Refrigeration cycle device

Abstract

A refrigeration cycle device according to one embodiment of the present invention comprises a primary refrigerant circuit, a secondary refrigerant circuit, and a control device. The primary refrigerant circuit includes a heat source device and a refrigerant-to-refrigerant heat exchanger. The secondary refrigerant circuit is connected to the refrigerant-to-refrigerant heat exchanger and has a heating device, a hot water storage tank, a circulation amount adjustment means, and a flow path switching means. The flow path switching means switches between a heating operation for causing a secondary refrigerant that has flowed out from the refrigerant-to-refrigerant heat exchanger to flow into the heating device and a hot water supply operation for causing the secondary refrigerant that has flowed out from the refrigerant-to-refrigerant heat exchanger to flow into the hot water storage tank. When the secondary refrigerant circuit switches between the heating operation and the hot water supply operation, the control device executes circulation amount decrease control for controlling the circulation amount adjustment means such that the circulation amount of the secondary refrigerant after the switching decreases by a prescribed amount lower than the circulation amount of the secondary refrigerant before the switching.

Description

Refrigeration cycle apparatus

[0001] The present invention relates to a refrigeration cycle apparatus comprising a primary refrigerant circuit and a secondary refrigerant circuit.

[0002] Conventionally, refrigeration cycle apparatuses that perform hot water supply and heating using a heat pump as a heat source have been proposed (see, for example, Patent Document 1). In this type of refrigeration cycle apparatus, when only hot water supply is requested by a user, the flow path direction of the heat medium is switched to the hot water storage tank side to supply hot water; when only heating is requested by the user, the flow path direction of the heat medium is switched to the heating equipment side to perform heating; when both hot water supply and heating are requested by the user, the flow path direction of the heat medium is alternately switched between the hot water storage tank side and the heating equipment side, so that hot water supply and heating are performed respectively.

[0003] Japanese Patent No. 5854862

[0004] However, in the above-described technology, when switching between hot water supply and heating, since the required temperature of the heat medium differs for each operation, the following problems may temporarily occur. For example, low-temperature heat medium flows into the heating equipment, and the heat medium absorbs heat from indoor air, resulting in a decrease in room temperature (a decrease in comfort). In addition, when high-temperature heat medium flows into heating equipment such as floor heating, a person touching the floor feels heat (a decrease in comfort). Furthermore, low-temperature heat medium flows into the hot water storage tank, and the heat medium absorbs heat from the hot water stored in the hot water storage tank, causing the hot water temperature to decrease, which prolongs the operation time until the hot water temperature reaches the set temperature (an increase in power consumption).

[0005] In view of the above circumstances, an object of the present invention is to provide a refrigeration cycle apparatus capable of performing hot water supply and heating while suppressing a decrease in comfort and energy saving performance.

[0006] A refrigeration cycle device according to one embodiment of the present invention comprises a primary refrigerant circuit through which a primary refrigerant circulates, a secondary refrigerant circuit through which a secondary refrigerant circulates, and a control device. The primary refrigerant circuit includes a heat source device and a refrigerant-to-refrigerant heat exchanger. The secondary refrigerant circuit is connected to the refrigerant-to-refrigerant heat exchanger and includes a heating device, a hot water storage tank, a circulation rate adjustment means, and a flow path switching means. The circulation rate adjustment means adjusts the circulation rate of the secondary refrigerant. The flow path switching means switches between a heating operation, in which the secondary refrigerant flowing out of the refrigerant-to-refrigerant heat exchanger flows into the heating device, and a hot water supply operation, in which the secondary refrigerant flowing out of the refrigerant-to-refrigerant heat exchanger flows into the hot water storage tank. The control device controls the circulation rate adjustment means and the flow path switching means. When the control device switches the secondary refrigerant circuit between the heating operation and the hot water supply operation using the flow path switching means, it performs circulation rate reduction control, which controls the circulation rate adjustment means so that the circulation rate of the secondary refrigerant after the switch is reduced by a predetermined amount compared to the circulation rate of the secondary refrigerant before the switch.

[0007] The above-mentioned refrigeration cycle device performs the above-mentioned circulation rate reduction control when switching the secondary refrigerant circuit between heating operation and hot water supply operation, thereby suppressing the reduction in comfort and energy efficiency caused by the temperature difference of the heat transfer medium required for heating operation and hot water supply operation, while providing hot water and heating.

[0008] The secondary refrigerant circuit may further include a supply path for the secondary refrigerant flowing out of the refrigerant heat exchanger toward the heating device, a return path for the secondary refrigerant flowing out of the heating device toward the refrigerant heat exchanger, a hot water supply path that branches off from the supply path and merges with the return path via the hot water storage tank, and a supply temperature sensor that detects the supply temperature, which is the temperature of the secondary refrigerant flowing out of the refrigerant heat exchanger. The control device may include a target temperature acquisition unit that acquires a heating target temperature, which is the temperature of the secondary refrigerant required in the heating operation, and a hot water target temperature, which is the temperature of the secondary refrigerant required in the hot water supply operation. When the secondary refrigerant circuit is switched to the heating operation, the control device sets a predetermined amount to be larger the greater the difference between the heating target temperature and the supply temperature, and when the secondary refrigerant circuit is switched to the hot water supply operation, the control device sets a predetermined amount to be larger the greater the difference between the hot water target temperature and the supply temperature, which is the difference between the hot water target temperature and the supply temperature.

[0009] The circulation volume adjustment means may be a circulation pump. The control device may increase the rate at which the rotation speed of the circulation pump decreases as the target heating temperature difference or the target hot water temperature difference increases.

[0010] The control device may terminate the circulation rate reduction control when the supply temperature drops below a predetermined threshold when the secondary refrigerant circuit is switched from hot water supply operation to heating operation.

[0011] The control device may terminate the circulation rate reduction control when the secondary refrigerant circuit is switched from hot water supply operation to heating operation and the target heating temperature difference decreases to a predetermined specified value or less.

[0012] The hot water storage tank may have a heating temperature sensor for detecting the temperature of the heat exchange target of the secondary refrigerant. The control device may terminate the circulation rate reduction control when the supply temperature rises to or above the value detected by the heating temperature sensor when the secondary refrigerant circuit is switched from heating operation to hot water supply operation.

[0013] The control device may terminate the circulation volume reduction control earlier when it switches the secondary refrigerant circuit from the heating operation to the hot water supply operation than when it switches the secondary refrigerant circuit from the hot water supply operation to the heating operation.

[0014] The heat source device may be a heat pump having a compressor and an outdoor heat exchanger.

