Hot water storage type hot water supply system and method for using hot water storage type hot water supply system

Abstract

To provide a hot water storage type hot water supply system capable of executing heat storage operation to obtain a high amount of effective heat for cost, even when the electricity price fluctuates minutely depending on the time of day.SOLUTION: In a hot water storage type hot water supply system, it is assumed that virtual heat storage operations of a plurality of patterns are performed, and an additional heat storage amount stored due to the virtual heat storage operation is calculated for each of the virtual thermal storage operations of the plurality of patterns. Of a predicted additional heat storage amount at a predicted time, a portion consumed by a predicted heat load at the predicted time is calculated as an effective additional heat storage amount, and the remaining predicted additional heat storage amount at the predicted time is calculated as a predicted additional heat storage amount for the next predicted time. A cost of one virtual heat storage operation (a cost of generating the effective additional heat storage amount) can be accurately calculated using time-of-day unit costs to calculate a cost effectiveness, enabling heat storage operation with good cost performance.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a storage type hot water supply system and a method for using the storage type hot water supply system. [Background technology]

[0002] A storage-type hot water supply system is known in the art (see, for example, Patent Document 1). The storage-type hot water supply system described in Patent Document 1 includes a heating means, a heat storage tank that stores hot water heated by the heating means, a heat storage operation control means, a fee information acquisition means, and a parameter determination means. The heat storage operation control means controls the heat storage operation to increase the amount of heat stored in the heat storage tank. The fee information acquisition means acquires time-of-day rate setting information, which is information related to the content of time-of-day electricity rate settings, and planned change date information, which is information related to the planned date on which the time-of-day electricity rate settings will be changed. The parameter determination means determines a heat storage operation parameter, which is a control parameter related to the heat storage operation, in accordance with the time-of-day rate setting information.

[0003] Before the scheduled date arrives, the parameter determination means determines the heat storage operation parameters in accordance with first time-zone-specific fee setting information, and after the scheduled date arrives, the parameter determination means determines the heat storage operation parameters in accordance with second time-zone-specific fee setting information different from the first time-zone-specific fee setting information.

[0004] The thermal storage operation includes main thermal storage operation and additional thermal storage operation, which are performed during the time period when the unit price of electricity is lowest. The additional thermal storage operation is started when the amount of thermal storage in the thermal storage tank falls below the minimum amount of thermal storage, and is ended when the amount of thermal storage in the thermal storage tank recovers to a value obtained by adding the additional amount of thermal storage to the minimum amount of thermal storage. The thermal storage operation parameters include the main thermal storage amount, which is the amount of thermal storage stored in the main thermal storage operation, the additional thermal storage amount, and the end time of the main thermal storage operation.

[0005] The parameter determination means sets a lower value for the main heat storage amount after the scheduled date compared to the main heat storage amount before the scheduled date when the maximum unit price / minimum unit price ratio after the scheduled date decreases compared to the maximum unit price / minimum unit price ratio before the scheduled date. Here, the maximum unit price / minimum unit price ratio is the ratio of the electric energy rate unit price for the time period when the electric energy rate unit price is highest to the electric energy rate unit price for the time period when the electric energy rate unit price is lowest. Furthermore, the parameter determination means sets a higher value for the main heat storage amount after the scheduled date compared to the main heat storage amount before the scheduled date when the maximum unit price / minimum unit price ratio after the scheduled date increases compared to the maximum unit price / minimum unit price ratio before the scheduled date.

[0006] Furthermore, the parameter determination means sets a higher value for the additional heat storage amount after the scheduled date compared to the additional heat storage amount before the scheduled date when the highest unit price / lowest unit price ratio after the scheduled date has arrived is smaller than the highest unit price / lowest unit price ratio before the scheduled date has arrived. Furthermore, the parameter determination means sets a lower value for the additional heat storage amount after the scheduled date compared to the additional heat storage amount before the scheduled date when the highest unit price / lowest unit price ratio after the scheduled date has arrived is larger than the highest unit price / lowest unit price ratio before the scheduled date has arrived.

[0007] Furthermore, if the end time of the discount band after the scheduled date arrives is earlier than the end time of the discount band before the scheduled date arrives, the parameter determination means sets the end time of the main thermal storage operation after the scheduled date to be earlier than the end time of the main thermal storage operation before the scheduled date arrives. Here, the discount band end time is the end time of the time period when the unit price of electricity is lowest. Furthermore, if the end time of the discount band after the scheduled date arrives is later than the end time of the discount band before the scheduled date arrives, the parameter determination means sets the end time of the main thermal storage operation after the scheduled date to be later than the end time of the main thermal storage operation before the scheduled date arrives. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-89925 Summary of the Invention [Problem to be solved by the invention]

[0009] The hot water storage type hot water supply system described in Patent Document 1 changes the main heat storage amount and additional heat storage amount according to the maximum unit price / minimum unit price ratio, and changes the main heat storage operation end time according to the end time of the discounted price band. However, when the electricity rate unit price by time of day fluctuates finely, it does not perform detailed control such as operating the heating means by time.

[0010] The present invention has been made in consideration of the above points, and aims to provide a hot water storage type hot water supply system and a method of using a hot water storage type hot water supply system that can perform heat storage operation in which a high amount of effective heat is obtained relative to the cost, even when the electricity price by time of day fluctuates slightly. [Means for solving the problem]

[0011] The hot water storage type hot water supply system of the invention of claim 1 comprises a heating means, a heat storage tank, a control means, an information acquisition means, an effective heat quantity and predicted heat storage quantity calculation means, a predicted heat load calculation means, an additional heat storage quantity calculation means, an effective additional heat quantity and predicted additional heat storage quantity calculation means, a total effective additional heat quantity calculation means, a virtual heat storage operation cost calculation means, an effectiveness-cost calculation means, and a virtual heat storage operation selection means.

[0012] The heat storage tank stores the heat generated by the heating means as hot water.

[0013] The control means can control the heating means to perform a heat storage operation to increase the amount of heat stored in the heat storage tank.

[0014] The information acquisition means acquires information on the amount of heat stored at a certain time, predicted heat demand at each of a plurality of predicted times after the certain time, and the unit price of electricity consumed by the heating means by time period.

[0015] The effective heat quantity and predicted heat storage quantity calculation means sets the heat storage quantity at the given time as the predicted heat storage quantity at the same time as the given time, and calculates the amount of the predicted heat storage quantity at the predicted time that will be consumed by the predicted heat demand at the predicted time as the effective heat quantity from the predicted heat storage quantity and the predicted heat demand at each of multiple predicted times after the given time, and calculates the remaining amount of the predicted heat storage quantity at the predicted time as the predicted heat storage quantity at the next predicted time.

[0016] The predicted heat load calculation means calculates a value obtained by subtracting the available heat quantity at the predicted time from the predicted heat demand at the predicted time, as the predicted heat load at the predicted time.

[0017] The additional heat storage amount calculation means calculates the additional heat storage amount to be stored due to the virtual heat storage operation for each of multiple patterns of virtual heat storage operation with different start times, assuming that the virtual heat storage operation is performed for a predetermined operating period from a start time after the one time.

[0018] The effective additional heat amount and predicted additional heat storage amount calculation means, in each of the multiple patterns of virtual heat storage operation, sets the additional heat storage amount at the start time after the one time as the predicted additional heat storage amount at the same time as the start time, and calculates the effective additional heat amount from the predicted additional heat storage amount and the predicted heat load at each of the multiple predicted times after the one time, that part of the predicted additional heat storage amount at the predicted time that will be consumed by the predicted heat load at the predicted time, and calculates the remaining amount of the predicted additional heat storage amount at the predicted time as the predicted additional heat storage amount at the next predicted time.

[0019] The total effective heat amount calculation means calculates the total effective heat amount by summing up the effective heat amounts at each predicted time in each of the plurality of patterns of the virtual heat storage operation.

[0020] The virtual heat storage operation cost calculation means calculates the virtual heat storage operation cost by summing up the time-zone costs, which are the product of the amount of electricity consumed by the heating means at each predicted time between the start time and the specified operating time and the unit price of electricity for the time zone of the predicted time, for each of the multiple patterns of virtual heat storage operation.

[0021] The cost-effectiveness calculation means calculates cost-effectiveness by dividing the total effective heat amount by the cost of the virtual thermal storage operation for each of the plurality of patterns of the virtual thermal storage operation.

[0022] The virtual thermal storage operation selection means compares the effectiveness versus cost of each of the plurality of patterns of virtual thermal storage operation, and selects the virtual thermal storage operation for which the highest effectiveness versus cost is calculated.

[0023] The control means executes the virtual heat-storage operation selected by the virtual heat-storage operation selection means as the heat-storage operation.

