JP5891944B2 - Electric water heater - Google Patents

Description

  The present invention relates to an electric water heater having a function of generating hot water using a commercial power source and solar power generation.

  As a prior art, for example, as described in Patent Document 1, a hot water storage type hot water heater that generates hot water using electric power obtained by solar power generation and commercial electric power (midnight electric power) is known. In the prior art, when the weather forecast information acquired by the weather information acquisition means matches the preset weather information, hot water is stored using daytime power generated by solar power generation instead of midnight power. It is configured.

JP 2008-2702 A

  However, the conventional technology only determines whether or not hot water can be stored by solar power generation based on weather forecast information, and does not consider the cost of electric power. However, there is a problem that hot water is stored using expensive electric power.

  The present invention has been made to solve the above-described problems, and automatically selects and uses electric power used for hot water storage operation among electric power by private power generation and late-night electric power while considering cost merit of the user. An object of the present invention is to provide an electric water heater capable of promoting cost reduction of electric power.

The electric hot water supply apparatus according to the present invention is operated by commercial electric power and solar power generation power, and is capable of performing a hot water storage operation that heats low temperature water and stores high temperature water in a hot water storage tank, and an electric power charge is low When the hot water storage operation is executed on the next day by solar power generation , and the first hot water charge calculation means for calculating the electricity charge when the hot water storage operation is performed using commercial power during the late-night power hours , A second hot water storage fee calculating means for calculating the electric power charge when the electricity is sold as the self-generated hot water storage hot water charge, a weather forecast acquisition means for acquiring the next day's weather forecast, and hot water storage by solar power generation Electricity sales profit calculation means that calculates the maximum electricity sales profit , which is the next day's electricity sales charge obtained without running , based on weather forecasts at least, and commercial power obtained by subtracting the midnight hot water storage charge from the maximum electricity sales profit Electric power And profits during hot water, based on the magnitude relationship between the self-generation hot-water storage time benefits obtained by subtracting the self-generating hot water storage rates from the maximum power selling profit, power used for the actual hot-water stocking operation of the commercial power and solar power generation Power selection means for selecting.

  According to the present invention, even if the user does not perform an extra selection operation or the like, a hot water storage operation is efficiently performed by automatically selecting a power that is advantageous in terms of cost from among privately generated power and midnight power. Can be improved. Thereby, even if it is disadvantageous in terms of cost, it is possible to prevent private power generation from being used, and to fully consider the cost merit of the user.

In Embodiment 1 of this invention, it is a whole block diagram which shows the structure of an electric hot water supply apparatus. It is a timing chart which shows an example of the amount of heat storage, power consumption, electric power rate, and time at the time of performing solar power generation in the daytime and performing hot water storage operation using midnight power. It is a timing chart which shows an example of the relationship between heat storage amount at the time of performing hot water storage operation by solar power generation, power consumption, an electric power charge, and time. 5 is a flowchart illustrating an example of control executed by a control unit in Embodiment 1 of the present invention. In Embodiment 2 of this invention, it is a flowchart which shows an example of the control performed by the control part. In Embodiment 2 of this invention, it is a timing chart which shows an example of the relationship between heat storage amount at the time of performing hot water storage operation by photovoltaic power generation, power consumption, an electric power charge, and time. In Embodiment 3 of this invention, it is a front view which shows a HEMS controller alone.

Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. In each drawing, common elements are denoted by the same reference numerals, and redundant description is omitted. FIG. 1 is an overall configuration diagram showing a configuration of an electric water heater in Embodiment 1 of the present invention. The electric hot water supply apparatus according to the present embodiment includes a heat pump hot water storage type hot water heater 1 that is operated by commercial electric power and private power generation. Note that in this embodiment, solar power generation is described as an example of one form of private power generation.

  The hot water storage type water heater 1 includes a hot water storage tank 2 that stores hot water, a heat pump unit 3, and a control unit 4 that controls the water heater 1. The heat pump unit 3 includes a heat pump cycle driven by an electric compressor or the like, and can perform a hot water storage operation. In the hot water storage operation, low temperature water is heated using heat in the atmosphere by a heat pump cycle, and the high temperature water is stored in the hot water storage tank 2. The high-temperature water stored in the hot water storage tank 2 is supplied to hot water taps and the like in various places, and is used for heating the bathtub water.

  The control unit 4 controls the operating state of the water heater 1 according to user settings, operating environment, and the like. It is comprised by the apparatus. Various sensors mounted on the water heater 1 are connected to the input side of the control unit 4, and actuators such as pumps and valves mounted on the water heater 1 are connected to the output side of the control unit 4. . The power supply circuit of the water heater 1 is connected to an external power transmission system via the power meter 5. Commercial power (for example, AC 200V) is transmitted to the power transmission system by the power company. The water heater 1 can execute hot water storage operation or the like by purchasing commercial power via the power meter 5.

