JP2024061162A - Hot water storage and heating equipment - Google Patents

Abstract

[Problem] To provide a hot water storage and water supply device capable of determining the presence or absence of an abnormality in a mixing valve to prevent high-temperature hot water from being dispensed in advance, and capable of determining the presence or absence of an abnormality in the mixing valve without interfering with hot water supply use. [Solution] In a hot water storage and water supply device (1) having a heat source unit (4), a hot water storage tank (2), a control unit (18) that controls a hot water storage operation in which hot water heated by the heat source unit (4) is stored in the hot water storage tank (2), and a mixing valve (14) that mixes the hot water dispensed 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 the target hot water storage temperature for the hot water storage operation is equal to or higher than a preset high-temperature reference temperature. [Selected Figure] Figure 2

Description

The present invention relates to a hot water storage and hot water supply device that uses hot water heated by a heat source unit and stored in a hot water storage tank to supply hot water.

Conventionally, hot water storage and hot water supply systems have been widely used, which store hot water heated by a hot water heating device or heat pump unit that utilizes heat generated during power generation as a heat source unit in a hot water storage tank and use the hot water in the hot water storage tank to supply hot water. In addition to the heat source unit and the hot water storage unit equipped with the hot water storage tank, these hot water storage and hot water supply systems often include an auxiliary heat source unit, for example a combustion type, so that hot water can be supplied even if the hot water storage tank does not contain hot water at a temperature that can be used for hot water supply.

Some hot water storage and water supply devices are configured so that hot water discharged from the hot water storage unit is supplied to the hot water tap via an auxiliary heat source unit. When the hot water tap is opened to start using hot water, the high-temperature hot water discharged from the hot water storage tank and the low-temperature clean water are mixed in the mixing valve of the hot water storage unit, and the hot water with the adjusted temperature is discharged from the hot water storage unit. The hot water discharged from the hot water storage unit is then supplied to the hot water tap via the auxiliary heat source unit.

At this time, the auxiliary heat source unit supplies hot water, either heated or unheated, depending on the temperature of the hot water dispensed from the hot water storage unit. The heating operation of the auxiliary heat source unit is performed when there is no hot water in the hot water storage tank at a temperature that can be supplied at the hot water supply setting temperature, and the hot water dispensed from the hot water storage unit is heated to the hot water supply setting temperature and supplied. On the other hand, when hot water adjusted to the hot water supply setting temperature is dispensed from the hot water storage unit, the hot water is supplied unheated.

During 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 hot water supply set temperature. However, if the temperature of the hot water in the hot water storage tank is lower than the hot water supply set temperature but close to the hot water supply set temperature, there is a risk that the hot water supplied will be hotter than the hot water supply set temperature even when heated with the minimum heating capacity of the auxiliary heat source unit. Therefore, when heating with the auxiliary heat source unit, the hot water is mixed with clean water using a mixing valve to lower the temperature below a specified target hot water outlet temperature, and then discharged from the hot water storage unit, and the hot water is adjusted to the hot water supply set temperature by heating operation of the auxiliary heat source unit and supplied.

However, if a problem occurs with the mixing valve of the hot water storage unit in mixing the hot water from the hot water storage tank and tap water, there is a risk that the hot water storage unit will dispense hot water at a temperature higher than the set hot water temperature. In this case, the auxiliary heat source unit will dispense this high-temperature water without heating it, and there is a risk of the user being burned by the unexpected supply of high-temperature hot water.

Therefore, as a means of avoiding the discharge of hot water at a temperature higher than a preset specified temperature, the hot water storage unit is equipped with a bypass passage for bypassing the mixing valve to supply low-temperature clean water downstream of the mixing valve, and a solenoid valve for opening and closing this bypass passage, as in the hot water supply system of Patent Document 1, for example. When hot water at a temperature higher than a specified high-temperature reference temperature flows downstream of the mixing valve, the solenoid valve is opened to mix the low-temperature clean water with the high-temperature hot water from the bypass passage, and hot water with a significantly reduced temperature is discharged. Patent Document 1 describes a technology that makes it easy to diagnose faults in the mixing valve and the solenoid valve in the bypass passage during maintenance.

For example, a technique is known for determining whether or not there is a malfunction in the solenoid valve of the bypass passage, as in Patent Document 2. Furthermore, as in Patent Document 3, when a malfunction occurs in the mixing valve during hot water supply and the hot water outlet temperature becomes abnormal, a technique is known in which the bypass valve that opens and closes the bypass passage is opened and the mixing valve is fully opened on the hot water side to determine whether there is an abnormality in the mixing valve and the bypass valve.