[0015] The control device may, when the secondary refrigerant circuit is switched from hot water supply operation to heating operation, control the rotation speed of the compressor so that the secondary refrigerant reaches the target heating temperature while the circulation volume reduction control is being performed, and when the secondary refrigerant circuit is switched from heating operation to hot water supply operation, control the rotation speed of the compressor so that the secondary refrigerant reaches the target hot water temperature while the circulation volume reduction control is being performed.

[0016] The flow path switching means may be a three-way valve provided at the branching point between the supply path and the hot water supply path, or at the junction between the hot water supply path and the return path.

[0017] The heating device may be an underfloor heating device.

[0018] According to the present invention, hot water supply and heating can be performed while suppressing a decrease in comfort and energy efficiency.

[0019] This is a refrigerant-water circuit diagram of a refrigeration cycle device according to one embodiment of the present invention. This is a block diagram showing the configuration of the control device in the above refrigeration cycle device. This is a schematic diagram showing an example of the time change of the secondary refrigerant temperature (supply temperature) and the actual tank temperature when switching from hot water supply operation to heating operation. This is a flowchart showing an example of a processing procedure executed by the control device when the above refrigeration cycle device is in a heating cycle (heating operation or hot water supply operation).

[0020] Embodiments of the present invention will be described below with reference to the drawings.

[0021] Figure 1 is a refrigerant-water circuit diagram of a refrigeration cycle device 100 according to one embodiment of the present invention. The refrigeration cycle device 100 of this embodiment comprises a refrigerant circuit 20 which is a primary refrigerant circuit and a water circuit 30 which is a secondary refrigerant circuit.

[0022] [Primary refrigerant circuit] The refrigerant circuit 20 comprises the outdoor unit 2 and the relay unit 50, and corresponds to the heat source device (heat pump) 55 in the refrigeration cycle device 100.

[0023] (Outdoor unit) The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an expansion valve 24, and an accumulator 25. These devices and the relay unit 50 are interconnected by piping to form the refrigerant circuit 20 (primary refrigerant circuit) in the refrigerant-water circuit of the refrigeration cycle device 100.

[0024] The compressor 21 is a variable-capacity compressor whose operating capacity can be varied by controlling its rotational speed with an inverter (not shown). The refrigerant discharge side of the compressor 21 is connected to port a of the four-way valve 22 by a discharge pipe 61. The refrigerant suction side of the compressor 21 is connected to the refrigerant outlet side of the accumulator 25 by a suction pipe 65.

[0025] The four-way valve 22 is a valve for switching the direction of refrigerant flow and has four ports a, b, c, and d. Port a is connected to the refrigerant discharge side of the compressor 21 by a discharge pipe 61, as described above. Port b is connected to one of the refrigerant inlets and outlets of the outdoor heat exchanger 23 by a refrigerant pipe 62. Port c is connected to the refrigerant inlet side of the accumulator 25 by a refrigerant pipe 66. Port d is connected to the gas refrigerant inlet and outlet 51b of the water refrigerant heat exchanger 51 in the relay unit 50, which will be described later, by an outdoor unit gas pipe 64.

[0026] The outdoor heat exchanger 23 exchanges heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29, which will be described later. One of the refrigerant inlets and outlets of the outdoor heat exchanger 23 is connected to port b of the four-way valve 22 by refrigerant piping 62, as described above, and the other refrigerant inlet and outlet is connected to the liquid refrigerant inlet and outlet 51a of the water refrigerant heat exchanger 51 (inter-refrigerant heat exchanger) in the relay unit 50, which will be described later, by the outdoor unit liquid pipe 63.

[0027] The expansion valve 24 is, for example, an electronic expansion valve. The expansion valve 24 is located in the outdoor unit liquid pipe 63 and its opening can be adjusted to reduce the pressure of the refrigerant passing through it.

[0028] The outdoor fan 29 is made of resin and is located near the outdoor heat exchanger 23. The outdoor fan 29 is driven by a fan motor (not shown) and takes in outside air from an intake port (not shown) of the outdoor unit 2, and releases the outside air, which has exchanged heat with the refrigerant in the outdoor heat exchanger 23, to the outside of the outdoor unit 2 from an outlet (not shown) of the outdoor unit 2.

[0029] (Relay Unit) The relay unit 50 has a water refrigerant heat exchanger 51 and a circulation pump 52, and is connected to the outdoor unit 2. In this embodiment, as shown in Figure 1, the relay unit 50 is described as being installed outside the outdoor unit 2, but the relay unit 50 may also be installed inside the outdoor unit 2.

[0030] The water-refrigerant heat exchanger 51 is, for example, a double-tube heat exchanger or a plate-type heat exchanger, and has a refrigerant-side flow path 511, a water-side flow path 512, a liquid refrigerant inlet / outlet 51a, a gas refrigerant inlet / outlet 51b, a water inlet 51c, and a water outlet 51d.

[0031] One end of the refrigerant-side flow path 511 is connected to the liquid refrigerant inlet / outlet 51a, and the other end is connected to the gaseous refrigerant inlet / outlet 51b. One end of the water-side flow path 512 is connected to the water inlet 51c, and the other end is connected to the water outlet 51d. In the water-refrigerant heat exchanger 51, heat exchange occurs between the refrigerant flowing through the refrigerant-side flow path 511 and the water flowing through the water-side flow path 512.

[0032] The liquid refrigerant inlet / outlet 51a is connected to the other refrigerant inlet / outlet of the outdoor heat exchanger 23 by the outdoor unit liquid pipe 63. The gas refrigerant inlet / outlet 51b is connected to port d of the four-way valve 22 by the outdoor unit gas pipe 64. The water inlet 51c is connected to the indoor unit 3 of the water circuit 30 by the second water pipe 12 and the indoor unit side second water branch pipe 121, and is also connected to the hot water supply device 4 of the water circuit 30 by the second water pipe 12 and the hot water supply device side second water branch pipe 122. The water outlet 51d is connected to port e of the three-way valve 35 by the first water pipe 11.

[0033] The circulation pump 52 is a variable-capacity pump driven by a motor (not shown). When the circulation pump 52 is driven, the water in the water circuit 30 circulates. The circulation pump 52 corresponds to a circulation volume adjustment means that adjusts the amount of secondary refrigerant (water) circulated.

[0034] The circulation pump 52 is not limited to a variable-capacity pump; a pump with a fixed rotational speed may also be used. In this case, the amount of secondary refrigerant (water) circulated can be adjusted by incorporating a flow control valve that can variably adjust the flow rate into the water circuit 30.

