Heat pump water heater

Abstract

To provide a heat pump water heater that can maximize the use of surplus solar power while reducing initial costs by eliminating the need to obtain weather information when mainly used for heating water during the daytime, thereby minimizing running costs applied to users.SOLUTION: A heat pump water heater according to the present disclosure comprises: a heat pump cycle that heats water; a hot water storage tank; and a controller that controls boiling operation that causes hot water heated by the heat pump cycle to flow into the hot water storage tank. The controller acquires an amount of boiling hot water during a preset daytime period, calculates a boiling time required for performing the boiling operation based on the acquired amount of boiling hot water, and controls the start timing of the boiling operation so that a middle time of the calculated boiling time coincides with a middle time between a start time and an end time of the daytime period.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a heat pump water heater, and more particularly to a solar self-consumption promotion water heater. [Background technology]

[0002] The following Patent Documents 1 to 3 disclose heat pump water heaters that change the ratio of water boiling during the night and day so as to minimize costs including the purchase and sale of electricity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-070129 [Patent Document 2] Patent No. 7132552 [Patent Document 3] JP 2017-009256 A Summary of the Invention [Problem to be solved by the invention]

[0004] The heat pump water heater disclosed in Patent Document 1 aims to utilize the electricity generated by a solar power generation device. For this reason, the heat pump water heater is assumed to be subscribed to an electricity rate menu for night-time storage water heaters, in which the electricity rate is higher during the day than at night. In order to minimize the user's costs, the water heater must be controlled to heat the water during the day when solar power is generated, and heating must be stopped when solar power generation is not expected due to cloudiness or rain. Therefore, when the weather changes during the day's sunshine hours, such as sunny → cloudy → sunny, the heat pump unit must be started and stopped in order to utilize the generated power as little as possible, and losses due to starting and stopping tend to increase. If the number of times the heat pump is started and stopped in a day is limited to avoid losses due to starting and stopping, the utilization of surplus electricity cannot be maximized. In addition, in order to obtain weather information, an information collection unit must be purchased separately from the water heater, which increases not only the running cost but also the initial cost.

[0005] The present disclosure has been made to solve the above-mentioned problems. The purpose of the present disclosure is to provide a heat pump water heater that can maximize the use of surplus solar power while reducing initial costs by eliminating the need to obtain weather information when mainly heating water during the day, thereby minimizing the running costs borne by the user. [Means for solving the problem]

[0006] The heat pump water heater of the present disclosure comprises a heat pump cycle that heats water, a hot water storage tank, and a control device that controls a boiling operation that causes hot water heated by the heat pump cycle to flow into the hot water storage tank, and the control device acquires the amount of boiling water to be generated during a preset daytime period, calculates the boiling time for performing the boiling operation based on the acquired amount of boiling water, and controls the start timing of the boiling operation so that the midpoint of the calculated boiling time coincides with the midpoint between the start time and end time of the daytime period. Effect of the Invention

[0007] Generally, the amount of sunlight peaks around noon, but according to the present disclosure, the water heating operation is performed at a timing that results in the middle of the heating period being close to noon, so the effectiveness of surplus power utilization can be increased. Moreover, since there is no need to purchase an information collection unit to obtain weather information, the initial cost and running cost borne by the user can be minimized. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a heat pump water heater according to a first embodiment. [Diagram 2] 1 is a schematic cross-sectional view of a building in which a heat pump water heater according to a first embodiment is installed. [Diagram 3] 4A, 4B, and 4C are diagrams showing the start timing of a heating operation controlled by a control device in the first embodiment; [Figure 4] 13(a), (b), and (c) are diagrams showing trends of photovoltaic power generation and home power consumption in the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. The same reference numerals are used to designate common or corresponding elements in each drawing, and the description will be simplified or omitted. In the following description, the terms "water," "hot water," "warm water," "hot water," and the like generally refer to liquid water, and can include anything from cold water to boiling water.

[0010] Embodiment 1 Fig. 1 is a diagram showing a heat pump water heater HD according to embodiment 1. The heat pump water heater HD corresponds to a solar power self-consumption promotion type water heater described later.

[0011] The heat pump water heater HD is a storage type heat pump water heater including a heat pump unit 1, a tank unit (also referred to as a "storage unit") 2, and a remote control device 3. The heat pump unit 1 and the tank unit 2 are connected via a heat pump supply pipe 4, a heat pump return pipe 5, and electrical wiring (not shown). The heat pump water heater HD may be for home use, for example, or may be for commercial use such as in a store or facility.

[0012] The heat pump unit 1 corresponds to a heating means for heating water. The heat pump unit 1 includes a refrigerant circuit 10 in which a compressor 11, a water-refrigerant heat exchanger 12, an expansion valve 13, and an air heat exchanger 14 are connected in a ring shape by a refrigerant pipe 15. This refrigerant circuit 10 corresponds to a heat pump cycle for heating water. The water-refrigerant heat exchanger 12 heats water by exchanging heat between the refrigerant compressed by the compressor 11 and the water flowing in from the tank unit 2. The water-refrigerant heat exchanger 12 may further include a configuration capable of exchanging heat between the refrigerant compressed by the compressor 11 and water supplied directly from a water source such as a waterworks. The air heat exchanger 14 exchanges heat between air and the refrigerant. The heat pump unit 1 may further include a fan (not shown) for blowing outside air to the air heat exchanger 14. The heat pump unit 1 further includes an inlet water temperature sensor 16 for detecting the temperature of water flowing into the water-refrigerant heat exchanger 12, a boiling temperature sensor 17 for detecting the boiling temperature, and an outside air temperature sensor 18 for detecting the outside air temperature around the heat pump unit 1.

[0013] The tank unit 2 includes a hot water storage tank 21, a first circulation pump 22, a second circulation pump 23, a bath heat exchanger 24, a switching valve 25, a switching valve 26, a switching valve 27, a switching valve (medium temperature water switching valve) 28, a hot water mixing valve 29, and a bath mixing valve 30.

[0014] The hot water storage tank 21 stores hot water, which is heated water. A water supply port (water inlet) 21a, a water intake port (water outlet) 21b, and a water inlet 21c are provided at the bottom of the hot water storage tank 21. A hot water inlet 21d and a hot water inlet 21e are provided at the top of the hot water storage tank 21. A medium-temperature water inlet 21f and a medium-temperature water inlet 21g are provided at the middle part, which is the middle height part of the hot water storage tank 21.

