Heat pump device

Abstract

A heat pump device (100) has, as an operation mode, a simultaneous mode in which cooling and hot water supply are simultaneously implemented. In the simultaneous mode, a flow path switching device (120) does not allow a refrigerant to circulate through a first heat exchanger (3) and causes the refrigerant to circulate such that a second heat exchanger (9a) acts as an evaporator and a third heat exchanger (16) acts as a condenser. A control device (110) is configured so as to: select a hot water supply mode when there is a need to heat water in a hot water supply tank (304) and a hot water supply request has been made; select one operation mode from among a cooling mode and the simultaneous mode when there is a need to heat the water in the hot water supply tank (304) and a hot water supply request has not been made; and select the cooling mode when there is no need to heat the water in the hot water supply tank (304).

Description

heat pump equipment

[0001] The present disclosure relates to a heat pump device.

[0002] Conventionally, there exists an air conditioning and hot water combined system that is equipped with a refrigerant circuit formed by connecting a utilization device (indoor unit) and a hot water unit to a heat source device (outdoor unit) via piping, and that is capable of simultaneously performing air conditioning operation and hot water operation (for example, JP 63-108163 A (Patent Document 1)).

[0003] Japanese Unexamined Patent Publication No. 63-108163

[0004] However, the system disclosed in JP 63-108163 A (Patent Document 1) does not take into consideration switching control for each operating mode, and there is a risk that the operation mode may be switched at a time not intended by the user, resulting in a loss of indoor comfort and energy efficiency.

[0005] For example, if the indoor load (required cooling capacity) is high and simultaneous operation of cooling and hot water supply is performed, the cooling capacity will be insufficient and it will take time for the indoor temperature to drop to the target value. Also, if the cooling operation is prioritized when the hot water load is high, there is a risk of running out of hot water.

[0006] The prior art does not take into consideration switching control for each operation mode, and there is room for improvement.

[0007] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a heat pump apparatus with improved switching control and improved comfort.

[0008] The present disclosure relates to a heat pump device. The heat pump device has operating modes including a cooling mode, a hot water supply mode, and a simultaneous mode in which cooling and hot water supply are performed simultaneously. The heat pump device includes a compressor that compresses a refrigerant, a first heat exchanger that exchanges heat between the refrigerant and outdoor air, a second heat exchanger that exchanges heat between the refrigerant and indoor air, a third heat exchanger connected to a liquid circulation path through which a liquid medium for heating water in a hot water tank circulates and that exchanges heat between the liquid medium and the refrigerant, a flow path switching device that can change the flow path for the refrigerant to flow through the compressor, the first heat exchanger, the second heat exchanger, and the third heat exchanger, and a control device that controls the flow path switching device. In the hot water supply mode, the flow path switching device does not circulate the refrigerant through the second heat exchanger, and circulates the refrigerant so that the first heat exchanger functions as an evaporator and the third heat exchanger functions as a condenser. In the simultaneous mode, the flow path switching device does not circulate refrigerant through the first heat exchanger, and circulates refrigerant so that the second heat exchanger acts as an evaporator and the third heat exchanger acts as a condenser. The control device is configured to select the hot water supply mode when water in the hot water tank needs to be heated and there is a hot water supply request, to select either the cooling mode or the simultaneous mode when water in the hot water tank needs to be heated and there is no hot water supply request, and to select the cooling mode when there is no need to heat water in the hot water tank.

[0009] According to the heat pump device of the present disclosure, a control device is provided that performs switching control based on the usage status of the hot water tank, etc., for switching to each operating mode, so that various operating modes can be appropriately switched to without compromising indoor comfort.

[0010] 1 is a diagram showing the configuration of a heat pump device of embodiment 1. FIG. 2 is a diagram for explaining a hot water tank connected to the heat pump device. FIG. 3 is a diagram showing the setting state of a flow path switching device for operation modes. FIG. 4 is a diagram showing the flow of refrigerant in a cooling mode of the heat pump device of embodiment 1. FIG. 5 is a diagram showing the flow of refrigerant in a heating mode of the heat pump device of embodiment 1. FIG. 6 is a diagram showing the flow of refrigerant in a hot water supply mode of the heat pump device of embodiment 1. FIG. 7 is a diagram showing the flow of refrigerant in a simultaneous mode of the heat pump device of embodiment 1. FIG. 8 is a diagram showing the flow of refrigerant in a defrost mode of the heat pump device of embodiment 1. FIG. 9 is a flowchart showing switching control between the cooling mode and the simultaneous mode in the heat pump device of embodiment 1. FIG. 10 is a flowchart showing switching control during heating operation of the heat pump device of embodiment 1. FIG. 11 is a diagram showing the configuration of a heat pump device of embodiment 2.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Although several embodiments will be described below, it was originally intended that the configurations described in each embodiment be combined as appropriate. Note that the same or corresponding parts in the drawings will be designated by the same reference numerals, and their description will not be repeated.

[0012] Embodiment 1 Fig. 1 is a diagram showing the configuration of a heat pump device according to embodiment 1. Fig. 2 is a diagram for explaining a hot water tank connected to the heat pump device.

[0013] The heat pump device 100 shown in Fig. 1 includes a heat source device 301, utilization devices 302a and 302b, and a hot water supply unit 303. The hot water supply unit 303 is connected to a hot water supply tank 304 shown in Fig. 2 .

[0014] One end of the hot water supply unit 303 is connected to the heat source device 301 via a gas pipe 15 which is a refrigerant pipe, and the other end is connected to the heat source device 301 via a liquid pipe 18 which is a refrigerant pipe.

[0015] The utilization devices 302a and 302b are connected to the heat source device 301 by gas pipes 11a and 11b, which are refrigerant pipes, and liquid pipes 8a and 8b, which are refrigerant pipes, respectively. In addition, the hot water supply tank 304 and the hot water supply unit 303 are connected by upstream water pipe 20 and downstream water pipe 21, which are water pipes.

[0016] In the first embodiment, two utilization devices, one hot water supply unit, and one hot water tank are connected to one heat source device, but this is not limited to this, and more or fewer of each device may be provided. The refrigerant used in the heat pump device 100 may be, for example, an HFC (hydrofluorocarbon) refrigerant such as R410A, R407C, or R404A, an HCFC (hydrochlorofluorocarbon) refrigerant such as R22 or R134a, or a natural refrigerant such as hydrocarbon, helium, or carbon dioxide.

[0017] The heat pump device 100 also includes a control device 110. In Fig. 1, the control device 110 is disposed in the heat source device 301, but this is just an example. The location where the control device 110 is disposed is not limited.

