JP2023102870A - Hot water storage type water heater - Google Patents

Abstract

To provide a hot water storage type water heater which can effectively utilize surplus power.SOLUTION: In a hot water storage type water heater 100 which is connected to a photovoltaic power generation device 200, a control device 4 can perform a standard heating boiling operation for operating a heat pump unit 1 at a first heating capacity H1, and operating a circulation pump 22 at a first rotation number N1, and a high-heating boiling operation for operating the heat pump unit 1 at a second heating capacity H2 which is higher than the first heating capacity H1, and operating the circulation pump 22 at a second rotation number N2 which is higher than the first rotation number N1, and when the surplus power of the photovoltaic power generation device 200 is larger than set power P1 which is set in advance, the control device also performs the high-heating boiling operation.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a storage hot water heater.

2. Description of the Related Art Some conventional hot water storage type water heaters perform a boiling-up operation in which hot water in a hot water storage tank is heated using power generated by an in-house power generator in addition to power supplied from a commercial power source. As such a hot water storage type water heater, for example, Patent Document 1 discloses that, when the electric power generated by a private electric power generator is larger than the electric power consumed in the home by a predetermined value or more, that is, when surplus electric power is generated, the surplus electric power is consumed by performing a boiling-up operation with the surplus electric power.

JP 2004-194485 A

However, in the hot water storage type water heater of Patent Document 1, depending on the amount of surplus power, even if the boiling operation is performed, surplus power may not be used effectively.

The present disclosure has been made to solve the above-described problems, and an object thereof is to provide a hot water storage type water heater that can effectively utilize surplus electric power.

A storage-type water heater according to the present disclosure is a storage-type water heater connected to a power generator that uses renewable energy, and includes a heating device that heats water, a hot-water storage tank that stores water heated by the heating device, a circulation pump that sends water in the hot-water storage tank to the heating device, and a control device that controls the operation of the heating device and the circulation pump to heat the water in the hot-water storage tank. A standard heating and boiling operation in which the operation is performed at the first rotation speed, and a high heating and boiling operation in which the heating device is operated at a second heating capability higher than the first heating capability and the circulation pump is operated at a second rotation speed higher than the first rotation speed can be performed, and the high heating and boiling operation is performed when the surplus power of the power generation device is larger than the preset power.

According to the hot water storage type water heater according to the present disclosure, when the surplus power of the power generation device is greater than the preset power, the high heating and boiling operation is performed in which the heating capacity of the heating device and the rotation speed of the circulation pump are higher than those of the standard heating and boiling operation. As a result, surplus power can be effectively used.

1 is a diagram showing the configuration of a hot water supply system according to Embodiment 1; FIG. 4 is a flow chart showing the operation of the hot water storage type water heater according to Embodiment 1. FIG. 4 is a diagram showing values of surplus electric power with respect to time in the hot water supply system according to Embodiment 1. FIG. FIG. 4 is a diagram showing values of the amount of heat given to water in a hot water storage tank with respect to time in (A) the hot water storage type hot water heater according to Embodiment 1 or (B) in a comparative example;

Embodiments of the present disclosure will be described below with reference to the drawings. It should be noted that specific numerical values and the like shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present disclosure unless otherwise specified. Also, in the following description, the notation of "hot water" and "water" can include cold water to hot water regardless of its temperature.

Embodiment 1.
FIG. 1 is a diagram showing the configuration of hot water supply system 1000 according to Embodiment 1. As shown in FIG. As shown in FIG. 1 , hot water supply system 1000 of Embodiment 1 includes hot water storage type hot water heater 100 , solar power generation device 200 , and power conditioner 300 . Hot water supply system 1000 of Embodiment 1 is provided in a facility such as a residence.

Storage-type water heater 100 is powered by both power generated by photovoltaic power generation device 200 and power supplied from an external commercial power source (not shown) so as to be operable. A detailed configuration of hot water storage type water heater 100 will be described later.

The solar power generation device 200 is an example of a power generation device using renewable energy. In the present embodiment, an example of using the solar power generation device 200 as a power generation device using renewable energy will be described, but a power generation device using other renewable energy such as a wind power generation device and a hydraulic power generation device may be used.

The power conditioner 300 converts the DC power generated by the photovoltaic power generation device 200 into AC power and supplies it to the hot water storage type water heater 100 .