Japanese Patent No. 4003682 JP 2014-190634 A Patent No. 6623834

In the above Patent Documents 1 and 2, the hot and cold water mixing valve or high-temperature hot water outlet avoidance valve is operated while hot water is being discharged, and a fault diagnosis is performed based on the change in the temperature of the hot water being discharged, so hot water supply is prevented from being used during the fault diagnosis. In addition, in Patent Document 3, the presence or absence of an abnormality in the mixing valve and bypass valve is determined when hot water is being discharged at a temperature higher than the set temperature, so the discharge of hot water cannot be prevented in advance.

The present invention aims to provide a hot water storage and hot water supply device that can detect an abnormality in the mixing valve and prevent high-temperature hot water from being discharged in advance, and that can detect an abnormality in the mixing valve without interfering with the use of hot water.

The hot water storage and hot water supply device of the invention of claim 1 has a heat source unit, a hot water storage tank, a control unit that controls a hot water storage operation in which hot water heated by the heat source unit is stored in the hot water storage tank, and a mixing valve that mixes the hot water discharged from the hot water storage tank with tap water to supply hot water, and is characterized in that, when the target hot water storage temperature of 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 hot water storage in the hot water storage operation.

According to the above configuration, in a hot water storage and hot water supply device that uses a mixing valve to mix high-temperature hot water stored in a hot water storage tank with clean water to supply hot water, when performing hot water storage operation at a target hot water storage temperature above the high-temperature reference temperature, the operation of the mixing valve is checked before the hot water storage operation is performed. Therefore, if an abnormality is detected when the operation of the mixing valve is checked, hot water above the high-temperature reference temperature has not yet been stored in the hot water storage tank, so high-temperature hot water can be easily avoided from being discharged. In addition, because it is before hot water is stored, an abnormality in the mixing valve can be detected without interfering with hot water supply.

The hot water storage and hot water 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 hot water storage temperature higher than the high temperature reference temperature when an abnormality is detected in checking the operation of the mixing valve.
According to the above configuration, when an abnormality is detected in the mixing valve, hot water storage operation at a target hot water storage temperature equal to or higher than the high temperature reference temperature is prohibited. Therefore, high-temperature hot water is not stored in the hot water storage tank, and high-temperature hot water can be prevented from being discharged in advance.

The hot water storage and hot water supply device of the invention of claim 3 is characterized in that, in the invention of claim 1, when an abnormality is detected in checking the operation of the mixing valve, the control unit changes the target hot water storage temperature for the hot water storage operation to a temperature lower than the high temperature reference temperature and stores hot water.
According to the above configuration, when an abnormality in the mixing valve is detected, the target hot water storage temperature that is equal to or higher than the high temperature reference temperature is changed to a temperature lower than the high temperature reference temperature and hot water storage operation is performed. Therefore, hot water stored in the hot water storage tank can be used for hot water supply while preventing hot water at a temperature higher than the high temperature reference temperature from being discharged.

The hot water storage and hot water supply device of the invention of claim 4 is characterized in that, in the invention of any one of claims 1 to 3, when a hot water supply request is made during operation check of the mixing valve, if there is hot water in the hot water storage tank at a temperature that can be used for hot water supply, the control unit stops the operation check and controls the mixing by the mixing valve to supply hot water, and continues the operation check if there is no hot water in the hot water storage tank at a temperature that can be used for hot water supply.
According to the above configuration, if there is a hot water supply request during a mixing valve operation check and there is hot water in the hot water storage tank at a temperature that can be used for hot water supply, it is assumed that there was no abnormality during the previous mixing valve operation check, and the hot water supply request is prioritized and the operation check is stopped, so that hot water use is not hindered. On the other hand, if there is a hot water supply request during a mixing valve operation check and there is no hot water in the hot water storage tank at a temperature that can be used for hot water supply, low-temperature hot water is discharged for hot water supply regardless of the mixing ratio of the mixing valve, so that the mixing valve operation check continues and an abnormality in the mixing valve can be detected without hindering hot water use.

The hot water storage and hot water supply device of the present invention can detect an abnormality in the mixing valve to prevent high-temperature hot water from being discharged in advance, and can detect an abnormality in the mixing valve without interfering with the use of hot water supply.

