Hot water storage system

Abstract

This hot water supply system reduces the startup loss of the heat source unit and allows for hot water storage using surplus electricity from solar power generation. [Solution] The hot water storage system (1) includes a hot water storage tank (21), a heat source unit (10) that heats the hot water in the hot water storage tank, a pump (22) that circulates the hot water between the hot water storage tank and the heat source unit, and a control means (29) that controls the hot water storage operation to drive the heat source unit and the pump to store hot water. The control means starts the hot water storage operation when the start condition of the heat source unit is met, and stops the hot water storage operation when the stop condition of the heat source unit is met. The start condition is met when the amount of heat in the hot water storage tank is insufficient to meet the first amount of heat obtained by summing the predicted heat amounts for a predetermined first period while the heat source unit is stopped, and the stop condition is met when the amount of heat in the hot water storage tank is equal to or greater than the second amount of heat obtained by summing the predicted heat amounts for a second period which is longer than the first period.

Description

Technical Field

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

Background Art

[0002] Conventionally, a hot water storage supply system that performs a hot water storage operation of heating hot water and storing it in a hot water storage tank using a heat pump type heat source machine as a heat source machine, and uses the hot water stored in this hot water 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 is used.

[0003] On the other hand, in recent years, the introduction of solar power generation devices into 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 electricity price 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, it is desired to store hot water using the generated electric power.

[0004] Therefore, for example, in Patent Document 1, based on the stored hot water supply records, the first time in the time period when surplus electric power is predicted, the hot water supply start time, and the amount of heat used during the period until the first time are specified, and when the first time arrives, it is disclosed to preferentially use surplus electric power to store hot water.

[0005] Also, in Patent Document 2, in the stored hot water supply records, the amount of heat used when hot water supply is continuous is grouped as a hot water supply group based on whether hot water can be stored, and it is disclosed to set the start time of the hot water storage operation so that the hot water storage amount is larger than the amount of heat predicted based on this hot water supply group.

Prior Art Documents

[0006] [Patent Document 1] Patent No. 6539572 [Patent Document 2] Patent No. 5084807 [Overview of the project] [Problems that the invention aims to solve]

[0007] The hot water storage system described in Patent Document 1 is configured to work in conjunction with a solar power generation system to store the power generation history for each time period and to preferentially use surplus power for hot water storage during times when surplus power is expected. 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 coordinate the solar power generation system and the hot water storage system.

[0008] Furthermore, in Patent Document 2, since hot water storage is started based on the hot water supply group, once the storage of hot water corresponding to one hot water supply group is completed, the heat pump type heat source unit stops, and after some time has elapsed, the storage of hot water for the next hot water supply group begins. As a result, there is a risk that the heat source unit will repeatedly start and stop, and since this heat source unit is a heat pump type, it cannot store hot water efficiently for a while immediately after starting, making startup losses unavoidable.

[0009] Therefore, the present invention aims to provide a hot water supply system that reduces the startup loss of the heat source unit and can store hot water using surplus electricity from solar power generation. [Means for solving the problem]

[0010] The hot water storage system according to 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 the hot water storage operation to drive the heat source unit and the pump to store hot water in the hot water storage tank, wherein the control means predicts the amount of heat required for future hot water supply as a predicted heat amount for each time period divided into predetermined unit time intervals based on learned and stored hot water supply records, and starts the heat source unit when storing hot water based on the predicted heat amount. The hot water storage operation is started when the condition for starting is met, and the hot water storage operation is terminated when the stop condition for stopping the heat source unit is met. The start condition is met when the amount of heat in the hot water storage tank is insufficient to meet the first heat amount, which is the sum of the predicted heat amounts for the first period, from the next time period including the current time to a predetermined time period after that, while the heat source unit is stopped. The stop condition is met when the amount of heat in the hot water storage tank is equal to or greater than the second heat amount, which is the sum of the predicted heat amounts for the second period, which is longer than the first period.

