Heat pump device

Abstract

This disclosure provides a heat pump device capable of simultaneously performing cooling operation and hot water storage operation, which heats water in a hot water storage tank. [Solution] The heat pump device 1 comprises a refrigerant circuit 11, an electric heater EH, a switching valve Vt, and a control unit 15. The electric heater EH is located inside the hot water storage tank HWT, which houses a heat exchange coil HC provided in a branch pipeline 17 that branches off from a utilization pipeline 13 that passes the utilization fluid Fu through the first heat exchanger 112 of the refrigerant circuit 11. The switching valve Vt is provided in the utilization pipeline 13 and switches between a first state that connects the upstream and downstream sides of the utilization pipeline 13 and a second state that connects the upstream side of the utilization pipeline 13 to the branch pipeline 17. The control unit 15 controls the switching mechanism 116 of the refrigerant circuit 11 to perform cooling operation, and at the same time controls the switching valve Vt to the first state, energizing the electric heater EH to perform a first mode that heats the water stored in the hot water storage tank HWT.

Description

Technical Field

[0004]

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

Background Art

[0002] Conventionally, an air conditioner that performs hot water supply operation using an auxiliary heater has been known (for example, see Patent Document 1). The air conditioner described in Patent Document 1 includes a heat source machine, an air conditioning unit, a hot water supply unit, and a control unit.

[0003] The heat source machine includes a refrigerant cycle that circulates a refrigerant. The air conditioning unit performs heating operation and cooling operation by exchanging heat between the refrigerant and indoor air. The hot water supply unit includes a hot water storage tank and performs hot water supply operation by heating with the refrigerant. The control unit performs a first alternating operation of alternately performing heating operation and hot water supply operation when a heating request and a hot water supply request are output simultaneously, and performs a second alternating operation of alternately performing cooling operation and hot water supply operation when a cooling request and a hot water supply request are output simultaneously. Further, the control unit performs control so that a first continuous operation time of the hot water supply operation in the first alternating operation is different from a second continuous operation time of the hot water supply operation in the second alternating operation.

[0004] Patent Document 1 states that with the above configuration, even in an air conditioner that performs hot water supply operation using an auxiliary heater, it is possible to suppress an increase in power consumption and suppress a decrease in indoor comfort.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] <The air conditioning system described in Patent Document 1 prohibits the start of heating by the heating section of the hot water supply unit when cooling operation is being performed in the second alternating operation. Therefore, the air conditioning system of Patent Document 1 cannot perform cooling operation and hot water supply operation simultaneously.

[0007] This disclosure provides a heat pump device capable of simultaneously performing cooling operation and hot water storage operation, which heats water in a hot water storage tank. [Means for solving the problem]

[0008] A first aspect of this disclosure includes a refrigerant circuit (11) that performs a refrigeration cycle, comprising a compressor (111) for compressing a refrigerant (Fr), a first heat exchanger (112) for exchanging heat between the refrigerant (Fr) and a heat source fluid (Fh), a pressure reducing mechanism (113) for reducing the pressure of the refrigerant (Fr), a second heat exchanger (114) for exchanging heat between the refrigerant (Fr) and a utilization fluid (Fu), and a switching mechanism (116) that can switch between a cooling operation in which the flow direction of the refrigerant (Fr) is switched so that the second heat exchanger (114) functions as an evaporator and a heating operation in which the second heat exchanger (114) functions as a heat radiator, and a utilization pipeline (13) that branches off from the utilization pipeline (13) through which the utilization fluid (Fu) passes to the second heat exchanger (114). The present invention provides a heat pump device (1) comprising: an electric heater (EH) located inside a hot water storage tank (HWT) that houses a heat exchange coil (HC) installed in a branch pipeline (17); a switching valve (Vt) provided in the utilization pipeline (13) that can switch between a first state in which the upstream and downstream sides of the utilization pipeline (13) are connected and a second state in which the upstream side of the utilization pipeline (13) is connected to the branch pipeline (17); and a control unit (15) that controls the switching mechanism (116) to perform the cooling operation and at the same time controls the switching valve (Vt) to the first state, energizes the electric heater (EH) to heat the water stored in the hot water storage tank (HWT), thereby executing a first mode.

[0009] According to the first point of view described above, a heat pump device (1) can be provided that can simultaneously perform cooling operation and hot water storage operation, which heats the water in the hot water storage tank (HWT).

[0010] A second aspect of this disclosure is that, in the heat pump device (1) according to the first aspect, the control unit (15) may, at the same time as controlling the switching mechanism (116) to perform the heating operation, control the switching valve (Vt) to the second state and execute a second mode in which the utilization fluid (Fu) is passed through the heat exchange coil (HC) to heat the water stored in the hot water storage tank (HWT).

[0011] From the second point of view described above, during heating operation, the working fluid (Fu), whose temperature has risen due to heat exchange with the refrigerant (Fr), is passed through the heat exchange coil (HC), and the water stored in the hot water storage tank (HWT) can be heated by heat exchange with the working fluid (Fu). Therefore, during heating operation, hot water storage operation can be performed without energizing the electric heater (EH), and the power consumption of hot water storage operation can be reduced.

[0012] A third aspect of this disclosure is that, in the heat pump device (1) according to the first or second aspect, the control unit (15) may, in the first mode, perform a cooling-priority operation in which it supplies power to the compressor (111) from the available power according to the load of the refrigeration cycle and supplies the surplus power to the electric heater (EH).

[0013] From the third point of view described above, in the first mode in which cooling operation and hot water storage operation are performed simultaneously, available power can be preferentially supplied to the compressor (111) of the refrigerant circuit (11). This makes it possible to perform cooling operation according to the load of the refrigeration cycle of the refrigerant circuit (11), such as the cooling load from an air conditioning system using the working fluid (Fu). In addition, by supplying surplus power to the electric heater (EH), cooling operation and hot water storage operation can be performed simultaneously without reducing the cooling capacity of the heat pump device (1).

[0014] A fourth aspect of this disclosure is that in the heat pump device (1) according to any one of the first to third aspects described above, the electric heater (EH) may be located in the upper half (UH) of the hot water storage tank (HWT).

[0015] From the fourth point of view described above, the water stored in the upper half (UH) of the hot water storage tank (HWT) can be preferentially heated by the electric heater (EH) located in the upper half (UH) of the hot water storage tank (HWT). This allows the temperature of the water stored in the upper half (UH) to be raised with less power compared to heating the water stored in the entire hot water storage tank (HWT). Therefore, even when cooling-priority operation is performed in the first mode, which performs cooling and hot water storage operation simultaneously, hot water (HW) at the desired temperature can be supplied from the upper half (UH) of the hot water storage tank (HWT).

[0016] A fifth aspect of this disclosure is that, in the heat pump device (1) according to the first or second aspect, the control unit (15) may, in the first mode, perform a hot water priority operation in which it supplies the power necessary for heating the water stored in the hot water storage tank (HWT) from the available power to the electric heater (EH) and supplies the surplus power to the compressor (111).

[0017] From the fifth point of view described above, in the first mode, which performs cooling and hot water storage operations simultaneously, available power can be preferentially supplied to the electric heater (EH). This makes it possible to generate hot water HW at the required temperature in a short time. Furthermore, by supplying surplus power to the compressor (111) of the refrigerant circuit (11), cooling and hot water storage operations can be performed simultaneously without reducing the hot water (HW) generation capacity of the electric heater (EH).

[0018] A sixth aspect of this disclosure is that, in the heat pump device (1) according to the first or second aspect, the control unit (15) may switch between, in the first mode, a cooling-priority operation in which power corresponding to the load of the refrigeration cycle is supplied to the compressor (111) from the available power and the surplus power is supplied to the electric heater (EH), and a hot water-priority operation in which power necessary for heating the water stored in the hot water storage tank (HWT) is supplied to the electric heater (EH) from the available power and the surplus power is supplied to the compressor (111).

