JP7478927B2 - Hot water storage and heating equipment - Google Patents

Description

The present invention relates to a hot water storage and hot water supply system that supplies hot water that is heated by a heat pump heat source and stored in a hot water storage tank, and in particular to a hot water storage and hot water supply system that performs a heat sterilization operation on the hot water storage tank when hot water has been retained in the hot water storage tank for a long period of time.

Traditionally, hot water storage and supply systems have been widely used, which supply hot water stored in a hot water storage tank using a hot water storage operation. The hot water storage tank from which the hot water is drawn is supplied with clean water to which chlorine-based disinfectants have been added, so there is almost no chance of bacteria growing inside the hot water storage tank.

However, if the hot water stored during hot water storage operation remains unused, there is a non-zero possibility that bacteria such as Legionella bacteria will grow. It is unhygienic to supply hot water that has remained in the water for such a long time from the shower, and there is also a risk of health problems if the bacteria are taken into the body.

For this reason, the hot water storage and supply system sets a retention time that allows hot water to remain in the hot water storage tank, and measures the retention time of the hot water. If the entire amount of hot water in the hot water storage tank is replaced within the retention time, the retention time measurement starts from zero. On the other hand, if the measured retention time exceeds the retention time, i.e., if there is hot water that has been retained in the hot water storage tank for longer than the retention time, a heat sterilization operation is performed, for example as described in Patent Document 1, and the entire amount of hot water in the hot water storage tank is heated to a high temperature and sterilized.

JP 2013-224786 A

In hot water heated to a high temperature of 60°C or higher by the heat sterilization operation, Legionella bacteria and the like are almost completely killed in a short time. If the hot water storage and hot water supply system is equipped only with a heat pump heat source unit as the heat source unit for heating the hot water in the hot water storage tank, the heat sterilization operation is performed by using this heat pump heat source unit to heat the water to a high temperature of 60°C or higher (for example, 65°C).

A heat pump heat source unit transfers heat from the outside air to hot water to heat it, so the higher the outside air temperature, the easier it is to heat the hot water. However, since there is a risk that the heat pump heat source unit will become too hot, Patent Document 1 prohibits heat sterilization operation when the outside air temperature is high. On the other hand, the lower the outside air temperature, the less heat is transferred, so the longer it takes for the heat pump heat source unit to heat the hot water to a high temperature. And since it is difficult to heat the hot water below a certain standard outside air temperature, the operation of the heat pump heat source unit is prohibited.

The hot water storage and hot water supply system cannot supply hot water until the heat sterilization operation is completed, so if the heat sterilization operation takes a long time when the outside temperature is low, there is a risk that users of the hot water storage and hot water supply system will be inconvenienced and feel uncomfortable. In addition, there is an issue that energy consumption increases due to the long heat sterilization operation.

The object of the present invention is to provide a hot water storage and supply system that can properly perform heat sterilization operation using a heat pump heat source unit.

The hot water storage and hot water supply system of the invention of claim 1 stores hot water heated using a heat pump heat source unit in a hot water storage tank, and when hot water has remained in the hot water storage tank for more than a preset retention time, performs a heating and sterilizing operation of the hot water in the hot water storage tank using the heat pump heat source unit, and is characterized in that the system is equipped with a weather information acquisition means for acquiring weather information from an external communication network, schedules the date and time of the heating and sterilizing operation on a date and time that corresponds to the retention time, and when the acquired weather information shows that the predicted temperature at the scheduled date and time of the heating and sterilizing operation is below a predetermined temperature, changes the scheduled date and time of the heating and sterilizing operation to the date and time of the period with the highest predicted temperature within a predetermined period before and after the scheduled date and time .

According to the above configuration, the heat sterilization operation performed using the heat pump heat source unit is scheduled for the date and time that corresponds to the retention setting time. Then, the scheduled date and time of the heat sterilization operation is changed according to the weather information acquired by the weather information acquisition means. Therefore, the scheduled date and time of the heat sterilization operation can be changed to a time period suitable for the heat sterilization operation using the heat pump heat source unit based on the weather information. Then, when the heat sterilization operation is performed on the changed scheduled date and time, it is possible to shorten the time required for the heat sterilization operation and reduce the energy consumption of the heat sterilization operation.