[0015] Hot water temperature sensors 211, 212, and 213 for detecting the temperature of the hot water are provided at intervals in the vertical direction on the side wall surface of the hot water storage tank 21. The hot water temperature sensor 212 is provided at a position at the same height as the medium temperature water inlet outlet 21df or at a position close to the height of the medium temperature water inlet outlet 21f. The hot water temperature sensor 211 is provided at a higher position than the hot water temperature sensor 212, and the hot water temperature sensor 213 is provided at a lower position than the hot water temperature sensor 212. By detecting the temperature distribution of the hot water in the hot water storage tank 21 with these hot water temperature sensors 211, 212, and 213, the amount of remaining hot water or the amount of stored heat in the hot water storage tank 21 can be grasped.

[0016] Inside the hot water tank 21, temperature stratification can be formed, with the upper side being hotter and the lower side being colder, due to differences in water density caused by temperature. The hot water tank 21 is not limited to being composed of a single tank as shown in the figure, but may be one that includes multiple tanks connected in series. In the following explanation, reference is made to the height direction, i.e., the vertical position, of the hot water tank 21, but if the hot water tank 21 includes multiple tanks connected in series, the vertical position is specified in the entire hierarchy from the top tank to the bottom tank.

[0017] The first circulation pump 22 sends water toward the inlet of the water-refrigerant heat exchanger 12. The second circulation pump 23 is a bath circulation pump or a reheating pump that circulates bath water through various pipes. The second circulation pump 23 sends water from the bathtub 6 toward the bath heat exchanger 24. The bath heat exchanger 24 is a reheating heat exchanger that exchanges heat between the tank water supplied from the hot water storage tank 21 and the bath water from the bathtub 6.

[0018] The switching valve 25 is, for example, an electromagnetically driven four-way valve having inlets A and C ports and outlets B and D ports. The switching valve 25 is configured to be switchable between a flow path state in which heated water supplied from the outlet of the water-refrigerant heat exchanger 12 to the A port is supplied to the switching valve 26 from the B port and a flow path state in which water supplied from the D port is supplied to the low-temperature water return port 21c of the hot water storage tank 21. The switching valve 25 is also configured to be switchable between a flow path state in which water supplied from the C port is supplied to the switching valve 26 from the B port and a flow path state in which water supplied from the C port is supplied to the low-temperature water return port 21c of the hot water storage tank 21 from the D port.

[0019] The switching valve 26 is, for example, an electromagnetically driven four-way valve having an inlet port E and outlet ports F, G, and H. The switching valve 26 is configured to be switchable among a flow path state in which the water supplied from the switching valve 25 to the E port is supplied from the H port to the reheating return port 21c of the hot water storage tank 21, a flow path state in which the water is supplied from the G port to the high-temperature water inlet / outlet 21d of the hot water storage tank 21, and a flow path state in which the water is supplied from the F port to the bath heat exchanger 24.

[0020] The switching valve 27 is, for example, an electromagnetically driven three-way valve having an inlet I port and an inlet J port, and an outlet K port. The switching valve 27 is configured to be switchable between a flow path state in which water supplied from the water intake 21b of the hot water storage tank 21 to the I port is supplied from the K port to the first circulation pump 22, and a flow path state in which water supplied from the bath heat exchanger 24 to the J port is supplied from the K port to the first circulation pump 22.

[0021] The switching valve 28 is, for example, an electromagnetically driven three-way valve having an L port and an N port as inlets and an M port as an outlet. The switching valve 28 is configured to select between medium-temperature water supplied to the L port from the medium-temperature water outlet 21f of the hot water storage tank 21 and low-temperature water supplied to the N port from a water source such as a water supply (hereinafter referred to as the "water supply end"), and supply the selected water from the M port to the hot water supply mixing valve 29 and the bath mixing valve 30. That is, the switching valve 28 switches between a medium-temperature water use state in which medium-temperature water is supplied to the mixing valves 29 and 30, and a low-temperature water use state in which low-temperature water is supplied. The switching valve 28 can mix the medium-temperature water and the low-temperature water and supply the mixture to the mixing valves 29 and 30.

[0022] A pipe (first water supply pipe) 31a having a pressure reducing valve 32 installed therein is connected to the water supply end. The pipe 31a is divided into two pipes 31b and 31c downstream of the pressure reducing valve 32. The pipe (second water supply pipe) 31b is connected to the N port of the switching valve 28. The pipe (third water supply pipe) 31c is connected to the water supply port 21a of the hot water storage tank 21. As a result, the low-temperature water supplied from the water supply end is adjusted to a predetermined pressure by the pressure reducing valve 32, and then supplied to the hot water storage tank 21 and the switching valve 28.

[0023] The hot water mixing valve 29 is composed of an electromagnetically driven three-way valve or the like having a first inlet communicating with the hot water inlet outlet 21d of the hot water storage tank 21, a second inlet communicating with the M port of the switching valve 28, and an outlet communicating with the hot water tap 35 described below. The hot water mixing valve 29 produces hot water at a set temperature set by the remote control device 3 by adjusting the flow rate ratio between the high-temperature water supplied from the hot water storage tank 21 and the low-temperature water or medium-temperature water supplied from the switching valve 28. The produced hot water is supplied via the hot water tap 35 to a faucet (not shown) such as a shower or a faucet used by the user.

[0024] The bath mixing valve 30 is composed of an electromagnetically driven three-way valve or the like having a first inlet that leads to the hot water inlet outlet 21d of the hot water storage tank 21, a second inlet that leads to the M port of the switching valve 28, and an outlet that leads to the bath heat exchanger 24. The bath mixing valve 30 produces hot water at the set temperature set by the remote control device 3 by adjusting the flow rate ratio between the high-temperature water supplied from the hot water storage tank 21 and the low-temperature water or medium-temperature water supplied from the switching valve 28. The produced hot water is supplied to the bathtub 6.

