medium converter D flows into the low-pressure side branch 10b by opening the low-pressure side solenoid valves 8c1, 8c2, 8d1, and 8d2. The low-pressure side solenoid valves 8c1, 8c2, 8d1, and 8d2 may be collectively referred to as the low-pressure side solenoid valves 8.

The low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 are connected to first connection pipes 40c1, 40c2, 40d1, and 40d2, which are one of the pipes extending from the utilization side unit C and the heat medium converter D, respectively. The first connection pipes 40c1, 40c2, 40d1, and 40d2 may be collectively referred to as the first connection pipes 40.

The other pipes extending from the user unit C and the heat medium converter D are called second connection pipes 41c1, 41c2, 41d1, and 41d2. The second connection pipes 41c1, 41c2, 41d1, and 41d2 are connected to the second branch 11 of the relay unit. The second connection pipes 41c1, 41c2, 41d1, and 41d2 may be collectively called second connection pipes 41.

By switching the low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 of the first branch section 10 between open and closed, the refrigerant flows from the second branch section 11 to the user side unit C and the heat medium converter D, respectively, or flows from the user side unit C and the heat medium converter D to the second branch section 11.

For example, when the high pressure side solenoid valve 9 is open and the low pressure side solenoid valve 8 is closed, the refrigerant flows from the high pressure side branch 10a connected to the high pressure side pipe 7 through the high pressure side solenoid valve 9 into the user side unit C or the heat medium converter D, and the refrigerant that has passed through the user side unit C or the heat medium converter D flows into the second branch 11.

For example, when the high-pressure side solenoid valve 9 is closed and the low-pressure side solenoid valve 8 is opened, refrigerant that has passed through another user unit C, another heat medium converter D, or refrigerant that has been separated from the high-pressure side piping 7 by the gas-liquid separator 12 and passed through the first heat exchanger 17 and the second heat exchanger 16 flows from the second branch 11 into the user unit C or the heat medium converter D. The refrigerant that has passed through the user unit C or the heat medium converter D passes through the low-pressure side solenoid valve 8 and flows from the low-pressure side branch 10b into the low-pressure side piping 6. The first heat exchanger 17 and the second heat exchanger 16 are sometimes referred to as internal heat exchangers.

As described above, the relay unit B switches the connection state of the utilization side unit C or the heat medium converter D by switching the opening and closing of the low pressure side solenoid valve 8 and the high pressure side solenoid valve 9 of the first branch section 10. This switching allows the utilization side heat exchanger 5 of the utilization side unit C and the heat medium converter 30 of the heat medium converter D to switch between functioning as an evaporator or a condenser, respectively.

The first branching section 10 branches the high-pressure side pipe 7 and the low-pressure side pipe 6 for each of the user side units C and the heat medium converters D, and connects them to the first connection pipe 40, which is one of the pipes extending from each of the user side units C and the heat medium converters D. The first branching section 10 controls whether the first connection pipe 40 of the user side units C and the heat medium converters D is connected to the high-pressure side pipe 7 or the low-pressure side pipe 6 by controlling the high-pressure side solenoid valve 9 and the low-pressure side solenoid valve 8 to close one and open the other. The low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 of the first branching section 10 may be collectively referred to as the second flow path switching device 10c. The second flow path switching device 10c includes the high-pressure side solenoid valve 9 and the low-pressure side solenoid valve 8 provided for each of the user side units C and the heat medium converters D, but is not limited to this form and may be configured as a three-way valve to which the high-pressure side pipe 7, the low-pressure side pipe, and the first connection pipe 40 are connected, for example.

(Heat source machine A)
The heat source unit A is usually placed in a space such as a rooftop outside a building, and supplies cold or hot heat to the user units C1 and C2 via the relay unit B. The heat source unit A is not limited to being placed outdoors, and may be placed in an enclosed space such as a machine room with a ventilation opening. The heat source unit A may also be placed inside a building if the waste heat can be exhausted to the outside of the building through an exhaust duct. Furthermore, the heat source unit A may be placed inside a building as a water-cooled outdoor unit.

The heat source unit A incorporates a compressor 1, a first flow path switching device 2 that switches the refrigerant flow direction of the heat source unit A, a heat source side heat exchanger 3, and an accumulator 29. The compressor 1, the first flow path switching device 2, the heat source side heat exchanger 3, and the accumulator 29 are connected by a low pressure side pipe 6 and a high pressure side pipe 7.

The heat source side heat exchanger 3 is connected in series with the first flow control device 22. In addition, in the heat source unit A, a bypass pipe 25 having a second flow control device 26 is connected in parallel with the heat source side heat exchanger 3. The second flow control device 26 can adjust the flow rate to adjust the amount of refrigerant that bypasses the heat source side heat exchanger 3.

Also, an outdoor flow control device 3m is installed near the heat source side heat exchanger 3 to control the flow rate of a fluid such as outdoor air. In the first embodiment, the outdoor air is sent to the heat source side heat exchanger 3 by the outdoor flow control device 3m, and heat exchange with the refrigerant is performed. The outdoor flow control device 3m is, for example, a fan that sends outdoor air to the heat source side heat exchanger 3. In the first embodiment, an air-cooled outdoor heat exchanger is used as an example of the heat source side heat exchanger 3, and an outdoor fan is used as an example of the outdoor flow control device 3m. Note that the heat source side heat exchanger 3 may be a water-cooled outdoor heat exchanger or the like as long as the refrigerant exchanges heat with another fluid. In this case, a pump is used as the outdoor flow control device 3m. A heat medium such as outdoor air that exchanges heat with the refrigerant in the heat source side heat exchanger 3 may be referred to as a heat source heat medium. Note that, although the first embodiment illustrates a case in which there is one heat source side heat exchanger 3, multiple heat source side heat exchangers 3 may be provided.

The heat source unit A is also provided with a first connection pipe 60a, a second connection pipe 60b, a check valve 18, a check valve 19, a check valve 20, and a check valve 21. Regardless of the connection direction of the first flow path switching device 2, the first connection pipe 60a, the second connection pipe 60b, the check valve 18, the check valve 19, the check valve 20, and the check valve 21 allow high-pressure refrigerant to flow out of the heat source unit A via the high-pressure side pipe 7. The first connection pipe 60a, the second connection pipe 60b, the check valve 18, the check valve 19, the check valve 20, and the check valve 21 allow low-pressure refrigerant to flow into the heat source unit A via the low-pressure side pipe 6.

Compressor 1 draws in the refrigerant and compresses it to a high-temperature, high-pressure state, and is composed of, for example, an inverter compressor with a capacity controllable.

The first flow path switching device 2 switches between the flow of refrigerant during heating operation and the flow of refrigerant during cooling operation. The first flow path switching device 2 switches between two connection states. In one connection state, the first pipe 27 and the bypass pipe 25 are connected to the discharge side of the compressor 1, and the low-pressure side pipe 6 is connected to an accumulator 29 provided on the suction side of the compressor 1. The first pipe 27 is installed in parallel with the bypass pipe 25 and is a pipe leading to the heat source side heat exchanger 3. In the other connection state, the first pipe 27 and the bypass pipe 25 are connected to the accumulator 29 provided on the suction side of the compressor 1, and the discharge side of the compressor 1 is directly connected to the high-pressure side pipe 7.

The first flow path switching device 2 is exemplified as a four-way switching valve. By switching the flow path of the first flow path switching device 2, the heat source side heat exchanger 3 functions as an evaporator during heating operation and as a condenser or radiator during cooling operation.

In the first embodiment, the heat source side heat exchanger 3 exchanges heat between the refrigerant and the outdoor air, evaporating and gasifying the refrigerant or condensing and liquefying the refrigerant. The outdoor flow control device 3m forms an air passage for the air flowing to the heat source side heat exchanger 3. The accumulator 29 is provided on the suction side of the compressor 1, and stores surplus refrigerant due to differences between heating and cooling operations or surplus refrigerant due to transient changes in operation. Note that, although the first embodiment illustrates a case in which one heat source side heat exchanger 3 is provided, multiple heat source side heat exchangers 3 may be connected in parallel.

The check valve 18 is connected to the high-pressure side pipe 7 between the heat source side heat exchanger 3 and the relay unit B, and allows the refrigerant to flow only in the direction from the heat source unit A to the relay unit B. The check valve 19 is provided in the low-pressure side pipe 6 between the relay unit B and the first flow path switching device 2, and allows the refrigerant to flow only in the direction from the relay unit B to the heat source unit A. The check valve 20 is provided in the first connection pipe 60a, and allows the refrigerant discharged from the compressor 1 to flow to the relay unit B during heating operation. The check valve 21 is provided in the second connection pipe 60b, and allows the refrigerant returning from the relay unit B to flow to the suction side of the compressor 1 via the heat source side heat exchanger 3 or the bypass pipe 25 during heating operation.

The first connection pipe 60a connects the low-pressure side pipe 6 between the first flow switching device 2 and the check valve 19 in the heat source unit A, and the high-pressure side pipe 7 between the check valve 18 and the relay unit B. The second connection pipe 60b connects the low-pressure side pipe 6 between the check valve 19 and the relay unit B in the heat source unit A, and the high-pressure side pipe 7 between the heat source side heat exchanger 3 and the check valve 18.

The heat source unit A may also be provided with a discharge pressure gauge 51, a suction pressure gauge 52, a medium pressure pressure gauge 53, and a thermometer 54. The discharge pressure gauge 51 is provided on the discharge side of the compressor 1 and measures the pressure of the refrigerant discharged from the compressor 1. The suction pressure gauge 52 is provided on the suction side of the compressor 1 and measures the pressure of the refrigerant sucked into the compressor 1. The medium pressure pressure gauge 53 is provided upstream of the check valve 18 and measures the medium pressure, which is the pressure of the refrigerant upstream of the check valve 18. The thermometer 54 is provided on the discharge side of the compressor 1 and measures the temperature of the refrigerant discharged from the compressor 1. The pressure information and temperature information detected by the discharge pressure gauge 51, the suction pressure gauge 52, the medium pressure pressure gauge 53, and the thermometer 54 are sent to the control device 50 that controls the operation of the refrigeration cycle device 100, and are used to control each actuator.

The first flow control device 22 is connected in series to the heat source side heat exchanger 3, and is provided between the check valves 21 and 18 and the heat source side heat exchanger 3, and is configured to be freely opened and closed. The first flow control device 22 adjusts the flow rate of refrigerant flowing from the heat source side heat exchanger 3 to the check valve 18 during cooling operation, and adjusts the flow rate of refrigerant flowing from the check valve 21 to the heat source side heat exchanger 3 during heating operation. The first flow control device 22 is configured so that the flow path resistance changes continuously.