  Further, the system of the present embodiment includes a solar power generation module 6 capable of performing solar power generation, and an inverter 7 to which power (solar power) generated by the solar power generation module 6 is input. Yes. The inverter 7 has a function of converting the DC voltage input from the photovoltaic power generation module 6 into the same AC voltage as the commercial power, and is connected to the hot water storage type hot water heater 1 and the power meter 5, respectively. The inverter 7 can supply solar power to the hot water storage type hot water heater 1 and operate the hot water storage type hot water heater 1. The inverter 7 supplies power to the power transmission system via the power meter 5 when, for example, the power generation amount (solar power generation amount) of the solar power generation module 6 is larger than the power consumption amount of the hot water storage hot water heater 1. And can sell electricity.

  On the other hand, the control unit 4 of the hot water storage type hot water heater 1 is connected to a HEMS (Home Energy Management System) controller 8 disposed in a house or the like. The HEMS controller 8 is connected to a remote server 10 via the Internet 9 as a communication network, and transmits and stores predetermined information related to household power consumption, power generation, and the like to the server 10. This predetermined information includes, for example, household power consumption, power generation, water supply temperature of the hot water heater 1, outside air temperature, sunshine duration, and the like. The control unit 4 of the water heater 1 performs information communication with the HEMS controller 8 and performs information communication with the server 10 via the HEMS controller 8 and the like, thereby transmitting and receiving the predetermined information as necessary. The resident (user) can confirm the predetermined information by using a television, a personal computer, a dedicated monitor, or the like.

  In the present embodiment, data indicating the relationship between the outside air temperature and the feed water temperature may be stored in the control unit 4 in advance, and the feed water temperature may be estimated from the acquired value of the outside air temperature. The heating capacity of the heat pump unit 3 can be estimated from temperature data as shown in FIG. Moreover, the control part 4 can acquire the electric power charge system information previously stored in the electric power meter 5 or the HEMS controller 8, and can calculate various electric power charges as mentioned later. This power rate system information includes at least the late-night power rate and the power sale rate system. The power charge system information may be input to the HEMS controller 8 or acquired from a power company database via the Internet 9.

(Power selection control)
The present embodiment has the above-described configuration, and next, power selection control executed by the control unit 4 of the water heater 1 will be described. First, the basic concept will be described. In the present embodiment, hot water storage is performed using power that is advantageous in cost among commercial power and solar power by performing the following arithmetic processing (1) to (6). Run the operation.

(1) The power charge when the hot water storage operation is executed using commercial power (midnight power) in the late-night power time period when the power charge is low is calculated as the late-night hot water charge X.
(2) When a hot water storage operation is performed by solar power generation, an electric power charge that would have been available if the electric power used for hot water storage was sold is calculated as a private power generation hot water storage charge Y.
(3) A power selling fee obtained without executing hot water storage operation by solar power generation is calculated as the maximum power selling profit Z.
(4) By subtracting the private power generation hot water storage charge Y from the maximum power sales profit Z, the power sales charge in the case of performing hot water storage operation using solar power generation in the daytime is calculated as the self power generation hot water profit As (= Z -Y).
(5) By subtracting the midnight hot water storage charge X from the maximum power sales profit Z, the power sales charge when solar power generation is performed during the daytime and the hot water storage operation is performed at midnight is calculated as the profit Ac (= Z−X).
(6) Based on the magnitude relationship between the commercial power hot water profit Ac and private power hot water profit As, the power used for the actual hot water storage operation is selected from the commercial power and solar power.

(1: Late night hot water charge X)
Next, each calculation process will be described. FIG. 2 is a timing chart showing an example of the heat storage amount, power consumption, and power rate when solar power generation is performed in the daytime and hot water storage operation is performed using late-night power. In addition, this figure shows the operation example of the water heater under a certain condition, and does not limit the present invention. In addition, the power charges shown in the lower part of FIG. 2 are described with a positive increase in the charge due to power purchase and a negative decrease in the charge due to power sale. As shown in FIG. 2, when using commercial power, for example, midnight power is purchased between 0 o'clock and 4 o'clock included in the midnight power time zone, and the hot water storage operation is executed. FIG. 2 illustrates a state in which a certain amount of hot water is used only during the time zone from 16:00 to 20:00, and no hot water is used during the time zone from 4 o'clock to 16:00 and 20:00 to 24:00. Yes. On the other hand, in the time zone from 8:00 to 20:00, electric power obtained by solar power generation is sold.