[0025] The outlet of the water-refrigerant heat exchanger 12 is connected to the A port of the switching valve 25 via the return pipe 5 and the pipe 33a. The B port of the switching valve 25 is connected to the E port of the switching valve 26 via the pipe 33b. The F port of the switching valve 26 is connected to the high-temperature water outlet 21e of the hot water storage tank 21 via the pipe 33c and the pipe 33d. The F port is connected to the primary side inlet of the bath heat exchanger 24 via the pipe 33d and the pipe (first tank circulation pipe) 33e. The primary side outlet of the bath heat exchanger 24 is connected to the J port of the switching valve 27 via the pipe (second tank circulation pipe) 33f. The primary side outlet of the bath heat exchanger 24 is also connected to the pipe (medium temperature pipe) 33h connecting the medium temperature water outlet 21f of the hot water storage tank 21 and the L port of the switching valve 28 via the pipe (return pipe) 33g in which the check valve 34 is interposed (medium temperature pipe). The check valve 34 prevents heat from flowing from the middle to the lower part of the hot water tank 21 by blocking the flow from the middle to the lower part of the hot water tank 21. The I port of the switching valve 27 is connected to the water intake port 21b via the pipe 33i. The K port of the switching valve 27 is connected to the suction port of the first circulation pump 22 via the pipe 33j. The discharge port of the first circulation pump 22 is connected to the inlet of the water-refrigerant heat exchanger 12 via the pipe 33k and the heat pump forward pipe 4. The discharge port of the first circulation pump 22 is also connected to the C port of the switching valve 25 via the pipe 33l. The D port of the switching valve 25 is connected to the low-temperature water return port 21c of the hot water tank 21 via the pipe 33m. The G port of the switching valve 26 is connected to the high-temperature water inlet / outlet 21d via the pipe 33n and the pipe 33o. The high-temperature water inlet 21d is connected to the hot water mixing valve 29 and the bath mixing valve 30 via a pipe 33o and a pipe (high-temperature pipe) 33p. The H port of the switching valve 26 is connected to the reheating return port 21g via a pipe 33q.

[0026] An outlet of the hot water mixing valve 29 is connected via a pipe (hot water pipe) 33r to a hot water tap 35. A faucet (not shown) such as a shower or a faucet for use by a user is connected to the hot water tap 35.

[0027] The outlet of the bath mixing valve 30 is connected to the bath heat exchanger 24 via a pipe (bath pipe) 33s. A flow rate sensor 36 for detecting the flow rate of bath water flowing into the bathtub 6 and an electromagnetic valve 37 are interposed in the pipe 33s. One end of the bath outflow pipe 33t is connected to the pipe 33s downstream of the electromagnetic valve 37, and the other end of the bath outflow pipe 33t is connected to the bathtub 6. A bath outflow temperature sensor 38 for detecting the temperature of bath water flowing out from the bath heat exchanger 24 is attached to the bath outflow pipe 33t. The bathtub 6 is connected to the secondary side of the bath heat exchanger 24 via the bath return pipe 33u. A bath return temperature sensor 39 for detecting the temperature of bath water flowing out from the bathtub 6 is attached to the bath return pipe 33u. In addition to the second circulation pump 23, a water level sensor 40 for detecting the water level in the bathtub 6 and a flow switch 41 for detecting the circulation of water in the bath return pipe 33u are interposed in the bath return pipe 33u.

[0028] The tank unit 2 further includes a control device 50. The control device 50 controls the operation of various valves, pumps, and the like included in the electrically connected heat pump unit 1 and tank unit 2. In the present disclosure, a single control device 50 is provided in the tank unit 2, but a single control device may be provided in the heat pump unit 1. Also, a control device may be provided in both the heat pump unit 1 and the tank unit 2. In this case, the multiple control devices can be configured to work together.

[0029] The remote control device 3 has a function of accepting user operations related to operation commands and changes in set values. By operating the remote control device 3, the user can remotely control the heat pump water heater HD and perform various settings and changes related to operation commands and temperature. The remote control device 3 is an example of an operation terminal or a user interface device. Two-way communication is possible between the remote control device 3 and the control device 50 by wired communication or wireless communication. The remote control device 3 includes a display unit 3a that displays information such as the state of the heat pump water heater HD, and an operation unit 3b such as a switch or button operated by the user. The operation unit 3b includes a stop button that stops the heating operation. The remote control device 3 may include a touch screen having the functions of both the display unit 3a and the operation unit 3b. Although not shown, the remote control device 3 may further include a speaker, a microphone, etc. The remote control device 3 can be installed in a bathroom. The heat pump water heater HD may include multiple remote control devices 3.

[0030] The display unit 3a of the remote control device 3 has a function as a notification means for notifying a user by displaying information, such as displaying meridian time information as meridian time described later. The remote control device 3 may notify a user of information by voice, sound, or the like. In addition to the remote control device 3, or instead of the remote control device 3, a mobile terminal such as a smartphone, a smart speaker, a television, or other device may be configured to be used as a user interface and notification means. The control device 50, the remote control device 3, and other user interfaces may be capable of communicating with each other via the Internet or a local area network. The operation unit 3b of the remote control device 3 has a function as a region information input means and a calendar information input means described later.

[0031] The control device 50 receives inputs such as outputs from various sensors equipped in the heat pump water heater HD and information on the user's operation of the remote control device 3. The control device 50 controls the operations of the heat pump unit 1 and the tank unit 2 based on this input information. For example, the control device 50 controls the operating states of the compressor 11, the first circulating pump 22, and the second circulating pump 23, the opening degree of the expansion valve 13, and the flow direction or switching position of the switching valves 25, 26, 27, and 28, and the mixing valves 29 and 30. The control device 50 also executes a boiling operation, a reheating operation, and the like, as described below.

[0032] The control device 50 determines the amount of remaining hot water or the amount of heat stored in the hot water storage tank 21 based on the output of the hot water storage temperature sensors 211, 212, and 213, and controls the start and stop of a boiling operation by the heat pump unit 1 to boil the hot water stored in the hot water storage tank 21 according to the determined amount of remaining hot water or the amount of heat stored. In the boiling operation, low-temperature water flowing out from the bottom of the hot water storage tank 21 is guided to the heat pump unit 1 via the heat pump forward piping 4, and is heated in the water-refrigerant heat exchanger 12 to become high-temperature water. This high-temperature water flows into the hot water storage tank 21 from the hot water inlet outlet 21e at the top of the hot water storage tank 21 via the heat pump return piping 5. By performing such a boiling operation, high-temperature water is stored from the upper part inside the hot water storage tank 21, and this high-temperature water layer gradually becomes thicker toward the bottom. The controller 50 ends the boiling operation when the amount of hot water or heat stored in the hot water tank 21 detected by the hot water temperature sensors 211, 212, 213 exceeds a predetermined amount. The detailed control of the boiling operation by the controller 50 will be described later.

[0033] The control device 50 controls the hot water supply mixing valve 29 to adjust the flow rate ratio between high-temperature water supplied from the hot water storage tank 21 through the high-temperature piping 33p and low-temperature water or medium-temperature water supplied from the piping 31d. This generates hot water at a set temperature set by the user using the remote control device 3. The hot water whose temperature has been adjusted by the hot water supply mixing valve 29 is supplied to a faucet (not shown) such as a shower or a faucet used by the user via the hot water supply piping 33r and the hot water tap 35.