The bypass pipe 25 bypasses the heat source side heat exchanger 3. The second flow control device 26 is provided midway through the bypass pipe 25 and is configured to be freely opened and closed, and controls the flow rate of the refrigerant flowing through the bypass pipe 25. The second flow control device 26 adjusts the flow rate of the refrigerant flowing into the heat source side heat exchanger 3. The second flow control device 26 is configured so that the flow path resistance changes continuously.

(Repeater B)
The relay unit B incorporates a first branching section 10, a second branching section 11, a gas-liquid separator 12, a first bypass pipe 14a, a second bypass pipe 14b, a third flow control device 13, a fourth flow control device 15, a first heat exchanger 17, a second heat exchanger 16, and a control device 50. The control device 50 has the same configuration and function as the control device 50 of the heat source unit A.

The first branching section 10 branches the refrigerant flowing in the high-pressure side pipe 7 to the user side unit C and the heat medium converter D. The first branching section 10 also merges the refrigerant flowing in the user side unit C and the heat medium converter D and allows it to flow into the low-pressure side pipe 6. The first branching section 10 includes a low-pressure side solenoid valve 8 and a high-pressure side solenoid valve 9 installed in the first connection pipe 40 of the user side unit C and the heat medium converter D. In other words, the first connection pipe 40 of the user side unit C and the heat medium converter D is branched at the first branching section 10, one of which is connected to the low-pressure side pipe 6 via the low-pressure side solenoid valve 8, and the other of which is connected to the high-pressure side pipe 7 via the high-pressure side solenoid valve 9.

The low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 are controlled to open and close, so that the first connection pipe 40 of the user side unit C and the heat medium converter D can be switched to connect to either the low-pressure side pipe 6 or the high-pressure side pipe 7. The low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 provided in the relay unit B are collectively referred to as the second flow path switching device 10c. The low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 are installed in each pipe where the first connection pipe 40 is branched into two, but they may be configured using, for example, a three-way valve. In other words, other structures may be used as long as the first connection pipe 40 of the user side unit C and the heat medium converter D is configured to connect to either the low-pressure side pipe 6 or the high-pressure side pipe 7. The low-pressure side solenoid valve 8 and the high-pressure side solenoid valve 9 are preferably configured to be closed so that the refrigerant does not flow to any of the user side units C and the heat medium converters D.

The second branch section 11 branches the refrigerant flowing in the first bypass pipe 14a to the user unit C and the heat medium converter D. The second branch section 11 also merges the refrigerant flowing in the user unit C and the heat medium converter D and causes it to flow into the second bypass pipe 14b. The second branch section 11 has a junction between the first bypass pipe 14a and the second bypass pipe 14b.

The gas-liquid separator 12 is provided midway through the high-pressure side pipe 7, and separates the refrigerant that flows in through the high-pressure side pipe 7 into gas and liquid. The gas phase portion separated by the gas-liquid separator 12 flows to the first branch section 10, and the liquid phase portion separated by the gas-liquid separator 12 flows to the second branch section 11.

The first bypass pipe 14a is a pipe that connects the gas-liquid separation device 12 and the second branch 11 in the relay unit B. The second bypass pipe 14b is a pipe that connects the second branch 11 and the low-pressure side pipe 6 in the relay unit B. The third flow control device 13 is provided midway through the first bypass pipe 14a and is configured to be freely opened and closed. The fourth flow control device 15 is provided midway through the second bypass pipe 14b and is configured to be freely opened and closed.

The first heat exchanger 17 exchanges heat between the refrigerant between the gas-liquid separation device 12 and the third flow control device 13 of the first bypass pipe 14a and the refrigerant between the fourth flow control device 15 and the low-pressure side pipe 6 of the second bypass pipe 14b. The second heat exchanger 16 exchanges heat between the refrigerant between the third flow control device 13 and the second branch section 11 of the first bypass pipe 14a and the refrigerant between the fourth flow control device 15 and the first heat exchanger 17 of the second bypass pipe 14b.

(User unit C)
The user side units C are installed at positions where they can supply conditioned air to a space to be air-conditioned, such as a room, and supply cooled air or heated air to the space to be air-conditioned by using cold or hot heat from the heat source unit A supplied via the relay unit B. The user side units C1 and C2 each have a built-in user side heat exchanger 5c1, 5c2 and a first flow control device 4c1, 4c2.

Furthermore, near the user-side heat exchangers 5c1, 5c2, a flow control device 5m is installed to control the flow rate of indoor air, which is a fluid that exchanges heat with the refrigerant. Note that in the first embodiment, an air-cooled user-side heat exchanger is used as an example of the user-side heat exchangers 5c1, 5c2, and an indoor fan is used as an example of the flow control device 5m, but the user-side heat exchanger may be a water-cooled type or other type as long as the refrigerant exchanges heat with another fluid. Furthermore, when a water heater is used as the user-side unit C, the user-side heat exchanger 5 may be a water heat exchanger that exchanges heat between water and the refrigerant. In this case, a pump is used as the flow control device 5m.

Each of the utilization side heat exchangers 5c1 and 5c2 exchanges heat between the air supplied from the flow control device 5m and the refrigerant to generate heated air or cooled air to be supplied to the space to be air-conditioned. The flow control device 5m forms an air path for the air flowing through the utilization side heat exchangers 5c1 and 5c2. The first flow control devices 4c1 and 4c2 are provided between the second branching section 11 of the relay unit B and the utilization side heat exchanger 5c1 or 5c2, and are configured to be freely opened and closed. The first flow control device 4c1 and the first flow control device 4c2 adjust the flow rate of the refrigerant flowing into the utilization side heat exchangers 5c1 and 5c2.

(Heat medium converter D)
The heat medium relay unit D is for supplying heat or cold from an external heat source E to a refrigerant circulating in the refrigeration cycle apparatus 100. The heat medium relay unit D incorporates an inter-heat medium heat exchanger 30 that exchanges heat between the refrigerant circulating in the heat source unit A, the relay unit B, and the user side unit C and a heat medium that carries heat from the external heat source E, and second flow control devices 4d1 and 4d2 that control the flow rate of the refrigerant circulating in the inter-heat medium heat exchanger 30. The second flow control devices 4d1 and 4d2 are provided between the second branching section 11 of the relay unit B and the inter-heat medium heat exchanger 30d1 or 30d2, and are configured to be freely opened and closed. The second flow control devices 4d1 and 4d2 adjust the flow rate of the refrigerant flowing into the inter-heat medium heat exchangers 30d1 and 30d2.

The heat medium is circulated through the heat medium circulation circuit 34 by the pump 31 and sent from the external heat source E to the heat medium-intermediate heat exchanger 30. The heat medium-intermediate heat exchanger 30 is, for example, a plate-type heat exchanger, inside which the refrigerant and heat medium circulate, and the heat or cold of the heat medium is transferred to the refrigerant.

The heat medium converter D is equipped with external heat source temperature sensors 32 and 33. The external heat source temperature sensor 32 detects the temperature of the heat medium flowing into the heat medium heat exchanger 30. The external heat source temperature sensor 33 detects the temperature of the heat medium flowing out of the heat medium heat exchanger 30. Of the multiple heat medium converters D, those connected to external heat sources E with different temperatures may be referred to as a first heat medium converter and a second heat medium converter, respectively.

(External heat source E)
The external heat source E is, for example, well water, melted snow, ice and snow, geothermal heat, solar light, etc., and the heat medium can be changed appropriately depending on the target heat source. For example, when the external heat source E is well water stored in a large amount in a well underground, the well water is pumped up by a pump 31 to become a heat medium, and is caused to flow into the heat medium heat exchanger 30 by a heat medium circulation circuit 34. The well water exchanges heat with the refrigerant, flows out of the heat medium heat exchanger 30, and its temperature increases. The well water with the increased temperature is returned to the well. The well water that serves as the external heat source E is stored in a large amount underground, and even if the temperature increases through the heat medium converter D and the water resistance is returned, the temperature of the external heat source E hardly changes.

The heat medium circulation circuit 34 may be configured to circulate an independent heat medium in the heat medium circulation circuit 34. As shown in FIG. 2, the heat medium circulation circuit 34 may be connected to an external heat exchanger F that exchanges heat between the external heat source E and the heat medium flowing through the heat medium circulation circuit 34. The external heat exchanger F exchanges heat between the heat medium and the external heat source E. The heat medium that has been heat exchanged in the external heat exchanger F is sent to the heat medium-to-heat medium heat exchanger 30 and is heat exchanged with the refrigerant circulating through the refrigerant circuit of the refrigeration cycle device 100. By configuring in this way, the quality of the heat medium flowing through the heat medium circulation circuit 34 can be maintained, and the durability of the heat medium circulation circuit 34 and the heat medium converter D can be ensured, as opposed to pumping up well water as the heat medium, for example. The configuration of the heat medium circulation circuit 34 may be changed as appropriate depending on what is used as the external heat source E.

When geothermal energy is used as the external heat source E, piping through which a heat medium such as water circulates is extended into the ground, and the geothermal energy is transferred to the heat medium. When sunlight is used as the external heat source E, piping through which a heat medium such as water circulates is connected to a solar water heater or the like, and the heat from the sunlight is transferred to the heat medium. The refrigeration cycle device 100 according to the first embodiment makes effective use of such an external heat source E to achieve energy savings.

As shown in FIG. 2, the heat medium converters D1 and D2 can be installed in parallel on the relay unit B, so that multiple external heat sources E can be used for the refrigeration cycle device 100. For example, when the refrigeration cycle device 100 performs cooling operation or cooling-dominated operation, the heat source side heat exchanger 3 functions as a condenser, and the heat medium converter D1 using the well water as the external heat source E1 also functions as a condenser, so that the capacity of the heat source side heat exchanger 3 during cooling operation or cooling-dominated operation can be supplemented by the heat medium converter D1. Also, when the refrigeration cycle device 100 performs heating operation or heating-dominated operation, the heat source side heat exchanger 3 functions as an evaporator, and the heat medium converter D2 using sunlight as the external heat source E2 also functions as an evaporator, so that the capacity of the heat source side heat exchanger 3 during heating operation or heating-dominated operation can be supplemented by the heat medium converter D2.

The refrigeration cycle apparatus 100 according to the first embodiment can appropriately select the operating state of the multiple user side units C from cooling, heating, and water heating operation by switching the connection between the heat source unit A and the user side units C using the second flow path switching device 10c, thereby enabling simultaneous cooling and heating operation. In addition, the refrigeration cycle apparatus 100 can appropriately switch the external heat source E to be used as an auxiliary for the heat source side heat exchanger 3 or as a substitute for the heat source side heat exchanger 3 by switching the connection state with the multiple heat medium converters D using the second flow path switching device 10c.

