Hot water storage and supply system

Abstract

Provided is a hot water storage and supply system capable of promoting high energy efficiency hot water storage. A hot water storage and supply system (1) includes a hot water storage tank (21), a heat source machine (10) that stores heated hot water in the hot water storage tank, a hot water discharge passage (27) for discharging hot water from the hot water storage tank, a hot water discharge heat quantity detection means for the hot water discharge passage, a stored hot water heat quantity detection means for detecting a stored hot water heat quantity in the hot water storage tank, and a control means (29) for predicting a required heat quantity for each predetermined time period on the basis of hot water discharge results and storing the required heat quantities included in a predetermined period, wherein: the control means sets, as a storable heat quantity for each time period, the smaller of the stored hot water heat quantity planned at the end point of each time period and the maximum stored hot water heat quantity in the hot water storage tank; if the storable heat quantities are each equal to or greater than the corresponding required heat quantity, the control means sets the heat source machine output and the stored hot water temperature so as to maximize a coefficient of performance; and if any of the storable heat quantities is less than the corresponding required heat quantity, the control means sets the heat source machine output and the stored hot water temperature in accordance with a determination of whether the output of the heat source machine is insufficient or the maximum stored hot water heat quantity has been reached.

Description

Hot water storage system

[0001] This invention relates to a household hot water supply system that predicts future hot water usage based on past hot water usage data and stores hot water in a storage tank according to this prediction.

[0002] Traditionally, hot water supply systems using heat pumps as the heat source have been widely employed. These systems store heated water in a storage tank, and the stored water is then used for hot water supply. For example, some systems use inexpensive off-peak electricity to store water for the next day overnight, while others store the amount of heat needed for future hot water use, based on past hot water usage data, before the water is used.

[0003] For example, in Patent Document 1, the required amount of heat to heat water for the next day is calculated based on the remaining amount of hot water in the hot water storage tank, the storage temperature, and the average temperature of the tap water, and the start time for storing the hot water is set according to the time it takes to store this required amount of heat. In this case, if the required amount of heat to heat water cannot be stored during a time when electricity rates are low, either the storage temperature or the output of the heat source unit is changed to fill the hot water storage tank with heated water.

[0004] Furthermore, Patent Document 2 calculates the amount of heat required to heat the water based on the stored hot water output history and the residual heat amount in the hot water storage tank. The hot water storage temperature is set according to this required heat amount, and the heating capacity of the heat source is set according to the hot water storage temperature. If the residual heat amount is greater than the standard value, the water is stored at the minimum heating capacity regardless of the required heat amount.

[0005] Patent No. 3982416 Patent No. 7226062

[0006] The hot water storage systems described in Patent Documents 1 and 2 store hot water in a large-capacity storage tank to prevent running out of hot water. However, the heat loss from storing high-temperature hot water in this storage tank until it is dispensed is significant. Therefore, a hot water storage system is known in which a heat pump type heat source unit heats the predicted amount of heat based on past hot water dispensing data by the predicted time of dispensing and stores it in the storage tank. Normally, this stored hot water is used for hot water supply, and if the stored hot water is insufficient, hot water heated by a combustion-type auxiliary heat source unit is supplied. Because the required amount of heat is stored each time, heat loss is reduced, the storage tank can be made smaller, and because an auxiliary heat source unit is provided, situations where hot water cannot be dispensed are prevented.

[0007] Heat pump-type heat sources are more energy-efficient than auxiliary heat sources, so increasing the proportion of hot water stored in a heat pump-type heat source improves energy efficiency and reduces running costs. However, since the capacity of the hot water storage tank is limited, increasing the proportion of hot water stored must be done by raising the storage temperature or increasing the output of the heat source while storing and dispensing hot water. Generally, the lower the output of a heat source and the lower the storage temperature, the better the coefficient of performance (COP), which is an indicator of energy efficiency. Therefore, raising the storage temperature and increasing the output of the heat source will lower the coefficient of performance of the heat source, and doing so more than necessary may actually decrease energy efficiency.

[0008] Therefore, in view of the above-mentioned problems, the present invention aims to provide a hot water storage and supply system that can promote highly energy-efficient hot water storage.