[0034] The control device 50 controls the bath mixing valve 30 to adjust the flow rate ratio between high-temperature water supplied from the hot water storage tank 21 through the high-temperature pipe 33p and low-temperature water or medium-temperature water supplied from the pipe 31d. This produces hot water at the temperature set by the user using the remote control device 3. The hot water whose temperature has been adjusted by the bath mixing valve 30 is supplied to the bathtub 6.

[0035] The control device 50 determines the completion of filling the bathtub based on the information detected by the water level sensor 40 and the flow switch 41. This allows the amount of bath water in the bathtub 6 when filling is complete to be controlled so that it is equal to the amount of water set by the user on the remote control device 3.

[0036] The heat pump water heater HD may be capable of automatic bath operation. When automatic bath operation is set by the remote control device 3, the control device 50 heats, cools, adds hot water, or adds cold water as necessary after the bathtub 6 is filled so that the temperature and amount of bath water in the bathtub 6 are maintained at the temperature and amount set by the remote control device 3.

[0037] Fig. 2 is a schematic cross-sectional view of a building 100 in which a heat pump water heater HD according to the present embodiment is installed. As shown in Fig. 2, the building 100 is equipped with a heat pump unit 1, a tank unit 2, a remote control device 3, a solar power generation device 60, a distribution board 61, a power distribution control device 62, and the like. The building 100 may be used as, for example, a residence, a store, a facility, an office, or the like.

[0038] The photovoltaic power generation device 60 includes a solar cell that receives sunlight and generates power, and performs photovoltaic power generation. The photovoltaic power generation device 60 is connected to the input side of a distribution board 61 via a wiring 64, and transmits the generated power to the distribution board 61. The distribution board 61 is configured as a power supply circuit that inputs, outputs, and distributes power, and is connected to a power system of a power company via a power line 63. The distribution board 61 purchases power from the power company via the power line 63, and sells power to the power company via the power line 63. The tank unit 2 is connected to the output side of the distribution board 61 via a wiring 65. The heat pump water heater operates by receiving power supplied from the distribution board 61 via the wiring 65. In the following description, electric equipment (not shown) that receives power supply from the distribution board 61 other than the heat pump water heater is referred to as "other electric equipment". The other electric equipment may include at least one of an air conditioner, a lighting device, a refrigerator, a washing machine, and an electric car, for example. The other electric devices are connected to the output side of the distribution board 61 via wiring (not shown). In the following description, the power consumption of the heat pump water heater HD is referred to as "water heater power consumption", and the power consumption of electric devices other than the heat pump water heater HD is referred to as "other device power consumption" or "in-house power consumption".

[0039] The power distribution control device 62 is connected to the distribution board 61 via wiring 66. The power distribution control device 62 is also communicatively connected to the control device 50 of the heat pump water heater HD via wireless or wired communication. The power distribution control device 62 includes at least one memory and at least one processor. The power distribution control device 62 may be configured, for example, by an EMS (Energy Management System) controller or the like. The power distribution control device 62 has a function of acquiring information on the photovoltaic power generation device 60 and information on the heat pump water heater via the distribution board 61, a function of controlling the operating state of the distribution board 61, and a function of transmitting commands to the control device 50 of the heat pump water heater HD.

[0040] The information acquired by the power distribution control device 62 includes information on the amount of power generated by the solar power generation device 60 and information on the amount of hot water stored in the hot water storage tank 21. The power distribution control device 62 is provided with a selection switch 62a used for various operations.

[0041] The operation of the solar power generation device 60 will be described. The solar power generation device 60 generates electricity by receiving sunlight during the day. The electricity generated by sunlight is transmitted to the distribution board 61 via wiring 64. At this time, the distribution board 61 reverse-flows the electricity obtained by subtracting the total power consumption (=power consumption by the water heater + power consumption by other devices) from the power generated by the solar power generation device 60 via power line 63, and sells the electricity to the power company.

[0042] When the solar power generation device 60 is not generating power, the distribution board 61 supplies power provided from the power company via the power line 63 to the heat pump water heater HD. The operation of the distribution board 61 may be performed based on commands from a control circuit or the like mounted on the distribution board 61, or based on commands from the power distribution control device 62.

[0043] The heat pump water heater HD can perform a boiling operation using surplus power, which is power generated by the solar power generation device 60 excluding power consumed by other devices.

[0044] Hereinafter, the control of the boiling operation by the control device 50, which is a characteristic feature of the present disclosure, will be described.

[0045] Regarding electricity rates, since 2021, due to the decline in the purchase price of surplus PV power and the increase in nighttime electricity rates, there are an increasing number of cases where self-consumption is more advantageous than selling power, even for newly built homes. Therefore, from February 2022, Tokyo Electric Power Company has started accepting applications for "Kurashijozu", a rate plan for solar self-consumption promotion type water heaters, and several companies have released solar self-consumption promotion type water heaters, including the heat pump water heater HD according to this embodiment. For this reason, it is assumed that users of the heat pump water heater HD will subscribe to "Kurashijozu". The electricity rate for "Kurashijozu" is 20.8 yen / kWh for both day and night regardless of the time of day, which is higher than the unit price of 17 yen / kWh for selling power in 2022. For this reason, even with "Kurashijozu", there is an advantage to self-consumption of solar power rather than heating it with purchased power. In addition, even without utilizing surplus electricity, performing heating operation during the day when the outside temperature is high results in a higher COP and reduces heat radiation, making it more efficient as a heat pump water heater HD.

[0046] When performing the water heating operation, the control device 50 acquires the amount of water to be heated [L] during the preset daytime period DH using the water heating amount acquisition means 51. The amount of water to be heated [L] may be determined or calculated based on the learning results of water previously used by the user, or, if the device has specifications that fix the amount of water to be heated, a fixed amount [L] that is not based on the learning results may be acquired.

[0047] Here, the daytime period DH refers to a period set as the main heating period in, for example, the control device 50 of the heat pump water heater HD. As a default value of the daytime period DH, the main heating period stipulated to promote the use of surplus electricity generated by photovoltaic power generation, specifically, the main heating period stipulated in JRA (Japan Refrigeration and Air Conditioning Industry Association Standard) 4085:2022, can be set in advance from 9:00 to 16:00. That is, the daytime period DH can be made to match the main heating period. As a result, the default setting value of the daytime period DH at the time of shipment from the factory of the heat pump water heater HD is from 9:00 to 16:00. In this case, the start time DHs of the daytime period DH is 9:00, and the end time DHe is 16:00.