(Control device 50)
The refrigeration cycle apparatus 100 is provided with a control device 50. The control device 50 controls actuators and the like based on refrigerant pressure information, refrigerant and heat medium temperature information, outdoor temperature information, indoor temperature information, and the like detected by each sensor provided in the refrigeration cycle apparatus 100. For example, the control device 50 controls driving of the compressor 1, switching between the first flow path switching device 2 and the second flow path switching device 10c, driving of the fan motor of the outdoor flow control device 3m, driving of the fan motor of the flow control device 5m, and the pump 31 that sends the heat medium to the heat source side heat exchanger 3.

The control device 50 controls the opening of the first flow control device 22, the second flow control device 26, the third flow control device 13, and the fourth flow control device 15. The control device 50 includes a memory 50a in which information for determining each control value is stored. The control device 50 may be configured with hardware such as a control circuit that realizes its functions. The control device 50 may be configured with a software program stored in a storage unit such as a semiconductor memory, and a computing device such as a microcomputer or a CPU (central processing unit) that executes the software program. In the first embodiment, the control device 50 is provided in the heat source unit A and the relay unit B, but the number of control devices 50 may be one or three or more. The control device 50 may be provided in the user unit C or the heat medium converter D, or may be provided as a separate unit in a location other than the heat source unit A, the relay unit B, the user unit C, and the heat medium converter D.

(Driving mode)
Next, a description will be given of various operation modes performed by the refrigeration cycle apparatus 100. The operation modes of the refrigeration cycle apparatus 100 include four modes: cooling operation, heating operation, cooling-dominated operation, and heating-dominated operation.

Cooling operation is an operation mode in which all user side units C are in cooling operation or stopped. Heating operation is an operation mode in which all user side units C are in heating operation or stopped. Cooling-dominated operation is an operation mode in which heating or cooling can be selected for each indoor unit, and the cooling load is greater than the heating load. Cooling-dominated operation is an operation mode in which the heat source side heat exchanger 3 is connected to the discharge side of the compressor 1 and acts as a condenser. Heating-dominated operation is an operation mode in which heating or cooling can be selected for each indoor unit, and the heating load is greater than the cooling load. Heating-dominated operation is an operation mode in which the heat source side heat exchanger 3 is connected to the suction side of the compressor 1 and acts as an evaporator.

(Cooling operation)
3 is an explanatory diagram of the flow of refrigerant when the refrigeration cycle apparatus 100 according to the first embodiment is in cooling operation. A case of cooling operation in which all of the user side units C1 and C2 perform cooling will be described. When the cooling operation is performed, the control device 50 switches the first flow path switching device 2 so that the refrigerant discharged from the compressor 1 flows to the heat source side heat exchanger 3. In addition, the low pressure side solenoid valves 8c1 and 8c2 connected to the user side units C1 and C2 are opened, and the high pressure side solenoid valves 9c1 and 9c2 are closed.

In this state, compressor 1 starts operating. The low-temperature, low-pressure gaseous refrigerant is compressed by compressor 1 and discharged as high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from compressor 1 flows into heat source side heat exchanger 3 via first flow switching device 2. At this time, the refrigerant is cooled while heating the outdoor air, becoming medium-temperature, high-pressure liquid refrigerant or gas-liquid two-phase refrigerant. The medium-temperature, high-pressure refrigerant flowing out of heat source side heat exchanger 3 passes through high-pressure side piping 7 and is separated in gas-liquid separation device 12.

The liquid refrigerant separated by the gas-liquid separator 12 passes through the first bypass pipe 14a, exchanges heat with the refrigerant flowing through the second bypass pipe 14b in the first heat exchanger 17, passes through the third flow control device 13, exchanges heat with the refrigerant flowing through the second bypass pipe 14b in the second heat exchanger 16, is cooled, and flows into the second branch section 11.

A portion of the refrigerant that flows into the second branch 11 is bypassed to the second bypass piping 14b, and the remainder flows into the second connecting piping 41c1, 41c2 of the user side units C1, C2. The high-pressure liquid or gas-liquid two-phase refrigerant branched at the second branch 11 flows through the second connecting piping 41c1, 41c2 and flows into the first flow control devices 4c1, 4c2 of the user side units C1, C2. The high-pressure liquid refrigerant is then throttled and expanded by the first flow control devices 4c1, 4c2, reducing the pressure and becoming a low-temperature, low-pressure, two-phase gas-liquid state. The change in the refrigerant at the first flow control devices 4c1, 4c2 is carried out under a constant enthalpy. The low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows out of the first flow control devices 4c1, 4c2 flows into the user side heat exchangers 5c1, 5c2. The refrigerant then heats up while cooling the indoor air, becoming a low-temperature, low-pressure gaseous refrigerant.

The low-temperature, low-pressure gaseous refrigerant flowing out of the user-side heat exchangers 5c1 and 5c2 passes through the low-pressure solenoid valves 8c1 and 8c2, respectively, and flows into the low-pressure branch 10b of the first branch 10. The low-temperature, low-pressure gaseous refrigerant that joins in the low-pressure branch 10b also joins with the low-temperature, low-pressure gaseous refrigerant that has been heated in the first heat exchanger 17 and the second heat exchanger 16 of the second bypass piping 14b, passes through the low-pressure piping 6 and the first flow switching device 2, and flows into the compressor 1, where it is compressed.

When the heat medium relays D1, D2 are connected to the refrigeration cycle device 100, it is determined whether or not to use the heat medium relays D1, D2 based on the magnitude relationship between the temperatures t1, t2 of the external heat sources E1, E2 and the temperature T flowing into the heat source side heat exchanger 3. Note that with regard to the external heat source temperature sensor 32 that measures the temperatures t1, t2 of the external heat sources E1, E2, the one installed in one of the heat medium relays D1 and D2 may be referred to as the first external heat source temperature sensor, and the other may be referred to as the second external heat source temperature sensor.

4 is a diagram showing the use state of the heat medium converters D1 and D2 based on the temperatures T, t1, and t2 of each part of the refrigeration cycle apparatus 100 according to the first embodiment. The temperature T is the temperature of the outside air sent to the heat source side heat exchanger 3, the temperature t1 is the temperature of the heat medium flowing into the heat medium heat exchanger 30d1 of the heat medium converter D1, and the temperature t2 is the temperature of the heat medium flowing into the heat medium heat exchanger 30d2 of the heat medium converter D2. When the refrigeration cycle apparatus 100 is performing cooling operation, the heat medium converters D1 and D2 are used when the heat medium temperatures t1 and t2 are lower than the temperature T of the outside air flowing into the heat source side heat exchanger 3. The temperature T is measured by a temperature sensor 3t installed near the heat source side heat exchanger 3. The temperature t1 is measured by an external heat source temperature sensor 32 installed upstream of the heat medium heat exchanger 30d1 of the heat medium circulation circuit 34 of the heat medium converter D1. Temperature t2 is measured by an external heat source temperature sensor 32 installed upstream of the intermediate heat exchanger 30d2 in the heat medium circulation circuit 34 of the heat medium converter D2.

As an example, FIG. 3 shows the flow of the refrigerant in the case of No. 1 or No. 2 in FIG. 4. In the state of No. 1 and No. 2 in FIG. 4, the temperatures t1 and t2 of the heat medium are lower than the temperature T of the outside air flowing into the heat source side heat exchanger 3. In this case, the refrigeration cycle device 100 uses both the heat medium converters D1 and D2 to assist the heat source side heat exchanger 3, which is a condenser.

The medium-temperature, high-pressure liquid refrigerant flowing out of the heat source-side heat exchanger 3 passes through the high-pressure-side pipe 7 and is separated in the gas-liquid separator 12. The separated gas refrigerant flows into the high-pressure-side branch 10a. The high-pressure-side solenoid valves 9d1, 9d2 connected to the heat medium converters D1 and D2 are opened, and the low-pressure-side solenoid valves 8d1, 8d2 are closed. The gas refrigerant in the high-pressure-side branch 10a flows through the first connection pipes 40d1, 40d2 into the heat medium-to-heat medium heat exchangers 30d1, 30d2.

The gas refrigerant that flows into the heat medium heat exchangers 30d1, 30d2 is condensed by heat exchange with the low-temperature heat medium, becoming a high-pressure, low-temperature liquid or gas-liquid two-phase refrigerant. The high-pressure, low-temperature refrigerant is throttled and expanded by the second flow control devices 4d1, 4d2, reducing its pressure and becoming a low-temperature, low-pressure, gas-liquid two-phase state. The refrigerant that flows out of the second flow control devices 4d1, 4d2 flows into the second branch section 11, where it is mixed with the refrigerant that flows into the second branch section 11 from the gas-liquid separator 12 via the first bypass piping 14a, and flows into the user side units C1, C2.

In particular, in the state No. 1 in FIG. 4, when comparing the temperature t1 of the heat medium circulating through the heat medium converter D1 with the temperature t2 of the heat medium circulating through the heat medium converter D2, the temperature t1 of the heat medium circulating through the heat medium converter D1 is higher. In other words, the temperature relationship is T>t1>t2. In this case, the control device 50 controls the pump 31 so that more heat medium circulates through the intermediate heat exchanger 30d2 of the heat medium converter D2, which has a lower heat medium temperature. The control device 50 may also adjust the second flow control device 4d2 to increase the amount of refrigerant sent to the heat medium converter D2.

In this way, in the cooling operation of the refrigeration cycle device 100, not only the heat source side heat exchanger 3 is used as a condenser, but also the heat medium converters D1 and D2 can be used as condensers. Therefore, in the heat source unit A, the output of the outdoor flow control device 3m that blows air to the heat source side heat exchanger 3 can be reduced, or a part of the refrigerant discharged from the compressor 1 can be sent from the bypass pipe 25 to the high pressure side pipe 7. The refrigerant that does not pass through the heat source side heat exchanger 3 but passes through the bypass pipe 25 flows from the gas-liquid separator 12 into the high pressure side branch section 10a, and flows into the heat medium heat exchangers 30d1 and 30d2 and is condensed. In this way, the heat medium converters D1 and D2 can complement the capacity of the heat source side heat exchanger 3 by using the external heat sources E1 and E2.

