Hot water storage and heating system

Abstract

To provide a hot water storage type water heater capable of determining presence / absence of abnormality of a mixing valve to prevent high-temperature hot water from coming out, and capable of determining the presence / absence of abnormality of the mixing valve without interfering with use of hot water supply.SOLUTION: A hot water storage type water heater (1) comprises a heat source machine (4), a hot water storage tank (2), a control unit (18) that controls hot water storage operation of storing hot water heated by the heat source machine (4) in the hot water storage tank (2), and a mixing valve (14) that mixes the hot water discharged from the hot water storage tank (2) with tap water to supply hot water. The control unit (18) is configured to check the operation of the mixing valve (14) before starting hot water storage when a target hot water storage temperature for the hot water storage operation is equal to or higher than a preset high temperature reference temperature.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a hot water storage and supply device that heats water with a heat source machine, stores the hot water in a hot water storage tank, and uses the hot water for hot water supply.

Background Art

[0002] Conventionally, a hot water storage and supply device that stores hot water heated by, for example, a hot water heating device that uses heat during power generation or a heat pump unit as a heat source machine in a hot water storage tank and uses the hot water in this hot water storage tank for hot water supply has been widely used. In addition to a heat source machine and a hot water storage unit including a hot water storage tank, this hot water storage and supply device often includes, for example, a combustion-type auxiliary heat source machine so that hot water supply can be performed even when there is no hot water at a temperature that allows hot water supply in the hot water storage tank.

[0003] Some hot water storage and supply devices are configured such that the hot water discharged from the hot water storage unit is supplied to a hot water supply faucet via an auxiliary heat source machine. When hot water supply starts by opening the hot water supply faucet in this hot water storage and supply device, high-temperature hot water discharged from the hot water storage tank and low-temperature make-up water are mixed by a mixing valve in the hot water storage unit, and the hot water with adjusted temperature is discharged from the hot water storage unit. Then, the hot water discharged from the hot water storage unit is supplied to the hot water supply faucet via the auxiliary heat source machine.

[0004] At this time, the auxiliary heat source machine heats or does not heat for hot water supply according to the temperature of the hot water discharged from the hot water storage unit. The heating operation of the auxiliary heat source machine is performed when there is no hot water at a temperature that allows hot water supply at the hot water supply set temperature in the hot water storage tank, and the hot water discharged from the hot water storage unit is heated to the hot water supply set temperature for hot water supply. On the other hand, when hot water adjusted to the hot water supply set temperature is discharged from the hot water storage unit, hot water supply is performed without heating.

[0005] During the heating operation of the auxiliary heat source unit, the heating capacity is adjusted to heat the hot water from the hot water storage unit to the set hot water temperature. However, if the temperature of the hot water in the hot water storage tank is below the set hot water temperature but close to it, there is a risk that the hot water supplied will be hotter than the set hot water temperature even when heated at the minimum heating capacity of the auxiliary heat source unit. Therefore, when heating with the auxiliary heat source unit, tap water is mixed in with the hot water using a mixing valve to lower the temperature to below a predetermined target hot water output temperature before the hot water is supplied from the hot water storage unit, and then the temperature is adjusted to the set hot water temperature by the heating operation of the auxiliary heat source unit.

[0006] Incidentally, if a malfunction occurs in the mixing valve of the hot water storage unit, where the hot water from the storage tank and tap water are mixed, there is a risk that hot water hotter than the set temperature may be dispensed from the storage unit. In this case, the auxiliary heat source unit will supply this hot water without heating it, posing a risk of burns to the user due to unexpectedly high-temperature hot water.

[0007] Therefore, the hot water storage unit is equipped with a bypass passage for supplying low-temperature tap water to the downstream side of the mixing valve, and a solenoid valve for opening and closing this bypass passage, as a means of avoiding the discharge of hot water at a temperature above a predetermined standard temperature, as in the hot water supply system of Patent Document 1, for example. When hot water at a temperature above a predetermined high-temperature standard temperature flows downstream of the mixing valve, the solenoid valve is opened, allowing low-temperature tap water to mix with the hot water from the bypass passage, and hot water with a significantly lower temperature is discharged. Patent Document 1 describes a technique that allows for easy fault diagnosis of the mixing valve and the solenoid valve of the bypass passage during maintenance.