[0019] Based on the sixth point of view described above, the heat pump device (1) can be switched between cooling-priority operation and hot water-priority operation depending on the situation. This makes it possible to perform cooling operation and hot water storage operation simultaneously in the first mode without reducing the hot water (HW) generation capacity of the electric heater (EH), or to perform cooling operation and hot water storage operation simultaneously without reducing the cooling capacity of the heat pump device (1).

[0020] A seventh aspect of this disclosure is that the heat pump device (1) according to the sixth aspect further comprises a water temperature sensor (TI5) for detecting the temperature of hot water (HW) stored in the hot water storage tank (HWT), and the control unit (15) may perform the hot water priority operation when the temperature of the hot water (HW) detected by the water temperature sensor (TI5) is below a predetermined temperature.

[0021] From the seventh point of view described above, if the temperature of the hot water (HW) detected by the water temperature sensor (TI5) falls below a predetermined temperature and there is insufficient hot water (HW) stored in the hot water storage tank (HWT), a hot water priority operation can be performed to quickly generate hot water (HW).

[0022] The eighth aspect of this disclosure is that, in the heat pump device (1) according to the sixth aspect, the control unit (15) may perform the cooling priority operation when an indicator relating to the load of the utilization circuit (3) connected to the utilization pipeline (13) is equal to or greater than a predetermined value.

[0023] From the perspective of the eighth point described above, for example, if the cooling load from the air conditioning equipment using the utilization fluid (Fu) increases and the indicator for the load of the utilization circuit (3) connected to the utilization pipeline (13) exceeds a predetermined value, cooling priority operation can be performed to supply power to the compressor (111) of the refrigerant circuit (11) in accordance with the load of the utilization circuit (3). As a result, the heat pump device (1) can exert a cooling capacity corresponding to the cooling load.

[0024] A ninth aspect of this disclosure is that, in the heat pump device (1) according to the second aspect, the control unit (15) may periodically execute the second mode in the event of a failure of the electric heater (EH).

[0025] According to the ninth aspect described above, even when the electric heater (EH) fails, the control unit (15) can periodically execute the second mode during the cooling operation. Thereby, the control unit (15) performs a heating operation during the intervals of the cooling operation of the refrigerant circuit (11) to allow the utilization fluid (Fu) to pass through the heat exchange coil (HC), and can suppress a decrease in the temperature of the hot water (HW) stored in the hot water storage tank (HWT).

[0026] A tenth aspect of the present disclosure is that in the heat pump device (1) according to the fifth aspect described above, the electric heater (EH) may be disposed in the lower half portion (LH) of the hot water storage tank (HWT).

[0027] According to the tenth aspect described above, the water stored in the lower half portion (LH) of the hot water storage tank (HWT) can be heated by the electric heater (EH) to cause convection in the water stored in the hot water storage tank (HWT). Thereby, the water stored in the hot water storage tank (HWT) can be heated as a whole including the lower half portion (LH) where low-temperature water tends to stagnate, and hot water (HW) can be generated.

[0028] An eleventh aspect of the present disclosure is that in the heat pump device (1) according to the third or fifth aspect described above, the electric heater (EH) may include an upper heater (UEH) disposed in the upper half portion (UH) of the hot water storage tank (HWT) and a lower heater (LEH) disposed in the lower half portion (LH) of the hot water storage tank (HWT).

[0029] According to the eleventh aspect described above, the water stored in the upper half portion (UH) of the hot water storage tank (HWT) can be preferentially heated by the upper heater (UEH). Thereby, the temperature of the water stored in the upper half portion (UH) can be increased with less power as compared with the case of heating the water stored in the hot water storage tank (HWT) as a whole. Further, the water stored in the lower half portion (LH) of the hot water storage tank (HWT) can be heated by the lower heater (LEH). Thereby, convection can be caused in the water stored in the hot water storage tank (HWT), and the water stored in the hot water storage tank (HWT) can be heated as a whole to generate hot water (HW).

[0030] A twelfth aspect of this disclosure is the heat pump device (1) according to any one of the first to eleventh aspects described above, wherein the refrigerant (Fr) is a flammable gas with a specific gravity greater than air at atmospheric pressure, and the electrical connection (EC) of the electric heater (EH) may be located above the hot water storage tank (HWT).

[0031] From the perspective of the 12th point above, the safety of the heat pump device (1) can be improved in the event that the refrigerant (Fr) leaks from the refrigerant circuit (11). Specifically, since the refrigerant (Fr) has a higher specific gravity than air, it will accumulate below the heat pump device 1 if it leaks from the refrigerant circuit (11). Therefore, by placing the electrical connection part (EC) of the electric heater (EH) above the hot water storage tank (HWT), contact between the electrical connection part (EC) of the electric heater (EH) and the flammable refrigerant (Fr) can be avoided. [Brief explanation of the drawing]

[0032] [Figure 1] A circuit diagram showing an embodiment of the heat pump device (1) according to this disclosure. [Figure 2] An enlarged view of the area around the hot water storage tank (HWT) in the circuit diagram shown in Figure 1. [Figure 3] A flowchart of the processing of the control unit (15) that constitutes the heat pump device (1) in Figure 1. [Figure 4] A flowchart showing the details of the process (P5) that executes the first mode in Figure 3. [Modes for carrying out the invention]

[0033] Hereinafter, embodiments of the heat pump device (1) according to this disclosure will be described with reference to the drawings. Figure 1 is a circuit diagram showing an embodiment of the heat pump device (1) according to this disclosure. The heat pump device 1 shown in Figure 1 is, for example, part of a heat pump system including a heat source circuit 2 and a utilization circuit 3. The heat pump device 1 uses the cold energy of the heat source fluid Fh circulating in the heat source circuit 2 to heat or cool the utilization fluid Fu circulating in the utilization circuit 3.

[0034] The heat source circuit 2 is part of the heat pump system and circulates the heat source fluid Fh to the heat pump device 1. The heat source circuit 2 includes heat source conduits 24 and 25 connected to the heat pump device 1. The heat source conduits 24 and 25 are equipped with on / off valves at the ends connected to the heat pump device 1, for example. The heat source circuit 2 also includes a heat source section (not shown) and a heat source pump.

[0035] The heat source section of the heat source circuit 2 uses, for example, air heat, geothermal heat, waste heat, river water, or factory wastewater as a heat source, and heats or cools the heat source fluid Fh, which is recovered via the return heat source pipeline 25 of the heat source circuit 2, to a predetermined temperature range before supplying it to the outgoing heat source pipeline 24 of the heat source circuit 2. As the heat source fluid Fh, for example, a liquid such as water or brine can be used. The heat source section includes, for example, one or more air heat source heat pump chillers. The heat source section is installed, for example, in a heat source fluid Fh supply facility located away from a house or office building where the heat pump device 1 is installed.

[0036] The heat source pump of the heat source circuit 2 is provided, for example, in the supply heat source pipeline 24 that connects the heat source unit and each heat source heat exchanger 7. Alternatively, the heat source pump may be provided in the return heat source pipeline 25 that connects the heat pump device 1 and the heat source unit. The heat source pump circulates the heat source fluid Fh to the heat source circuit 2 via the heat source pipelines 24 and 25 by pressurizing the heat source fluid Fh.

[0037] The utilization circuit 3 is part of the heat pump system and circulates the utilization fluid Fu to the heat pump device 1. The utilization circuit 3 includes, for example, a utilization section 31 that utilizes the cold energy of the utilization fluid Fu, and a utilization pipeline 32 connected to the heat pump device 1 that circulates the utilization fluid Fu to the utilization section 31. As the utilization fluid Fu circulated in the utilization circuit 3, for example, a liquid such as water or brine can be used.

