JP2023104720A - Storage water heater - Google Patents

Abstract

To provide a storage water heater advantageous to use surplus electric power obtained by photovoltaic power generation for hot water supply.SOLUTION: A storage water heater is configured to be capable of executing a boiling-up operation by using surplus electric power obtained from a photovoltaic power generator. As the boiling-up operation, the storage water heater can execute a normal boiling-up operation and an intermediate temperature boiling-up operation that is an operation in which a target boiling-up temperature is lower than that in the normal boiling-up operation. In the normal boiling-up operation, hot water caused to flow out from heating means is caused to flow into a hot water storage tank from an upper connection port, and in the intermediate temperature boiling-up operation, hot water caused to flow out from the heating means is caused to flow into the hot water storage tank from an intermediate part connection port. In the boiling-up operation, a control section executes the normal boiling-up operation by using commercial electric power in a night time zone, and executes the intermediate temperature boiling-up operation by using surplus electric power when surplus electric power amount is larger than reference amount in a daytime time zone.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a storage hot water heater.

Patent Literature 1 discloses a technique for appropriately controlling a heat pump hot water storage type hot water supply apparatus when surplus power is generated in a power generation apparatus using renewable energy. With this technology, when surplus power is generated by photovoltaic power generation, the heat pump is operated regardless of whether the current amount of hot water storage is the target amount of hot water storage, thereby suppressing reverse power flow to the grid.

JP 2011-4476 A

In the hot water storage type water heater, the amount of water to be pumped is determined during the night of the previous day according to the amount of hot water used each day, and is controlled to perform the determined amount of water. Therefore, in the technique of Patent Document 1, the surplus power is used to heat up more hot water than the amount used for the day, and there is a problem in terms of efficient use of the surplus power.

The present disclosure has been made to solve the problems described above, and an object thereof is to provide a hot water storage type water heater that is advantageous in utilizing surplus power generated by photovoltaic power generation for hot water supply.

A hot water storage type water heater of the present disclosure includes a hot water storage tank having a lower connection port, an upper connection port above the lower connection port, and an intermediate connection port between the upper connection port and the lower connection port; A heating means for heating the water taken out from the lower connection port of the tank, an information acquisition unit for acquiring information on the amount of surplus power, which is the amount of power generated by subtracting the amount of indoor power consumption from the PV power generation amount of the photovoltaic power generation device, a control unit for controlling a boiling operation in which the hot water flowing out of the heating means flows into the hot water storage tank based on the information acquired from the information acquisition unit, and the boiling operation includes normal boiling operation and target boiling operation. A medium-temperature boiling operation, which is an operation in which the raising temperature is lower than that of the normal boiling operation, can be executed. During the boiling operation, the hot water flowing out from the heating means is made to flow into the hot water storage tank from the intermediate connection port, and during the boiling operation, the control unit performs normal boiling operation using commercial power during the nighttime hours. However, when the surplus power amount is higher than the reference amount during the daytime, the medium temperature heating operation is performed using the surplus power.

According to the hot water storage type hot water heater of the present disclosure, it is advantageous in using surplus power generated by solar power generation for hot water supply.

It is a figure which shows the storage-type hot water heater 35 by embodiment. 3 is a diagram showing an example of a configuration of a controller 36 of the hot water storage type hot water heater 35 according to the embodiment; FIG. FIG. 3 is a configuration diagram of a circuit formed in normal boiling operation; FIG. 4 is a configuration diagram of a circuit formed in medium temperature boiling operation; 4 is a flow chart of a routine executed in the hot water storage type hot water heater of the embodiment.

Embodiments will be described below with reference to the drawings. Elements that are common or correspond to each figure are denoted by the same reference numerals, and overlapping descriptions are simplified or omitted.

Embodiment.
1. Circuit Configuration of Storage Hot Water Heater 35 FIG. 1 is a diagram showing a hot water storage hot water heater 35 according to an embodiment. As shown in FIG. 1 , the hot water storage type hot water heater 35 of the present embodiment includes a tank unit 33 , an HP (heat pump) unit 7 and a remote controller 44 . The HP unit 7 and the tank unit 33 are connected to each other via the HP outgoing pipe 14, the HP return pipe 15, and electrical wiring (not shown). A controller 36 is built in the tank unit 33 . The control unit 36 comprises, for example, a microcomputer having at least one memory and at least one processor. The operations of various valves, pumps, and the like provided in the tank unit 33 and HP unit 7 are controlled by a control section 36 electrically connected to them.

The remote control device 44 has a function of receiving a user's operation relating to a driving operation command, a change of set values, and the like. Remote control device 44 is an example of a user interface. The control unit 36 and the remote controller 44 are connected by wire or wirelessly so as to be capable of bidirectional data communication. Although not shown, the remote control device 44 includes a display unit for displaying information such as the state of the hot water heater 35, an operation unit such as switches operated by the user, a speaker, a microphone, and the like.