[0024] A storage type hot water supply system according to a second aspect of the present invention is an invention dependent on the first aspect of the present invention, and further comprises a heat storage excess determination means.

[0025] When the sum of the predicted heat storage amount and the predicted additional heat storage amount at any of the predicted times in one of the virtual heat storage operations exceeds a predetermined value that is less than or equal to the maximum heat storage amount of the heat storage tank, the excessive heat storage determination means determines that the virtual heat storage operation is inappropriate and excludes the virtual heat storage operation from the selection targets of the virtual heat storage operation selection means.

[0026] The hot water storage type hot water supply system of the invention of claim 3 is an invention dependent on the invention of claim 1 or 2, and the additional heat storage amount calculation means calculates the additional heat storage amount for each of the multiple patterns of virtual heat storage operation, with the start time being each predicted time up to the predicted time just before the predicted time at which the predicted heat load first becomes positive, at the multiple predicted times having a predetermined time interval.

[0027] The storage-type hot water supply system of the invention of claim 4 is an invention dependent on the invention of any one of claims 1 to 3, and the storage-type hot water supply system further comprises a predicted heat storage amount update means and a predicted heat load update means.

[0028] The predicted heat storage amount updating means sets the virtual heat storage operation most recently selected by the virtual heat storage operation selection means as the previous virtual heat storage operation, and updates the new predicted heat storage amount at each of the plurality of predicted times by adding the predicted additional heat storage amount in the previous virtual heat storage operation to the previous predicted heat storage amount.

[0029] The predicted heat load updating means updates the predicted heat load at each of the plurality of predicted times by subtracting the effective added heat amount in the previous virtual heat storage operation from the immediately preceding predicted heat load.

[0030] The virtual heat storage operation to be selected is additionally selected by the operation of the additional heat storage amount calculation means, the effective additional heat amount and predicted additional heat storage amount calculation means, the total effective additional heat amount calculation means, the virtual heat storage operation cost calculation means, the effectiveness-cost calculation means, and the virtual heat storage operation selection means.

[0031] The hot water storage type hot water supply system according to the invention of claim 5 is an invention dependent on the invention of claim 4, and further comprises means for determining whether or not repeated calculation is necessary.

[0032] The means for determining whether or not repeated calculation is necessary terminates the calculation if the predicted thermal loads at the plurality of predicted times within a predetermined period are all 0, and selects a new virtual thermal storage operation if any of the predicted thermal loads at the plurality of predicted times within a predetermined period are positive.

[0033] A hot water storage type hot water supply system according to claim 6 is an invention dependent on any one of claims 1 to 5, wherein the information acquisition means further acquires information on a predicted surplus amount of power from photovoltaic power generation by time period and a photovoltaic surplus power purchase price by time period. The virtual thermal storage operation cost calculation means calculates the virtual thermal storage operation cost by summing up time period costs consisting of a sum of the product of the amount of power consumed by the heating means at each predicted time period between the start time and the predetermined operation time that can be covered by the predicted surplus amount of power from photovoltaic power generation in the time period of the predicted time and the photovoltaic surplus power purchase price for the time period of the predicted time, and the product of the amount of power consumed by the heating means at each predicted time period between the start time and the predetermined operation time that cannot be covered by the predicted surplus amount of power from photovoltaic power generation in the time period of the predicted time and the electricity unit price for the time period of the predicted time.

[0034] A hot water storage type hot water supply system according to claim 7 is an invention dependent on any one of claims 1 to 6, and includes, in addition to the heating means, a gas heating means for heating by burning gas to meet heat demand. The information acquisition means further acquires information on the boiler efficiency of the gas heating means and the gas unit price, and calculates a gas heating operation cost by multiplying the total effective heat amount of the virtual thermal storage operation selected by the virtual thermal storage operation selection means by the boiler efficiency of the gas heating means and the resulting value by the gas unit price. If the gas heating operation cost is lower than the virtual thermal storage operation cost of the virtual thermal storage operation selected by the virtual thermal storage operation selection means, the virtual thermal storage operation is determined to be inappropriate, and the control means does not execute the virtual thermal storage operation selected by the virtual thermal storage operation selection means as the thermal storage operation.

[0035] The method of using a storage-type hot water supply system according to the invention of claim 8 is a method of using a storage-type hot water supply system according to any one of claims 1 to 5, in which the electricity unit prices for all time periods acquired by the information acquisition means are changed to the same amount.

[0036] The method of using a storage-type hot water supply system according to the invention of claim 9 is a method of using a storage-type hot water supply system according to any one of claims 1 to 5, wherein the information acquisition means additionally acquires information on time periods when commercial power is scarce, and the electricity unit price for the time periods when commercial power is scarce acquired by the information acquisition means is changed to an amount higher than the highest electricity unit price for the time periods.

[0037] The method of using a storage-type hot water supply system according to the invention of claim 10 is a method of using a storage-type hot water supply system according to any one of claims 1 to 5, wherein the information acquisition means additionally acquires information on time periods when there is surplus commercial electricity, and for the electricity unit price for each time period acquired by the information acquisition means, the electricity unit price for the time period when there is surplus commercial electricity is changed to an amount lower than the lowest electricity unit price for that time period. [Effects of the Invention]

[0038] In the hot water storage type hot water supply system according to the invention of claim 1, the additional heat storage amount calculation means assumes that multiple patterns of virtual heat storage operation are performed, and calculates the additional heat storage amount to be stored due to the virtual heat storage operation for each of the multiple patterns of virtual heat storage operation.

[0039] The effective additional heat amount and predicted additional heat storage amount calculation means, for each of the multiple patterns of virtual thermal storage operation, determines the predicted thermal load at the predicted time as the effective additional heat amount if the predicted additional thermal storage amount is greater than the predicted thermal load at that predicted time. That is, the predicted thermal load occurs when the thermal storage amount is zero. However, assuming that virtual thermal storage operation is performed, it can be assumed that the amount of thermal storage that would have been zero without virtual thermal storage operation is generated by the predicted additional thermal storage amount. In this case, if the predicted additional thermal storage amount at the predicted time is greater than the predicted thermal load, the virtual thermal storage operation has already covered the entire predicted thermal load that would have been required without virtual thermal storage operation, and this is determined as the effective additional heat amount. Furthermore, if the predicted additional thermal storage amount at the predicted time is smaller than the predicted thermal load, only a portion (the amount corresponding to the predicted additional thermal storage amount) of the predicted thermal load that would have been required without virtual thermal storage operation has already been covered by virtual thermal storage operation. In this case, only the amount corresponding to the predicted additional thermal storage amount is determined as the effective additional heat amount. In this way, the effective heat amount for each predicted time can be summed up to calculate the total effective heat amount generated in one entire virtual heat storage operation.

[0040] Then, a hypothetical thermal storage operation cost can be accurately calculated using the time-of-day unit price, and the cost-effectiveness can be calculated using the cost-effectiveness calculation means, making it possible to carry out thermal storage operation with good cost performance.

[0041] In the hot water storage type hot water supply system according to the invention of claim 2, an infeasible virtual heat storage operation in which the amount of heat stored in the heat storage tank exceeds the maximum amount of heat storage is excluded from the selection options, thereby preventing the selection of an inappropriate virtual heat storage operation.

[0042] The hot water storage type hot water supply system of the invention of claim 3 limits the start times of multiple patterns of virtual heat storage operation to each predicted time, among multiple predicted times having a predetermined time interval, up to the predicted time just before the predicted time at which the predicted heat load first becomes positive, thereby limiting the number of patterns of virtual heat storage operation and reducing the amount of calculation required.

[0043] The hot water storage type hot water supply system of the invention of claim 4 selects a new virtual heat storage operation based on one selected virtual heat storage operation, so that two virtual heat storage operations can be selected with minimal calculation by effectively utilizing the previously selected virtual heat storage operation.

[0044] The hot water storage type hot water supply system of the invention of claim 5 selects a new virtual heat storage operation based on multiple previously selected virtual heat storage operations, so that multiple virtual heat storage operations can be selected with minimal calculation by effectively utilizing the multiple previously selected virtual heat storage operations.

[0045] The hot water storage type hot water supply system of the invention of claim 6 can accurately calculate the cost-benefit ratio of virtual heat storage operation even when using electricity generated by a solar power generation system in addition to commercial electricity, and can perform heat storage operation with good cost performance.

[0046] The hot water storage type hot water supply system of the invention of claim 7, even when equipped with a gas heating means that heats by burning gas in addition to a heating means that operates on electricity, can accurately compare the cost-effectiveness of the two heating means, and when inappropriate heat storage operation is not performed and the heat storage amount is insufficient, the heat demand is automatically met by the gas heating means, so the heat demand can be met with high cost performance.