  In the calculation process of the late-night hot water storage fee X, first, the hot water use amount (heat amount) of the next day is calculated based on the past history. Further, the amount of natural heat radiation lost from the hot water storage tank 2 due to heat radiation is calculated based on the past history. Based on these calculation results, a required hot water storage amount (heat amount) that needs to be heated by hot water storage operation of midnight power is calculated. The two types of history data are stored in advance in the control unit 4, and the control unit 4 constitutes a hot water supply history storage unit in claim 3. In the next process, the heating capacity and power consumption (in this case, midnight power) of the heat pump unit 3 are estimated based on the required hot water storage amount, the feed water temperature, and the outside air temperature, and converted into a midnight power rate. By this conversion process, the midnight hot water storage fee X when the hot water storage operation is executed using midnight power can be obtained.

  The controller 4 includes first data indicating the relationship between the outside air temperature, the hot water storage temperature difference, and the amount of natural heat radiation, and second data indicating the relationship between the feed water temperature, the outside air temperature difference, and the heating capacity of the heat pump unit 3; Is stored in advance. The control unit can estimate the heating capacity of the heat pump 3 based on the first and second data. The temperature data may be detected by various thermistors (residual hot water temperature thermistor, feed water temperature thermistor, outside air temperature thermistor) mounted on the water heater 1.

  Next, on the assumption of the operation example of FIG. 2, the midnight hot water storage fee X will be specifically calculated. In FIG. 2, the amount of hot water used the next day is set to a constant heat amount of 2.0 kW from 16:00 to 20:00, and the natural heat dissipation amount is set to 0.2 kW. For this reason, if the minimum hot water storage amount (heat storage amount is zero) is reached at 24:00, the required hot water storage amount required by 4 o'clock is 2.2 kW × 4 h = 8.8 kWh, 0.2 kW × 16 h = 12 kWh which is a total of 3.2 kWh. In FIG. 2, the heat pump unit 3 uses 1 kW for heating and has a heating capacity of 3.2 kW, whereas the natural heat dissipation is 0.2 kW. Therefore, the actual heating amount is 3.0 kW ( = 3.2 kW-0.2 kW). Since it takes 4 hours (= 12 kWh / 3.0 kW) to warm 12 kWh of hot water with this heating amount of 3.0 kW, the amount of power used is 1.0 kW × 4 hours = 4.0 kWh. Therefore, if the late-night electricity charge is 10 yen / kWh, the late-night hot water storage charge X is 4.0 kWh × 10 yen / kWh = 40 yen.

(2: Private power generation hot water charge Y)
In the calculation process of the private power generation hot water storage fee Y, first, the hot water use amount (heat amount) of the next day is calculated based on the past history, and the natural heat dissipation amount lost by heat dissipation from the hot water storage tank 2 is calculated based on the past history. . And based on these calculation results, the required hot water storage amount (heat amount) that needs to be heated by the hot water storage operation of solar power is calculated. These processes are almost the same as in the case of the late-night hot water charge X. Further, in this calculation process, the use timing is estimated from the use history of hot water supply, and based on the required hot water storage amount and the use timing estimation result, the hot water use amount (heat amount) required by a predetermined time is calculated. calculate. Next, the heating capacity of the heat pump unit 3 that satisfies the hot water supply usage is predicted based on the daytime daytime water supply temperature, outside air temperature, and the like, and the power consumption is calculated based on the prediction result. Then, if this power consumption is converted into a daytime power rate, a private power generation hot water storage rate Y can be obtained when solar power generation is used to perform a hot water storage operation in the daytime.

  FIG. 3 is a timing chart showing an example of the heat storage amount, power consumption, and power charge when a hot water storage operation is performed by solar power generation. In this figure, solar power generation is executed in the time zone from 8:00 to 20:00, and the hot water storage operation is executed in the time zone from 12:00 to 15:15. In FIG. 3, the amount of hot water used on the next day is set to a constant heat amount of 2.0 kW from 16:00 to 20:00, and the natural heat dissipation amount is set to 0.2 kW. For this reason, if the minimum hot water storage amount (heat storage amount is zero) is reached at 24:00, the required hot water storage amount required by 16:00 is 2.2 kW × 4 h = 8.8 kWh, 0.2 kW × 4 h = 9.6 kWh which is a total of 0.8 kWh. In the above example, the hot water storage operation is set to be completed by 15:15, which is 45 minutes earlier than 16:00 in consideration of variations in hot water supply start time.