If it is predicted that the time required for the heat sterilization operation using a heat pump heat source unit will be long or that the heat sterilization operation cannot be performed due to a predicted temperature below a predetermined temperature at the scheduled date and time of the heat sterilization operation, the scheduled date and time of the heat sterilization operation can be changed to the date and time of the time period with the highest predicted temperature suitable for heating with the heat pump heat source unit within a specified period before and after the scheduled date and time of the heat sterilization operation.

The hot water storage and supply system of the present invention according to claim 2 is the hot water storage and supply system according to claim 1 , characterized in that a change in the scheduled date and time of the heat sterilization operation is notified.
According to the above configuration, users of the hot water storage and hot water supply system can be notified in advance of the time when the heating and sterilization operation will be performed, which will make it impossible to supply hot water, thereby reducing the discomfort felt by users due to the inability to supply hot water.

The hot water storage and hot water supply system of the present invention can change the time to perform heat sterilization operation using a heat pump heat source unit to an appropriate time. This allows the hygienic condition inside the hot water storage tank to be maintained, while shortening the time required for heat sterilization operation to reduce discomfort that may be caused to users, and also reduces the energy consumption of heat sterilization operation.

1 is a configuration diagram of a hot water storage and hot water supply system according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the measurement of retention time and the amount of tapped water stored in accordance with an embodiment of the present invention. 4 is a control flowchart for the heat sterilization operation of the hot water storage and hot water supply system according to the embodiment of the present invention. FIG. 2 is a diagram showing an example of a weekly weather forecast according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a three-day weather forecast according to an embodiment of the present invention.

The following describes an embodiment of the present invention with reference to Figures 1 to 5. The following description of the preferred embodiment is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

As shown in Fig. 1, the hot water storage and supply system 1 includes a hot water storage and supply unit 3 equipped with a hot water storage tank 2 for storing hot water, and a heat pump heat source unit 4 for heating the hot water in the hot water storage tank 2. The hot water storage and supply unit 3 includes a mixer 5 for mixing the hot water in the hot water storage tank 2 with clean water in order to adjust the temperature of the hot water to be supplied. The hot water storage tank 2 is equipped with dish-shaped or semi-elliptical mirror plates on both ends (top and bottom) of the cylindrical container and is configured in an airtight manner to prevent exposure to outside air.

A heat source passage 6 is connected to the bottom of the hot water storage tank 2 to supply hot water from the hot water storage tank 2 to the heat pump heat source unit 4. A heat source passage 6 is provided in the heat source passage 6 to detect the temperature of the hot water supplied to the heat pump heat source unit 4.

A heat source return passage 7 is connected to the top of the hot water storage tank 2 for returning the hot water heated by the heat pump heat source unit 4 to the hot water storage tank 2. A heat source return temperature sensor 7a is disposed in the heat source return passage 7 to detect the temperature of the hot water heated by the heat pump heat source unit 4.

The heat pump heat source unit 4 performs hot water storage operation by heating the hot water in the hot water storage tank 2 supplied via the heat source unit forward passage 6, and returning the heated hot water to the top of the hot water storage tank 2 via the heat source unit return passage 7 for storage. In order to circulate the hot water in the hot water storage tank 2 between the heat pump heat source unit 4 during hot water storage operation, a pump not shown is provided in the heat pump heat source unit 4, but a pump may also be provided in the heat source unit forward passage 6 of the hot water storage and hot water supply unit 5. The heat pump heat source unit 4 is also provided with an outside air temperature sensor not shown.