The external communication adapter 46 is connected to the remote control device 44 so as to allow bidirectional data communication. Wired communication or wireless communication may be used between the remote control device 44 and the external communication adapter 46 . The external communication adapter 46 and the HEMS controller 47 are connected wirelessly or by wire so as to be able to communicate with each other. The HEMS controller 47 is a controller of a home energy management system that manages electric power energy in the home. The HEMS controller 47 can communicate wirelessly or by wire with household electrical appliances used at home. The home appliance may include at least one of, for example, an air conditioner, a washing machine, a lighting fixture, a bathroom dryer, a bathroom ventilation fan, a kitchen ventilation fan, an IH (Induction Heating) cooker, a microwave oven, a dishwasher, and a television. . HEMS controller 47 can control home appliances automatically or in response to user instructions received from remote control device 44 . The HEMS controller 47 and home appliances may be able to communicate via a home network. Also, the HEMS controller 47 may be configured to exchange information with an external server via the Internet communication network. An example of an external server is a Meteorological Agency server that distributes weather forecast information.

A home having a hot water storage type hot water heater 35 is equipped with a photovoltaic power generation device 48 . The photovoltaic power generation device 48 has a photovoltaic panel and an inverter that converts the DC power generated by the photovoltaic panel into AC power. Electric power generated by the photovoltaic power generation device 48 can be supplied to the hot water storage type water heater 35 and household appliances (not shown) via the distribution board. The HEMS controller 47 is communicably connected to the photovoltaic power generation device 48 and can collect power generation information of the photovoltaic power generation device 48 . In addition, the HEMS controller 47 is connected to a distribution board (not shown), and can acquire information on the state of power usage in the home and information on the amount of power consumption for each branch circuit of the distribution board.

Electric power is supplied to the home from the commercial power supply of the electric power company during the time period when the photovoltaic power generation device 48 does not generate power. Moreover, when the power generated by the solar power generation device 48 is insufficient for the household power consumption during power generation by the solar power generation device 48, the shortage of power is supplied to the home from the commercial power source. Hereinafter, power supplied from a commercial power supply to homes is referred to as "commercial power".

If the power generated by the photovoltaic power generation device 48 is greater than the total power consumption of household appliances other than the hot water storage type water heater 35 during power generation by the photovoltaic power generation device 48, the surplus power is used to The water heater 35 can perform the boiling operation. Below, the boiling-up operation using surplus electric power is called "surplus electric-heating operation."

The amount of power generated per hour by the photovoltaic power generation device 48 is hereinafter referred to as "PV power generation amount". Further, the power consumption per hour of the hot water storage type hot water heater 35 is hereinafter referred to as "hot water heater power consumption". In addition, the power consumption per hour of home appliances other than the hot water storage type hot water heater 35 is referred to as "home power consumption". A value obtained by subtracting the in-house power consumption from the PV power generation amount is referred to as "surplus power amount". When the surplus power amount is greater than 0, the surplus power boiling operation can be performed. In particular, when the amount of surplus power is greater than the amount of power consumed by the water heater, the surplus power boiling operation can be executed without purchasing commercial power.

The HP unit 7 is an example of heating means for heating water. The HP unit 7 includes a refrigerant circuit in which a compressor 1 , a water-refrigerant heat exchanger 3 , an expansion valve 4 , and an air heat exchanger 6 are annularly connected by a refrigerant circulation pipe 5 . The HP unit 7 operates a heat pump cycle using this refrigerant circuit. In the water-refrigerant heat exchanger 3, heat is exchanged between the refrigerant compressed by the compressor 1 and the water guided from the tank unit 33, thereby heating the water.

The HP unit 7 includes a hot water outlet temperature sensor 39 provided on a hot water outlet of the water-refrigerant heat exchanger 3 or a pipe communicating with the hot water outlet, and a water inlet of the water-refrigerant heat exchanger 3 or a pipe communicating with the water inlet. and an incoming water temperature sensor 40 provided. The outlet hot water temperature sensor 39 detects the temperature of hot water flowing out from the water-refrigerant heat exchanger 3 . The incoming water temperature sensor 40 detects the temperature of water flowing into the water-refrigerant heat exchanger 3 .

The tank unit 33 incorporates the following various parts, piping, and the like. The hot water storage tank 8 stores hot water. Inside the hot water storage tank 8, temperature stratification can be formed in which the upper side has a higher temperature and the lower side has a lower temperature due to the difference in water density due to temperature.

