Hot water storage system

Abstract

To provide a hot water storage and supply system capable of stably supplying hot water at a hot water supply set temperature after restarting supply of hot water.SOLUTION: In a hot water storage and supply system (1) having a heat source machine (4) supplying hot water at a hot water supply set temperature by performing a heating operation when hot water supplied from a hot water storage unit (3) including a hot water storage tank (2) has a prescribed heating start temperature or less, the hot water storage unit (3) is provided with: a hot water mixing portion (14) adjusting a temperature by mixing the hot water of the hot water storage tank (2) and clean water and supplying the hot water to the heat source machine (4); hot water supply temperature detection means detecting a hot water supply temperature; stored hot water heat quantity detection means detecting a heat quantity of the stored hot water in the hot water storage tank (2); and a hot water storage unit control portion (18) controlling a hot water supply operation. The hot water storage unit control portion (18) uses, as a target temperature in adjusting the temperature, a hot water supply set temperature in a case when the heat quantity of stored hot water is a reference heat quantity or more, and a heating start temperature when it is less than the reference heat quantity, stores the hot water supply temperature in stopping the hot water supply operation, and uses, as the target temperature, the stored hot water supply temperature regardless of the heat quantity of stored hot water in a case when the hot water supply operation is started within a predetermined standby time after the stop of the hot water supply operation.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a hot water storage and hot water supply system in which hot water heated by a main heat source unit and stored is used for hot water supply. [Background technology]

[0002] Conventionally, hot water storage and hot water supply systems have been widely used in which hot water heated by, for example, a heat pump type heat source device as a main heat source device with high heating operation efficiency is stored in a hot water storage tank and the hot water in the hot water storage tank is used for hot water supply. The hot water discharged from the hot water storage tank is mixed with clean water in a hot water mixing section, and the hot water adjusted to the hot water supply setting temperature is supplied.

[0003] When there is no hot water in the hot water tank at a temperature that can supply the hot water supply temperature, an auxiliary heat source unit with a large heating capacity, such as a combustion type heat source unit, heats the hot water from the hot water tank and supplies hot water. In the heating operation by this auxiliary heat source unit, the heating capacity is adjusted to heat the hot water from the hot water tank to the hot water supply temperature.

[0004] When the hot water temperature in the hot water storage tank is lower than the hot water supply setting temperature but close to the hot water supply setting temperature, there is a risk that the temperature will be higher than the hot water supply setting temperature even if the auxiliary heat source unit is heated with its minimum heating capacity. Therefore, when heating with the auxiliary heat source unit, the hot water mixing section mixes clean water to lower the temperature below a specified temperature before allowing it to enter the auxiliary heat source unit, and the auxiliary heat source unit is operated to heat the water, adjusting it to the hot water supply setting temperature and supplying hot water.

[0005] After hot water supply accompanied by the heating operation of the auxiliary heat source unit is stopped, there are cases where a certain amount of high-temperature hot water is stored in the hot water tank by the main heat source unit until hot water supply is resumed. When hot water supply is resumed, if the hot water mixing section remains in the same state (mixing ratio) as in the previous hot water supply, the high-temperature hot water in the hot water storage tank may be supplied at a temperature higher than the hot water supply setting, or the hot water may be heated to a temperature higher than the hot water supply setting by the heating operation of the auxiliary heat source unit and supplied.

[0006] For this reason, for example, as in Patent Document 1, a technique is known in which, when hot water supply is resumed in a short time, the hot water tank side of the hot water mixing section is closed and the clean water side is opened to allow low-temperature hot water to enter the auxiliary heat source unit, and hot water is supplied after being adjusted to the hot water supply setting temperature by the heating operation of the auxiliary heat source unit.Also, as in Patent Document 2, a technique is known in which, when hot water supply is stopped, the hot water mixing section is adjusted to a predetermined mixing ratio during standby, and after hot water supply is resumed, adjustment of the mixing ratio begins only when the temperature of the hot water dispensed from the hot water mixing section reaches or exceeds a predetermined temperature. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 5379083 [Patent Document 2] Patent No. 4069853 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in Patent Document 1, when hot water supply is resumed in a short time, the temperature of the hot water entering the auxiliary heat source unit may be lower than the previous time of hot water supply, and it takes time for the heating operation of the auxiliary heat source unit to stably supply hot water at the set hot water supply temperature. Also, in Patent Document 2, the mixing ratio of the hot water mixing unit during standby is usually small on the hot water tank side and large on the clean water side to ensure safety, so like Patent Document 1, it takes time until hot water can be stably supplied at the set hot water supply temperature when hot water supply is resumed.

