Hot water storage system

Abstract

We provide a hot water supply system that can automatically set whether or not to store hot water during the daytime based on weather forecast information. [Solution] In a hot water storage system (1) configured to be able to perform hot water storage operation using electricity generated by an external solar power generation device (4), the control means sets the time period during which power generation by the solar power generation device is expected to occur as the hot water storage allowance time period, and sets whether or not to store hot water for each unit time within the hot water storage allowance time period based on predetermined unit time weather forecast information obtained from an external server via a communication network.

Description

Technical Field

[0005] ,

[0004] , , ,

[0001] The present invention relates to a domestic hot water storage and supply system that predicts future hot water usage based on past hot water supply records and stores hot water in a storage tank according to this prediction, and particularly to a hot water storage and supply system that can store hot water using electric power generated by a domestic solar power generation device.

Background Art

[0002] Conventionally, a hot water storage and supply system that performs a hot water storage operation of heating hot water and storing it in a storage tank using a heat pump type heat source machine as a heat source, and uses the hot water stored in this storage tank for hot water supply has been widely used. For example, there are types that use inexpensive late-night electricity to store hot water for the next day the previous night, and types that store the amount of heat required for predicted future hot water usage based on past hot water supply records before hot water supply.

[0003] On the other hand, in recent years, the introduction of solar power generation devices to ordinary households has been increasing. The electric power generated by the solar power generation device is supplied to household appliances such as refrigerators, and the surplus electric power can be sold to the outside. However, in the current situation where the selling price of electricity has dropped, it is more economical to use the electric power generated by the solar power generation device within the household (self-consumption) than to sell it. Therefore, in a hot water storage and supply system that stores hot water for the next day the previous night, a configuration that stores hot water using the generated electric power has been proposed.

[0004] For example, in Patent Document 1, based on the acquired weather forecast information for the next day, it is determined the previous night whether hot water can be stored during the day of the next day by receiving power supply from the solar power generation device. If hot water can be stored, a notice of the hot water storage is displayed on a display means, and if hot water cannot be stored, hot water is stored the previous night and it is displayed that hot water cannot be stored during the day.

[0005] Furthermore, Patent Document 2 discloses that, based on the weather forecast information obtained for the following day, it is determined whether the weather is suitable for receiving electricity from a solar power generation device and storing hot water during the designated operating time period of the following day, and depending on this determination, hot water is stored during the daytime, including the adjacent time periods before and after the designated operating time period, or the night before.

[0006] Furthermore, Patent Document 3 discloses a method for predicting the surplus power of a solar power generation system for the following day based on weather information, and adjusting the amount of hot water stored the previous night and the amount of hot water stored during the day the following day according to the predicted value of the surplus power. This prediction of surplus power is repeated at a predetermined cycle. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 7058700 [Patent Document 2] Patent No. 7414689 [Patent Document 3] Patent No. 6830843 [Overview of the project] [Problems that the invention aims to solve]

[0008] The hot water storage systems described in Patent Documents 1 to 3 are configured to store hot water using electricity generated in conjunction with a solar power generation system. However, depending on the combination of the solar power generation system and the hot water storage system, such as when either the solar power generation system or the hot water storage system is installed later, it may be difficult to link the solar power generation system and the hot water storage system.

[0009] Here, a hot water storage system that stores the amount of heat needed for future hot water use, predicted based on past hot water usage data, before use, is highly economical because it stores the right amount of hot water at the right time, minimizing waste. In this hot water storage system, economic efficiency can be further improved by using electricity generated by a solar power generation system for hot water storage. Furthermore, by setting the system to store hot water during the daytime, it is possible to configure it to store hot water using electricity generated by a solar power generation system, even without direct connection to the system.

[0010] However, even in weather conditions where solar power generation is not expected, hot water will still be stored using commercial electricity during the day. This increases heat loss before the stored water is used, leading to a decrease in economic efficiency. Furthermore, switching the setting to store hot water during the day or not depending on the weather requires user intervention, making it impractical.