[0008] Furthermore, as shown in Patent Document 2, for example, there is a known technique for determining whether or not there is a malfunction in the solenoid valve of the bypass passage. Moreover, as shown in Patent Document 3, when a malfunction occurs in the mixing valve during hot water supply and the hot water temperature becomes abnormal, there is a known method for opening the bypass valve that opens and closes the bypass passage and fully opening the mixing valve on the hot water side to determine if there is a malfunction in the mixing valve and the bypass valve. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 4003682 [Patent Document 2] Japanese Patent Publication No. 2014-190634 [Patent Document 3] Patent No. 6623834 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] In the above-mentioned Patent Documents 1 and 2, the hot and cold water mixing valve or the high-temperature water outlet avoidance valve is activated while hot water is being dispensed, and fault diagnosis is performed based on the change in the dispensed water temperature. Therefore, the use of hot water is interrupted during the fault diagnosis. Furthermore, in Patent Document 3, the presence or absence of abnormalities in the mixing valve and bypass valve is determined when the dispensed water is hotter than the set temperature, so it is not possible to prevent high-temperature water from being dispensed in advance.

[0011] Therefore, the present invention aims to provide a hot water storage and supply system that can detect abnormalities in the mixing valve and prevent the discharge of high-temperature hot water in advance, while also detecting abnormalities in the mixing valve without interfering with the use of hot water. [Means for solving the problem]

[0012] The hot water storage device according to claim 1 comprises a heat source unit, a hot water storage tank, a control unit that controls a hot water storage operation for storing hot water heated by the heat source unit in the hot water storage tank, and a mixing valve that mixes the hot water dispensed from the hot water storage tank with tap water for supply, wherein the control unit checks the operation of the mixing valve before starting the hot water storage operation if the target hot water storage temperature for the hot water storage operation is equal to or higher than a preset high-temperature reference temperature.

[0013] According to the above configuration, in a hot water supply system that mixes hot water stored in a hot water storage tank with tap water using a mixing valve for hot water supply, when performing a hot water storage operation to achieve a target storage temperature above the high-temperature standard temperature, the operation of the mixing valve is checked before the hot water storage operation is performed. Therefore, if an abnormality is detected during the operation check of the mixing valve, the hot water supply can be easily avoided because hot water above the high-temperature standard temperature has not yet been stored in the hot water storage tank. Also, since the abnormality of the mixing valve can be detected before hot water storage, it does not interfere with the use of hot water.

[0014] The hot water storage and supply device of the invention of claim 2 is characterized in that, in the invention of claim 1, the control unit prohibits the storage of hot water at a target storage temperature above the high-temperature reference temperature if an abnormality is detected during the operation check of the mixing valve. With the above configuration, if an abnormality in the mixing valve is detected, hot water storage operation at a target storage temperature above the high-temperature standard temperature is prohibited. Therefore, high-temperature hot water is not stored in the storage tank, and high-temperature hot water output can be prevented in advance.

[0015] The hot water storage and supply device of the invention of claim 3 is characterized in that, in the invention of claim 1, if an abnormality is detected in the operation check of the mixing valve, the control unit changes the target hot water storage temperature for the hot water storage operation to a temperature below the high-temperature reference temperature and stores the hot water. With the above configuration, if an abnormality in the mixing valve is detected, the target hot water storage temperature, which is above the high-temperature standard temperature, is changed to below the high-temperature standard temperature, and hot water storage operation is performed. Therefore, it is possible to use the hot water stored in the storage tank for hot water supply while preventing the discharge of hot water above the high-temperature standard temperature.