[0047] In the method of using the hot water storage type hot water supply system of the invention of claim 8, the cost-effectiveness ratio for each virtual heat storage operation is the effective heating amount that reflects the effects of heat loss due to heat radiation and start-up / shutdown losses, and by selecting a virtual heat storage operation with a high cost-effectiveness ratio, it is possible to easily select an energy-saving operation with small heat loss due to heat radiation and start-up / shutdown losses.

[0048] In the method of using the hot water storage type hot water supply system according to the invention of claim 9, it becomes easy to avoid the heat storage operation during times when commercial power is tight.

[0049] In the method of using the hot water storage type hot water supply system according to the invention of claim 10, it becomes easier to easily induce the heat storage operation to occur during times when there is a surplus of commercial electricity. [Brief explanation of the drawings]

[0050] [Figure 1] FIG. 1 is a schematic diagram of a storage-type hot water supply system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of a processing unit according to the first embodiment. [Figure 3] FIG. 3 is a flow diagram of calculations for highly efficient heat storage operation according to the first embodiment. [Figure 4] FIG. 4 is a block diagram of a processing unit according to the second embodiment. [Figure 5] FIG. 5 is a flow chart of calculations for highly efficient heat storage operation according to the second embodiment. [Figure 6] FIG. 6 is a schematic configuration diagram of a storage-type hot water supply system according to the third embodiment. [Figure 7] FIG. 7 is a schematic configuration diagram of a storage-type hot water supply system according to the fourth embodiment. [Figure 8] FIG. 8 is a block diagram of a processing unit according to the fourth embodiment. [Figure 9] FIG. 9 is a flow chart of calculations for highly efficient heat storage operation according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0051] A storage type hot water supply system according to the present invention will be described below with reference to the drawings. First, the basic configuration of a typical storage type hot water supply system will be described with reference to FIG.

[0052] (1) Basic configuration of a storage-type hot water supply system The storage type hot water supply system 1 basically comprises a heating means 2, a main heat medium circuit 31 through which a main heat medium flows that recovers heat generated by the heating means 2, a heat storage tank 3, and a control means 4. A heat recovery heat exchanger 32 is connected midway through the main heat medium circuit 31. The heat generated by the heating means 2 is recovered by the main heat medium flowing through the main heat medium circuit 31 via the heat recovery heat exchanger 32.

[0053] In this embodiment, the heating means 2 is a heat pump type heating device driven by electricity, but is not limited to a heat pump type and may be a heating device driven by electricity, such as an electric heating wire, and is not particularly limited.

[0054] The heating means 2 operates using power (commercial power) from a commercial power source 90. In Fig. 1, reference numeral 91 denotes a power meter, reference numeral 92 denotes a distribution board, and reference numeral 100 denotes power loads other than the heating means 2, such as air conditioning equipment and lighting devices used in homes, etc.

[0055] The heating means 2 is controlled by the control means 4. The control means 4 has a computer including a processor such as a CPU (Central Processing Unit) and a memory, and performs various controls by executing appropriate programs. The control means 4 controls the activation / deactivation and heat generation amount of the heating means 2 to perform heat utilization operation. The control means 4 starts the heat utilization operation in response to a start operation of the heat utilization operation on the operation unit 41, and stops the heat utilization operation in response to a stop operation of the heat utilization operation.

[0056] The control means 4 also includes a communication interface that complies with a predetermined communication protocol, and is configured to be able to communicate with a server 8 via a network 7 such as the Internet.

[0057] Furthermore, the control means 4 can control the heating means 2 to execute a heat storage operation that increases the amount of heat stored in the heat storage tank 3. Furthermore, the control means 4 executes a selected virtual heat storage operation, which will be described later, as the heat storage operation.

[0058] A heat storage tank (hot water storage tank) 3 is provided in the main heat medium circuit 31. The heat storage tank 3 stores the heat generated by the heating means 2 as hot water. A hot water outlet pipe 33 is connected to the heat storage tank 3, and a hot water supply pipe 331 for hot water supply and a hot water filling pipe 332 for filling the bath are branched off midway through this hot water outlet pipe 33. This allows the hot water from the heat storage tank 3 to be mixed with water as appropriate, and temperature-adjusted hot water can be discharged through the hot water supply pipe 331 and the hot water filling pipe 332. The heat storage tank 3 is equipped with various sensors, which can acquire data such as the amount of hot water stored in the heat storage tank 3, the water temperature, and the water temperature distribution.

[0059] Furthermore, a parallel flow path 35 connected to a heat exchanger 34 is provided in the main heat medium circuit 31 in parallel with the heat storage tank 3. The primary flow path of the heat exchanger 34 is connected to the parallel flow path 35, and the secondary flow path is connected to a reheating circulation circuit 36. Bath water drawn into the reheating circulation circuit 36 ​​from the bathtub 37 is heated by the heat exchanger 34 and can then be discharged back into the bathtub 37.

[0060] The hot water storage type hot water supply system 1 includes a bathtub device. The bathtub device has a bathtub filling function, a reheating function, and an automatic bath function. The bathtub device is composed of a bathtub 37, a bathtub filling pipe 332, and a reheating circulation circuit 36. The bathtub filling function discharges hot water into the bathtub 37 through the bathtub filling pipe 332, filling the bathtub 37 to a predetermined level (a predetermined amount). The water level in the bathtub 37 can be detected by a water level sensor located in the bathtub 37, the bathtub filling pipe 332, or the reheating circulation circuit 36. The reheating function draws hot water from the bathtub 37 via the reheating circulation circuit 36, heats it with the main heat medium, and generates hot water at a higher temperature, which is then discharged into the bathtub 37. The automatic bath function combines a function to discharge hot water into the bathtub 37 until the water level in the bathtub 37 drops below the predetermined level, and a function to maintain the temperature of the water in the bathtub 37 at a predetermined temperature using the reheating function.

[0061] (2) First embodiment The hot water storage type hot water supply system 1 includes a processing unit 50 that performs calculations for highly efficient heat storage operation. The processing unit 50 is provided in the control means 4 and constitutes a part of the control means 4. The calculations for highly efficient heat storage operation by the processing unit 50 are executed as one of the various functions of the control means 4.

[0062] 2, the processing unit 50 has an information acquisition means 51, an effective heat amount and predicted heat storage amount calculation means 52, a predicted heat load calculation means 53, an additional heat storage amount calculation means 54, an effective additional heat amount and predicted additional heat storage amount calculation means 55, an excess heat storage determination means 56, a total effective additional heat amount calculation means 57, a virtual heat storage operation cost calculation means 58, a cost-effectiveness calculation means 59, and a virtual heat storage operation selection means 60. Each function of the information acquisition means 51 to the virtual heat storage operation selection means 60 constitutes one function of the processing unit 50 (control means 4).

[0063] The following describes the calculations for highly efficient heat storage operation executed by the processing unit 50. Fig. 3 shows a flow chart of calculations for highly efficient heat storage operation in the hot water storage type hot water supply system 1.

[0064] (2.1) Information acquisition After calculation for highly efficient heat storage operation is started, the information acquisition means 51 executes an information acquisition flow in (S1). In the information acquisition flow, information on the amount of stored heat at a certain time, predicted heat demand at each of a plurality of predicted times after the certain time, and the unit price of electricity consumed by the heating means 2 by time period is acquired.

[0065] The amount of heat stored at a given time is, for example, the amount of heat stored (in units of, for example, MJ) in the heat storage tank 3 at a given point in time, such as the present (current time) or Reiwa year, month, day, hour, minute, and second. The amount of heat stored can be calculated from the amount and temperature of hot water stored in the heat storage tank 3. Data on the amount of heat stored is acquired from the heat storage tank 3 by the information acquisition means 51.

[0066] For example, if the aforementioned time is 00:00:00 on January 1, 2024, the multiple predicted times after that will be every hour on the hour, such as 1:00:00 on January 1, 2024, 2:00:00 on January 1, 2024, etc.

[0067] Note that the multiple predicted times after the one time may or may not include the one time as a predicted time. In the first embodiment, the multiple predicted times after the one time include the one time. Furthermore, the time intervals between the multiple predicted times do not have to be one-hour intervals, but may be any predetermined time interval, such as 30-minute intervals or two-hour intervals. Furthermore, the time intervals between the multiple predicted times do not have to be equal intervals. Furthermore, the number of multiple predicted times is not limited.

[0068] In the detailed explanation below, when simply referring to ○ hours ○ minutes ○ seconds, this is an abbreviation for "January 1, 2024."