[0011] Therefore, the present invention aims to provide a hot water storage and supply system that can automatically set whether or not to store hot water during the daytime according to weather forecast information. [Means for solving the problem]

[0012] The hot water storage system of the invention of claim 1 comprises a hot water storage tank for storing hot water, a heat source unit for heating the hot water in the hot water storage tank, a pump for circulating the hot water between the hot water storage tank and the heat source unit, and a control means for controlling a hot water storage operation in which the heat source unit and the pump are driven according to a hot water usage forecast predicted based on past hot water supply performance learned and stored, and the hot water storage operation is configured to be performed using electricity generated by an external solar power generation device, wherein the control means sets the time period during which power generation by the solar power generation device is expected as a hot water storage allowance period, and sets whether or not hot water can be stored for each unit time within the hot water storage allowance period based on weather forecast information for each predetermined unit time obtained from an external server via a communication network.

[0013] According to the above configuration, the hot water storage and supply system automatically sets whether or not to store hot water during the permissible hot water storage period when power generation from an external solar power generation device is expected, in accordance with weather forecast information for each unit of time. As a result, when power generation is expected, storing hot water during the day will increase heat loss, but the use of commercial electricity for hot water storage can be reduced. Also, when the amount of power generated is expected to be small or none, the system can automatically stop storing hot water to suppress heat loss from hot water storage during the day.

[0014] The hot water storage and supply system of claim 2 further comprises a display means for displaying information relating to the hot water storage operation in the invention of claim 1, wherein the control means displays the weather forecast information and whether or not hot water storage is permitted during the permitted hot water storage time period on the display means. With the above configuration, users can be informed of weather forecasts and whether or not hot water storage is possible using electricity generated by the solar power generation system.

[0015] The hot water storage and supply system of claim 3 is characterized in that, in the invention of claim 2, the control means displays the weather forecast information and whether or not hot water storage is permitted for the permitted hot water storage period of the following day on the display means after the permitted hot water storage period for the current day has ended. With the above configuration, users can be informed of the weather forecast for the following day and whether or not hot water storage will be possible using the generated electricity.

[0016] The hot water storage and supply system of the invention of claim 4 is characterized in that, in the invention of claim 1, the control means sets the time period in which sunny weather is continuous, based on the weather forecast information, as the time period in which hot water can be stored, within the hot water storage allowable time period, for each unit time period corresponding to the weather forecast information. According to the above configuration, when sunny weather forecasts are consecutive for each unit of time within the hot water storage allowable time period, the corresponding consecutive time period is set as available for hot water storage, thereby suppressing frequent starting and stopping of the heat source unit. Consequently, the unavoidable startup loss that occurs when the heat source unit cannot efficiently store hot water for a while immediately after starting up can be reduced.

[0017] The hot water storage and supply system of claim 5 is characterized in that, in the invention of any one of claims 1 to 4, the control means acquires the weather forecast information each time the unit time has elapsed and updates the setting of whether or not hot water storage is possible. According to the above configuration, the hot water storage availability during the permitted storage period is updated based on the latest weather forecast information, allowing it to adapt to weather fluctuations and is expected to improve economic efficiency.

[0018] The hot water storage and supply system of the invention of claim 6 is characterized in that, in the invention of claim 5, the control means updates the hot water storage capability setting based on the last acquired weather forecast information if the weather forecast information cannot be acquired. With the above configuration, even if the latest weather forecast information cannot be obtained, the hot water storage capability can be updated based on the last obtained weather forecast information, which is expected to improve economic efficiency.

[0019] The hot water storage and hot water supply system of claim 7 is characterized in that, in the invention of claim 5, when the control means updates the hot water storage feasibility setting for the time period to which the current time belongs within the hot water storage allowable time period, it updates the hot water storage feasibility setting based on the weather forecast information and the hot water storage feasibility setting set for the time period immediately preceding the time period to which the current time belongs. According to the above configuration, the acquired weather forecast information does not include weather forecast information for the time period preceding the current time. However, the setting for whether or not hot water storage is possible for the time period immediately preceding the current time is based on the weather forecast information for that time period. Therefore, it is possible to determine whether or not sunny weather has continued between the time period to which the current time belongs and the time period immediately preceding it, and then set whether or not hot water storage is possible for the time period to which the current time belongs.