[0035] The relay unit 50 further includes a receiving unit 53 that receives input instructions from the user. The receiving unit 53 may be an input operation unit that receives input instructions from the user, or it may be a receiving device that receives an input signal corresponding to the input instructions generated by the input operation unit. The input instructions include, for example, instruction values ​​related to the set temperature of the indoor space in which the indoor unit 3 is installed, the set temperature of the hot water outlet of the hot water supply device 4, or the temperature of the water circulating in the water circuit 30 (the temperature of the water flowing out from the water refrigerant heat exchanger 51). When the receiving unit 53 of the relay unit 50 receives the input instructions, it transmits a message to that effect to the control device 90, which will be described later.

[0036] The flow rate of water circulated by the drive of the circulation pump 52 is controlled by the rotation speed of the motor. In the example shown in Figure 1, the circulation pump 52 is located in the second water pipe 12, but it may be located in the first water pipe 11 instead, or inside the relay unit 50.

[0037] The water circuit 30 may be equipped with an auxiliary heat source, such as a heater, as a heating means for heating the secondary refrigerant (water) circulating in the water circuit 30. The auxiliary heat source may be installed, for example, in the first water pipe 11. The auxiliary heat source may be located inside the relay unit 50.

[0038] [Secondary refrigerant circuit] The water circuit 30 comprises a relay unit 50, an indoor unit 3, a hot water supply device 4, and a three-way valve 35.

[0039] (Indoor Unit) The indoor unit 3 is an indoor unit that operates as a heating or cooling device. The indoor unit 3 has an indoor heat exchanger 31, an indoor fan 32, and an on / off valve 33. The indoor unit 3, together with the hot water supply device 4, is connected to the relay unit 50 to form the water circuit 30 (secondary refrigerant circuit) in the refrigerant-water circuit of the refrigeration cycle device 100. The number of indoor units 3 is not limited to one, and there may be two or more.

[0040] The indoor heat exchanger 31 is a water-air heat exchanger that performs heat exchange between water circulating in the water circuit 30 and indoor air taken into the interior of the indoor unit 3 by the rotation of the indoor fan 32. The inlet side of the indoor heat exchanger 31 is connected to the port f of the three-way valve 35 via the first indoor unit-side water branch pipe 111. The outlet side of the indoor heat exchanger 31 is connected to the water inlet 51c of the water-refrigerant heat exchanger 51 via the second water pipe 12 and the second indoor unit-side water branch pipe 121.

[0041] The indoor fan 32 is made of resin and disposed in the vicinity of the indoor heat exchanger 31. The indoor fan 32 is driven by an unillustrated fan motor, takes in indoor air from an unillustrated suction port of the indoor unit 3, and blows air that has undergone heat exchange with water in the indoor heat exchanger 31 into the room from an unillustrated blowout port of the indoor unit 3. The indoor fan 32 and the indoor heat exchanger 31 together constitute a fan coil unit (FCU).

[0042] Note that the indoor unit 3 may be another heating device such as a floor heating panel. In this case, the indoor unit 3 is configured as a heating device, and the cooling operation described later is not performed.

[0043] The on-off valve 33 is disposed on the first water pipe 11, and is a shut-off valve capable of shutting off the flow of water directed from the water outlet 51d of the water-refrigerant heat exchanger 51 to the indoor heat exchanger 31. The on-off valve 33 is switched to a closed state when the operation of the indoor unit 3 is stopped (or when the operation is to be stopped).

[0044] Note that instead of the on-off valve 33, a flow rate adjustment valve capable of arbitrarily adjusting the opening degree may be used. In this case, the flow rate of water flowing through the indoor heat exchanger 31 can be controlled in accordance with the opening degree of the flow rate adjustment valve. This improves the followability to the required capacity and enhances comfort. Furthermore, when there is only one indoor unit 3, the on-off valve 33 may be omitted.

[0045] (Water Heater) The water heater 4 includes a hot water storage tank 41 and a heat exchange section 42. The water heater 4, together with the indoor unit 3, is connected to the relay unit 50 to form the water circuit 30 (secondary refrigerant circuit) in the refrigerant-water circuit of the refrigeration cycle apparatus 100.

[0046] The heat exchanging part 42 is a heat exchanger that performs heat exchange between the water circulating in the water circuit 30 and the water in the hot water storage tank 41. The inlet side of the heat exchanging part 42 is connected to the port g of the three-way valve 35 through the first water branch pipe on the water heater side 112. The outlet side of the heat exchanging part 42 is connected to the water inlet 51c of the water-refrigerant heat exchanger 51 through the second water pipe 12 and the second water branch pipe on the water heater side 122. The second water branch pipe on the water heater side 122 is connected to the second water pipe 12 and the second water branch pipe on the indoor unit side 121 at the confluence point 36.

[0047] Although not shown in the figure, a city water pipe and a hot water outlet pipe are connected to the hot water storage tank 41. In addition, the hot water storage tank 41 may be equipped with a booster heater for rapid heating.

[0048] (Three-way valve) The three-way valve 35 is an example of a flow path switching means that switches the flow direction of water, and includes three ports e, f, and g. The port e is connected to the water outlet 51d of the water-refrigerant heat exchanger 51 through the first water pipe 11. The port f is connected to the inlet side of the indoor heat exchanger 31 through the first water branch pipe on the indoor unit side 111. The port g is connected to the inlet side of the heat exchanging part 42 of the water heater 4 through the first water branch pipe on the water heater side 112.

[0049] The three-way valve 35 has a first state where the port e communicates with the port f, and a second state where the port e communicates with the port g. When the refrigeration cycle apparatus 100 performs a cooling operation or a heating operation, the three-way valve 35 is switched to the first state. On the other hand, when the refrigeration cycle apparatus 100 performs a hot water supply operation, the three-way valve 35 is switched to the second state.

[0050] When the three-way valve 35 is in the first state, the first water pipe 11 and the first water branch pipe on the indoor unit side 111 correspond to an outgoing path through which water flowing out of the water-refrigerant heat exchanger 51 flows toward the indoor unit 3, and the second water pipe 12 and the second water branch pipe on the indoor unit side 121 correspond to a return path through which water flowing out of the indoor unit 3 flows toward the water-refrigerant heat exchanger 51.

[0051] On the other hand, when the three-way valve 35 is in the second state, the first water branch pipe on the water heater side 112 and the second water branch pipe on the water heater side 122 correspond to a hot water supply path that branches from the outgoing path, passes through the hot water storage tank 41, and joins the return path.

[0052] Furthermore, the three-way valve 35 corresponds to the branching point between the supply path and the hot water supply path, and the merging point 36 corresponds to the merging point between the hot water supply path and the return path. The three-way valve 35 is not limited to being provided at the branching point as in this embodiment, but may also be provided at the merging point.