1 is an explanatory diagram of a hot water storage and heating device according to an embodiment of the present invention. 4 is a flowchart of hot water storage operation control. 5 is a flowchart showing an example of an operation when an abnormality occurs in the mixing valve. 10 is a flowchart showing another example of the operation when an abnormality occurs in the mixing valve.

The following describes the form for implementing the present invention based on examples.

First, the configuration of the hot water storage and supplying apparatus 1 of the present invention will be described.
As shown in Fig. 1, the hot water storage and hot water supply device 1 has a hot water storage unit 3 equipped with a hot water storage tank 2, a heat pump unit 4 as a heat source device, and, for example, a combustion-type auxiliary heat source device 5. This hot water storage and hot water supply device 1 performs a hot water storage operation in which hot water heated to a predetermined target hot water storage temperature by the heat pump unit 4 is stored in the hot water storage tank 2. The auxiliary heat source device 5 supplies the hot water discharged from the hot water storage unit 3 to the hot water supply tap 6 either heated or unheated depending on the temperature of the hot water, in order to supply hot water at a hot water supply setting temperature from the hot water supply tap 6 as shown by the arrow HW.

Next, the hot water storage unit 3 will be described.
A supply passage 8 equipped with a hot water storage pump 7 is connected to the bottom of the hot water storage tank 2 in order to supply hot water from the hot water storage tank 2 to the heat pump unit 4. A return passage 9 is connected to the top of the hot water storage tank 2 in order to store the hot water heated by the heat pump unit 4 in the hot water storage tank 2. A changeover valve 10 for switching the flow path of the hot water is disposed midway through the return passage 9, and a return branch passage 9a branched off from the return passage 9 at this changeover valve 10 is connected to a portion of the supply passage 8 upstream of the hot water storage pump 7.

A return temperature sensor 9b is disposed upstream of the switching valve 10 in the return passage 9 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 starting the heat pump unit 4 is lower than a predetermined hot water set temperature, the switching valve 10 can be switched from the hot water tank 2 side to the return branch passage 9a side to circulate the hot water without returning it to the hot water tank 2 until it can be heated sufficiently.

A water supply passage 11 is connected to the bottom of the hot water storage tank 2, supplying clean water as indicated by the arrow CW. A hot water outlet passage 12 is connected to the top of the hot water storage tank 2, for discharging hot water from the hot water storage tank 2 from the hot water storage unit 3. A mixing valve 14 is provided midway along the hot water outlet passage 12, and a water supply branch passage 11a that branches off from midway along the water supply passage 11 is connected to the mixing valve 14. The hot water from the hot water storage tank 2 and the clean water from the water supply branch passage 11a are mixed by the mixing valve 14 and discharged from the hot water storage unit 3. The mixing valve 14 opens to increase the opening degree of the high temperature water side of the hot water storage tank 2 while decreasing the opening degree of the clean water side of the water supply branch passage 11a.

The hot water storage tank 2 has multiple hot water temperature sensors 2a-2d arranged at a predetermined interval in the vertical direction, which can detect the temperature of the hot water stored in the hot water storage tank 2 and the amount of hot water stored at that temperature. In order to prevent the temperature of the stored hot water from dropping, insulation material (not shown) is arranged to cover the hot water temperature sensors 2a-2d and the hot water storage tank 2.

A water supply temperature sensor 11b is provided in the water supply passage 11 to detect the temperature (water supply temperature) of the clean water flowing through the water supply passage 11. A water outlet flow rate sensor 12a is provided in the hot water outlet passage 12 to detect the hot water outlet flow rate from the hot water storage unit 3, a hot water storage tank outlet water temperature sensor 12b is provided in the hot water outlet passage 12 to detect the temperature of the hot water that is discharged from the hot water storage tank 2 and supplied to the mixing valve 14, and an outlet water temperature sensor 12c is provided in the hot water outlet passage 12 to detect the hot water outlet temperature from the hot water storage unit 3. The hot water outlet passage 12 is connected to the water supply port 5a of the auxiliary heat source unit 5 by a hot water passage 15, and the hot water supply port 5b of the auxiliary heat source unit 5 is connected to the hot water tap 6 by a hot water passage 16.

The hot water storage unit 3 has a hot water storage unit control unit 18 (control unit) that, for example, controls the hot water storage operation and controls the temperature adjustment of the hot water discharged 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 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. When the hot water outlet flow rate sensor 12a detects a flow rate equal to or greater than a predetermined flow rate, the mixing ratio of the mixing valve 14 is adjusted based on the temperatures detected by the water supply temperature sensor 11b and the hot water storage tank outlet temperature sensor 12b, and hot water is discharged so that the temperature detected by the outlet temperature sensor 12c becomes the predetermined outlet temperature.