Effect of the Invention

[0020] According to the hot water storage and supply system of the present invention, since it is possible to automatically set whether hot water storage during the day according to weather forecast information, hot water can be stored with the power generated without cooperating with the photovoltaic power generation device, reducing the amount of commercial power used. In the case of weather where power generation cannot be expected, it is possible to reduce heat dissipation loss by setting not to perform hot water storage during the day.

Brief Description of the Drawings

[0021] [Figure 1] It is a configuration diagram of the hot water storage and supply system according to an embodiment of the present invention and its surroundings. [Figure 2] It is a configuration diagram of the hot water storage and supply system of FIG. 1. [Figure 3] It is an explanatory diagram of hot water supply usage prediction. [Figure 4] It is an example of display of hot water storage availability setting outside the hot water storage allowable time zone. [Figure 5] It is an example of display of hot water storage availability setting within the hot water storage allowable time zone. [Figure 6] It is a flowchart of hot water storage availability setting. [Figure 7] It is an example of hot water storage availability setting for the first setting target time zone. [Figure 8] It is an example of hot water storage availability setting for the next setting target time zone.

Mode for Carrying Out the Invention

[0022] Hereinafter, the mode for carrying out the present invention will be described based on examples.

Example

[0023] First, the hot water storage and supply system 1 and its peripheral configuration will be described based on FIG. 1. The hot water storage system 1 includes a heat pump type heat source unit as the main heat source unit 10, a hot water storage unit 20, and an auxiliary heat source unit 40. The main heat source unit 10 is connected to the distribution board 2 via a power line 10a. The power line 20a of the hot water storage unit 20 and the power line 40a of the auxiliary heat source unit 40 are connected by plugging the plugs at the ends of the power lines extending from the distribution board 2 to the outdoors into sockets (outdoor outlets 9), respectively. The distribution board 2 distributes commercial power supplied from a commercial power line 3 connected to the commercial power supply and generated power supplied from a solar power generation device 4 to the hot water storage system 1 and household appliances such as refrigerators (not shown).

[0024] The solar power generation system 4 includes a junction box 6 that combines the DC power generated by multiple solar panels 5 receiving sunlight, and a power conditioner 7 that converts the DC power from the junction box 6 into AC power for household use and supplies it to the distribution board 2. A portion of the power supplied from the solar power generation system 4 is consumed domestically by household appliances, and any surplus power that is not consumed domestically is sold to the outside via the commercial power line 3. The hot water storage and hot water supply system 1 is driven by the generated power and commercial power supplied from the distribution board 2, either individually or in combination.

[0025] Next, the hot water storage and supply system 1 will be explained based on Figures 1 and 2. The hot water storage system 1 is configured to store hot water heated by the main heat source unit 10 in a hot water storage tank 21 of the hot water storage unit 20 through a hot water storage operation. The hot water stored in the hot water storage tank 21 is supplied to, for example, a hot water tap 8 via an auxiliary heat source unit 40. The auxiliary heat source unit 40 is, for example, a combustion-type heat source unit, and reheats the hot water supplied from the hot water storage unit 20 according to its temperature, or supplies it to the hot water tap 8 without reheating.

[0026] At the bottom of the hot water storage tank 21, a main heat source supply passage 23 equipped with a pump 22 is connected to supply hot water from the hot water storage tank 21 to the main heat source unit 10. At the top of the hot water storage tank 21, a main heat source return passage 24 is connected to return the hot water heated by the main heat source unit 10 back to the hot water storage tank 21. A switching valve 25 is installed in the middle of the main heat source return passage 24 to switch the flow path of the hot water, and a return branch passage 24a, which branches off from the main heat source return passage 24 by the switching valve 25, is connected to the upstream portion of the main heat source supply passage 23 beyond the pump 22.