Also, depending on the capacity of the heat medium converters D1 and D2, it is possible to prevent the refrigerant from flowing to the heat source side heat exchanger 3 in the heat source unit A, and to have all the refrigerant flow to the high pressure side pipe 7 via the bypass pipe 25. The high pressure refrigerant is separated into liquid refrigerant and gas refrigerant in the gas-liquid separator 12. The gas refrigerant flows into the heat medium converters D1 and D2 via the high pressure side branch section 10a, exchanges heat with the heat medium, and is condensed. The refrigerant that has become a low temperature, high pressure liquid or gas-liquid two-phase refrigerant is then decompressed by the flow control devices 4d1, 4d2, 4c1, and 4c2, flows into the user side heat exchangers 5c1 and 5c2, exchanges heat with the indoor air, etc., and expands, thereby cooling the room. In this way, the heat medium converters D1 and D2 can function as a substitute for the heat source side heat exchanger 3 by using the external heat sources E1 and E2.

In cooling operation in the state No. 1 shown in FIG. 4, since the temperature t2 of the heat medium circulating through the heat medium relay unit D2 is the lowest, the control unit 50 maximizes the flow rate of the pump 31 of the heat medium relay unit D2, making it greater than the flow rate of the pump 31 of the heat medium relay unit D1. This allows more cold heat from the external heat source E2, which is effective as a heat source that can be used for the condenser, to be utilized. The flow rate of the refrigerant flowing through the heat medium relay units D1 and D2 can also be appropriately adjusted using the high-pressure side solenoid valves 9d1 and 9d2. When the heat source side heat exchanger 3 is not used, the outdoor flow rate control unit 3m can be stopped.

In addition, in the state No. 2 shown in FIG. 4, the temperatures t1 and t2 of the heat medium circulating through the heat medium converters D1 and D2 are both lower than the outside air temperature T, but the temperature t1 of the heat medium circulating through the heat medium converter D1 is lower than the temperature t2 of the heat medium circulating through the heat medium converter D2. When multiple heat medium converters D1 and D2 are used, during cooling operation, it is advisable to increase the flow rate of the pump 31 of the heat medium converter D connected to the external heat source E with a lower temperature, thereby enhancing the capacity of the heat medium converter D as a condenser.

In addition, in the states No. 3 and No. 5 shown in FIG. 4, one of the temperatures t1 and t2 of the heat medium circulating through the heat medium relay units D1 and D2 is lower than the outside air temperature T, but the other is higher than the temperature T. In such a case, only the heat medium relay unit D1 or D2 in which a heat medium with a temperature lower than the outside air temperature T is used, and in the heat medium relay unit D1 or D2 in which a heat medium with a temperature higher than the outside air temperature T is circulated, both the low-pressure side solenoid valve 8d and the high-pressure side solenoid valve 9d are closed, or the second flow control device 4d is closed, so that the refrigerant does not circulate.

Furthermore, in the states No. 4 and No. 6 shown in FIG. 4, both temperatures t1 and t2 of the heat medium circulating through the heat medium relay units D1 and D2 are higher than the outside air temperature T. In this case, the refrigeration cycle device 100 operates without using the heat medium relay units D1 and D2 and without relying on the external heat source E.

When multiple heat medium converters D are connected to the refrigeration cycle apparatus 100, in cooling operation, as shown in FIG. 4, the heat medium converter D in which the temperature of the circulating heat medium is lower than the temperature T of the outside air flowing into the heat source side heat exchanger 3 is used. In the first embodiment, the refrigeration cycle apparatus 100 has two heat medium converters D connected to the relay unit B, but more heat medium converters D may be connected. The number of the multiple heat medium converters D through which the refrigerant flows can be adjusted as appropriate according to the capacity of the heat source side heat exchanger 3 and the amount of heat required for the user side unit C.

(Cooling-dominant operation)
FIG. 5 is an explanatory diagram of the flow of the refrigerant when the refrigeration cycle device 100 according to the first embodiment is in cooling-dominant operation. Here, as an example of the cooling-dominant operation, a case where the user side unit C1 is cooling and the user side unit C2 is heating will be described. The user side unit C1 in which the user side heat exchanger 5c1 functions as an evaporator may be called the first unit, and the user side unit C2 in which the user side heat exchanger 5c2 functions as a condenser may be called the second unit. The cooling-dominant operation is an operation mode in which cooling or heating can be selected for each indoor unit, and the cooling load is larger than the heating load. The cooling-dominant operation is an operation mode in which the heat source side heat exchanger 3 is connected to the discharge side of the compressor 1 and acts as a condenser. In this case, the control device 50 switches the first flow path switching device 2 so that the refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3, similar to the cooling operation.

In this state, the compressor 1 is operated, and the low-temperature, low-pressure gaseous refrigerant is compressed by the compressor 1 and discharged as high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 flows into the heat source side heat exchanger 3 via the first flow switching device 2. Alternatively, some or all of the gaseous refrigerant discharged from the compressor 1 may pass through the bypass piping 25. At this time, the heat amount required for heating may be secured by the refrigerant passing through the bypass piping 25, or the refrigerant may be condensed in the heat source side heat exchanger 3, leaving the heat amount required for heating. The refrigerant that has passed through the heat source side heat exchanger 3 and the bypass piping 25 is in a medium-temperature, high-pressure gas-liquid two-phase state.

The medium-temperature, high-pressure two-phase gas-liquid refrigerant passes through the high-pressure side pipe 7 and flows into the gas-liquid separation device 12. In the gas-liquid separation device 12, it is separated into gaseous refrigerant and liquid refrigerant. The gaseous refrigerant separated in the gas-liquid separation device 12 flows from the high-pressure side branch 10a of the first branch 10 through the high-pressure side solenoid valve 9c2 into the user-side heat exchanger 5c2 that performs heating. The refrigerant is then cooled while heating the indoor air, becoming a medium-temperature, high-pressure liquid refrigerant. The refrigerant flowing out of the user-side heat exchanger 5c2 that performs heating passes through the first flow control device 4c2 and flows into the second branch 11.

Meanwhile, the liquid refrigerant separated by the gas-liquid separator 12 flows into the first heat exchanger 17 and is cooled by heat exchange with the low-pressure refrigerant flowing through the second bypass pipe 14b. The refrigerant flowing out of the first heat exchanger 17 passes through the third flow control device 13 and the second heat exchanger 16 and flows into the second branch section 11.

Part of the liquid refrigerant that joins at the second branch 11 is bypassed to the second bypass pipe 14b, and the remainder flows into the first flow control device 4c1 provided in the user unit C1 that performs cooling. The high-pressure liquid refrigerant is throttled and expanded by the first flow control device 4c1, reducing its pressure and becoming a low-temperature, low-pressure two-phase gas-liquid state. The change in the refrigerant in the first flow control device 4c1 occurs under constant enthalpy.

The low-temperature, low-pressure two-phase gas-liquid refrigerant flowing out of the first flow control device 4c1 flows into the user-side heat exchanger 5c1, which performs cooling. The refrigerant is heated while cooling the indoor air, and becomes a low-temperature, low-pressure gaseous refrigerant. The low-temperature, low-pressure gaseous refrigerant flowing out of the user-side heat exchanger 5c1 passes through the low-pressure side solenoid valve 8c1 and flows into the low-pressure side branch section 10b. The low-temperature, low-pressure gaseous refrigerant that flows into the low-pressure side branch section 10b via the user-side heat exchanger 5c1 merges with the low-temperature, low-pressure gaseous refrigerant heated in the first heat exchanger 17 and the second heat exchanger 16 of the second bypass piping 14b, flows into the compressor 1 through the low-pressure side piping 6 and the first flow switching device 2, and is compressed.

In cooling-dominated operation, just like in cooling operation, if heat medium relays D1 and D2 are connected to the refrigeration cycle device 100, it is determined whether to use the heat medium relays D1 and D2 based on the magnitude relationship between the temperatures t1 and t2 of the external heat sources E1 and E2 and the temperature T flowing into the heat source side heat exchanger 3.

As shown in Figure 4, in cooling-dominated operation, just as in cooling operation, when the heat medium temperatures t1 and t2 are lower than the temperature T of the outside air flowing into the heat source-side heat exchanger 3, the heat medium relays D1 and D2 are used. In refrigerant-dominated operation, the heat medium relays D1 and D2 are used in the same way as in cooling operation.

In FIG. 5, as an example, the flow of the refrigerant in the cases of No. 1 and No. 2 in FIG. 4 is shown. The flow rate of the pump 31 of the heat medium relay units D1 and D2 is adjusted in the same way as in cooling operation as shown in FIG. 4. In addition, the heat medium relay units D1 and D2 can appropriately control whether or not to circulate the refrigerant by operating the low-pressure side solenoid valves 8d1 and 8d2, the high-pressure side solenoid valves 9d1 and 9d2, and the second flow control devices 4d1 and 4d2.

(Heating operation)
6 is an explanatory diagram of the flow of refrigerant when the refrigeration cycle apparatus 100 according to the first embodiment is in heating operation. A case will be described in which both the utilization side units C1 and C2 are performing heating. When the heating operation is performed, the control device 50 switches the first flow path switching device 2 so that the refrigerant discharged from the compressor 1 flows directly into the high pressure side pipe 7 and the first branch portion 10.

In this state, the compressor 1 is operated, and the low-temperature, low-pressure gaseous refrigerant is compressed by the compressor 1 and discharged as high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 flows into the high-pressure side branch 10a of the first branch 10 via the first flow switching device 2 and the high-pressure side piping 7. The high-temperature, high-pressure gaseous refrigerant that flows into the high-pressure side branch 10a is branched, passes through the high-pressure side solenoid valves 9c1, 9c2, and flows into the user side heat exchangers 5c1, 5c2. The refrigerant is then heated while cooling the indoor air, becoming a medium-temperature, high-pressure liquid refrigerant.

The medium-temperature, high-pressure liquid refrigerant flowing out of the user-side heat exchangers 5c1, 5c2 flows into the first flow control devices 4c1, 4c2. The refrigerant expands and is decompressed in the first flow control devices 4c1, 4c2, becoming a medium-temperature, medium-pressure two-phase gas-liquid refrigerant, which merges at the second branch section 11. The refrigerant that flows into the second branch section 11 flows into the second bypass pipe 14b or the heat medium converters D1, D2.

A portion of the refrigerant that flows into the second branch 11 flows from the second bypass pipe 14b through the fourth flow control device 15 into the low-pressure branch 10b of the first branch 10. In addition, a portion of the refrigerant that flows into the second branch 11 flows into the heat medium converters D1 and D2. The refrigerant that flows into the heat medium converters D1 and D2 is expanded and decompressed in the second flow control devices 4d1 and 4d2 to be medium-temperature and medium-pressure, and then exchanges heat with the heat medium from the external heat sources E1 and E2 in the heat medium heat exchangers 30d1 and 30d2, evaporating, becoming a low-temperature, low-pressure gas refrigerant that flows into the low-pressure branch 10b of the first branch 10.

