JP2015190631A - Heat pump type hot water heater and method for controlling heat pump type hot water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump type hot water supply device capable of properly recovering hot water supply left in a high temperature side water pipe upon finishing of a boiling-up operation.SOLUTION: A water circulation pump 34 is stopped after completion of a boiling-up operation, and a circuit configuration of a water circulation circuit 30 is set such that the hot water supply flowed out of a water-refrigerant heat exchanger 12 is bypassed at a hot water storage tank and the water circulation pump 34 is operated until a change-over stop condition is established under a state in which it is changed over to a bypass passage side circulation circuit flowing water to a low temperature side water pipe 31 via the high temperature side water pipe 32 and the bypass water pipe 33. Further, when the changing-over stop condition is established, the water circulation pump 34 is operated until a water pressure feeding means stopping condition is established under a condition in which the circuit configuration of the water circulation circuit 30 is changed over to the tank side circulation circuit in which the hot water supply heated by the water-refrigerant heat exchanger 12 is flowed to the hot water storage tank 20 via the hot water side water pipe 32 in the same manner as that of the boiling-up operation.

Description

  The present invention relates to a heat pump type hot water heater that stores hot water heated in a heat pump cycle in a hot water storage tank, and a control method thereof.

  Conventionally, in Patent Literature 1, hot water (hot water) heated in a heat pump cycle is stored in a hot water storage tank, and tap water is mixed with the hot water stored in a hot water supply terminal disposed in a kitchen or a bathroom. A heat pump type hot water supply device for discharging hot water is disclosed. In the heat pump hot water heater of Patent Document 1, a boiling operation is performed in which hot water supplied in a hot water storage tank is heated using inexpensive commercial power (so-called late-night power) at night.

  Furthermore, in the heat pump type hot water heater of Patent Document 1, high temperature hot water remaining in the high temperature side water pipe is recovered in the hot water storage tank after the boiling operation is finished. Thereby, the energy loss by the heat | fever which the hot hot water which remains in the high temperature side water piping has is radiated | emitted in the atmosphere is suppressed. The high temperature side water pipe is a hot water supply pipe that guides hot water flowing out of the water-refrigerant heat exchanger to the hot water storage tank side.

  More specifically, the heat pump type water heater disclosed in Patent Document 1 includes temperature detection means (thermistor) that is disposed on the hot water inlet side of the hot water storage tank and detects the temperature of hot water flowing into the hot water storage tank. And even after the end of the boiling operation, the water circulation pump that pumps hot water to the water-refrigerant heat exchanger is operated until the hot water temperature detected by the thermistor is equal to or lower than a predetermined reference temperature. Hot hot water remaining in the high temperature side water piping is pumped into the hot water storage tank and recovered.

JP 2010-266135 A

  However, when the temperature detection means (thermistor) is arranged on the hot water supply inlet side of the hot water storage tank as in the heat pump hot water heater of Patent Document 1, the temperature of the hot hot water in the hot water storage tank is transferred to the thermistor. The temperature of hot water flowing through the high temperature side water pipe is likely to be erroneously detected at a value higher than the actual temperature. Therefore, there is a possibility that hot water remaining in the high-temperature side water pipe cannot be properly collected in the hot water storage tank after the boiling operation is finished.

  Furthermore, adding a thermistor to collect hot water remaining in the high-temperature side water piping in the hot water storage tank increases the manufacturing cost of the heat pump hot water heater as a whole.

  In view of the above points, an object of the present invention is to provide a heat pump type hot water heater capable of appropriately collecting hot water remaining in a high temperature side water pipe after completion of the boiling operation.

  Another object of the present invention is to provide a method for controlling a heat pump type hot water heater capable of appropriately collecting hot water remaining in the high temperature side water pipe after completion of the boiling operation.

The present invention has been devised in order to achieve the above object, and in the invention according to claim 1, a water-refrigerant heat exchanger that heats hot water by exchanging heat between hot water and high-pressure refrigerant ( 12), a hot water storage tank (20) for storing hot water heated by the water-refrigerant heat exchanger (12), a water-refrigerant heat exchanger (12), and a hot water storage tank ( 20) a water circulation circuit (30) for circulating hot water between
The water circulation circuit (30) flows out of the low-temperature side water passage (31) and the water-refrigerant heat exchanger (12) for guiding hot water flowing out of the hot water storage tank (20) to the water-refrigerant heat exchanger (12) side. The high temperature side water passage (32) for guiding the hot water to the hot water storage tank (20) side, and the hot water flowing out from the water-refrigerant heat exchanger (12) bypass the hot water storage tank (20) and the low temperature side water passage (31 ) Side detour water passage (33), and the water circulation circuit (30) further includes a water pressure feeding means (34) for pumping hot water to the water-refrigerant heat exchanger (12), and a water circulation circuit ( 30) circuit switching means (35) for switching the circuit configuration is disposed,
The circuit switching means (35) includes a tank-side circulation circuit and water-refrigerant heat for guiding hot water flowing out from the water-refrigerant heat exchanger (12) to the hot water storage tank (20) side through the high-temperature side water passage (32). A detour passage side circulation circuit for guiding hot water flowing out from the exchanger (12) to the low temperature side water passage (31) side through the detour water passage (33),
At the time of boiling operation for heating hot water stored in the hot water storage tank (20), the circuit switching means (35) is switched to the tank side circulation circuit, and the water pressure feeding means (34) is operated,
After the boiling operation is completed and until a predetermined switching stop condition is satisfied, the circuit switching means (35) switches to the bypass passage side circulation circuit and the water pressure feeding means (34) is operated to stop the switching. The circuit switching means (35) switches to the tank-side circulation circuit and operates the water pressure feeding means (34) until the predetermined water pressure feeding means stop condition is satisfied after the condition is established, and the water pressure feeding means. It is characterized by a heat pump type water heater that stops the water pressure feeding means (34) when the stop condition is satisfied.

  According to this, the water pressure feeding means (34) is operated in a state where the water circulation circuit (30) is switched to the bypass circuit side circulation circuit after completion of the boiling operation and until the switching stop condition is satisfied. Therefore, the hot hot water flowing out from the water-refrigerant heat exchanger (12) can be guided to the low temperature side water passage (31).

  Further, after the switching stop condition is satisfied and until the water pressure feeding means stop condition is satisfied, the water pressure feeding means (34) is operated in a state where the water circulation circuit (30) is switched to the tank side circulation circuit. The hot hot water remaining in the high temperature water passage (32) can be recovered by being pumped to the hot water storage tank (20).