A water supply passage 8 is connected to the bottom of the hot water storage tank 2 as shown by the arrow CW, for supplying clean water from the water supply to the hot water storage tank 2. The water supply passage 8 has a water supply valve 8a for opening and closing the passage, and a water supply temperature sensor 8b for detecting the water supply temperature. A drain passage 9 having a drain valve 9a is connected near the connection of the water supply passage 8 with the hot water storage tank 2. A hot water outlet passage 10 is connected to the top of the hot water storage tank 2, for supplying hot water from the hot water storage tank 2 to the mixing device 5.

In the hot water storage tank 2, multiple hot water temperature sensors 2a to 2e are arranged at predetermined intervals in the vertical direction of the hot water storage tank 2 to detect the temperature of the hot water inside. The hot water storage tank 2 and the hot water temperature sensors 2a to 2e are covered on the outside with a heat insulating material (not shown), which suppresses the loss of heat from the hot water stored during hot water storage operation.

The mixing device 5 is connected to a hot water outlet passage 10, a water supply branch passage 11 branched off from the water supply passage 8, and a hot water supply passage 12. The mixing device 5 is configured to be able to adjust the mixing ratio of the high-temperature hot water supplied from the hot water outlet passage 10 and the low-temperature clean water supplied from the water supply branch passage 11. The hot water mixed in the mixing device 5 is supplied to a hot water tap (not shown) via the hot water supply passage 12 as indicated by the arrow HW.

A mixing device inlet temperature sensor 10a is provided in the hot water outlet passage 10 near the high-temperature water inlet of the mixing device 5 to detect the temperature of the hot water supplied to the mixing device 5. A hot water supply flow rate sensor 12a that detects the hot water supply flow rate and a hot water supply temperature sensor 12b that detects the hot water supply temperature are provided in the hot water supply passage 12.

The hot water storage and hot water supply system 1 is equipped with a control unit 14 for controlling hot water storage operation, heat sterilization operation, etc. The control unit 14 controls various operations by operating the heat pump heat source unit 3, the mixing device 5, etc. based on the detected temperatures of temperature sensors arranged in various parts such as the hot water storage temperature sensor 2a, and the detected flow rates of the hot water supply flow rate sensor 12a, etc. The control unit 14 also has a timing function and a function for storing the hot water output amount as operation history information.

In order to operate the hot water storage and hot water supply system 1 and to set various settings such as the hot water supply temperature setting, an operation terminal 15 having a display unit 15a that also serves as a touch panel type operation unit is communicatively connected to the control unit 14. The hot water storage and hot water supply unit 3 and the heat pump heat source unit 4 are installed outdoors, and the operation terminal 15 is attached to a wall inside the room. The display unit 15a displays information such as the hot water supply temperature setting and operating status of the hot water storage and hot water supply system 1. The operation terminal 15 may be equipped with an audio output unit that outputs an alarm sound, etc., and the operation unit may be provided separately from the display unit 15a.

The operation terminal 15 has a wireless communication function and is communicatively connected to the line termination device 16 so as to enable wireless communication with the line termination device 16 having a router function. The line termination device 16 is communicatively connected to an external communication network 18 (Internet) via a home communication line 17. The control unit 14, which has a function of acquiring weather forecast information (weather information) and the like from the communication network 18 via the operation terminal 15, corresponds to weather information acquisition means. The communication connection between the operation terminal 15 and the line termination device 16 may be a wired communication connection, or the control unit 14 may be communicatively connected directly to the line termination device 16.

Next, the hot water storage operation will be described.
The control unit 14 performs hot water storage operation at a set time, and fills the hot water storage tank 2 with hot water at a temperature higher than the hot water supply setting temperature (for example, 50°C). For example, when the system is set to use nighttime electricity when electricity rates are low, the hot water storage operation is performed using nighttime electricity. When an operation to start the hot water storage operation is performed from the operation terminal 15, the control unit 14 starts the hot water storage operation.