[0009] The hot water storage system of the invention of claim 1 comprises a hot water storage tank for storing hot water, a heat source unit that performs a hot water storage operation to heat the hot water in the hot water storage tank and store it in the hot water storage tank, a hot water outlet passage for dispensing hot water from the hot water storage tank, a hot water outlet heat amount detection means for detecting the amount of heat discharged from the hot water outlet passage, a hot water storage heat amount detection means for detecting the amount of heat stored in the hot water storage tank, and a control means that predicts the required amount of heat for each time period divided into predetermined unit time intervals based on the amount of heat discharged and the hot water discharge record including the time of discharge detected by the hot water outlet heat amount detection means, and controls the hot water storage operation to store the sum of the required heat amounts for a predetermined period. In this system, the control means is configured such that, during hot water storage operation, it sets the amount of heat that can be stored for each time period to be the smaller of the amount of heat that is scheduled to be stored at the end of each time period or the maximum amount of heat that can be stored in the hot water storage tank, and if either of these amounts of heat that can be stored is equal to or greater than the required amount of heat for the corresponding time period, it sets the output of the heat source unit and the hot water storage temperature so as to maximize the coefficient of performance of the heat source unit, and if either of the amounts of heat that can be stored is less than the required amount of heat for the corresponding time period, it sets the output of the heat source unit and the hot water storage temperature according to the determination of whether the output of the heat source unit is insufficient or the maximum amount of heat that can be stored has been reached.

[0010] According to the above configuration, the hot water storage and supply system predicts the required heat amount for each time period divided into predetermined unit time intervals based on past hot water output records, and stores the total required heat amount for the predetermined period. At this time, if the amount of heat that can be stored at the end of each time period is equal to or greater than the required heat amount for each time period, the system sets the output of the heat source unit and the hot water storage temperature to maximize the coefficient of performance of the heat source unit and performs hot water storage operation. On the other hand, if the amount of heat that can be stored at the end of each time period is less than the required heat amount for each time period, the system determines whether the cause of the decrease is insufficient output of the heat source unit or reaching the maximum hot water storage heat capacity limited by the hot water storage tank, and sets the output of the heat source unit and the hot water storage temperature according to the cause. Therefore, when it is possible to store the required amount of hot water, it can be stored with high energy efficiency, and when it is not possible to store the required amount of hot water, the output of the heat source unit and the hot water storage temperature can be set according to the cause to mitigate the decrease in energy efficiency.

[0011] The hot water storage and supply system of the invention of claim 2 is characterized in that, in the invention of claim 1, the control means is configured such that, when both insufficient output of the heat source unit and the maximum amount of hot water storage heat have been reached, the heat source unit is determined to be insufficient output if the current amount of hot water storage heat is less than a preset standard value, and the maximum amount of hot water storage heat has been reached if the current amount of hot water storage heat is equal to or greater than the standard value. With the above configuration, when both insufficient output and the maximum amount of hot water storage heat have been reached, it is possible to easily determine whether there is insufficient output or the maximum amount of hot water storage heat has been reached based on the current amount of hot water storage heat.

[0012] The hot water storage and supply system of claim 3 is characterized in that, in the invention of claim 1 or 2, the control means is configured to set the hot water storage temperature to a preset upper limit temperature when it is determined that the maximum hot water storage heat capacity has been reached, and to set the output of the heat source unit to the minimum output that can reach the maximum hot water storage heat capacity of the hot water storage tank. According to the above configuration, if the amount of hot water required to reach the maximum hot water storage heat capacity cannot be stored, the output of the heat source unit is set to the minimum output that can reach the maximum hot water storage heat capacity, thereby delaying the arrival of the maximum hot water storage heat capacity. Since the coefficient of performance of the heat source unit improves as the output decreases, the decrease in energy efficiency can be reduced even if the hot water storage temperature is at the upper limit temperature.