[0027] Upstream of the switching valve 25 in the main heat source return passage 24, a return temperature sensor 24b is installed to detect the temperature of the hot water heated by the main heat source 10. For example, if the temperature detected by the return temperature sensor 24b is low immediately after starting up the main heat source 10, the switching valve 25 is switched from the hot water storage tank 21 side to the return branch passage 24a side, and the hot water is circulated without being returned to the hot water storage tank 21 until it can be heated sufficiently.

[0028] A water supply passage 26, indicated by arrow CW, is connected to the bottom of the hot water storage tank 21 to supply tap water. A hot water outlet passage 27 is connected to the top of the hot water storage tank 21 to allow the hot water from the tank 21 to exit the hot water storage unit 20. A water supply branch passage 26a, which branches off from the water supply passage 26, is connected to a mixing valve 28 located in the middle of the hot water outlet passage 27. Multiple hot water temperature sensors 21a to 21d are installed in the hot water storage tank 21 to detect the temperature and amount of hot water stored in the tank 21.

[0029] A water supply temperature sensor 26b is installed in the water supply passage 26 to detect the temperature of the tap water supplied from the water supply passage 26 (water supply temperature). A hot water outlet passage 27 is installed in the hot water outlet passage 27, a hot water storage tank outlet temperature sensor 27b, and a hot water outlet temperature sensor 27c. The hot water outlet flow rate sensor 27a detects the flow rate of hot water from the hot water storage unit 20. The hot water storage tank outlet temperature sensor 27b detects the temperature of the hot water dispensed from the hot water storage tank 21 (hot water storage tank outlet temperature). The hot water outlet temperature sensor 27c detects the temperature of the hot water dispensed from the hot water storage unit 20.

[0030] The hot water outlet passage 27 of the hot water storage unit 20 and the water inlet 40a of the auxiliary heat source unit 40 are connected by a hot water passage 41. The hot water outlet 40b of the auxiliary heat source unit 40 is connected to a hot water supply passage 42 which is connected to a hot water tap 8. The hot water dispensed from the hot water storage unit 20 is supplied to the hot water tap 8 via the auxiliary heat source unit 40, and hot water is supplied from the hot water tap 8 as indicated by the arrow HW.

[0031] The hot water storage unit 20 has a control unit 29 (control means) that controls the hot water storage operation. The control unit 29 drives the pump 22 to circulate hot water between the hot water storage tank 21 and the main heat source unit 10, and stores the hot water heated by the main heat source unit 10 from the top of the hot water storage tank 21. The control unit 29 also adjusts the mixing ratio in the mixing valve 28 to dispense hot water based on the hot water outlet temperature of the hot water storage tank, the water supply temperature, and the hot water flow rate, so that the temperature detected by the hot water outlet temperature sensor 27c becomes, for example, a preset hot water supply set temperature or a predetermined temperature. The predetermined temperature is set so that the auxiliary heat source unit 40 heats the hot water supplied from the hot water storage unit 20 to the hot water supply set temperature and supplies it.

[0032] For example, an operating terminal 30 is installed on the wall of an indoor area such as a kitchen, which is equipped with a display unit that shows information related to hot water supply and hot water storage operation, and is used to set the hot water temperature. This operating terminal 30 is connected to the auxiliary heat source unit 40 in a communicative manner and is configured to supply hot water at the hot water temperature set on the operating terminal 30 to the hot water tap 8. Furthermore, the operating terminal 30 is connected to the control unit 29 of the hot water storage unit 20 in a communicative manner via the auxiliary heat source unit 40, and can perform setting operations related to hot water storage operation. In addition, the operating terminal 30 is connected to an external communication network 34 (Internet) in a communicative manner via, for example, a home gateway device 33 that constitutes a home network. As a result, the control unit 29 can communicate with an external server 35 via the communication network 34.

[0033] Server 35 is installed, for example, by the manufacturer or management company of the hot water storage system 1, and the hot water storage system 1 and the user's mobile terminal 36 (smartphone) are registered with Server 35. The mobile terminal 36 has software installed to display information about the hot water storage system 1. Server 35 and the registered mobile terminal 36 can communicate with each other via the communication network 34.