[0053] [Sensors] Various sensors are provided in the refrigeration cycle device 100. In the outdoor unit 2, the discharge pipe 61 is provided with a high-pressure sensor 71 for detecting the pressure of the refrigerant discharged from the compressor 21 and a discharge temperature sensor 72 for detecting the temperature of the refrigerant discharged from the compressor 21. The suction pipe 65 is provided with a low-pressure sensor 73 for detecting the pressure of the refrigerant drawn into the compressor 21 and a suction temperature sensor 74 for detecting the temperature of the refrigerant drawn into the compressor 21.

[0054] The outdoor heat exchanger 23 is equipped with a heat exchanger temperature sensor 75 for detecting the temperature of the refrigerant flowing through the outdoor heat exchanger 23. Furthermore, an outside air temperature sensor 76 is provided near the intake port (not shown) of the outdoor unit 2 for detecting the temperature of the outside air flowing into the outdoor unit 2, i.e., the outside air temperature.

[0055] The indoor unit 3 may be equipped with a room temperature sensor 77 that detects the temperature of the air flowing into the indoor unit 3 (room temperature). The room temperature sensor 77 corresponds to a detection means for detecting the indoor load. The indoor load is calculated based on the difference between the temperature of the room in which the indoor unit 3 is installed (room temperature) and the set temperature of the indoor unit 3 (target room temperature).

[0056] The hot water supply system 4 is equipped with a hot water temperature sensor 80 that detects the temperature of the water or hot water (hereinafter also referred to as tank water) in the hot water storage tank 41 (hereinafter also referred to as actual tank temperature or hot water temperature). The hot water temperature sensor 80 corresponds to a heated temperature sensor that detects the temperature of the heat exchange target of the secondary refrigerant.

[0057] The water circuit 30 is equipped with a supply temperature sensor 78 and a return temperature sensor 79. The supply temperature sensor 78 is installed in the first water pipe 11 connected to the outlet 51d of the water refrigerant heat exchanger 51 and detects the temperature of the water supplied to the indoor unit 3 or the hot water supply device 4 (supply temperature). The return temperature sensor 79 is installed in the second water pipe 12 connected to the inlet 51c of the water refrigerant heat exchanger 51 and detects the temperature of the water flowing into the water refrigerant heat exchanger 51 (return temperature).

[0058] [Control device] The control device 90 is, for example, an outdoor control device provided in the outdoor unit 2, and is mounted on a control board housed in an electrical equipment box (not shown) of the outdoor unit 2.

[0059] Figure 2 is a block diagram showing the configuration of the control device 90. As shown in the figure, the control device 90 includes a CPU 91, a storage unit 92, a communication unit 93, a sensor input unit 94, and a rotation speed detection unit 95.

[0060] The memory unit 92 is a non-volatile memory such as flash memory, and stores the control program and control parameters of the outdoor unit 2, detected values ​​corresponding to detection signals from various sensors, the control status of the compressor 21 and outdoor fan 29, the rotation speed of the indoor fan 32 acquired via the communication unit 93, and the control status of the indoor unit 3 and the hot water supply device 4, including the operating mode entered by the user.

[0061] The communication unit 93 is an interface for communication with the indoor unit 3, the hot water supply unit 4, and the relay unit 50. The sensor input unit 94 takes in the detection results from various sensors of the outdoor unit 2 and outputs them to the CPU 91. The rotation speed detection unit 95 detects the rotation speed of the compressor 21 motor and outputs it to the CPU 91. The rotation speed detection unit 95 may be configured to directly detect the rotation speed of the motor using an encoder or the like attached to the motor's drive shaft, or it may be configured to detect the rotation speed of the motor from the drive current supplied to the motor. In the following description, the rotation speed of the compressor 21 refers to the rotation speed of the motor.

[0062] The CPU 91 is a control unit that controls the operation of each part of the outdoor unit 2, including the compressor 21, by executing a program stored in the memory unit 92. The program is installed in the control unit 90, for example, via various storage media. Alternatively, the program may be installed via the internet or the like.

[0063] The CPU 91 receives the detection results from each sensor of the outdoor unit 2 described above via the sensor input unit 94. Furthermore, the CPU 91 receives control signals transmitted from the indoor unit 3, the hot water heater 4, and the relay unit 50 (receiving unit 53) via the communication unit 93. The control signals transmitted from the indoor unit 3 include the required operating capacity (room temperature setting) requested by the indoor unit 3. The control signals transmitted from the hot water heater 4 include the required operating capacity (hot water outlet temperature setting) requested by the hot water heater. The control signals transmitted from the relay unit 50 (receiving unit 53) include instruction values ​​related to the temperature of the water circulating in the water circuit 30 (temperature of the water flowing out from the water refrigerant heat exchanger 51) and user input instructions. The control signals transmitted from the relay unit 50 may also include control signals transmitted from the indoor unit 3 or the hot water heater 4 described above.

[0064] The CPU 91 sets a heating target temperature, which is the temperature of the secondary refrigerant (water) (supply temperature) necessary to achieve the room temperature set to that temperature, and sets a hot water target temperature, which is the temperature of the secondary refrigerant (water) (supply temperature) necessary to achieve the hot water temperature set to that temperature. In this case, the communication unit 93 and the CPU 91 correspond to a "target temperature acquisition unit" that acquires the above heating target temperature and the above hot water target temperature.

[0065] Based on the received detection results and control signals, the CPU 91 controls the drive of the compressor 21, outdoor fan 29, indoor fan 32, and circulation pump 52, for example, by setting the indicated rotational speed at which these devices are driven. The CPU 91 also controls the switching of the four-way valve 22 and three-way valve 35 based on the received detection results and control signals. Furthermore, the CPU 91 controls the opening degree of the expansion valve 24 and the opening and closing of the on-off valve 33, etc., based on the received detection results and control signals.

[0066] [Basic Operation of the Refrigeration Cycle System] Next, the basic operation of the refrigeration cycle system 100 will be explained. The operation of the refrigeration cycle system 100 during cooling operation, heating operation, and hot water supply operation will be explained below.

[0067] (Cooling Operation) When the refrigeration cycle unit 100 performs cooling operation, the four-way valve 22 is switched to the state shown by the solid line in Figure 1, that is, port a and port b are in communication and port c and port d are in communication, and the three-way valve 35 is switched to the first state in which port e and port f are in communication, and the compressor 21 and circulation pump 52 are driven. When the compressor 21 is driven, refrigerant circulates in the refrigerant circuit 20, and when the circulation pump 52 is driven, water circulates in the water circuit 30. As a result, the outdoor heat exchanger 23 functions as a condenser, the water-refrigerant heat exchanger 51 functions as an evaporator, and the indoor unit 3 operates as a cooling device.

[0068] The rotational speed of the compressor 21 and the flow rate of the circulation pump 52 are determined according to information regarding the indoor load or information regarding the heat load of the water circuit 30. Here, "indoor load" refers to the load calculated based on the detection results of various sensors in the indoor unit 3. Also, "heat load" refers to the load calculated based on the detection results of various sensors in the water circuit 30.