[0013] The hot water storage and supply system of claim 4 is characterized in that, in the invention of claim 1 or 2, when the control means determines that the output of the heat source is insufficient, it sets the hot water storage temperature to a lower limit temperature corresponding to the hot water supply set temperature and sets the output of the heat source to a predetermined maximum output. According to the above configuration, when the required amount of hot water cannot be stored due to insufficient output of the heat source, the output of the heat source is maximized and the hot water storage temperature is set to a lower limit temperature at which hot water can be dispensed at the hot water supply set temperature, thereby quickly supplying hot water that can be dispensed at the hot water supply set temperature to the hot water storage tank. As the coefficient of performance of the heat source improves as the hot water storage temperature decreases, the decrease in energy efficiency can be mitigated even when the heat source is at maximum output.

[0014] According to the hot water storage and supply system of the present invention, it is possible to promote highly energy-efficient hot water storage.

[0015] This is a diagram showing the configuration of a hot water storage and supply system according to an embodiment of the present invention. This is a diagram showing the prediction of the required heat amount according to the embodiment. This is a flowchart for setting the hot water storage conditions according to the embodiment.

[0016] The embodiments for carrying out the present invention will be described below based on examples.

[0017] First, the hot water storage and supply system 1 will be described based on Figure 1. The hot water storage and supply system 1 includes a heat pump type main heat source unit 10 (heat source unit), a hot water storage unit 20 equipped with a hot water storage tank 21, and an auxiliary heat source unit 40. The auxiliary heat source unit 40 is, for example, a combustion type heat source unit, and supplies hot water supplied from the hot water storage unit 20 via the hot water passage 41 to a hot water supply passage 42, for example, a hot water tap 8, either by reheating it according to its temperature or without reheating it.

[0018] At the bottom of the hot water storage tank 21, a main heat source supply passage 23 equipped with a pump 22 is connected to supply hot water from the hot water storage tank 21 to the main heat source unit 10. At the top of the hot water storage tank 21, a main heat source return passage 24 is connected to return the hot water heated by the main heat source unit 10 back to the hot water storage tank 21. A switching valve 25 is installed in the middle of the main heat source return passage 24 to switch the flow path of the hot water, and a return branch passage 24a, which branches off from the main heat source return passage 24 by the switching valve 25, is connected to the upstream portion of the main heat source supply passage 23 beyond the pump 22.

[0019] Upstream of the switching valve 25 in the main heat source return passage 24, a return temperature sensor 24b is installed to detect the temperature of the hot water heated by the main heat source 10. For example, if the temperature detected by the return temperature sensor 24b is low immediately after starting up the main heat source 10, the switching valve 25 is switched from the hot water storage tank 21 side to the return branch passage 24a side, and the hot water is circulated without being returned to the hot water storage tank 21 until it can be heated sufficiently.

[0020] A water supply passage 26 for supplying tap water is connected to the bottom of the hot water storage tank 21, as indicated by the arrow CW. A hot water outlet passage 27 for discharging the hot water from the hot water storage tank 21 to the hot water storage unit 20 is connected to the top of the hot water storage tank 21. A water supply branch passage 26a, which branches off from the water supply passage 26, is connected to a mixing valve 28 located in the middle of the hot water outlet passage 27. Multiple hot water storage temperature sensors 21a to 21d are installed in the hot water storage tank 21, which can detect the temperature and amount of hot water stored in the hot water storage tank 21. These hot water storage temperature sensors 21a to 21d correspond to the hot water heat quantity detection means.

[0021] A water supply temperature sensor 26b is installed in the water supply passage 26 to detect the temperature of the tap water supplied from the water supply passage 26 (water supply temperature). A hot water outlet passage 27 is installed in the hot water outlet passage 27, a hot water storage tank outlet temperature sensor 27b, and a hot water outlet temperature sensor 27c. The hot water outlet flow rate sensor 27a detects the flow rate of hot water from the hot water storage unit 20. The hot water storage tank outlet temperature sensor 27b detects the temperature of the hot water dispensed from the hot water storage tank 21 (hot water storage tank outlet temperature). The hot water outlet temperature sensor 27c detects the temperature of the hot water dispensed from the hot water storage unit 20. Based on the flow rate of hot water dispensed by the hot water outlet flow rate sensor 27a and the temperature of hot water dispensed by the hot water outlet temperature sensor 27c, the amount of heat from the dispensed hot water is detected (calculated). The hot water outlet flow rate sensor 27a and the hot water outlet temperature sensor 27c correspond to the means for detecting the amount of heat from the dispensed hot water.