[0048] Based on the acquired amount of water to be boiled [L], the control device 50 calculates the boiling time TB [min] for performing the boiling operation by the boiling time calculation means 52. The boiling time TB [min] in the main boiling time zone DH can be calculated, for example, by the following formula (1).

[0049] Heating time TB [min] = amount of hot water heated during main heating period DH [L] × (hot water temperature [℃] – water temperature [℃]) / 860 [kcal / kWh] / heating capacity of heat pump unit 1 [kW] × 60 [min] (1)

[0050] As shown in FIG. 3(a), the control device 50 controls the start timing of the boiling operation so that the calculated middle time TBc of the boiling time TB coincides with the middle time DHc of the daytime period DH. The start timing of the boiling operation corresponds to the start time TBs of the boiling time TB (hereinafter referred to as the "boiling start time"). The boiling start time TBs can be calculated, for example, by the following formula (2). The middle time DHc of the main boiling period DH is the time halfway between the start time DHs and the end time (target end time) DHe of the main boiling period DH.

[0051] Boiling start time TBs = Midpoint time DHc of main boiling time period DH - (Boiling time TB in main boiling time period DH / 2) (2)

[0052] Generally, the amount of sunlight peaks around noon, but if the start timing of the water heating operation is controlled as described above, the water heating operation is performed at a timing such that the middle time TBc of the water heating time TB is close to noon. In this way, as shown in Figure 4(a), the power consumption of the water heater can be covered by surplus power generated by solar power generation. On the other hand, if the water heating starts at the start of the daytime period as shown in Figure 4(b), or if the water heating is completed at the end of the daytime period as shown in Figure 4(c), the blackened area Pb in each figure cannot be covered by surplus power.

[0053] In addition, the "Kurashijozu" plan that users of heat pump water heaters subscribe to has a flat rate system for day and night. For this reason, unlike the control for minimizing costs in the rate plan for night-time storage devices, where the daytime rate is higher than the nighttime, there is no need to implement complex control that takes into account the weather and the electricity rate, such as stopping heating when it rains and restarting heating when it is sunny, and there is no need to start and stop unnecessary equipment.

[0054] Therefore, according to this embodiment, it is possible to increase the effectiveness of utilizing surplus electricity generated by solar power generation. Also, since it is not necessary to take the weather into consideration, it is not necessary to introduce an information collection unit for acquiring weather information, so the initial cost and running cost borne by the user can be minimized compared to the conventional hot water heater for self-consumption of solar power generation.

[0055] The main heating time for solar self-consumption promotion water heaters is from 9:00 to 16:00, which is defined as the time when surplus electricity from solar power generation is expected, and is specified based on the surplus electricity data from solar power generation measured by Tokyo Electric Power Company Holdings, Inc. at 197 locations within the jurisdiction of Tokyo Electric Power Company from November 2018 to May 31, 2020. The midpoint of the main heating time is 12:30. The time of meridian, which is the peak of solar radiation, differs depending on the region and season, but in Tokyo it is 11:44 ± 15 minutes, so although there is a slight difference from 12:30, which is the midpoint of the daytime hours specified by heat pump water heaters HD, the center of the heating start time can be set near meridian, so if 12:30 is set as the midpoint of heating, the amount of surplus utilization can be increased compared to when the heating start time is set to the start time of the daytime hours.

[0056] In addition, by aligning the daytime DH time period with the main boiling time period specified in JRA4085:2022, the utilization of surplus electricity can be maximized.

[0057] In addition, the control device 50 can calculate the amount of hot water to be heated [L] during the main heating period using the following formula (3). The hot water supply and insulation load corresponds to the amount of heat used for hot water supply learned for each hour in the past. The amount of heat dissipation is the amount of heat dissipated from the hot water stored in the hot water storage tank 21.

[0058] Amount of hot water heated during the main heating period [L] = Hot water insulation load based on learning results × amount of heat radiation × ratio of amount of hot water heated during the main heating period (3)

[0059] The control device 50 calculates the amount of hot water to be heated [L] in the above equation (3) with the heating amount ratio set to 0.5, and by controlling the start timing of the heating operation in the above-mentioned manner, a heat pump water heater HD can be provided that meets the requirement of consuming more than 50% of the daily power consumption between 9:00 and 16:00 under the winter hot water heating and insulation mode and winter hot water heating mode test conditions specified in JRA4085:2022.

[0060] The control device 50 can be set so that the heating heat ratio during the main heating time period in the above-mentioned winter hot water supply and insulation mode and winter hot water supply mode test conditions is 50% or more in the winter hot water supply and insulation mode and winter hot water supply mode test conditions.

[0061] In order to satisfy the requirement that the power consumption in a day is 50% or more in the time period from 9:00 to 16:00 in the above-mentioned winter hot water supply and insulation mode and winter hot water supply mode test conditions, the control device 50 limits the start time TBs and the end time TBe of the water heating that can be set by the user so that the heat amount of the water heating in the winter hot water supply and insulation mode and winter hot water supply mode test conditions is 50% or more even when the water heating time TB is changed by the user. For example, in order to heat 50% or more of the power consumption in a day in the time period from 9:00 to 16:00 in the winter hot water supply and insulation mode conditions, if it is assumed that, for example, 4 hours are required, taking into account the amount of heat radiation, the start time TBs and the end time TBe of the water heating can be obtained as follows.

[0062] If you want to boil water for four hours around 12:30, which is the midpoint of the daytime DH, The start time of boiling, TBs, is 12:30 - boiling time 4 hours ÷ 2 = 10:30. The end time of boiling TBe is 12:30 + boiling time 4 hours ÷ 2 = 14:30. In this case, the boiling start time TBs can be set before 10:30, and the boiling end time TBe can be set after 14:30. Furthermore, as in the case of moving the boiling start time forward as shown in Figure 3(b), the boiling start time TBs is set within the range calculated by the following formula (4) so ​​that the four-hour boiling time TB does not deviate from the range of 9:00 to 16:00. (Start time + End time) / 2-(Boiling time during main boiling period) / 2=9:00 (4)

[0063] By transforming the above equation (4), the following equation (5) is obtained. For a model with a boiling time TB of 4 hours, the boiling start time TBs can be set within the range of 7:30 to 10:30. Start time = (9:00 + boiling time during main boiling period TB÷2) x 2 - end time = (9:00 + 4 hours / 2) x 2 - 14:30 =7:30...(5)