A detailed configuration of the hot water storage type water heater 100 will be described. A hot water storage type water heater 100 includes a heat pump unit 1 , a hot water storage unit 2 , a remote control device 3 and a control device 4 .

The heat pump unit 1 is an example of a heating device that heats hot water led from the hot water storage unit 2 . In this embodiment, an example using the heat pump unit 1 as the heating device will be described, but instead of the heat pump type heating device, for example, a fuel type or electric heater type heating device may be used.

The heat pump unit 1 includes a compressor 11 , a water-refrigerant heat exchanger 12 , an expansion valve 13 , an air heat exchanger 14 and refrigerant pipes 15 . A heat pump cycle is formed by annularly connecting the compressor 11 , the water-refrigerant heat exchanger 12 , the expansion valve 13 , and the air heat exchanger 14 by the refrigerant pipe 15 . The heat pump unit 1 heats hot water by exchanging heat between the high-temperature refrigerant compressed by the compressor 11 and the hot water led from the hot water storage unit 2 in the water-refrigerant heat exchanger 12 .

The heat pump unit 1 further comprises an inlet 16 , an outlet 17 , an inlet pipe 18 and an outlet pipe 19 .

The inflow pipe 18 connects the inflow port 16 and the water inlet of the water-refrigerant heat exchanger 12 . The outflow pipe 19 connects the water outlet of the water-refrigerant heat exchanger 12 and the outflow port 17 .

The hot water storage unit 2 includes a hot water storage tank 21, a circulation pump 22, a hot water mixing valve 23, an HP outlet port 24, an HP return port 25, a water supply port 26, a hot water supply port 27, thermistors 28a-28c, and various pipes 51-58.

The hot water storage tank 21 stores hot water heated by the heat pump unit 1 . In the hot water storage tank 21, temperature stratification is formed in which the upper side is high temperature and the lower side is low temperature due to the difference in water density depending on the temperature. For convenience of explanation, the hot water storage tank 21 will be referred to as an upper portion, an intermediate portion, and a lower portion in order from the upper side.

The hot water storage tank 21 is provided with a first thermistor 28a, a second thermistor 28b and a third thermistor 28c. The first thermistor 28 a is provided above the hot water storage tank 21 and detects the temperature of hot water in the upper portion of the hot water storage tank 21 . The second thermistor 28 b is provided in the middle portion of the hot water storage tank 21 and detects the temperature of hot water in the middle portion of the hot water storage tank 21 . The third thermistor 28 c is provided below the hot water storage tank 21 and detects the temperature of hot water in the lower portion of the hot water storage tank 21 . Each thermistor 28 a to 28 c is an in-tank temperature detection unit that detects the temperature of the water in the hot water storage tank 21 .

One end of a first outgoing pipe 51 is connected to the lower portion of the hot water storage tank 21 . The other end of the first going pipe 51 is connected to the HP going port 24 . One end of a second outgoing pipe 52 is connected to the HP outgoing port 24 . The other end of the second going pipe 52 is connected to the inlet 16 of the heat pump unit 1 . A circulation pump 22 is provided in the middle of the first going pipe 51 . The circulation pump 22 sends the hot water in the lower part of the hot water storage tank 21 to the heat pump unit 1 .

One end of the first return pipe 53 is connected to the outflow port 17 of the heat pump unit 1 . The other end of the first return pipe 53 is connected to the HP return port 25 of the hot water storage unit 2 . One end of a second return pipe 54 is connected to the HP return port 25 . The other end of the second return pipe 54 is connected to the top of the hot water storage tank 21 . One end of the first hot water supply pipe 55 is connected to the middle of the second return pipe 54 . The other end of the first hot water supply pipe 55 is connected to the hot water supply mixing valve 23 .

The hot water mixing valve 23 is a three-way valve and has a hot water side inlet 23a, a cold water side inlet 23b and an outlet 23c. A first hot water supply pipe 55 is connected to the hot water side inlet 23 a of the hot water mixing valve 23 . One end of a first water supply pipe 56 is connected to the water side inlet 23 b of the hot water supply mixing valve 23 . The other end of the first water supply pipe 56 is connected to the water supply port 26 . The water supply port 26 is connected to a water source such as tap water. One end of a second water supply pipe 57 is connected to the middle of the first water supply pipe 56 . The other end of the second water supply pipe 57 is connected to the lower portion of the hot water storage tank 21 . One end of a second hot water supply pipe 58 is connected to the outlet 23 c of the hot water mixing valve 23 . The other end of the second hot water supply pipe 58 is connected to the hot water supply port 27 . The hot water supply port 27 is connected to a hot water supply terminal such as a faucet, a shower, etc., which is a hot water supply load. The hot water mixing valve 23 adjusts the temperature of the water flowing out from the outlet 23c by adjusting the mixing ratio of the water flowing in from the hot water side inlet 23a and the water flowing in from the water side inlet 23b.