[0022] The hot water outlet passage 27 of the hot water storage unit 20 and the water inlet 40a of the auxiliary heat source unit 40 are connected by a hot water passage 41. The hot water outlet 40b of the auxiliary heat source unit 40 is connected to a hot water supply passage 42 which is connected to a hot water tap 8. The hot water dispensed from the hot water storage unit 20 is supplied to the hot water tap 8 via the auxiliary heat source unit 40, and hot water is supplied from the hot water tap 8 as indicated by the arrow HW.

[0023] The hot water storage unit 20 has a control unit 29 (control means) for controlling a hot water storage operation of driving a pump 22 to circulate hot water between a hot water storage tank 21 and the main heat source machine 10, and storing the hot water heated by the main heat source machine 10 from the upper part of the hot water storage tank 21. Based on the hot water outlet temperature from the hot water storage tank, the feed water temperature, and the hot water outlet flow rate, this control unit 29 adjusts the mixing ratio in the mixing valve 28 so that the temperature detected by the hot water outlet temperature sensor 27c becomes, for example, a preset hot water supply set temperature or a predetermined temperature, and discharges the hot water. The predetermined temperature is set so that the auxiliary heat source machine 40 can heat the hot water supplied from the hot water storage unit 20 to the hot water supply set temperature for hot water supply.

[0024] For example, on an indoor wall portion such as in a kitchen, there is provided an operation terminal 30 having a display unit for displaying information related to hot water supply and hot water storage operations and the like, and for performing setting operations such as setting the hot water supply set temperature. This operation terminal 30 is communicably connected to the auxiliary heat source machine 40 and is configured to be able to supply hot water at the hot water supply set temperature set by the operation terminal 30 to the hot water tap 8. Further, the operation terminal 30 is communicably connected to the control unit 29 of the hot water storage unit 20 via the auxiliary heat source machine 40 and can perform setting operations related to the hot water storage operation.

[0025] The control unit 29 has a function of learning and storing, as the hot water outlet actual result, the hot water outlet time from the hot water storage unit 20 during hot water supply, the hot water outlet flow rate detected by the hot water outlet flow rate sensor 27a, and the hot water outlet heat amount calculated from the hot water outlet temperature detected by the hot water outlet temperature sensor 27c. Then, as shown in, for example, FIG. 2, based on the learned past hot water outlet actual results, it predicts the required heat amount for each time zone divided by a predetermined unit time (for example, 1 hour) for future hot water supply use, and controls the hot water storage operation based on this required heat amount.

[0026] The control unit 29 acquires the current hot water storage heat amount of the hot water storage tank 21, and sums up the required heat amounts for the time zones corresponding to a first period T1 of a predetermined length from the next time zone of the time zone to which the current time belongs, and calculates a first heat amount. When the required heat amount is predicted as shown in FIG. 2 and the current time is 16:00, the control unit 29 acquires the current hot water storage heat amount of the hot water storage tank 21 and the time zone A in the 16:00 hour range １ of the next time zone A ２From 17:00 to 20:00 corresponding to the first period T1 (for example, 3 hours), time zone A ２ ~A ４ The required heat amounts (prediction 1, prediction 2) are summed up to calculate the first heat amount. And when the first heat amount is greater than the current stored hot water heat amount, the startup condition of the main heat source machine 10 is satisfied, and the main heat source machine 10 is started to begin the stored hot water operation.

[0027] Also, for time zone A of 16:00 to which the current time belongs １ The next time zone A ２ The required heat amounts (prediction 1, prediction 2, prediction 3, prediction 4) for the second period T2 (from 16:00 to 23:00) with a predetermined length (for example, 7 hours) longer than the first period T1 are summed up to calculate the second heat amount. And when the second heat amount becomes less than or equal to the current stored hot water heat amount, the stop condition of the main heat source machine 10 is satisfied, and the main heat source machine 10 is stopped to end the stored hot water operation. Also, when the current stored hot water heat amount reaches the maximum heat amount (maximum stored hot water heat amount) that can be stored in the hot water storage tank 21, the stored hot water operation is ended.