[0069] The refrigerant, compressed by the compressor 21 to a high temperature and high pressure, is discharged from the compressor 21, flows through the discharge pipe 61, enters the four-way valve 22, flows from the four-way valve 22 into the refrigerant piping 62, and enters the outdoor heat exchanger 23. The refrigerant that enters the outdoor heat exchanger 23 condenses by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29.

[0070] The refrigerant flowing out from the outdoor heat exchanger 23 flows through the outdoor unit liquid pipe 63 and is depressurized as it passes through the expansion valve 24. Here, the opening of the expansion valve 24 is set so that the superheat (degree of superheating) of the refrigerant drawn into the compressor 21 reaches the target superheat, which is necessary to achieve the set temperature during cooling operation in the room where the indoor unit 3 is installed.

[0071] The refrigerant that passes through the expansion valve 24 and flows through the outdoor unit liquid pipe 63 flows into the liquid refrigerant inlet / outlet 51a of the water refrigerant heat exchanger 51. The refrigerant that flows into the liquid refrigerant inlet / outlet 51a passes through the refrigerant-side flow path 511 and exchanges heat with the water flowing through the water-side flow path 512, evaporating and flowing into the outdoor unit gas pipe 64 from the gas refrigerant inlet / outlet 51b of the water refrigerant heat exchanger 51. The refrigerant that flows into the outdoor unit gas pipe 64 flows through the four-way valve 22, refrigerant piping 66, accumulator 25 and suction pipe 65, and is drawn into the compressor 21 and compressed again.

[0072] Meanwhile, the water cooled as it flows through the water-side channel 512 flows into the first water pipe 11 from the outlet 51d of the water refrigerant heat exchanger 51. The water that flows out of the first water pipe 11 flows into the three-way valve 35, and from the three-way valve 35 flows into the indoor heat exchanger 31 of the indoor unit 3 via the indoor unit side first water branch pipe 111 and the open-off valve 33. The refrigerant that flows into the indoor heat exchanger 31 cools the indoor air passing through the indoor heat exchanger 31 by the rotation of the indoor fan 32, thereby cooling the room in which the indoor unit 3 is installed.

[0073] Water flowing out of the indoor heat exchanger 31 flows into the second water pipe 12 via the indoor unit side second water branch pipe 121 and is drawn into the circulation pump 52. The water drawn into the circulation pump 52 is sent to the inlet 51c of the water refrigerant heat exchanger 51, passes through the water side flow path 512, and is cooled again by the refrigerant flowing through the refrigerant side flow path 511.

[0074] (Heating Operation) When the refrigeration cycle unit 100 performs heating operation, the four-way valve 22 is switched to the state shown by the dashed line in Figure 1, that is, port a and port d are in communication and port b and port c are in communication, and the three-way valve 35 is switched to the first state in which port e and port f are in communication, and the compressor 21 and circulation pump 52 are driven. When the compressor 21 is driven, refrigerant circulates in the refrigerant circuit 20, and when the circulation pump 52 is driven, water circulates in the water circuit 30. As a result, the outdoor heat exchanger 23 functions as an evaporator, the water-refrigerant heat exchanger 51 functions as a condenser, and the indoor unit 3 operates as a heating device.

[0075] The rotational speed of the compressor 21 and the flow rate of the circulation pump 52 are determined according to information regarding the indoor load or information regarding the heat load of the water circuit 30.

[0076] The refrigerant, compressed by the compressor 21 to a high temperature and high pressure, is discharged from the compressor 21, flows through the discharge pipe 61, enters the four-way valve 22, flows from the four-way valve 22 to the outdoor unit gas pipe 64, and enters the gas refrigerant inlet / outlet 51b of the water refrigerant heat exchanger 51. The refrigerant that enters the gas refrigerant inlet / outlet 51b passes through the refrigerant-side flow path 511 and heats the water flowing through the water-side flow path 512. The refrigerant that has condensed through heat exchange with the water flowing through the water-side flow path 512 flows out from the liquid-side inlet / outlet 51a of the water refrigerant heat exchanger 51 into the outdoor unit liquid pipe 63.

[0077] The refrigerant that flows out into the outdoor unit liquid pipe 63 is depressurized as it passes through the expansion valve 24. Here, the opening of the expansion valve 24 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out of the water-refrigerant heat exchanger 51 becomes the target subcooling, which is necessary to achieve the set temperature during heating operation in the room where the indoor unit 3 is installed.

[0078] The refrigerant that passes through the expansion valve 24 and flows through the outdoor unit liquid pipe 63 flows into the outdoor heat exchanger 23. The refrigerant that flows into the outdoor heat exchanger 23 exchanges heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29 and evaporates. The refrigerant that flows out of the outdoor heat exchanger 23 flows through the refrigerant piping 62 and is drawn into the compressor 21 via the four-way valve 22, refrigerant piping 66, accumulator 25 and suction pipe 65, where it is compressed again.

[0079] Meanwhile, the water heated as it flows through the water-side channel 512 flows into the first water pipe 11 from the outlet 51d of the water-refrigerant heat exchanger 51. The refrigerant that flows out of the first water pipe 11 flows into the three-way valve 35 and flows into the indoor heat exchanger 31 via the indoor unit side first water branch pipe 111 and the open-off valve 33. The refrigerant that flows into the indoor heat exchanger 31 heats the indoor air passing through the indoor heat exchanger 31 by the rotation of the indoor fan 32, thereby heating the room in which the indoor unit 3 is installed.

[0080] Water flowing out of the indoor heat exchanger 31 flows into the second water pipe 12 via the indoor unit side second water branch pipe 121 and is drawn into the circulation pump 52. The water drawn into the circulation pump 52 is sent to the inlet 51c of the water-refrigerant heat exchanger 51, passes through the water-side flow path 512, and is heated again by the refrigerant flowing through the refrigerant-side flow path 511.

[0081] (Hot water supply operation) When the refrigeration cycle unit 100 performs hot water supply operation, the four-way valve 22 is switched to the state shown by the dashed line in Figure 1, that is, port a and port d are in communication and port b and port c are in communication, and the three-way valve 35 is switched to the second state in which port e and port g are in communication, and the compressor 21 and circulation pump 52 are driven. When the compressor 21 is driven, refrigerant circulates in the refrigerant circuit 20, and when the circulation pump 52 is driven, water circulates in the water circuit 30. As a result, the outdoor heat exchanger 23 functions as an evaporator and the water-refrigerant heat exchanger 51 functions as a condenser.

[0082] The rotational speed of the compressor 21 and the flow rate of the circulation pump 52 are determined according to information regarding the hot water set temperature or information regarding the heat load of the water circuit 30.