[0069] The predicted heat demand is the heat demand predicted to be required in this hot water storage type hot water supply system 1 within a predetermined time range that includes one of multiple predicted times after the one time. For example, as described above, if the one time is 0:00:00 and the multiple predicted times are 1:00:00, 2:00:00, etc., the predicted heat demand at the one time is after 0:00:00 and before 1:00:00 (but excluding 1:00:00), and the predicted heat demand at the predicted time 1:00:00 is after 1:00:00 and before 2:00:00 (but excluding 2:00:00), etc. Note that when specifying the time range of the predicted heat demand, the predicted time may be set in the middle of the predetermined time range.

[0070] The predicted heat demand at multiple predicted times is acquired by the information acquisition means 51 from the server 8 via the network 7. The server 8 is a management server for the hot water storage type hot water supply system 1, and acquires data on the operation and status of the hot water storage type hot water supply system 1 via the network 7.

[0071] The predicted heat demands at the plurality of predicted times may be generated by the control means 4 (excluding the processing unit 50), and the source of the predicted heat demands is not limited.

[0072] A time-zone-specific unit price is set for the electricity unit price of the amount of electricity consumed by the heating means 2, with the unit price varying for each time zone. For example, the electricity unit price is set at 16 yen / kWh for the time zone including the time 0:00:00 (after 0:00:00 and before 1:00:00, excluding 1:00:00), and 18 yen / kWh for the time zone including 1:00:00 (after 1:00:00 and before 2:00:00, excluding 2:00:00).

[0073] The information on the electricity unit price by time period is acquired by the information acquisition means 51 from the server 8 via the network 7. The server from which the information is acquired may not be the server 8 of the hot water storage type hot water supply system 1 but may be another general server, and is not particularly limited.

[0074] (2.2) Calculation of available heat and predicted heat storage In (S2), the effective heat quantity and predicted heat storage quantity calculation means 52 executes a flow for calculating the effective heat quantity and predicted heat storage quantity. In the flow for calculating the effective heat quantity and predicted heat storage quantity, the heat storage quantity at a certain time is set as the predicted heat storage quantity at the same time as the certain time, and from the predicted heat storage quantity and predicted heat demand at each of a plurality of predicted times after the certain time, the part of the predicted heat storage quantity at the predicted time that will be consumed by the predicted heat demand at the predicted time is calculated as the effective heat quantity, and the remaining amount of the predicted heat storage quantity at the predicted time is calculated as the predicted heat storage quantity at the next predicted time.

[0075] If the predicted heat storage amount at a predicted time is greater than the predicted heat demand at that time, the effective heat amount is equal to the predicted heat demand, and if it is less than the predicted heat storage amount, the effective heat amount is equal to the predicted heat demand. Therefore, the effective heat amount at any predicted time is never greater than the predicted heat demand at the same time.

[0076] For example, if the predicted heat storage amount at the predicted time of 00:00:00 is 2 MJ and the predicted heat demand at the same time is 0 MJ, the effective heat amount, which is the predicted heat demand covered by the predicted heat storage amount, is 0 MJ, and the predicted heat storage amount at the next predicted time of 1:00:00 is 2 MJ. Note that in reality, there is a decrease in the heat storage amount due to heat dissipation, so it is preferable to also take into account the decrease in the heat storage amount due to heat dissipation, as this is closer to reality. If the heat dissipation rate over one hour is 5% and the decrease in the heat storage amount due to heat dissipation is taken into account, the predicted heat storage amount at 1:00:00 in the above case will be 1.9 MJ.

[0077] For example, if the predicted heat storage amount at the predicted time of 00:00:00 is 2 (MJ) and the predicted heat demand at the same time is 1 (MJ), the effective heat amount, which is the predicted heat demand covered by the predicted heat storage amount, is 1 (MJ), and the predicted heat storage amount at the next predicted time of 1:00:00 is (heat storage amount 2 - effective heat amount 1) x (1 - 0.05) = 0.95 (MJ).

[0078] Furthermore, for example, if the predicted heat storage amount at the predicted time of 00:00:00 is 2 (MJ) and the predicted heat demand at the same time is 3 (MJ), the effective heat amount, which is the predicted heat demand covered by the predicted heat storage amount, is 2 (MJ), and the predicted heat storage amount at the next predicted time of 1:00:00 is (heat storage amount 2 - effective heat amount 2) x (1 - 0.05) = 0 (MJ).

[0079] The calculation of the effective heat quantity and the predicted heat storage quantity is repeated by delaying the predicted time until the predicted heat storage quantity becomes 0, and the predicted heat storage quantity at each predicted time after the predicted time when the predicted heat storage quantity becomes 0 for the first time will basically be 0.

[0080] (2.3) Predicted heat load calculation In (S3), the predicted heat load calculation means 53 executes a predicted heat load calculation flow. In the predicted heat load calculation flow, the value obtained by subtracting the available heat quantity at the predicted time from the predicted heat demand at the predicted time is set as the predicted heat load at this predicted time.

[0081] For example, if the predicted heat demand at the predicted time of 0:00:00 is 1 (MJ) and the available heat quantity at the same time is 1 (MJ), the predicted heat load at the same time is 0 (MJ).

[0082] Furthermore, for example, if the predicted heat demand at the predicted time of 0:00:00 is 3 (MJ) and the available heat quantity at the same time is 2 (MJ), the predicted heat load at the same time is 1 (MJ).

[0083] (2.4) Calculation of additional heat storage In (S4), the additional heat storage amount calculation means 54 executes an additional heat storage amount calculation flow. In the additional heat storage amount calculation flow, assuming that a virtual heat storage operation is performed for a predetermined operation time from a start time after a certain time as the heat storage operation, the additional heat storage amount stored due to this virtual heat storage operation is calculated for each of a plurality of patterns of virtual heat storage operation with different start times.

[0084] The virtual heat storage operation starts, for example, at 0:00:00, and operates for one hour as a predetermined operation time. If the increase in the heat quantity in the heat storage tank 3 when the heating means 2 operates for one hour is 7.2 (MJ), the increase in the heat storage quantity due to the virtual heat storage operation is also 7.2 (MJ). Therefore, the additional heat storage quantity at the next predicted time, 1:00:00, will be 7.2 (MJ). Furthermore, since the virtual heat storage operation is not performed at the next predicted time, 1:00:00 (including the time period), the additional heat storage quantity will not increase, but unless the additional heat storage quantity at 1:00:00 decreases, the additional heat storage quantity at the next predicted time, 2:00:00, will remain at 7.2 (MJ).

[0085] The specified operating time does not have to be one hour, but may be, for example, 30 minutes, or may span two hours, three hours, etc., multiple predicted times (including time periods) or multiple time periods with different time-based unit prices.

[0086] It is also preferable to consider heat dissipation when considering the additional heat storage amount. If the heat dissipation rate is 5%, the additional heat storage amount at 2:00:00 is 6.84 (MJ).

[0087] Furthermore, since there is actually energy loss (start-stop loss) due to the start-up and stop of the heating means 2 when the virtual heat storage operation is started and stopped, it is preferable to also consider the decrease in the amount of additional heat storage due to the start-stop loss, as this is closer to reality. For example, if there is no start-stop loss or loss due to heat dissipation, the additional heat storage amount at 1:00:00 is assumed to be 7.2 (MJ) due to the virtual heat storage operation. In this case, if the start-stop loss is taken into account and the start-stop loss is set to 0.72 (MJ), the additional heat storage amount at 1:00:00 is 6.48 (MJ). Furthermore, if heat dissipation is taken into account (heat dissipation rate 5%), the additional heat storage amount at 1:00:00 is 6.156 (MJ).

[0088] In the additional heat storage amount calculation flow, the additional heat storage amount is calculated for a plurality of patterns of virtual heat storage operation. For example, the additional heat storage amount is calculated for each of a plurality of predicted times for a plurality of patterns of virtual heat storage operation, such as a virtual heat storage operation starting at 0:00:00, which is one time, a virtual heat storage operation starting at 1:00:00, which is the next predicted time, etc. In the additional heat storage amount calculation flow, the number of patterns of virtual heat storage operation for which the additional heat storage amount is calculated is not particularly limited.

[0089] Since the heating means 2 cannot instantly cover the heat demand, it is preferable that the start time of the virtual heat storage operation be up to the predicted time immediately before the predicted time when the predicted heat load first becomes positive.