[0064] Similarly, in the case of postponing the boiling as shown in Figure 3(c), the boiling end time TBe is set within the range obtained by the following equation (6) so that the four-hour boiling does not deviate from the range of 9:00 to 16:00. (Start time + End time) ÷ 2 + (Boiling time during main boiling period) ÷ 2 = 16:00 (6)

[0065] By transforming the above equation (6), the following equation (7) is obtained, and for a model with a boiling time of 4 hours, the boiling end time TBe can be set within the range of 2:30 p.m. to 5:30 p.m. End time = (16:00 - boiling time during main boiling period ÷ 2) x 2 - start time = (4pm - 4 hours ÷ 2) x 2 - 10:30am =5:30pm...(7)

[0066] In addition, under the winter hot water supply and insulation mode conditions, in order to heat more than 50% of the heat required for the day between 9:00 and 16:00, the heating start time TBs and the heating end time TBe can be calculated using the above equations (4), (5), (6), and (7) based on the heating time TB calculated taking into account the amount of heat dissipation.

[0067] However, the daytime hours DH are low-cost hours during which the hourly rate for electricity used by the heat pump water heater HD is lower than other hours, and the main boiling time period, which is specified to promote the use of surplus electricity generated by solar power generation, may not match the low-cost time period. In this case, the control means 50 changes the boiling time TB within the time period where the low-cost time period and the main boiling time period overlap, and around the middle of the low-cost time period, so that the heat pump water heater HD uses 50% or more of the amount of electricity it uses in a day.

[0068] Here, the solar self-consumption promotion type water heater is stipulated in JRA4085:2022 that the daytime power consumption ratio must be 50% or more under the conditions of the winter hot water heating and insulation mode and winter hot water mode test during the time period from 9:00 to 16:00, which is defined as the main heating time, but the user can change the heating start and end times at his / her discretion as long as the stipulated requirements are met. The intention is to assume that a time period other than 9:00 to 16:00, which is the main heating time defined in the solar self-consumption promotion type water heater (for example, 10:00 to 17:00, etc.) is set as the daytime time period in the newly implemented rate menu, and by configuring the start and end times of the heating time to be changeable at the user's discretion, it is possible to provide a heat pump water heater HD that satisfies the requirements stipulated in JRA4085:2022 while allowing the daytime time period to be changed. In addition, since the time of noon varies depending on the season and region, by allowing users to change the daytime hours settings at their own discretion, it is expected that the utilization of surplus electricity will be expanded while satisfying the provisions of JRA4085:2022, even if the main heating time period for the region and power menu changes.

[0069] Furthermore, if they do not match as described above, the control device 50 may change the boiling time so that 50% or more of the heat required for boiling in one day is boiled during the time period in which the low-cost time period and the main boiling time period overlap, and mainly during the middle time period of the low-cost time period. This is expected to lead to increased utilization of surplus electricity, as there is an almost one-to-one relationship between the heat required for boiling and the amount of power consumed.

[0070] Moreover, it is preferable that the heat pump water heater HD further includes a noon time input means for inputting the noon time. The noon time input means can be configured, for example, by the operation unit 3b of the remote control device 3. The control device 50 controls the start timing of the boiling operation so that the midpoint time of the boiling time coincides with the noon time inputted by the noon time input means. By having the user input the noon time, it is possible to reliably ensure that the noon time and the midpoint time of the main boiling time period coincide. Since the boiling time is difficult for the user to grasp, convenience can be improved by directly inputting the noon time that the user can grasp and changing the setting on the heat pump water heater HD, thereby improving convenience.

[0071] In this case, the input of the meridian time by the user can be assisted by further providing a notification means for notifying the user of the meridian time of the region where the heat pump water heater HD is installed based on the electric power company's regional information. The notification means can be configured, for example, by the display unit 3a of the remote control device 3. Furthermore, since the meridian time differs from region to region, it is possible to notify the user to whom the regional information is linked based on the settings of the electric power company, etc. At this time, since the meridian time differs depending on the region and season, the optimal meridian time can be notified. Moreover, since there is no need to purchase a separate information collection unit for acquiring weather information, etc., costs for the user are not increased.

[0072] In this case, the boiling start time TBs can be calculated using the following formula (8). In other words, whereas the middle time TBc of the boiling time TB was controlled to coincide with the middle time DHc of the main boiling time period DH, the middle time DHc is replaced with the meridian time. Boiling start time TBs = meridian time - (boiling time during main boiling period / 2) (8)

[0073] The control device 50 may also notify the user of the recommended boiling start time TBs and boiling end time TBe together with the noon time. The notification method may be a display on the display unit 3a of the remote control device 3 or a sound.

[0074] The heat pump water heater HD may further include a region information input means for inputting region information where the heat pump water heater HD is installed, and a calendar information input means for inputting calendar information. The region information input means and the calendar information input means may be constituted, for example, by the operation unit 3b of the remote control device 3. The control device 50 may further include a notification means for extracting noon time information corresponding to the region information input by the region information input means and the calendar information input by the calendar information input means from the noon time information pre-stored in the heat pump water heater HD, and notifying the user of the extracted noon time information as noon.

[0075] A data map of the noon time for each region and season is stored as internal data in the control device 50 of the heat pump water heater HD, and the user is allowed to select an electricity rate plan and an electric power company using the remote control device 3. The electricity rate plan and the electric power company may be linked to regional information, and the noon time for each region may be selected by the user's selection. The control device 50 may be configured to determine the season based on calendar information it has, and to obtain the noon time for each season by referring to the data map.

[0076] The heat pump water heater HD may also include a noon time acquisition means for acquiring the noon time of the region where the heat pump water heater HD is installed based on the regional information of the electric power company. The noon time acquisition means may be configured, for example, as the control device 50. The control device 50 may change the noon time of the daytime period DHc to the noon time if the difference between the acquired noon time and the midpoint time DHc of the daytime period DH is equal to or greater than a predetermined time set in advance. In this case, the control device 50 may be configured to acquire the noon time for each region and season through a cloud (not shown) that can communicate with the control device 50. For example, the noon time is 12:00, the midpoint time DHc of the daytime period DH is 12:30, and the difference between them is 30 minutes. If 30 minutes is equal to or greater than the preset time, the midpoint time DHc is changed to the noon time. This allows the boiling time TB to be appropriately adjusted even if the midpoint time DHc of the daytime period DH is significantly different from the noon time. The control device 50 may also include a notification setting means for setting in advance to notify whether or not to change to the noon time. The notification setting means can be configured, for example, by the operation unit 3b of the remote control device 3. In this case, for example, a user who receives a notification by display on the display unit 3a of the remote control device 3 or by audio can select whether or not to advance the boiling start time TBs by 30 minutes, improving user convenience.