[0034] The control unit 29 learns and stores hot water usage times, heat usage amounts, etc., as hot water usage records. Based on these past records, it predicts future hot water usage and stores the appropriate amount of hot water at the appropriate time to reduce heat loss based on the predicted future usage. As shown in Figure 3, for example, if the current time is 16:00, it predicts hot water usage for a predetermined period from 1 to 5 hours ahead (from 17:00 to 21:00). If the amount of heat already stored is insufficient, it starts a hot water storage operation to ensure that there is enough heat for hot water supply. At this time, the hot water storage setting temperature is set to the lowest possible temperature that can be supplied at the hot water supply setting temperature, and hot water is stored using a highly efficient hot water storage operation. The hot water storage system 1 has a normal mode in which it performs hot water storage operation considering this heat loss. This normal mode is basically less wasteful and more economical. The prediction of future hot water usage is updated over time. The hot water storage operation ends when the maximum heat storage capacity of the hot water storage tank 21 is reached, or when the amount of heat required for future hot water use has been stored.

[0035] On the other hand, if the user wants to use the electricity generated by the solar power generation system for self-consumption and storage of hot water, they can switch from normal mode to consumption-priority mode by, for example, switching the operating mode on the operation terminal 30. In consumption-priority mode, the control unit 29 sets the time period during which power generation by the solar power generation system 4 is expected as the hot water storage allowance period, and sets the hot water storage temperature for hot water storage operations within the allowance period to its upper limit temperature (for example, 65°C) in order to promote hot water storage. If hot water can be stored using electricity generated during the day, the heat loss until the stored hot water is used will increase, but the amount of commercial electricity used for hot water storage will decrease, which may make it more economical than normal mode.

[0036] In Figure 3, for example, the hot water storage allowance period is set from 10:00 to 15:00. If the current time is 9:00, the hot water usage for 12 hours, from 10:00 to 2:00 (1 to 13 hours ahead), is predicted, and this predicted amount of heat is stored in the hot water storage allowance period. The hot water storage allowance period can be set as follows: for example, 7 hours from 9:00 to 16:00 during the three months centered around the summer solstice, 5 hours from 10:00 to 15:00 during the three months centered around the winter solstice, and 6 hours from 9:00 to 15:00 during other periods. The hot water storage allowance period can be changed as appropriate depending on the season, the amount of sunlight in the installation environment of the solar panel 5, etc., and the period for predicting hot water usage can also be set as appropriate depending on the usage situation.

[0037] In consumption priority mode, the control unit 29 obtains weather forecast information for the installation area of ​​the hot water storage system 1 from the server 35 and sets whether or not to operate the hot water storage system during the daytime based on this weather forecast information. The weather forecast information is weather forecast information for predetermined unit time intervals (for example, hourly weather forecasts from the present to about 24 hours in advance). The installation area is registered with the server 35 at the time of construction of the hot water storage system 1, for example, at the municipal level. The server 35 may collect weather forecast information for the entire country at regular intervals from a weather forecast server, such as the Japan Meteorological Agency, which provides weather forecast information via the communication network 34, or it may collect weather forecast information for the corresponding area when the hot water storage system 1 requests weather forecast information. Whether or not to operate the hot water storage system is set at the same unit time intervals as the weather forecast information during the daytime hot water storage allowance period when power generation from the solar power generation device 4 is expected.

[0038] The control unit 29 displays the weather forecast information for each unit of time within the hot water storage allowance period, and whether hot water storage is permitted or not, for each set unit of time, on the display unit of the operation terminal 30. The control unit 29 also transmits this hourly weather forecast information and hot water storage permission / disability information to the registered mobile terminal 36 via the server 35, so that the hourly weather forecast information and hot water storage permission / disability information can also be displayed on the display unit of the mobile terminal 36.

[0039] The display unit of the operating terminal 30 or the portable terminal 36 displays, for example, as shown in Figure 4, the hourly weather forecast information for the day's hot water storage allowance period and the set hot water storage feasibility as the hot water storage operation schedule. For example, if the current time is in the 12 o'clock hour, the hourly weather forecast information and hot water storage feasibility are displayed for the time period to which the current time belongs within the hot water storage allowance period and for time periods thereafter, as shown in Figure 5, but not for time periods that have already passed. If the current time is past the day's hot water storage allowance period, the hourly weather forecast information and the set hot water storage feasibility for the next day's hot water storage allowance period are displayed.