[0038] Furthermore, the utilization circuit 3 includes, for example, a water supply pipe 33, a hot water supply pipe 34, and hot water utilization equipment such as a shower Sh. The utilization pipe 32, water supply pipe 33, and hot water supply pipe 34 of the utilization circuit 3 are equipped with on / off valves at the ends connected to the heat pump device 1, for example.

[0039] The utilization section 31 is located in the middle of the utilization pipeline 32, and the utilization fluid Fu is supplied through the utilization pipeline 32. The utilization section 31 includes, for example, a radiator 311 or underfloor heating and cooling system 312 installed inside a house or office. The utilization pipeline 32 includes a supply pipe connected to the inlet of the utilization fluid Fu at each utilization section 31, and a return pipe connected to the outlet of the utilization fluid Fu at each utilization section 31.

[0040] The water supply pipe 33 is connected to the heat pump device 1 and supplies tap water TW to the hot water storage tank HWT, which will be described later. The hot water supply pipe 34 is connected to the heat pump device 1 and supplies hot water HW from the hot water storage tank HWT, which will be described later, to hot water utilization equipment such as showers Sh.

[0041] The heat pump device 1 is an indoor unit installed in a room such as a detached house, apartment building, or office building. The heat pump device 1 mainly comprises a refrigerant circuit 11, an electric heater EH, a switching valve Vt, and a control unit 15. The heat pump device 1 may also include, for example, a heat source pipeline 12, a utilization pipeline 13, a control valve 14, a utilization pump 16, a branch pipeline 17, a hot water storage tank HWT, a heat exchange coil HC, a water supply pipeline 18, and a hot water supply pipeline 19.

[0042] The refrigerant circuit 11 includes a compressor 111, a first heat exchanger 112, a pressure reducing mechanism 113, a second heat exchanger 114, and a switching mechanism 116, and performs a refrigeration cycle. The refrigerant circuit 11 also includes, for example, a refrigerant line 115 and a check valve 117.

[0043] The compressor 111 is installed in the refrigerant pipeline 115 and compresses the refrigerant Fr filled in the refrigerant pipeline 115. The compressor 111 can be appropriately selected according to the application and capacity, for example, from a swing compressor, scroll compressor, screw compressor, turbo compressor, etc. The compressor 111 includes, for example, a motor housed in a casing to drive the compression mechanism and an inverter to control the power supplied to the motor.

[0044] The first heat exchanger 112 is connected, for example, to the refrigerant line 115 of the refrigerant circuit 11 and to the heat source line 12 of the heat pump device 1 which constitutes part of the heat source circuit 2, and exchanges heat between the refrigerant Fr flowing through the refrigerant line 115 and the heat source fluid Fh flowing through the heat source line 12. The method of heat exchange in the first heat exchanger 112 is not particularly limited.

[0045] The pressure reducing mechanism 113 reduces the pressure of the refrigerant Fr flowing through the refrigerant pipeline 115. The pressure reducing mechanism 113 is, for example, an expansion valve provided in the refrigerant pipeline 115 connecting the first heat exchanger 112 and the second heat exchanger 114. The pressure reducing mechanism 113 is, for example, a control valve whose opening degree can be changed under the control of the control unit 15.

[0046] The second heat exchanger 114 is connected, for example, to the refrigerant line 115 of the refrigerant circuit 11 and the utilization line 13 of the heat pump device 1 which constitutes part of the utilization circuit 3, and exchanges heat between the refrigerant Fr flowing through the refrigerant line 115 and the utilization fluid Fu flowing through the utilization line 13. The method of heat exchange in the second heat exchanger 114 is not particularly limited.

[0047] The refrigerant pipeline 115 is composed of piping that circulates the refrigerant Fr in the refrigerant circuit 11. The refrigerant pipeline 115 may include, for example, piping that passes through the inside of the first heat exchanger 112, or piping that passes through the inside of the second heat exchanger 114. The refrigerant pipeline 115 is provided with pressure detection devices PI on the discharge side and suction side of the compressor 111, respectively. The pressure detection devices PI detect the pressure of the refrigerant Fr on the discharge side and suction side of the compressor 111 and output the detection result to the control unit 15.

[0048] Furthermore, the refrigerant pipeline 115 is equipped with, for example, a third temperature detection device TI3 on ​​both the inlet and outlet sides of the refrigerant Fr in the first heat exchanger 112. The third temperature detection device TI3 detects the inlet temperature and outlet temperature of the refrigerant Fr in the inlet and outlet sides of the refrigerant Fr in the first heat exchanger 112, respectively, and outputs the detection results to the control unit 15.

[0049] Furthermore, the refrigerant pipeline 115 is equipped with, for example, a fourth temperature detection device TI4 on both the inlet and outlet sides of the refrigerant Fr in the second heat exchanger 114. The fourth temperature detection device TI4 detects the inlet and outlet temperatures of the refrigerant Fr in the second heat exchanger 114, respectively, and outputs the detection results to the control unit 15.

[0050] The switching mechanism 116 is configured to switch between cooling operation, in which the second heat exchanger 114 functions as an evaporator, and heating operation, in which the second heat exchanger 114 functions as a heat radiator, by switching the flow direction of the refrigerant Fr. Specifically, the switching mechanism 116 is, for example, a four-way switching valve connected to the first heat exchanger 112 and the second heat exchanger 114 via refrigerant lines 115, and also connected to the discharge port and suction port of the compressor 111 via refrigerant lines 115. The switching mechanism 116 switches between cooling operation and heating operation of the refrigerant circuit 11 by switching the flow path, for example, controlled by the control unit 15.

[0051] During cooling operation, the refrigerant circuit 11 uses the second heat exchanger 114 as an evaporator for the refrigerant Fr to cool the working fluid Fu. At this time, the switching mechanism 116 switches the flow path so that the refrigerant Fr flowing out of the second heat exchanger 114 is introduced into the suction port of the compressor 111, and the refrigerant Fr discharged from the compressor 111 is introduced into the first heat exchanger 112, as shown by the dashed line.

[0052] During heating operation, the refrigerant circuit 11 uses the second heat exchanger 114 as a heat radiator for the refrigerant Fr to heat the working fluid Fu. At this time, the switching mechanism 116 switches the flow path so that the refrigerant Fr flowing out of the first heat exchanger 112 is introduced into the suction port of the compressor 111, and the refrigerant Fr discharged from the compressor 111 is introduced into the second heat exchanger 114, as shown by the solid line.

[0053] The check valve 117 is installed in the refrigerant pipeline 115 that connects the discharge port of the compressor 111 and the switching mechanism 116. The check valve 117 allows the refrigerant Fr flowing from the compressor 111 to the switching mechanism 116 to pass through, and blocks the reverse flow of refrigerant Fr from the switching mechanism 116 to the compressor 111.

[0054] The heat source conduit 12 of the heat pump device 1 passes the heat source fluid Fh circulating in the heat source circuit 2 to the first heat exchanger 112. The heat source conduit 12 includes a supply pipe connecting the supply heat source conduit 24 of the heat source circuit 2 to the inlet of the heat source fluid Fh in the first heat exchanger 112. The heat source conduit 12 also includes a return pipe connecting the outlet of the heat source fluid Fh in the first heat exchanger 112 to the return heat source conduit 25 of the heat source circuit 2. The heat source conduit 12 may also include a pipe passing through the inside of the first heat exchanger 112. The heat source conduit 12 constitutes a part of the heat source circuit 2 that circulates the heat source fluid Fh.