The remote control device 3 is an example of a user interface. The remote control device 3 is attached, for example, to a wall surface of a kitchen, living room, bathroom, or the like. Although not shown, the remote control device 3 has, for example, a display unit that displays information about the state of the storage-type hot water heater 100 and an operation unit that accepts user's operations regarding the storage-type hot water heater 100 . Note that a mobile information terminal such as a smart phone may have a function as a user interface.

Control device 4 is provided inside hot water storage unit 2 . Control device 4 is electrically connected to each device included in storage-type hot water heater 100 . Specifically, the control device 4 is electrically connected to the heat pump unit 1, the remote control device 3, the circulation pump 22, the hot water mixing valve 23 and the thermistors 28a to 28c. The control device 4 has, as its functions, a hot water storage amount comparison unit 41 , a target hot water storage amount setting unit 42 , a boiling condition determination unit 43 , a heating control unit 44 and a surplus power acquisition unit 45 .

The stored hot water amount comparison unit 41 compares the current stored hot water amount Q1 in the hot water storage tank 21 with the target stored hot water amount Q2. The current hot water storage amount Q1 in the hot water storage tank 21 is the amount of heat currently stored in the hot water storage tank 21, and is calculated using the temperature distribution in the hot water storage tank 21 obtained by the thermistors 28a to 28c. In other words, the stored hot water amount comparison unit 41 also has a function as a stored hot water amount detection unit that detects the amount of stored hot water in the hot water storage tank 21 . The target hot water amount Q2 is the amount of heat required to be stored in the hot water storage tank 21, and is set by a target hot water amount setting unit 42, which will be described later.

The target hot water amount setting unit 42 sets the target hot water amount Q2. The target stored hot water amount setting unit 42 may set the target stored hot water amount Q2 to a predetermined value, or may set different values for each day or time period based on, for example, hot water usage records for each time period, hot water usage records for the last few days, season, temperature, and the like.

The boiling condition determination unit 43 determines the heating capacity of the heat pump unit 1 and the rotation speed of the circulation pump 22 in the boiling operation. The boiling operation is an operation in which the water in the hot water storage tank 21 is heated by the heat pump unit 1 and returned to the hot water storage tank 21 . Also, the heating capacity of the heat pump unit 1 is represented by the amount of heat given to water per unit time.

The boiling condition determining unit 43 has standard heating capacity and high heating capacity as boiling conditions. The standard heating capacity is a boiling-up condition in which the heating capacity of the heat pump unit 1 is the first heating capacity H1 and the rotation speed of the circulation pump 22 is the first rotation speed N1. The high heating capacity is a boiling-up condition in which the heating capacity of the heat pump unit 1 is the second heating capacity H2 and the rotation speed of the circulation pump 22 is the second rotation speed N2.

Here, the second heating capacity H2 is higher than the first heating capacity H1, and the second rotation speed N2 is higher than the first rotation speed N1. The first heating capacity H1 is a heating capacity for heating water to, for example, 65° C. in order to suppress the propagation of bacteria such as Legionella. Further, when the first heating capacity H1 is a heating capacity for heating water to a temperature of 65°C, the second heating capacity H2 is a heating capacity for heating water to a temperature higher than 65°C. The high heating capacity is a boiling condition in which the temperature of all the water in the hot water storage tank 21 is raised to a sterilizable temperature, e.g., 65° C. or higher, which can suppress the propagation of bacteria such as Legionella by raising the temperature of the water heated by the heat pump unit 1 while stirring the water in the hot water storage tank 21 by increasing the rotation speed of the circulation pump 22 compared to the standard heating capacity.

The boiling condition determination unit 43 may determine the second heating capacity H2 and the second rotation speed N2 to be predetermined values, or may be determined to values according to the amount of surplus power of the photovoltaic power generation device 200. For example, when the amount of surplus power is large, the values of the second heating capacity H2 and the second rotation speed N2 may be made larger than when the amount of surplus power is small.