The refrigerant that joins at the low-pressure side branch 10b passes through the low-pressure side piping 6 and flows into the first flow control device 22, where it becomes a low-temperature, low-pressure, two-phase gas-liquid state, and is heated while cooling the outdoor air in the heat source side heat exchanger 3, becoming a low-temperature, low-pressure gaseous refrigerant. Note that if the refrigerant that has entered the low-pressure side piping 6 has become a sufficiently low-temperature, low-pressure gaseous refrigerant, it may be sent to the suction side of the compressor 1 via the bypass piping 25 without passing through the heat source side heat exchanger 3.

Also, the entire refrigerant that flows into the second branch section 11 from the user side units C1, C2 performing heating operation may be made to flow into the heat medium converters D1, D2. In this way, the entire amount of refrigerant can be evaporated using the external heat sources E1, E2, reducing the load on the heat source side heat exchanger 3 and leading to energy savings. Also, if the entire amount of refrigerant can be sufficiently converted into low temperature and low pressure gas refrigerant in the heat medium converters D1, D2, the refrigeration cycle apparatus 100 may not use the outdoor flow control device 3m or may cause the refrigerant to be sucked into the compressor 1 without using the heat source side heat exchanger 3.

In FIG. 6, the flow of the refrigerant in the cases of No. 4 and No. 6 in FIG. 4 is shown as an example. In the state of No. 4 in FIG. 4, the temperatures t1 and t2 of the heat medium are higher than the temperature T of the outside air flowing into the heat source side heat exchanger 3, and when comparing the temperature t1 of the heat medium circulating through the heat medium converter D1 with the temperature t2 of the heat medium circulating through the heat medium converter D2, the temperature t1 of the heat medium circulating through the heat medium converter D1 is higher. In other words, the temperature relationship is t1>t2>T. In this case, the control device 50 controls the pump 31 so that more heat medium circulates through the heat medium heat exchanger 30d1 of the heat medium converter D1, which has a higher heat medium temperature. The control device 50 may also adjust the second flow control device 4d1 to increase the amount of refrigerant sent to the heat medium converter D1.

In addition, in the heating operation in the state No. 4 shown in FIG. 4, since the temperature t1 of the heat medium circulating through the heat medium relay unit D1 is the highest, the control unit 50 maximizes the flow rate of the pump 31 of the heat medium relay unit D1, making it greater than the flow rate of the pump 31 of the heat medium relay unit D2. This allows the refrigeration cycle device 100 to utilize more heat from the external heat source E1, which is effective as a heat source that can be used as an evaporator. The flow rate of the refrigerant flowing through the heat medium relay units D1 and D2 may also be appropriately adjusted using the high-pressure side solenoid valves 9d1 and 9d2. In addition, when the refrigerant is in a state in which it is acceptable for the refrigerant to be drawn into the compressor 1 without using the heat source side heat exchanger 3, the outdoor flow rate control unit 3m may be stopped.

In the heating operation in the state No. 6 shown in FIG. 4, the relationship between the outside air temperature T, the temperature t1 of the heat medium circulating through the heat medium converter D1, and the temperature t2 of the heat medium circulating through the heat medium converter D2 is t2>t1>T. In the heating operation in the state No. 6, the temperature t2 of the heat medium circulating through the heat medium converter D2 is the highest, so the control device 50 maximizes the flow rate of the pump 31 of the heat medium converter D2, making it greater than the flow rate of the pump 31 of the heat medium converter D1. In this way, when the refrigeration cycle device 100 uses multiple heat medium converters D1 and D2, it is preferable to increase the flow rate of the pump 31 of the heat medium converter D connected to the external heat source E with a higher temperature in the heating operation, thereby enhancing the capacity of the heat medium converter D as an evaporator.

In addition, in the states No. 3 and No. 5 shown in FIG. 4, one of the temperatures t1 and t2 of the heat medium circulating through the heat medium relay units D1 and D2 is higher than the outside air temperature T, but the other is lower than the temperature T. In such a case, only the heat medium relay unit D1 or D2 in which a heat medium with a temperature higher than the outside air temperature T is used, and in the heat medium relay unit D1 or D2 in which a heat medium with a temperature lower than the outside air temperature T is circulated, both the low-pressure side solenoid valve 8d and the high-pressure side solenoid valve 9d are closed, or the second flow control device 4d is closed, so that the refrigerant does not circulate.

In addition, in the states No. 1 and No. 2 shown in FIG. 4, both temperatures t1 and t2 of the heat medium circulating through the heat medium relay units D1 and D2 are lower than the outside air temperature T. In this case, the refrigeration cycle device 100 does not use the heat medium relay units D1 and D2, and operates without relying on the external heat source E.

When multiple heat medium converters D are connected to the refrigeration cycle apparatus 100, in heating operation, as shown in FIG. 4, the heat medium converters D in which the temperatures t1 and t2 of the circulating heat medium are higher than the temperature T of the outside air flowing into the heat source side heat exchanger 3 are used. In the first embodiment, the refrigeration cycle apparatus 100 has two heat medium converters D connected to the relay unit B, but more heat medium converters D may be connected. The number of the multiple heat medium converters D through which the refrigerant flows can be adjusted as appropriate according to the capacity of the heat source side heat exchanger 3 and the amount of heat required for the user side unit C.

(Heating-dominant operation)
FIG. 7 is an explanatory diagram of the flow of the refrigerant when the refrigeration cycle device 100 according to the first embodiment is in heating-dominated operation. Here, as an example of the heating-dominated operation, a case where the user-side unit C1 is in heating operation and the user-side unit C2 is in cooling operation as shown in FIG. 7 will be described. The heating-dominated operation is an operation mode in which heating or cooling can be selected for each indoor unit, and the heating load is larger than the cooling load. The heating-dominated operation is an operation mode in which the heat source-side heat exchanger 3 is connected to the suction side of the compressor 1 and acts as an evaporator. In this case, the control device 50 switches the first flow path switching device 2 so that the refrigerant discharged from the compressor 1 flows directly into the high-pressure side pipe 7 and the first branch portion 10, as in the heating operation.

In this case, the control device 50 switches the first flow path switching device 2 so that the refrigerant discharged from the compressor 1 flows into the first branch section 10. In addition, the low-pressure side solenoid valve 8c1 connected to the utilization side unit C1 is closed, and the high-pressure side solenoid valve 9c1 is opened.

In this state, the compressor 1 is operated, and the low-temperature, low-pressure gaseous refrigerant is compressed by the compressor 1 and discharged as high-temperature, high-pressure gaseous refrigerant. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor 1 flows into the high-pressure side pipe 7 via the first flow path switching device 2.

The medium-temperature, high-pressure two-phase gas-liquid refrigerant passes through the high-pressure piping 7 and flows into the gas-liquid separator 12, where it is separated into gaseous refrigerant and liquid refrigerant. The gaseous refrigerant separated in the gas-liquid separator 12 flows from the high-pressure branch 10a of the first branch 10 through the high-pressure solenoid valve 9c1 into the user-side heat exchanger 5c1 that performs heating. The refrigerant is then cooled while heating the indoor air, becoming a medium-temperature, high-pressure liquid refrigerant. The refrigerant flowing out of the user-side heat exchanger 5c1 that performs heating passes through the first flow control device 4c1 and flows into the second branch 11.

Meanwhile, the liquid refrigerant separated by the gas-liquid separator 12 flows into the first bypass pipe 14a and is cooled by heat exchange with the low-pressure refrigerant flowing through the second bypass pipe 14b in the first heat exchanger 17. The refrigerant flowing out of the first heat exchanger 17 passes through the third flow control device 13 and the second heat exchanger 16 and flows into the second branch section 11.

A portion of the refrigerant that has passed through the first bypass pipe 14a or the user side unit C1, which joins at the second branch 11, is bypassed to the second bypass pipe 14b, and the remainder flows into the first flow control device 4c2 provided in the user side unit C2 that performs cooling. The refrigerant that has flowed into the user side unit C2 is throttled and expanded by the first flow control device 4c2, reducing its pressure and becoming a low-temperature, low-pressure, gas-liquid two-phase state. The change in the refrigerant in the first flow control device 4c2 is carried out under constant enthalpy.

The low-temperature, low-pressure two-phase gas-liquid refrigerant flowing out of the first flow control device 4c2 flows into the user-side heat exchanger 5c2, which performs cooling. The refrigerant is heated while cooling the indoor air, and becomes a low-temperature, low-pressure gaseous refrigerant. The low-temperature, low-pressure gaseous refrigerant flowing out of the user-side heat exchanger 5c1 passes through the low-pressure solenoid valve 8c2 and flows into the low-pressure branch 10b. The low-temperature, low-pressure gaseous refrigerant that flows into the low-pressure branch 10b merges with the low-temperature, low-pressure gaseous refrigerant heated in the first heat exchanger 17 and the second heat exchanger 16 of the second bypass piping 14b, passes through the low-pressure piping 6, flows into the compressor 1 through the heat source side heat exchanger 3 or the bypass piping 25, and is compressed.

In heating-dominated operation, just like in heating operation, if heat medium converters D1 and D2 are connected to the refrigeration cycle device 100, it is determined whether to use the heat medium converters D1 and D2 based on the magnitude relationship between the temperatures t1 and t2 of the external heat sources E1 and E2 and the temperature T flowing into the heat source side heat exchanger 3.

As shown in Figure 4, even in heating-dominated operation, when the temperatures t1 and t2 of the heat medium are higher than the temperature T of the outside air flowing into the heat source-side heat exchanger 3, the heat medium converters D1 and D2 are used. In heating-dominated operation, the heat medium converters D1 and D2 are used in the same way as in heating operation.

In FIG. 7, as an example, the flow of the refrigerant in the cases of No. 4 and No. 6 in FIG. 4 is shown. The flow rate of the pump 31 of the heat medium relay units D1 and D2 is adjusted in the same way as in heating operation as shown in FIG. 4. In addition, the heat medium relay units D1 and D2 can appropriately control whether or not to allow the refrigerant to flow by operating the low pressure side solenoid valve 8d, the high pressure side solenoid valve 9d, and the second flow control device 4d.