  Furthermore, when the water pressure feeding means stop condition is satisfied, the water pressure feeding means (34) is stopped, so that it is possible to prevent the low temperature hot water from being pumped to the hot water storage tank (20).

  At this time, since hot hot water is led to the low temperature side water passage (31) after the boiling operation is finished and before the switching stop condition is satisfied, the low temperature side water passage (31) is circulated. It is possible to set a water pumping means stop condition that is established based on a temperature change of the hot water to be performed. That is, a condition that is not based on the hot water temperature detected by the temperature detecting means arranged on the hot water inlet side of the hot water storage tank (20) can be set as the water pressure feeding means stop condition.

  Therefore, as in the prior art, in order to recover the hot water remaining in the hot water passage (32) into the hot water storage tank (20), the hot water storage tank (20) is disposed on the hot water inlet side. There is no need to provide temperature detection means.

  As a result, according to the invention described in this claim, the hot water remaining in the high-temperature side water passage (32) can be stored without increasing the manufacturing cost of the heat pump hot water heater (1) as a whole. A heat pump type hot water heater that can be appropriately collected in the tank (20) can be provided.

  Moreover, in the heat pump type water heater having the above characteristics, a condition that is established based on the incoming water temperature (Twi) detected by the incoming water temperature detecting means (42) may be adopted as the water pressure feeding means stop condition.

  Here, the incoming water temperature detecting means (42) is a temperature detecting means for detecting the temperature of hot water flowing into the water-refrigerant heat exchanger (12), and in a general heat pump hot water heater (1), The detected values are used to determine the control state of each component device of the heat pump cycle (10) and the water pressure feeding means (34).

  Therefore, by adopting a condition established based on the incoming water temperature (Twi) detected by the incoming water temperature detecting means (42) as the water pumping means stop condition, the manufacturing cost of the heat pump hot water heater (1) as a whole can be reduced. It is possible to more reliably suppress the increase.

  Specifically, a condition that is established when the incoming water temperature (Twi) detected by the incoming water temperature detecting means (42) becomes equal to or higher than a predetermined reference inlet side temperature (KTwi) is adopted as the water pumping means stop condition. May be. Moreover, when the amount of increase (ΔTwi) per unit time of the incoming water temperature (Twi) detected by the incoming water temperature detecting means (42) is equal to or greater than a predetermined reference increase amount (ΔKTwi) as the water pressure feeding means stop condition. The conditions that hold may be adopted.

In the invention according to claim 6, a heat pump cycle (10) having a water-refrigerant heat exchanger (12) that heats hot water by exchanging heat between hot water and high-pressure refrigerant, and water-refrigerant heat exchange. A hot water storage tank (20) for storing hot water heated by the heater (12), and a water circulation circuit (30) for circulating hot water between the water-refrigerant heat exchanger (12) and the hot water storage tank (20) And comprising
The water circulation circuit (30) flows out of the low-temperature side water passage (31) and the water-refrigerant heat exchanger (12) for guiding hot water flowing out of the hot water storage tank (20) to the water-refrigerant heat exchanger (12) side. The high temperature side water passage (32) for guiding the hot water to the hot water storage tank (20) side, and the hot water flowing out from the water-refrigerant heat exchanger (12) bypass the hot water storage tank (20) and the low temperature side water passage (31 ) Side detour water passage (33) leading to the water circulation circuit (30), the water circulation means (34) for feeding hot water to the water-refrigerant heat exchanger (12), and the water circulation circuit (30) The circuit switching means (35) for switching the circuit configuration is arranged,
The circuit switching means (35) includes a tank-side circulation circuit and water-refrigerant heat for guiding hot water flowing out from the water-refrigerant heat exchanger (12) to the hot water storage tank (20) side through the high-temperature side water passage (32). It is a control method for a heat pump type hot water heater that switches between a detour passage side circulation circuit that guides hot water flowing out from the exchanger (12) to a low temperature side water passage (31) side through a detour water passage (33). And
During the boiling operation for heating the hot water stored in the hot water storage tank (20), the water pressure feeding means (34) is operated while the circuit switching means (35) is switched to the tank side circulation circuit,
Further, after the boiling operation is finished, the first pressure feeding means for operating the water pressure feeding means (34) in a state where the water circulation circuit (30) is switched to the bypass passage side circulation circuit until a predetermined switching stop condition is satisfied. Operating steps (S1-S3);
After the switching stop condition is established, the second pumping means operation is performed to operate the water pressure feeding means (34) in a state where the water circulation circuit (30) is switched to the tank side circulation circuit until a predetermined water pressure feeding means stop condition is established. Steps (S4 to S6);
And a pumping means stop step (S7) for stopping the water pumping means (34) when the water pumping means stop condition is satisfied.

  According to this, hot water remaining in the high-temperature side water passage (32) without increasing the manufacturing cost of the heat pump hot water heater (1) as a whole, as in the invention described in claim 1. Can be provided in the hot water storage tank (20).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is an overall configuration diagram of a heat pump type water heater according to an embodiment. It is a block diagram which shows the electric control part of the heat pump type water heater of one Embodiment. It is a flowchart which shows the principal part of the control processing of the heat pump type water heater of one Embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The heat pump type hot water heater 1 of the present embodiment includes a heat pump cycle 10, a hot water storage tank 20, a water circulation circuit 30 and the like, as shown in the overall configuration diagram of FIG.

  The heat pump cycle 10 is a vapor compression refrigeration cycle for heating hot water. The hot water storage tank 20 is hot water storage means for storing hot water heated in the heat pump cycle 10. Further, the water circulation circuit 30 is a water circuit that circulates hot water between the water-refrigerant heat exchanger 12 and the hot water storage tank 20 of the heat pump cycle 10.

  More specifically, the heat pump cycle 10 is configured by sequentially connecting a compressor 11, a water-refrigerant heat exchanger 12, an electric expansion valve 13, and an evaporator 14 with piping.

  Further, in the heat pump cycle 10 of the present embodiment, carbon dioxide is employed as the refrigerant, and the high-pressure side refrigerant pressure in the cycle from the discharge port side of the compressor 11 to the inlet side of the electric expansion valve 13 is the critical pressure of the refrigerant. This constitutes the supercritical refrigeration cycle. This refrigerant is mixed with refrigerating machine oil for lubricating the compressor 11, and a part of the refrigerating machine oil circulates in the cycle together with the refrigerant.

  The compressor 11 sucks the refrigerant in the heat pump cycle 10 and compresses and discharges the refrigerant until the pressure becomes equal to or higher than the critical pressure. The compressor 11 is an electric compressor that drives a fixed displacement compression mechanism with a fixed discharge capacity by an electric motor. is there. Specifically, various compression mechanisms such as a scroll type compression mechanism and a vane type compression mechanism can be adopted as the fixed capacity type compression mechanism.