[0077] The heat pump water heater HD may also include a pause setting means capable of pausing (stopping) the heating operation during the daytime hours DH. The pause setting means may be configured, for example, by the operation unit 3b of the remote control device 3. For example, a part of the operation unit 3b may be configured as a button for pausing and canceling the heating operation. This allows the control device 50, which receives the operation signal in response to the operation of the operation unit 3b by the user, to pause and cancel the heating operation. By pausing heating from 7:00 to midnight (heating for one day), including heating during the daytime hours, it becomes possible to prioritize selling electricity on days when hot water is not used on that day, improving the convenience of the user. The control device 50 may also continue pausing the heating operation until the user performs an operation to cancel the pause setting.

[0078] Here, in the conventional night-storage type water heater, it was not possible to stop heating during the main heating time period. This is because the night-storage type water heater needs to heat the hot water to be used on the day using the time period from the night of the previous day to the morning of the day, and if heating during the main heating time is stopped in the middle of the night, the amount of hot water stored the next day will be reduced, so stopping heating during the main heating time may cause problems with the user's experience. In contrast, a solar self-consumption promotion type water heater such as the heat pump water heater HD disclosed herein is a water heater that has the property of "heating the hot water to be used on the day during the day (9:00 to 16:00) on the day," and if there is no use of hot water on the day, even if heating during the main heating time period is stopped, the amount of hot water required the next day will be heated during the day, so there is no impact on the user's experience the next day. The hot water shortage resistance is low at midnight when the heating pause setting is automatically released, or at the pinpoint of the timing when the user arbitrarily releases it. However, purchasers of solar powered self-consumption promotion water heaters understand that they are water heaters that heat water during the day to utilize surplus solar power, and they likely set the water heating suspension setting based on the assumption that no hot water will be used on the day, so the reduction in resistance to pinpoint hot water shortages when the setting is cancelled is within the range that users can anticipate and does not impair the usability.For this reason, this function has the advantage of being a function that suspends water heating and prioritizes electricity sales.

[0079] The heat pump water heater HD may also include a heating capacity setting means capable of arbitrarily setting the heating capacity of the heat pump unit 1. The heating capacity setting means may be configured, for example, by the operation unit 3b of the remote control device 3. For example, settings such as capacity save 1 and capacity save 2 may be provided in advance, and when the user operates the operation unit 3b to set capacity save 1, the heating capacity may be changed to, for example, 10% lower than the rated heating capacity, and when capacity save 2 is set, the heating capacity may be changed to, for example, 20% lower than the rated heating capacity. If the heating capacity of the heat pump unit 1 can be arbitrarily set by the user, when there is a lot of power consumption other than the water heater HD during the day and it is desired to suppress the peak power, the power consumption can be suppressed by setting the heating capacity low, and the power peak can be suppressed. In particular, in the case of an actual metered electricity rate plan in which the annual basic fee is determined by the power consumption peak, there is an advantage for the user in suppressing the power consumption peak.

[0080] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be implemented in various modified forms without departing from the spirit of the present invention.

[0081] In the above embodiment, the remote control device 3 having the notification function and the information presentation function is provided in the bathroom, but it may be provided in a location near the bathroom, for example, at the entrance to the bathroom or in a dressing room, or in the kitchen. Also, instead of the remote control device 3, a mobile terminal such as a smartphone may be used.

[0082] In addition, among the features of the above-described embodiment, two or more features that can be combined may be combined. Various aspects of the present disclosure will be described below as supplementary notes.

[0083] (Appendix 1) A heat pump cycle for heating water; A hot water tank and A control device that controls a heating operation in which hot water heated by the heat pump cycle flows into the hot water storage tank; A heat pump water heater comprising: The control device acquires the amount of hot water to be heated during a predetermined daytime period, calculates the heating time for performing the heating operation based on the acquired amount of hot water to be heated, and controls the start timing of the heating operation so that the midpoint of the calculated heating time coincides with the midpoint between the start time and end time of the daytime period. (Appendix 2) The heat pump water heater according to claim 1, wherein the control device coincides with a main heating time period that is specified to promote utilization of surplus electricity generated by solar power generation. (Appendix 3) The heat pump water heater according to claim 1 or 2, wherein the control device controls the timing of the start of the heating operation so that the heat pump water heater consumes 50% or more of the amount of power consumption used in a day during the daytime hours. (Appendix 4) The heat pump water heater according to any one of claims 1 to 3, wherein the control device controls the start timing of the heating operation so that 50% or more of the daily heating heat is heated during the daytime hours. (Appendix 5) A heat pump water heater according to any one of Supplementary Note 1 to Supplementary Note 4, When the daytime hours are low-cost hours during which the hourly rate of electricity used by the heat pump water heater is lower than other hours, and the main boiling time period specified to promote the use of surplus electricity generated by solar power generation does not match the low-cost time period, The control device changes the boiling time of the heat pump water heater so that the heat pump water heater uses more than 50% of the amount of electricity it uses in a day during a period when the low-cost time period and the main boiling time period overlap, and around the middle of the low-cost time period. (Appendix 6) A heat pump water heater according to any one of Supplementary Note 1 to Supplementary Note 5, When the daytime hours are low-cost hours during which the hourly rate of electricity used by the heat pump water heater is lower than other hours, and the main boiling time period specified to promote the use of surplus electricity generated by solar power generation does not match the low-cost time period, The control device is a heat pump water heater that changes the boiling time so as to boil more than 50% of the daily boiling heat amount during the time period when the low-cost time period and the main boiling time period overlap, and mainly during the middle time period of the low-cost time period. (Appendix 7) A noon time input means for inputting a noon time is further provided, The heat pump water heater according to any one of appendices 1 to 6, wherein the control device controls the start timing of the boiling operation so that the intermediate time of the boiling time coincides with the noon time inputted by the noon time input means. (Appendix 8) 8. The heat pump water heater according to claim 7, further comprising a notification means for notifying a user of the meridian time in the area in which the heat pump water heater is installed, based on regional information of an electric power company. (Appendix 9) A region information input means for inputting region information in which the heat pump water heater is installed; A calendar information input means for inputting calendar information, the control device extracts noon time information corresponding to the regional information input by the regional information input means and the calendar information input by the calendar information input means from noon time information pre-stored in the heat pump hot water heater; The heat pump water heater according to any one of appendix 1 to appendix 8, further comprising a notification means for notifying a user of the noon time information extracted by the control device as the noon time. (Appendix 10) a noon time acquisition means for acquiring the noon time of the region in which the heat pump water heater is installed based on regional information of an electric power company; The heat pump water heater according to any one of Appendices 1 to 9, wherein the control device changes the mid-time of the daytime hours to the noon time if the difference between the noon time acquired by the noon time acquisition means and the mid-time of the daytime hours is equal to or greater than a predetermined time. (Appendix 11) The heat pump water heater described in Appendix 10, wherein the control device is equipped with a notification setting means that is set in advance to notify whether or not to change the midpoint time of the daytime hours to the meridian time if the difference between the meridian time and the midpoint time of the daytime hours is equal to or greater than a predetermined time. (Appendix 12) 12. The heat pump water heater according to any one of claims 1 to 11, further comprising a pause setting means capable of pausing the heating operation during the daytime hours. (Appendix 13) 13. The heat pump water heater according to any one of claims 1 to 12, comprising a heat pump unit having the heat pump cycle, wherein the heating capacity of the heat pump unit can be set arbitrarily. [Explanation of symbols]