As shown in FIG. 1, the hot water storage tank 8 has an upper portion, an intermediate portion, and a lower portion. The intermediate portion of the hot water storage tank 8 is a portion of height between the upper portion of the hot water storage tank 8 and the lower portion of the hot water storage tank 8 . Note that the hot water storage tank 8 is not limited to a single tank as shown in the drawing, and may include a plurality of tanks connected in series. In the present disclosure, regarding the position of the hot water storage tank 8 in the height direction, that is, in the vertical direction, if the hot water storage tank 8 is provided with a plurality of tanks connected in series, the top tank to the bottom The vertical position shall be specified in the entire hierarchy up to the tank.

At the bottom of the hot water storage tank 8, a water inlet 8a, a water outlet 8b as a lower connection port, and a hot water inlet 8c are provided. At the top of the hot water storage tank 8, a hot water introduction outlet 8d is provided as an upper connection port. An intermediate portion of the hot water storage tank 8 is provided with a medium temperature water introduction port 8e as an intermediate portion connection port.

A third water supply pipe 9c is connected to the water inlet 8a. Water supplied from a water source such as tap through the first water supply pipe 9a is pressure-regulated by the pressure reducing valve 31 and flows into the hot water storage tank 8 through the third water supply pipe 9c. On the surface of the hot water storage tank 8, an upper stored hot water temperature sensor 41, an intermediate stored hot water temperature sensor 42, and a lower stored hot water temperature sensor 43 are attached at different height positions. The upper hot water storage temperature sensor 41 detects the upper water temperature, which is the temperature of the water in the upper part of the hot water storage tank 8 . An intermediate hot water temperature sensor 42 detects an intermediate water temperature, which is the water temperature in the intermediate part of the hot water storage tank 8 . In the illustrated example, the intermediate hot water storage temperature sensor 42 detects the water temperature at a position at the same height as the intermediate hot water inlet 8e or at a height close to the intermediate hot water inlet 8e. A lower stored hot water temperature sensor 43 detects the lower water temperature, which is the temperature of the water in the lower part of the hot water storage tank 8 . The control unit 36 detects the temperature distribution of the hot water in the hot water storage tank 8 with the upper hot water storage temperature sensor 41, the middle hot water storage temperature sensor 42, and the lower hot water storage temperature sensor 43, thereby detecting the remaining hot water amount and the heat storage amount in the hot water storage tank 8. can also be detected. Note that four or more stored hot water temperature sensors may be provided in the hot water storage tank 8 without being limited to the illustrated example.

The tank unit 33 incorporates the bath heat exchanger 20 and the bath circulation pump 29 . The bath heat exchanger 20 has a primary side flow path and a secondary side flow path. The bath heat exchanger 20 corresponds to a heat exchanger that exchanges heat between hot water flowing through the primary channel and bath water flowing through the secondary channel. In this embodiment, an example in which bath water circulating from the bathtub 30 of a bath flows through the secondary flow path will be described.

The bath-going pipe 27 connects between the outlet of the secondary-side channel of the bath heat exchanger 20 and the bathtub 30 . A bath-going temperature sensor 37 for detecting the temperature of bath water flowing out from the bath heat exchanger 20 is installed in the middle of the bath-going pipe 27 . The bath return pipe 28 connects between the entrance of the secondary side channel of the bath heat exchanger 20 and the bathtub 30 . In the middle of the bath return pipe 28, there are provided a bath circulation pump 29 for circulating the bath water to the secondary flow path of the bath heat exchanger 20, and a bath water pump for detecting the temperature of the bath water discharged from the bathtub 30. A return temperature sensor 38 is provided.

The tank unit 33 further incorporates a three-way valve 11, a heat source pump 12, a four-way valve 18, and a four-way valve 19 for medium temperature. The three-way valve 11, the four-way valve 18, and the medium temperature four-way valve 19 each correspond to a channel switching means capable of switching the channel of hot water. The hot water storage type hot water heater 35 is provided with a piping device including these flow path switching means, the HP outgoing piping 14 and the HP returning piping 15, and piping to be described later. The heat source pump 12 is a pump for circulating hot water in this piping device, and is arranged in the HP outgoing piping 14 .

The three-way valve 11 has ports a and b serving as inlets and a port c serving as an outlet. The three-way valve 11 is configured to be switchable between two paths of ac and bc. The four-way valve 18 has ports b and c serving as inlets and ports a and d serving as outlets. The four-way valve 18 is configured to be switchable between four paths ba, bd, ca, and cd. The medium-temperature four-way valve 19 has an a port as an inlet and b, c, and d ports as outlets. The medium-temperature four-way valve 19 is configured to be switchable between three paths ad, ab, and ac.