[0009] An object of the present invention is to provide a hot water storage and hot water supply system that can stably supply hot water at a hot water supply setting temperature after hot water supply is resumed. [Means for solving the problem]

[0010] The hot water storage and hot water supply system of the invention of claim 1 is a hot water storage and hot water supply system having a hot water storage unit with a hot water storage tank for storing hot water, and a heat source machine that performs a heating operation when the hot water discharged from the hot water storage unit is equal to or lower than a predetermined heating start temperature to supply hot water at a preset hot water supply setting temperature, the hot water storage unit includes a hot water mixing section that adjusts the temperature of the hot water in the hot water storage tank by mixing it with clean water and supplies it to the heat source machine, an outlet hot water temperature detection means that detects the outlet hot water temperature to the heat source machine, and a stored hot water heat amount detection means that detects the stored hot water heat amount in the hot water storage tank. , savings A hot water unit control section is provided. The hot water storage unit control unit, as a hot water discharging operation, When the stored hot water heat amount is equal to or greater than a preset reference heat amount, the hot water supply setting temperature is set as a target temperature. The hot and cold water mixing section Temperature control While the hot water is being poured When the stored hot water heat amount is less than the reference heat amount, the heating start temperature is set as the target temperature. The hot and cold water mixing section Temperature control The hot water is then controlled to flow out. In the hot water storage and hot water supply system, the hot water storage unit control unit stores the hot water outlet temperature detected by the hot water outlet temperature detection means when the hot water outlet operation is stopped, and when the hot water outlet operation is started within a preset waiting time after the hot water outlet operation is stopped, At that point The stored outlet hot water temperature is set as the target temperature, regardless of the stored hot water heat amount.

[0011] According to the above configuration, hot water that is adjusted to the hot water supply setting temperature by the hot water storage unit is supplied without being heated by the heat source unit, and hot water that is adjusted to the heating start temperature by the hot water storage unit as a target temperature is heated to the hot water supply setting temperature by the heat source unit and supplied. The hot water supply operation by this hot water storage unit adjusts the temperature of hot water to a target temperature that is set based on the amount of heat stored in the hot water storage tank. When the hot water supply operation is stopped, the adjusted hot water outlet temperature is stored, and if the hot water supply operation is resumed within the standby time, At that pointThe temperature is adjusted to the stored hot water outlet temperature regardless of the amount of heat stored in the hot water tank. Therefore, when the hot water supply operation is resumed during the standby time, hot water adjusted to the same outlet temperature as the previous hot water supply is supplied to the heat source unit, recreating the previous hot water supply situation, so that hot water can be stably supplied at the hot water supply setting temperature without being affected by the amount of heat stored. Therefore, even if high-temperature hot water is stored in the hot water tank during the standby time and the amount of heat stored changes, the risk of high-temperature hot water being supplied due to this high-temperature hot water can be prevented.

[0012] The hot water storage and hot water supply system of the invention of claim 2 is characterized in that, in the invention of claim 1, the hot water storage unit control unit maintains the state of the hot water mixing section at the time the hot water dispensing operation was stopped during standby after the hot water dispensing operation was stopped. According to the above configuration, the state of the hot water mixing section at the time when the hot water dispensing operation was stopped is maintained during standby after the hot water dispensing operation is stopped. Therefore, when the hot water dispensing operation is resumed during the standby time, the previous hot water supply state is reproduced, making it easier to adjust the hot water temperature to the previous hot water supply temperature.