  The electric motor has its rotational speed controlled by a control signal output from the control device 40 to be described later, and may employ either an AC motor or a DC motor. And the refrigerant | coolant discharge capability of the compressor 11 is changed by this rotation speed control. Therefore, the electric motor of the present embodiment constitutes the discharge capacity changing means of the compressor 11.

  A refrigerant passage 12 a inlet side of the water-refrigerant heat exchanger 12 is connected to the discharge port of the compressor 11. The water-refrigerant heat exchanger 12 has a refrigerant passage 12a for circulating the high-pressure refrigerant discharged from the compressor 11, and a water passage 12b for circulating hot water circulating through the water circulation circuit 30, and circulates through the refrigerant passage 12a. It is a heat exchanger for heating which heat-exchanges hot water by heat-exchanging high-pressure refrigerant and hot water flowing through the water passage 12b.

  As a specific configuration of such a water-refrigerant heat exchanger 12, a configuration in which a water passage 12b is arranged on the outer periphery of the refrigerant passage 12a to exchange heat between the refrigerant and the cooling water, or a meandering passage through which refrigerant flows as the refrigerant passage 12a. Or a plurality of tubes, a water passage 12b is formed between adjacent tubes, and a corrugated fin or a plate fin that promotes heat exchange between the refrigerant and the cooling water is used. May be.

  Further, in the present embodiment, the water-refrigerant heat exchanger 12 is a counter flow type heat exchanger in which the flow direction of the refrigerant flowing through the refrigerant passage 12a and the flow direction of hot water flowing through the water passage 12b are counterflows. Is adopted.

  In such a counter-flow heat exchanger, heat is exchanged between the refrigerant on the refrigerant passage 12a inlet side and the hot water on the water passage 12b outlet side, and the refrigerant on the refrigerant passage 12a outlet side and the hot water on the water passage 12b inlet side. Therefore, it is possible to secure a temperature difference between the hot water and the refrigerant over the entire heat exchange region and improve the heat exchange efficiency.

  In addition, since the heat pump cycle 10 of the present embodiment constitutes a supercritical refrigeration cycle as described above, the refrigerant remains in the supercritical state without being condensed in the refrigerant passage 12a of the water-refrigerant heat exchanger 12. Dissipate heat.

  The inlet side of the electric expansion valve 13 is connected to the outlet side of the refrigerant passage 12 a of the water-refrigerant heat exchanger 12. The electric expansion valve 13 is a decompression unit that decompresses the refrigerant flowing out of the refrigerant passage 12a.

  More specifically, the electric expansion valve 13 is configured by a variable throttle mechanism having a valve body that can change the throttle opening degree and an electric actuator that changes the throttle opening degree of the valve body. The operation of the electric actuator is controlled by a control signal output from the control device 40.

  The refrigerant inlet side of the evaporator 14 is connected to the outlet side of the electric expansion valve 13. The evaporator 14 performs heat exchange between the low-pressure refrigerant decompressed by the electric expansion valve 13 and the outside air (outdoor air) blown by the blower fan 14a, thereby evaporating the low-pressure refrigerant and exerting an endothermic effect. This is an outdoor heat exchanger. The blower fan 14 a is an outside air blower whose rotation speed (amount of blown air) is controlled by a control voltage output from the control device 40.

  The refrigerant outlet of the evaporator 14 is connected to the suction port side of the compressor 11. Note that the gas-liquid refrigerant flowing out of the evaporator 14 is separated into a refrigerant path from the refrigerant outlet side of the evaporator 14 to the suction port side of the compressor 11, and the separated gas-phase refrigerant is separated from the suction port of the compressor 11. An accumulator that stores the separated liquid-phase refrigerant as an excess refrigerant may be disposed.

  In addition, each component apparatus 11-14 of the heat pump cycle 10 enclosed with the broken line of FIG. 1, the ventilation fan 14a, etc. are accommodated in one housing | casing, and are comprised integrally as the heat pump unit 100. FIG. Furthermore, the heat pump unit 100 is disposed outdoors.

  The hot water storage tank 20 is formed of a metal having excellent corrosion resistance (for example, stainless steel), and has a heat insulating structure in which the outer periphery is covered with a heat insulating material or a vacuum heat insulating structure with a double tank, and keeps hot hot water hot for a long time. It is a hot water tank that can. Moreover, the hot water storage tank 20 of this embodiment is formed in the hollow cylinder shape, and is formed in the vertically long shape where an axial direction extends in a substantially vertical direction.

  Connected to the upper side of the hot water storage tank 20 are an outflow pipe 21 through which hot water stored in the hot water storage tank 20 flows out and a high temperature side water pipe 32 constituting the water circulation circuit 30. On the other hand, on the lower side of the hot water storage tank 20, a water supply pipe 22 into which tap water is introduced and a low temperature side water pipe 31 constituting the water circulation circuit 30 are connected.

  Further, the hot water outlet that is the most downstream part of the hot water flow in the high temperature side water pipe 32 and the hot water inlet that is the most upstream part of the hot water flow in the outflow pipe 21 flow into the hot water storage tank 20 from the high temperature side water pipe 32. The hot water supplied immediately after the hot water is arranged close to each other so that at least a part of the hot water can directly flow into the outflow pipe 21.

  On the other hand, the tap water outlet which is the most downstream part of the tap water flow of the water supply pipe 22 and the hot water inlet which is the most upstream part of the hot water flow of the low temperature side water pipe 31 flowed into the hot water storage tank 20 from the water supply pipe 22. They are arranged close to each other to such an extent that at least a part of the low-temperature tap water immediately after that can flow directly into the low-temperature side water pipe 31.

  A temperature control valve (not shown) is connected to the outlet side of the outflow pipe 21. And by this temperature control valve, the hot water supply water which flowed out of the hot water storage tank 20 and the low temperature tap water are mixed, and the hot water supply water adjusted to the target hot water temperature is arranged in a kitchen, a bathroom, etc. Hot water is discharged from hot water supply terminals such as taps and showers.

  Note that at least a part of the hot water storage tank 20, the outflow pipe 21, at least a part of the water supply pipe 22, etc. enclosed by the one-dot chain line in FIG. 1 are accommodated in one housing and integrated as a tank unit 200. It is configured. Further, the tank unit 200 is disposed outside the room, similarly to the heat pump unit 100.