[0011] According to the above configuration, the hot water storage and supply system stores hot water based on the predicted heat amount for each time period predicted based on past hot water supply performance. When the start condition for the heat source unit is met, the hot water storage operation begins, and when the stop condition for the heat source unit is met, the hot water storage operation ends. The start condition is determined based on the first heat amount, which is the sum of the predicted heat amounts for a predetermined length of first period predicted while the heat source unit is stopped. The stop condition is determined based on the second heat amount, which is the sum of the predicted heat amounts for a second period that is longer than the first period. Therefore, the cases in which the second heat amount for the stop condition is greater than the first heat amount for the start condition increase, and the frequent starting and stopping of the heat source unit can be suppressed. Consequently, the unavoidable start loss that occurs when the heat source unit cannot store hot water efficiently for a while immediately after starting can be reduced, and the economic efficiency of the hot water storage operation can be improved.

[0012] The hot water storage and supply system of the invention of claim 2 is characterized in that, in the invention of claim 1, the hot water storage operation is capable of storing hot water using electricity generated by an external solar power generation device, the control means has a consumption priority mode that sets the time period when power generation is expected to occur as a hot water storage promotion time period in order to self-consume the generated electricity, and in the consumption priority mode, when the current time is within the hot water storage promotion time period the first period is set to be longer than when the current time is outside the hot water storage promotion time period. With the above configuration, in consumption-priority mode, the first heat quantity can be increased, making it easier to meet the startup conditions for the heat source unit. Consequently, the opportunities to use the generated electricity for hot water storage operation increase, improving the economic efficiency of hot water storage operation.

[0013] The hot water storage system of the invention of claim 3 is characterized in that, in the invention of claim 2, the control means sets the hot water storage temperature for the hot water storage operation to a predetermined upper limit temperature in the consumption priority mode, and sets the second period to be longer when the current time is within the hot water storage promotion period than when the current time is outside the hot water storage promotion period. With the above configuration, in consumption-priority mode, the second heat quantity can be increased during the hot water storage promotion period, thereby increasing the amount of heat stored in the hot water storage tank. Consequently, the amount of heat stored increases during the period when power generation is expected, and the use of commercial electricity decreases, thus improving the economic efficiency of hot water storage operation.

[0014] The hot water storage and supply system of the invention of claim 4 is characterized in that, in the invention of claim 3, the control means sets a hot water storage restriction period immediately before the hot water storage promotion period in the consumption priority mode, and sets the second period to be shorter than when the current time is outside the hot water storage promotion period and outside the hot water storage restriction period if the current time is within the hot water storage restriction period. According to the above configuration, in the hot water storage restriction period immediately preceding the hot water storage promotion period, the second period is shorter than in other periods, making it easier to meet the stop condition and limit the amount of heat stored in the hot water storage tank. Consequently, when the hot water storage promotion period begins, the start condition is more easily met, and hot water storage can be promoted during the hot water storage promotion period.

[0015] The hot water storage and supply system of the invention of claim 5 is characterized in that, in the invention of claim 2 or 3, the control means normally sets the output of the heat source unit during hot water storage operation based on the first heat quantity, and sets only the output of the heat source unit during hot water storage operation during the hot water storage promotion time period of the consumption priority mode based on the second heat quantity. According to the above configuration, the output of the heat source unit is set according to the amount of heat to be stored during the hot water storage promotion period. Therefore, by increasing the output of the heat source unit during the hot water storage promotion period, it is possible to promote self-consumption of the generated electricity, and the use of commercial electricity is reduced, thereby improving the economic efficiency of hot water storage operation. [Effects of the Invention]

[0016] According to the hot water storage and supply system of the present invention, the starting loss of the heat source unit is reduced, and hot water can be stored using surplus electricity from solar power generation, thereby improving the economic efficiency of hot water storage operation. [Brief explanation of the drawing]

[0017] [Figure 1] This is a diagram showing the configuration of a hot water storage and supply system and its surroundings according to an embodiment of the present invention. [Figure 2] Figure 1 is a diagram illustrating the configuration of the hot water storage and supply system. [Figure 3] This diagram shows an example of hot water usage forecasts and settings for the first period. [Figure 4] This diagram shows an example of hot water usage forecasts and settings for the second period. [Figure 5] This is a flowchart for determining when a system will start. [Figure 6] This is a flowchart for controlling the hot water storage operation. [Figure 7] This is the second heat quantity calculation flowchart.