(Control of the refrigeration cycle device 100)
FIG. 8 is a flowchart showing the operation of the refrigeration cycle apparatus 100 according to the first embodiment. Here, a control flow for determining in what state the heat medium relay unit D is to be operated during the operation of the refrigeration cycle apparatus 100 will be described. As shown in FIG. 8, during the operation of the refrigeration cycle apparatus 100, first, it is confirmed which operation mode the refrigeration cycle apparatus 100 is in. Since the heat medium relay unit D assists the heat source side heat exchanger 3, it is sufficient to first confirm whether the heat source side heat exchanger 3 is operated as a condenser or an evaporator. In step A1, the control device 50 determines whether the operation is cooling operation and cooling-dominated operation (step A2) or heating operation and heating-dominated operation (step A7).

Next, the control device 50 acquires the temperature T of the outside air or other heat medium flowing into the heat source side heat exchanger 3, and the temperatures t1 and t2 of the heat medium flowing into the heat medium-intermediate heat exchanger 30 of the heat medium converter D (steps A3 and A8). The temperature T of the outside air or other heat medium flowing into the heat source side heat exchanger 3 is temperature data measured by, for example, a temperature sensor 3t. The temperatures t1 and t2 of the heat medium flowing into the heat medium-intermediate heat exchanger 30 of the heat medium converter D are temperature data measured by, for example, an external heat source temperature sensor 32 in the heat medium circulation circuit 34 where the heat medium flows into the heat medium-intermediate heat exchanger 30.

When the refrigeration cycle device 100 is in cooling operation or cooling-dominant operation (step A2), the control device 50 compares the measurement results of the temperature T of the heat source side temperature sensor and the temperatures t1, t2 of the heat medium converter temperature sensor (step A3) and determines whether the condition T > t1, t2 is satisfied (step A4).

The control device 50 controls the heat medium converter D that satisfies the above condition T>t1, t2 to operate as a condenser (step A5). For the heat medium converter D that satisfies the condition, the second flow switching device 10c is operated to control the refrigerant to be sent and the flow rate of the heat medium circulation circuit 34 is adjusted. The flow rate of the heat medium circulation circuit 34 is adjusted, for example, by comparing the temperatures measured by the external heat source temperature sensor 32 on the upstream side of the heat medium heat exchanger 30 and the external heat source temperature sensor 33 on the downstream side, and increasing the flow rate of the pump 31 when the difference between the measured temperatures is greater than a predetermined value.

The control device 50 basically controls the heat medium exchange between the refrigerant and the heat medium for the heat medium relay device D that does not satisfy the above conditions T>t1, t2 (step A6). The control device 50 operates the second flow switching device 10c so that the refrigerant does not flow into the heat medium relay device D that does not satisfy the conditions. The control device 50 also stops the pump 31 of the heat medium circulation circuit 34 of the heat medium relay device D that does not satisfy the conditions. However, even if the conditions T>t1, t2 are not satisfied, if the capacity of the heat source side heat exchanger 3 is insufficient, the heat medium relay device D that does not satisfy the conditions T>t1, t2 may be used. In other words, if there is a heat medium relay device D that does not satisfy the conditions T>t1, t2 (No in step A4), the control device 50 determines whether the capacity of the heat source side heat exchanger 3 as a condenser is sufficient (step A11). If the capacity of the heat source side heat exchanger 3 is insufficient (Yes in step A11), the control device 50 may control the heat medium exchanger D that does not satisfy the conditions to be used (step A12).

When the refrigeration cycle device 100 is in heating operation or heating-dominant operation (step A7), the control device 50 compares the measurement results of the temperature T of the heat source side temperature sensor and the temperatures t1, t2 of the heat medium converter temperature sensor (step A8) and determines whether the condition T<t1, t2 is satisfied (step A9).

The control device 50 controls the heat medium converter D that satisfies the above condition T<t1, t2 to operate as an evaporator (step A10). For the heat medium converter D that satisfies the condition, the second flow switching device 10c is operated to control the refrigerant to be sent and the flow rate of the heat medium circulation circuit 34 is adjusted. The flow rate of the heat medium circulation circuit 34 is adjusted, for example, by comparing the temperatures measured by the external heat source temperature sensor 32 on the upstream side of the heat medium heat exchanger 30 and the external heat source temperature sensor 33 on the downstream side, and increasing the flow rate of the pump 31 when the difference between the measured temperatures is greater than a predetermined value.

The control device 50 also basically controls the heat medium relay unit D that does not satisfy the above conditions T<t1, t2 so that heat exchange between the refrigerant and the heat medium does not occur (step A6). However, even if the conditions T>t1, t2 are not satisfied, if the capacity of the heat source side heat exchanger 3 is insufficient, the heat medium relay unit D that does not satisfy the conditions T>t1, t2 may be used (steps A11 and A12). This is the same as for the cooling operation and the cooling-dominated operation.

In steps A4 and A9, if there are multiple heat medium reactors D that meet the conditions, the temperatures t1 and t2 of the heat medium circulating through the heat medium reactors D may be compared, and the flow rate of the circulating heat medium may be controlled as shown in FIG. 4. In addition, the flow rate of the refrigerant flowing into the heat medium reactor D may be adjusted according to the temperatures t1 and t2 of the heat medium circulating through the heat medium reactor D.

(Function of the refrigeration cycle device 100)
As described above, the refrigeration cycle apparatus 100 according to the first embodiment can operate in four modes, namely, cooling operation, cooling-dominated operation, heating operation, and heating-dominated operation, using the utilization side units C. The refrigeration cycle apparatus 100 has a plurality of utilization side units C, and each utilization side heat exchanger 5 can be used as a condenser or an evaporator, enabling simultaneous cooling and heating operation. The refrigeration cycle apparatus 100 also includes a heat medium converter D, which can be used as a condenser or an evaporator by switching the refrigerant flow path in the same manner as the utilization side units C, and can be used to supplement or complement the heat source side heat exchanger 3.

9 and 10 are Mollier diagrams of the refrigeration cycle device 100 according to the first embodiment during cooling operation. As shown in FIG. 9, during cooling operation, the heat source side heat exchanger 3 functions as a condenser, and the user side heat exchanger 5 of the user side unit C functions as an evaporator. The user side heat exchanger 5 shown in FIG. 9 is not limited to a single one, and may be multiple. The refrigerant condensed in the heat source side heat exchanger 3 is decompressed by a flow control device 4, which is an expander, and evaporates in the user side heat exchangers 5 of the user side units C1 and C2, and is sucked into the compressor 1. The refrigeration cycle device 100 performs a heat pump cycle by utilizing the heat released in the heat source side heat exchanger 3 and the heat absorbed by the user side heat exchangers 5c1 and 5c2.

The Mollier diagram shown in FIG. 10 shows the state of the refrigeration cycle device 100 shown in FIG. 3, in which the intermediate heat exchangers 30d1 and 30d2 are directly connected to the heat source heat exchanger 3. As a result, the intermediate heat exchangers 30d1 and 30d2 become auxiliary condensers and function as one condenser together with the heat source heat exchanger 3. The intermediate heat exchangers 30d1 and 30d2 are connected in parallel to each other, but they may be connected in series. In this case, it is preferable to provide a refrigerant pipe that flows from the heat medium converter D1 to D2. Specifically, it is preferable to provide a path that allows the refrigerant to flow from the second connection pipe 41d1 of the heat medium converter D1 in FIG. 3 to the first connection pipe 40d2 of the heat medium converter D2. This allows the heat medium converters D1 and D2 to be used to more efficiently supercool the refrigerant.

11 is a Mollier diagram of the refrigeration cycle apparatus 100 according to the first embodiment during cooling-dominated operation. The Mollier diagram shown in FIG. 11 shows the state of the refrigeration cycle apparatus 100 shown in FIG. 5, in which the intermediate heat exchangers 30d1 and 30d2 and the user-side heat exchanger 5c2 in heating operation are connected in series to the heat source-side heat exchanger 3 and function as a condenser. The intermediate heat exchangers 30d1 and 30d2 and the user-side heat exchanger 5c2 in heating operation are connected in parallel to each other. The intermediate heat exchangers 30d1 and 30d2 and the user-side heat exchanger 5c2 in heating operation may be connected in series. In this case, it is preferable to provide a refrigerant pipe that allows the refrigerant to flow between the user-side unit C2 and the heat medium converters D1 and D2.

12 and 13 are Mollier diagrams of the refrigeration cycle device 100 according to the first embodiment during heating operation. As shown in FIG. 12, during heating operation, the user side heat exchangers 5c1 and 5c2 function as condensers, and the heat source side heat exchanger 3 functions as an evaporator. The user side heat exchanger 5 shown in FIG. 12 is not limited to multiple, and may be a single one. The refrigerant condensed in the user side heat exchanger 5 of the user side units C1 and C2 is decompressed in the expander, evaporated in the heat source side heat exchanger 3, and sucked into the compressor 1. In the refrigeration cycle device 100, the refrigeration cycle is performed by the heat radiation in the user side heat exchangers 5c1 and 5c2 and the heat absorption in the heat source side heat exchanger 3.

The Mollier diagram shown in FIG. 13 shows the state of the refrigeration cycle device 100 shown in FIG. 6, in which the user-side heat exchangers 5c1 and 5c2 are directly connected to the discharge side (high pressure side) of the compressor 1. As a result, the user-side heat exchangers 5c1 and 5c2 function as condensers and perform heating operation. The refrigerant that flows out of the user-side heat exchangers 5c1 and 5c2 is decompressed by the first flow control devices 4c1 and 4c2 and flows into the intermediate heat exchangers 30d1 and 30d2. The intermediate heat exchangers 30d1 and 30d2 are connected in series with the heat source-side heat exchanger 3 and function as an evaporator together with the heat source-side heat exchanger 3. The intermediate heat exchangers 30d1 and 30d2 are connected in parallel to each other, but may be connected in series. In this case, it is preferable to provide a refrigerant pipe that flows from the heat medium converter D1 to the heat medium converter D2. This allows the refrigerant to be superheated more efficiently using the heat transfer media converters D1 and D2.

14 is a Mollier diagram of the refrigeration cycle device 100 according to the first embodiment during heating-dominated operation. The Mollier diagram shown in FIG. 14 shows the state of the refrigeration cycle device 100 shown in FIG. 7, in which the discharge side of the compressor 1 is directly connected to the user-side heat exchanger 5c1 performing heating operation. The user-side heat exchanger 5c1 functions as a condenser and cools the refrigerant while heating the air in the room. The refrigerant that flows out of the user-side heat exchanger 5c1 is decompressed in the expander and flows into the user-side heat exchanger 5c2 performing cooling operation and the heat medium heat exchangers 30d1 and 30d2. In addition, the user-side heat exchanger 5c2 and the heat medium heat exchangers 30d1 and 30d2 are directly connected to the heat source-side heat exchanger 3. As a result, the heat medium heat exchangers 30d1 and 30d2 function as auxiliary evaporators and function as an evaporator together with the heat source-side heat exchanger 3.