The tank unit 33 includes a water outlet pipe 10, a lower hot water supply pipe 13a, an upper hot water supply pipe 13b, an HP outgoing pipe 14, a first bypass pipe 16, a second bypass pipe 17, a medium temperature pipe 19a, a hot water introduction pipe 20a, and It has a hot water lead-out pipe 20b. The water outlet pipe 10 connects between the water outlet 8 b and the a port of the three-way valve 11 . The HP outgoing pipe 14 connects between the c port of the three-way valve 11 and the water inlet of the water-refrigerant heat exchanger 3 in the HP unit 7 . The HP return pipe 15 connects between the hot water outlet of the water-refrigerant heat exchanger 3 and the c port of the four-way valve 18 . The lower hot water supply pipe 13a connects between the d port of the four-way valve 18 and the a port of the intermediate temperature four-way valve 19 . The first bypass pipe 16 connects between the a port of the four-way valve 18 and the hot water inlet 8c. The warm water introduction pipe 20a connects between the c port of the intermediate temperature four-way valve 19 and the inlet of the primary side flow path of the heat exchanger 20 for bath. The upper hot water supply pipe 13b connects between the d port of the intermediate temperature four-way valve 19 and the hot water introduction outlet 8d. The intermediate temperature pipe 19a connects between the b port of the intermediate temperature four-way valve 19 and the intermediate temperature water inlet 8e.

The hot water lead-out pipe 20 b connects between the outlet of the primary side flow path of the bath heat exchanger 20 and the b port of the three-way valve 11 . The second bypass pipe 17 branches from between the heat source pump 12 and the HP unit 7 in the HP outgoing pipe 14 and is connected to the b port of the four-way valve 18 .

The tank unit 33 has a first water supply pipe 9a, a second water supply pipe 9b, a third water supply pipe 9c, a hot water supply mixing valve 22, a bath mixing valve 23, a first hot water supply pipe 24, and a second hot water supply pipe 25. ing.

The hot water supply mixing valve 22 is mixing means having a first inlet, a second inlet, and an outlet. The bath mixing valve 23 is mixing means with a first inlet, a second inlet and an outlet.

One end of the first water supply pipe 9a is connected to a water source such as tap water. A second water supply pipe 9b and a third water supply pipe 9c are connected to the other end of the first water supply pipe 9a through a pressure reducing valve 31 . The second water supply pipe 9b is connected to the first inlets of each of the hot water supply mixing valve 22 and the bath mixing valve 23 . One end of the hot water supply pipe 21 communicates with the hot water introduction outlet 8d. The other end of the hot water supply pipe 21 is connected to the second inlets of each of the hot water supply mixing valve 22 and the bath mixing valve 23 .

The mixing valve 22 for hot water supply adjusts the flow rate ratio between the high temperature water supplied from the hot water storage tank 8 through the hot water supply pipe 21 and the low temperature water supplied from the second water supply pipe 9b so that the user can operate the remote control device. Hot water having a set temperature set in 44 is generated and flowed into the first hot water supply pipe 24 . The hot water whose temperature is adjusted by the hot water supply mixing valve 22 is supplied from the first hot water supply pipe 24 via the hot water supply valve 34 to, for example, a faucet (not shown) such as a shower or a faucet.

The bath mixing valve 23 is operated by the user by adjusting the flow rate ratio between the high temperature water supplied from the hot water storage tank 8 through the hot water supply pipe 21 and the low temperature water supplied from the second water supply pipe 9b. Hot water having a set temperature set in 44 is generated and flowed into the second hot water supply pipe 25 . The hot water adjusted to the set temperature by the bath mixing valve 23 flows into the bathtub 30 through the bath flow sensor 45, the bath solenoid valve 26, the bath pipe 27, and the bath return pipe 28.

2. Configuration of Control Unit 36 FIG. 2 is a diagram showing an example of the configuration of the control unit 36 of the storage-type water heater 35 according to the embodiment. The controller 36 controls each part provided in the hot water storage type hot water heater 35 . In the example shown in FIG. 2, the control unit 36 has an information acquisition unit 36a, an arithmetic processing unit 36b, a device control unit 36c, a communication unit 36d, and a storage unit 36e. The control unit 36 may implement various functions by executing software on an arithmetic device such as a microcomputer. Alternatively, the control unit 36 may be configured by hardware such as a circuit device that implements various functions.

The information acquisition unit 36 a acquires detection information from various sensors and equipment operation information such as the number of revolutions of the heat source pump 12 . Further, the information acquisition unit 36 a acquires information on the current surplus power amount from the HEMS controller 47 connected to the hot water storage type water heater 35 .

There is an electricity rate system in which the unit price of electricity when purchasing commercial power becomes cheaper in the middle of the night. Hereinafter, the late-night hours when the power rate unit price is relatively low may be referred to as "nighttime", and the hours other than "nighttime" may be referred to as "daytime". The specific time zones of "nighttime" and "daytime" differ depending on the electricity rate system and the like. As an example, the time period from 23:00 to 7:00 may be defined as "night" and the time period from 7:00 to 23:00 may be defined as "daytime."