[0040] Next, the setting of whether or not hot water storage is possible by the control unit 29 will be explained based on the flowchart in Figure 6. In the figure, Si(i=1,2,···) represents a step.

[0041] The control unit 29 starts setting whether hot water storage is permitted or not at each unit time (for example, every hour at 00 minutes past the hour). First, in S1, it obtains hourly weather forecast information for the next 24 hours from the server 35 in order to set whether hot water storage is permitted or not, and then proceeds to S2. Then, in S2, it sets the first target time period for setting whether hot water storage is permitted or not within the permitted hot water storage time period, and then proceeds to S3.

[0042] The length of the set target time period is equal to the unit time, and the hot water storage allowable time period is divided into multiple set target time periods of the same length. If the current time is before the start time of the next hot water storage allowable time period, the set target time period to which that start time belongs is set as the first set target time period. If the current time is within the hot water storage allowable time period, the set target time period to which the current time belongs is set as the first set target time period, and no hot water storage permission setting is made for hot water storage allowable time periods before the current time.

[0043] Next, in S3, it is determined whether the weather forecast for the target time period is sunny or not based on the acquired weather forecast information for each unit time. If the weather forecast for the target time period is cloudy or rainy, or something other than sunny, and the determination in S3 is No, then the process proceeds to S4, where the target time period is set to no hot water storage, and then the process proceeds to S9.

[0044] On the other hand, if the weather forecast for the target time period is sunny, and the result of S3 is Yes, the process proceeds to S5. In S5, based on the acquired hourly weather forecast information, it is determined whether the weather forecast for at least one of the time periods immediately preceding or following the target time period is sunny. This step determines whether sunny weather is continuous within the hot water storage allowable time period. If the result of S5 is Yes, the process proceeds to S8, where the target time period is set to allow hot water storage, and the process proceeds to S9. For example, as shown in Figure 7, if the target time period in the 10 o'clock hour is sunny and the immediately following time period in the 11 o'clock hour is also sunny, this target time period is set to allow hot water storage.

[0045] If the result in S5 in Figure 6 is No, proceed to S6, where it is determined whether the current time falls within the time period set for this configuration. If the result in S6 is Yes, proceed to S7, where it is determined whether the time period immediately preceding the time period set for this configuration was set to allow hot water storage.

[0046] Here, the weather forecast information obtained from server 35 does not include the weather forecast information for the time period immediately preceding the set target time period to which the current time belongs. Therefore, in S7, if the time period immediately following the current set target time period is not sunny, S7 determines whether sunny weather is continuous within the hot water storage allowance time period based on the hot water storage feasibility setting information which reflects the weather forecast information for the time period immediately preceding the current set target time period. If hot water storage is set to be possible, the weather forecast information for that time period will be considered sunny. This is particularly useful when the current time belongs to the last set target time period within the hot water storage allowance time period. Note that if the current set target time period is the set target time period to which the start time of the hot water storage allowance time period belongs, there is no hot water storage feasibility setting for the time period immediately preceding it, so the determination in S7 will be No.

[0047] If the result in S7 is Yes, proceed to S8, where the time period for which this setting is to be configured is set to allow hot water storage, and then proceed to S9. If the result in S6 or S7 is No, proceed to S4, where the period for which this setting is to be configured is set to not allow hot water storage, and then proceed to S9.

[0048] Next, in S9, the next target time period is set, and the process proceeds to S10. The next target time period is set to the time period immediately following the current target time period. Then, in S10, it is determined whether the next target time period is outside the hot water storage allowable time period. This is a step to determine whether the setting of hot water storage permission for the hot water storage allowable time period has been completed. If the determination in S10 is No, the process returns to S3 and sets the hot water storage permission for the next target time period (for example, the 11 o'clock hour as shown in Figure 8) according to the weather forecast information immediately before / after it, repeating this process until the determination in S10 is Yes. If the determination in S10 is Yes, the hot water storage permission setting is completed.