Embodiments for Carrying out the Invention

[0018] Hereinafter, embodiments for carrying out the present invention will be described based on examples.

Examples

[0019] First, the hot water storage and supply system 1 and its peripheral configuration will be described based on FIG. 1. The hot water storage and supply system 1 includes a heat pump type heat source machine as the main heat source machine 10 (heat source machine), a hot water storage unit 20, and an auxiliary heat source machine 40. The main heat source machine 10 is connected to the distribution board 2 via the power line 10a. The power lines 20a of the hot water storage unit 20 and the power lines 40a of the auxiliary heat source machine 40 are respectively connected by inserting the plugs at their tips into the sockets (outdoor outlet 9) at the tips of the power lines extending from the distribution board 2 to the outside. The distribution board 2 distributes the commercial power supplied from the commercial power line 3 connected to the commercial power source and the generated power supplied from the solar power generation device 4 to the hot water storage and supply system 1 and household appliances such as a refrigerator (not shown).

[0020] The solar power generation device 4 includes a junction box 6 that collects the DC power generated by a plurality of solar panels 5 receiving sunlight, and a power conditioner 7 that converts the DC power from the junction box 6 into household AC power and supplies it to the distribution board 2. A part of the power supplied from the solar power generation device 4 is consumed by the household appliances, etc., and the surplus power that is not consumed is sold to the outside via the commercial power line 3. The hot water storage and supply system 1 is driven using the generated power and commercial power supplied from the distribution board 2 separately or in combination.

[0021] Next, the hot water storage and supply system 1 will be described based on FIGS. 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The control unit 29 learns and stores hot water usage times, heat usage amounts, etc., as hot water usage records. Then, as shown in Figure 3, for example, based on these past hot water usage records, it predicts future hot water usage as predicted heat amounts (hot water supply, bath filling) for each time period divided into predetermined unit time intervals, and controls the hot water storage operation based on these predicted heat amounts. The hot water storage system 1 has a normal mode that stores the appropriate amount of hot water at the appropriate time while suppressing heat loss from the hot water storage tank 21 and startup loss from the main heat source unit 10. This normal mode is basically less wasteful and more economical.

[0031] On the other hand, if the user wants to use the electricity generated by the solar power generation device 4 for self-consumption and store it as hot water, they can switch from normal mode to consumption priority mode by switching the operating mode on the user's operation terminal 30. In consumption priority mode, the control unit 29 sets the daytime hours when power generation is expected to be high as the hot water storage promotion time period in order to promote self-consumption of the electricity generated by the solar power generation device 4. Then, immediately before the hot water storage promotion time period, it sets a hot water storage restriction time period of a predetermined length (for example, 4 hours). Whether or not hot water can be stored during the hot water storage promotion time period is determined by the control unit 29 based on weather forecast information obtained from the server 35. Then, during the hot water storage promotion time period set to allow hot water storage, hot water is stored based on the predicted amount of heat for predicted future hot water usage.

[0032] The hot water storage promotion time can be set as follows: for example, 7 hours from 9am to 4pm during the three months centered around the summer solstice, 5 hours from 10am to 3pm during the three months centered around the winter solstice, and 6 hours from 9am to 3pm during other periods. In Figure 3, the hot water storage promotion time is set from 10am to 3pm, and the hot water storage restriction time is set from 6am to 10am before the start time of 10am. The hot water storage promotion time 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 usage conditions, etc.

[0033] In consumption priority mode, the control unit 29 sets the hot water storage temperature during hot water storage operation within the hot water storage promotion time period to its upper limit temperature (e.g., 65°C). If hot water can be stored using electricity generated during the day, the heat loss from the stored water until it 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.