[0013] The hot water storage and hot water supply system of the invention of claim 3 is characterized in that, in the invention described in claim 1, the hot water storage unit control unit sets the stored hot water outlet temperature as a target temperature when the heat source unit was performing heating operation when the hot water outlet operation was stopped and the hot water outlet operation is started within a predetermined waiting time after the hot water outlet operation was stopped. According to the above configuration, if the heat source unit was performing heating operation in the previous hot water supply and the hot water supply operation is started during the standby time, the stored hot water supply temperature is set as the target temperature. Therefore, even if high-temperature hot water is stored during standby, the hot water supply temperature from the previous hot water supply is set as the target temperature for temperature adjustment, and the stored high-temperature hot water is adjusted and supplied. Since the amount of heat stored during the standby time is not large, if the stored hot water is adjusted to the hot water supply setting temperature and supplied, the hot water will soon run out and switch to heating operation by the heat source unit, resulting in an unstable hot water supply temperature. However, by reproducing the hot water supply with the previous heating operation, it is possible to prevent the hot water supply temperature from becoming unstable. Effect of the Invention

[0014] According to the hot water storage and hot water supply system of the present invention, hot water can be stably supplied at the hot water supply setting temperature after hot water supply is resumed. [Brief description of the drawings]

[0015] [Figure 1] 1 is an explanatory diagram of the configuration of a hot water storage and supply system according to an embodiment of the present invention. [Diagram 2] 13 is a flowchart for controlling the hot water discharge operation of the hot water storage unit. [Diagram 3] 11 is a flowchart for setting a target temperature for hot water discharged from the hot water storage unit. [Figure 4] 4 is a heating operation control flowchart of the heat source unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the mode for carrying out the present invention will be described based on examples. EXAMPLES

[0017] First, the configuration of a hot water storage and supply system 1 of the present invention will be described with reference to FIG. The hot water storage and hot water supply system 1 has a hot water storage unit 3 equipped with a hot water storage tank 2, and, for example, a combustion-type heat source device 4. The hot water storage unit 3 has, for example, a heat pump-type heat source device as a main heat source device 5, and performs a hot water storage operation in which hot water heated to a predetermined hot water storage set temperature by the main heat source device 5 is stored in the hot water storage tank 2. The heat source device 4 is an auxiliary heat source device that performs a heating operation when the temperature of the hot water in the hot water storage tank 2 is not enough to supply hot water at the hot water supply set temperature. This heat source device 4 performs a heating operation or supplies hot water to the hot water tap 6 without performing a heating operation, depending on the temperature of the hot water dispensed from the hot water storage unit 3.

[0018] A main heat source unit supply passage 8 equipped with a pump 7 for supplying hot water from the hot water tank 2 to the main heat source unit 5 is connected to the bottom of the hot water storage tank 2. A main heat source unit return passage 9 for storing hot water heated by the main heat source unit 5 in the hot water storage tank 2 is connected to the top of the hot water storage tank 2. A changeover valve 10 for switching the hot water flow path is provided in the main heat source unit return passage 9, and a return branch passage 9a branched off from the main heat source unit return passage 9 by this changeover valve 10 is connected to a portion of the main heat source unit supply passage 8 upstream of the pump 7.

[0019] A return temperature sensor 9b that detects the temperature of the hot water heated by the main heat source unit 5 is disposed upstream of the switching valve 10 in the main heat source unit return passage 9. For example, if the temperature detected by the return temperature sensor 9b immediately after the main heat source unit 5 is started is lower than a predetermined hot water set temperature, the switching valve 10 is switched from the hot water tank 2 side to the return branch passage 9a side, and the hot water is circulated without being returned to the hot water tank 2 until it can be sufficiently heated.

[0020] A water supply passage 11 that supplies clean water, as indicated by an arrow CW, is connected to the bottom of the hot water storage tank 2. A hot water outlet passage 12 for discharging hot water from the hot water storage tank 2 from the hot water storage unit 3 is connected to the top of the hot water storage tank 2. A water supply branch passage 11a that branches off from the water supply passage 11 is connected to a mixing valve 14 (hot water mixing section) that is disposed in the hot water outlet passage 12. The mixing valve 14 mixes the hot water discharged from the hot water storage tank 2 with clean water and discharges the hot water. Instead of the mixing valve 14, the hot water mixing section may be configured by a flow rate adjustment valve that adjusts the flow rate on the hot water storage tank 2 side and a flow rate adjustment valve that adjusts the flow rate on the water supply branch passage 11a side.

[0021] A plurality of hot water temperature sensors 2a-2d are disposed in the hot water tank 2 in the vertical direction, and can detect the temperature and amount of hot water stored in the hot water tank 2. The plurality of hot water temperature sensors 2a-2d correspond to stored hot water heat amount detection means that detects the amount of stored hot water heat in the hot water tank 2.