[0016] The hot water supply device according to claim 4 is characterized in that, in the invention of any one of claims 1 to 3, the control unit, when a hot water supply request is made while the operation of the mixing valve is being checked, stops the operation check and controls the mixing by the mixing valve to supply hot water if there is hot water at a temperature that can be supplied in the hot water storage tank, and continues the operation check if there is no hot water at a temperature that can be supplied in the hot water storage tank. According to the above configuration, when there is a hot water supply request during the operation check of the mixing valve, if there is hot water at a temperature that can be used for hot water supply in the hot water storage tank, assuming there was no abnormality during the previous operation check of the mixing valve, the hot water supply request is prioritized and the operation check is aborted, so the use of hot water supply is not hindered. On the other hand, when there is a hot water supply request during the operation check of the mixing valve, if there is no hot water at a temperature that can be used for hot water supply in the hot water storage tank, cold hot water is discharged for hot water supply regardless of the mixing ratio of the mixing valve. Therefore, the operation check of the mixing valve can be continued, and the abnormality of the mixing valve can be detected without hindering the use of hot water supply.

Effect of the Invention

[0017] According to the hot water storage and supply device of the present invention, it is possible to detect an abnormality of the mixing valve and prevent high-temperature hot water discharge in advance, and it is also possible to detect an abnormality of the mixing valve without hindering the use of hot water supply.

Brief Description of the Drawings

[0018] [Figure 1] It is an explanatory diagram of a hot water storage and supply device according to an embodiment of the present invention. [Figure 2] It is a flowchart of hot water storage operation control. [Figure 3] It is a flowchart showing an example of the operation when an abnormality occurs in the mixing valve. [Figure 4] It is a flowchart showing another example of the operation when an abnormality occurs in the mixing valve.

Modes for Carrying Out the Invention

[0019] Hereinafter, modes for carrying out the present invention will be described based on examples.

Examples

[0020] First, the configuration of the hot water storage and supply device 1 of the present invention will be described. As shown in Figure 1, the hot water storage and heating system 1 includes a hot water storage unit 3 equipped with a hot water storage tank 2, a heat pump unit 4 as a heat source, and, for example, a combustion-type auxiliary heat source unit 5. This hot water storage and heating system 1 performs a hot water storage operation in which hot water heated to a predetermined target storage temperature by the heat pump unit 4 is stored in the hot water storage tank 2. The auxiliary heat source unit 5, as indicated by the arrow HW, heats the hot water dispensed from the hot water storage unit 3 according to its temperature, or supplies it to the hot water tap 6 without heating, in order to supply hot water at the set hot water temperature from the tap 6.

[0021] Next, I will explain the hot water storage unit 3. At the bottom of the hot water storage tank 2, a supply passage 8 equipped with a hot water storage pump 7 is connected to supply hot water from the hot water storage tank 2 to the heat pump unit 4. At the top of the hot water storage tank 2, a return passage 9 is connected to store the hot water heated by the heat pump unit 4 in the hot water storage tank 2. A switching valve 10 is installed in the middle of the return passage 9 to switch the flow path of the hot water, and a return branch passage 9a, which branches off from the return passage 9 at this switching valve 10, is connected to the upstream portion of the supply passage 8 above the hot water storage pump 7.

[0022] Upstream of the switching valve 10 in the return passage 9, a return temperature sensor 9b is installed to detect the temperature of the hot water heated by the heat pump unit 4. For example, if the temperature detected by the return temperature sensor 9b immediately after the heat pump unit 4 is started is lower than a predetermined hot water storage setting temperature, the switching valve 10 can be switched from the hot water storage tank 2 side to the return branch passage 9a side, allowing the hot water to be circulated without being returned to the hot water storage tank 2 until it can be sufficiently heated.