After the load for the day ends, the arithmetic processing unit 36b determines the target boiling amount at night corresponding to the hot water supply load and the hot water supply load using the predicted values of the hot water supply load and the hot water supply load for the next day. good too. The device control unit 36c controls the compressor 1, the expansion valve 4, the three-way valve 11, the four-way valve 18, the medium-temperature four-way valve 19, the bath mixing valve 23, the bath solenoid valve, and the like according to the processing result of the arithmetic processing unit 36b. 26, hot water mixing valve 22, heat source pump 12 and bath circulation pump 29 are controlled.

The communication unit 36d is connected to the remote control device 44 for wired communication or wireless communication, and transmits and receives information to and from the remote control device 44 . The communication unit 36d also communicates with the HEMS controller 47 and receives information on the amount of surplus power. The storage unit 36e stores various values used in each unit of the control unit 36. FIG. For example, the storage unit 36e stores a target boiling amount for nighttime, a target boiling amount for daytime, and the amount of hot water currently stored in the hot water storage tank 8 for heat storage management.

3. Boiling Operation In the present embodiment, the control unit 36 can alternatively execute a normal boiling operation or a medium temperature boiling operation as the boiling operation. The medium-temperature boiling operation is an operation in which the target boiling temperature is lower than that of the normal boiling operation. The target boiling temperature for the medium temperature boiling operation may be, for example, 40°C. The target boiling temperature for the normal boiling operation is preferably 80°C or higher. The target boiling temperature for the normal boiling operation may be, for example, 80°C. The hot water produced by the normal boiling operation is hereinafter referred to as "high temperature water". The hot water generated by the intermediate temperature boiling operation is hereinafter referred to as "intermediate hot water". Further, the water from the water source introduced into the hot water storage tank 8 from the water inlet 8a is hereinafter referred to as "low temperature water".

The circuit from the lower part of the hot water storage tank 8 to the hot water storage tank 8 through the HP unit 7 differs between the normal boiling operation and the medium temperature boiling operation. FIG. 3 is a configuration diagram of a circuit formed in normal boiling operation. In the normal boiling operation, a circuit is formed from the lower part of the hot water storage tank 8 to the upper part of the hot water storage tank 8 through the HP unit 7, and hot water heated by the HP unit 7, that is, high-temperature water is accumulated in the hot water storage tank 8. be. The control unit 36 controls the start and stop of the normal boiling operation according to the amount of hot water remaining in the hot water storage tank 8 or the amount of heat stored. In normal boiling operation, the HP unit 7 and the heat source pump 12 are operated as follows. Low-temperature water in the lower part of the hot water storage tank 8 flows into the water-refrigerant heat exchanger 3 via the water outlet 8b, the water outlet pipe 10, the three-way valve 11, the HP outgoing pipe 14, and the heat source pump 12. The high-temperature water generated by heating this low-temperature water in the water-refrigerant heat exchanger 3 is supplied to the HP return pipe 15, the four-way valve 18, the lower hot-water supply pipe 13a, the medium-temperature four-way valve 19, and the upper hot-water supply pipe 13b. and flows into the hot water storage tank 8 from the hot water introduction outlet 8d. Such a circuit in which hot water circulates normally corresponds to a boiling circuit. When the normal boiling operation is performed, high-temperature water is stored in the hot water storage tank 8 from the top to the bottom, and the layer of this high-temperature water gradually thickens. When the amount of hot water stored in the hot water storage tank 8 or the amount of heat stored in the hot water storage tank 8 detected by the upper hot water storage temperature sensor 41, the middle hot water storage temperature sensor 42, and the lower hot water storage temperature sensor 43 exceeds a specified amount, the control unit 36 ends the normal boiling operation. do.

FIG. 4 is a configuration diagram of a circuit formed in medium temperature boiling operation. In the medium temperature boiling operation, a circuit is formed from the lower part of the hot water storage tank 8 through the HP unit 7 to the middle part of the hot water storage tank 8, and the hot water heated by the HP unit 7, that is, medium temperature hot water is accumulated in the hot water storage tank 8. is. In the middle temperature boiling operation, the HP unit 7 and the heat source pump 12 are operated as follows. Low-temperature water in the lower part of the hot water storage tank 8 flows into the water-refrigerant heat exchanger 3 via the water outlet 8b, the water outlet pipe 10, the three-way valve 11, the HP outgoing pipe 14, and the heat source pump 12. Medium temperature water generated by heating this low temperature water in the water-refrigerant heat exchanger 3 passes through the HP return pipe 15, the four-way valve 18, the lower hot water supply pipe 13a, the medium temperature four-way valve 19, and the medium temperature pipe 19a. Then, the hot water flows into the hot water storage tank 8 from the medium temperature water inlet 8e. A circuit in which hot water circulates in this manner corresponds to a medium-temperature boiling circuit. When the medium temperature boiling operation is performed, medium hot water is stored in the hot water storage tank 8 from the middle portion toward the lower portion, and the layer of medium hot water gradually becomes thicker. When the water temperature in the lower part of the hot water storage tank 8 detected by the lower hot water storage temperature sensor 43 reaches or exceeds the target boiling temperature, the control unit 36 ends the medium temperature boiling operation.