[0022] A supply water temperature sensor 11b is disposed in the water supply passage 11 to detect the temperature (supply water temperature) of clean water supplied from the water supply passage 11. A hot water outlet passage 12 is disposed with a hot water outlet flow rate sensor 12a to detect the hot water outlet flow rate from the hot water storage unit 3, a hot water storage tank outlet temperature sensor 12b to detect the temperature of hot water discharged from the hot water storage tank 2 (hot water storage tank outlet temperature), and an outlet hot water temperature sensor 12c (outlet hot water temperature detection means) to detect the outlet hot water temperature from the hot water storage unit 3.

[0023] The hot water outlet passage 12 of the hot water storage unit 3 and the water supply port 4a of the heat source unit 4 are connected by a hot water passage 15. The hot water supply port 4b of the heat source unit 4 is connected to a hot water supply passage 16 which is connected to the hot water tap 6. The heat source unit 4 has an inlet water temperature sensor 4c which detects the inlet temperature of the hot water entering from the water supply port 4a, a hot water supply temperature sensor 4d which detects the hot water supply temperature of the hot water supplied from the hot water supply port 4b, and a hot water supply flow rate sensor 4e which detects the hot water supply flow rate. The hot water discharged from the hot water storage unit 3 is supplied to the hot water tap 6 via the heat source unit 4, and is supplied from the hot water tap 6 as shown by the arrow HW.

[0024] The hot water storage unit 3 has a hot water storage unit control unit 18 that drives the main heat source unit 5 and pump 7 to circulate hot water between the hot water storage tank 2 and the main heat source unit 5 and controls a hot water storage operation in which hot water heated by the main heat source unit 5 is stored from the upper part of the hot water storage tank 2. An operation terminal 19 is connected to the hot water storage unit control unit 18 and the heat source unit 4 to enable a user to set, for example, the hot water supply setting temperature, etc.

[0025] The hot water storage unit control unit 18 adjusts the mixing ratio in the mixing valve 14 to dispense hot water so that the temperature detected by the outlet hot water temperature sensor 12c becomes a preset hot water supply setting temperature or a predetermined heating start temperature based on the hot water storage tank outlet hot water temperature detected by the hot water storage tank outlet hot water temperature sensor 12b, the supply water temperature detected by the supply water temperature sensor 11b, and the hot water outlet flow rate detected by the outlet hot water flow rate sensor 12a. The hot water storage unit control unit 18 also acquires (calculates) the stored hot water heat quantity based on the detected temperatures of the hot water storage temperature sensors 2a-2d (storage hot water heat quantity detection means).

[0026] The hot water storage operation by the hot water storage unit control unit 18 is executed, for example, so that the hot water storage tank 2 is filled with hot water at the hot water storage set temperature at a set time. Also, when the stored hot water heat amount falls below the reference heat amount, the hot water storage operation may be executed so that the hot water storage tank 2 is filled with hot water at the hot water storage set temperature, or the hot water storage operation may be executed so that the required heat amount predicted based on the hot water supply usage learned and stored by the hot water storage unit control unit 18 is stored.

[0027] Next, the hot water supply operation control by the hot water storage unit control unit 18 in the hot water supply operation in which hot water adjusted in temperature by the hot water storage unit 3 is supplied to the heat source device 4 will be described with reference to the flowchart in Fig. 2. In the figure, Si (i = 1, 2, ...) represents a step.

[0028] When the hot water discharge operation control is started, in S1 it is determined whether or not the hot water discharge flow rate sensor 12a has detected the hot water discharge flow rate. This S1 is a step for determining the start of hot water discharge, and is configured to repeatedly perform the determination in S1 in order to detect the start of hot water discharge from the hot water storage unit 3 accompanying the start of hot water supply at the hot water tap 6. If the determination in S1 is No, the determination in S1 is performed again, and if the determination in S1 is Yes, the process proceeds to S2.