[0034] To enable hot water storage using the generated electricity, the control unit 29 obtains weather forecast information for the installation area of ​​the hot water storage and supply system 1 from the server 35 and sets whether hot water storage is possible during the hot water storage promotion time based on this weather forecast information. The weather forecast information is weather forecast information for predetermined unit time intervals (for example, hourly weather forecast information from the present to about 24 hours ahead). The installation area is registered with the server 35 at the time of construction of the hot water storage and supply 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 that 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 and supply system 1 requests weather forecast information. During the daytime hot water storage promotion time interval when power generation from the solar power generation device 4 is expected, hot water storage is set to be possible if sunny weather is continuously predicted in the hourly weather forecast.

[0035] The control unit 29 displays the weather forecast information for each unit of time during the hot water storage promotion period, and whether hot water storage is possible 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 feasibility information to the registered mobile terminal 36 via the server 35, and the hourly weather forecast information and hot water storage feasibility information can also be displayed on the display unit of the mobile terminal 36. For the sake of simplicity, the following explanation assumes that the entire duration of the hot water storage promotion period is set to allow hot water storage.

[0036] In the case of the predicted heat quantity shown in Figure 3, the control unit 29 sets a predetermined first period (normal first period) A1 of a predetermined length (3 hours) from one hour to four hours ahead (from 5 PM to 8 PM) in normal mode, for example, when the current time is 4 PM. Then, it calculates the first heat quantity by summing up the predicted heat quantities for this normal first period A1.

[0037] Furthermore, in consumption priority mode, if the current time is, for example, 10:00 AM within the hot water storage promotion time period, the control unit 29 sets a first period (extended first period) A2 that is longer than usual, from one hour ahead to one hour before the start of the hot water storage promotion time period the next day (from 11:00 AM to 9:00 AM the next day). Then, it calculates the first heat quantity by summing the predicted heat quantities for this extended first period A2. On the other hand, even in consumption priority mode, if the current time is, for example, 7:00 AM outside the hot water storage promotion time period, it sets a first period A3 of the normal length (from 8:00 AM to 11:00 AM), similar to normal mode, and calculates the first heat quantity by summing the predicted heat quantities for that period.

[0038] The control unit 29 calculates a second heat quantity, which is the target value for the amount of heat stored in the hot water storage tank 21, at predetermined intervals (for example, every hour), based on predictions of future hot water usage. As shown in Figure 4, in normal mode, if the current time is, for example, 16:00, the control unit 29 sets a second period (normal second period) B1 of a predetermined length from 1 hour to 8 hours ahead (from 17:00 to 24:00), and calculates the second heat quantity by summing the predicted heat quantities for this second period B1. In normal mode, the normal second period is set regardless of the time of day.

[0039] On the other hand, in consumption priority mode, if the current time is, for example, 10:00 within the hot water storage promotion time, the control unit 29 sets a second period (extended second period) B2 that is longer than usual, from one hour ahead to one hour before the start of the hot water storage promotion time the next day (from 11:00 to 9:00 the next day), and calculates the second heat quantity by summing the predicted heat quantities for that period. Also, in consumption priority mode, if the current time is, for example, 7:00 within the hot water storage restriction time, it sets a second period (shortened second period) B3 that is shorter than usual, from one hour ahead to four hours ahead (from 8:00 to 11:00), and calculates the second heat quantity by summing the predicted heat quantities for that period. And, in consumption priority mode, if the current time is, for example, 16:00 outside both the hot water storage promotion time and the hot water storage restriction time, it sets the normal second period B4 from one hour ahead to eight hours ahead (from 17:00 to 24:00), similar to normal mode, and calculates the second heat quantity by summing the predicted heat quantities for that period.

[0040] Next, the startup determination of the main heat source unit 10 by the control unit 29 will be explained based on the flowchart in Figure 5. In the figure, Si(i=1,2,···) represents a step.

[0041] When the startup determination is initiated, the first step is to determine in S1 whether the current operating mode is normal mode. If the determination in S1 is Yes (normal mode), the process proceeds to S2, where a normal first period of a predetermined length is set, and then the process proceeds to S5. On the other hand, if the determination in S1 is No (consumption priority mode), the process proceeds to S3, where the process determines whether the current time is within the hot water storage promotion time period. If the determination in S3 is No, the process proceeds to S2, where a normal first period is set, and then the process proceeds to S5. If the determination in S3 is Yes, the process proceeds to S4, where a first period longer than usual (extended) is set, and then the process proceeds to S5.