[0018] The utilization devices 302a and 302b are connected to the heat source device 301. The utilization devices 302a and 302b are installed in locations where they can blow conditioned air into the area to be air-conditioned (for example, embedded in the ceiling indoors, hung from the ceiling, or hung on a wall). The utilization devices 302a and 302b are connected to the heat source device 301 via liquid pipes 8a and 8b and gas pipes 11a and 11b, and constitute part of the refrigerant circuit.

[0019] The utilization devices 302a, 302b each include an indoor refrigerant circuit that constitutes part of the refrigerant circuit. This indoor refrigerant circuit is composed of second heat exchangers 9a, 9b (indoor heat exchangers) that serve as utilization-side heat exchangers. The utilization devices 302a, 302b are also provided with indoor fans 10a, 10b, respectively, that exchange heat with the refrigerant passing through the second heat exchangers 9a, 9b and then supply the conditioned air to a target air-conditioning area, such as a room.

[0020] Each of the second heat exchangers 9a, 9b may be, for example, a cross-fin fin-and-tube heat exchanger composed of a heat transfer tube and multiple fins. Alternatively, each of the second heat exchangers 9a, 9b may be a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, or a double-pipe heat exchanger. When the operating modes of the utilization devices 302a, 302b are the cooling mode and the simultaneous cooling and hot water supply mode, the second heat exchangers 9a, 9b function as refrigerant evaporators to cool the air in the air-conditioned area, and when the operating modes are the heating mode, the second heat exchangers 9a, 9b function as refrigerant condensers (or radiators) to heat the air in the air-conditioned area.

[0021] The indoor fans 10a, 10b draw indoor air into the utilization devices 302a, 302b, exchange heat with the refrigerant in the second heat exchangers 9a, 9b, and then supply the air as conditioned air to the air-conditioned area. In other words, the utilization devices 302a, 302b are capable of exchanging heat between the indoor air taken in by the indoor fans 10a, 10b and the refrigerant flowing through the second heat exchangers 9a, 9b. The indoor fans 10a, 10b are each configured to be able to change the flow rate of the conditioned air supplied to the second heat exchangers 9a, 9b. Each of the indoor fans 10a, 10b includes a fan, such as a centrifugal fan or a multi-blade fan, and a motor, such as a DC fan motor, that drives the fan.

[0022] The utilization devices 302a, 302b are also provided with the following various sensors: (1) temperature sensors 206a, 206b provided on the liquid side of the second heat exchangers 9a, 9b, respectively, to detect the temperature of the liquid refrigerant; (2) temperature sensors 207a, 207b provided on the gas side of the second heat exchangers 9a, 9b, respectively, to detect the temperature of the gas refrigerant; and (3) temperature sensors 208a, 208b provided on the indoor air intake side of the utilization devices 302a, 302b, respectively, to detect the temperature of the indoor air flowing into the unit.

[0023] The operation of the indoor fans 10a and 10b is controlled by a control unit (not shown) that is disposed in the utilization devices 302a and 302b, respectively, and controls normal operation including the cooling mode and heating mode of the utilization devices 302a and 302b.

[0024] Hot water supply unit 303 is connected to heat source device 301. As shown in Fig. 2 , hot water supply unit 303 supplies hot water to hot water supply tank 304, which is installed, for example, outdoors, and heats the water in hot water supply tank 304 to boil water. One end of hot water supply unit 303 is connected to heat source device 301 via gas piping 15, and the other end is connected to heat source device 301 via liquid piping 18, and these units form part of the liquid medium circuit in heat pump device 100.

[0025] The hot water supply unit 303 includes a hot water supply side refrigerant circuit that constitutes part of the refrigerant circuit. This hot water supply side refrigerant circuit has a third heat exchanger 16 (plate water heat exchanger). The hot water supply unit 303 also includes a pump 17 that supplies hot water that has exchanged heat with the refrigerant in the third heat exchanger 16 to a hot water tank or the like.

[0026] In the hot water supply mode, third heat exchanger 16 functions as a refrigerant condenser (or radiator) and heats water supplied by pump 17. Pump 17 supplies water into hot water supply unit 303, exchanges heat with the water in third heat exchanger 16 to turn it into hot water, and then supplies the hot water into hot water supply tank 304 to exchange heat with the water in hot water supply tank 304. In other words, in hot water supply unit 303, heat exchange occurs between the water supplied by pump 17 and the refrigerant flowing through third heat exchanger 16, and also between the water supplied by pump 17 and the water in hot water supply tank 304. The flow rate of water supplied to third heat exchanger 16 can be changed.

[0027] The hot water supply unit 303 is also provided with a temperature sensor 209, which is provided on the liquid refrigerant side of the third heat exchanger 16 as shown in FIG. 1, for detecting the temperature of the liquid refrigerant.

[0028] The heat source device 301 is installed, for example, outdoors. The heat source device 301 is connected to utilization devices 302a and 302b via liquid pipes 8a and 8b and gas pipes 11a and 11b. The heat source device 301 is also connected to a hot water supply unit 303 via a gas pipe 15 and a liquid pipe 18. The heat source device 301 constitutes a part of the refrigerant circuit in the heat pump device 100.

[0029] The heat source device 301 includes an outdoor refrigerant circuit that constitutes part of the refrigerant circuit. This outdoor refrigerant circuit includes a compressor 1 that compresses the refrigerant, two four-way valves (a first four-way valve 2 and a second four-way valve 13), and an accumulator 14 that stores excess refrigerant. The two four-way valves (the first four-way valve 2 and the second four-way valve 13) switch the refrigerant flow direction depending on the outdoor operation mode.

[0030] The heat source device 301 further includes an outdoor fan 4 for supplying air to the first heat exchanger 3, and an on-off valve 5 for controlling the flow path of the refrigerant.

[0031] Compressor 1 draws in refrigerant and compresses it to a high-temperature, high-pressure state. The compressor 1 installed in embodiment 1 is capable of changing its operating capacity and is configured, for example, as a positive displacement compressor driven by a motor (not shown) controlled by an inverter. Although embodiment 1 illustrates an example in which there is only one compressor 1, this is not limiting, and two or more compressors 1 may be connected in parallel depending on the number of utilization devices 302a, 302b and hot water supply units 303 connected, etc.

[0032] The flow path switching device 120 switches the direction of the refrigerant flow depending on the operation mode of the heat pump device 100 .

[0033] The flow path switching device 120 includes a first four-way valve 2, a second four-way valve 13, a first expansion valve 7a, a second expansion valve 19, and an on-off valve 5. The first four-way valve 2 has a first port P1 to a fourth port P4. The second four-way valve 13 has a fifth port P5 to an eighth port P8. The first port P1 is coupled to the discharge side of the compressor 1. The second port P2 is connected to one end of the first heat exchanger 3. One end of the on-off valve 5 is connected to the other end of the first heat exchanger 3. The first expansion valve 7a is connected between the other end of the on-off valve 5 and one end of the second heat exchanger 9a. The second expansion valve 19 is connected between the other end of the on-off valve 5 and one end of the third heat exchanger 16. The third port P3 and the seventh port P7 are coupled to the suction side of the compressor 1. The fourth port P4 is connected to the fifth port P5. The sixth port P6 is connected to the other end of the second heat exchanger 9a. The eighth port P8 is connected to the other end of the third heat exchanger 16.