The control unit 36 performs normal boiling operation using commercial power mainly during nighttime hours. In addition, when the surplus electric power boiling operation can be executed during the daytime, the control unit 36 executes the medium temperature boiling operation using the surplus electric power. The following effects are obtained by performing medium-temperature boiling operation using surplus electric power. Since the low-temperature water in the hot water storage tank 8 is replaced with medium-temperature water, the boiling time is shortened in the subsequent normal boiling operation during the nighttime hours. This is advantageous in suppressing power consumption. Also, in the event of a disaster such as a water outage or power outage, it is conceivable to use the hot water in the hot water storage tank 8 as it is. In such a case, the intermediate hot water stored in the hot water storage tank 8 is convenient to use.

Further, even when the surplus electric power boiling operation can be executed during the daytime, the control unit 36 determines that the intermediate water temperature detected by the intermediate hot water storage temperature sensor 42 is the target boiling temperature in the middle temperature boiling operation. If it is higher than , the medium-temperature boiling operation using the surplus power is not performed. As a result, it is possible to prevent the temperature of the intermediate hot water in the hot water storage tank 8 from dropping due to the intermediate temperature boiling operation using the surplus electric power.

Further, if the amount of surplus electric power becomes equal to or less than the reference amount during execution of the medium-temperature boiling operation using surplus electric power, the control unit 36 ends the medium-temperature boiling operation that is being executed. As a result, it is possible to reliably prevent the purchase of commercial power, which is advantageous in reducing electricity charges.

In addition, when the lower water temperature detected by the lower stored hot water temperature sensor 43 becomes equal to or higher than the target boiling temperature in the middle temperature boiling operation during execution of the middle temperature boiling operation using the surplus electric power, the control unit 36 End the medium-temperature boiling operation using As a result, it is possible to prevent the medium-temperature boiling operation using the surplus power from being continued more than necessary, thereby preventing unnecessary consumption of the surplus power.

4. Specific Processing of Middle-Temperature Boiling Operation Using Surplus Electricity FIG. 5 is a flow chart of a routine executed in the storage-type water heater of the embodiment. The control unit 36 executes medium-temperature boiling operation using the surplus electric power, for example, according to the flowchart shown in FIG.

In step S100, it is determined whether the amount of surplus power is greater than the reference amount. Here, the information acquisition unit 36 a of the control unit 36 acquires information on the current surplus power amount from the HEMS controller 47 . A preset value greater than 0, for example, is read as the reference amount. The larger the reference amount is, the more the amount of commercial electric power used in the medium-temperature boiling operation can be reduced. In particular, by setting the reference amount to a value equal to or greater than the electric power consumption of the water heater, medium-temperature boiling operation using only surplus electric power becomes possible. In step S100, if the determination is accepted, the process proceeds to step S102, and if the determination is not accepted, the process of this routine ends.

In step S102, a target boiling temperature is set. Here, the target boiling temperature is set to 40° C., for example, as a boiling temperature suitable for medium temperature boiling operation. Alternatively, the target boiling temperature may be set according to the surplus power amount. That is, there is a tendency that the higher the target boiling temperature, the larger the electric power consumption of the water heater. Therefore, when the amount of surplus power is large, the target boiling temperature may be set higher than when the amount of surplus power is small. After the process of step S102 is completed, the process proceeds to step S104.

In step S104, it is determined whether or not the intermediate water temperature detected by the intermediate hot water storage temperature sensor 42 is higher than the target boiling temperature. As a result, when the establishment of the determination is recognized, the process of this routine is terminated, and when the establishment of the determination is not recognized, the process proceeds to step S106.

In step S106, a medium temperature boiling circuit is formed by switching the three-way valve 11, the four-way valve 18, and the four-way valve 19 for medium temperature. After the process of step S106 is completed, the process proceeds to step S108. In step S108, the medium temperature boiling operation is performed by driving the heat source pump 12 and the HP unit 7 using the surplus electric power. Note that the rotation speed of the heat source pump 12 in the middle temperature boiling operation is set to a higher value than in the normal boiling operation. For example, if the rotation speed of the heat source pump 12 in normal boiling operation is 2000 rpm, the rotation speed of the heat source pump 12 in medium temperature boiling operation is set to 4000 rpm. Further, the rotational speed of the heat source pump 12 may be set to be higher as the target boiling temperature is lower. When the process of step S108 is executed, medium temperature water accumulates in the middle portion of the hot water storage tank 8, and the temperature boundary layer between the lower low temperature water approaches the lower portion of the hot water storage tank 8. After the process of step S108 is executed, the process proceeds to step S110.