[0029] In S2, a target temperature for adjusting the temperature of the hot water to be dispensed at the start of the hot water dispensing operation is set, and the process proceeds to S3. As shown in FIG. 3, in S21, the target temperature setting at the start of the hot water dispensing operation is determined as to whether or not a predetermined standby time (for example, a short time of about 3 to 10 minutes) has elapsed since the previous hot water dispensing operation was stopped. If the determination in S21 is Yes due to the elapse of the standby time, the process proceeds to S22, and in S22, it is determined whether or not the stored hot water heat amount is equal to or greater than a predetermined reference heat amount. The reference heat amount is set in advance as a reference for operating the heat source unit 4. In order to prevent fluctuations in the hot water supply temperature due to insufficient heating when the hot water at the hot water storage temperature in the hot water storage tank 2 is used up and the heating operation is started, the heating start temperature is set as the target temperature when the temperature falls below the reference heat amount, and the heating operation is started. For example, the heat amount when hot water at the hot water supply setting temperature is stored up to the position of the topmost hot water storage temperature sensor 2d is set as the reference heat amount.

[0030] If the determination in S22 is Yes, the process proceeds to S23, where the hot water supply setting temperature is set as the target temperature for temperature adjustment and the process returns. If the determination in S22 is No, the process proceeds to S24, where the heating start temperature is set as the target temperature for temperature adjustment and the process returns. On the other hand, if the standby time has not elapsed and the determination in S21 is No, the process proceeds to S25, where the stored hot water outlet temperature of the previous hot water supply operation is set as the target temperature for temperature adjustment and the process returns. Therefore, after the standby time has elapsed, the target temperature is set based on the stored hot water heat amount, and if hot water supply is resumed in a short time before the standby time has elapsed, the stored hot water outlet temperature of the previous hot water supply operation is set as the target temperature, regardless of the stored hot water heat amount.

[0031] Next, in S3 of FIG. 2, it is determined whether the target temperature set in S2 is the hot water supply setting temperature. If the determination in S3 is Yes, the process proceeds to S4, where hot water adjusted to the target temperature (hot water supply setting temperature) is dispensed in S4, and the process proceeds to S5. Then, in S5, it is determined whether the stored hot water heat amount is equal to or greater than the reference heat amount, and if the determination in S5 is Yes, the process proceeds to S8. If the determination in S5 is No, the process proceeds to S6, where the target temperature is changed and set to the heating start temperature in S6, and the process proceeds to S8. On the other hand, if the determination in S3 is No, the process proceeds to S7, where hot water adjusted to the target temperature (heating start temperature or stored hot water outlet temperature) is dispensed in S7, and the process proceeds to S8. Note that if the hot water in the hot water storage tank 2 is at or below the target temperature, hot water at or below the target temperature is dispensed.

[0032] Next, in S8, it is determined whether the hot water outlet flow rate sensor 12a has detected no flow rate. This is the step for determining whether hot water outlet is stopped when hot water supply is stopped by closing the hot water tap 6. If the determination in S8 is No (hot water outlet continues), the process returns to S3. If the determination in S8 is Yes (hot water outlet is stopped), the process proceeds to S9, where the hot water outlet operation is stopped and the process proceeds to S10.

[0033] In S10, the outlet hot water temperature detected by outlet hot water temperature sensor 12c when the hot water outlet operation was stopped is stored, and the process proceeds to S11. Then, in S11, it is determined whether a predetermined standby time has elapsed.

[0034] If the determination in S11 is No, the process proceeds to S12, where the state (mixing ratio) of the mixing valve 14 at the time when the hot water dispensing operation was stopped is maintained, and the process proceeds to S13. Then, in S13, it is determined whether the hot water discharge flow rate sensor 12a has detected the hot water discharge flow rate, and if the determination in S13 is No, the process returns to S11, and if the determination in S13 is Yes, the process returns to S2. By maintaining the state (mixing ratio) of the mixing valve 14, when hot water supply is resumed within the standby time, the stored hot water discharge temperature can be set as the target temperature and hot water can be dispensed without adjusting the mixing ratio. Therefore, the previous hot water supply situation can be quickly reproduced, and hot water can be stably supplied at the hot water supply setting temperature.