[0055] Furthermore, the heat source pipeline 12 is equipped with first temperature detection devices TI1 on both the inlet and outlet sides of the heat source fluid Fh of the first heat exchanger 112. The first temperature detection devices TI1 measure the inlet and outlet temperatures of the heat source fluid Fh at the inlet and outlet sides of the first heat exchanger 112 and output the measurement results to the control unit 15. The first temperature detection devices TI1 are provided in the supply and return piping of the heat source pipeline 12. In addition, the heat source pipeline 12 is equipped with a control valve 14.

[0056] The control valve 14 is installed, for example, in the supply piping of the heat source pipeline 12. The control valve 14 includes a differential pressure adjustment mechanism that uses the differential pressure of the heat source fluid Fh to maintain the flow rate of the heat source fluid Fh within a certain range relative to a predetermined pressure range. The control valve 14 is also referred to as a pressure independent control valve (PICV), a pressure regulating valve, or a constant flow valve. The control valve 14 is connected to the control unit 15 via a wired or wireless communication line and is controlled by the control unit 15.

[0057] The utilization line 13 of the heat pump device 1 is connected to the utilization line 32 of the utilization circuit 3 and constitutes a part of the utilization circuit 3. The utilization line 13 passes the utilization fluid Fu circulating in the utilization circuit 3 to the second heat exchanger 114 of the refrigerant circuit 11. That is, the utilization circuit 3 may include the utilization line 13 of the heat pump device 1 and the second heat exchanger 114.

[0058] The utilization pipeline 13 includes a supply pipe connecting the outlet of the utilization fluid Fu of the second heat exchanger 114 to the supply pipe of the utilization pipeline 32 that constitutes the utilization circuit 3. The utilization pipeline 13 also includes a return pipe connecting the return pipe of the utilization pipeline 32 that constitutes the utilization circuit 3 to the inlet of the second heat exchanger 114. Furthermore, the utilization pipeline 13 may include a pipe that passes through the inside of the second heat exchanger 114.

[0059] The supply piping of utilization pipeline 13 supplies the utilization fluid Fu from the second heat exchanger 114 to each utilization section 31 via the supply piping of utilization pipeline 32. The return piping of utilization pipeline 13 recirculates the utilization fluid Fu from each utilization section 31 to the second heat exchanger 114 via the return piping of utilization pipeline 32. The piping of utilization pipeline 13 that passes inside the second heat exchanger 114 allows the utilization fluid Fu to pass through the inside of the second heat exchanger 114, and heat exchange occurs between the utilization fluid Fu and the refrigerant Fr of the refrigerant circuit 11.

[0060] The utilization pipeline 13 includes a second temperature detection device TI2 that detects the inlet and outlet temperatures of the utilization fluid Fu at the inlet and outlet sides of the utilization fluid Fu of the second heat exchanger 114. The second temperature detection device TI2 is provided in the supply and return piping of the utilization pipeline 13, respectively. In addition, the supply piping of the utilization pipeline 13 is provided with an on-off valve and a switching valve Vt running from the upstream side to the downstream side of the utilization fluid Fu flow, and the return piping of the utilization pipeline 13 is provided with an on-off valve and a utilization pump 16 running from the upstream side to the downstream side of the utilization fluid Fu flow.

[0061] The utilization pump 16 pumps the utilization fluid Fu and circulates it through the utilization circuit 3, which includes the utilization pipeline 13 and the second heat exchanger 114 of the heat pump device 1. The utilization pump 16 is connected to the control unit 15, for example, via a wired or wireless communication line, and the discharge rate is controlled by the control unit 15.

[0062] The switching valve Vt is installed in the supply piping of the utilization pipeline 13 and connected to the branch pipeline 17. The switching valve Vt is a three-way valve having, for example, a first opening connected to the second heat exchanger 114 via the utilization pipeline 13, a second opening connected to the utilization pipeline 32 of the utilization circuit 3 via the utilization pipeline 13, and a third opening connected to the branch pipeline 17. The switching valve Vt may also be composed of a plurality of control valves.

[0063] Furthermore, the switching valve Vt has a valve body that can switch between a first state and a second state, and a drive unit that drives the valve body to switch between the first state and the second state. The drive unit is connected to the control unit 15, for example, via a wired or wireless communication line, and is controlled by the control unit 15 to switch between the first state and the second state of the switching valve Vt.

[0064] The first state of the switching valve Vt is one in which the valve body connects the first and second openings, connecting the upstream and downstream sides of the utilization pipeline 13 in the flow direction of the utilization fluid Fu, and blocks the connection between the upstream side of the utilization pipeline 13 and the branch pipeline 17 by blocking the connection between the first and third openings. In this first state, the utilization fluid Fu that flows from the second heat exchanger 114 to the first opening of the switching valve Vt via the utilization pipeline 13 passes through the switching valve Vt and flows into the utilization pipeline 32 of the utilization circuit 3 via the utilization pipeline 13 connected to the second opening of the switching valve Vt.

[0065] The second state of the switching valve Vt is a state in which the valve body blocks the connection between the first and second openings, thereby blocking the connection between the upstream and downstream sides of the utilization pipeline 13 in the flow direction of the utilization fluid Fu, and connects the first and third openings, thereby connecting the upstream side of the utilization pipeline 13 to the branch pipeline 17. In this second state, the utilization fluid Fu that flows from the second heat exchanger 114 through the utilization pipeline 13 to the first opening of the switching valve Vt passes through the switching valve Vt and flows into the branch pipeline 17 connected to the third opening of the switching valve Vt.

[0066] The branch pipeline 17 has an upstream pipe connecting the third opening of the switching valve Vt to the inlet of the heat exchange coil HC housed in the hot water storage tank HWT, and a downstream pipe connecting the outlet of the heat exchange coil HC to the utilization pipeline 13. When the switching valve Vt is switched to the second state, the branch pipeline 17 allows the utilization fluid Fu to pass through the heat exchange coil HC. The utilization section 31 of the utilization circuit 3 may include, for example, the heat exchange coil HC.

[0067] The hot water storage tank HWT houses a heat exchange coil HC inside. The hot water storage tank HWT is connected to a water supply pipe 18 and a hot water supply pipe 19. The utilization circuit 3 also includes, for example, a water supply pipe 33 and a hot water supply pipe 34. The water supply pipe 33 and the hot water supply pipe 34 of the utilization circuit 3 are connected to the water supply pipe 18 and the hot water supply pipe 19 of the heat pump device 1 at ends where on-off valves are provided. The hot water storage tank HWT may be located outside the heat pump device 1.

[0068] The water supply pipeline 33 of the utilization circuit 3 supplies tap water TW to the hot water storage tank HWT via the water supply pipeline 18 of the heat pump device 1. The hot water storage tank HWT stores the tap water TW supplied via the water supply pipeline 18. The tap water TW stored in the hot water storage tank HWT is heated by heat exchange with the utilization fluid Fu flowing through the heat exchange coil HC to become hot water HW. The hot water HW in the hot water storage tank HWT is supplied to equipment that uses hot water HW, such as showers Sh, via the hot water supply pipeline 19 of the heat pump device 1 and the hot water supply pipeline 34 of the utilization circuit 3.

[0069] The electric heater EH of the heat pump device 1 is located inside the hot water storage tank HWT, which houses the heat exchange coil HC. As mentioned above, the heat exchange coil HC is installed in a branch pipe 17 that branches off from the utilization pipe 13 that passes the utilization fluid Fu to the second heat exchanger 114. As will be described in detail later, the electric heater EH can heat the tap water TW in the hot water storage tank HWT by energizing it, even when the refrigerant circuit 11 is in cooling operation and cannot heat the tap water TW in the hot water storage tank HWT by the heat exchange coil HC.

[0070] The control unit 15 includes, for example, an electronic circuit such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit), a memory such as ROM (Read Only Memory) or RAM (Random Access Memory), and an input / output unit. The control unit 15 performs various control operations by executing a program stored in memory using the CPU or by designing the circuit for special applications.