[0034] The first heat exchanger 3 has a gas side connected to the first four-way valve 2 and a liquid side connected to the on-off valve 5. The first heat exchanger 3 can be configured, for example, as a cross-fin fin-and-tube heat exchanger composed of heat transfer tubes and multiple fins. The first heat exchanger 3 may also be configured as a microchannel heat exchanger, a shell-and-tube heat exchanger, a heat pipe heat exchanger, or a double-pipe heat exchanger. In the cooling mode and defrosting mode, the first heat exchanger 3 functions as a refrigerant condenser, causing the refrigerant to release heat. In the heating mode, the first heat exchanger 3 functions as a refrigerant evaporator, causing the refrigerant to absorb heat.

[0035] The outdoor blower 4 draws outdoor air into the heat source device 301, exchanges heat with the outdoor air in the first heat exchanger 3, and then discharges the air to the outside. In other words, the heat source device 301 is capable of exchanging heat between the outdoor air taken in by the outdoor blower 4 and the refrigerant flowing through the first heat exchanger 3. The outdoor blower 4 is configured to be able to change the flow rate of air supplied to the first heat exchanger 3, and includes a fan such as a propeller fan and a motor, such as a DC fan motor, that drives the fan.

[0036] The accumulator 14 is provided on the intake side of the compressor 1, and stores liquid refrigerant to prevent it from returning to the compressor 1 when an abnormality occurs in the heat pump device 100 or when there is a transient response in the operating state due to a change in operating control.

[0037] The heat source device 301 is also provided with the following various sensors: (1) a pressure sensor 201 provided on the discharge side of the compressor 1 to detect the high-pressure side pressure; (2) a temperature sensor 202 provided on the discharge side of the compressor 1 to detect the discharge temperature; (3) a temperature sensor 203 provided on the gas side of the first heat exchanger 3 to detect the gas refrigerant temperature; (4) a temperature sensor 204 provided on the liquid side of the first heat exchanger 3 to detect the temperature of the liquid refrigerant; and (5) an outdoor air temperature sensor 205 provided on the outdoor air intake side of the heat source device 301 to detect the temperature of the outdoor air flowing into the unit.

[0038] The operations of the compressor 1, the first four-way valve 2, the outdoor blower 4, the on-off valve 5, and the second four-way valve 13 are controlled by a control device 110. The operations of the expansion valves 7a, 7b, and 19 are also controlled by the control device 110. Although the control device 110 is disposed in the heat source device 301 in Fig. 1 and other figures, it may be disposed in another location such as a remote controller or a utilization device, or may be disposed in several separate locations.

[0039] The various quantities detected by the various temperature sensors and pressure sensors are input to the control device 110. The control device 110 then controls the compressor 1, the first four-way valve 2, the outdoor blower 4, the on-off valve 5, the expansion valves 7a and 7b, the indoor blower 10, the second four-way valve 13, the pump 17, and the expansion valve 19 based on the various quantities input.

[0040] That is, the control device 110 performs overall control of the operation of the heat pump device 100. The control device 110 includes a CPU and a memory.

[0041] The CPU is a computing entity that executes various programs to control the actuators of the heat pump device 100. The CPU executes various processes by executing the programs, but some or all of these functions may be implemented using dedicated hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0042] The memory provides a storage area for storing program code or various variables when the CPU executes various programs. The memory may be one or more non-transitory computer-readable media. Examples of the memory include volatile memory such as dynamic random access memory (DRAM) and static random access memory (SRAM), and non-volatile memory such as read-only memory (ROM) and flash memory. The CPU controls each actuator of the heat pump device 100 by executing the programs stored in the memory.

[0043] Specifically, based on instructions regarding the operation mode or set temperature, etc., via a remote control and detection information from various sensors, the control device 110 controls the drive frequency of the compressor 1, the switching of the first four-way valve 2, the rotation speed (including ON / OFF) of the outdoor blower 4, the opening and closing of the on-off valve 5, the opening degree of the expansion valves 7a and 7b, the rotation speed (including ON / OFF) of the indoor blower 10, the switching of the second four-way valve 13, the rotation speed (including ON / OFF) of the pump 17, and the opening degree of the expansion valve 19.

[0044] Hot water supply tank 304 shown in Fig. 2 is installed outdoors, for example, and stores hot water boiled by hot water supply unit 303. One end of hot water supply tank 304 is connected to hot water supply unit 303 via upstream water piping 20, and the other end is connected to hot water supply unit 303 via downstream water piping 21. Hot water supply tank 304 constitutes part of liquid circulation path 130 in heat pump apparatus 100. That is, as shown in Fig. 2, upstream water piping 20, downstream water piping 21, and pump 17 constitute liquid circulation path 130 through which water to be heated by third heat exchanger 16 circulates. Hot water supply tank 304 is a fill-to-fill type, and when a user consumes hot water, hot water flows from the top of the tank, and city water is supplied from the bottom of the tank according to the amount of hot water consumed.

[0045] Water sent by pump 17 to hot water supply unit 303 is heated by the refrigerant in third heat exchanger 16 to become hot water, and flows into hot water supply tank 304 via upstream water piping 20. The hot water that flows into hot water supply tank 304 exchanges heat with the water in the tank to lower its temperature, and after leaving hot water supply tank 304, flows back into hot water supply unit 303 via downstream water piping 21, is sent again by pump 17, and becomes hot water again in third heat exchanger 16. Water is boiled in hot water supply tank 304 through this process. Note that while Figure 2 shows a specification for indirectly boiling water, it is also possible to have a specification in which hot water from hot water supply tank 304 flows into hot water supply unit 303, where it is heated, and then boils water directly.

[0046] The hot water supply tank 304 is also provided with the following various sensors: (1) a water temperature sensor 212 provided on the side of the upper part of the hot water supply tank 304 to detect the hot water temperature at the upper part of the tank; (2) a water temperature sensor 213 provided below the water temperature sensor 212 to detect the hot water temperature at a part of the tank below the installation position of the water temperature sensor 212; (3) a water temperature sensor 214 provided below the water temperature sensor 213 to detect the hot water temperature at a part of the tank below the installation position of the water temperature sensor 213; (4) a water temperature sensor 215 provided on the side of the lower part of the hot water supply tank 304 to detect the hot water temperature at the lower part of the tank; and (5) a water temperature sensor 216 to detect the temperature of water supplied from the lower part of the hot water supply tank 304.