[0023] A water supply passage 11, indicated by arrow CW, is connected to the bottom of the hot water storage tank 2 to supply tap water. A hot water outlet passage 12 is connected to the top of the hot water storage tank 2 to dispense hot water from the hot water storage unit 3 to the hot water storage tank 2. A mixing valve 14 is located in the middle of the hot water outlet passage 12, and a water supply branch passage 11a, which branches off from the middle of the water supply passage 11, is connected to the mixing valve 14. The hot water from the hot water storage tank 2 and the tap water from the water supply branch passage 11a are mixed in the mixing valve 14 and dispensed from the hot water storage unit 3. The opening of the mixing valve 14 is linked so that it increases the opening on the hot water side of the hot water storage tank 2 and decreases the opening on the tap water side of the water supply branch passage 11a.

[0024] Multiple hot water temperature sensors 2a to 2d are installed in the hot water storage tank 2 at predetermined intervals in the vertical direction, allowing for the detection of the temperature of the hot water stored in the tank and the amount of hot water at that temperature. Furthermore, to prevent the stored hot water from cooling down, an insulating material (not shown) is installed to cover these hot water temperature sensors 2a to 2d and the hot water storage tank 2.

[0025] The water supply passage 11 is equipped with a water supply temperature sensor 11b that detects the temperature of the tap water (water supply temperature) flowing through the water supply passage 11. The hot water outlet passage 12 is equipped with a hot water flow rate sensor 12a that detects the flow rate of hot water from the hot water storage unit 3, a hot water storage tank outlet temperature sensor 12b that detects the temperature of the hot water supplied from the hot water storage tank 2 to the mixing valve 14, and a hot water outlet temperature sensor 12c that detects the temperature of the hot water from the hot water storage unit 3. The hot water outlet passage 12 is connected to the water inlet 5a of the auxiliary heat source unit 5 by a hot water passage 15, and the hot water outlet 5b of the auxiliary heat source unit 5 is connected to the hot water tap 6 by a hot water passage 16.

[0026] The hot water storage unit 3 has a hot water storage unit control unit 18 (control unit) that performs, for example, control of the hot water storage operation and control of the temperature adjustment of the hot water dispensed from the hot water storage unit 3. The hot water storage unit control unit 18 drives the heat pump unit 4 and the hot water storage pump 7 to perform a hot water storage operation in which hot water heated by the heat pump unit 4 is stored from the top of the hot water storage tank 2. In addition, when the hot water outlet flow rate sensor 12a detects a flow rate of more than a predetermined flow rate, the mixing ratio of the mixing valve 14 is adjusted so that the temperature detected by the hot water outlet temperature sensor 12c becomes a predetermined hot water outlet temperature, based on the temperatures detected by the water supply temperature sensor 11b and the hot water storage tank outlet temperature sensor 12b, and then hot water is dispensed.

[0027] An operating terminal 19 is connected to the hot water storage unit control unit 18 and the auxiliary heat source unit 5, for example, for the user to set the hot water supply temperature. Multiple operating terminals 19 may be connected, and an operating terminal 19 corresponding to the hot water storage unit 3 may be connected to the hot water storage unit control unit 18, and an operating terminal corresponding to the auxiliary heat source unit 5 may be connected to the auxiliary heat source unit 5. Although not shown in the figures, the operating terminal 19 is equipped with a display unit for operating information, an operating unit, and an audio output unit.

[0028] Next, I will explain the hot water storage operation. The hot water storage unit control unit 18 learns and stores the time and amount of hot water usage as a hot water usage history, and predicts the start time and amount of hot water usage for future hot water use based on this history. Then, it performs a hot water storage operation to store the required amount of heat corresponding to the predicted amount of usage by the predicted start time of hot water use. The control of this hot water storage operation will be explained based on the flowchart in Figure 2. In the figure, Si (i=1,2,...) represents a step.

[0029] When hot water storage operation control starts, in S1 the target hot water storage temperature and storage amount are set based on the predicted hot water usage to store the required amount of heat, and then the process proceeds to S2. The target hot water storage temperature is set to be higher than the hot water supply set temperature and as low as possible within the range where the required amount of heat can be stored, in order to improve the operating efficiency of the heat pump unit 4. Since the capacity of the hot water storage tank 2 is limited, the higher the required amount of heat, the higher the target hot water storage temperature is set. In addition, although the hot water stored in the hot water storage tank 2 is often used up before the next hot water storage operation, if there is hot water remaining at a temperature that can be used for hot water supply, the required amount of heat can be stored by combining the heat of the remaining hot water.