[0071] The control unit 15 is connected to various parts of the heat pump device 1 via an input / output unit and a wired or wireless communication line. Specifically, the control unit 15 is connected to, for example, the compressor 111, the pressure reducing mechanism 113, the switching mechanism 116, the control valve 14, the utilization pump 16, the first temperature detection device TI1, the second temperature detection device TI2, the third temperature detection device TI3, the fourth temperature detection device TI4, the pressure detection device PI, the electric heater EH, etc.

[0072] The control unit 15 controls the rotational speed and capacity of the compressor 111, for example, by controlling the inverter that supplies power to the motor of the compressor 111. The control unit 15 also controls the pressure reducing mechanism 113, for example, to change the opening degree of the pressure reducing mechanism 113. The control unit 15 also controls the switching mechanism 116, for example, to switch between cooling operation and heating operation of the refrigerant circuit 11. The control unit 15 also controls the discharge amount of the utilization pump 16, for example, according to an indicator related to the load of the utilization circuit 3. The control unit 15 also controls the switching valve Vt, for example, to switch between the first state and the second state of the switching valve Vt. The control unit 15 also controls the electric heater EH, for example, to switch between a state in which the electric heater EH is energized and a state in which the electric heater EH is not energized.

[0073] Next, with reference to Figure 2, the arrangement of the electric heater EH housed in the hot water storage tank HWT will be described. Figure 2 is a circuit diagram showing an enlarged view of the area around the hot water storage tank HWT in the circuit diagram of Figure 1.

[0074] If the refrigerant Fr filled into the refrigerant circuit 11 is a flammable gas with a specific gravity greater than air at atmospheric pressure, the electrical connection part EC of the electric heater EH is located, for example, above the hot water storage tank HWT. Examples of flammable refrigerants Fr with a specific gravity greater than air at atmospheric pressure include R454C, R32, R1234yf, and R290 (propane).

[0075] Specifically, in the example shown in Figure 2, the electric heater EH has a rod-shaped heating element with an electrical connection part EC at one end. The rod-shaped heating element of the electric heater EH is inserted into the hot water storage tank HWT through an opening at the upper end of the hot water storage tank HWT and extends to the bottom of the hot water storage tank HWT. The electrical connection part EC of the electric heater EH is located above the opening at the upper end of the hot water storage tank HWT. When energized, only the lower part of the rod-shaped heating element of the electric heater EH may generate heat, the entire element may generate heat, or the lower and upper parts may be configured to generate heat selectively.

[0076] Furthermore, the electric heater EH may be located in the upper half UH of the hot water storage tank HWT. Here, the portion of the hot water storage tank HWT above the center in the height direction is referred to as the upper half UH of the hot water storage tank HWT, and the portion of the hot water storage tank HWT below the center in the height direction is referred to as the lower half LH of the hot water storage tank HWT.

[0077] Specifically, the electric heater EH may, for example, have a rod-shaped heating element inserted into an opening at the upper end of the hot water storage tank HWT, as shown by the dashed line in Figure 2, and extending vertically within the upper half UH of the hot water storage tank HWT to a position slightly above the lower half LH. Alternatively, the electric heater EH may, for example, have a rod-shaped heating element inserted into an opening in the side wall of the hot water storage tank HWT, as shown by the dashed line in Figure 2, and extending horizontally within the upper half UH of the hot water storage tank HWT.

[0078] Furthermore, the electric heater EH may be located in the lower half LH of the hot water storage tank HWT. Specifically, the electric heater EH may have a rod-shaped heating element inserted into an opening in the side wall of the hot water storage tank HWT, as shown by the dashed line in Figure 2, and extending horizontally inside the lower half LH of the hot water storage tank HWT. Also, the electric heater EH may have an upper heater UEH located in the upper half UH of the hot water storage tank HWT and a lower heater LEH located in the lower half LH of the hot water storage tank HWT, as shown by the dashed line in Figure 2.

[0079] Furthermore, the heat pump device 1 may be equipped with a water temperature sensor TI5 that detects the temperature of the hot water HW stored in the hot water storage tank HWT. The water temperature sensor TI5 is connected to the control unit 15, for example, via a wired or wireless communication line, and transmits the detection result of the water temperature stored in the hot water storage tank HWT to the control unit 15. The temperature detection unit of the water temperature sensor TI5 is located, for example, in the upper half UH of the hot water storage tank HWT and detects the temperature of the water stored in the upper half UH of the hot water storage tank HWT.

[0080] Next, referring to Figures 3 and 4, the processes performed by the control unit 15 of the heat pump device 1 will be described. Figure 3 is a flowchart illustrating an example of the processing flow of the control unit 15 that constitutes the heat pump device 1 shown in Figure 1.

[0081] When the control unit 15 starts the processing flow shown in Figure 3, it executes a process P1 to acquire the operating state of the refrigerant circuit 11, for example. The operating state of the refrigerant circuit 11 includes cooling operation and heating operation. The operating state of the refrigerant circuit 11 also includes hot water storage operation. Hot water storage operation is an operating state in which hot water HW is generated by heating the water in the hot water storage tank HWT using, for example, an electric heater EH or a heat exchange coil HC. Specifically, in hot water storage operation during cooling operation of the refrigerant circuit 11, the electric heater EH is energized, and the water in the hot water storage tank HWT is heated by the electric heater EH to generate hot water HW. In addition, in hot water storage operation during heating operation of the refrigerant circuit 11, the switching valve Vt is switched to the second state to allow the working fluid Fu to pass through the heat exchange coil HC, and the water in the hot water storage tank HWT is heated by heat exchange between the working fluid Fu and the water in the hot water storage tank HWT to generate hot water HW. Note that the electric heater EH may also be energized during hot water storage operation during heating operation. The hot water storage operation can also be called the hot water heating operation. During the hot water storage operation, hot water may or may not be supplied from the hot water storage tank (HWT) to the hot water utilization equipment.

[0082] In this process P1, the control unit 15 acquires the operating state of the refrigerant circuit 11, which is set, for example, by the user operating the remote controller or control panel of the heat pump device 1. In this process P1, the control unit 15 may also acquire, for example, the set temperature set in the utilization unit 31 of the utilization circuit 3 and the temperature of the room in which the utilization unit 31 is installed, and determine the operating state.

[0083] Next, the control unit 15 executes process P2 to control the controlled object according to the operating state acquired in process P1. Here, the controlled object of the control unit 15 includes, for example, the refrigerant circuit 11, control valve 14, switching valve Vt, and utilization pump 16 of the heat pump device 1 shown in Figure 1. In addition, the controlled object of the control unit 15 in the refrigerant circuit 11 includes the compressor 111, pressure reducing mechanism 113, and switching mechanism 116.

[0084] Next, the control unit 15 executes a process P3 to acquire the temperature of the hot water HW stored in the hot water storage tank HWT. In this process P3, the control unit 15 acquires the temperature of the hot water HW in the hot water storage tank HWT, for example, detected by the water temperature sensor TI5 shown in Figure 2.

[0085] Next, the control unit 15 executes a process P4 to determine whether the operating state of the refrigerant circuit 11 is cooling operation and whether there is insufficient hot water HW in the hot water storage tank HWT. In this process P4, the control unit 15 determines affirmative (YES) if, for example, the operating state obtained in the aforementioned process P1 is cooling operation and the temperature of the hot water HW obtained in the previous process P3 is below a predetermined temperature. In this case, the control unit 15 executes a process P5 to run the first mode.