[0090] (2.5) Calculation of effective heat capacity and predicted additional heat storage capacity In (S5), the effective additional heat amount and predicted additional heat storage amount calculation means 55 executes a flow for calculating the effective additional heat amount and predicted additional heat storage amount. In the flow for calculating the effective additional heat amount and predicted additional heat storage amount, for each of a plurality of patterns of virtual heat storage operation, the additional heat storage amount at the start time after one time is set as the predicted additional heat storage amount at the same time as the start time, and from the predicted additional heat storage amount and predicted heat load at each of a plurality of predicted times after one time, the part of the predicted additional heat storage amount at the predicted time that is consumed by the predicted heat load at the predicted time is calculated as the effective additional heat amount, and the remaining amount of the predicted additional heat storage amount at the predicted time is calculated as the predicted additional heat storage amount at the next predicted time.

[0091] That is, in a certain pattern of virtual thermal storage operation, if the predicted additional thermal storage amount at the predicted time is greater than the predicted thermal load at the predicted time, the entire predicted thermal load at this predicted time (including the time period) can be covered by the predicted additional thermal storage amount. In other words, for the predicted thermal load that occurred at this predicted time, if thermal storage operation had not been performed, the predicted thermal load that could not have been covered by the heating means 2 can be covered by the thermal storage amount (predicted additional thermal storage amount) in the thermal storage tank 3 by performing thermal storage operation of this pattern in advance. From this perspective, the entire predicted thermal load is treated as an effective additional heating amount that can be effectively substituted.

[0092] For example, if the predicted additional heat storage amount at the predicted time of 1:00:00 is 3 (MJ) and the predicted heat load is 2 (MJ), the effective additional heat amount is 2 (MJ).

[0093] Furthermore, if the predicted additional heat storage capacity at the predicted time is smaller than the predicted heat load at this predicted time, the predicted additional heat storage capacity cannot cover the entire predicted heat load at this predicted time (including the time period). Therefore, only the predicted additional heat storage capacity at this predicted time is used as the effective additional heat capacity at this predicted time.

[0094] For example, if the predicted additional heat storage amount at the predicted time of 1:00:00 is 2 (MJ) and the predicted heat load is 3 (MJ), the effective additional heat amount is 2 (MJ).

[0095] In the virtual heat storage operation of each pattern, the calculation of the effective additional heat storage amount is performed for each predicted time up to the predicted time when the predicted additional heat storage amount becomes 0 for the first time.

[0096] (2.6) Excessive heat storage determination In (S6), the excess heat storage determination means 56 executes an excess heat storage determination flow. In the excess heat storage determination flow, if the sum of the predicted heat storage amount and the predicted additional heat storage amount at any predicted time in one virtual heat storage operation exceeds a predetermined value that is equal to or less than the maximum heat storage amount in the heat storage tank 3, the virtual heat storage operation is determined to be inappropriate, and the virtual heat storage operation is excluded from the selection targets of the virtual heat storage operation selection means 60.

[0097] In the flow for calculating the effective heat amount and the predicted additional heat storage amount, the predicted additional heat storage amount at each predicted time when each pattern of virtual heat storage operation is performed is calculated, and in the flow for determining excess heat storage, it is determined whether or not all of this predicted additional heat storage amount can be effectively stored in the heat storage tank 3.

[0098] The heat storage excess determining means 56 is an optional configuration and does not have to be provided in the processing unit 50 (control means 4).

[0099] There is a maximum heat storage capacity (full heat storage capacity) in the heat storage tank 3. The predicted heat storage capacity at each predicted time is the heat storage capacity when virtual heat storage operation is not performed, and when virtual heat storage operation is performed, the value of the heat storage capacity of the heat storage tank 3 at the predicted time is the value obtained by adding the predicted additional heat storage capacity to the predicted heat storage capacity at this predicted time.

[0100] If the value obtained by adding the predicted additional heat storage amount to the predicted heat storage amount exceeds the maximum heat storage amount of the heat storage tank 3 (excessive heat storage state), the amount exceeding the maximum heat storage amount will not be stored, and therefore not all of the predicted additional heat storage amount will be effectively stored. From this perspective, if an excessive heat storage state occurs at any predicted time in the virtual heat storage operation of each pattern, the virtual heat storage operation of this pattern is excluded as inappropriate. In the excessive heat storage determination flow, an inappropriate flag is set for the virtual heat storage operation in which an excessive heat storage state occurs.

[0101] The threshold value for determining whether or not the state of excessive heat storage is present is basically the maximum amount of heat storage in the heat storage tank 3. However, even if the value obtained by adding the predicted additional amount of heat storage to the predicted amount of heat storage does not exceed the maximum amount of heat storage in the heat storage tank 3, the actual amount of heat storage at the predicted time may exceed the predicted amount of heat storage. Therefore, the threshold value may be a predetermined value equal to or less than the maximum amount of heat storage.

[0102] (2.7) Calculation of total effective heat In (S7), the total effective heat amount calculation means 57 executes a total effective heat amount calculation flow. In the total effective heat amount calculation flow, the effective heat amount at each predicted time is summed up for each of the multiple patterns of virtual thermal storage operation to calculate the total effective heat amount.

[0103] In the virtual heat storage operation of each pattern, the total effective additional heat amount is calculated for each predicted time up to the predicted time when the predicted additional heat storage amount becomes 0 for the first time.

[0104] For example, let us assume that 0:00:00 is the start time of one pattern of virtual thermal storage operation, the predicted times are 1:00:00, 2:00:00, and 3:00:00, and that the predicted additional thermal storage amount first reaches 0 at 3:00:00. In this case, if the effective additional heating amount at 0:00:00 is 0 (MJ), the effective additional heating amount at 1:00:00 is 0 (MJ), the effective additional heating amount at 2:00:00 is 3.5 (MJ), and the effective additional heating amount at 3:00:00 is 3 (MJ), then the total effective additional heating amount is 6.5 (MJ).

[0105] It should be noted that for the virtual heat storage operation for which an inappropriate flag is set in the heat storage excess determination flow, the total effective heat amount does not need to be calculated.

[0106] (2.8) Calculation of virtual thermal storage operating costs In (S8), the virtual thermal storage operation cost calculation means 58 executes a virtual thermal storage operation cost calculation flow. In the virtual thermal storage operation cost calculation flow, for each of a plurality of patterns of virtual thermal storage operation, the virtual thermal storage operation cost is calculated by summing up the costs by time slot, which are the product of the amount of power consumed by the heating means 2 and the unit price of power in the time slot of this predicted time, at each predicted time from the start time to a predetermined operation time.

[0107] For example, for one pattern of virtual thermal storage operation, if the operation starts at 00:00:00 and runs for one hour, consuming 1 kWh of electricity, and the unit price of electricity for the time slot at 00:00:00 is 20 yen / kWh, the time slot cost for the time slot at 00:00:00 will be 20 yen. Also, since the operating time of the virtual thermal storage operation is only one hour, the virtual thermal storage operation cost will be 20 yen.

[0108] It should be noted that for a virtual thermal storage operation for which an inappropriate flag has been set in the flow for determining whether or not the thermal storage is excessive, the virtual thermal storage operation cost does not need to be calculated.

[0109] (2.9) Benefit-cost calculation In (S9), the cost-effectiveness calculation means 59 executes a cost-effectiveness calculation flow. In the cost-effectiveness calculation flow, the cost-effectiveness is calculated by dividing the total effective heat amount by the cost of the virtual thermal storage operation for each of the multiple patterns of virtual thermal storage operation.

[0110] For example, if the total effective heat amount for one pattern of virtual thermal storage operation is 3 (MJ) and the virtual thermal storage operation cost is 20 (yen), the cost-effectiveness ratio for this pattern of virtual thermal storage operation is 0.15. Note that, since the cost-effectiveness ratio is only compared between each virtual thermal storage operation, the unit of cost-effectiveness ratio is not particularly limited as long as it is the same for the cost-effectiveness ratio of all virtual thermal storage operations.

[0111] It should be noted that the cost-benefit calculation does not need to be performed for the virtual thermal storage operation for which an inappropriate flag has been set in the thermal storage excess determination flow.

[0112] (2.10) Virtual heat storage operation selection In (S10), the virtual heat storage operation selection means 60 executes a virtual heat storage operation selection flow. In the virtual heat storage operation selection flow, the effectiveness versus cost of each of a plurality of patterns of virtual heat storage operation is compared, and the virtual heat storage operation with the highest calculated effectiveness versus cost is selected.

[0113] In the cost-effectiveness calculation flow, the virtual thermal storage operation for which the inappropriate flag is set in the excessive thermal storage determination flow is not selected. In the virtual thermal storage operation selection flow, the cost-effectiveness of the virtual thermal storage operations that are not not selected is compared, and the virtual thermal storage operation with the highest calculated cost-effectiveness is selected.

[0114] After the virtual heat-storage operation selection flow is completed, the control means 4 (processing unit 50) finishes the calculation for the highly efficient heat-storage operation, and then the control means 4 executes the highly efficient heat-storage operation.