An operation terminal 19 is connected to the hot water storage unit control unit 18 and the auxiliary heat source unit 5, allowing the hot water user to set, for example, the hot water supply temperature setting. A plurality of operation terminals 19 may be connected, and an operation terminal 19 corresponding to the hot water storage unit 3 may be connected to the hot water storage unit control unit 18, and an operation terminal corresponding to the auxiliary heat source unit 5 may be connected to the auxiliary heat source unit 5. Although not shown in the figure, the operation terminal 19 is equipped with a display unit for operation information, etc., an operation unit, and an audio output unit.

Next, the hot water storage operation will be described.
The hot water storage unit control unit 18 learns and stores the time of hot water use, the amount used, etc. as a hot water use history, and predicts the start time of future hot water use, the amount used, etc. based on this hot water use history. Then, it performs a hot water storage operation to store the amount of heat required equivalent to the predicted amount of use until the predicted hot water use start time. The control of this hot water storage operation will be described based on the flowchart in Figure 2. In the figure, Si (i = 1, 2, ...) represents a step.

When hot water storage operation control is started, in S1, a target hot water storage temperature and hot water storage amount for storing the required heat amount based on the prediction of hot water use are set, and the process proceeds to S2. The target hot water storage temperature is set higher than the hot water supply setting temperature and as low as possible within the range in which the required heat amount can be stored, so as to improve the operating efficiency of the heat pump unit 4. Since the capacity of the hot water storage tank 2 is limited, the target hot water storage temperature is set higher as the required heat amount increases. Note that the hot water stored in the hot water storage tank 2 is often used up before the next hot water storage operation, but if hot water at a temperature that can be used for hot water remains, the required heat amount can be stored by combining the heat of the remaining hot water.

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 the user can touch the temperature for a short period of time without risking burns, and is set to, for example, 50°C. If the determination in S2 is Yes, the process proceeds to S3, where hot water storage at the target hot water storage temperature is started, and the process proceeds to S4. Next, in S4, it is determined whether the set hot water storage amount has been reached. If the determination in S4 is No, hot water storage is continued and the process returns to S4, and if the determination in S4 is Yes, the process proceeds to S5. Then, in S5, hot water storage is stopped, and hot water storage operation control is terminated.

On the other hand, if the judgment in S2 is No (if the target hot water storage temperature is equal to or higher than the high temperature reference temperature), the process proceeds to S6, where it is judged whether or not the hot water storage unit 3 is currently discharging hot water. If the judgment in S6 is Yes, the process proceeds to S7, where it is judged whether or not there is hot water in the hot water storage tank 2 at a temperature that can be used for hot water supply. If the judgment in S7 is Yes, the process proceeds to S8, where it is judged whether or not there is an abnormality in the temperature of the hot water currently being discharged by the hot water storage unit 3. If the judgment in S8 is Yes, there is no abnormality in the mixing valve 14, so the hot water storage amount set at the target hot water storage temperature set as described above is stored and the hot water storage operation control is terminated. If the judgment in S8 is No, there is an abnormality in the mixing valve 14, so the process proceeds to S17 for the operation when an abnormality occurs in the mixing valve, which will be described later.

On the other hand, if the determination in S6 is No or if the determination in S7 is No, the process proceeds to S9. Then, in S9, a check of the operation 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 the origin, for example, with the water side fully open position as the origin, and checking that the origin position has been reached. If the mixing valve 14 is already in the origin position when the operation check begins, it is driven to close the water side and open the hot water tank side before being returned to the origin. If there is no hot water in the hot water tank 2 at a temperature that can be used for hot water supply, low-temperature hot water is heated by the auxiliary heat source unit 5 to supply hot water, so even if an operation check is performed, low-temperature hot water is supplied to the auxiliary heat source unit 5, and hot water supply is not hindered.

Next, in S10, while checking the operation of the mixing valve 14, it is determined whether or not there is a request to supply hot water to the hot water storage unit 3. If the determination in S10 is Yes, the process proceeds to S11, where it is determined whether or not there is hot water in the hot water storage tank 2 that is at a temperature that can be used for hot water supply.