[0086] In this process P5, the control unit 15 controls the switching mechanism 116 shown in Figure 1 to perform cooling operation, and at the same time controls the switching valve Vt to the first state, energizing the electric heater EH to heat the water stored in the hot water storage tank HWT, executing a first mode. As a result, during the cooling operation of the refrigerant circuit 11, which uses the second heat exchanger 114 shown in Figure 1 as an evaporator, the switching valve Vt blocks the connection between the utilization pipe 13 and the branch pipe 17.

[0087] Furthermore, the utilization fluid Fu, cooled by heat exchange with the refrigerant Fr in the second heat exchanger 114, is supplied to the utilization section 31 of the utilization circuit 3 through the utilization pipeline 13 and the switching valve Vt. Also, during the cooling operation of the refrigerant circuit 11, that is, simultaneously with the cooling operation of the refrigerant circuit 11, a hot water storage operation is performed in which tap water TW in the hot water storage tank HWT is heated by the energization of the electric heater EH to generate hot water HW. After that, the control unit 15 terminates the processing flow shown in Figure 3 and repeats it at a predetermined cycle.

[0088] On the other hand, in the aforementioned process P4, the control unit 15 determines negation (NO) if, for example, the operating state obtained in the aforementioned process P1 is heating operation, or if the temperature of the hot water HW obtained in the previous process P3 exceeds a predetermined temperature. In this case, the control unit 15 executes a process P6 to determine, for example, whether the operating state of the refrigerant circuit 11 is heating operation and whether there is a shortage of hot water.

[0089] In this process P6, the control unit 15 determines affirmative (YES) if the operating state obtained in the aforementioned process P1 is heating operation and the temperature of the hot water HW obtained in the aforementioned process P3 is below a predetermined temperature. In this case, the control unit 15 performs process P7 to execute the second mode.

[0090] In this process P7, the control unit 15 controls the switching mechanism 116 shown in Figure 1 to perform heating operation, and at the same time controls the switching valve Vt to the second state, executing a second mode in which the utilization fluid Fu passes through the heat exchange coil HC to heat the water stored in the hot water storage tank HWT.

[0091] As a result, during heating operation in which the second heat exchanger 114 shown in Figure 1 functions as a heat radiator, the utilization fluid Fu, whose temperature has risen due to heat exchange with the refrigerant Fr in the second heat exchanger 114, passes through the heat exchange coil HC via the utilization pipe 13, the switching valve Vt, and the branch pipe 17. Consequently, a hot water storage operation is performed in which heat exchange takes place between the utilization fluid Fu passing through the heat exchange coil HC and the tap water TW stored in the hot water storage tank HWT, generating hot water HW.

[0092] Subsequently, the control unit 15 terminates the processing flow shown in Figure 3 and repeats it at a predetermined cycle. In addition, in the aforementioned process P6, the control unit 15 determines negation (NO) if the operating state obtained in the aforementioned process P1 is cooling operation, or if the temperature of the hot water HW obtained in the aforementioned process P3 exceeds a predetermined temperature. In this case as well, the control unit 15 terminates the processing flow shown in Figure 3 and repeats it at a predetermined cycle.

[0093] Figure 4 is a flowchart showing the details of process P5, which executes the first mode in Figure 3.

[0094] The control unit 15 switches between cooling-priority operation and hot water-priority operation, for example, in the first mode. In cooling-priority operation, the power available in the heat pump device 1 is supplied to the compressor 111 according to the load of the refrigeration cycle of the refrigerant circuit 11, and the surplus power is supplied to the electric heater EH. In hot water-priority operation, the power available in the heat pump device 1 is supplied to the electric heater EH for heating the water stored in the hot water storage tank HWT, and the surplus power is supplied to the compressor 111.

[0095] Specifically, the control unit 15, for example, executes process P5 in Figure 3 to start a first mode in which the switching valve Vt is set to a first state and the electric heater EH is energized during the cooling operation of the refrigerant circuit 11, and then starts the processing flow shown in Figure 4. First, the control unit 15 executes process P51 to determine whether the temperature of the hot water HW is below a predetermined temperature.

[0096] In this process P51, if the control unit 15 determines, for example, that the temperature of the hot water HW obtained in the aforementioned process P3 is below a predetermined temperature (YES), it performs process P52 to execute hot water priority operation. In this process P52, the control unit 15 performs hot water priority operation by supplying the electric heater EH with the power necessary to heat the water, such as tap water TW or hot water HW, stored in the hot water storage tank HWT, from the power available in the first mode, and supplying the surplus power to the compressor 111.

[0097] On the other hand, in the aforementioned process P51, if the control unit 15 determines, for example, that the temperature of the hot water HW obtained in the aforementioned process P3 exceeds a predetermined temperature (NO), it performs process P53 to determine whether the load index of the utilization circuit 3 is above a predetermined value.

[0098] Here, the load of utilization circuit 3 can be rephrased as, for example, the air conditioning load of utilization unit 31, the refrigeration cycle load of refrigerant circuit 11, or the load of the second heat exchanger 114 in refrigerant circuit 11. The indicators of the load of utilization circuit 3 include, for example, one or more of the following: the rotational speed of compressor 111, the temperature difference between the inlet and outlet temperatures of utilization fluid Fu, or the temperature difference between the inlet and outlet temperatures of heat source fluid Fh.

[0099] In process P53, if the control unit 15 determines, for example, that the load indicator of the utilization circuit 3 is above a predetermined value (YES), it performs process P54 to execute cooling priority operation. In this process P54, the control unit 15 performs cooling priority operation by supplying power to the compressor 111 according to the load of the refrigeration cycle from the power available in the first mode, and supplying the surplus power to the electric heater EH.

[0100] Thus, the control unit 15, for example, executes hot water priority operation in process P52 when the temperature of the hot water HW detected by the water temperature sensor TI5 shown in Figure 2 is below a predetermined temperature. In addition, the control unit 15 executes cooling priority operation in process P54 when the load indicator of the utilization circuit 3 connected to the utilization pipeline 13 shown in Figure 1 is above a predetermined value.

[0101] If cooling priority operation is performed in process P54, the control unit 15 terminates process P5 shown in Figure 4 and the process flow shown in Figure 3, and repeats the process flow shown in Figure 3 at a predetermined cycle. Also, in the aforementioned process P53, the control unit 15 determines negation (NO) if the indicator related to the load of the utilization circuit 3 is less than a predetermined value. In this case as well, the control unit 15 terminates process P5 shown in Figure 4 and the process flow shown in Figure 3, and repeats the process flow shown in Figure 3 at a predetermined cycle.

[0102] Furthermore, as shown in Figure 4, the control unit 15 may, for example, execute a process P55 to determine whether or not the electric heater EH is malfunctioning after the process P52 which executes hot water priority operation. In this process P55, the control unit 15 determines that the electric heater EH is malfunctioning, for example, if the rate of change of the water temperature in the hot water storage tank HWT detected by the water temperature sensor TI5 is below a predetermined value, or if there is an abnormality in the power supply to the electric heater EH.

[0103] In this process P55, if the control unit 15 determines that the electric heater EH is not malfunctioning (NO), it terminates process P5 shown in Figure 4 and the process flow shown in Figure 3, and repeats the process flow shown in Figure 3 at a predetermined interval. On the other hand, in the aforementioned process P55, if the control unit 15 determines that the electric heater EH is malfunctioning (YES), it performs process P56, which executes the second mode periodically.

[0104] In this process P56, the control unit 15 controls the switching mechanism 116 to switch the refrigerant circuit 11 from cooling operation to heating operation, and periodically executes a second mode in which the switching valve Vt is controlled to a second state to allow the utilization fluid Fu to pass through the heat exchange coil HC. After that, the control unit 15 terminates the process P5 shown in Figure 4 and the process flow shown in Figure 3, and repeats the process flow shown in Figure 3 at a predetermined cycle.

[0105] The operation of the heat pump device 1 of this embodiment will be described below.