[0035] On the other hand, if the determination in S11 is Yes, the process proceeds to S14, where the state (mixing ratio) of the mixing valve 14 is adjusted to the standby state and the process returns, and the hot water discharge operation control is started again from S1. The standby state of the mixing valve 14 is set to open the water supply branch passage 11a side widely in order to prevent high-temperature hot water from being discharged from the hot water storage unit 3 when high-temperature hot water is stored in the hot water storage tank 2 by hot water storage operation during standby. When hot water supply is resumed after the standby time has elapsed, a target temperature is set according to the amount of stored hot water heat, and the mixing ratio of the mixing valve 14 is adjusted to supply hot water. If the previous hot water supply was hot water supply using a heating operation by the heat source unit 4, the amount of stored hot water heat may have increased sufficiently by the hot water storage operation during standby, so an optimal hot water discharge operation can be performed by setting the target temperature according to the amount of stored hot water heat.

[0036] The heat source unit 4 supplies hot water whose temperature has been adjusted by the hot water discharge operation of the hot water storage unit 3 to the hot water tap 6. The heating operation control at this time will be described with reference to the flowchart of FIG. When the heating operation control is started, in S31, it is determined whether or not the hot water supply flow rate sensor 4e has detected the hot water supply flow rate. This S31 is a step for determining whether hot water supply has started, and is configured to repeatedly perform the determination in S31 when hot water is not being supplied so as to be able to detect the start of hot water supply at the hot water tap 6. If the determination in S31 is No, the determination in S31 is performed again, and if the determination in S31 is Yes, the process proceeds to S32.

[0037] In S32, it is determined whether the inlet water temperature detected by the inlet water temperature sensor 4c of the heat source unit 4 is higher than the heating start temperature. This is a step for determining whether to perform heating operation in the heat source unit 4. The heating start temperature may be set according to the hot water supply setting temperature so that hot water can be supplied at the hot water supply setting temperature when heating operation is performed with a heating capacity equal to or higher than the minimum heating capacity, for example, or a predetermined temperature may be set as the heating start temperature in advance.

[0038] If the determination in S32 is Yes, the process proceeds to S33, where hot water is supplied without performing a heating operation, and the process proceeds to S36. On the other hand, if the determination in S32 is No, the process proceeds to S34, where the amount of heat required to supply hot water at the set hot water supply temperature is calculated based on the inlet water temperature, hot water supply flow rate, and set hot water supply temperature, and the process proceeds to S35. Then, in S35, a heating operation is performed with the required amount of heat, hot water heated to the set hot water supply temperature is supplied, and the process proceeds to S36.

[0039] In S36, it is determined whether the hot water supply flow rate sensor 4e has detected no hot water supply flow rate. If the determination in S36 is No (hot water supply continues), the process returns to S32. If the determination in S36 is Yes (hot water supply ends), the process proceeds to S37, where hot water supply is stopped (heating operation is stopped if heating operation was being performed) and the process returns, and this heating operation control is started again from S31. Note that a heating control unit (not shown) of the heat source unit 4 may perform this heating operation control, or the hot water storage unit control unit 18 may be configured to perform the heating operation control of the heat source unit 4.

[0040] The operation and effects of the hot water storage and supply system 1 will be described. The hot water that is adjusted to the hot water supply setting temperature by the hot water storage unit 3 is supplied without being heated by the heat source unit 4. The hot water that is adjusted to the heating start temperature by the hot water storage unit 3 is supplied without being heated by the heat source unit 4. The hot water supply operation by the hot water storage unit 3 adjusts the temperature of the hot water to the target temperature set based on the amount of heat stored in the hot water storage tank 2. When the hot water supply operation is stopped, the adjusted hot water outlet temperature is stored, and if the hot water supply operation is resumed within the standby time, the temperature is adjusted to the stored hot water outlet temperature regardless of the amount of heat stored in the hot water storage tank 2.

[0041] Therefore, when the hot water supply operation is resumed during the standby time, hot water adjusted to the same hot water supply temperature as the previous hot water supply is supplied to the heat source unit 4, reproducing the previous hot water supply situation, so that hot water can be stably supplied at the hot water supply setting temperature without being affected by the amount of stored hot water heat. Therefore, even if high-temperature hot water is stored in the hot water storage tank 2 during the standby time and the amount of stored hot water heat changes, the risk of high-temperature hot water being supplied due to this high-temperature hot water can be prevented. Also, if the heat source unit 4 was performing heating operation during the previous hot water supply, the amount of stored hot water heat is not large during the standby time, so if the stored hot water is adjusted to the hot water supply setting temperature and supplied, the hot water runs out immediately and the operation switches to heating operation by the heat source unit 4, so the hot water supply temperature is not stable, but since the previous hot water supply situation is reproduced, it is possible to prevent the hot water supply temperature from becoming unstable.