[0030] In S2, it is determined whether the target hot water storage temperature is below a preset high-temperature reference temperature. The high-temperature reference temperature is a temperature at which there is no risk of burns even if the user touches it for a short time, and is set to, for example, 50°C. If the determination in S2 is Yes, the process proceeds to S3, where hot water storage to the target temperature begins and the process proceeds to S4. Next, in S4, it is determined whether the set amount of hot water storage has been reached. If the determination in S4 is No, hot water storage continues and the process returns to S4; if the determination in S4 is Yes, the process proceeds to S5. Finally, in S5, hot water storage ends and the hot water storage operation control is terminated.

[0031] On the other hand, if the result of S2 is No (the target hot water storage temperature is above the high-temperature standard temperature), the process proceeds to S6, where it is determined whether the hot water storage unit 3 is currently dispensing hot water. If the result of S6 is Yes, the process proceeds to S7, where it is determined whether there is hot water in the hot water storage tank 2 that can be used for hot water supply. If the result of S7 is Yes, the process proceeds to S8, where it is determined whether there is any abnormality in the temperature of the hot water currently being dispensed by the hot water storage unit 3. If the result of S8 is Yes, there is no abnormality in the mixing valve 14, so the hot water storage operation control is terminated after storing the set amount of hot water at the target hot water storage temperature set as described above. If the result of S8 is No, there is an abnormality in the mixing valve 14, so the process proceeds to S17 for the mixing valve abnormality operation described later.

[0032] On the other hand, if the judgment in S6 is No, or if the judgment in S7 is No, the process proceeds to S9. In S9, the operation check of the mixing valve 14 is started, and the process proceeds to S10. The operation check is performed by returning the mixing valve 14 to its home position, for example, with the fully open position of the water side as the home position, and confirming that it has returned to the home position. If the valve is already in the home position when the operation check starts, it is driven to close the water side and open the hot water storage tank side before returning to the home position. If there is no hot water at a temperature suitable for hot water supply in the hot water storage tank 2, low-temperature hot water is heated by the auxiliary heat source unit 5 and supplied as hot water, so even if the operation check is performed, low-temperature hot water is supplied to the auxiliary heat source unit 5, and hot water supply is not hindered.

[0033] Next, in S10, it is determined whether there is a request for hot water to be supplied to the hot water storage unit 3 while the operation of the mixing valve 14 is being checked. If the determination in S10 is Yes, the process proceeds to S11, where it is determined whether there is hot water in the hot water storage tank 2 at a temperature suitable for hot water supply.

[0034] If the determination in S11 is Yes, the process proceeds to S12. In S12, the hot water supply request is prioritized, the operation check of the mixing valve 14 is stopped, the water is mixed in the mixing valve 14 to reach the set hot water temperature, and the process proceeds to S13. In S13, it is determined whether there is an abnormality in the hot water temperature of the hot water storage unit 3 compared to the set hot water supply temperature. If the determination in S13 is No, there is no abnormality in the mixing valve 14, so the process proceeds to S3, and the hot water storage operation control is terminated after storing the set amount of hot water at the set target hot water temperature as explained earlier. If the determination in S13 is Yes, an abnormality in the mixing valve 14 has been detected, so the process proceeds to S17.

[0035] If the result of S11 is No, proceed to S14, where the operation of the mixing valve 14 is checked while hot water is dispensed and proceed to S15. Since there is no hot water at a temperature suitable for hot water supply in the hot water storage tank 2, the auxiliary heat source unit 5 heats the water for supply, so even if the operation is checked, low-temperature hot water is supplied to the auxiliary heat source unit 5, and hot water supply is not hindered. Also, if the result of S10 is No, proceed to S15.