[0115] (2.11) Summary of the first embodiment The hot water storage type hot water supply system 1 calculates the effective additional heat amount and the predicted additional heat storage amount at each predicted time, and the total effective additional heat amount, for a plurality of patterns of virtual heat storage operation.

[0116] Furthermore, by using the total effective heat amount and the time-zone unit price, the cost-benefit ratio for the hypothetical thermal storage operation can be calculated more accurately, and thermal storage operation with good cost performance can be performed.

[0117] Furthermore, by executing the excessive heat storage determination flow, an inappropriate virtual heat storage operation in which the amount of stored heat exceeds the maximum amount of stored heat is excluded from the selection targets, thereby preventing a decrease in the cost performance of the heat storage operation.

[0118] (3) Second embodiment Calculations for the highly efficient thermal storage operation of the second embodiment will be described with reference to Fig. 4 and Fig. 5. As shown in Fig. 4, the processing unit 50 includes an information acquisition means 51, an available heat amount and predicted thermal storage amount calculation means 52, a predicted thermal load calculation means 53, an additional thermal storage amount calculation means 54, an available additional heat amount and predicted additional thermal storage amount calculation means 55, an excess thermal storage determination means 56, a total available additional heat amount calculation means 57, a virtual thermal storage operation cost calculation means 58, a cost-effectiveness calculation means 59, and a virtual thermal storage operation selection means 60, as well as a predicted thermal storage amount update means 61, a predicted thermal load update means 62, and a means 63 for determining whether or not repeated calculation is necessary.

[0119] The calculation process from the start of calculations for high-efficiency thermal storage operation to the virtual thermal storage operation selection flow allows the most cost-effective thermal storage operation to be determined for the first time. However, if the additional thermal storage capacity of the first virtual thermal storage operation is less than the predicted thermal load at the predicted time when the predicted thermal load first becomes positive, it will not be able to cover the entire predicted thermal load. Therefore, the predicted additional thermal storage capacity when this virtual thermal storage operation is performed is added to the predicted thermal storage capacity when thermal storage operation is not performed, and one of the predicted times up to the predicted time just before the predicted time when the predicted thermal load first becomes positive is selected as the start time for the second virtual thermal storage operation. By repeating this process for the third virtual thermal storage operation, the fourth virtual thermal storage operation, and so on, it is possible to reduce the predicted thermal load at multiple predicted times within a specified period to zero.

[0120] As shown in FIG. 5, the calculation flow for the highly efficient heat storage operation of the second embodiment is the same as the calculation flow for the highly efficient heat storage operation of the first embodiment from the start of calculation to (S10), and therefore the explanation will be omitted.

[0121] (3.1) Update of predicted heat storage In (S11), the predicted heat storage amount updating means 61 executes a predicted heat storage amount updating flow. In the predicted heat storage amount updating flow, the virtual heat storage operation selected immediately before by the virtual heat storage operation selecting means 60 is set as the previous virtual heat storage operation.

[0122] Next, in the predicted heat storage amount update flow, at each of the plurality of predicted times, the predicted heat storage amount is updated to a new value obtained by adding the predicted additional heat storage amount in the previous virtual heat storage operation to the immediately preceding predicted heat storage amount.

[0123] When selecting the second virtual heat storage operation, the predicted additional heat storage amount in the first virtual heat storage operation is added to the predicted heat storage amount calculated by the effective heat amount and predicted heat storage amount calculation means 52 at each of the multiple predicted times, and updated as a new predicted heat storage amount.

[0124] When selecting the third virtual heat storage operation, the predicted additional heat storage amount in the second virtual heat storage operation is added to the predicted additional heat storage amount in the first virtual heat storage operation at each of the multiple predicted times to update the new predicted heat storage amount. When selecting the fourth or subsequent virtual heat storage operation, the predicted heat storage amount is updated in the same manner.

[0125] (3.2) Predicted heat load update In step S12, the predicted heat load update means 62 executes a predicted heat load update flow. In the predicted heat load update flow, at each of a plurality of predicted times, the predicted heat load is updated by subtracting the effective heating amount in the previous virtual heat storage operation from the immediately preceding predicted heat load.

[0126] When selecting the second virtual heat storage operation, the effective heating amount in the first virtual heat storage operation is subtracted from the predicted heat load calculated by the predicted heat load calculation means 53 at each of the multiple predicted times, and the result is updated as a new predicted heat load.

[0127] When selecting the third virtual thermal storage operation, the new predicted thermal load is updated by subtracting the effective added heating amount in the second virtual thermal storage operation from the predicted thermal load updated by subtracting the effective added heating amount in the first virtual thermal storage operation at each of the multiple predicted times. When selecting the fourth or subsequent virtual thermal storage operation, the predicted thermal load is updated in the same manner.

[0128] (3.3) Deciding whether or not to repeat calculations In (S13), the repeat calculation necessity determination means 63 executes a repeat calculation necessity determination flow. In the repeat calculation necessity determination flow, it is determined whether or not another calculation of the virtual thermal storage operation is necessary. If the predicted thermal loads at a plurality of predicted times within a predetermined period are all 0, it is determined that another calculation of the virtual thermal storage operation is unnecessary, and the calculation is terminated. If any of the predicted thermal loads at a plurality of predicted times within a predetermined period are positive, it is determined that another calculation of the virtual thermal storage operation is necessary, and (S4) to (S10) are executed again to select a new virtual thermal storage operation. Next, (S11) to (S12) are executed to update the predicted thermal storage amount and predicted thermal load.

[0129] (3.4) Summary of the second embodiment In the second embodiment, if there are any positive predicted heat loads at multiple predicted times within a specified period, it is determined that the virtual heat storage operation needs to be calculated again, a new virtual heat storage operation is selected, and the predicted heat storage amount and predicted heat load are updated. Therefore, by effectively utilizing the multiple virtual heat storage operations previously selected, the predicted heat loads at multiple predicted times within a specified period can be reliably set to 0 with minimal calculations.

[0130] (4) Third embodiment A storage-type hot water supply system 1 according to a third embodiment will be described with reference to FIG. 6. The storage-type hot water supply system 1 according to the third embodiment is largely the same as the storage-type hot water supply systems 1 according to the first and second embodiments shown in FIG. 1. Therefore, the same components are denoted by the same reference numerals and will not be described again. The block diagram of the processing unit according to the third embodiment is the same as the block diagram of the processing unit according to the first embodiment shown in FIG. 2 or the block diagram of the processing unit according to the second embodiment shown in FIG. 4. Therefore, FIGS. 2 and 4 are used as the block diagram of the processing unit according to the third embodiment. The calculation flow diagram for the highly efficient heat storage operation according to the third embodiment is the same as the calculation flow diagram for the highly efficient heat storage operation according to the first embodiment shown in FIG. 3 or the calculation flow diagram for the highly efficient heat storage operation according to the second embodiment shown in FIG. 5. Therefore, FIGS. 3 and 5 are used as the calculation flow diagram for the highly efficient heat storage operation according to the third embodiment. Below, differences from the storage-type hot water supply systems 1 according to the first and second embodiments will be mainly described.

[0131] (4-1) Solar power generation system As shown in Fig. 6, the hot water storage type hot water supply system 1 of the third embodiment differs from the hot water storage type hot water supply systems 1 of the first and second embodiments in that it operates in conjunction with a solar power generation system. Specifically, the hot water storage type hot water supply system 1 can use power generated by the solar power generation system in addition to a commercial power source 90. In Fig. 6, reference numeral 93 denotes a solar power generation panel provided in the solar power generation system, and reference numeral 94 denotes a power conditioner.

[0132] (4-2) Information acquisition means, virtual thermal storage operating cost calculation means Furthermore, the third embodiment of the hot water storage type hot water supply system 1 differs from the first and second embodiments of the hot water storage type hot water supply system 1 in the information acquisition means 51 (see Figure 2 or Figure 4), the virtual heat storage operation cost calculation means 58 (see Figure 2 or Figure 4), the information acquisition flow executed by the information acquisition means 51 (see Figure 3 or Figure 5), and the virtual heat storage operation cost calculation flow executed by the virtual heat storage operation cost calculation means 58 (see Figure 3 or Figure 5).

[0133] The information acquisition means 51 executes an information acquisition flow in (S1). In the information acquisition flow, in addition to information on the amount of heat stored at a certain time, the predicted heat demand at each of a plurality of predicted times after the certain time, and the unit price of electricity by time period for electricity consumed by the heating means 2, information on the predicted amount of surplus electricity from solar power generation by time period and the purchase price of surplus solar electricity by time period is further acquired.

[0134] In addition, if the solar surplus electricity purchase price by time period is a uniform price regardless of the time period and is not changed frequently, it may be stored in a memory or storage device provided in the control means 4 rather than being acquired by the information acquisition means 51, and may be changed appropriately as needed.