  The water circulation circuit 30 includes a low temperature side water pipe 31, a high temperature side water pipe 32, and a detour water pipe 33. The low temperature side water pipe 31 is a low temperature side water passage that guides the low temperature hot water flowing out of the hot water storage tank 20 to the water passage 12 b inlet side of the water-refrigerant heat exchanger 12. The high temperature side water pipe 32 is a high temperature side water passage that guides hot hot water flowing out from the outlet side of the water passage 12b of the water-refrigerant heat exchanger 12 to the hot water storage tank 20 side.

  The bypass water pipe 33 is a bypass water path that guides hot water flowing out from the water passage 12 b of the water-refrigerant heat exchanger 12 to the low temperature side water pipe 31 by bypassing the hot water storage tank 20. More specifically, the detour water pipe 33 of the present embodiment has a hot water supply at a position closer to the hot water outlet (hot water storage tank side) than the hot water inlet (water-refrigerant heat exchanger 12 side) of the high temperature side water pipe 32. It arrange | positions so that water may be guide | induced to the position closer to a hot water supply inlet (hot water storage tank side) than the hot water supply water outlet (water-refrigerant heat exchanger 12 side) of the low temperature side water piping 31. FIG.

  A water circulation pump 34 is disposed in the low temperature side water pipe 31. The water circulation pump 34 is water pressure feeding means that sucks hot water flowing out from the lower side of the hot water storage tank 20 and pumps it to the water passage 12b side of the water-refrigerant heat exchanger 12. The rotation speed (water pressure feeding capacity) of the water circulation pump 34 is controlled by a control voltage output from the control device 40.

  A water circuit switching valve 35 is disposed in the high temperature side water pipe 32. The water circuit switching valve 35 is circuit switching means for switching the circuit configuration of the water circulation circuit 30. The water circuit switching valve 35 of the present embodiment is configured by an electric three-way valve, and its operation is controlled by a control voltage output from the control device 40.

  Further, the water circuit switching valve 35 is a circuit (tank side circulation circuit) for guiding hot water flowing out from the water passage 12b of the water-refrigerant heat exchanger 12 to the hot water storage tank 20 side through the high temperature side water pipe 32 and water- It functions to switch between a circuit (detour passage side circulation circuit) that guides hot water flowing out from the water passage 12b of the refrigerant heat exchanger 12 to the inlet side of the low temperature side water piping 31 via the bypass water piping 33.

  More specifically, when the water circulation pump 34 is operated while the water circuit switching valve 35 is switched to the tank side circulation circuit, the hot water flowing out from the lower side of the hot water storage tank 20 is converted into the low temperature side water pipe 31 → It flows in the order of the water passage 12 b of the water-refrigerant heat exchanger 12 → the high temperature side water pipe 32 and flows into the upper side of the hot water storage tank 20.

  On the other hand, when the water circulation pump 34 is operated while the water circuit switching valve 35 is switched to the bypass passage side circulation circuit, the hot water flowing out from the bypass water pipe 33 is transferred to the low temperature side water pipe 31 → water-refrigerant heat exchange. It flows in the order of the water passage 12b → high-temperature side water pipe 32 of the vessel 12 and flows into the detour water pipe 33 again through the water circuit switching valve 35.

  In the present embodiment, the water circulation pump 34 disposed in the water circulation circuit 30 is accommodated in the housing of the heat pump unit 100 as indicated by a broken line in FIG. Further, the detour water pipe 33 and the water circuit switching valve 35 are accommodated in the casing of the tank unit 200 as shown by a one-dot chain line in FIG.

  Here, although the heat pump unit 100 and the tank unit 200 of the present embodiment are both arranged outdoors, the relative positional relationship between the heat pump unit 100 and the tank unit 200 is the installation of the individual heat pump hot water heaters 1. It depends on the location (installation conditions).

  Therefore, in the present embodiment, the length and shape of the low temperature side water pipe 31 and the high temperature side water pipe 32 are changed according to the installation location (installation conditions) of each heat pump type hot water heater 1, The water-refrigerant heat exchanger 12 and the hot water storage tank 20 in the tank unit 200 are securely connected.

  In other words, in the water circulation circuit 30 of the present embodiment, the portion of the low temperature side water pipe 31 from the connection portion with the bypass water pipe 33 to the inlet side of the water circulation pump 34 and the water-refrigerant heat of the high temperature side water pipe 32. The part from the outlet side of the water passage 12b of the exchanger 12 to the inlet side of the water circuit switching valve 35 has an appropriate length and shape according to the installation location (installation conditions) of each heat pump type hot water heater 1.

  On the other hand, the bypass water pipe 33 has the same length and shape regardless of the individual heat pump type hot water heaters 1, as is apparent from the fact that it is housed in the casing of the tank unit 200.

  Next, the outline of the electric control unit of the present embodiment will be described with reference to the block diagram of FIG. The control device 40 is composed of a well-known microcomputer including a CPU, a ROM, a RAM and the like and its peripheral circuits. Then, various calculations and processes are performed based on the control program stored in the ROM, and the operation of various control target devices connected to the output side is controlled.

  Various devices to be controlled such as the electric motor of the compressor 11, the electric actuator of the electric expansion valve 13, the blower fan 14 a, the water circulation pump 34, and the water circuit switching valve 35 are connected to the output side of the control device 40. .

  On the other hand, a tank internal temperature sensor 41, an incoming water temperature sensor 42, a boiling temperature sensor 43, an evaporator temperature sensor 44, an outside air temperature sensor 45, a discharge pressure sensor 46, and the like are connected to the input side of the control device 40. A detection signal of the sensor group is input to the control device 40.

  The tank internal temperature sensor 41 is a tank internal temperature detection means for detecting the temperature of hot water stored in the hot water storage tank 20. More specifically, the in-tank temperature sensor 41 of the present embodiment is composed of a plurality of (in this embodiment, five) temperature sensors arranged in the vertical direction in the hot water storage tank 20.

  Thereby, in the control apparatus 40, the temperature of the hot water supply according to the water level in the hot water storage tank 20, and the temperature distribution in the hot water storage tank 20 can be detected by the output signals of the plurality of tank internal temperature sensors 41.

  The incoming water temperature sensor 42 is an incoming water temperature detecting means for detecting an incoming water temperature Twi which is a hot water supply water temperature on the inlet side of the water passage 12 b of the water-refrigerant heat exchanger 12. The boiling temperature sensor 43 is a boiling temperature detection means for detecting a boiling temperature Two which is the temperature of hot water supply water on the outlet side of the water passage 12b.