[0036] Next, in S15, it is determined whether the operation check of the mixing valve 14 has been completed. If the determination in S15 is No, the process returns to S10. If the determination in S15 is Yes, the process proceeds to S16, where it is determined whether there is an abnormality in the mixing valve 14. For example, if the system fails to return to the home position or if the home position is clearly abnormal relative to the drivable range, it is determined that there is an abnormality in the mixing valve 14 (abnormality detection). If the determination in S16 is No, there is no abnormality in the mixing valve 14, so the process proceeds to S3, and the system stores the set amount of hot water at the set target hot water temperature as explained earlier, and the hot water storage operation control is terminated.

[0037] If there is a malfunction in the mixing valve 14 and the result of S16 is Yes, the result of S13 is Yes, or the result of S8 is No, the process proceeds to S17, where the mixing valve malfunction operation is executed. This mixing valve malfunction operation prohibits the storage of hot water at a target storage temperature above the high-temperature standard temperature in order to avoid high-temperature hot water output. Alternatively, the target storage temperature above the high-temperature standard temperature can be changed to a target storage temperature below the high-temperature standard temperature for storage. The user may operate the operation terminal 19 to select one of these options.

[0038] If the storage of hot water at a target storage temperature above the high-temperature standard temperature is prohibited, as shown in Figure 3, in S21, the user is notified of the malfunction of the mixing valve 14 from the operation terminal 19, for example by display or voice, and the process proceeds to S22. Then, in S22, the storage of hot water at a target storage temperature above the high-temperature standard temperature is prohibited, and the process returns, ending the hot water storage operation control. If the next hot water storage opportunity arises while the storage of hot water at a target storage temperature above the high-temperature standard temperature is prohibited, the operation of the mixing valve 14 may be omitted, and the hot water storage operation may be performed only if the target storage temperature is below the high-temperature standard temperature.

[0039] When changing the target hot water storage temperature to below the high-temperature standard temperature and storing hot water, as shown in Figure 4, in S31, the user is notified of the malfunction of the mixing valve 14 from the operation terminal 19, for example by display or voice, and the process proceeds to S32. Next, in S32, the set target hot water storage temperature is changed to below the high-temperature standard temperature and the process proceeds to S33. Then, in S33, the set amount of hot water stored is changed to the amount of hot water stored corresponding to the changed target hot water storage temperature and the process proceeds to S34.

[0040] Next, in S34, the system starts storing hot water at the changed target storage temperature and proceeds to S35, where it is determined whether the changed storage volume has been reached. If the determination in S35 is No, the system continues storing hot water and returns to S35. If the determination in S35 is Yes, the system proceeds to S36, where it finishes storing hot water and returns, ending the hot water storage operation control. If the malfunction of the mixing valve 14 has not been resolved and the next opportunity to store hot water arises, the system may, without checking the operation of the mixing valve 14, continue storing hot water if the target storage temperature is below the high-temperature standard temperature, or change the target storage temperature to below the high-temperature standard temperature and then store hot water.

[0041] The operation and effects of the above-described hot water storage and supply system 1 will be explained. The hot water storage and supply system 1, which mixes hot water stored in the hot water storage tank 2 with tap water using a mixing valve 14 for hot water supply, checks the operation of the mixing valve 14 before starting hot water storage when performing hot water storage operation to a target storage temperature above the high-temperature standard temperature. Therefore, even if an abnormality in the mixing valve 14 is detected, it can be easily avoided by preventing the discharge of hot water at a high temperature because the hot water above the high-temperature standard temperature has not yet been stored in the hot water storage tank 2. Also, because it is detected before hot water storage, the abnormality in the mixing valve 14 can be detected without interfering with the use of hot water.

[0042] If an abnormality in the mixing valve 14 is detected and hot water storage operation at a target temperature above the high-temperature standard temperature is prohibited, hot water at a temperature above the high-temperature standard temperature that poses a risk of burns will not be stored in the hot water storage tank 2, thus preventing high-temperature hot water from being dispensed in advance.