[0106] As described above, the heat pump device 1 of this embodiment includes a refrigerant circuit 11, an electric heater EH, a switching valve Vt, and a control unit 15. The refrigerant circuit 11 includes a compressor 111, a first heat exchanger 112, a pressure reducing mechanism 113, a second heat exchanger 114, and a switching mechanism 116, and performs a refrigeration cycle. The compressor 111 compresses the refrigerant Fr. The first heat exchanger 112 exchanges heat between the refrigerant Fr and the heat source fluid Fh. The pressure reducing mechanism 113 reduces the pressure of the refrigerant Fr. The second heat exchanger 114 exchanges heat between the refrigerant Fr and the utilization fluid Fu. The switching mechanism 116 is configured to switch between cooling operation, in which the second heat exchanger 114 functions as an evaporator, and heating operation, in which the second heat exchanger 114 functions as a heat radiator, by switching the flow direction of the refrigerant Fr. The electric heater EH is located inside the hot water storage tank HWT. The hot water storage tank HWT houses a heat exchange coil HC located in a branch pipeline 17 that branches off from the utilization pipeline 13 through which the utilization fluid Fu passes to the second heat exchanger 114. A switching valve Vt is provided in the utilization pipeline 13 and is configured to switch between a first state, which connects the upstream and downstream sides of the utilization pipeline 13, and a second state, which connects the upstream side of the utilization pipeline 13 to the branch pipeline 17. The control unit 15 controls the switching mechanism 116 to perform cooling operation and simultaneously controls the switching valve Vt to the first state, energizing the electric heater EH to heat the water stored in the hot water storage tank HWT, executing a first mode.

[0107] With this configuration, the heat pump device 1 can switch between cooling operation, in which the second heat exchanger 114 functions as an evaporator, and heating operation, in which the second heat exchanger 114 functions as a heat radiator, by controlling the switching mechanism 116 via the control unit 15. Furthermore, the heat pump device 1 can switch between a first state, in which the upstream and downstream sides of the utilization pipeline 13 are connected, and a second state, in which the upstream side of the utilization pipeline 13 is connected to the branch pipeline 17, by controlling the switching valve Vt via the control unit 15. As a result, the control unit 15 can control the switching mechanism 116 to perform cooling operation and, at the same time, control the switching valve Vt to the first state to energize the electric heater EH and execute a first mode, which heats the water stored in the hot water storage tank HWT. Therefore, according to this embodiment, it is possible to provide a heat pump device 1 that can simultaneously perform cooling operation and hot water storage operation, in which the water stored in the hot water storage tank HWT is heated.

[0108] Furthermore, in the heat pump device 1 of this embodiment, the control unit 15 controls the switching mechanism 116 to perform heating operation. Simultaneously with this heating operation, the control unit 15 controls the switching valve Vt to a second state and executes a second mode in which the utilization fluid Fu passes through the heat exchange coil HC to heat the water stored in the hot water storage tank HWT.

[0109] With this configuration, during the heating operation of the heat pump device 1, the working fluid Fu, whose temperature has risen due to heat exchange with the refrigerant Fr, is passed through the heat exchange coil HC, and water such as tap water TW or low-temperature hot water HW stored in the hot water storage tank HWT can be heated by heat exchange with the working fluid Fu. Therefore, during the heating operation of the heat pump device 1, hot water storage operation can be performed without energizing the electric heater EH, thereby reducing the power consumption of hot water storage operation.

[0110] Furthermore, in the heat pump device 1 of this embodiment, the control unit 15, in the first mode, performs cooling-priority operation by supplying power to the compressor 111 according to the load of the refrigeration cycle from the available power, and supplying surplus power to the electric heater EH.

[0111] With this configuration, in the first mode in which the heat pump device 1 performs both cooling and hot water storage operations simultaneously, available power can be preferentially supplied to the compressor 111 of the refrigerant circuit 11. This allows for cooling operations that correspond to the load of the refrigeration cycle of the refrigerant circuit 11, such as the cooling load from air conditioning equipment like a radiator 311 using the working fluid Fu. Furthermore, by supplying surplus power to the electric heater EH, cooling and hot water storage operations can be performed simultaneously without reducing the cooling capacity of the heat pump device 1.

[0112] Furthermore, in the heat pump device 1 of this embodiment, the electric heater EH is positioned in the upper half UH of the hot water storage tank HWT.

[0113] With this configuration, the water stored in the upper half UH of the hot water storage tank HWT can be preferentially heated by the electric heater EH located in the upper half UH of the hot water storage tank HWT. As a result, the temperature of the water stored in the upper half UH can be raised with less power compared to heating the water stored in the entire hot water storage tank HWT. Therefore, even when cooling-priority operation is performed in the first mode in which the heat pump device 1 performs cooling operation and hot water storage operation simultaneously, hot water HW at the desired temperature can be supplied from the upper half UH of the hot water storage tank HWT.

[0114] Furthermore, in the heat pump device 1 of this embodiment, the control unit 15, in the first mode, performs hot water priority operation by supplying the electric heater EH with the power necessary to heat the water stored in the hot water storage tank HWT from the available power, and supplying the surplus power to the compressor 111.

[0115] With this configuration, in the first mode in which the heat pump device 1 performs both cooling and hot water storage operations simultaneously, available power can be preferentially supplied to the electric heater EH. This allows hot water HW at the required temperature to be generated in the hot water storage tank HWT in a short time. Furthermore, by supplying surplus power to the compressor 111 of the refrigerant circuit 11, cooling and hot water storage operations can be performed simultaneously without reducing the hot water generation capacity of the electric heater EH.

[0116] Furthermore, in the heat pump device 1 of this embodiment, the control unit 15 switches between cooling-priority operation and hot water-priority operation in the first mode. In cooling-priority operation, the control unit 15 supplies power to the compressor 111 according to the load of the refrigeration cycle from the available power, and supplies the surplus power to the electric heater EH. In hot water-priority operation, the control unit 15 supplies power to the electric heater EH necessary for heating the water stored in the hot water storage tank HWT from the available power, and supplies the surplus power to the compressor 111.

[0117] This configuration allows the heat pump unit 1 to switch between cooling-priority operation and hot water-priority operation depending on the situation. As a result, in the first mode, cooling operation and hot water storage operation can be performed simultaneously without reducing the hot water generation capacity of the electric heater EH, or cooling operation and hot water storage operation can be performed simultaneously without reducing the cooling capacity of the heat pump unit 1.

[0118] Furthermore, the heat pump device 1 of this embodiment is further equipped with a water temperature sensor TI5 that detects the temperature of the hot water HW stored in the hot water storage tank HWT. The control unit 15 performs hot water priority operation when the temperature of the hot water HW detected by the water temperature sensor TI5 is below a predetermined temperature.

[0119] With this configuration, if the temperature of the hot water HW detected by the water temperature sensor TI5 falls below a predetermined temperature and there is insufficient hot water HW stored in the hot water storage tank HWT, the system can perform a hot water priority operation to quickly generate hot water HW.

[0120] Furthermore, in the heat pump device 1 of this embodiment, the control unit 15 performs cooling priority operation when the indicator related to the load of the utilization circuit 3 connected to the utilization pipeline 13 is equal to or greater than a predetermined value.

[0121] With this configuration, for example, if the cooling load from the air conditioning equipment using the utilization fluid Fu increases and the indicator for the load of the utilization circuit 3 connected to the utilization pipeline 13 exceeds a predetermined value, cooling priority operation can be performed to supply power to the compressor 111 of the refrigerant circuit 11 according to the load of the utilization circuit 3. As a result, the heat pump device 1 can exert a cooling capacity corresponding to the cooling load of the utilization circuit 3.

[0122] Furthermore, in the heat pump device 1 of this embodiment, the control unit 15 periodically executes the second mode when the electric heater EH fails.