[0135] The virtual thermal storage operation cost calculation means 58 executes a virtual thermal storage operation cost calculation flow in (S8). In the virtual thermal storage operation cost calculation flow, for each of a plurality of patterns of virtual thermal storage operation, the product of the amount of power that can be covered by the predicted surplus power of photovoltaic power generation in the time slot of the predicted time out of the amount of power consumed by the heating means 2 at each predicted time from the start time to a predetermined operation time is calculated, and the solar surplus power purchase price in the time slot of the predicted time.

[0136] In principle, the surplus electricity generated by a solar power generation system that is consumed by the power load 100 of a house or the like is purchased at the solar surplus electricity purchase price. Therefore, the amount of electricity consumed by the heating means 2 in virtual thermal storage operation that can be covered by the predicted surplus electricity would have been purchased if this electricity had not been used in virtual thermal storage operation, but since it was not purchased because the hot water storage type hot water supply system 1 consumed it itself, the fee that would have been purchased is considered to be recorded as an expense for virtual thermal storage operation.

[0137] Furthermore, in the virtual thermal storage operation cost calculation flow, for each of a plurality of patterns of virtual thermal storage operation, the product of the amount of power that cannot be covered by the predicted surplus power of solar power generation in the time slot of the predicted time out of the amount of power consumed by the heating means 2 at each predicted time between the start time and the specified operation time is calculated, and the unit price of electricity in the time slot of the predicted time. That is, the amount of power that cannot be covered by the predicted surplus power out of the amount of power consumed by the heating means 2 in the virtual thermal storage operation is covered by the commercial power source 90, as in the hot water storage type hot water supply systems 1 of the first and second embodiments, and therefore the fee calculated by the product of the amount of power that cannot be covered by the predicted surplus power and the unit price of electricity in the time slot of the predicted time is recorded as the cost of the virtual thermal storage operation.

[0138] Then, in the virtual thermal storage operation cost calculation flow, a time-slot cost is calculated as the sum of the product of the amount of power that can be covered by the predicted surplus power amount and the solar surplus power purchase price for the time slot of the predicted time, and the product of the amount of power that cannot be covered by the predicted surplus power amount and the electricity unit price for the time slot of the predicted time. Since this time-slot cost is calculated for each time slot of the predicted time, the time-slot costs for the time slots of each predicted time are summed to calculate the virtual thermal storage operation cost.

[0139] (4.3) Summary of the third embodiment In a hot water storage system 1 that uses electricity generated by a solar power generation system in addition to commercial electricity, the cost-benefit ratio of virtual heat storage operation can be accurately calculated, and heat storage operation with good cost performance can be performed.

[0140] (5) Fourth embodiment A hot water storage type hot water supply system 1 of the fourth embodiment will be described with reference to Figures 7 to 9. Note that the hot water storage type hot water supply system 1 of the fourth embodiment is largely the same as the hot water storage type hot water supply systems 1 of the first to third embodiments shown in Figure 1, and therefore the same components are given the same reference numerals and description thereof will be omitted. Below, differences from the hot water storage type hot water supply systems 1 of the first to third embodiments will mainly be described.

[0141] (5-1) Gas heating means As shown in Fig. 7, the storage type hot water supply system 1 of the fourth embodiment differs from the storage type hot water supply systems 1 of the first to third embodiments in that it includes a gas heating means 11 that meets heat demand by heating through the combustion of gas, in addition to the heating means 2. Specifically, the gas heating means 11 is arranged in the hot water outlet pipe 33, upstream of the branch point of the hot water supply pipe 331 and the hot water filling pipe 332, and downstream of the three-way valve 333.

[0142] (5-2) Information acquisition means The storage type hot water supply system 1 of the fourth embodiment is different from the storage type hot water supply systems 1 of the first to third embodiments in the information acquisition means 51.

[0143] The information acquisition means 51 executes an information acquisition flow in (S1). In the information acquisition flow, in addition to information on the amount of heat stored at a certain time, the predicted heat demand at each of a plurality of predicted times after the certain time, and the unit price of electricity by time period for electricity consumed by the heating means 2, information on the boiler efficiency and gas unit price of the gas heating means 11 is further acquired.

[0144] In addition, since the boiler efficiency and gas unit price of the gas heating means 11 are not set in detail like the electricity unit price by time of day, and are not changed frequently, they may not be acquired by the information acquisition means 51, but may be stored in a memory or storage device provided in the control means 4, and may be changed appropriately as needed.

[0145] (5-3) Gas heating operating cost calculation method As shown in FIG. 8, the hot water storage type hot water supply system 1 of the fourth embodiment differs from the hot water storage type hot water supply systems 1 of the first to third embodiments in that it further includes gas heating operation cost calculation means 64.

[0146] As shown in Fig. 9, in (S31), the gas heating operation cost calculation means 64 executes a gas heating operation cost calculation flow. In the gas heating operation cost calculation flow, the gas heating operation cost is calculated by dividing the total effective heat amount of the virtual thermal storage operation selected by the virtual thermal storage operation selection means 60 by the boiler efficiency of the gas heating means 11 and multiplying the result by the gas unit price. Note that (S21) to (S30) in Fig. 9 are substantially the same as (S1) to (S10) in Fig. 3, so their explanation will be omitted.

[0147] The boiler efficiency is set to 0.9 in this embodiment, but may be set to a value in the range of 0.8 or more and 1 or less, and is not particularly limited to this value.

[0148] The gas heating operation cost calculation means 64 calculates the gas heating operation cost when the gas heating operation is performed instead of the virtual thermal storage operation.

[0149] (5-4) Virtual thermal storage operation suitability determination means The hot water storage type hot water supply system 1 of the fourth embodiment differs from the hot water storage type hot water supply systems 1 of the first to third embodiments in that it further includes virtual recuperation operation suitability determination means 65.

[0150] 9, in (S32), the virtual heat storage operation suitability determination means 65 executes a virtual heat storage operation suitability determination flow. In the virtual heat storage operation suitability determination flow, if the gas heating operation cost is lower than the virtual heat storage operation cost of the virtual heat storage operation selected by the virtual heat storage operation selection means 60, it is determined to be inappropriate, and the control means 4 does not perform the virtual heat storage operation.

[0151] Furthermore, when this embodiment is extended to the repeated calculation of the second embodiment, after determining whether the virtual heat storage operation is appropriate in (S32), (3.1) updating the predicted heat storage amount, (3.2) updating the predicted heat load, and (3.3) determining whether repeated calculation is necessary are performed, as in the second embodiment. However, if the virtual heat storage operation is not appropriate, only (3.1) updating the predicted heat storage amount is not performed.

[0152] (5.5) Summary of the fourth embodiment In a hot water storage type hot water supply system 1 having a heating means 2 that operates on electricity as well as a gas heating means 11 that heats by burning gas, the cost-effectiveness of the two heating means can be accurately compared, and when inappropriate heat storage operation is not performed and the amount of stored heat becomes insufficient, the heat demand is automatically met by the gas heating means 11, so the heat demand can be met with high cost performance.

[0153] (6) How to use the storage-type hot water supply system Next, how to use the hot water storage type hot water supply system 1 will be described.

[0154] (6.1) First usage method In the first usage method, the electricity unit price for all time periods acquired by the information acquisition means 51 is changed to the same amount. In this case, the cost-effectiveness ratio for each virtual thermal storage operation reflects the effects of the effective heat amount, loss due to heat radiation, and start-up / shutdown loss, and by selecting a virtual thermal storage operation with a high cost-effectiveness ratio, it is possible to easily select an energy-saving operation with small loss due to heat radiation and start-up / shutdown loss.

[0155] (6.2) Second usage method In the second usage method, the electricity unit price for a time period when commercial electricity is in short supply, which is acquired by the information acquisition means 51, is changed to a price higher than the maximum electricity unit price for that time period. This makes it easier to avoid heat storage operation during times when electricity is in short supply.

[0156] (6.3) Third usage method In the third usage method, the electricity unit price for a time period when there is surplus commercial electricity is changed to an amount lower than the minimum electricity unit price for that time period, for the electricity unit price for each time period acquired by the information acquisition means 51. This makes it easier to induce heat storage operation during times when there is surplus electricity.