  Therefore, the final required hot water storage amount is the natural heat dissipation amount (0.2 kW x 0.75 h = 0.15 kWh) of 45 minutes from 15:15 to 16:00 with respect to the above-mentioned calculation result of 9.6 kWh. The amount is 9.75 kWh (9.6 kWh + 0.15 kWh). In addition, while the power consumption during hot water storage operation is 1 kW and the heating capacity is 3.2 kW, the natural heat dissipation is 0.2 kW, so the actual heating amount is 3.0 kW (3.2 kW-0.2 kW) It becomes. Therefore, 3 hours and 15 minutes (9.75 kWh / 3.0 kW) are required to warm the 9.75 kWh hot water. For this reason, the amount of power consumption during hot water storage operation is 1.0 kW × 3.25 hours = 3.25 kWh. In addition, during the hot water storage operation execution period (12:00 to 15:15, 3.25 hours), the power selling unit price is constant at 15 yen / h. Therefore, the private power generation hot water storage fee Y when the hot water storage operation is performed by solar power generation is 3.25 kWh × 15 yen / h = 48.75 yen. This trial calculation is only an example obtained from the operation example of FIG.

(3: Maximum power selling profit Z of solar power generation)
The maximum power sale profit Z on the next day obtained without executing hot water storage operation by solar power generation is calculated as follows. First, the control part 4 acquires the weather forecast of the next day from a predetermined weather forecast acquisition means. This weather forecast acquisition means includes a HEMS controller 8, a server 10, a predetermined site on the Internet 9, and the like. Then, the control unit 4 calculates a predicted solar power generation amount, which is a predicted value of the solar power generation amount, based on history data indicating the relationship between the weather and the solar power generation amount obtained by the weather forecast. More specifically, the power meter 5 has a function of measuring the power generation amount by the solar power generation module 6 in real time, and transmits the measured power generation amount to the control unit 4.

  The control unit 4 stores the relationship between the amount of photovoltaic power generation acquired in the past and the weather forecast (weather) as history data, and estimates the predicted amount of photovoltaic power generation from the weather forecast based on this history data. Can do. More specifically, the control unit 4 determines the predicted solar power generation amount for the next day based on the fluctuation pattern of the solar power generation amount during the day (FIG. 2) and the history data reflecting the weather forecast for the next day. calculate. Then, the maximum power sale profit Z corresponding to the predicted solar power generation amount is calculated by referring to the data of the power selling fee system based on the calculated predicted solar power generation amount.

  The maximum power sale profit Z is calculated as follows in the power usage example of FIG. Solar power (power generation amount) increases to 2 kW at a constant rate from 8:00 to 12:00 and generates 2 kW, which is a peak in the time from 12:00 to 16:00, and then from 16:00 to 20:00 It decreases to 0 kW at a constant rate in the time zone. For this reason, the total amount of solar power is 2 kW × 4 hours ÷ 2 + 2 kW × 4 hours + 2 kW × 4 hours ÷ 2 = 16 kWh. If the power selling fee system is 15 yen / kWh, the maximum power selling profit Z on the next day is 16 kWh × 15 yen / kWh = 240 yen. This trial calculation is an example when the weather condition is not considered.

(4: Profit at private power storage hot water As)
The private power generation hot water profit As is defined as a power selling fee when the power sale and the hot water storage operation are executed in the daytime by solar power generation. The private power generation hot water saving profit As can be obtained by subtracting the private power generation hot water storage charge Y from the maximum power selling profit Z. When calculated based on the above-mentioned specific example, the profit As at the time of private power generation hot water on the next day is the maximum power sales profit Z (240 yen) at the time of solar power generation-private power generation hot water charge Y (48.75 yen) = 191.25. Calculated as a circle.

(5: Profit Ac when storing commercial power)
The commercial power hot water profit Ac is defined as a power selling fee when the hot water storage operation is performed using late-night power while the solar power generates the power during the daytime. The commercial power hot water storage profit Ac can be obtained by subtracting the midnight hot water storage charge X from the maximum power sales profit Z. When calculated based on the above-described specific example, the commercial power hot water profit Ac on the next day is calculated as the maximum power sales profit Z (240 yen) -midnight hot water storage charge X (40 yen) = 200 yen.

(6: Selection of electric power used for hot water storage operation)
The control unit 4 selects the electric power used for the actual hot water storage operation from the commercial electric power and the solar power based on the magnitude relationship between the commercial power hot water profit Ac and the private power generation hot water profit As. That is, when the commercial power hot water profit Ac is greater than the private power hot water profit As (Ac> As), the hot water storage operation is executed using the commercial power (midnight power) during the midnight power time zone. On the other hand, when the commercial power hot water profit Ac is equal to or less than the private power generation hot water profit As (Ac ≦ As), the hot water storage operation is executed in the daytime using solar power. In the above specific example, since the commercial power hot water profit Ac (200 yen) is larger than the private power generation hot water profit As (191.25 yen), the hot water storage operation by midnight power is selected.