  The evaporator temperature sensor 44 is an evaporator temperature detecting unit that detects a refrigerant evaporation temperature (temperature of the evaporator 14) Te in the evaporator 14. More specifically, the evaporator temperature sensor 44 of the present embodiment detects the refrigerant temperature in the evaporator 14. Of course, as the evaporator temperature detecting means, a temperature detecting means for detecting the heat exchange fin temperature of the evaporator 14 may be adopted, or a temperature detecting means for detecting the temperature of other parts of the evaporator 14 may be adopted. Also good.

  The outside air temperature sensor 45 is an outside air temperature detecting unit that detects an outside air temperature Tam that is the temperature of the outside air that exchanges heat with the low-pressure refrigerant in the evaporator 14. The discharge pressure sensor 46 is discharge refrigerant pressure detection means for detecting the discharge refrigerant pressure (high-pressure side refrigerant pressure) Pd discharged from the compressor 11.

  Further, a remote controller (operation panel) 50 disposed in the room is connected to the input side of the control device 40. The remote controller 50 includes an operation switch 50a for outputting an operation request signal for requesting the operation of the heat pump type hot water heater 1 and a stop request signal for requesting a stop, and the temperature of hot water discharged from each hot water supply terminal (target hot water temperature). A temperature setting switch 50b and the like are provided, and operation signals of these switches are input to the control device 40.

  Note that the control device 40 of the present embodiment is configured integrally with control means for controlling various control target devices connected to the output side of the control device 40. The configuration (hardware and software) for controlling the operation constitutes a control means for controlling the operation of each control target device.

  For example, in the control device 40, the configuration (hardware and software) for controlling the operation of the water circulation pump 34 (water pressure feeding capacity of the water circulation pump 34) constitutes the pressure feeding capacity control means 40a. The configuration for controlling the operation constitutes the water circuit switching control means 40b.

  Further, the pumping capacity control means 40a, the water circuit switching control means 40b, etc. may be configured by another device with respect to the control device 40, or the control device for controlling the operation of the heat pump cycle 10 constituent device in the control device 40. As a heat pump side control device, the control device 40 may be configured by another device.

  Next, the operation of the heat pump type water heater 1 of the present embodiment having the above configuration will be described. When the operation switch 50a of the remote controller 50 is turned on in a state where power is supplied to the heat pump type hot water heater 1 from the outside, the control device 40 executes a control process (control program) stored in advance in the storage circuit.

  In the main routine of this control process, the boiling operation control process for storing hot water heated by the water-refrigerant heat exchanger 12 of the heat pump cycle 10 in the hot water storage tank 20 is executed.

  In the boiling operation, the control device 40 controls the operation of the water circuit switching valve 35 so that the water circulation circuit 30 becomes a tank-side circulation circuit. Further, the control device 40 reads the operation signal of the remote controller 50 and the detection signal detected by the sensor groups 41 to 46 and the like, and based on the read operation signal and detection signal, various control target devices 11 of the heat pump cycle 10, 13 and 14a and the control signal or control voltage output to the water circulation pump 34 is determined.

  For example, the control signal output to the compressor 11 (specifically, the electric motor of the compressor 11) is stored in the control device 40 in advance based on the detected outside air temperature Tam detected by the outside air temperature sensor 45. Determined with reference to the control map. More specifically, the target rotational speed (target refrigerant discharge capacity) of the compressor 11 is determined to increase as the outside air temperature Tam decreases.

  The control signal output to the electric expansion valve 13 (specifically, the electric actuator of the electric expansion valve 13) is the discharge refrigerant pressure detected by the discharge pressure sensor 46 using a feedback control method or the like. Pd is determined to be the target high pressure. The target high pressure is determined so that the coefficient of performance (COP) of the heat pump cycle 10 becomes a maximum value with reference to a control map stored in advance in the control device 40 based on the outside air temperature Tam and the discharge refrigerant pressure Pd. Is done.

  The control voltage output to the blower fan 14a is determined with reference to a control map stored in advance in the control device 40 based on the outside air temperature Tam. Moreover, about the control voltage output to the water circulation pump 34, using the feedback control method etc., the boiling temperature Two detected by the boiling temperature sensor 43 is set to the target boiling temperature Tw (in this embodiment, 90 degreeC). To be determined.

  Here, the target boiling temperature Tw during the boiling operation is equal to or higher than the temperature at which the temperature of the hot water stored in the hot water storage tank 20 by the boiling operation can kill Legionella in the hot water storage tank 20 or Legionella. The temperature is set to be higher than the temperature at which fungal growth can be suppressed.

  And the control apparatus 40 outputs the control signal and control voltage which were determined as mentioned above to various control object apparatus. After that, until a predetermined boiling end condition is satisfied, a control routine such as reading a detection signal and an operation signal → determining a control state of various control target devices → outputting control voltages and control signals to various control target devices Is repeated.

  Accordingly, during the boiling operation, the high-temperature and high-pressure refrigerant discharged from the compressor 11 of the heat pump cycle 10 flows into the refrigerant passage 12a of the water-refrigerant heat exchanger 12 and is pumped to the water passage 12b by the water circulation pump 34. Exchange heat with hot water. Thereby, the hot water flowing into the water passage 12b is heated so as to reach the target boiling temperature Tw.

  The high-pressure refrigerant flowing out of the water-refrigerant heat exchanger 12 is decompressed by the electric expansion valve 13. The refrigerant decompressed by the electric expansion valve 13 flows into the evaporator 14, absorbs heat from the outside air blown from the blower fan 14a, and evaporates. The refrigerant flowing out of the evaporator 14 is sucked into the compressor 11 and compressed again.

  On the other hand, the hot water heated by the water-refrigerant heat exchanger 12 flows into the upper side of the hot water storage tank 20 via the high temperature side water pipe 32 and is stored in the hot water storage tank 20. In addition, since the hot water storage tank 20 of this embodiment is formed in the vertically long shape in which the axial direction extends in a substantially vertical direction, the hot water in the hot water storage tank 20 when the boiling operation is finished is supplied from above. A temperature distribution is generated in which the temperature gradually decreases downward.

  Further, when the end condition of the boiling operation is satisfied, the control device 40 stops the operation of the compressor 11 and the water circulation pump 34, and further executes a sub-routine for hot water collection operation shown in the flowchart of FIG. Here, each control step in the flowchart shown in FIG. 3 constitutes various function realizing means of the control device 40.

  First, in step S1, the operation of the water circuit switching valve 35 is controlled so that the water circulation circuit 30 is switched to the bypass passage side circulation circuit. In the subsequent step S2, the water circulation pump 34 is operated so as to exhibit a predetermined water pressure feeding capability, and the process proceeds to step S3. In step S3, it is determined whether or not a predetermined switching stop condition is satisfied.