[0049] When the consumption priority mode is set and hot water storage is enabled during the hot water storage allowance period, the control unit 29 predicts future hot water usage based on past hot water usage data that it has learned and memorized, and stores hot water during the period set as the hot water storage allowance period based on this predicted future hot water usage. For example, if the amount of stored hot water is insufficient for the predicted amount of hot water usage, the control unit 29 stores hot water so that the required amount of hot water is stored within the period set as the hot water storage allowance period. At this time, the control unit 29 sets the hot water storage setting temperature for the hot water storage operation to the upper limit of the storage temperature so that the amount of hot water that can be stored in the hot water storage tank 21 is maximized.

[0050] In consumption priority mode, if hot water storage is not permitted during the allowed hot water storage time period, the hot water storage operation is basically not performed. However, even in this case, the control unit 29 stores hot water in a way that reduces heat loss for the required amount of heat, similar to normal mode, based on predictions of future hot water usage based on past hot water supply performance learned and stored.

[0051] Thus, in consumption priority mode, the hot water storage and supply system 1 acquires weather forecast information every unit of time and updates the settings for whether hot water storage is possible during the hot water storage allowance period. This allows the system to operate the hot water storage operation during the time period set as possible within the hot water storage allowance period, in order to promote self-consumption of generated electricity while responding to fluctuations in weather forecast information. Therefore, the hot water storage and supply system 1 can store hot water when power generation from the solar power generation device 4 is expected during the hot water storage allowance period, and can restrict hot water storage without user intervention if power generation from the solar power generation device 4 is not expected due to the weather.

[0052] For example, if the latest weather forecast information cannot be obtained due to a malfunction in the communication network 34, the hot water storage permission / disallowance for each unit time during the hot water storage allowance period will be updated based on the last weather forecast information already obtained. If it becomes impossible to update the hot water storage permission / disallowance because weather forecast information cannot be obtained thereafter, the hot water storage allowance period will be set to no hot water storage, and hot water will be stored as in normal mode.

[0053] The operation and effects of the above-described hot water storage and supply system 1 will be explained. The hot water storage and supply system 1 automatically sets whether or not to store hot water during the permissible hot water storage time period when power generation from the external solar power generation device 4 is expected, in accordance with the acquired hourly weather forecast information. When sufficient power generation is expected, storing hot water during the daytime will increase heat loss, but it will reduce the use of commercial electricity for hot water storage. Also, when the amount of power generated is expected to be small or none, the system will automatically set not to store hot water, thereby suppressing heat loss due to hot water storage during the daytime.

[0054] The hot water storage and supply system 1 displays weather forecast information and whether hot water storage is possible during the permitted hot water storage period on the display units of the operation terminal 30 and the portable terminal 36, which are used to display information related to hot water storage operation. This allows the user to be informed of the weather forecast and whether hot water storage using electricity generated by the solar power generation device 4 is possible. Furthermore, after the permitted hot water storage period for the day has ended, the display unit will show the weather forecast information and whether hot water storage is possible for the permitted hot water storage period of the following day, so that the user can be informed of the weather forecast information for the following day and whether hot water storage using generated electricity is possible.

[0055] The hot water storage and supply system 1 sets the time period corresponding to the weather forecast information within the allowable hot water storage time period as the time period during which sunny weather is continuous, based on the weather forecast information. Since the system sets the corresponding continuous time period as hot water storage possible when sunny weather is continuous in the weather forecast information for each unit period, it is possible to suppress frequent starting and stopping of the main heat source unit 10. Accordingly, it is possible to reduce the unavoidable startup loss from immediately after the main heat source unit 10 starts up until it can efficiently store hot water.

[0056] The hot water storage and supply system 1 acquires weather forecast information each time a unit of time has elapsed, and updates the hot water storage availability setting for the permitted hot water storage period based on this latest weather forecast information. This allows the hot water storage availability to be adjusted to weather fluctuations, which is expected to improve economic efficiency. Furthermore, even if weather forecast information cannot be acquired, the hot water storage availability setting is updated based on the last acquired weather forecast information, which is expected to improve economic efficiency when there are no weather fluctuations.