  Further, for example, when the late-night electricity charge becomes 20 yen / kWh, the electricity of 20 yen / h is purchased for 4 hours from 0:00 to 4:00 in FIG. Increases to 4h × 20 yen / h = 80 yen. As a result, the commercial power hot water profit Ac becomes the maximum power selling profit Z (240 yen)-the midnight hot water charge X (80 yen) = 160 yen, which is smaller than the private power generation hot water profit As (191.25 yen). . In this case, the control unit 4 selects solar power generation as the electric power used for the hot water storage operation, and executes hot water storage operation and power sale in the daytime by solar power generation.

[Specific Processing for Realizing Embodiment 1]
Next, specific processing for realizing the system operation will be described. FIG. 4 is a flowchart showing an example of the control executed by the control unit in the first embodiment of the present invention. It is assumed that the routine shown in this figure is executed at a predetermined time or every predetermined time while the water heater 1 is in operation. In the routine shown in FIG. 4, first, in step S100, the weather forecast, temperature environment, and the like for the next day are acquired, and in step S102, the hot water usage amount for the next day is predicted. Next, in step S104, a midnight hot water storage fee X is calculated based on the predicted hot water usage amount and the like, and in step S106, a private power generation hot water storage fee Y is calculated based on the predicted hot water usage amount and the like.

  Next, in step S108, the maximum power sale profit Z of the next day by solar power generation is calculated based on a weather forecast or the like. Then, in step S110, commercial power hot water profit Ac (= Z-X) is calculated, and in step S112 private power hot water profit As (= ZY) is calculated. In addition, it is preferable to perform the process so far at the time when the hot water storage operation by midnight electric power is realizable. Subsequently, in step S114, it is determined whether or not the commercial power hot water profit Ac is greater than the private power generation hot water profit As. If this determination is satisfied, the process proceeds to step S116, where midnight power is used. Execute hot water storage operation. Moreover, when determination of step S114 is not materialized, it transfers to step S118 and performs the hot water storage operation using solar power.

  As described in detail above, according to the present embodiment, hot water storage operation is performed by automatically selecting power that is advantageous in terms of cost from solar power and midnight power, without the user performing an extra selection operation or the like. Can improve the operating cost. Thereby, it is possible to prevent the use of solar power generation even when it is disadvantageous in cost as in the prior art, and to fully consider the cost merit of the user.

  Further, in the present embodiment, since the hot water storage profits As and Ac of the next day can be predicted based on at least the history of hot water supply usage, etc., power that is advantageous in terms of cost is required in advance before the actual hot water storage operation is performed. You can choose. Furthermore, in the present embodiment, it is possible to predict the maximum power sale profit Z obtained by solar power generation on the next day based on at least the weather forecast. Thus, it is possible to more accurately determine power that is advantageous in terms of cost before the actual hot water storage operation is performed.

  In the first embodiment, step S104 in FIG. 4 shows a specific example of the first hot water storage charge calculation means in claims 1 and 3, and step S106 shows a specific example of the second hot water storage charge calculation means. ing. Step S108 shows a specific example of the power sale profit calculation unit, and steps S110 to S114 show a specific example of the power selection unit.

  Moreover, in the said Embodiment 1, in FIG.2, FIG.3 etc., the heating capability of the heat pump unit 3 shall be 3.2 kW, the amount of natural heat radiation shall be 0.2 kW, the power consumption at the time of hot water storage operation shall be 1 kW, and sunlight The case where the peak value of the power generation amount is 2 kW, the late-night power charge is 10 yen / kWh, and the power selling charge is 15 yen / kWh is illustrated. However, the present invention is not limited to this, and these specific numerical values vary depending on the specifications and performance of the water heater 1 and the solar power generation module 6, the late-night power, the power rate system of the power selling fee, and the like. The present invention is not limited to this. Furthermore, in Embodiment 1, although solar power generation shall be used as an example of self-power generation, the self-power generation of this invention is not limited to solar power generation.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. The present embodiment is characterized in that the power consumption in the home is taken into account in the configuration (FIG. 1) substantially the same as that of the first embodiment. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The electric power obtained by the photovoltaic power generation is used by household electric appliances in addition to being sold or supplied to the water heater 1. Household electrical products include those with relatively large power consumption, such as air conditioners and electromagnetic cookers (IH cooking heaters). For this reason, in the present embodiment, in the state where solar power generation is selected as the power for hot water storage operation, when the household power consumption is large, part of the hot water storage operation is executed by midnight power. The specific processing will be described below.