[0047] Fig. 3 is a diagram showing the setting state of the flow path switching device for each operation mode. When ON (solid line) is displayed in Fig. 3, it indicates that the flow paths indicated by solid lines inside the corresponding four-way valve shown in Fig. 1 are connected, and the flow paths indicated by dashed lines are not connected. Also, when OFF (dashed line) is displayed in Fig. 3, it indicates that the flow paths indicated by dashed lines inside the corresponding four-way valve shown in Fig. 1 are connected, and the flow paths indicated by solid lines are not connected.

[0048] Furthermore, when the on-off valve 5 is displayed as ON in FIG. 3, it indicates an open state, and when it is displayed as OFF, it indicates a closed state.

[0049] Furthermore, when the expansion valves 7 and 19 are displayed as ON in FIG. 3, this indicates that the flow rate is being adjusted, and when they are displayed as OFF, this indicates that they are closed.

[0050] In the cooling mode, the first four-way valve 2 is set to ON (solid line), the second four-way valve is set to OFF (dashed line), the on-off valve 5 is set to ON (open), the expansion valve 7 is set to ON (flow rate adjustment), and the expansion valve 19 is set to OFF (closed).

[0051] By being set in this manner, in the cooling mode, the flow path switching device 120 does not circulate the refrigerant through the third heat exchanger 16, and circulates the refrigerant so that the second heat exchanger 9a acts as an evaporator and the first heat exchanger 3 acts as a condenser.

[0052] In the heating mode, the first four-way valve 2 is set to OFF (dashed line), the second four-way valve is set to ON (solid line), the on-off valve 5 is set to ON (open), the expansion valve 7 is set to ON (flow rate adjustment), and the expansion valve 19 is set to OFF (closed).

[0053] By being set in this manner, in heating mode, the flow path switching device 120 does not circulate refrigerant through the third heat exchanger 16, and circulates refrigerant so that the second heat exchanger 9a acts as a condenser and the first heat exchanger 3 acts as an evaporator.

[0054] In the hot water supply mode, the first four-way valve 2 is set to OFF (dashed line), the second four-way valve is set to OFF (dashed line), the on-off valve 5 is set to ON (open), the expansion valve 7 is set to OFF (closed), and the expansion valve 19 is set to ON (flow rate adjustment).

[0055] By being set in this manner, in the hot water supply mode, the flow path switching device 120 does not circulate the refrigerant through the second heat exchanger 9a, but circulates the refrigerant so that the first heat exchanger 3 acts as an evaporator and the third heat exchanger 16 acts as a condenser.

[0056] In the simultaneous cooling and hot water supply mode, the first four-way valve 2 is set to OFF (dashed line), the second four-way valve is set to OFF (dashed line), the on-off valve 5 is set to OFF (closed), the expansion valve 7 is set to ON (flow rate adjustment), and the expansion valve 19 is set to ON (flow rate adjustment).

[0057] By being set in this manner, in simultaneous mode, the flow path switching device 120 does not circulate refrigerant through the first heat exchanger 3, and circulates refrigerant so that the second heat exchanger 9a acts as an evaporator and the third heat exchanger 16 acts as a condenser.

[0058] In the defrosting mode, the first four-way valve 2 is set to ON (solid line), the second four-way valve is set to ON (solid line), the on-off valve 5 is set to ON (open), the expansion valve 7 is set to OFF (closed), and the expansion valve 19 is set to ON (flow rate adjustment).

[0059] By being set in this manner, in defrost mode, the flow path switching device 120 does not circulate refrigerant through the second heat exchanger 9a, but circulates refrigerant so that the first heat exchanger 3 acts as a condenser and the third heat exchanger 16 acts as an evaporator.

[0060] FIG. 4 is a diagram illustrating the flow of refrigerant in the cooling mode of the heat pump device according to the first embodiment.

[0061] In the cooling mode, the utilization devices 302a and 302b perform cooling. In the cooling mode, the flow path switching device 120 is set as shown in the cooling mode column in Figure 3, and the compressor 1, the outdoor blower 4, and the indoor blower 10 are activated.

[0062] As a result, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become a high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant then passes through the first four-way valve 2 and the first heat exchanger 3, where it is condensed and becomes a high-pressure liquid refrigerant through heat exchange with outdoor air supplied by the outdoor blower 4. After flowing out of the first heat exchanger 3, the high-pressure liquid refrigerant passes through the on-off valve 5 and is decompressed by the expansion valves 7a, 7b to become a low-pressure gas-liquid two-phase refrigerant, and then flows into the utilization devices 302a, 302b via the liquid pipes 8a, 8b.

[0063] The refrigerant that flows into the utilization devices 302a, 302b passes through the second heat exchangers 9a, 9b, and exchanges heat with the indoor air supplied by the indoor fans 10a, 10b, evaporating and becoming a low-pressure gas refrigerant. The degree of subcooling of the refrigerant on the liquid side of the first heat exchanger 3 is calculated by subtracting the temperature detected by the temperature sensor 204 from the condensation temperature. Here, the condensation temperature is the saturation temperature calculated from the pressure detected by the pressure sensor 201.

[0064] The expansion valves 7a, 7b control the flow rate of the refrigerant flowing through the second heat exchangers 9a, 9b so that the degree of subcooling of the refrigerant on the liquid side of the first heat exchanger 3 becomes a target value, and therefore the high-pressure liquid refrigerant condensed in the first heat exchanger 3 becomes in a state of having the target degree of subcooling. In this way, the refrigerant flows through the second heat exchangers 9a, 9b at a flow rate corresponding to the cooling load required in the air-conditioned space in which the utilization devices 302a, 302b are installed.

[0065] The refrigerant that has passed through the second heat exchangers 9a and 9b flows out of the utilization devices 302a and 302b, passes through the gas pipes 11a and 11b, and then merges at the junction / branch section 27 and flows into the gas pipe 12. The refrigerant then passes through the accumulator 14 via the second four-way valve 13 and is sucked into the compressor 1 again.

[0066] The operating frequency of compressor 1 is controlled by control device 110 so that there is no temperature difference between the indoor set temperature and the indoor suction temperature detected by temperature sensors 208a and 208b in utilization devices 302a and 302b. The air volume of outdoor blower 4 is controlled by control device 110 so that the condensing temperature becomes a target value according to the outdoor air temperature detected by outdoor air temperature sensor 205. Here, the condensing temperature is a saturation temperature calculated from the pressure detected by pressure sensor 201.

[0067] FIG. 5 is a diagram illustrating the flow of refrigerant in the heating mode of the heat pump device according to the first embodiment.

[0068] In the heating mode, the utilization devices 302a and 302b perform heating. In the heating mode, the flow path switching device 120 is set as shown in the heating mode column in Fig. 3, and the compressor 1, the outdoor blower 4, and the indoor blower 10 are activated.