[0083] The refrigerant, compressed by the compressor 21 to a high temperature and high pressure, is discharged from the compressor 21, flows through the discharge pipe 61, enters the four-way valve 22, flows from the four-way valve 22 to the outdoor unit gas pipe 64, and enters the gas refrigerant inlet / outlet 51b of the water refrigerant heat exchanger 51. The refrigerant that enters the gas refrigerant inlet / outlet 51b passes through the refrigerant-side flow path 511 and heats the water flowing through the water-side flow path 512. The refrigerant that has condensed through heat exchange with the water flowing through the water-side flow path 512 flows out from the liquid-side inlet / outlet 51a of the water refrigerant heat exchanger 51 into the outdoor unit liquid pipe 63.

[0084] The refrigerant that flows into the outdoor unit liquid pipe 63 is depressurized as it passes through the expansion valve 24. Here, the opening of the expansion valve 24 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out of the water-refrigerant heat exchanger 51, which is necessary to achieve the hot water set temperature in the hot water supply system 4, becomes the target subcooling.

[0085] The refrigerant that passes through the expansion valve 24 and flows through the outdoor unit liquid pipe 63 flows into the outdoor heat exchanger 23. The refrigerant that flows into the outdoor heat exchanger 23 exchanges heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29 and evaporates. The refrigerant that flows out of the outdoor heat exchanger 23 flows through the refrigerant piping 62 and is drawn into the compressor 21 via the four-way valve 22, refrigerant piping 66, accumulator 25 and suction pipe 65, where it is compressed again.

[0086] Meanwhile, the water heated as it flows through the water-side channel 512 flows into the first water pipe 11 from the outlet 51d of the water-refrigerant heat exchanger 51. The refrigerant that flows out of the first water pipe 11 flows into the three-way valve 35 and into the heat exchange section 42 via the first water branch pipe 112 on the hot water supply side. The refrigerant that flows into the heat exchange section 42 heats the water in the hot water storage tank 41 by exchanging heat with the water in the hot water storage tank 41.

[0087] The water that flows out from the heat exchange section 42 flows into the second water pipe 12 via the second water branch pipe 122 on the hot water supply side and is drawn into the circulation pump 52. The water drawn into the circulation pump 52 is sent to the water inlet 51c of the water-refrigerant heat exchanger 51, passes through the water-side flow path 512, and is heated again by the refrigerant flowing through the refrigerant-side flow path 511.

[0088] When switching between hot water supply and heating operations, the following temporary problems may occur because the required temperatures of the heat transfer medium differ for each operation.

[0089] For example, in a control system for hot water supply operation that heats the tank water with a heat transfer medium at a predetermined temperature (e.g., 5°C) higher than the actual tank temperature, if the actual tank temperature is low, the heat transfer medium temperature will also be low. Therefore, if the system switches from hot water supply operation to heating operation while the supply temperature of the heat transfer medium is lower than the room temperature during the heating of the tank water, the low-temperature heat transfer medium will flow into the heating system, and the heat transfer medium will absorb heat from the indoor air, lowering the room temperature and potentially reducing indoor comfort.

[0090] On the other hand, if the supply temperature is higher than the room temperature just before switching from hot water supply to heating, high-temperature heat transfer fluid may flow into heating equipment such as underfloor heating, causing people who touch the floor to feel the heat and reducing comfort.

[0091] Furthermore, if the supply temperature immediately before switching from heating to hot water operation is lower than the water temperature in the hot water storage tank, a low-temperature heat transfer medium will flow into the hot water storage tank. This medium will absorb heat from the hot water stored in the tank, lowering the water temperature. As a result, the operating time to reach the set hot water temperature will increase, leading to increased power consumption.

[0092] To resolve these issues, the control device 90 adjusts the amount of water circulated in the water circuit 30 when switching between hot water supply and heating operations, thereby suppressing a decrease in comfort and energy efficiency while providing hot water and heating. The details of the control device 90 will be described below.

[0093] [Details of the control device] In this embodiment, when the control device 90 switches the water circuit 30 between heating operation and hot water supply operation using the three-way valve 35, it performs circulation volume reduction control by controlling the circulation pump 52 so that the amount of secondary refrigerant (water) circulated after the switch is reduced by a predetermined amount compared to the amount of secondary refrigerant (water) circulated before the switch.

[0094] By reducing the circulation rate of the secondary refrigerant (water), which is the heat transfer medium, the amount of heat exchange between the secondary refrigerant (water) and the object being heated (indoor air in the case of heating operation, and tank water in the case of hot water supply operation) is reduced. As a result, the amount of heat absorbed or heated by the object being heated is suppressed, thereby preventing a decrease in comfort and energy efficiency.

[0095] The above predetermined amount is set according to the magnitude of the heating target temperature difference, which is the temperature difference between the heating target temperature and the supply temperature, in the case of heating operation, and according to the hot water target temperature difference, which is the temperature difference between the hot water target temperature and the supply temperature, in the case of hot water operation. Specifically, the larger the heating target temperature difference, the larger the above predetermined amount is set, and the larger the hot water target temperature difference, the larger the above predetermined amount is set. In this embodiment, the decrease in the amount of heat transfer fluid circulation is adjusted by increasing the rate or amount of decrease in the rotation speed of the circulation pump 52 as the heating target temperature difference or hot water target temperature difference increases.

[0096] The greater the difference between the target temperature (heating target temperature and hot water target temperature) and the actual temperature (supply temperature) of the secondary refrigerant (water), the greater the fluctuation in the temperature of the heated object relative to the target temperature when switching between heating and hot water operation. By adjusting the amount of reduction in the heat transfer fluid circulation rate according to this difference, the following effects can be obtained.

[0097] For example, if the difference between the target temperature and the actual temperature is small, and the reduction in the amount of heat transfer fluid circulated is too large, the primary refrigerant circuit may experience poor heat dissipation, potentially causing the compressor 21 to shut down under high pressure protection. However, by adjusting the amount of heat transfer fluid reduction according to the difference between the target temperature and the actual temperature, it is possible to prevent poor heat dissipation in the primary refrigerant circuit, allowing the compressor 21 to continue operating without stopping, and suppressing a decrease in comfort during heating operation.

[0098] On the other hand, when the difference between the target temperature and the actual temperature is large (the temperature fluctuation range of the object being heated relative to the target temperature is large), if the degree of reduction in the heat transfer fluid circulation rate is too small, the heat absorption and heating suppression effect on the object being heated may be insufficient. However, by adjusting the amount of reduction in the heat transfer fluid rate according to the difference between the target temperature and the actual temperature, it is possible to appropriately suppress heat absorption and heating on the object being heated, thereby ensuring comfort and energy savings.