If the determination in S11 is Yes, proceed to S12, where the hot water supply request is prioritized, the check of the operation of the mixing valve 14 is stopped, and hot water is mixed and discharged by the mixing valve 14 to the hot water supply set temperature, and proceed to S13. In S13, it is determined whether there is an abnormality in the hot water discharge temperature of the hot water storage unit 3 compared with the hot water supply set temperature. If the determination in S13 is No, there is no abnormality in the mixing valve 14, so proceed to S3, and as already explained, the set amount of hot water is stored at the set target hot water storage temperature, and the hot water storage operation control is terminated. If the determination in S13 is Yes, an abnormality in the mixing valve 14 has been detected, so proceed to S17.

If the determination in S11 is No, proceed to S14, where hot water is dispensed while checking the operation of the mixing valve 14, and then proceed to S15. Since there is no hot water in the hot water storage tank 2 at a temperature that can be used for hot water supply and hot water is heated and supplied by the auxiliary heat source unit 5, even if an operation check is performed, low-temperature hot water is supplied to the auxiliary heat source unit 5, and hot water supply is not interrupted. Also, if the determination in S10 is No, proceed to S15.

Next, in S15, it is determined whether or not 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 or not there is an abnormality in the mixing valve 14. For example, if the original position cannot be returned to or if the original position is clearly abnormal with respect 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, where the set amount of hot water is stored at the set target hot water temperature as already explained, and the hot water storage operation control is terminated.

If there is an abnormality in the mixing valve 14 and the judgment in S16 is Yes, if the judgment in S13 is Yes, or if the judgment in S8 is No, the process proceeds to S17, where an operation to be performed when an abnormality occurs in the mixing valve is performed. This operation to be performed when an abnormality occurs in the mixing valve prohibits the storage of hot water at a target hot water storage temperature equal to or higher than the high temperature reference temperature in order to avoid high-temperature hot water being discharged. In addition, the target hot water storage temperature equal to or higher than the high temperature reference temperature can be changed to a target hot water storage temperature below the high temperature reference temperature for storage of hot water. The user may operate the operation terminal 19 to select these.

When hot water storage at a target hot water storage temperature equal to or higher than the high temperature reference temperature is prohibited, as shown in FIG. 3, in S21, the operation terminal 19 notifies the user of the occurrence of an abnormality in the mixing valve 14, for example by display or sound, and the process proceeds to S22. Then, in S22, hot water storage at a target hot water storage temperature equal to or higher than the high temperature reference temperature is prohibited, the process returns, and the hot water storage operation control ends. When the next opportunity for hot water storage occurs while hot water storage at a target hot water storage temperature equal to or higher than the high temperature reference temperature is prohibited, the operation of the mixing valve 14 may not be checked, and hot water storage operation may be performed only if the target hot water storage temperature is below the high temperature reference temperature.

When storing hot water by changing the target hot water storage temperature to a temperature lower than the high temperature reference temperature, as shown in FIG. 4, in S31, the operation terminal 19 notifies the user of the occurrence of an abnormality in the mixing valve 14, for example by display or sound, and the process proceeds to S32. Next, in S32, the set target hot water storage temperature is changed to a temperature lower than the high temperature reference temperature, and the process proceeds to S33. Then, in S33, the set amount of hot water storage is changed to an amount of hot water storage corresponding to the changed target hot water storage temperature, and the process proceeds to S34.

Next, in S34, hot water storage at the changed target hot water storage temperature is started, and the process proceeds to S35, where it is determined whether the changed hot water storage amount has been reached. If the determination in S35 is No, hot water storage is continued and the process returns to S35. If the determination in S35 is Yes, the process proceeds to S36, where hot water storage is terminated and the process returns to end the hot water storage operation control. If the next opportunity to store hot water occurs while the abnormality in the mixing valve 14 has not been resolved, the operation of the mixing valve 14 may not be checked, and hot water may be stored as is if the target hot water storage temperature is below the high temperature reference temperature, or may be changed to a temperature below the high temperature reference temperature if the target hot water storage temperature is equal to or higher than the high temperature reference temperature and then stored.

The operation and effects of the above-mentioned hot water storage and supply device 1 will now be described.
In the hot water storage and heating system 1, which mixes high-temperature hot water stored in the hot water storage tank 2 with clean water through the mixing valve 14 to supply hot water, the operation of the mixing valve 14 is checked before the start of hot water storage when performing hot water storage operation at a target hot water storage temperature above the high-temperature reference temperature. Therefore, even if an abnormality in the mixing valve 14 is detected, high-temperature hot water discharge can be easily avoided because hot water above the high-temperature reference temperature has not yet been stored in the hot water storage tank 2. In addition, because the abnormality in the mixing valve 14 is detected before hot water storage, it is possible to detect an abnormality in the mixing valve 14 without interfering with hot water supply use.