[0069] As a result, the low-pressure gas refrigerant is sucked into the compressor 1 and compressed to become high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant then flows into the utilization devices 302a, 302b via the first four-way valve 2 and the second four-way valve 13. The refrigerant that has flowed into the utilization devices 302a, 302b passes through the second heat exchangers 9a, 9b, and exchanges heat with indoor air supplied by the indoor blowers 10a, 10b, causing it to condense and become high-pressure liquid refrigerant.

[0070] The high-pressure liquid refrigerant flows out of the second heat exchangers 9a, 9b, passes through liquid pipes 8a, 8b, and is reduced in pressure by expansion valves 7a, 7b to become low-pressure two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant then joins at the joining / branching section 28, passes through the on-off valve 5, and flows into the first heat exchanger 3. This two-phase gas-liquid refrigerant passes through the first heat exchanger 3 and exchanges heat with outdoor air supplied by the outdoor blower 4, evaporating and becoming low-pressure gas refrigerant. This low-pressure gas refrigerant passes through the accumulator 14 via the first four-way valve 2, and is again drawn into the compressor 1.

[0071] FIG. 6 is a diagram illustrating a flow of refrigerant in the hot water supply mode of the heat pump device according to the first embodiment.

[0072] In the hot water supply mode, the hot water supply unit 303 heats water in the hot water supply tank 304. In the hot water supply mode, the flow path switching device 120 is set as shown in the hot water supply mode column in Fig. 3 , and the compressor 1, the outdoor blower 4, and the pump 17 are activated.

[0073] As a result, the low-pressure gas refrigerant is sucked into compressor 1 and compressed to become high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant then passes through first four-way valve 2 and second four-way valve 13 and flows into hot water supply unit 303. The refrigerant that has flowed into hot water supply unit 303 passes through third heat exchanger 16 and exchanges heat with a liquid medium supplied by the liquid circulation path, condensing and becoming high-pressure liquid refrigerant.

[0074] The high-pressure liquid refrigerant flows out of the third heat exchanger 16, passes through the liquid pipe 18, and is decompressed by the expansion valve 19 to become a low-pressure gas-liquid two-phase refrigerant, and then passes through the on-off valve 5 and flows into the first heat exchanger 3. This gas-liquid two-phase refrigerant passes through the first heat exchanger 3 and exchanges heat with outdoor air supplied by the outdoor blower 4, evaporating and becoming a low-pressure gas refrigerant. This low-pressure gas refrigerant passes through the accumulator 14 via the first four-way valve 2 and is again drawn into the compressor 1.

[0075] FIG. 7 is a diagram illustrating the flow of refrigerant in the simultaneous mode of the heat pump device according to the first embodiment.

[0076] In the simultaneous mode, the utilization devices 302a and 302b perform cooling, and the hot water supply unit 303 heats the water in the hot water supply tank 304. In the simultaneous mode, the compressor 1, the indoor blower 10, and the pump 17 are started up with the flow path switching device 120 set as shown in the simultaneous mode column in Figure 3.

[0077] As a result, the low-pressure gas refrigerant is sucked into compressor 1 and compressed to become high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant then passes through first four-way valve 2 and second four-way valve 13 and flows into hot water supply unit 303. The refrigerant that has flowed into hot water supply unit 303 passes through third heat exchanger 16 and exchanges heat with a liquid medium supplied by the liquid circulation path, condensing and becoming high-pressure liquid refrigerant.

[0078] After flowing out of the third heat exchanger 16, the high-pressure liquid refrigerant passes through the liquid pipe 18, is decompressed by the expansion valve 19 and / or the expansion valves 7a, 7b, and becomes a low-pressure gas-liquid two-phase refrigerant, and then flows into the utilization devices 302a, 302b via the liquid pipes 8a, 8b.

[0079] The refrigerant that has flowed into the utilization devices 302a, 302b passes through the second heat exchangers 9a, 9b, and exchanges heat with the indoor air supplied by the indoor fans 10a, 10b, evaporating and becoming a low-pressure gas refrigerant.

[0080] The refrigerant that has passed through the second heat exchangers 9a and 9b flows out of the utilization devices 302a and 302b, passes through the gas pipes 11a and 11b, and then merges at the junction / branch section 27 to flow into the gas pipe 12, passes through the accumulator 14 via the second four-way valve 13, and is again sucked into the compressor 1.

[0081] In the simultaneous mode, the heat exhausted during cooling operation is used to heat water in the hot water supply unit 303, so there is no need to release the heat outdoors. Also, when the water temperature in the hot water tank is low, cooling can be performed more efficiently than if the heat exhausted outdoors is released.

[0082] FIG. 8 is a diagram illustrating the flow of refrigerant in the defrosting mode of the heat pump device according to the first embodiment.

[0083] In the defrost mode, heat from the hot water supply unit 303 is transferred to the first heat exchanger 3. In the defrost mode, the flow path switching device 120 is set as shown in the defrost mode column in Fig. 3 , and the compressor 1, the outdoor blower 4, and the pump 17 are activated.

[0084] As a result, the low-pressure gas refrigerant is sucked into compressor 1 and compressed to become high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant then passes through first four-way valve 2 and first heat exchanger 3, exchanging heat with outdoor air supplied by outdoor blower 4 and condensing to become high-pressure liquid refrigerant. After flowing out of first heat exchanger 3, the high-pressure liquid refrigerant passes through on-off valve 5 and is decompressed by expansion valve 19 to become low-pressure gas-liquid two-phase refrigerant, and then flows into hot water supply unit 303 via liquid piping 18. The refrigerant that has flowed into hot water supply unit 303 passes through third heat exchanger 16, exchanging heat with the liquid medium in the liquid circulation path and evaporating to become low-pressure gas refrigerant.

[0085] After flowing out of the third heat exchanger 16, the low-pressure gas refrigerant passes through the gas pipe 15 and the second four-way valve 13, passes through the accumulator 14, and is sucked into the compressor 1 again.

[0086] In the defrosting mode shown in FIG. 8, refrigerant is not circulated through the utilization devices 302a and 302b, so that it is possible to prevent cold air from being blown into a room that has been heated during defrosting operation.

[0087] FIG. 9 is a flowchart showing switching control between the cooling mode and the simultaneous mode in the heat pump device of the first embodiment.

[0088] In step S1, control device 110 determines whether or not there is a request for boiling water. If the temperature detected by water temperature sensors 212-215 of hot water tank 304 indicates that the water in hot water tank 304 needs to be heated, a boiling request is present. Specifically, for example, if the temperature detected by water temperature sensors 212-215 is lower than the hot water supply setting temperature, it is determined that there is a boiling request, and if the detected temperature is higher than the hot water supply setting temperature, it is determined that there is no boiling request.