  First, in addition to the water heater 1, the electric product is connected to the inverter 7. Data such as the power consumption, usage state, and usage time zone of each electrical product is transmitted and stored from the power meter 5 to the HEMS controller 8. The control unit 4 of the water heater 1 has a function of acquiring these data as history data from the HEMS controller 8 and predicting the household power consumption on the next day according to the time zone based on the history data. The household power consumption is the sum of the power consumption of all the electric products in use. In the present embodiment, the HEMS controller 8 (which may be the control unit 4 or the power meter 5) constitutes a power history storage unit that stores a history of household power consumption.

  When the solar power is selected as the power for performing the hot water storage operation, the control unit 4 calculates the predicted solar power generation amount for the next day based on the weather forecast or the like in substantially the same manner as in the first embodiment. Moreover, the control part 4 calculates the electric power amount required for boiling the hot water amount which satisfy | fills the above-mentioned required hot water storage amount by daytime hot water storage operation as hot water required electric power amount. Here, if the surplus power obtained by subtracting the domestic power consumption from the predicted solar power generation amount is greater than the required hot water storage power amount, both the home appliances and hot water storage operation are performed by solar power generation. I can cover it. However, when the amount of surplus power is less than or equal to the required amount of hot water storage, if an electric product is covered by solar power generation, there is a risk that the power required for hot water storage operation during the day will be insufficient. Therefore, in this case, the auxiliary hot water storage operation is executed using the late-night power, and the electric power (heat amount) necessary for the daytime hot water storage operation is reduced in advance.

[Specific Processing for Realizing Embodiment 2]
Next, specific processing for realizing the system operation will be described. FIG. 5 is a flowchart showing an example of control executed by the control unit in Embodiment 2 of the present invention. The routine shown in this figure is executed in synchronization with the routine of the first embodiment (FIG. 4). In the routine shown in FIG. 5, first, power selection control is executed in step S200. This electric power selection control performs the same process as the routine of FIG. 4 and selects electric power used for hot water storage operation from midnight electric power and solar electric power. Further, during the power selection control, as described above, the calculation process of the predicted solar power generation amount is executed.

  Next, in step S202, it is determined whether or not hot water storage operation by solar power generation is selected in the power selection control. When this determination is established, the process proceeds to step S204, and the household power consumption is calculated. In step S206, the surplus power amount is calculated by subtracting the household power consumption amount from the predicted solar power generation amount. Next, in step S208, it is determined whether or not the surplus power amount is larger than the required hot water storage power amount. If this determination is satisfied, the process proceeds to step S210. In step S210, daytime hot water storage operation is executed using only solar power generation.

  On the other hand, if the determination in step S208 is not established, the process proceeds to step S212, and a supplementary power amount corresponding to the difference between the required hot water storage amount and the surplus power amount is calculated. In step S214, an auxiliary hot water storage operation is performed using late-night power. The auxiliary hot water storage operation is executed until the amount of hot water (heat amount) corresponding to the amount of supplementary electric power is supplemented. As a result, in the state shifted from step S214 to step S210, the shortage of the predicted solar power generation amount is supplemented by the auxiliary hot water storage operation. I can cover both. On the other hand, if the determination in step S202 is not established, a hot water storage operation is executed using only midnight power in step S216, and this routine is terminated.

  Next, the state at the time of solar power generation will be described with reference to FIG. FIG. 6 is a timing chart showing an example of the relationship between heat storage amount, power consumption, power rate and time when hot water storage operation is executed by solar power generation in the second embodiment of the present invention. In this figure, the heating capacity of the water heater 1, the fluctuation pattern of the hot water supply load, and the like are the same as those in the first embodiment. As shown in FIG. 6, in the time zone from 12:00 to 14:00, 1.5 kW of 2 kW of power obtained by solar power generation is consumed by a load such as an electric product, and the surplus power is 0. It has decreased to 5 kW. In this state, the hot water storage operation requiring 1 kW cannot be executed.

  After 14:00, hot water storage operation becomes possible by reducing the load of electrical products, etc., but when hot water storage operation is started from 14:00, the total time required for hot water storage operation (by 15:15) Of the time required to boil up 9.75 kWh (3.25 hours), only 1.25 hours from 14:00 to 15:15 can be secured. Since the amount of heat obtained by the hot water storage operation for 1.25 hours is 3.75 kWh (= 1.25 h × 3.0 kW), 6 kWh (= 9.75 kWh-3.75 kWh) is insufficient at 14:00. It will be.