[0157] The above-described embodiments are merely a few of the various embodiments of the present invention. Furthermore, the embodiments can be modified in various ways depending on the design and the like as long as the object of the present invention can be achieved. [Explanation of symbols]

[0158] 1. Storage-type hot water supply system 100 power load 2 Heating means 3 Heat storage tank 31 Main heating medium circuit 32 Heat recovery heat exchanger 33 Outlet pipe 331 Hot Water Pipe 332 Hot water pipe 333 Three-way valve 34 Heat exchanger 35 parallel flow paths 36 Reheating circulation circuit 37 Bathtub 4. Control measures 41 Operation section 50 Processing section 51 Information acquisition means 52 Means for calculating effective heat quantity and predicted heat storage quantity 53 Predicted heat load calculation method 54 Additional heat storage calculation means 55 Means for calculating effective heat amount and predicted additional heat storage amount 56 Excessive heat storage determination means 57 Total effective heat amount calculation method 58 Virtual thermal storage operating cost calculation method 59 Cost-effectiveness calculation method 60 Virtual heat storage operation selection means 61 Predicted heat storage update means 62 Predicted heat load update method 63 Means for determining whether repeated calculation is necessary 64 Gas heating operating cost calculation method 65 Virtual heat storage operation suitability determination means 7 Network 8 Server

Claims

1. A heating means; a heat storage tank that stores the heat generated by the heating means as hot water; a control means for controlling the heating means to perform a heat storage operation for increasing the amount of heat stored in the heat storage tank; an information acquisition means for acquiring information on the amount of heat stored at a certain time, predicted heat demand at each of a plurality of predicted times after the certain time, and the unit price of electricity consumed by the heating means by time period; an effective heat quantity and predicted heat storage quantity calculation means for setting the heat storage quantity at the one time as a predicted heat storage quantity at the same time as the one time, and calculating, from the predicted heat storage quantity and the predicted heat demand at each of a plurality of predicted times after the one time, the amount of the predicted heat storage quantity at the predicted time that will be consumed by the predicted heat demand at the predicted time as an effective heat quantity, and calculating the remaining amount of the predicted heat storage quantity at the predicted time as the predicted heat storage quantity at the next predicted time; a predicted heat load calculation means for calculating a value obtained by subtracting the available heat quantity at the predicted time from the predicted heat demand at the predicted time, and setting the calculated value as a predicted heat load at the predicted time; an additional heat storage amount calculation means for calculating an additional heat storage amount to be stored due to the virtual heat storage operation, for each of a plurality of patterns of the virtual heat storage operation having different start times, when it is assumed that the virtual heat storage operation is performed for a predetermined operation time from one start time after the one time; an effective additional heat amount and predicted additional heat storage amount calculation means for calculating, in each of the plurality of patterns of virtual heat storage operation, the additional heat storage amount at the start time after the one time as a predicted additional heat storage amount at the same time as the start time, and calculating, from the predicted additional heat storage amount and the predicted heat load at each of a plurality of predicted times after the one time, the amount of the predicted additional heat storage amount at the predicted time that will be consumed by the predicted heat load at the predicted time as an effective additional heat amount, and calculating the remaining amount of the predicted additional heat storage amount at the predicted time as the predicted additional heat storage amount at the next predicted time; a total effective heat amount calculation means for calculating a total effective heat amount by summing up the effective heat amounts at each predicted time in each of the plurality of patterns of the virtual heat storage operation; a virtual thermal storage operation cost calculation means for calculating a virtual thermal storage operation cost by summing up a time-zone cost obtained by multiplying the amount of power consumed by the heating means at each predicted time between the start time and the predetermined operation time by the unit price of power in the time zone of the predicted time in each of the plurality of patterns of virtual thermal storage operation; an effectiveness-cost calculation means for calculating an effectiveness-cost by dividing the total effective heat amount by the virtual thermal storage operation cost in each of the plurality of patterns of the virtual thermal storage operation; a virtual thermal storage operation selection means for comparing the cost-effectiveness of each of the plurality of patterns of the virtual thermal storage operation and selecting the virtual thermal storage operation for which the cost-effectiveness is highest; the control means executes the virtual heat storage operation selected by the virtual heat storage operation selection means as the heat storage operation. Storage-type hot water supply system.

2. The hot water storage type hot water supply system further includes a heat storage excess determination means, the heat storage excess determination means determines that one of the virtual heat storage operations is inappropriate when a sum of the predicted heat storage amount and the predicted additional heat storage amount at any of the predicted times exceeds a predetermined value that is equal to or less than the maximum heat storage amount of the heat storage tank, and excludes the virtual heat storage operation from selection targets of the virtual heat storage operation selection means. The hot water storage type hot water supply system according to claim 1.

3. The additional heat storage amount calculation means calculates the additional heat storage amount for each of the plurality of patterns of virtual heat storage operation, with each predicted time up to the predicted time immediately before the predicted time at which the predicted heat load first becomes positive, among the plurality of predicted time points having a predetermined time interval as the start time. The hot water storage type hot water supply system according to claim 1 or 2.

4. The hot water storage type hot water supply system further includes a predicted heat storage amount updating means and a predicted heat load updating means, the predicted heat storage amount updating means sets the virtual heat storage operation selected immediately before by the virtual heat storage operation selecting means as a previous virtual heat storage operation, and updates the predicted heat storage amount at each of the plurality of prediction times by adding the predicted additional heat storage amount in the previous virtual heat storage operation to the immediately previous predicted heat storage amount, the predicted heat load update means updates the predicted heat load at each of the plurality of predicted times by subtracting the effective heat amount in the previous virtual heat storage operation from the immediately preceding predicted heat load, and The virtual thermal storage operation to be selected is additionally selected by the operations of the additional thermal storage amount calculation means, the effective additional heat amount and predicted additional thermal storage amount calculation means, the total effective additional heat amount calculation means, the virtual thermal storage operation cost calculation means, the effectiveness-cost calculation means, and the virtual thermal storage operation selection means. The hot water storage type hot water supply system according to claim 1 or 2.

5. The hot water storage type hot water supply system further includes a means for determining whether repeated calculation is necessary, The means for determining whether or not iterative calculation is necessary is If the predicted heat loads at the plurality of predicted times within a predetermined period are all 0, the calculation is terminated. If there is a positive predicted thermal load at the plurality of predicted times within a predetermined period, a new virtual thermal storage operation is selected. The hot water storage type hot water supply system according to claim 4.

6. The information acquisition means further acquires information on the predicted surplus power amount of solar power generation by time period and the purchase price of the surplus solar power by time period, The virtual thermal storage operating cost calculation means In each of the plurality of patterns of virtual thermal storage operation, the product of the amount of power that can be covered by the predicted surplus power amount of photovoltaic power generation in the time period of the predicted time out of the amount of power consumed by the heating means at each predicted time from the start time to the predetermined operation time and the solar surplus power purchase price in the time period of the predicted time, and calculating a virtual thermal storage operation cost by summing up time-zone costs consisting of the sum of the product of the amount of power that cannot be covered by the predicted surplus power amount of photovoltaic power generation in the time zone of the prediction time among the amount of power consumed by the heating means at each prediction time from the start time to the predetermined operation time and the unit price of power in the time zone of the prediction time. The hot water storage type hot water supply system according to claim 1 or 2.

7. The hot water storage type hot water supply system includes: A gas heating means is provided separately from the heating means for heating by burning gas to meet heat demand, the information acquisition means further acquires information on the boiler efficiency of the gas heating means and the gas unit price, calculating a gas heating operation cost by dividing the total effective heat amount of the virtual thermal storage operation selected by the virtual thermal storage operation selection means by the boiler efficiency of the gas heating means and multiplying the result by the gas unit price; When the gas heating operation cost is lower than the virtual thermal storage operation cost of the virtual thermal storage operation selected by the virtual thermal storage operation selection means, the virtual thermal storage operation is determined to be inappropriate; the control means does not execute the virtual heat storage operation selected by the virtual heat storage operation selection means as the heat storage operation; The hot water storage type hot water supply system according to claim 1 or 2.

8. A method for using the hot water storage type hot water supply system according to claim 1 or 2, Regarding the time-zone-specific electricity unit prices acquired by the information acquisition means, changing the electricity unit prices for all time zones to the same amount; How to use a storage hot water system.

9. A method for using the hot water storage type hot water supply system according to claim 1 or 2, The information acquisition means additionally acquires information about time periods when commercial power is tight; Regarding the time-zone-specific electricity unit prices acquired by the information acquisition means, the electricity unit price for the time zone in which commercial electricity is tight is changed to an amount higher than the maximum electricity unit price for the time zone. How to use a storage hot water system.

10. A method for using the hot water storage type hot water supply system according to claim 1 or 2, The information acquisition means additionally acquires information about time periods when there is surplus commercial power; Regarding the electricity unit prices for each time period acquired by the information acquisition means, the electricity unit price for the time period in which there is surplus commercial electricity is changed to an amount lower than the minimum electricity unit price for each time period. How to use a storage hot water system.

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