[0089] If there is no request for heating (NO in S1), the control device 110 selects the cooling mode in step S2, controls each element as shown in the cooling mode column of FIG.

[0090] On the other hand, if there is a request for heating (YES in S1), in step S3, the control device 110 determines whether or not there is a request for hot water. A hot water request is made when the user opens the hot water tap, for example. Specifically, for example, a flow rate sensor is provided in the water supply pipe at the inlet or the hot water supply pipe at the outlet of the hot water tank 304, and if the detected flow rate exceeds a judgment value, it is determined that there is a hot water request, and if the detected flow rate does not exceed the judgment value, it is determined that there is no hot water request.

[0091] If there is no hot water supply request (NO in S3), in step S4, the control device 110 determines whether the difference ΔT between the room temperature and the set temperature is equal to or less than a determination value (for example, 10° C.).

[0092] If the difference ΔT between the indoor temperature and the set temperature is greater than the judgment value (NO in S4), the cooling mode is selected in step S5, and indoor comfort is prioritized. In step S5, the control device 110 controls each element as shown in the cooling mode column in Figure 3 to operate the heat pump device 100.

[0093] On the other hand, if the difference ΔT between the room temperature and the set temperature is equal to or less than the judgment value (YES in S4), the control device 110 selects the simultaneous mode in which cooling and hot water are performed simultaneously, prioritizing energy conservation in step S6. In step S6, the control device 110 controls each element as shown in the simultaneous mode column in Figure 3 to operate the heat pump device 100.

[0094] The judgment value for ΔT (=room temperature−set temperature) is not limited to 10° C. and should preferably be changed depending on the hot water supply load (set hot water temperature or tank capacity).

[0095] If a hot water supply request is made in step S3 (YES in S3), the control device 110 selects the hot water supply mode in step S7. In step S7, the control device 110 controls each element as shown in the hot water supply mode column in FIG. 3 to operate the heat pump device 100.

[0096] At this time, in step S8, the control device 110 determines whether or not the water heating is complete. If both a water heating request and a hot water supply request are present, there is a possibility that the hot water supply requested by the user cannot be performed due to a lack of hot water, so only the hot water supply operation is performed with priority. Specifically, for example, if the temperature detected by the water temperature sensors 212 to 215 is lower than the hot water supply setting temperature, it is determined that the water heating is not complete, and if the detected temperature is higher than the hot water supply setting temperature, it is determined that the water heating is complete.

[0097] If the water heating is not completed (NO in S8), the process returns to step S7 and operation in the hot water supply mode continues. On the other hand, if the water heating is completed (YES in S8), a determination is made in step S9 as to whether or not to switch to the simultaneous mode under the same conditions as in step S4.

[0098] If the difference ΔT between the indoor temperature and the set temperature is greater than the judgment value (NO in S9), the cooling mode is selected in step S10, and indoor comfort is prioritized. In step S10, the control device 110 controls each element as shown in the cooling mode column in Figure 3 to operate the heat pump device 100.

[0099] On the other hand, if the difference ΔT between the room temperature and the set temperature is equal to or less than the judgment value (YES in S9), the control device 110 selects simultaneous mode in which cooling and hot water supply are performed simultaneously in step S11, prioritizing energy conservation. By increasing the operating time in simultaneous mode, it is possible to reduce the operating time in independent operation (cooling mode, hot water supply mode). This makes it possible to shorten the total operating time of the heat pump device, contributing to reducing annual power consumption. In step S11, the control device 110 controls each element as shown in the simultaneous mode column of Figure 3 to operate the heat pump device 100.

[0100] 10 is a flowchart showing switching control during heating operation of the heat pump apparatus of embodiment 1. In a defrosting operation performed during heating operation, if the defrosting operation is performed at an inappropriate timing, frost formation may occur, resulting in a decrease in performance and a loss of energy saving. Therefore, in embodiment 1, the defrosting operation is performed at an appropriate timing based on the frost formation determination conditions.

[0101] First, in step S11, control device 110 determines whether or not there is a water heating request. If the temperature detected by water temperature sensors 212-215 of hot water tank 304 indicates that the water in hot water tank 304 needs to be heated, a water heating request is present. Specifically, for example, if the temperature detected by water temperature sensors 212-215 is lower than the hot water supply set temperature, it is determined that there is a water heating request, and if the detected temperature is higher than the hot water supply set temperature, it is determined that there is no water heating request.

[0102] If there is no request for heating (NO in S11), the control device 110 selects the heating mode in step S2, controls each element as shown in the heating mode column of FIG.

[0103] On the other hand, if there is a request for heating (YES in S11), the control device 110 selects the hot water supply mode in step S13. In step S13, the control device 110 controls each element as shown in the hot water supply mode column in FIG. 3 to operate the heat pump device 100.

[0104] Next, in step S14, the control device determines whether the operating time in the heating mode or the hot water supply mode is longer than a predetermined time (for example, one hour). Note that one hour is an example, and the predetermined time may be changed as appropriate depending on the usage environment and conditions.

[0105] If the operating time is equal to or less than the determination time (NO in S14), there is no risk of frost formation, so the process of this flowchart is terminated and it is determined again in step S11 whether to select the heating mode or the hot water supply mode.

[0106] If the operating time is longer than the determination time (YES in S14), a determination is made in step S15 as to whether frost has formed on the outdoor heat exchanger. The condition for determining whether frost has formed is T1 > T2. T1 and T2 are determined as follows: T1 = outdoor air temperature - refrigerant temperature T2 = 5°C (when outdoor air temperature ≥ 0°C) T2 = 3°C (when -10°C ≤ outdoor air temperature < 0°C) T2 = 1°C (when outdoor air temperature < -10°C) If T1 ≤ T2 (NO in S15), there is no risk of frost formation, so the process exits from this flowchart, and a determination is made again in step S11 as to whether to select heating mode or hot water supply mode.

[0107] If T1>T2 (YES in S15), there is a risk of frost formation, so in step S16, control device 110 selects defrost mode and controls each element as shown in the defrost mode column in Figure 3 to operate heat pump device 100. Then, in step S17, control device 110 determines whether or not boiling is complete. Specifically, for example, if the temperature detected by water temperature sensors 212-215 is lower than the hot water supply temperature setting, it is determined that boiling is not complete, and if the detected temperature is higher than the hot water supply temperature setting, it is determined that boiling is complete.

[0108] If the water heating is not completed (NO in S17), the process returns to step S13 and operation in the hot water supply mode continues. On the other hand, if the water heating is completed (YES in S17), the process of this flowchart is temporarily terminated, and a determination is made again in step S11 as to whether to select the heating mode or the hot water supply mode.

[0109] The operating time in step S14 and the temperature of the frost formation determination condition in step S15 are not limited to the values ​​shown as examples, and can be changed depending on the installation location, etc. Furthermore, the determinations in steps S14 and S15 may be made simply based on the elapsed operating time.