[0084] HD...heat pump water heater, 1...heat pump unit, 2...tank unit, 3...remote control device, 3a...display unit, 3b...operation unit, 4...heat pump forward piping, 5...heat pump return piping, 6...bathtub, 10...refrigerant circuit (heat pump cycle), 11...compressor, 12...water-refrigerant heat exchanger, 13...expansion valve, 14...air heat exchanger, 15...refrigerant circulation piping, 21...hot water tank, 21a... Water inlet, 21b...water outlet, 21c...water inlet, 21d...hot water outlet, 21e...hot water outlet, 21f...medium temperature water inlet, 21g...medium temperature water inlet, 211, 212, 213...hot water temperature sensor, 22...first circulation pump, 23...second circulation pump, 24...bath heat exchanger, 25, 26, 27, 28...switching valve, 29...hot water supply mixing valve, 30...bath mixing valve, 31a, 31b, 31c, 31 d...piping, 32...pressure reducing valve, 33a, 33b, 33c, 33d, 33e, 33f, 33g, 33h, 33i, 33j, 33k, 33l, 33m, 33n, 33o, 33p, 33q, 33r, 33s, 33t, 33u...piping, 34...check valve, 35...hot water tap, 36...flow sensor, 37...solenoid valve, 38...bath temperature sensor, 39...bath temperature sensor, 40...water level sensor, 41...f Low switch, 50...control device, 51...means for acquiring amount of water to be heated, 52...means for calculating heating time, 60...photovoltaic power generation device, 61...distribution board, 62...power distribution control device, 62a...selection switch, 62b...display unit, 63...power line, 64, 65, 66...wiring, 100...building, DH...daytime period, DHc...middle time of daytime period DH, TB...heating time, TBc...middle time of heating time TB

Claims

1. A heat pump cycle for heating water; A hot water tank and A control device that controls a heating operation in which hot water heated by the heat pump cycle flows into the hot water storage tank; A heat pump water heater comprising: The control device acquires the amount of hot water to be heated during a predetermined daytime period, calculates the heating time for performing the heating operation based on the acquired amount of hot water to be heated, and controls the start timing of the heating operation so that the midpoint of the calculated heating time coincides with the midpoint between the start time and end time of the daytime period.

2. The heat pump water heater according to claim 1 , wherein the control device matches the daytime hours with a main heating time period that is defined to promote utilization of surplus electricity generated by photovoltaic power generation.

3. The heat pump water heater according to claim 1 , wherein the control device controls the start timing of the boiling operation so that 50% or more of the amount of power consumption used by the heat pump water heater in a day is consumed during the daytime hours.

4. The heat pump water heater according to claim 1 , wherein the control device controls a start timing of the water heating operation so that 50% or more of a daily amount of heat to be heated is heated during the daytime hours.

5. The heat pump water heater according to claim 1, When the daytime hours are low-cost hours during which the hourly rate of electricity used by the heat pump water heater is lower than other hours, and the main boiling time period specified to promote the use of surplus electricity generated by solar power generation does not match the low-cost time period, The control device changes the boiling time of the heat pump water heater so that the heat pump water heater uses more than 50% of the amount of power consumption it uses in a day during a time period when the low-cost time period and the main boiling time period overlap, and centered around the middle of the low-cost time period.

6. The heat pump water heater according to claim 1, When the daytime hours are low-cost hours during which the hourly rate of electricity used by the heat pump water heater is lower than other hours, and the main boiling time period specified to promote the use of surplus electricity generated by solar power generation does not match the low-cost time period, The control device changes the boiling time of the heat pump water heater so that 50% or more of the heat required for boiling in a day is boiled during a time period in which the low-cost time period and the main boiling time period overlap, and centered around the middle time of the low-cost time period.

7. A noon time input means for inputting a noon time is further provided, 2. The heat pump water heater according to claim 1, wherein the control device controls a start timing of the boiling operation so that the intermediate time of the boiling time coincides with the noon time inputted by the noon time inputting means.

8. The heat pump water heater according to claim 7, further comprising a notification means for notifying a user of a noon time in a region where the heat pump water heater is installed, based on regional information of an electric power company.

9. A region information input means for inputting region information in which the heat pump water heater is installed; A calendar information input means for inputting calendar information, the control device extracts noon time information corresponding to the regional information input by the regional information input means and the calendar information input by the calendar information input means from noon time information pre-stored in the heat pump hot water heater; The heat pump water heater according to claim 1 , further comprising a notification unit that notifies a user of the meridian time information extracted by the control device as the meridian time.

10. a noon time acquisition means for acquiring the noon time of the region in which the heat pump water heater is installed based on regional information of an electric power company; The heat pump water heater of claim 1, wherein the control device changes the mid-time of the daytime period to the noon time if the difference between the noon time acquired by the noon time acquisition means and the mid-time of the daytime period is equal to or greater than a predetermined time.

11. The heat pump water heater of claim 10, wherein the control device is provided with a notification setting means for presetting a notification as to whether or not to change the midpoint time of the daytime period to the meridian time if the difference between the meridian time and the midpoint time of the daytime period is equal to or greater than a predetermined time.

12. The heat pump water heater according to claim 1 , further comprising a pause setting unit capable of pausing the heating operation during the daytime hours.

13. The heat pump water heater according to claim 1 , further comprising a heat pump unit having the heat pump cycle, the heating capacity of the heat pump unit being able to be set arbitrarily.

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