  More specifically, in step S3 of the present embodiment, it is determined that the switching stop condition is satisfied when the time during which the water circulation pump 34 is operated exceeds a predetermined reference time, and the process proceeds to step S4. . This reference time is determined so that at least a part of the hot hot water in the high temperature side water pipe 32 flows into the low temperature side water pipe 31 via the water circuit switching valve 35 and the bypass water pipe 33. Yes.

  As described above, the bypass water pipe 33 of the present embodiment has the same length and shape regardless of the individual heat pump type hot water heaters 1. Accordingly, the time required to allow a part of the hot water supply water in the high temperature side water pipe 32 to flow into the low temperature side water pipe 31 can be easily determined, and according to the individual heat pump type water heater 1. The same value can be used.

  In step S4, the operation of the water circuit switching valve 35 is controlled so that the water circulation circuit 30 is switched to the tank side circulation circuit. In the subsequent step S5, the detection signal of the incoming water temperature sensor 42 is read, and the process proceeds to step S6. In step S6, it is determined whether or not a predetermined water pumping means stop condition is satisfied.

  More specifically, in step S6 of the present embodiment, when the incoming water temperature Twi detected by the incoming water temperature sensor 42 is equal to or higher than a predetermined reference incoming water temperature KTwi, it is determined that the water pumping means stop condition is satisfied. Then, the process proceeds to step S7. On the other hand, when it is determined in step S6 that the water pumping means stop condition is not satisfied, the process returns to step S5. In step S7, the operation of the water circulation pump 34 is stopped, and the process returns to the main routine.

  As is clear from the above description, in steps S1 to S3, the water circulation pump 34 is operated in a state in which the water circulation circuit 30 is switched to the bypass passage side circulation circuit until the switching stop condition is satisfied after completion of the boiling operation. I am letting. In Steps S4 to S6, the water circulation pump 34 is operated in a state where the water circulation circuit 30 is switched to the bypass circuit side circulation circuit until the water pressure feeding means stop condition is satisfied after the switch stop condition is satisfied. Further, in the control step S7, the water circulation pump 34 is stopped when the water pumping means stop condition is satisfied.

  Therefore, the control steps S1 to S3 of the present embodiment correspond to the first pumping means operation step described in the claims, and the control steps S4 to S6 are the second steps described in the claims. The control step S7 corresponds to the pumping means operation step, and the control step S7 corresponds to the pumping means stop step.

  Further, in the control device 40 of the present embodiment, using the timer means or the like, the boiling operation is executed in the midnight power time zone (for example, from 23:00 to 7:00 the next morning) in which inexpensive commercial power can be used at night. Yes. Thereby, in the heat pump type hot water heater 1 of this embodiment, the electric power cost required in order to boil the hot water stored in the hot water storage tank 20 is reduced.

  Next, when hot water from various hot water supply terminals is requested, the control device 40 sets the target of each hot water supply terminal in which the temperature of hot water discharged from the various hot water supply terminals is set by the temperature setting switch 50 b of the remote controller 50. The operation of the temperature adjustment valve is controlled so as to reach the tapping temperature. Note that “when hot water is requested from various hot water supply terminals” in the present embodiment corresponds to “when a user performs hot water operation (opening operation) such as a faucet or shower”.

  As described above, in the heat pump type hot water heater 1 of the present embodiment, the hot water hot water stored in the hot water storage tank 20 is mixed with the tap water so that the hot water adjusted to the user's desired temperature is supplied to each hot water supply terminal. Can be discharged from the hot water.

  Here, like the heat pump type water heater 1 of this embodiment, when the operation of the compressor 11 and the water circulation pump 34 is stopped when the end condition during the boiling operation is satisfied, the water-refrigerant heat exchanger 12 is stopped. High temperature hot water heated by the water-refrigerant heat exchanger 12 remains in the high temperature side water pipe 32 extending from the outlet side of the water passage 12b to the inlet side of the hot water storage tank 20.

  As described above, when high-temperature hot water supply water remains in the high-temperature water pipe 32, the heat of the hot water is radiated to the atmosphere through the high-temperature water pipe 32 over time. That is, the energy consumed for heating the hot water is lost without being effectively used by the user.

  As a means for suppressing such energy loss, the operation of the water circulation pump 34 is continued until a predetermined time elapses after the boiling operation end condition is established, and hot hot water in the high temperature side water pipe 32 is stored. A means for recovering by pumping into the tank 20 is conceivable.

  However, as described above, the length and shape of the high temperature side water pipe 32 have individual differences for each heat pump type water heater. Therefore, even if the operation of the water circulation pump 34 is continued until a predetermined time elapses after the boiling operation end condition is satisfied, the hot water supply may not be properly recovered.

  For example, when the length of the high-temperature side water pipe 32 is relatively long, a large amount of hot water supply water is collected in the hot water storage tank 20 even if the operation of the water circulation pump 34 is continued until a predetermined time elapses. Otherwise, there is a risk of remaining in the high temperature side water pipe 32. On the other hand, when the length of the high temperature side water pipe 32 is relatively short, if the operation of the water circulation pump 34 is continued until a predetermined time elapses, low temperature hot water will flow into the hot water storage tank 20. There is a fear.

  On the other hand, in the heat pump type water heater 1 of the present embodiment, the water circulation circuit 30 is switched to the bypass passage side circulation circuit after the boiling operation is finished and until the switching stop condition is satisfied. Since the water circulation pump 34 is operated, the hot hot water flowing out from the water-refrigerant heat exchanger 12 can be guided to the low temperature side water pipe 31.

  At this time, in the heat pump water heater 1 of the present embodiment, the length and shape of the bypass water pipe 33 are the same predetermined length and shape regardless of individual differences of the heat pump water heater. . Therefore, by adopting a condition that is established when the time when the water circulation pump 34 is operated exceeds the reference time as the switching stop condition, it is ensured that at least a part of the hot hot water in the high temperature side water pipe 32 is Can flow into the low temperature side water pipe 31.

  Further, after the switching stop condition is satisfied and until the water pumping means stop condition is satisfied, the water circulation pump 34 is operated in a state where the water circulation circuit 30 is switched to the tank side circulation circuit. The hot hot water remaining in the hot water 32 can be pumped to the hot water storage tank 20.

  At this time, in the present embodiment, a condition that is established when the incoming water temperature Twi detected by the incoming water temperature sensor 42 is equal to or higher than the reference incoming water temperature KTwi is adopted as the water pumping means stop condition. Therefore, almost all of the hot water supply water remaining in the high temperature side water pipe 32 can be recovered in the hot water storage tank 20.