[0042] Next, in S5, the first heat quantity for the first period is calculated from the predicted heat quantity based on the hot water supply record, and the process proceeds to S6. Then, in S6, the amount of heat (storage heat quantity) of the hot water currently stored in the hot water storage tank 21 is obtained, and the process proceeds to S7.

[0043] Next, in S7, it is determined whether the startup conditions have been met. This step determines whether the current amount of stored hot water heat in the hot water storage tank 21 is insufficient compared to the first heat quantity. For example, if the amount obtained by adding the minimum operating heat quantity of the main heat source unit 10 to the current amount of stored hot water heat is small compared to the first heat quantity, it is determined that the startup conditions have been met. The minimum operating heat quantity is, for example, an amount of heat calculated based on a heat quantity pre-set in the main heat source unit 10 or the hot water storage set temperature, such that the benefit of starting the main heat source unit 10 outweighs the startup loss.

[0044] If the result in S7 is Yes, proceed to S8, where the main heat source unit 10 and pump 22 are started to begin hot water storage operation, and the startup check is terminated. If the result in S7 is No, the startup check is terminated without starting hot water storage operation.

[0045] As described above, the first period is extended when the operating mode is consumption priority mode and the current time falls within the hot water storage promotion period. This increases the first heat quantity, which is the sum of the predicted heat quantities within the first period, making it easier to meet the startup conditions and increasing the opportunities to start hot water storage operation during the hot water storage promotion period.

[0046] The control unit 29 controls the hot water storage operation, which is started when the start conditions for the main heat source unit 10 are met, and terminates the hot water storage operation when the stop conditions for the main heat source unit 10 are met. This hot water storage operation control will be explained based on the flowchart in Figure 6.

[0047] When hot water storage operation control is started, in S11 it is determined whether the operating mode is normal mode. If the determination in S11 is Yes (normal mode), proceed to S12, where the first heat quantity is obtained and proceed to S13. Next, in S13, the hot water storage temperature is set based on the first heat quantity and proceed to S14. Then, in S14, the output of the main heat source unit 10 is set based on the first heat quantity and proceed to S15. In S13 and S14, the hot water storage temperature and the output of the main heat source unit 10 are set so that hot water can be stored with high-efficiency hot water storage operation. Next, in S15, the second heat quantity is obtained and proceed to S20.

[0048] On the other hand, if the determination in S11 is No (consumption priority mode), the process proceeds to S16, where the second heat quantity is obtained and the process proceeds to S17. In S17, it is determined whether the current time is within the hot water storage promotion time period. If the determination in S17 is Yes, the process proceeds to S18, where the hot water storage temperature is set to the upper limit temperature and the process proceeds to S19. In S19, the output of the main heat source unit 10 is set based on the second heat quantity and the process proceeds to S20.

[0049] Next, in S20, the current amount of stored hot water is acquired and the process proceeds to S21, where it is determined whether the stop condition for the main heat source unit 10 has been met. The stop condition is met when the amount of stored hot water in the storage tank 21 is equal to or greater than the second heat quantity, which is the sum of the predicted heat quantities for the second period. However, the success or failure may also be determined based on the heat quantity obtained by adding a correction heat quantity to the second heat quantity, for example, taking into account the minimum detectable amount of stored hot water or heat loss. If the determination in S21 is No, the process returns to S15. If the determination in S21 is Yes, the process proceeds to S22, where the main heat source unit 10 and the pump 22 are stopped to end the hot water storage operation and terminate the hot water storage operation control.

[0050] The second heat quantity obtained in S15 or S17 is calculated by the control unit 29 at predetermined intervals, regardless of whether the hot water storage operation is running or stopped. The calculation of this second heat quantity will be explained based on the flowchart in Figure 7.