The refrigeration cycle device 100 according to embodiment 1 can improve the efficiency of the entire system by balancing the cooling load of the user unit C with the heating load and hot water load, and can also balance the load of the user unit C with the load of the heat source unit A by supplying heat from an external heat source E to assist the heat source side heat exchanger 3. The refrigeration cycle device 100 can reduce the load of the heat source unit A by supplying heat from the external heat source E, achieving energy savings overall.

Embodiment 2.
The refrigeration cycle apparatus 200 according to the second embodiment is obtained by changing the connection of the plurality of heat medium relay units D1, D2 of the refrigeration cycle apparatus 100 according to the first embodiment. The following mainly describes the differences between the second embodiment and the first embodiment.

In the refrigeration cycle device 100 according to the first embodiment, a configuration has been described in which multiple heat medium converters D1 and D2 are connected in parallel to each other in the refrigerant circuit, but in the refrigeration cycle device 200 according to the second embodiment, multiple heat medium converters D1 and D2 are configured so that they can be connected in series to each other.

FIG. 15 is an example of a circuit diagram showing a refrigeration cycle apparatus 200 according to the second embodiment. The refrigeration cycle apparatus 200 is configured such that, of the two heat medium relay units D1 and D2, the refrigerant that has passed through one of the heat medium relay units D1 further passes through the other heat medium relay unit D2. Specifically, the refrigeration cycle apparatus 200 has a connection pipe 71 that connects the second connection pipe 41d1 of one of the heat medium relay units D1 and the first connection pipe 40d2 of the other heat medium relay unit D2. The second connection pipe 41d1 is provided with, for example, a three-way valve 70.

(Cooling operation)
15 shows a case where the refrigeration cycle apparatus 200 is in cooling operation. The refrigeration cycle apparatus 200 is configured such that, during cooling operation, the refrigerant flowing from the high-pressure side branch 10a of the first branch 10 into the relay unit D1 passes through the connecting pipe 71 and flows into the relay unit D2. The refrigerant flowing from the intermediate heat exchanger 30d1 of the relay unit D1 through the three-way valve 70 and the connecting pipe 71 and passing through the relay unit D2 flows into the second branch 11. The refrigerant flowing into the second branch 11 flows into the user side units C1 and C2 and is evaporated, similarly to the cooling operation in the first embodiment.

Fig. 16 is a Mollier diagram of the refrigeration cycle apparatus 200 according to the second embodiment during cooling operation. The refrigeration cycle apparatus 200 shown in Fig. 15 is connected so that the refrigerant from the heat source side heat exchanger 3 flows into the heat medium heat exchangers 30d1 and 30d2 through the first branch section 10, and the heat medium heat exchangers 30d1 and 30d2 are connected in series with each other. As a result, the heat medium heat exchangers 30d1 and 30d2 become auxiliary condensers and function together with the heat source side heat exchanger 3 as if they were one condenser.

(Cooling-dominant operation)
Fig. 17 is an example of a circuit diagram showing the refrigeration cycle apparatus 200 according to the second embodiment. Fig. 17 shows a case where the refrigeration cycle apparatus 200 is in cooling-dominant operation. Even in cooling-dominant operation, the refrigeration cycle apparatus 200 is configured so that the refrigerant that has passed through the relay unit D1 passes through the connecting pipe 71 and flows into the relay unit D2. The refrigerant that has passed through the relay unit D1 via the three-way valve 70 and the connecting pipe 71 and the relay unit D2 flows into the second branch section 11. The refrigerant that has flowed into the second branch section 11 joins with the refrigerant condensed in the user-side unit C2 as in the cooling operation according to the first embodiment, flows into the user-side unit C1, and is evaporated.

Fig. 18 is a Mollier diagram of the refrigeration cycle apparatus 200 according to the second embodiment during cooling operation. In the refrigeration cycle apparatus 200 shown in Fig. 17, the intermediate heat exchangers 30d1 and 30d2 are connected in series with each other, and the user-side heat exchanger 5c2 performing heating operation is connected in parallel to the intermediate heat exchangers 30d1 and 30d2. The intermediate heat exchangers 30d1 and 30d2 and the user-side heat exchanger 5c2 are each connected so that the refrigerant from the heat source-side heat exchanger 3 flows in through the first branch portion 10, and function as a condenser.

(Heating operation)
FIG. 19 is an example of a circuit diagram showing a refrigeration cycle apparatus 200 according to the second embodiment. FIG. 19 shows a case where the refrigeration cycle apparatus 200 is in heating operation. The refrigeration cycle apparatus 200 is configured such that, during heating operation, the refrigerant that has passed through the relay unit D2 passes through the connecting pipe 71 and flows into the relay unit D1. The refrigerant that has flowed into the user side units C1 and C2 from the high-pressure side branch 10a of the first branch 10 is condensed and flows into the second branch 11. The refrigerant that has flowed into the second branch 11 flows into the relay units D1 and D2 and is evaporated, as in the heating operation according to the first embodiment. Specifically, the refrigerant flows into the relay unit D2 from the second branch 11, passes through the relay unit D1 via the connecting pipe 71 and the three-way valve 70, and flows into the low-pressure side branch 10b of the first branch 10.

Figure 20 is a Mollier diagram of the refrigeration cycle apparatus 200 according to embodiment 2 during heating operation. In the refrigeration cycle apparatus 200 shown in Figure 19, the utilization side heat exchangers 5c1 and 5c2 are connected so that the refrigerant flowing out from the discharge side (high pressure side) of the compressor 1 flows in through the high pressure side branch 10a. As a result, the utilization side heat exchangers 5c1 and 5c2 function as condensers, and the utilization side units C1 and C2 perform heating operation. The refrigerant flowing out of the utilization side heat exchangers 5c1 and 5c2 is decompressed by the first flow control devices 4c1 and 4c2 and flows into the second branch 11. The refrigerant flowing into the second branch 11 first flows into the heat medium heat exchanger 30d2, and then flows into the heat medium heat exchanger 30d1. The refrigeration cycle device 200 shown in FIG. 19 is configured so that the refrigerant that has passed through the heat medium heat exchangers 30d1 and 30d2 flows into the heat source side heat exchanger 3 through the low pressure side branch section 10b, and the heat medium heat exchangers 30d1 and 30d2 are connected in series to each other. The heat medium heat exchangers 30d1 and 30d2 function as auxiliary evaporators and function together with the heat source side heat exchanger 3 as if they were one evaporator.

(Heating-dominant operation)
FIG. 21 is an example of a circuit diagram showing a refrigeration cycle apparatus 200 according to the second embodiment. FIG. 21 shows a case where the refrigeration cycle apparatus 200 is in heating-dominant operation. In the heating-dominant operation, the refrigeration cycle apparatus 200 is configured such that the refrigerant that has passed through the heat medium relay unit D2 passes through the connection pipe 71 and flows into the heat medium relay unit D1. In the heating-dominant operation, the refrigerant that has flowed from the high-pressure side branch 10a of the first branch 10 into the user-side unit C1 performing heating operation is condensed and flows into the second branch 11. The refrigerant that has flowed into the second branch 11 flows into the user-side unit C2 performing cooling operation, the heat medium relay units D1 and D2, and is evaporated, as in the heating-dominant operation in the first embodiment. Specifically, the refrigerant flows from the second branch 11 into the user-side unit C2 and the heat medium relay unit D2. The refrigerant that has flowed into the relay unit D2 passes through the connecting pipe 71 and the three-way valve 70 and then through the relay unit D1, and flows into the low-pressure branch 10b of the first branch 10.

FIG. 22 is a Mollier diagram of the refrigeration cycle apparatus 200 according to the second embodiment during heating-dominated operation. In the refrigeration cycle apparatus 200 shown in FIG. 22, the intermediate heat exchangers 30d1 and 30d2 are connected in series with each other, and the user-side heat exchanger 5c2 in cooling operation is connected in parallel to the intermediate heat exchangers 30d1 and 30d2. The intermediate heat exchangers 30d1 and 30d2 and the user-side heat exchanger 5c2 are each connected in series to the heat source-side heat exchanger 3 and function as an evaporator. The intermediate heat exchangers 30d1 and 30d2 serve as auxiliary evaporators and function together with the heat source-side heat exchanger 3 as if they were a single evaporator.

Although not shown in Fig. 15 and Fig. 17, the refrigeration cycle apparatus 200 may further include a connection pipe that connects the second connection pipe 41d2 of one heat medium converter D2 to the first connection pipe 40d1 of the other heat medium converter D2 so that the refrigerant flows from the heat medium converter D2 to the heat medium converter D1. Similarly, in Fig. 19 and Fig. 21, the refrigeration cycle apparatus 200 may further include a connection pipe that connects the second connection pipe 41d2 of one heat medium converter D1 to the first connection pipe 40d1 of the other heat medium converter D2 so that the refrigerant flows from the heat medium converter D1 to the heat medium converter D2. This makes it possible to reverse the order of the intermediate heat exchangers 30d1 and 30d2 that cool or heat the refrigerant in the Mollier diagrams shown in Figs. 16, 18, 20, and 22. The control device 50 may control the order in which the refrigerant flows through the heat medium heat exchangers 30d1 and 30d2, for example, depending on the temperatures of the external heat sources E1 and E2.

In addition, in Figures 15, 17, 19, and 21, the two heat medium relay units D1 and D2 are connected using a three-way valve 70 and a connecting pipe 71, but this is not limited to the configuration. The refrigerant circuit may have a different structure as long as it is configured to flow refrigerant sequentially through the two heat medium relay units D1 and D2. For example, the three-way valve 70 may be realized by combining valves and connecting pipes of other structures. In addition, the refrigerant circuit connecting the heat medium relay units D1 and D2 may be provided inside the relay unit B or externally.

As described above, the first and second embodiments of the present disclosure have been described. However, the first and second embodiments are merely examples of the refrigeration cycle devices 100 and 200, and may be combined with other known technologies. Furthermore, the refrigeration cycle devices 100 and 200 may have parts of their configuration omitted or modified without departing from the gist of the present disclosure. In short, the refrigeration cycle devices 100 and 200 include the range of design modifications and application variations that would normally be made by a person skilled in the art, without departing from the technical concept thereof.