[0110] As described above, according to the heat pump device of embodiment 1, by appropriately switching between operation modes, it is possible to achieve both comfort and energy conservation by switching between various operation modes without compromising indoor comfort.

[0111] Second Embodiment Fig. 11 is a diagram showing the configuration of a heat pump device according to a second embodiment.

[0112] Heat pump apparatus 100A shown in Fig. 11 includes heat source apparatus 301A, branching apparatus 306, utilization apparatuses 302a and 302b, and hot water supply unit 303. Hot water supply unit 303 heats water in hot water supply tank 304 shown in Fig. 2. Utilization apparatuses 302a and 302b, hot water supply unit 303, and hot water supply tank 304 have the same configuration as those shown in Fig. 1, and therefore description thereof will not be repeated.

[0113] In the second embodiment, the components of the flow path switching device 120 are arranged separately in a heat source device 301A and a branching device 306.

[0114] Specifically, the heat source device 301A and the branching device 306 are connected by a liquid extension pipe 6, which is a refrigerant pipe, and a gas pipe 12, which is also a refrigerant pipe. The hot water supply unit 303 is connected to the heat source device 301 via a gas pipe 15, which is also a refrigerant pipe, on one side, and to the branching device 306 via a liquid pipe 18, which is also a refrigerant pipe on the other side. The utilization devices 302a and 302b and the branching device 306 are connected by gas pipes 11a and 11b, which are refrigerant pipes, and liquid pipes 8a and 8b, which are refrigerant pipes.

[0115] The first four-way valve 2 and the second four-way valve 13 constitute a part of a flow path switching device that switches the direction of the refrigerant flow depending on the operation mode of the heat pump device 100A.

[0116] Of the components of the flow path switching device, the first four-way valve 2, the second four-way valve 13, and the on-off valve 5 are arranged in the heat source device 301A.

[0117] Of the components of the flow path switching device, the first expansion valves 7a, 7b and the second expansion valve 19 are arranged in a branching device 306. One ends of the first expansion valves 7a, 7b and the second expansion valve 19 are connected to a junction / branch section 28 inside the branching device 306 and then connected to the liquid extension pipe 6. The other ends of the first expansion valves 7a, 7b and the second expansion valve 19 are connected to liquid pipes 8a, 8b and the liquid pipe 18, respectively. Furthermore, a junction / branch section 27 that joins the gas pipes 11a, 11b and connects them to the gas pipe 12 is also arranged in the branching device 306.

[0118] The other components shown in FIG. 11 are connected in the same manner as in FIG. 1, and therefore description thereof will not be repeated here.

[0119] Furthermore, the operation modes described with reference to FIGS. 3 to 8 and the operation mode switching control described with reference to FIGS. 9 and 10 are similar to those in the second embodiment, and therefore description thereof will not be repeated.

[0120] According to the second embodiment, since a part of the flow path switching device is distributed to the branching device, the heat source device to be placed outdoors can be made smaller. In addition, the extension pipes can be bundled partway, which makes it possible to reduce the number of pipes.

[0121] [Summary] (Section 1) The present disclosure relates to a heat pump device 100. The heat pump device 100 has operating modes including a cooling mode, a hot water supply mode, and a simultaneous mode in which cooling and hot water supply are performed simultaneously. The heat pump device includes a compressor 1 that compresses a refrigerant, a first heat exchanger 3 that exchanges heat between the refrigerant and outdoor air, a second heat exchanger 9a that exchanges heat between the refrigerant and indoor air, a third heat exchanger 16 that is connected to a liquid circulation path 130 through which a liquid medium for heating water in a hot water tank 304 circulates and exchanges heat between the liquid medium and the refrigerant, a flow path switching device 120 that can change the flow path through which the refrigerant flows among the compressor 1, the first heat exchanger 3, the second heat exchanger 9a, and the third heat exchanger 16, and a control device 110 that controls the flow path switching device 120. In the hot water supply mode, the flow path switching device 120 does not circulate refrigerant through the second heat exchanger 9a, and circulates refrigerant so that the first heat exchanger 3 functions as an evaporator and the third heat exchanger 16 functions as a condenser. In the simultaneous mode, the flow path switching device 120 does not circulate refrigerant through the first heat exchanger 3, and circulates refrigerant so that the second heat exchanger 9a functions as an evaporator and the third heat exchanger 16 functions as a condenser. The control device 110 is configured to select the hot water supply mode when it is necessary to heat water in the hot water tank 304 and there is a hot water supply request, to select either the cooling mode or the simultaneous mode when it is necessary to heat water in the hot water tank 304 and there is no hot water supply request, and to select the cooling mode when it is not necessary to heat water in the hot water tank 304.

[0122] (Clause 2) In the heat pump device described in clause 1, the control device 110 is configured to select either the cooling mode or the simultaneous mode of operation based on the difference between the set temperature and the room temperature when it is necessary to heat the water in the hot water tank 304 and there is no request for hot water supply, as shown in Figure 9.

[0123] (Clause 3) In the heat pump device described in clause 2, the control device 110 is configured to select the simultaneous mode when the difference between the indoor temperature and the set temperature is smaller than the first judgment threshold, as shown in Figure 9, and to select the cooling mode when the difference between the indoor temperature and the set temperature is larger than the first judgment threshold.

[0124] (4) In the heat pump apparatus according to any one of paragraphs 1 to 3, the heat pump apparatus 100 further has a heating mode and a defrost mode as operation modes. In the heating mode, the flow path switching device 120 does not circulate the refrigerant through the third heat exchanger 16, and circulates the refrigerant so that the first heat exchanger 3 functions as an evaporator and the second heat exchanger 9a functions as a condenser. In the defrost mode, the flow path switching device 120 does not circulate the refrigerant through the second heat exchanger 9a, and circulates the refrigerant so that the first heat exchanger 3 functions as a condenser and the third heat exchanger 16 functions as an evaporator. As shown in FIG. 10 , the control device 110 is configured to select the hot water supply mode when water in the hot water tank 304 needs to be heated, and to select the defrost mode when a frost formation determination condition is met while the hot water supply mode or the heating mode is selected.

[0125] (5) In the heat pump device described in 4, as shown in step S15 of Figure 10, the frost formation determination condition includes that the difference between the outside air temperature and the temperature of the refrigerant flowing through the first heat exchanger 3 is greater than a second determination threshold.

[0126] (Item 6) In the heat pump apparatus according to item 5, as shown in step S14 of FIG. 10, the frost formation determination condition further includes that the operating time during which the heating mode or the hot water supply mode is selected is longer than the determination time.