Further, the boiling condition determination unit 43 may determine the second heating capacity H2 and the second rotation speed N2 according to the difference between the current hot water amount Q1 in the hot water storage tank 21 and the target hot water amount Q2. For example, when the difference between the current hot water amount Q1 and the target hot water amount Q2 is large, the values of the second heating capacity H2 and the second rotation speed N2 may be made larger than when the difference is small.

Further, the boiling condition determination unit 43 may determine the second heating capacity H2 and the second rotation speed N2 based on both the amount of surplus power of the solar power generation device 200 and the difference between the current hot water amount Q1 and the target hot water amount Q2 in the hot water storage tank 21.

The heating control unit 44 performs the boiling operation by controlling the operations of the heat pump unit 1 and the circulation pump 22 under the boiling conditions determined by the boiling condition determination unit 43 . The boiling-up operation performed with the standard heating capacity is called the standard heating boiling-up operation, and the boiling-up operation with the high heating capacity is called the high heating boiling-up operation. That is, the standard heating/boiling operation is an operation in which the heat pump unit 1 is operated at a first heating capacity H1 and the circulation pump 22 is operated at a first rotation speed N1, and the high heating/boiling operation is an operation in which the heat pump unit 1 is operated at a second heating capability H2 higher than the first heating capability H1 and the circulation pump 22 is operated at a second rotation speed N2 higher than the first rotation speed N1.

Surplus power acquisition unit 45 acquires the power generated by photovoltaic power generation device 200 and the power consumption of the facility in which hot water supply system 1000 is installed, and acquires the surplus power of photovoltaic power generation device 200 . The surplus power acquisition unit 45 calculates surplus power by, for example, subtracting the power consumption of the facility from the power generated by the photovoltaic power generation device 200 .

The functions of the stored hot water amount comparison unit 41, the target stored hot water amount setting unit 42, the boiling condition determination unit 43, the heating control unit 44, and the surplus power acquisition unit 45 are realized, for example, by the processor executing a control program stored in the memory.

Next, the operation of the hot water storage type water heater 100 of the present embodiment relating to the boiling operation will be described.

In the boiling operation, the heating control section 44 operates the heat pump unit 1 and the circulation pump 22 . Thereby, the water taken out from the lower part of the hot water storage tank 21 is sent to the heat pump unit 1 through the first going pipe 51 and the second going pipe 52 . The water heated by the heat pump unit 1 flows into the upper part of the hot water storage tank 21 through the first return pipe 53 and the second return pipe 54 .

In normal times, that is, when there is no surplus electric power, the heating control unit 44 starts boiling operation when the stored hot water amount comparison unit 41 determines that the current stored hot water amount Q1 is smaller than the target stored hot water amount Q2. In normal times, the heating control unit 44 carries out the standard heating boiling operation.

Further, in the present embodiment, when there is surplus power, the boiling-up operation is performed even if the current hot water storage amount Q1 is larger than the target hot water storage amount Q2. The operation of storage-type water heater 100 when there is surplus power will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of storage-type water heater 100 according to Embodiment 1. As shown in FIG. The control in FIG. 2 is started, for example, when the storage-type water heater 100 is powered on.

In step S1, the surplus power acquisition unit 45 acquires surplus power of the photovoltaic power generation device 200 and determines whether or not there is surplus power. When there is surplus power, the process proceeds to step S2, and when there is no surplus power, the process proceeds to "END". If it progresses to "END", it will return to "START" and the control shown in FIG. 2 will be repeated.

In step S2, the surplus power acquisition unit 45 determines whether or not the surplus power is greater than the preset power P1. The set electric power P1 is a value set to be equal to or higher than the electric power P0 required for the standard heating/boiling operation. If the surplus power is greater than the set power P1, the process proceeds to step S3, and if the surplus power is less than or equal to the set power P1, the process proceeds to step S4.

In step S3, the heating control unit 44 performs high heating boiling operation. That is, the heating control section 44 operates the heat pump unit 1 at the second heating capacity H2 and operates the circulation pump 22 at the second rotation speed N2. When the processing of step S3 is completed, the process returns to step S2, and when the surplus power is greater than the set power P1, the process proceeds to step S3 again. As a result, the high heating boiling operation is continued while the surplus power is greater than the set power P1. In step S2, when the surplus power is equal to or less than the set power P1, the process proceeds to step S4.