When an abnormality is detected in the mixing valve 14 and hot water storage operation at a target temperature above the high temperature reference temperature is prohibited, hot water above the high temperature reference temperature, which could pose a risk of burns, is not stored in the hot water storage tank 2, so high-temperature hot water discharge can be prevented in advance.

When an abnormality in the mixing valve 14 is detected and the target temperature above the high temperature reference temperature is changed to below the high temperature reference temperature for hot water storage operation, hot water above the high temperature reference temperature, which may pose a risk of burns, is not stored in the hot water storage tank 2. Therefore, while preventing high-temperature hot water from being discharged, hot water below the high temperature reference temperature can be stored in the hot water storage tank 2 and used for hot water supply, and an increase in heating opportunities for the auxiliary heat source unit 5 is suppressed.

When a hot water supply request is made while checking the operation of the mixing valve 14, if there is hot water in the hot water storage tank 2 at a temperature that can be used for hot water supply, it is assumed that there was no abnormality during the previous operation check of the mixing valve 14, and the hot water supply request takes priority and the operation check is stopped. Therefore, hot water supply is not hindered. On the other hand, when a hot water supply request is made while checking the operation of the mixing valve 14, if there is no hot water in the hot water storage tank 2 at a temperature that can be used for hot water supply, low-temperature hot water is discharged for hot water supply regardless of the mixing ratio of the mixing valve 14, so the operation check of the mixing valve 14 continues. Therefore, it is possible to check the operation of the mixing valve 14 without hindering hot water supply and detect any abnormalities in the mixing valve 14.

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, so that an abnormality in the mixing valve 14 can be detected in advance. Even in a hot water storage and hot water supply system equipped with a hot water heating device that uses heat generated during power generation instead of the heat pump unit 4 as a heat source, it is possible to detect an abnormality by checking the operation of the mixing valve 14 as described above and prevent high-temperature hot water from being discharged. In addition, a person skilled in the art can implement the above embodiment in various modified forms without departing from the spirit of the present invention, and the present invention includes such modified forms.

1: Hot water storage and hot water supply device 2: Hot water storage tanks 2a to 2d: Hot water temperature sensor 3: Hot water storage unit 4: Heat pump unit (heat source unit)
5: Auxiliary heat source unit 5a: Water inlet 5b: Hot water supply port 6: Hot water tap 7: Hot water storage pump 8: Supply passage 9: Return passage 9a: Return branch passage 10: Switching valve 11: Water supply passage 11a: Water supply branch passage 11b: Water supply temperature sensor 12: Hot water outlet passage 12a: Hot water outlet flow rate sensor 12b: Hot water storage tank outlet hot water temperature sensor 12c: Hot water outlet temperature sensor 14: Mixing valve 15, 16: Hot water passage 18: Hot water storage unit control unit (control unit)
19: Operation terminal

Claims (4)

A hot water storage and hot water supply device having a heat source unit, a hot water storage tank, a control unit that controls a hot water storage operation in which hot water heated by the heat source unit is stored in the hot water storage tank, and a mixing valve that mixes the hot water discharged from the hot water storage tank with tap water to supply hot water,
The hot water storage and hot water supply device is characterized in that, when the target hot water temperature for the hot water storage operation is equal to or higher than a predetermined high temperature reference temperature, the control unit checks the operation of the mixing valve before starting hot water storage for the hot water storage operation. The hot water storage and hot water supply device according to claim 1, characterized in that the control unit prohibits hot water storage at a target hot water storage temperature equal to or higher than the high temperature reference temperature if an abnormality is detected during the operation check of the mixing valve. The hot water storage and hot water supply device according to claim 1, characterized in that, when an abnormality is detected during the operation check of the mixing valve, the control unit changes the target hot water storage temperature of the hot water storage operation to a temperature lower than the high temperature reference temperature and stores hot water. A hot water storage and hot water supply device as described in any one of claims 1 to 3, characterized in that when a hot water supply request is made during operation check of the mixing valve, if there is hot water in the hot water storage tank at a temperature sufficient for hot water supply, the control unit stops the operation check and controls the mixing by the mixing valve to supply hot water, and if there is no hot water in the hot water storage tank at a temperature sufficient for hot water supply, the control unit continues the operation check.

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