  More specifically, the water pumping means stop condition of the present embodiment is that the hot hot water flowing into the low temperature side water pipe 31 through the bypass water pipe 33 moves to the inlet side of the water-refrigerant heat exchanger 12. This is established when the incoming water temperature Twi is raised. Therefore, in the water circulation pump 34, an amount of hot water supply corresponding to the capacity in the passage from the connection portion of the low temperature side water piping 31 to the bypass water piping 33 to the inlet side of the water passage 12 b of the water-refrigerant heat exchanger 12. Will be pumped.

  Here, the length and shape of the low-temperature side water pipe 31 and the length and shape of the high-temperature side water pipe 32 are different from each other depending on the individual heat pump type water heater, but the low-temperature side water pipe 31 is different from the bypass water pipe 33. The length of the passage from the connecting portion to the inlet side of the water passage 12b of the water-refrigerant heat exchanger 12 and the water circuit switching valve 35 from the outlet side of the water passage 12b of the water-refrigerant heat exchanger 12 of the high-temperature side water pipe 32. The length of the passage leading to can be set to an equivalent length.

  That is, the capacity in the passage from the connection portion of the low temperature side water pipe 31 to the bypass water pipe 33 to the inlet side of the water passage 12 b of the water-refrigerant heat exchanger 12 and the water-refrigerant heat of the high temperature side water pipe 32. The capacity in the passage from the outlet side of the water passage 12b of the exchanger 12 to the water circuit switching valve 35 can be set to be equal. Therefore, almost the entire amount of hot hot water remaining in the high temperature side water pipe 32 can be recovered in the hot water storage tank 20.

  Further, when the water pressure feeding means stop condition is satisfied, the water circulation pump 34 is stopped, so that the operation of the water circulation pump 34 is continued unnecessarily and the low-temperature hot water supply is pumped to the hot water storage tank 20. Can be suppressed.

  As described above, in the heat pump type hot water heater 1 of the present embodiment, the hot hot water is led to the low temperature side water pipe 31 after the boiling operation is finished and before the switching stop condition is satisfied. In addition, it is possible to set water pumping means stop conditions that are established based on the temperature change of the hot water flowing through the low temperature side water pipe 31.

  That is, a condition that is not based on the hot water temperature detected by the temperature detection means arranged on the hot water supply inlet side of the hot water storage tank 20 can be set as the water pumping means stop condition. Therefore, as in the prior art, in order to recover the hot water remaining in the high temperature side water pipe 32 into the hot water storage tank 20, it is necessary to provide a temperature detection means disposed on the hot water inlet side of the hot water storage tank 20. There is no.

  As a result, according to the heat pump type hot water heater 1 described in the present embodiment, the hot water remaining in the high temperature side water pipe 32 is stored as hot water without increasing the manufacturing cost of the heat pump type hot water heater 1 as a whole. The heat pump type hot water heater 1 that can be appropriately collected in the tank 20 can be provided.

  In other words, according to the control method for the heat pump type hot water heater 1 described in the present embodiment, the hot water supply remaining in the high temperature side water pipe 32 without causing an increase in the manufacturing cost of the heat pump type hot water heater 1 as a whole. Water can be appropriately collected in the hot water storage tank 20.

  In the present embodiment, the operation of the compressor 11 and the water circulation pump 34 is stopped when the end condition of the boiling operation is satisfied. That is, the water circulation pump 34 is stopped after the boiling operation is finished and before the water circulation circuit 30 is switched to the bypass passage side circulation circuit. Therefore, it is possible to collect the entire amount of hot hot water remaining in the hot water pipe 32 in the hot water storage tank 20 more reliably.

  If the water circulation pump 34 is not stopped after completion of the boiling operation and before the water circulation circuit 30 is switched to the bypass passage side circulation circuit, when the boiling operation termination condition is satisfied, It is desirable to switch the water circulation circuit 30 from the tank side circulation circuit to the bypass passage side circulation circuit.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention.

  (1) In the above-described embodiment, an example has been described in which the condition that is established when the time when the water circulation pump 34 is operated after the end of the boiling operation is equal to or longer than the reference time is used as the switching stop condition. The stop condition is not limited to this, and a condition that is established based on a detection signal from other temperature detection means provided in the heat pump type water heater 1 may be adopted.

  For example, if the heat pump water heater 1 includes a detour water pipe temperature sensor (detour water pipe temperature detection means) that detects the temperature of hot water flowing through the detour water pipe 33 (detour water passage), A condition that is established when the temperature of the hot water detected by the bypass water pipe temperature sensor becomes equal to or higher than a predetermined reference bypass water pipe temperature after the boiling operation is finished may be adopted.

  Further, if the heat pump water heater 1 is provided with a detour water pipe flow sensor (detour water pipe flow rate detecting means) for detecting the flow rate of hot water flowing through the detour water pipe 33 (detour water passage), as a switching stop condition, A condition that is established when the flow rate of hot water detected by the bypass water pipe flow rate sensor becomes equal to or higher than a predetermined reference bypass water pipe flow rate after the boiling operation is completed may be employed.

  (2) In the above-described embodiment, the condition that is satisfied when the incoming water temperature Twi detected by the incoming water temperature sensor 42 after the end of the boiling operation is equal to or higher than a predetermined reference incoming water temperature KTwi as the water pumping means stop condition. Although the example which employ | adopted was demonstrated, water pumping means stop conditions are not limited to this.

  For example, a storage means for storing the incoming water temperature Twi detected by the incoming water temperature sensor 42 per unit time is provided, and after completion of the boiling operation, the incoming water temperature Twi detected by the incoming water temperature sensor 42 per unit time. A condition that is established when the increase amount ΔTwi (a value obtained by subtracting the incoming water temperature Twi_OLD stored in the storage unit from the detected incoming water temperature Twi) is equal to or greater than a predetermined reference upward amount ΔKTwi may be employed.

  (3) In the above-described embodiment, the details of the completion condition of the boiling operation are not described. However, as the completion condition of the boiling operation, for example, the temperature sensor 41 in the tank constituted by a plurality of temperature sensors may be used. Of these, the boiling operation may be terminated when the temperature detected by a predetermined temperature sensor (for example, the temperature sensor disposed on the lowermost side) reaches a predetermined boiling operation end temperature.

  Further, the total amount of heat supplied to the hot water in the hot water storage tank 20 calculated from the boiling temperature Two detected by the boiling temperature sensor 43, the water pressure feeding capacity of the water circulation pump 34, the operation time of the heat pump cycle 10, and the like is obtained. The boiling operation may be terminated when the total heat quantity is equal to or higher than a predetermined reference total heat amount. Further, the boiling operation may be terminated when a predetermined time elapses from the start of the boiling operation.