[0099] The target heating temperature varies depending on the set temperature and load (outside temperature), but is set to, for example, 30°C to 50°C (for example, around 35°C in the case of underfloor heating). On the other hand, the target hot water temperature is set to a predetermined temperature (for example, 5°C) higher than the actual tank temperature (water temperature).

[0100] When the water circuit 30 is switched from hot water supply operation to heating operation, the control device 90 may control the rotation speed of the compressor 21 during the execution of the circulation volume reduction control so that the secondary refrigerant (water) reaches the heating target temperature. For example, when the supply temperature is higher than the heating target temperature, the rotation speed of the compressor 21 is reduced to decrease the amount of heat exchanged in the water refrigerant heat exchanger 51, and when the supply temperature is lower than the heating target temperature, the rotation speed of the compressor 21 is increased to increase the amount of heat exchanged in the water refrigerant heat exchanger 51. This shortens the operating time due to the circulation volume reduction control and reduces the time it takes to reach the set temperature of the room, thereby further suppressing the decrease in comfort and energy efficiency.

[0101] Similarly, when the water circuit 30 is switched from heating operation to hot water supply operation, the control device 90 may control the rotation speed of the compressor 21 during the execution of the circulation volume reduction control so that the secondary refrigerant (water) reaches the target hot water temperature. For example, when the supply temperature is lower than the target hot water temperature, the rotation speed of the compressor 21 is increased to increase the amount of heat exchanged in the water refrigerant heat exchanger 51. This shortens the operating time due to the circulation volume reduction control and further suppresses the decrease in energy efficiency.

[0102] The control device 90 may terminate the circulation rate reduction control when the supply temperature drops below a predetermined threshold when the water circuit 30 is switched from hot water supply operation to heating operation. The threshold can be arbitrarily set according to the set temperature of the room temperature, etc., and is not particularly limited as long as it is a temperature that can suppress heat absorption and heating of the object to be heated (air). By terminating the circulation rate reduction control based on the supply temperature in this way, it is possible to suppress the decrease in comfort and energy efficiency that may occur due to the unnecessarily long operating time of the circulation rate reduction control.

[0103] Alternatively, the control device 90 may terminate the circulation rate reduction control when the heating target temperature difference decreases to a predetermined value or less when the water circuit 30 is switched from hot water supply operation to heating operation. The same effect as described above can be obtained by this method as well. The above predetermined value is not particularly limited as long as it is a temperature that can suppress heat absorption and heating of the object to be heated (air), for example, 5°C or less.

[0104] On the other hand, when the water circuit 30 is switched from heating operation to hot water supply operation, the control device 90 may terminate the circulation rate reduction control when the supply temperature rises to or above the value detected by the water temperature sensor 80. If the supply temperature is above the water temperature, no heat is absorbed from the object being heated (tank water), and therefore the circulation rate reduction control is terminated.

[0105] Figure 3 is a schematic diagram showing an example of the time-dependent changes in the secondary refrigerant temperature (supply temperature) and actual tank temperature when switching from hot water supply operation to heating operation.

[0106] When the system switches from heating operation to hot water supply operation at time T1, the control device 90 starts circulation rate reduction control. At time T1, the supply temperature is lower than the actual tank temperature, but the reduction in circulation rate control suppresses the decrease in the actual tank temperature immediately after the operation switch. In addition, by increasing the rotation speed of the compressor 21 so that the supply temperature reaches the target hot water temperature, the supply temperature can be increased, which promotes an early rise in the actual tank temperature. At time T2, when the supply temperature is higher than the actual tank temperature, the control device 90 ends the circulation rate reduction control and returns to normal control.

[0107] Furthermore, the hot water storage tank 41 has a larger heat capacity compared to floor heating panels, etc., and is less prone to temperature changes in the heated object. Therefore, when switching to hot water supply operation, it is easier to tolerate a difference between the target temperature and the heat transfer medium temperature than when switching to heating operation. For this reason, when switching from heating operation (floor heating) to hot water supply operation, it is possible to switch to the hot water supply cycle early, and when switching from hot water supply operation to heating operation (floor heating), it is possible to switch to the heating operation cycle only after the heat transfer medium temperature has dropped sufficiently.

[0108] In this case, the control device 90 may terminate the circulation rate reduction control earlier when switching the water circuit 30 from heating operation to hot water supply operation than when switching the water circuit 30 from hot water supply operation to heating operation. Alternatively, the amount of reduction in the circulation rate of the secondary refrigerant, which is set based on the target temperature difference, may be set to be smaller when switching from heating operation to hot water supply operation than when switching from hot water supply operation to heating operation.

[0109] Figure 4 is a flowchart showing an example of a processing procedure executed by the control device 90 when the refrigeration cycle device 100 is in a heating cycle (heating operation or hot water supply operation).

[0110] The control device 90 starts the operation of the refrigeration cycle device 100 in the heating cycle, and after the time required for the state of the primary refrigerant circulating in the refrigerant circuit 20 and the secondary refrigerant (water) circulating in the water circuit 30 to stabilize has elapsed, it determines whether the state of the three-way valve 35 has switched between the first state (heating operation) and the second state (hot water supply operation) (ST101).

[0111] If the control device 90 determines that the state of the three-way valve 35 has not changed (No in ST101), it continues to operate the refrigeration cycle device 100 without performing circulation rate reduction control. On the other hand, if it determines that the state of the three-way valve 35 has changed (Yes in ST101), it determines whether the operating mode after the change is heating operation or not (ST102). If the operating mode after the change is heating operation (Yes in ST102), the control device 90 calculates the heating target temperature difference, which is the difference between the supply temperature and the heating target temperature (ST103), and performs circulation rate reduction control, which controls the circulation pump 52 so that the circulation rate of the secondary refrigerant (water) decreases by an amount determined according to the calculated heating target temperature difference (ST104).

[0112] The control device 90 determines whether a predetermined time has elapsed since the start of the circulation volume reduction control (ST105), and if it determines that the predetermined time has elapsed (Yes in ST105), it determines whether the supply temperature is below a threshold (ST106). The predetermined time is set to any time (for example, 10 seconds) during which a fluctuation in the supply temperature is observed as a result of controlling the rotational speed of the compressor 21 after the start of the circulation volume reduction control.

[0113] When the control device 90 determines that the supply temperature exceeds a threshold (No in ST106), it returns to ST105. When it determines that the supply temperature is below the threshold (Yes in ST106), it terminates the circulation rate reduction control, returns the circulation rate of the secondary refrigerant to the state before the circulation rate reduction control, and performs normal heating operation control (ST107).