In step S4, the heating control unit 44 performs a standard heating boiling operation. That is, the heating control section 44 operates the heat pump unit 1 at the first heating capacity H1 and operates the circulation pump 22 at the first rotation speed N1. When the process of step S4 is completed, the process returns to step S1, and when there is surplus power and the surplus power is equal to or less than the set power P1, the process proceeds to step S4 again. As a result, there is surplus power, and the standard heating and boiling operation is continued while the surplus power is equal to or less than the set power P1.

Note that the heating control unit 44 ends the high heating boiling operation when the temperature of all the water in the hot water storage tank 21 detected by the thermistors 28a to 28c reaches or exceeds the sterilization possible temperature (for example, 65 ° C.) during the high heating boiling operation. That is, the heating control unit 44 performs the high heating boiling operation until the temperature of all the water in the hot water storage tank 21 detected by the thermistors 28a to 28c reaches or exceeds the sterilization possible temperature.

3 and 4, the effect obtained by the hot water storage type hot water heater 100 of the present embodiment will be described. FIG. 3 is a diagram showing values of surplus electric power with respect to time in hot water supply system 1000 according to Embodiment 1. In FIG. FIG. 4 is a diagram showing the value of the amount of heat given to the water in the hot water storage tank 21 with respect to time in (A) the hot water storage type hot water heater 100 according to Embodiment 1 or (B) the comparative example.

In FIG. 3, times T11 to T14 are daytime, and surplus power is generated during times T11 to T14. Between times T12 and T13, the surplus power exceeds the set power P1. That is, between times T12 and T13, the surplus electric power exceeds the electric power P0 required for the standard heating and boiling operation, so the surplus electric power cannot be effectively used in the standard heating and boiling operation.

FIG. 4B shows, as a comparative example, an example in which only standard heating and boiling operation is performed. In FIG. 4B, since surplus electric power is generated from time T11 to T14, the standard heating and boiling operation is performed using the surplus electric power. In the standard heating and boiling operation, the water in the hot water storage tank 21 is given a heat quantity Qa per unit time. Note that during times T11 to T12 and times T13 to T14 when the surplus electric power is less than the electric power P0 required for the standard heating and boiling operation, the amount of heat given to the water in the hot water storage tank 21 per unit time is less than the amount of heat Qa.

Also, in FIG. 4B, times T0 to T1 indicate nighttime. In the present embodiment, since the photovoltaic power generation device 200 is used as the power generation device, surplus power is not generated during the nighttime hours T0 to T1. Therefore, when the current hot water storage amount Q1 is less than the target hot water storage amount Q2 during times T0 to T1, the standard heating and boiling operation is performed using the electric power supplied from the external commercial power supply. As a result, the amount of heat Qa is given to the water in the hot water storage tank 21 per unit time from time T0 to time T1.

On the other hand, in the storage-type water heater 100 of the present embodiment, as shown in FIG. 4A, during the time T12 to T13 when the surplus power exceeds the set power P1, the surplus power is used to perform the high heating boiling operation. In the high heating boiling operation, the water in the hot water storage tank 21 is given a heat quantity Qb per unit time. The amount of heat Qb is greater than the amount of heat Qa. Therefore, the total amount of heat given to the water in the hot water storage tank 21 at times T12 to T13 is greater than in the comparative example in which only the standard heating and boiling operation is performed. As a result, surplus power can be effectively used. In addition, in the night time, in the comparative example, the heating operation is performed using the electric power of the commercial power supply from time T0 to T1, but in the hot water storage type water heater 100 of the present embodiment, by effectively using the surplus power generated in the daytime, the heating operation is performed at time T0 to T2, which is shorter than time T0 to T1. Therefore, it is possible to shorten the time of the boiling-up operation at night, and to save the power consumption of the commercial power source.