[0042] During standby after the hot water supply operation is stopped, the state of the mixing valve 14 (hot water mixing section) at the time when the hot water supply operation was stopped is maintained. Therefore, if the hot water supply operation is resumed during the standby time, the previous hot water supply state is reproduced, making it easier to adjust the hot water supply temperature to the previous hot water supply temperature.

[0043] If the heat source unit 4 was performing heating operation in the previous hot water supply and the hot water supply operation is started during the standby time, the stored hot water supply temperature is set as the target temperature. Therefore, even if high-temperature hot water is stored during standby, the hot water supply temperature from the previous hot water supply is set as the target temperature for temperature adjustment, and the stored high-temperature hot water is adjusted in temperature and supplied. Since the amount of heat stored during the standby time is not large, if the stored hot water is adjusted to the hot water supply setting temperature and supplied, the hot water will soon run out and the system will switch to hot water supply by the heating operation of the heat source unit 4, resulting in an unstable hot water supply temperature. However, by reproducing hot water supply with the previous heating operation, it is possible to prevent the hot water supply temperature from becoming unstable.

[0044] In addition, a person skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment without departing from the spirit of the present invention, and the present invention includes such modifications. [Explanation of symbols]

[0045] 1: Hot water storage system 2: Hot water tank 2a to 2d: Hot water temperature sensor (hot water heat quantity detection means) 3: Hot water storage unit 4:Heat source machine (auxiliary heat source machine) 5: Main heat source machine 6: Hot water tap 7: Pump 8: Main heat source unit access passage 9: Main heat source return passage 9a: Return passage 10: Switching valve 11:Water supply passage 11a: Water supply branch passage 11b: Water supply temperature sensor 12: Hot water passage 12a: Flow rate sensor 12b: Hot water tank outlet temperature sensor 12c: Outlet water temperature sensor (outlet water temperature detection means) 14: Mixing valve (hot water mixing section) 15: Hot water passage 16: Hot water passage 18: Hot water storage unit control section 19: Operation terminal

Claims

1. A hot water storage and hot water supply system including a hot water storage unit having a hot water storage tank for storing hot water, and a heat source machine that performs a heating operation when the hot water discharged from the hot water storage unit is equal to or lower than a predetermined heating start temperature to supply hot water at a preset hot water supply temperature, The hot water storage unit includes a hot water mixing section that adjusts the temperature of the hot water in the hot water storage tank by mixing it with clean water and supplies the hot water to the heat source unit, a hot water outlet temperature detection means that detects the hot water outlet temperature to the heat source unit, a hot water storage heat amount detection means that detects the hot water storage heat amount in the hot water storage tank, and a hot water storage unit control section, and the hot water storage unit control section controls the hot water mixing section to adjust the temperature and supply hot water using the hot water supply setting temperature as a target temperature when the hot water storage heat amount is equal to or greater than a preset standard heat amount, and controls the hot water mixing section to adjust the temperature and supply hot water using the heating start temperature as a target temperature when the hot water storage heat amount is less than the standard heat amount, in a hot water storage hot water supply system, The hot water storage unit control unit stores the outlet hot water temperature detected by the outlet hot water temperature detection means when the hot water discharge operation is stopped, and when the hot water discharge operation is started within a predetermined waiting time after the hot water discharge operation is stopped, sets the stored outlet hot water temperature as the target temperature regardless of the stored hot water heat amount at that time.

2. The hot water storage and hot water supply system according to claim 1, characterized in that the hot water storage unit control unit maintains the state of the hot water mixing unit at the time when the hot water dispensing operation was stopped during standby after the hot water dispensing operation was stopped.

3. The hot water storage unit control unit of the hot water storage system described in claim 1 is characterized in that when the heat source unit was performing heating operation when the hot water discharging operation was stopped and the hot water discharging operation was started within a predetermined waiting time after the hot water discharging operation was stopped, the stored hot water discharging temperature is set as a target temperature.

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