[0114] On the other hand, when the operating mode after switching is hot water supply operation (No in ST102), the control device 90 calculates the hot water supply target temperature difference, which is the difference between the supply temperature and the hot water supply target temperature (ST108), and performs circulation rate reduction control, which controls the circulation pump 52 so that the circulation rate of the secondary refrigerant (water) becomes the circulation rate determined according to the calculated hot water supply target temperature difference (ST109).

[0115] The control device 90 determines whether a predetermined time has elapsed since the start of the circulation volume reduction control (ST110), and if it determines that the predetermined time has elapsed, it determines whether the supply temperature is equal to or greater than the actual tank temperature (water temperature) (ST111). The predetermined time is set to any time (for example, 10 seconds) in which a fluctuation in the supply temperature is observed as a result of controlling the rotational speed of the compressor 21 after the start of the circulation volume reduction control.

[0116] When the control device 90 determines that the supply temperature is equal to or higher than the water temperature (Yes in ST111), it terminates the circulation rate reduction control, returns the circulation rate of the secondary refrigerant to the state before the circulation rate reduction control, and performs normal hot water supply operation control (ST107).

[0117] The control device 90 repeatedly performs the above process at predetermined intervals until the operation of the refrigeration cycle device 100 is stopped by user operation or the like (ST112).

[0118] Although embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above and can be modified in various ways.

[0119] For example, in the above embodiment, the number of indoor units 3 connected to the relay unit 50 was set to one, but it is not limited to this, and there may be two or more.

[0120] Furthermore, although the above embodiments have described a refrigeration cycle system equipped with a secondary refrigerant circuit using water as the secondary refrigerant as an example, the secondary refrigerant may be a refrigerant other than water.

[0121] 2...Outdoor unit 3...Indoor unit (heating device) 4...Hot water supply device 20...Refrigerant circuit (primary refrigerant circuit) 21...Compressor 23...Outdoor heat exchanger 30...Water circuit (secondary refrigerant circuit) 35...Three-way valve (flow path switching means) 41...Hot water storage tank 51...Water-refrigerant heat exchanger (inter-refrigerant heat exchanger) 52...Circulation pump (circulation amount adjustment means) 76...Outdoor air temperature sensor 77...Room temperature sensor 78...Supply temperature sensor 79...Return temperature sensor 80...Water temperature sensor (heated temperature sensor) 90...Control device 100...Refrigeration cycle device

Claims

1. A refrigeration cycle device comprising: a heat source device and a refrigerant-to-refrigerant heat exchanger, comprising: a primary refrigerant circuit through which a primary refrigerant circulates; a secondary refrigerant circuit connected to the refrigerant-to-refrigerant heat exchanger, through which a secondary refrigerant circulates, comprising: a heating device; a hot water storage tank; a circulation rate adjustment means for adjusting the circulation rate of the secondary refrigerant; a flow path switching means for switching between a heating operation in which the secondary refrigerant discharged from the refrigerant-to-refrigerant heat exchanger flows into the heating device and a hot water supply operation in which the secondary refrigerant discharged from the refrigerant-to-refrigerant heat exchanger flows into the hot water storage tank; and a control device for controlling the circulation rate adjustment means and the flow path switching means, wherein the control device performs circulation rate reduction control, which controls the circulation rate adjustment means so that when the flow path switching means switches the secondary refrigerant circuit between the heating operation and the hot water supply operation, the circulation rate after the switch is lower than the circulation rate of the secondary refrigerant before the switch by a predetermined amount.

2. A refrigeration cycle device according to claim 1, wherein the secondary refrigerant circuit further comprises: a supply path for the secondary refrigerant flowing out of the interrefrigerant heat exchanger toward the heating device; a return path for the secondary refrigerant flowing out of the heating device toward the interrefrigerant heat exchanger; a hot water supply path branching off from the supply path and merging with the return path via the hot water storage tank; and a supply temperature sensor for detecting the supply temperature, which is the temperature of the secondary refrigerant flowing out of the interrefrigerant heat exchanger, wherein the control device comprises a target temperature acquisition unit for acquiring a heating target temperature, which is the temperature of the secondary refrigerant required in the heating operation, and a hot water supply target temperature, which is the temperature of the secondary refrigerant required in the hot water supply operation, wherein when the secondary refrigerant circuit is switched to the heating operation, the predetermined amount is set to be larger the greater the difference between the heating target temperature and the supply temperature, and when the secondary refrigerant circuit is switched to the hot water supply operation, the predetermined amount is set to be larger the greater the difference between the hot water supply target temperature and the supply temperature.

3. A refrigeration cycle device according to claim 2, wherein the circulation volume adjustment means is a circulation pump, and the control device increases the rate of decrease in the rotation speed of the circulation pump as the heating target temperature difference or the hot water target temperature difference increases.

4. A refrigeration cycle device according to claim 2, wherein the control device terminates the circulation rate reduction control when the supply temperature falls below a predetermined threshold when the secondary refrigerant circuit is switched from hot water supply operation to heating operation.

5. A refrigeration cycle device according to claim 2, wherein the control device terminates the circulation rate reduction control when the secondary refrigerant circuit is switched from the hot water supply operation to the heating operation and the target heating temperature difference decreases to or below a predetermined specified value.

6. A refrigeration cycle device according to claim 2, wherein the hot water storage tank has a heated temperature sensor for detecting the temperature of the heat exchange target of the secondary refrigerant, and the control device terminates the circulation rate reduction control when the supply temperature rises to or above the value detected by the heated temperature sensor when the secondary refrigerant circuit is switched from the heating operation to the hot water supply operation.

7. A refrigeration cycle device according to claim 2, wherein the control device terminates the circulation volume reduction control earlier when the secondary refrigerant circuit is switched from the heating operation to the hot water supply operation than when the secondary refrigerant circuit is switched from the hot water supply operation to the heating operation.

8. A refrigeration cycle apparatus according to claim 1, wherein the heat source apparatus is a heat pump having a compressor and an outdoor heat exchanger.

9. A refrigeration cycle device according to claim 8, wherein the control device further controls the compressor, and when the secondary refrigerant circuit is switched from the hot water supply operation to the heating operation, the rotational speed of the compressor is controlled during the execution of the circulation volume reduction control so that the secondary refrigerant reaches the target heating temperature, and when the secondary refrigerant circuit is switched from the heating operation to the hot water supply operation, the rotational speed of the compressor is controlled during the execution of the circulation volume reduction control so that the secondary refrigerant reaches the target hot water temperature.

10. A refrigeration cycle device according to claim 2, wherein the flow path switching means is a three-way valve provided at a branching point between the supply path and the hot water supply path, or at a merging point between the hot water supply path and the return path.

11. A refrigeration cycle device according to claim 1, wherein the heating device is a floor heating device.

Images