As described above, according to the hot water storage type water heater 100 of Embodiment 1, the hot water storage type water heater 100 is connected to a power generation device using renewable energy (solar power generation device 200 corresponds), and includes a heating device (heat pump unit 1) for heating water, a hot water storage tank 21 for storing the water heated by the heating device, a circulation pump 22 for sending water in the hot water storage tank 21 to the heating device, and the operation of the heating device and the circulation pump 22 is controlled. A control device 4 that performs a boiling-up operation for heating the water in the hot-water storage tank 21. The control device 4 can perform a standard heating-boiling operation in which the heating device is operated at a first heating capacity H1 and the circulation pump 22 is operated at a first rotation speed N1, and a high heating-boiling operation in which the heating device is operated at a second heating capability H2 higher than the first heating capability H1 and the circulation pump 22 is operated at a second rotation speed N2 higher than the first rotation speed N1, thereby generating power. When the surplus power of the device is greater than the preset power P1, the high heating boiling operation is performed. Since the high heating boiling operation is performed when the surplus power of the power generation device is greater than the set power P1, the power consumption per unit time can be increased, and the surplus power can be consumed in a shorter time. As a result, when surplus power is generated in the facility where the power generator is installed, the surplus power can be effectively used, and reverse power flow to the grid can be suppressed.

Further, in the high heating boiling operation, the rotation speed of the circulation pump 22 is higher than that in the standard heating boiling operation. Therefore, the high-temperature water on the upper layer side and the low-temperature water on the lower layer side, which are stored in a stacked state in the hot water storage tank 21, are agitated, and the temperature of the water on the lower layer side rises. As a result, the temperature of water entering the heat pump unit 1 rises, so that the difference between the target heating temperature in the heat pump unit 1 and the temperature of entering water becomes small, and the temperature of the water in the hot water storage tank 21 can be raised in a short time.

Further, according to the hot water storage type water heater 100 of Embodiment 1, when the surplus electric power becomes equal to or less than the set electric power P1 during the high heating boiling operation, the control device 4 changes from the high heating boiling operation to the standard heating boiling operation. Here, in the standard boiling-up heating operation, the rotational speed of the circulation pump 22 is lower and the flow rate of water entering the heat pump unit 1 is lower than in the high-heating boiling operation. Therefore, the COP (Coefficient Of Performance) is higher in the standard heating and boiling operation than in the high heating and boiling operation. Therefore, when the surplus power becomes equal to or less than the set power P1, the high heating/boiling operation can be switched to the standard heating/boiling operation with a high COP.

Further, according to the hot water storage type water heater 100 of Embodiment 1, the tank temperature detection unit (corresponding to the thermistors 28a to 28c) that detects the temperature of the water in the hot water storage tank 21 is provided. As a result, the entire inside of the hot water storage tank 21 can be sterilized while the surplus power is effectively used.

A modification of the first embodiment will be described.

In the first embodiment, the high heating boiling operation is performed when the surplus power is greater than the set power P1. However, the control device 4 may perform the high heating/boiling operation when the surplus electric power is greater than the set electric power P1 and the amount of heat that can be heated by the high heating/boiling operation due to the surplus electric power is larger than the difference between the current amount of hot water Q1 in the hot water storage tank 21 detected by the hot water amount detection unit (the stored hot water amount comparison unit 41 corresponds to this) and the target amount of stored hot water Q2. As a result, when the assumed amount of heat that can be boiled by the high heating boiling operation due to the surplus power is smaller than the difference between the current hot water storage amount Q1 and the target hot water storage amount Q2, the standard heating and boiling operation can be continued without switching to the high heating boiling operation.

Further, the control device 4 may perform the standard heating and boiling operation when the surplus electric power is greater than the set electric power P1 and the amount of heat that can be boiled by the standard heating and boiling operation due to the surplus electric power is larger than the difference between the current amount of hot water Q1 in the hot water storage tank 21 detected by the hot water amount detection unit and the target amount of stored hot water Q2. Thus, when the estimated amount of heat that can be boiled by the standard heating and boiling operation due to the surplus electric power is larger than the difference between the current hot water storage amount Q1 and the target hot water storage amount Q2, the standard heating and boiling operation can be continued without switching to the high heating and boiling operation.

Further, in the present embodiment, controller 4 is provided inside hot water storage unit 2 . However, the control device 4 may be installed outside the hot water storage unit 2 instead of inside the hot water storage unit 2 . Also, the functions of the control device 4 may be divided into a plurality of functions. For example, the functions of the control device 4 may be divided into the heating control unit 44 and functions other than the heating control unit 44, the heating control unit 44 may be provided in the heat pump unit 1, and the functions other than the heating control unit 44 may be provided in the hot water storage unit 2.