[0051] When the calculation of the second heat quantity begins, the system first determines in S31 whether the current operating mode is the normal mode. If the determination in S31 is Yes (normal mode), the system proceeds to S32, where the normal second period is set, and then proceeds to S37.

[0052] If the result of S31 is No (consumption priority mode), proceed to S33, where it is determined whether the current time is within the hot water storage promotion time period. If the result of S33 is Yes, proceed to S34, where a second period longer than usual (extended) is set and proceed to S37. On the other hand, if the result of S33 is No, proceed to S35, where it is determined whether the current time is within the hot water storage restriction time period. If the result of S35 is Yes, proceed to S36, where a second period shorter than usual (shortened) is set and proceed to S37. If the result of S35 is No, proceed to S32, where the normal second period is set and proceed to S37.

[0053] Next, in S37, the second heat quantity is calculated by summing the predicted heat quantities for the second period, which are set based on the operating mode and the current time, and the calculation of the second heat quantity is completed. In normal mode, a longer period than the first period is set as the normal second period. In consumption priority mode, depending on the time period to which the current time belongs, a longer second period than usual is set if it is within the hot water storage promotion period, a shorter second period than usual is set if it is within the hot water storage restriction period, and a normal second period is set in the same way as in normal mode for all other time periods.

[0054] In the consumption-priority mode's hot water storage promotion time, a longer-than-usual second period is set, allowing for a larger second heat output and enabling the storage of more heat during this time. By using the generated electricity for self-consumption and storing hot water, the amount of commercial electricity used for hot water storage decreases, thus improving the economic efficiency of hot water storage operation even with increased heat loss.

[0055] In the consumption-priority mode, a shorter second period is set during the hot water storage restriction time, allowing for a smaller second heat output and thus reducing the amount of heat stored during this period. By limiting the amount of heat stored immediately before the hot water storage promotion time, the electricity generated during the hot water storage promotion time is consumed internally for storage, reducing the amount of commercial electricity used for hot water storage. This improves the economic efficiency of hot water storage operation, even if heat loss increases.

[0056] In consumption-priority mode, outside of the hot water storage promotion time and hot water storage restriction time, or in normal mode, the second period is longer than the first period, so in most cases the second heat quantity is greater than the first heat quantity. Then, the hot water storage operation continues until the stop condition based on the second heat quantity is met, so the repeated starting and stopping of the main heat source unit 10 can be suppressed and starting losses can be reduced. In addition, in any operating mode, the hot water storage operation ends when the maximum amount of hot water that can be stored in the hot water storage tank 21 is reached.

[0057] 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 predicts the amount of heat for each time period divided into predetermined unit time intervals based on past hot water supply performance. When storing hot water based on the predicted heat amount, the hot water storage operation starts when the start condition for the main heat source unit 10 is met, and ends when the stop condition for the main heat source unit 10 is met. The start condition is determined based on the first heat amount, which is the sum of the predicted heat amounts for a first period of a predetermined length predicted while the main heat source unit 10 is stopped. The stop condition is determined based on the second heat amount, which is the sum of the predicted heat amounts for a second period that is longer than the first period. Therefore, the cases in which the second heat amount for the stop condition is greater than the first heat amount for the start condition increase, and the frequent starting / stopping of the main heat source unit 10 can be suppressed. Consequently, the unavoidable start loss that occurs when the main heat source unit 10 cannot store hot water efficiently for a while immediately after starting can be reduced, and the economic efficiency of the hot water storage operation can be improved.

[0058] During hot water storage operation, it is possible to use electricity generated by the external solar power generation device 4. The control unit 29 has a consumption priority mode that sets the time period when power generation is expected to occur as the hot water storage promotion time period in order to self-consume the electricity generated by the solar power generation device 4. In this consumption priority mode, if the current time is within the hot water storage promotion time period, the first period is set to be longer than if the current time is outside the hot water storage promotion time period. As a result, in consumption priority mode, the first heat quantity can be increased, making it easier to meet the startup conditions of the main heat source unit 10. Therefore, the opportunities to perform hot water storage operation using electricity generated by the solar power generation device 4 increase, and the economic efficiency of hot water storage operation can be improved.