[0043] If an abnormality in the mixing valve 14 is detected and the target temperature is changed from above the high-temperature standard temperature to below the high-temperature standard temperature for hot water storage operation, hot water at temperatures above the high-temperature standard temperature that pose a risk of burns will not be stored in the hot water storage tank 2. Therefore, while preventing the discharge of hot water at high temperatures, hot water below the high-temperature standard temperature can be stored in the hot water storage tank 2 and used for hot water supply, thereby suppressing an increase in the opportunities for the auxiliary heat source unit 5 to heat up.

[0044] If a hot water supply request is made while the mixing valve 14 is being checked, and there is hot water at a suitable temperature in the hot water storage tank 2, the hot water supply request will take priority and the check will be stopped, assuming that there was no abnormality during the previous check of the mixing valve 14. Therefore, the use of hot water will not be interrupted. On the other hand, if a hot water supply request is made while the mixing valve 14 is being checked, and there is no hot water at a suitable temperature in the hot water storage tank 2, low-temperature hot water will be dispensed for hot water supply regardless of the mixing ratio of the mixing valve 14, and the check of the mixing valve 14 will continue. Therefore, the operation of the mixing valve 14 can be checked without interrupting the use of hot water, and any abnormalities in the mixing valve 14 can be detected.

[0045] The operation of the mixing valve 14 may be checked not only during hot water storage operation, but also once a day, for example at night when hot water is not being used, in order to detect any abnormalities in the mixing valve 14 in advance. In a hot water storage system equipped with a water heating device that utilizes heat generated during power generation instead of a heat pump unit 4 as a heat source, it is possible to configure the system to detect abnormalities by checking the operation of the mixing valve 14 as described above and prevent the output of high-temperature hot water. 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 present invention, and the present invention encompasses such modifications. [Explanation of symbols]

[0046] 1: Hot water storage and supply system 2: Hot water storage tank 2a~2d: Hot water storage temperature sensor 3: Hot water storage unit 4: Heat pump unit (heat source unit) 5:Auxiliary heat source machine 5a: Water inlet 5b: Hot water outlet 6: Hot water tap 7: Hot water storage pump 8: Outbound passage 9: Return passage 9a: Return branch passage 10: Switching valve 11:Water supply passage 11a: Water supply branching passage 11b: Water supply temperature sensor 12: Hot spring access passage 12a: Hot water flow sensor 12b: Hot water storage tank outlet temperature sensor 12c: Hot water temperature sensor 14: Mixing valve 15,16: Hot water passage 18: Hot water storage unit control unit (control unit) 19: Operating terminal

Claims

1. A hot water supply and storage device comprising a heat source unit, a hot water storage tank, a control unit for controlling the hot water storage operation for storing hot water heated by the heat source unit in the hot water storage tank, and a mixing valve for mixing the hot water dispensed from the hot water storage tank with tap water and supplying hot water, The hot water storage and supply device is characterized in that, when the target hot water storage temperature for the hot water storage operation is equal to or higher than a preset high-temperature reference temperature, the control unit checks the operation of the mixing valve before starting the hot water storage operation.

2. The hot water storage and supply device according to claim 1, characterized in that if an abnormality is detected during the operation check of the mixing valve, the control unit prohibits the storage of hot water at a target storage temperature equal to or higher than the high-temperature reference temperature.

3. The hot water storage and supply device according to claim 1, characterized in that if an abnormality is detected during the operation check of the mixing valve, the control unit changes the target hot water storage temperature for the hot water storage operation to a temperature below the high-temperature reference temperature and stores the hot water.

4. The hot water supply device according to any one of claims 1 to 3, characterized in that when a hot water supply request is made while the operation of the mixing valve is being checked, the control unit stops the operation check and controls the mixing by the mixing valve to supply hot water if there is hot water at a temperature that can be supplied in the hot water storage tank, and continues the operation check if there is no hot water at a temperature that can be supplied in the hot water storage tank.

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