Further, in the present embodiment, an example has been described in which the three thermistors 28a to 28c are used as the tank internal temperature detection unit for detecting the temperature of hot water in the hot water storage tank 21, but the number of thermistors may be one, two, or four or more. A thermistor corresponding to at least the third thermistor 28c may be provided. That is, if a thermistor for detecting the temperature of the hot water in the lower part of the hot water storage tank 21 is provided, it is possible to detect the temperature of the hot water with the lowest temperature in the hot water storage tank 21, so when the temperature of the hot water in the lower part of the hot water storage tank 21 becomes equal to or higher than the sterilizable temperature, it can be determined that the temperature of all the water in the hot water storage tank 21 has reached the sterilizable temperature or higher.

1 heat pump unit 2 hot water storage unit 3 remote control device 4 control device 11 compressor 12 water refrigerant heat exchanger 13 expansion valve 14 air heat exchanger 15 refrigerant pipe 16 inlet 17 outlet 18 inlet pipe 19 outlet pipe 21 hot water storage tank 22 circulation pump 23 hot water mixing valve 23a hot water side inlet 23b water side inlet 23c outlet , 24 HP outlet, 25 HP return port, 26 water inlet, 27 hot water outlet, 28 a first thermistor, 28 b second thermistor, 28 c third thermistor, 41 hot water storage amount comparison unit, 42 target hot water storage amount setting unit, 43 boiling condition determination unit, 44 heating control unit, 45 surplus power acquisition unit, 51 first outgoing pipe, 52 second outgoing pipe, 53 first return Piping, 54 second return pipe, 55 first hot water supply pipe, 56 first water supply pipe, 57 second water supply pipe, 58 second hot water supply pipe, 100 hot water storage type water heater, 200 solar power generation device, 300 power conditioner, 1000 hot water supply system.

Claims (8)

A hot water storage type water heater connected to a power generation device using renewable energy,
a heating device for heating water;
a hot water storage tank for storing water heated by the heating device;
a circulation pump for sending water in the hot water storage tank to the heating device;
a control device for performing a boiling operation for controlling the operation of the heating device and the circulation pump to heat the water in the hot water storage tank;
with
The control device is
a standard heating and boiling operation in which the heating device is operated at a first heating capacity and the circulation pump is operated at a first rotation speed;
a high heating boiling operation in which the heating device is operated at a second heating capacity higher than the first heating capacity and the circulation pump is operated at a second rotation speed higher than the first rotation speed;
can be implemented and
When the surplus power of the power generation device is greater than the preset power, the high heating boiling operation is performed.
Storage hot water heater. A tank internal temperature detection unit that detects the temperature of water in the hot water storage tank,
The control device performs the high heating boiling operation until the temperature of all the water in the hot water storage tank detected by the tank internal temperature detection unit reaches or exceeds the sterilization possible temperature.
The hot water storage type water heater according to claim 1. The control device changes from the high heating boiling operation to the standard heating boiling operation when the surplus electric power becomes equal to or less than the set electric power during the high heating boiling operation.
The hot water storage type water heater according to claim 1 or 2. The control device determines the second heating capacity and the second rotation speed according to the amount of the surplus power.
The storage-type water heater according to any one of claims 1 to 3. A hot water storage amount detection unit that detects the amount of hot water stored in the hot water storage tank,
The control device determines the second heating capacity and the second rotation speed according to a difference between a current amount of hot water stored in the hot water tank and a target amount of hot water stored.
The hot water storage type water heater according to any one of claims 1 to 4. A hot water storage amount detection unit that detects the amount of hot water stored in the hot water storage tank,
The control device performs the high heating and boiling operation when the surplus electric power is greater than the set electric power and the amount of heat that can be boiled by the high heating and boiling operation due to the surplus electric power is greater than the difference between the current amount of hot water stored in the hot water storage tank and the target amount of hot water stored.
The hot water storage type water heater according to any one of claims 1 to 4. A hot water storage amount detection unit that detects the amount of hot water stored in the hot water storage tank,
The control device performs the standard heating and boiling operation when the surplus electric power is greater than the set electric power and the amount of heat that can be boiled by the standard heating and boiling operation due to the surplus electric power is greater than the difference between the current amount of hot water stored in the hot water storage tank and the target amount of hot water stored.
The hot water storage type water heater according to any one of claims 1 to 4. The power generation device is a solar power generation device,
The storage-type water heater according to any one of claims 1 to 7.

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