[0059] In consumption priority mode, the control unit 29 sets the hot water storage temperature for hot water storage operation to a predetermined upper limit temperature, and if the current time is within the hot water storage promotion time period, it sets the second period to be longer than if the current time is outside the hot water storage promotion time period. As a result, in consumption priority mode, the second heat quantity can be increased during the hot water storage promotion time period, and the amount of heat stored in the hot water storage tank 21 can be increased. Consequently, the amount of heat stored during the time when power generation is expected increases, and the use of commercial electricity for hot water storage decreases, thereby improving the economic efficiency of hot water storage operation.

[0060] In consumption priority mode, the control unit 29 sets a hot water storage restriction period immediately before the hot water storage promotion period, and if the current time is within the hot water storage restriction period, it sets the second period to be shorter than if the current time is outside both the hot water storage promotion period and the hot water storage restriction period. Since the second period is shorter during the hot water storage restriction period immediately before the hot water storage promotion period than during other time periods, it is easier to satisfy the stop condition and limit the amount of heat stored in the hot water storage tank 21. Consequently, the hot water storage promotion period begins when the amount of heat stored in the hot water storage tank 21 is small, making it easier to satisfy the start condition and promoting hot water storage during the hot water storage promotion period.

[0061] The control unit 29 normally sets the output of the main heat source unit 10 during hot water storage operation based on the first heat quantity. On the other hand, the output of the main heat source unit 10 during the hot water storage promotion time in consumption priority mode is set based on the second heat quantity. This makes it possible to increase the output of the main heat source unit 10 during the hot water storage promotion time to promote self-consumption of the generated electricity, and the use of commercial electricity for hot water storage is reduced, thereby improving the economic efficiency of hot water storage operation.

[0062] 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]

[0063] 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 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 and supply system comprising 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 control means for controlling the hot water storage operation to drive the heat source unit and the pump to store hot water in the hot water storage tank, The control means predicts the amount of heat required for future hot water supply based on learned and stored hot water supply records as a predicted heat amount for each time period divided into predetermined unit time intervals, and when storing hot water based on the predicted heat amount, it starts the hot water storage operation when the start condition for starting the heat source unit is met, and stops the hot water storage operation when the stop condition for stopping the heat source unit is met. The aforementioned startup condition is met when, while the heat source unit is stopped, the amount of heat in the hot water storage tank is insufficient to reach a first heat amount obtained by summing the predicted heat amounts for a first period from the time period following the time period including the current time to a time period after a predetermined time. The hot water storage and supply system is characterized in that the aforementioned stop condition is met when the amount of heat in the hot water storage tank becomes equal to or greater than the second amount of heat obtained by summing the predicted heat amounts for a second period that is longer than the first period.

2. The aforementioned hot water storage operation allows for hot water storage using electricity generated by an external solar power generation device. The control means has a consumption priority mode that sets the time period during which power generation is expected as a hot water storage promotion time period in order to consume the generated electricity for self-consumption. The hot water supply system according to claim 1, characterized in that, in the consumption priority mode, the first period is set to be longer when the current time is within the hot water storage promotion period than when the current time is outside the hot water storage promotion period.

3. The hot water supply system according to claim 2, characterized in that the control means sets the hot water storage temperature for the hot water storage operation to a predetermined upper limit temperature in the consumption priority mode, and sets the second period to be longer when the current time is within the hot water storage promotion period than when the current time is outside the hot water storage promotion period.

4. The hot water supply system according to claim 3, characterized in that the control means sets a hot water storage restriction period immediately before the hot water storage promotion period in the consumption priority mode, and sets the second period shorter than when the current time is outside the hot water storage promotion period and outside the hot water storage restriction period if the current time is within the hot water storage restriction period.

5. The hot water storage and hot water supply system according to claim 2 or 3, characterized in that the control means normally sets the output of the heat source unit during hot water storage operation based on the first heat quantity, and sets only the output of the heat source unit during hot water storage operation in the hot water storage promotion time period of the consumption priority mode based on the second heat quantity.

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