In step S110, it is determined whether or not the lower water temperature detected by the lower stored hot water temperature sensor 43 is equal to or higher than the target boiling temperature. As a result, if the determination is not established, it is determined that low-temperature water still remains in the lower portion of the hot water storage tank 8, and the process proceeds to step S112. On the other hand, if the determination is accepted, it is determined that all the low-temperature water in the lower part of the hot water storage tank 8 has been replaced with medium-temperature water, and the process proceeds to step S114.

In step S112, it is determined whether or not the current amount of surplus power is equal to or less than the reference amount. Here, the information acquisition unit 36 a of the control unit 36 acquires information on the current surplus power amount from the HEMS controller 47 . If the determination is not established in step S112, it is determined that the medium-temperature boiling operation using the surplus power can be executed, and the process proceeds to step S110 again. On the other hand, if the determination is accepted, it is determined that the medium-temperature boiling operation using the surplus power cannot be executed, and the process proceeds to step S114. In step S114, the heat source pump 12 and the HP unit 7 are stopped and the medium temperature boiling operation is terminated.

5. Modifications Storage-type hot water heater 35 of the embodiment may adopt the following modifications.

Surplus power may remain after the middle temperature boiling operation using the surplus power in the daytime is executed and all of the low temperature water in the hot water storage tank 8 is replaced with medium temperature water. In such a case, the normal boiling operation using the surplus power may be performed even during the daytime hours. In this case, after the establishment of the determination in step S110 is recognized in the routine shown in FIG. A normal boiling operation using electric power may be executed. A value preset as a value greater than 0 can be used as the second reference amount. Further, by setting the second reference amount to a value equal to or greater than the amount of electric power consumed by the water heater in normal boiling operation, normal boiling operation using only surplus electric power becomes possible. According to such control, the amount of high-temperature water stored in the upper part of the hot water storage tank 8 can be increased by the normal boiling operation after the medium-temperature boiling operation. The amount of heat exchanged in the heat exchanger 20 can be sufficiently increased, and an appropriate reheating operation can be performed.

When the HEMS controller 47 is configured to be able to receive the weather forecast information distributed by the Meteorological Agency server from the Internet communication network, it normally uses commercial power during the nighttime hours of the day according to the received weather forecast information. A boiling adjustment process may be executed to adjust the amount of low-temperature water remaining in the hot water storage tank 8 when the boiling operation is executed. In the boiling adjustment process, for example, the boiling temperature in normal boiling operation at nighttime on the current day may be changed based on the next day's weather included in the weather forecast information. In this case, the communication unit 36d receives, from the HEMS controller 47, information related to prediction of the surplus power amount for the next day, such as weather forecast information for the next day. For example, the weather forecast information for the next day is fine weather, and the amount of PV power generated by the photovoltaic power generation device 48 is expected to increase. If so, the target boiling temperature is set to the maximum temperature higher than the normal temperature in the normal boiling operation at night on the day. For example, the normal temperature is 80°C and the maximum temperature is 90°C. The third reference amount here is a value set in advance as an amount of electric power capable of executing medium-temperature boiling operation using surplus electric power. As a result, the position of the temperature boundary layer between the low-temperature water and the high-temperature water inside the hot water storage tank 8 is moved higher than when the target boiling temperature is low, while securing the amount of hot water or heat stored in the hot water storage tank 8. be able to. As a result, when medium-temperature water is introduced into the hot water storage tank 8 from the medium-temperature water introduction port 8e in medium-temperature boiling operation using surplus power during the daytime of the next day, it is possible to introduce the medium-temperature water to the high-temperature water side of the temperature boundary layer. can be suppressed.

On the other hand, for example, if the weather forecast information for the next day is cloudy or rainy, and the amount of PV power generated by the photovoltaic power generation device 48 is expected to decrease, the predicted amount of surplus power is expected to decrease below the third reference amount. It is expected that the number of opportunities for implementing the medium temperature boiling operation used will decrease. Therefore, in such a case, the target boiling temperature is set to the normal temperature in the normal boiling operation at night on the day. As a result, the COP improvement effect of increasing the COP of the HP unit 7 due to the low boiling temperature can be expected.

In the boiling adjustment process, when the target boiling temperature is set to a maximum temperature higher than the normal temperature and the target boiling amount for the night of the day is about the entire amount of the hot water storage tank 8, the target boiling amount is set. It is also possible to dare not boil the whole amount of the hot water storage tank 8 by reducing it. As a result, it is possible to suppress the power consumption of the normal heating operation at night, and to secure low-temperature water in the lower part of the hot water storage tank 8 in preparation for the medium-temperature boiling operation of the next day.