  In this case, in the present embodiment, the auxiliary hot water storage operation is executed in the midnight power time zone of the previous day. The target electric energy (heat amount) to be boiled by the auxiliary hot water storage operation is 8 kWh when the target is to finish the auxiliary hot water storage operation by 4 o'clock. The target power amount 8 kWh is obtained by adding the shortage power amount 6 kWh and the natural heat radiation amount 2.0 kWh (0.2 kW × 10 h) from 4 to 14:00.

  According to the present embodiment configured as described above, in addition to the first embodiment, the following effects can be obtained. If solar power generation is likely to cause power shortage, this state can be predicted in advance on the previous day, and an inexpensive hot midnight power can be used to supplement the next day's power shortage to perform auxiliary hot water storage operation. it can. This prevents hot water from running out even when the power consumption of electrical equipment in the home becomes excessive, or when it is attempted to rely on solar power to boil hot water while ignoring the power consumption of each electrical equipment. Therefore, it is not necessary to purchase commercial power in the daytime, and the power cost can be stably suppressed.

  In the second embodiment, the calculation process of the predicted solar power generation amount executed in step S200 in FIG. 5 shows a specific example of the first prediction means in claim 5. Step S204 shows a specific example of the second prediction means, and steps S208, S212, and S214 show specific examples of the auxiliary hot water storage means.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG. The present embodiment is characterized in that in the configuration and control (FIGS. 1 and 5) substantially the same as in the second embodiment, there is provided a predicted value operation means for adjusting the predicted value of household power consumption. It is said. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 7 is a front view showing a single HEMS controller in Embodiment 3 of the present invention. As shown in this figure, the HEMS controller 8 is equipped with a touch panel display 100 (hereinafter simply referred to as a touch panel). The touch panel 100 constitutes a predicted value operation unit that can adjust the predicted value of household power consumption when the user performs a touch operation. The user is configured to select an action schedule for the next day from several types of options displayed on the touch panel 100. Examples of options include whether to go out all day, whether to eat lunch, whether to eat dinner, whether to take a bath at home, and so on.

  The selection result of touch panel 100 is transmitted to control unit 4 of water heater 1. Based on the selection result of the touch panel 100, the control unit 4 adjusts the predicted value of the household power consumption on the next day. More specifically, when the user chooses to go out all day, the power consumption in the home is predicted on the assumption that no product such as an air conditioner is used, except for a product that always operates, such as a refrigerator. In addition, when the user selects lunch or dinner, it is predicted that power consumption by a microwave oven, an IH cooking heater, or the like used for preparing meals in the daytime and evening will not occur. Furthermore, when the user selects no bathing, it is predicted that electric power for boiling hot water is not necessary.

  And these prediction contents are reflected in a prediction value in the process (for example, step S204 in FIG. 5) which estimates household power consumption. Therefore, according to the present embodiment, it is possible to improve the prediction accuracy of the domestic power consumption, and accordingly, it is possible to accurately execute the hot water storage operation and auxiliary hot water storage operation by solar power generation.

  In addition, in the said Embodiment 3, although the case where a predicted value operation means was implement | achieved by the touch panel 100 of the HEMS controller 8 was illustrated, this invention is not restricted to this, For example, the control part 4 of the water heater 1 and the electric power meter 5 are used. Predicted value operating means may be installed.

  In Embodiments 1 to 3, the hot water storage operation is executed using the midnight power when the commercial power hot water profit Ac is greater than the private power hot water profit As (Ac> As), and otherwise ( Ac ≦ As) is configured to execute hot water storage operation using solar power. However, according to the present invention, in addition to this, when both the commercial power hot water profit Ac and the private power generation hot water profit As are negative values, the hot water storage operation is performed using midnight power regardless of the magnitude relationship between the two. It may be configured to execute. According to this configuration, for example, even when solar power generation (power sale) cannot be sufficiently performed due to an abnormality of the solar power generation system or when the power generation amount is not stable, the hot water storage operation is stably performed using midnight power. Can be executed.