1 compressor, 2 first flow switching device, 3 heat source side heat exchanger, 3m outdoor flow control device, 3t temperature sensor, 4 flow control device, 4c1 (first) flow control device, 4c2 (first) flow control device, 4d1 (second) flow control device, 4d2 (second) flow control device, 5 utilization side heat exchanger, 5c1 utilization side heat exchanger, 5c2 utilization side heat exchanger, 5d1 heat medium heat exchanger, 5m flow control device, 6 low pressure side piping, 7 high pressure side piping, 8 low pressure side solenoid valve, 8c1 low pressure side solenoid valve, 8c2 low pressure side solenoid valve, 8d low pressure side solenoid valve, 8d1 low pressure side solenoid valve , 8d2 low pressure side solenoid valve, 9 high pressure side solenoid valve, 9c1 high pressure side solenoid valve, 9c2 high pressure side solenoid valve, 9d high pressure side solenoid valve, 9d1 high pressure side solenoid valve, 9d2 high pressure side solenoid valve, 10 first branch, 10a high pressure side branch, 10b low pressure side branch, 10c second flow path switching device, 11 second branch, 12 gas-liquid separation device, 13 third flow control device, 14a first bypass piping, 14b second bypass piping, 15 fourth flow control device, 16 second heat exchanger, 17 first heat exchanger, 18 check valve, 19 check valve, 20 check valve, 21 check valve, 22 first Flow control device, 25 bypass piping, 26 second flow control device, 27 first piping, 29 accumulator, 30 intermediate heat exchanger, 30d1 intermediate heat exchanger, 30d2 intermediate heat exchanger, 31 pump, 32 external heat source temperature sensor, 33 external heat source temperature sensor, 34 heat medium circulation circuit, 40 first connection piping, 40c1 first connection piping, 40c2 first connection piping, 40d1 first connection piping, 40d2 first connection piping, 41 second connection piping, 41c1 second connection piping, 41c2 second connection piping, 41d1 second connection piping, 41d2 second connection piping 1 connecting pipe, 50 control device, 50a memory, 51 discharge pressure gauge, 52 suction pressure gauge, 53 medium pressure gauge, 54 thermometer, 60a first connecting pipe, 60b second connecting pipe, 70 three-way valve, 71 connecting pipe, 100 refrigeration cycle device, 200 refrigeration cycle device, A heat source device, B relay device, C user unit, C1 user unit, C2 user unit, C3 user unit, D heat medium converter, D1 heat medium converter, D2 heat medium converter, E external heat source, E1 external heat source, E2 external heat source, T temperature, t1 temperature, t2 temperature.

Claims (16)

A heat source unit including a compressor that compresses a refrigerant, a heat source side heat exchanger, and a first flow path switching device that switches a flow path of the refrigerant;
A high-pressure side pipe through which the refrigerant flows out of the heat source unit;
A low-pressure side pipe through which the refrigerant flows into the heat source unit;
a utilization side unit connected to the high pressure side pipe and the low pressure side pipe, the utilization side unit including a first flow control device for controlling a flow rate of the refrigerant flowing through the utilization side heat exchanger;
a heat medium converter connected to the high-pressure side piping and the low-pressure side piping, the heat medium converter including an intermediate heat exchanger for exchanging heat between the refrigerant and a heat medium carrying heat from an external heat source, and a second flow control device for controlling a flow rate of the refrigerant flowing through the intermediate heat exchanger;
a first branching section that branches the high pressure side piping and the low pressure side piping to the utilization side unit and the heat medium relay unit, respectively, and is connected to a first connection piping extending from the utilization side unit and the heat medium relay unit, respectively;
a second branch portion connected to a second connection pipe extending from each of the utilization side unit and the heat medium relay unit,
The first flow path switching device is
When the heat source side heat exchanger functions as a condenser, the refrigerant is connected so as to flow from the discharge side of the compressor through the heat source side heat exchanger to the high pressure side pipe, and the refrigerant is connected so as to flow from the low pressure side pipe to the suction side of the compressor,
When the heat source side heat exchanger functions as an evaporator, the refrigerant is connected to flow from the discharge side of the compressor to the high pressure side pipe, and the refrigerant is connected to flow from the low pressure side pipe to the suction side of the compressor via the heat source side heat exchanger,
The first branch portion is
A second flow path switching device is provided to switch a connection between the first connection pipe and the high pressure side pipe or the low pressure side pipe,
The second flow path switching device is
a heat medium-to-heat medium heat exchanger configured to function as an auxiliary condenser when the heat source-side heat exchanger functions as a condenser, and a heat medium-to-heat medium heat exchanger configured to function as an auxiliary evaporator when the heat source-side heat exchanger functions as an evaporator. The second flow path switching device is
When the utilization side heat exchanger functions as a condenser, the first connection pipe and the high pressure side pipe are connected to each other,
When the utilization side heat exchanger functions as an evaporator, the first connection pipe and the low pressure side pipe are connected to each other,
When the heat source side heat exchanger functions as a condenser, the first connection pipe and the high pressure side pipe of the heat medium relay machine are connected to each other,
The refrigeration cycle apparatus according to claim 1 , wherein, when the heat source side heat exchanger functions as an evaporator, the first connection pipe of the heat medium relay machine is connected to the low pressure side pipe. The user unit includes:
The refrigeration cycle apparatus according to claim 1 , further comprising: a first unit in which the utilization side heat exchanger functions as an evaporator; and a second unit in which the utilization side heat exchanger functions as a condenser. The heat transfer medium converter comprises:
a heat medium circulation circuit connected between the intermediate heat exchanger and the external heat source so that the heat medium circulates between the intermediate heat exchanger and the external heat source;
The refrigeration cycle apparatus according to any one of claims 1 to 3, further comprising: a pump that circulates the heat medium. a control device that varies the heat exchange capacity of the heat source side heat exchanger and the intermediate heat exchanger,
The heat source machine is
a heat source-side temperature sensor for detecting a temperature of a heat source heat medium exchanging heat with the refrigerant in the heat source-side heat exchanger;
The heat transfer medium converter comprises:
an external heat source temperature sensor for detecting a temperature of the external heat source;
The control device includes:
5. The refrigeration cycle apparatus according to claim 4, further comprising: a temperature sensor for detecting a temperature difference between the heat source side heat exchanger and the heat medium heat exchanger; The control device includes:
When the heat source side heat exchanger functions as a condenser and the temperature t of the external heat source temperature sensor is compared with the temperature T of the heat source side temperature sensor, in the case of T<t,
The refrigeration cycle apparatus according to claim 5 , further comprising: a controller configured to control the second flow switching device so that the refrigerant is not supplied to the heat medium relay unit. The control device includes:
When the heat source side heat exchanger functions as a condenser and the temperature t of the external heat source temperature sensor is compared with the temperature T of the heat source side temperature sensor, in the case of t<T,
The refrigeration cycle apparatus according to claim 5 , further comprising: a second flow switching device that controls the second flow switching device so that the high-pressure side pipe and the first connection pipe of the heat medium relay machine are connected to each other. The control device includes:
When the heat source side heat exchanger functions as an evaporator, and the temperature t of the external heat source temperature sensor is compared with the temperature T of the heat source side temperature sensor, in the case of t<T,
The refrigeration cycle apparatus according to claim 5 , further comprising: a controller configured to control the second flow switching device so that the refrigerant is not supplied to the heat medium relay unit. The control device includes:
When the heat source side heat exchanger functions as an evaporator, and the temperature t of the external heat source temperature sensor is compared with the temperature T of the heat source side temperature sensor, in the case of T<t,
The refrigeration cycle apparatus according to claim 5 , further comprising: a second flow switching device that controls the second flow switching device so that the low-pressure side pipe and the first connection pipe of the heat medium relay machine are connected to each other. The heat transfer medium converter comprises:
a first heat transfer device and a second heat transfer device connected to the external heat source having different temperatures,
The refrigeration cycle apparatus according to any one of claims 1 to 9, further comprising a connection pipe that sends the refrigerant of the second connection pipe of the first heat medium relay machine to the first connection pipe of the second heat medium relay machine. The heat transfer medium converter comprises:
a first heat transfer device and a second heat transfer device connected to the external heat source having different temperatures,
The first heat medium converter is
a first external heat source temperature sensor for detecting a temperature of the external heat source;
The second heat medium converter is
The refrigeration cycle apparatus according to claim 5 , further comprising a second external heat source temperature sensor that detects a temperature of the external heat source. The control device includes:
When the heat source side heat exchanger functions as a condenser, and when a temperature t1 of the first external heat source temperature sensor, a temperature t2 of the second external heat source temperature sensor, and a temperature T of the heat source side temperature sensor are compared, in a case where t1<T<t2,
12. The refrigeration cycle apparatus according to claim 11, wherein the second flow path switching device is controlled so as not to supply the refrigerant to the second heat medium relay unit and so as to connect the high-pressure side pipe and the first connection pipe of the first heat medium relay unit. The control device includes:
When the heat source side heat exchanger functions as an evaporator, and when a temperature t1 of the first external heat source temperature sensor, a temperature t2 of the second external heat source temperature sensor, and a temperature T of the heat source side temperature sensor are compared, in a case where t1<T<t2,
12. The refrigeration cycle apparatus according to claim 11, wherein the second flow path switching device is controlled so as not to supply the refrigerant to the first heat medium relay unit and so as to connect the low-pressure side pipe and the first connection pipe of the second heat medium relay unit. The control device includes:
When the heat source side heat exchanger functions as a condenser, and when a temperature t1 of the first external heat source temperature sensor, a temperature t2 of the second external heat source temperature sensor, and a temperature T of the heat source side temperature sensor are compared, in a case where t1<t2<T,
controlling the second flow path switching device so that the high pressure side pipe is connected to the first connection pipe of the first relay unit and the first connection pipe of the second relay unit;
The refrigeration cycle apparatus according to claim 11, wherein a flow rate of the pump of the first heat medium relay unit is controlled to be greater than a flow rate of the pump of the second heat medium relay unit. The control device includes:
When the heat source side heat exchanger functions as an evaporator, and when a temperature t1 of the first external heat source temperature sensor, a temperature t2 of the second external heat source temperature sensor, and a temperature T of the heat source side temperature sensor are compared, in a case where T<t1<t2,
controlling the second flow path switching device so that the low-pressure side piping is connected to the first connection piping of the first relay unit and the first connection piping of the second relay unit;
The refrigeration cycle apparatus according to claim 11, wherein a flow rate of the pump of the first heat medium relay unit is controlled to be greater than a flow rate of the pump of the second heat medium relay unit. The second branch portion is
The refrigeration cycle device according to any one of claims 1 to 15, wherein the refrigerant is configured to be able to flow through the high-pressure side piping and the low-pressure side piping via a flow control device and an internal heat exchanger.

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