[0028] The control unit 29 sets stored hot water conditions for storing the required heat amount at the start of the stored hot water operation. This setting of the stored hot water conditions will be described based on the flowchart of FIG. 3. Si (i = 1, 2,...) in the figure represents steps.

[0029] First, in S1, the value of the variable n for counting the time zone is initialized to zero, and it proceeds to S2. And in S2, the stored hot water heat amount of the current hot water storage tank 21 is acquired and it proceeds to S3. Next, in S3, the value of the variable n is increased by 1 and it proceeds to S4.

[0030] In S4, for time zone A ｎ The possible heat amount Q ｎ in it is determined whether it is greater than or equal to the required heat amount R ｎ in this time zone A ｎ Here, since the hot water storage tank 21 cannot store a heat amount exceeding its maximum stored hot water heat amount, the possible heat amount Q ｎ is set to the smaller of the predicted stored hot water heat amount at the end of time zone A ｎ or the maximum stored hot water heat amount of the hot water storage tank 21. The predicted stored hot water heat amount at the end of time zone A ｎ is the stored hot water heat amount predicted at the end of time zone Aｎ It is calculated by considering the heat inflow and outflow in the time zone A. ｎ The amount of hot water stored or the amount of heat that can be held at the start Q ｎ－１ From time zone A ｎ Required heat (time period A) ｎ Subtract the amount of heat (expected to be released when the hot water is dispensed) and calculate the time period A ｎ This is the total heat amount obtained by adding the amount of heat that can be stored at the maximum output of the main heat source unit 10.

[0031] In S4, it is determined whether the required amount of heat can be stored for the corresponding time period. If the result of S4 is Yes, the process proceeds to S5, where it is determined whether the value of variable n is 4. If the result of S5 is No, the process returns to S3. As long as the result of S4 is Yes and the result of S5 is No, it is determined whether the required amount of heat for the next time period can be stored. Note that the current time belongs to time period A. １ And the following three time slots A ２ ~A ４ The system determines whether hot water storage is possible, but the number of time periods to be determined (the maximum value of n) is not limited to this; for example, it could be 3, or 5 or more.

[0032] If the result in S5 is Yes, the process proceeds to S6, where the hot water storage temperature and the output of the main heat source unit 10 are set to maximize the coefficient of performance (COP), and the hot water storage condition setting is completed. This allows for hot water storage operation with high energy efficiency, enabling the storage of the required amount of heat, and promoting highly energy-efficient hot water storage.

[0033] On the other hand, if the result of S4 is No, the process proceeds to S7, where the amount of heat that can be held Q is determined. ｎ Required heat quantity R ｎ The system determines whether reaching the maximum amount of heat storage capacity that can be stored in the hot water storage tank 21 during this time period is one of the reasons why the required amount of heat storage capacity cannot be achieved. If the determination in S7 is Yes, the system proceeds to S8, where it is determined whether insufficient output from the main heat source unit 10 is one of the reasons why the required amount of heat storage capacity cannot be achieved.

[0034] If the determination in S8 is Yes, the process proceeds to S9, where it is determined whether the amount of heat that can be held in any of the previous time periods is equal to the maximum amount of hot water that can be stored. This step determines whether the maximum amount of hot water that can be stored has already been reached at the start of this time period. The previous time period refers to a time period prior to the time period in which it was determined that the required amount of hot water could not be stored, for example, time period A ３ Time period A when it is determined that the required amount of hot water cannot be stored. １ , A ２ It is a time zone that is earlier than the time zone to which the current time belongs. Therefore, time zone A １ In this case, the judgment in S9 is No. If the judgment in S9 is No, the process proceeds to S10, where it is determined whether the current amount of stored hot water heat is equal to or greater than a preset standard value. The standard value is set, for example, to 70% of the maximum amount of stored hot water heat in the hot water storage tank 21, but is not limited to this, and can be set based on the heating capacity of the main heat source unit 10 and the capacity of the hot water storage tank 21, etc.