1 Hot water storage water heater (hot water heater)
2 Hot water storage tank 3 Heat pump unit 4 Control unit (hot water supply history storage means)
5 Electricity meter 6 Solar power generation module 7 Inverter 8 HEMS controller (weather forecast acquisition means, electric power history storage means)
9 Internet (Meteorological forecast acquisition means)
10 servers (weather forecast acquisition means)

Claims (8)

A water heater that is operated by commercial power and solar power, and that can perform a hot water storage operation that heats low temperature water and stores the high temperature water in a hot water storage tank;
First hot water charge calculation means for calculating an electric charge as a midnight hot water storage charge when the hot water storage operation is executed using commercial power during a midnight electric power hour when the electric charge is cheap;
When the hot water storage operation is executed on the next day by solar power generation, a second hot water charge calculating means for calculating the electric power charge when the power is sold with the amount of electricity as the private power generation hot water storage charge;
A weather forecast acquisition means for acquiring a weather forecast for the next day;
A power sale profit calculating means for calculating a maximum power sale profit which is a power sale fee for the next day obtained without executing the hot water storage operation by solar power generation based on at least the weather forecast ;
The magnitude relationship between the profit at the time of commercial power hot water obtained by subtracting the midnight hot water storage charge from the maximum power sale profit and the profit at the time of private power storage hot water obtained by subtracting the private power generation hot water charge from the maximum power sale profit Based on the power selection means for selecting the power used for the actual hot water storage operation from the commercial power and the photovoltaic power ,
Electric water heater with A water heater that is operated by commercial power and solar power, and that can perform a hot water storage operation that heats low temperature water and stores the high temperature water in a hot water storage tank;
First hot water charge calculation means for calculating an electric charge as a midnight hot water storage charge when the hot water storage operation is executed using commercial power during a midnight electric power hour when the electric charge is cheap;
When the hot water storage operation is executed on the next day by solar power generation, a second hot water charge calculating means for calculating the electric power charge when the power is sold with the amount of electricity as the private power generation hot water storage charge;
A power selling profit calculating means for calculating a power selling fee obtained without executing the hot water storage operation by solar power generation as a maximum power selling profit;
The magnitude relationship between the profit at the time of commercial power hot water obtained by subtracting the midnight hot water storage charge from the maximum power sale profit and the profit at the time of private power storage hot water obtained by subtracting the private power generation hot water charge from the maximum power sale profit Based on the power selection means for selecting the power used for the actual hot water storage operation from the commercial power and the photovoltaic power ,
A weather forecast acquisition means for acquiring a weather forecast for the next day;
First prediction means for calculating a predicted solar power generation amount obtained by solar power generation on the next day based on at least the weather forecast;
Power history storage means for storing a history of power consumption at home;
A second predicting means for predicting the home power consumption of the next day based on the home power consumption history;
In a state where the photovoltaic power generation power is selected by the power selection means, the surplus power amount obtained by subtracting the household power consumption amount from the predicted solar power generation amount is smaller than the required hot water storage power amount required for daytime hot water storage operation. A hot water storage means for generating a hot water amount corresponding to a difference between the surplus power amount and the required hot water storage amount by hot water storage operation in the midnight power time zone,
Electric water heater with Before SL power selecting means, when the commercial power hot water storage at income is greater than income when the self-generation hot-water, the midnight run the hot water storage operation using the commercial power to the power consumption period, when the commercial power hot water storage The electric hot water supply apparatus according to claim 1 or 2 , wherein the hot water storage operation is performed in the daytime using electric power of the solar power generation when the profit is equal to or less than the profit at the time of the private power generation hot water storage. Comprising hot water supply history storage means for storing a history of hot water usage used by the hot water supply,
The first and second hot water storage charge calculation means calculate the predicted hot water use amount for the next day based on at least the history of the hot water use amount, and the electric power necessary to generate the predicted hot water use amount by the hot water storage operation. The electric water heater according to any one of claims 1 to 3, wherein the electric water heater is configured to calculate a charge. Before SL power selling profit calculating means calculates a solar prospective power generation amount obtained by the day after the solar power based at least on the weather forecasts, to calculate the maximum power selling profit the based on the solar prospective power generation amount The electric hot water supply device according to claim 1 or 2, which is configured. A first prediction means for calculating a solar prospective power generation amount obtained by the day after the solar power based on the weather forecast even without low,
Power history storage means for storing a history of power consumption at home;
A second predicting means for predicting the home power consumption of the next day based on the home power consumption history;
In a state where the photovoltaic power generation power is selected by the power selection means, the surplus power amount obtained by subtracting the household power consumption amount from the predicted solar power generation amount is smaller than the required hot water storage power amount required for daytime hot water storage operation. A hot water storage means for generating a hot water amount corresponding to a difference between the surplus power amount and the required hot water storage amount by hot water storage operation in the midnight power time zone,
The electric hot water supply device according to claim 1 , comprising: The electric hot water supply apparatus of Claim 2 or 6 provided with the predicted value operation means in which the operation which adjusts the predicted value of the said household energy consumption estimated by the said 2nd prediction means is possible. The power selection means is configured to execute the hot water storage operation using the commercial power during the midnight power hours when both the commercial power hot water profit and the private power generation hot water profit are negative values. The electric water heater according to any one of claims 1 to 7 .

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