[0123] With this configuration, the control unit 15 can periodically execute the second mode during cooling operation even when the electric heater EH fails. This allows the control unit 15 to periodically perform heating operation between cooling operations of the refrigerant circuit 11, allowing the working fluid Fu to pass through the heat exchange coil HC. As a result, in the heat pump device 1, during heating operation between cooling operations, the working fluid Fu, whose temperature has risen due to heat exchange with the refrigerant Fr in the second heat exchanger 114, is periodically heat-exchanged with the hot water HW stored in the hot water storage tank HWT, thereby suppressing the temperature drop of the hot water HW.

[0124] Furthermore, in the heat pump device 1 of this embodiment, the electric heater EH is located in the lower half LH of the hot water storage tank HWT.

[0125] With this configuration, the electric heater EH heats the water stored in the lower half LH of the hot water storage tank HWT, such as tap water TW or low-temperature hot water HW, thereby creating convection in the water stored in the hot water storage tank HWT. As a result, the water stored in the hot water storage tank HWT, including the lower half (LH) where low-temperature water tends to accumulate, can be heated overall to produce hot water HW.

[0126] Furthermore, in the heat pump device 1 of this embodiment, the electric heater EH includes an upper heater UEH located in the upper half UH of the hot water storage tank HWT, and a lower heater LEH located in the lower half LH of the hot water storage tank HWT.

[0127] This configuration allows the water stored in the upper half UH of the hot water storage tank HWT to be preferentially heated by the upper heater UEH. This allows the temperature of the water stored in the upper half UH to be raised with less power compared to heating the water stored in the hot water storage tank HWT as a whole. In addition, the water stored in the lower half LH of the hot water storage tank HWT can be heated by the lower heater LEH. This creates convection in the water stored in the hot water storage tank HWT, allowing the water stored in the hot water storage tank HWT to be heated as a whole to produce hot water HW.

[0128] Furthermore, in the heat pump device 1 of this embodiment, the refrigerant Fr is a flammable gas with a specific gravity greater than air at atmospheric pressure, and the electrical connection part EC of the electric heater EH is located above the hot water storage tank HWT.

[0129] This configuration improves the safety of the heat pump device 1 in the event of a leak of refrigerant Fr from the refrigerant circuit 11. Specifically, because refrigerant Fr has a higher specific gravity than air, it will accumulate below the heat pump device 1 if it leaks from the refrigerant circuit 11. Therefore, by placing the electrical connection part EC of the electric heater EH above the hot water storage tank HWT, contact between the electrical connection part EC of the electric heater EH and the flammable refrigerant Fr can be avoided.

[0130] As described above, this embodiment provides a heat pump device 1 that can simultaneously perform cooling operation and hot water storage operation, which heats the water in the hot water storage tank.

[0131] Preferred embodiments and variations of the present disclosure have been described in detail above. However, the present disclosure is not limited to the embodiments and variations described above. Various modifications or substitutions may be applied to the embodiments and variations described above without departing from the scope of the present disclosure. Furthermore, features described separately can be combined as long as no technical inconsistencies arise. [Explanation of Symbols]

[0132] 1. Heat pump system 11 Refrigerant Circuit 111 Compressor 112 1st heat exchanger 113 Pressure reduction mechanism 114 Second heat exchanger 116 Switching mechanism 13 Pipeline used 15 Control Unit 17 Branch pipeline 3 Circuit used EC connection section EH Electric Heater Fh heat source fluid Fr refrigerant Fu Fluid used HC heat exchange coil HWT Hot Water Storage Tank LEH lower heater LH lower half TI5 Water Temperature Sensor UH upper half UEH Top Heater Vt switching valve

Claims

1. A refrigerant circuit (11) that performs a refrigeration cycle includes a compressor (111) for compressing a refrigerant (Fr), a first heat exchanger (112) for exchanging heat between the refrigerant (Fr) and a heat source fluid (Fh), a pressure reducing mechanism (113) for reducing the pressure of the refrigerant (Fr), a second heat exchanger (114) for exchanging heat between the refrigerant (Fr) and a utilization fluid (Fu), and a switching mechanism (116) that can switch between a cooling operation in which the flow direction of the refrigerant (Fr) is switched so that the second heat exchanger (114) functions as an evaporator and a heating operation in which the second heat exchanger (114) functions as a heat radiator, An electric heater (EH) is placed inside a hot water storage tank (HWT) that houses a heat exchange coil (HC) provided in a branch pipe (17) that branches off from a utilization pipe (13) through which the utilization fluid (Fu) passes to the second heat exchanger (114), A switching valve (Vt) is provided in the utilization pipeline (13) and is capable of switching between a first state in which the upstream and downstream sides of the utilization pipeline (13) are connected, and a second state in which the upstream side of the utilization pipeline (13) is connected to the branch pipeline (17). The system includes a control unit (15) that controls the switching mechanism (116) to perform the cooling operation, and at the same time controls the switching valve (Vt) to the first state, energizes the electric heater (EH) to heat the water stored in the hot water storage tank (HWT), and executes a first mode. Heat pump device (1).

2. The control unit (15) controls the switching mechanism (116) to perform the heating operation, and at the same time controls the switching valve (Vt) to the second state, executing a second mode in which the utilization fluid (Fu) is passed through the heat exchange coil (HC) to heat the water stored in the hot water storage tank (HWT). The heat pump device (1) according to claim 1.

3. In the first mode, the control unit (15) performs cooling-priority operation by supplying power to the compressor (111) according to the load of the refrigeration cycle from the available power, and supplying the surplus power to the electric heater (EH). The heat pump device (1) according to claim 1.

4. The electric heater (EH) is positioned in the upper half (UH) of the hot water storage tank (HWT). The heat pump device (1) according to claim 3.

5. In the first mode, the control unit (15) performs a hot water priority operation, supplying the electric heater (EH) with the power necessary to heat the water stored in the hot water storage tank (HWT) from the available power, and supplying the surplus power to the compressor (111). The heat pump device (1) according to claim 1.

6. In the first mode, the control unit (15) In a cooling-priority operation, power corresponding to the load of the refrigeration cycle from the available power is supplied to the compressor (111), and surplus power is supplied to the electric heater (EH), The system switches between a hot water priority operation, which supplies the power necessary to heat the water stored in the hot water storage tank (HWT) to the electric heater (EH) and supplies the surplus power to the compressor (111), and a hot water priority operation. The heat pump device (1) according to claim 1.

7. The system further includes a water temperature sensor (TI5) for detecting the temperature of the hot water (HW) stored in the hot water storage tank (HWT), The control unit (15) executes the hot water priority operation when the temperature of the hot water (HW) detected by the water temperature sensor (TI5) is below a predetermined temperature. The heat pump device (1) according to claim 6.

8. The control unit (15) executes the cooling priority operation when the indicator related to the load of the utilization circuit (3) connected to the utilization pipeline (13) is equal to or greater than a predetermined value. The heat pump device (1) according to claim 6.

9. The control unit (15) periodically executes the second mode when the electric heater (EH) fails. The heat pump device (1) according to claim 2.

10. The electric heater (EH) is positioned in the lower half (LH) of the hot water storage tank (HWT). The heat pump device (1) according to claim 5.

11. The electric heater (EH) comprises an upper heater (UEH) positioned in the upper half (UH) of the hot water storage tank (HWT) and a lower heater (LEH) positioned in the lower half (LH) of the hot water storage tank (HWT). A heat pump device (1) according to claim 3 or claim 5.

12. The refrigerant (Fr) is a flammable gas that has a higher specific gravity than air at atmospheric pressure. The electrical connection point (EC) of the electric heater (EH) is located above the hot water storage tank (HWT). The heat pump device (1) according to claim 1.

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