[0035] If the judgment in S10 is Yes, if the judgment in S9 is Yes, or if the judgment in S8 is No (not due to insufficient output), the process proceeds to S11. In S11, the reason why the required amount of hot water cannot be stored is determined to be reaching the maximum hot water storage capacity, and the process proceeds to S12. In S12, the hot water storage temperature is set to the upper limit temperature predetermined as a specification, and the minimum output of the main heat source unit 10 that can reach the maximum hot water storage capacity during this time period is set to complete the hot water storage condition setting. The lower the output of the main heat source unit 10 and the lower the hot water storage temperature, the higher the coefficient of performance (COP). Therefore, until the maximum hot water storage capacity is reached, the decrease in COP due to the hot water storage temperature being set to the upper limit temperature is mitigated, promoting highly energy-efficient hot water storage.

[0036] If the result of S7 is No (indicating insufficient output), the process proceeds to S13, where it is determined whether the amount of heat that can be held in any of the previous time periods is equal to the maximum amount of hot water that can be stored. The previous time period refers to a time period prior to the time period in which it was determined that the required amount of hot water could not be stored, as in S9 above, and is not a time period prior to the time period to which the current time belongs. Therefore, time period A １In this case, the judgment in S13 is No. If the judgment in S13 is Yes, proceed to S11, where the reason why the required amount of hot water cannot be stored is determined to be reaching the maximum amount of hot water storage capacity, and proceed to S11. The process from S11 onwards is the same as above, so the explanation is omitted.

[0037] If the determination in S13 is No, or if the determination in S10 is No, the process proceeds to S14, where it is determined that the reason why the required amount of hot water cannot be stored is insufficient output from the main heat source unit 10, and the process proceeds to S15. In S15, the hot water storage temperature is adjusted to the hot water supply set temperature to set the lower limit temperature at which hot water can be dispensed, i.e., the lower limit temperature corresponding to the hot water supply set temperature, and the maximum output of the main heat source unit 10 is set to complete the hot water storage condition setting. The lower the output of the main heat source unit 10 and the lower the hot water storage temperature, the higher the coefficient of performance (COP). Therefore, the decrease in COP due to setting the output to maximum can be mitigated, while increasing the supply flow rate of hot water that can be dispensed to the hot water storage tank 21, thereby promoting highly energy-efficient hot water storage.

[0038] The operation and effects of the above-described hot water storage and supply system 1 will now be explained. The hot water storage and supply system 1 predicts the required amount of heat for each time period divided into predetermined unit time intervals based on past hot water supply records, and stores the total amount of heat required for the predetermined period. At this time, each time period A ｎ Required heat quantity R ｎ In contrast, the amount of heat that can be held at the end of each time period is Q. ｎ If all of these conditions are equal or better, the output of the main heat source unit 10 and the hot water storage temperature are set to maximize the coefficient of performance (COP) of the main heat source unit 10, and the hot water storage operation is performed. Meanwhile, the required heat quantity R for each time period ｎ In contrast, the amount of heat that can be held at the end of each time period is Q. ｎ If either of these decreases, it is determined whether the cause is insufficient output from the main heat source unit 10 or the limit imposed by the hot water storage tank 21, which is reaching the maximum amount of stored hot water, and the output of the main heat source unit 10 and the hot water storage temperature are set according to the cause. Therefore, the required heat amount R ｎ When hot water storage is possible, hot water can be stored with high energy efficiency, and the required heat amount R ｎ If hot water storage is not possible, the output of the main heat source unit 10 and the hot water storage temperature can be set according to the cause to mitigate the decrease in energy efficiency.

[0039] The control unit 29 controls the required heat R ｎ If the reason for the inability to store hot water is insufficient output of the main heat source unit 10 and the maximum storage capacity has been reached, the system determines whether the main heat source unit 10 is insufficient output or has reached its maximum storage capacity based on the current storage capacity and a preset standard value. If both insufficient output and the maximum storage capacity have been reached are present, it is easy to determine whether the system is insufficient output or has reached its maximum storage capacity based on the current storage capacity.

[0040] The control unit 29 determines the amount of heat R required to reach the maximum hot water storage heat capacity. ｎ If hot water storage is not possible, the output of the main heat source unit 10 is set to the minimum output that can reach the maximum hot water storage heat capacity, delaying the arrival of the maximum hot water storage heat capacity. Since the coefficient of performance (COP) of the main heat source unit 10 improves as the output decreases, the decrease in energy efficiency can be mitigated even if the hot water storage temperature is at the upper limit temperature.