  (4) In the above-described embodiment, an example in which a faucet, a shower, or the like is provided as a hot water supply terminal has been described. However, a hot water panel for floor heating, a hot water panel for wall heating, or the like may be provided as a hot water supply terminal.

  (5) In the heat pump cycle 10 of the above-described embodiment, carbon dioxide is used as a refrigerant to constitute a supercritical refrigeration cycle. However, the present invention is not limited to this, and a refrigerant such as a fluorocarbon refrigerant or an HC refrigerant is adopted. Thus, a subcritical refrigeration cycle in which the high-pressure side refrigerant pressure of the cycle does not exceed the critical pressure of the refrigerant may be configured.

DESCRIPTION OF SYMBOLS 10 Heat pump cycle 12 Water-refrigerant heat exchanger 20 Hot water storage tank 30 Water circulation circuit 31 Low temperature side water piping 32 High temperature side water piping 33 Detour water piping 34 Water circulation pump 35 Water circuit switching valve

Claims (6)

A heat pump cycle (10) having a water-refrigerant heat exchanger (12) for heating the hot-water supply by exchanging heat between the hot-water supply and the high-pressure refrigerant;
A hot water storage tank (20) for storing hot water heated in the water-refrigerant heat exchanger (12);
A water circulation circuit (30) for circulating hot water between the water-refrigerant heat exchanger (12) and the hot water storage tank (20),
The water circulation circuit (30) includes a low-temperature side water passage (31) for guiding hot water flowing out of the hot water storage tank (20) to the water-refrigerant heat exchanger (12) side, and the water-refrigerant heat exchanger (12). The hot water flowing out from the hot water storage tank (20) and the hot water flowing out from the water-refrigerant heat exchanger (12) bypass the hot water storage tank (20). Detour water passage (33) leading to the low temperature side water passage (31) side,
In the water circulation circuit (30), water pressure feeding means (34) for pumping hot water to the water-refrigerant heat exchanger (12), and circuit switching means (35) for switching the circuit configuration of the water circulation circuit (30). Is placed,
The circuit switching means (35) includes a tank-side circulation circuit that guides hot water flowing out from the water-refrigerant heat exchanger (12) to the hot water storage tank (20) side through the high-temperature side water passage (32). A detour passage side circulation circuit for guiding hot water flowing out from the water-refrigerant heat exchanger (12) to the low temperature side water passage (31) side through the detour water passage (33);
At the time of boiling operation for heating hot water stored in the hot water storage tank (20), the circuit switching means (35) is switched to the tank side circulation circuit, and the water pressure feeding means (34) is operated,
Furthermore, after the boiling operation is completed and until a predetermined switching stop condition is satisfied, the circuit switching means (35) switches to the bypass passage side circulation circuit and the water pressure feeding means (34). And
The circuit switching means (35) switches to the tank-side circulation circuit and the water pressure feeding means (34) is switched after the switching stop condition is satisfied and until a predetermined water pressure feeding means stop condition is satisfied. Operate,
A heat pump type hot water heater characterized by stopping the water pressure feeding means (34) when the water pressure feeding means stop condition is satisfied.   2. The water pressure feeding means (34) is stopped after the end of the boiling operation and before the circuit switching means (35) switches to the bypass passage side circulation circuit. 3. Heat pump water heater.   The switching stop condition is a condition that is satisfied when a time during which the water circulation pump (34) is operated after completion of the boiling operation is equal to or longer than a predetermined reference time. 2. A heat pump type water heater according to 2. An incoming water temperature detecting means (42) for detecting an incoming water temperature of hot water flowing into the water-refrigerant heat exchanger (12);
The water pumping means stop condition is a condition that is satisfied when the incoming water temperature (Twi) detected by the incoming water temperature detecting means (42) is equal to or higher than a predetermined reference incoming water temperature (KTwi). The heat pump type water heater according to any one of claims 1 to 3. An incoming water temperature detecting means (42) for detecting an incoming water temperature of hot water flowing into the water-refrigerant heat exchanger (12);
The water pumping means stop condition is that the rising amount (ΔTwi) per unit time of the incoming water temperature (Twi) detected by the incoming water temperature detecting means (42) is equal to or greater than a predetermined reference rising amount (ΔKTwi). The heat pump type hot water heater according to any one of claims 1 to 3, wherein the condition is satisfied at the time. A heat pump cycle (10) having a water-refrigerant heat exchanger (12) for heating the hot-water supply by exchanging heat between the hot-water supply and the high-pressure refrigerant;
A hot water storage tank (20) for storing hot water heated in the water-refrigerant heat exchanger (12);
A water circulation circuit (30) for circulating hot water between the water-refrigerant heat exchanger (12) and the hot water storage tank (20),
The water circulation circuit (30) includes a low-temperature side water passage (31) for guiding hot water flowing out of the hot water storage tank (20) to the water-refrigerant heat exchanger (12) side, and the water-refrigerant heat exchanger (12). The hot water flowing out from the hot water storage tank (20) and the hot water flowing out from the water-refrigerant heat exchanger (12) bypass the hot water storage tank (20). Detour water passage (33) leading to the low temperature side water passage (31) side,
In the water circulation circuit (30), water pressure feeding means (34) for pumping hot water to the water-refrigerant heat exchanger (12), and circuit switching means (35) for switching the circuit configuration of the water circulation circuit (30). Is placed,
The circuit switching means (35) includes a tank-side circulation circuit that guides hot water flowing out from the water-refrigerant heat exchanger (12) to the hot water storage tank (20) side through the high-temperature side water passage (32). A heat pump type that switches between a bypass passage side circulation circuit that guides hot water flowing out from the water-refrigerant heat exchanger (12) to the low temperature side water passage (31) side through the bypass water passage (33). A method for controlling a water heater,
During the boiling operation for heating the hot water stored in the hot water storage tank (20), the water pressure feeding means (34) is operated while the circuit switching means (35) is switched to the tank side circulation circuit,
Further, after the boiling operation is completed, the water pressure feeding means (34) is operated in a state in which the water circulation circuit (30) is switched to the bypass passage side circulation circuit until a predetermined switching stop condition is satisfied. A first pumping means operating step (S1 to S3);
After the switching stop condition is satisfied, the water pressure feeding means (34) is operated in a state where the water circulation circuit (30) is switched to the tank side circulation circuit until a predetermined water pressure feeding means stop condition is satisfied. 2 pumping means operating steps (S4 to S6);
A control method for a heat pump type water heater, comprising: a pumping means stop step (S7) for stopping the water pumping means (34) when the water pumping means stop condition is satisfied.

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