[0127] (Item 7) In the heat pump apparatus described in any one of Items 1 to 5, the flow path switching device 120 includes a first four-way valve 2, a second four-way valve 13, a first expansion valve 7a, a second expansion valve 19, and an on-off valve 5. The first four-way valve 2 has a first port P1 to a fourth port P4. The second four-way valve 13 has a fifth port P5 to an eighth port P8. The first port P1 is coupled to the discharge side of the compressor 1. The second port P2 is connected to one end of the first heat exchanger 3. One end of the on-off valve 5 is connected to the other end of the first heat exchanger 3. The first expansion valve 7a is connected between the other end of the on-off valve 5 and one end of the second heat exchanger 9a. The second expansion valve 19 is connected between the other end of the on-off valve 5 and one end of the third heat exchanger 16. The third port P3 and the seventh port P7 are coupled to the suction side of the compressor 1. The fourth port P4 is connected to the fifth port P5. The sixth port P6 is connected to the other end of the second heat exchanger 9a. The eighth port P8 is connected to the other end of the third heat exchanger 16.

[0128] (Item 8) The heat pump apparatus according to item 7 further includes a heat source device 301, as shown in Fig. 1. The compressor 1, the first heat exchanger 3, and the flow switching device 120 are disposed in the heat source device 301.

[0129] (Item 9) The heat pump apparatus according to item 7 further includes a heat source apparatus 301A and a branching apparatus 306, as shown in Fig. 11. The compressor 1, the first heat exchanger 3, the first four-way valve 2, the second four-way valve 13, and the on-off valve 5 are arranged in the heat source apparatus 301A. The first expansion valve 7a and the second expansion valve 19 are arranged in the branching apparatus 306.

[0130] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0131] 1 Compressor, 2, 13 Four-way valve, 3, 9a, 9b, 16 Heat exchanger, 4 Outdoor blower, 5 On-off valve, 6 Liquid extension piping, 7, 7a, 7b, 19 Expansion valve, 8a, 8b, 18 Liquid piping, 10, 10a, 10b Indoor blower, 11a, 11b, 12, 15 Gas piping, 14 Accumulator, 17 Pump, 20 Water upstream piping, 21 Water downstream piping, 27, 28 Confluence / branching section, 100, 100A Heat pump device, 110 Control device, 120 Switching device, 130 Liquid circulation path, 201 Pressure sensor, 202-205, 206a, 206b, 207a, 207b, 208a, 208b, 209 Temperature sensor, Outdoor air temperature sensor, 212-216 Water temperature sensor, 301, 301A heat source device, 302a, 302b utilization device, 303 hot water supply unit, 304 hot water supply tank, 306 branching device, P1-P8 ports.

Claims

1. A heat pump apparatus having a cooling mode, a hot water supply mode, and a simultaneous mode in which cooling and hot water supply are performed simultaneously as operating modes, comprising: a compressor that compresses a refrigerant; a first heat exchanger that performs heat exchange between the refrigerant and outdoor air; a second heat exchanger that performs heat exchange between the refrigerant and indoor air; a third heat exchanger connected to a liquid circulation path through which a liquid medium for heating water in a hot water supply tank circulates, the third heat exchanger performing heat exchange between the liquid medium and the refrigerant; a flow path switching device capable of changing a flow path through which the refrigerant flows through the compressor, the first heat exchanger, the second heat exchanger, and the third heat exchanger; and a control device that controls the flow path switching device. In the hot water supply mode, the flow path switching device does not allow the refrigerant to flow through the second heat exchanger, and causes the refrigerant to flow such that the first heat exchanger acts as an evaporator and the third heat exchanger acts as a condenser. In the simultaneous mode, the flow path switching device does not allow the refrigerant to flow through the first heat exchanger, and causes the refrigerant to flow such that the second heat exchanger acts as an evaporator and the third heat exchanger acts as a condenser. The control device is configured to select the hot water supply mode when there is a need to heat the water in the hot water supply tank and there is a hot water supply request, to select either the cooling mode or the simultaneous mode when there is a need to heat the water in the hot water supply tank but there is no hot water supply request, and to select the cooling mode when there is no need to heat the water in the hot water supply tank.

2. The heat pump apparatus according to claim 1, wherein the control device is configured to select either the cooling mode or the simultaneous mode based on a difference between a set temperature and an indoor temperature when there is a need to heat the water in the hot water supply tank but there is no hot water supply request.

3. The heat pump apparatus according to claim 2, wherein the control device is configured to select the simultaneous mode when a difference between the indoor temperature and the set temperature is smaller than a first determination threshold value, and to select the cooling mode when the difference between the indoor temperature and the set temperature is larger than the first determination threshold value.

4. The heat pump device further has a heating mode and a defrosting mode as operating modes. In the heating mode, the flow path switching device does not allow the refrigerant to flow through the third heat exchanger, and causes the refrigerant to flow such that the first heat exchanger acts as an evaporator and the second heat exchanger acts as a condenser. In the defrosting mode, the flow path switching device does not allow the refrigerant to flow through the second heat exchanger, and causes the refrigerant to flow such that the first heat exchanger acts as a condenser and the third heat exchanger acts as an evaporator. The control device is configured to select the hot water supply mode when it is necessary to heat the water in the hot water supply tank, and to select the defrosting mode when the frost formation determination condition is satisfied during the selection of the hot water supply mode or the heating mode. The heat pump device according to any one of claims 1 to 3.

5. The frost formation determination condition includes that the difference between the outside air temperature and the temperature of the refrigerant flowing through the first heat exchanger is greater than a second determination threshold value. The heat pump device according to claim 4.

6. The frost formation determination condition further includes that the operating time during the selection of the heating mode or the hot water supply mode is longer than the determination time. The heat pump device according to claim 5.

7. The flow path switching device includes a first four-way valve, a second four-way valve, a first expansion valve, a second expansion valve, and an on-off valve. The first four-way valve has first to fourth ports. The second four-way valve has fifth to eighth ports. The first port is connected to the discharge side of the compressor. The second port is connected to one end of the first heat exchanger. One end of the on-off valve is connected to the other end of the first heat exchanger. The first expansion valve is connected between the other end of the on-off valve and one end of the second heat exchanger. The second expansion valve is connected between the other end of the on-off valve and one end of the third heat exchanger. The third port and the seventh port are connected to the suction side of the compressor. The fourth port is connected to the fifth port. The sixth port is connected to the other end of the second heat exchanger. The eighth port is connected to the other end of the third heat exchanger. The heat pump device according to any one of claims 1 to 5.

8. The heat pump device according to claim 7, further comprising a heat source device, wherein the compressor, the first heat exchanger, and the flow path switching device are arranged in the heat source device.

9. The heat pump device according to claim 7, further comprising a heat source device and a branching device, wherein the compressor, the first heat exchanger, the first four-way valve, the second four-way valve, and the on-off valve are arranged in the heat source device, and the first expansion valve and the second expansion valve are arranged in the branching device.

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