[0057] The hot water storage and supply system 1 updates the hot water storage availability setting for the time period to which the current time belongs within the allowable hot water storage time period, based on weather forecast information and the hot water storage availability setting that was set for the time period immediately preceding the current time period. The acquired weather forecast information does not include weather forecast information prior to the current time, but the hot water storage availability setting for the time period immediately preceding the current time period reflects the weather forecast information for that time period. Therefore, it is possible to determine whether sunny weather has continued between the time period to which the current time belongs and the time period immediately preceding it, and set the hot water storage availability setting for the time period to which the current time belongs.

[0058] Furthermore, those skilled in the art can implement the present invention in various forms with modifications to the above embodiments without departing from the spirit of the invention, and the present invention encompasses such modifications. [Explanation of symbols]

[0059] 1: Hot water storage and supply system 2: Distribution board 3: Commercial power lines 4: Solar power generation equipment 5: Solar panels 6: Junction box 7: Power Conditioner 8: Hot water tap 9: Outdoor electrical outlet 10: Main heat source machine (heat source machine) 20: Hot water storage unit 21: Hot water storage tank 21a~21d: Hot water storage temperature sensor 22: Pump 23: Passage to heat source unit 24: Heat source return passage 24a: Return branch passage 24b: Return temperature sensor 25: Switching valve 26:Water supply passage 26a: Water supply branching passage 26b: Water supply temperature sensor 27: Hot spring access passage 27a: Hot water flow sensor 27b: Hot water storage tank outlet temperature sensor 27c: Hot water temperature sensor 28: Mixing valve 29: Control unit (control means) 30: Operating terminal 34: Communication Network 35: Server 36: Mobile devices 40:Auxiliary heat source machine 41: Hot water passage 42: Hot water supply passage

Claims

1. A hot water storage system comprising a hot water storage tank for storing hot water, a heat source unit for heating the hot water in the storage tank, a pump for circulating the hot water between the storage tank and the heat source unit, and control means for controlling a hot water storage operation that drives the heat source unit and the pump to store hot water in the storage tank according to a hot water usage forecast predicted based on learned and memorized past hot water supply performance, wherein the hot water storage operation is configured to be performed using electricity generated by an external solar power generation device, The hot water storage and supply system is characterized in that the control means sets the time period during which power generation is expected from the solar power generation device as the hot water storage allowable time period, and sets whether or not to store hot water for each unit time within the hot water storage allowable time period based on predetermined unit time weather forecast information obtained from an external server via a communication network.

2. The system further includes a display means for displaying information related to the hot water storage operation, The hot water storage and supply system according to claim 1, characterized in that the control means displays the weather forecast information and whether or not hot water storage is possible during the hot water storage allowance period on the display means.

3. The hot water storage and supply system according to claim 2, characterized in that the control means displays the weather forecast information and whether or not hot water storage is permitted for the permitted hot water storage period of the following day on the display means after the permitted hot water storage period for the current day has ended.

4. The hot water storage and supply system according to claim 1, characterized in that the control means sets the time period for each unit time corresponding to the weather forecast information within the hot water storage allowable time period, and based on the weather forecast information, the time period in which sunny weather continues as the time period in which hot water can be stored.

5. The hot water storage and supply system according to any one of claims 1 to 4, characterized in that the control means acquires the weather forecast information each time the unit time has elapsed and updates the setting of whether or not hot water storage is possible.

6. The hot water storage and supply system according to claim 5, characterized in that, if the control means cannot obtain the weather forecast information, it updates the hot water storage capability setting based on the last obtained weather forecast information.

7. The hot water storage and hot water supply system according to claim 5, characterized in that when the control means updates the hot water storage feasibility setting for the time period to which the current time belongs within the hot water storage allowable time period, it updates the hot water storage feasibility setting based on the weather forecast information and the hot water storage feasibility setting set for the time period immediately preceding the time period to which the current time belongs.

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