REFERENCE SIGNS LIST 1 compressor 3 water refrigerant heat exchanger 4 expansion valve 5 refrigerant circulation pipe 6 air heat exchanger 7 HP unit 8 hot water storage tank 8a water inlet 8b water outlet 8c hot water inlet 8d Hot water inlet 8e Intermediate water inlet 9a First water supply pipe 9b Second water supply pipe 9c Third water supply pipe 10 Water outlet pipe 11 Three-way valve 12 Heat source pump 13a Lower hot water supply pipe 13b Upper part Hot water supply pipe 14 HP forward pipe 15 HP return pipe 16 First bypass pipe 17 Second bypass pipe 18 Four-way valve 19 Medium temperature four-way valve 19a Medium temperature pipe 20 Bath heat exchanger 20a Hot water introduction Piping 20b Hot water lead-out pipe 21 Hot water supply pipe 22 Mixing valve for hot water supply 23 Mixing valve for bath 24 First hot water supply pipe 25 Second hot water supply pipe 26 Electromagnetic valve for bath 27 Pipe to/from bath 28 Return pipe to bath 29 bath circulation pump, 30 bathtub, 31 pressure reducing valve, 33 tank unit, 34 hot water tap, 35 storage hot water heater, 36 control unit, 36a information acquisition unit, 36b arithmetic processing unit, 36c device control unit, 36d communication unit, 36e storage unit 37 bath temperature sensor 38 bath return temperature sensor 39 outlet hot water temperature sensor 40 inlet water temperature sensor 41 upper hot water storage temperature sensor 42 middle hot water storage temperature sensor 43 lower hot water storage temperature sensor 44 remote controller 45 bath flow sensor, 46 external communication adapter, 47 HEMS controller, 48 photovoltaic power generation device

Claims (8)

a hot water storage tank having a lower connection port, an upper connection port above the lower connection port, and an intermediate connection port between the upper connection port and the lower connection port;
heating means for heating water taken out from the lower connection port of the hot water storage tank;
an information acquisition unit that acquires information on a surplus power amount, which is the power amount obtained by subtracting the home power consumption from the PV power generation amount of the photovoltaic power generation device;
a control unit for controlling a boiling operation in which the hot water flowing out from the heating means flows into the hot water storage tank based on the information acquired from the information acquisition unit;
with
As the boiling operation, a normal boiling operation and a medium temperature boiling operation in which a target boiling temperature is lower than that of the normal boiling operation can be performed,
During the normal boiling operation, the hot water flowing out from the heating means is allowed to flow into the hot water storage tank from the upper connection port,
During the medium temperature boiling operation, the hot water flowing out from the heating means is allowed to flow into the hot water storage tank from the intermediate connection port,
In the heating operation, the control unit executes the normal heating operation using commercial power during the night time period, and uses the surplus power when the surplus electric power amount is higher than the reference amount during the daytime time period. A hot water storage type hot water heater configured to perform the medium temperature boiling operation as described above. An intermediate hot water temperature sensor for detecting an intermediate water temperature, which is the temperature of hot water at the intermediate connection port of the hot water storage tank,
2. The hot water storage type water heater according to claim 1, wherein said controller is configured not to execute said middle temperature boiling operation when said middle portion water temperature is higher than said target boiling temperature in said middle temperature boiling operation. The control unit is configured to end the medium-temperature boiling operation when the surplus power amount becomes equal to or less than the reference amount during execution of the medium-temperature boiling operation using the surplus power. The hot water storage type water heater according to claim 1 or claim 2. a lower stored hot water temperature sensor for detecting a lower water temperature, which is the temperature of hot water at the lower connection port of the hot water storage tank,
The control unit terminates the medium-temperature boiling operation when the lower water temperature reaches or exceeds the target boiling temperature in the medium-temperature boiling operation during execution of the medium-temperature boiling operation using the surplus electric power. The hot water storage type hot water heater according to any one of claims 1 to 3, wherein the hot water heater is configured as follows. When the lower water temperature is equal to or higher than the target boiling temperature in the middle temperature boiling operation, the control unit uses the surplus power to The hot water storage type water heater according to claim 4, further configured to perform a boiling operation. The control unit is capable of receiving weather forecast information, and according to the received weather forecast information, when performing the normal boiling operation using commercial power during the night time of the day, 6. The hot water storage type water heater according to any one of claims 1 to 5, wherein a boiling adjustment process is performed to adjust the amount of low-temperature water remaining in the hot water storage type hot water supply machine. In the heating adjustment process, the control unit calculates a predicted surplus power amount that is a predicted value of the surplus power amount for the next day from the weather forecast information, and if the predicted surplus power amount is greater than a third reference amount, The hot water storage type water heater according to claim 6, wherein the target boiling temperature of the normal boiling operation is set higher than when the predicted surplus power amount is small. In the heating adjustment process, when the predicted surplus power amount is greater than the third reference amount, the control unit performs the normal heating operation using commercial power during the night time period of the current day. 8. The hot water storage type water heater according to claim 7, wherein the target boiling amount is reduced when the target boiling amount of is the full amount of the hot water storage tank.

Images