[0041] The control unit 29, when the main heat source unit 10 cannot store the required amount of hot water due to insufficient output, maximizes the output of the main heat source unit 10 and sets the hot water storage temperature to the lower limit temperature at which hot water can be dispensed at the hot water supply set temperature, thereby quickly supplying hot water that can be dispensed at the hot water supply set temperature to the hot water storage tank 21. Since the coefficient of performance (COP) of the main heat source unit 10 improves as the hot water storage temperature decreases, the decrease in energy efficiency can be mitigated even when the main heat source unit 10 is at maximum output.

[0042] Furthermore, those skilled in the art can implement the present invention in various forms with modifications to the above embodiments without departing from the spirit of the invention, and the present invention encompasses such modifications.

[0043] 1: Hot water storage and supply system 8: Hot water tap 10: Main heat source unit (heat source unit) 20: Hot water storage unit 21: Hot water storage tank 21a-21d: Hot water storage temperature sensor (hot water storage heat quantity detection means) 22: Pump 23: Heat source unit supply passage 24: Heat source unit return passage 24a: Return branch passage 24b: Return temperature sensor 25: Switching valve 26: Water supply passage 26a: Water supply branch passage 26b: Water supply temperature sensor 27: Hot water outlet passage 27a: Hot water outlet flow rate sensor 27b: Hot water storage tank outlet temperature sensor 27c: Hot water outlet temperature sensor 28: Mixing valve 29: Control unit (control means) 30: Operation terminal 40: Auxiliary heat source unit 41: Hot and cold water passage 42: Hot water supply passage

Claims

1. A hot water storage and supply system comprising: a hot water storage tank for storing hot water; a heat source unit that performs a hot water storage operation to heat the hot water in the hot water storage tank and store it in the hot water storage tank; a hot water outlet passage for dispensing hot water from the hot water storage tank; a hot water outlet heat amount detection means for detecting the amount of heat discharged from the hot water outlet passage; a hot water storage heat amount detection means for detecting the amount of heat stored in the hot water storage tank; and a control means that predicts the required amount of heat for each time period divided into predetermined unit time intervals based on the amount of heat discharged and the hot water discharge record including the time of discharge detected by the hot water outlet heat amount detection means, and controls the hot water storage operation to store the sum of the required heat amounts for a predetermined period, The control means is configured to set the amount of heat that can be stored for each time period as the smaller of the amount of heat that is scheduled to be stored at the end of each time period or the maximum amount of heat that can be stored in the storage tank, as the amount of heat that can be stored for each time period during the storage operation, and if either of these amounts of heat can be stored is equal to or greater than the required amount of heat for the corresponding time period, the output of the heat source unit and the storage temperature are set so as to maximize the coefficient of performance of the heat source unit, and if either of the amounts of heat that can be stored is less than the required amount of heat for the corresponding time period, the output of the heat source unit and the storage temperature are set according to the determination of whether the output of the heat source unit is insufficient or the maximum amount of heat that can be stored has been reached.

2. The hot water supply system according to claim 1, characterized in that, when both the output of the heat source unit is insufficient and the maximum hot water storage heat capacity has been reached, the control means is configured to determine that the output of the heat source unit is insufficient when the current amount of hot water storage heat is less than a preset standard value, and to determine that the maximum hot water storage heat capacity has been reached when the current amount of hot water storage heat is equal to or greater than the standard value.

3. The hot water storage and supply system according to claim 1 or 2, characterized in that the control means is configured to set the hot water storage temperature to a preset upper limit temperature when it is determined that the maximum hot water storage heat capacity has been reached, and to set the output of the heat source to the minimum output that can reach the maximum hot water storage heat capacity of the hot water storage tank.

4. The hot water storage and hot water supply system according to claim 1 or 2, characterized in that, when the control means determines that the output of the heat source is insufficient, it sets the hot water storage temperature to a lower limit temperature corresponding to the hot water supply set temperature and sets the output of the heat source to a predetermined maximum output.

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