Next, the hot water supply operation will be described.
In hot water supply operation, the control unit 14 calculates the mixing ratio of the mixer 5 based on the detected temperatures and detected flow rates of the mixer inlet temperature sensor 10a, the water supply temperature sensor 8b, the hot water supply flow rate sensor 12a, and the hot water supply temperature sensor 12b. The mixing ratio of the mixer 5 is then adjusted to the calculated mixing ratio, thereby supplying hot water adjusted to the hot water supply set temperature. At this time, clean water equivalent to the hot water output from the hot water storage tank 2 is supplied from the water supply passage 8 to the hot water storage tank 2. The control unit 14 also calculates and stores the hot water output from the hot water storage tank 2 based on the detected flow rate of the hot water supply flow rate sensor 12a and the mixing ratio of the mixer 5.

Next, the proliferation of bacteria in the hot water tank 2 will be described.
A temperature suitable for growth is necessary for the proliferation of bacteria in the hot water storage tank 2. For example, it is known that Legionella bacteria double every 4 to 6 hours in a temperature range of about 20°C to 45°C, which is suitable for proliferation, and that proliferation is inhibited at low temperatures below 10°C, and that they are almost completely killed within a short period of time at temperatures above 60°C.

Since chlorine-based disinfectant is added to the drinking water, when the hot water storage tank 2 is filled with fresh drinking water, there are virtually no germs in the tank, and there is almost no risk of germs growing due to stagnation. However, the possibility of germs being present is not zero, and the residual chlorine concentration of stagnant drinking water gradually decreases, so the longer the stagnation time, the greater the risk of germs growing. In particular, when hot water heated by the hot water storage operation stagnates, it reaches a temperature suitable for germs growing, further increasing the risk of germs growing.

Since it is generally difficult to count the total number of growing bacteria, the number of growing bacteria is expressed using colony forming units (CFU), which count the number of colonies formed when the bacteria are cultured. Since the possibility of the presence of unwanted bacteria in the hot water storage tank 2 is not zero, it is assumed that there is a minimum of 1 [CFU] of unwanted bacteria in the hot water storage tank 2, and the temperature, capacity of the hot water storage tank 2, etc. are taken into consideration, and the retention time that allows retention is set in advance, for example to 100 hours.

If hot water remains in the hot water storage tank 2 for longer than the retention setting time without being discharged, there is a risk that germs that may be contained in the hot water will grow and spread throughout the hot water in the hot water storage tank 2. Therefore, the control unit 14 measures the retention time of the hot water and schedules the heat sterilization operation of the hot water storage tank 2 on the date and time when this retention time reaches the retention setting time.

For example, as shown in FIG. 2, the control unit 14 measures the retention time of hot water in the hot water storage tank 2 and calculates the accumulated hot water volume from the stored hot water output volume. In addition, the heat sterilization operation is scheduled for the first time on the date and time when the measured retention time reaches the retention setting time. This scheduled date and time can be changed.

As shown by broken line L1, if the scheduled date and time for heat sterilization operation arrives before the accumulated amount of hot water reaches the capacity V (e.g., 200 liters) of the hot water storage tank 2, heat sterilization operation is performed in the hot water storage tank 2. When the heat sterilization operation ends, the control unit 14 resets the accumulated amount of hot water and the retention time to zero, moves on to timing the next retention time, starts timing the next retention time, and sets the schedule for the next heat sterilization operation.

On the other hand, as shown by broken line L2, if the accumulated hot water volume reaches the capacity V of the hot water storage tank 2 before the scheduled date and time of the heat sterilization operation and the entire amount of hot water and water in the hot water storage tank 2 is replaced, the control unit 14 resets the accumulated hot water volume and retention time to zero. Then, without performing the scheduled heat sterilization operation, it moves on to timing the next retention time and sets a schedule for the next heat sterilization operation. In this case, when the hot water supply operation when the accumulated hot water volume exceeds the capacity of the hot water storage tank 2 ends, it starts timing the next retention time.

Next, the heat sterilization operation will be described.
In the heat sterilization operation, in order to heat and sterilize the entire amount of hot water in the hot water storage tank 2, the heat pump heat source unit 4 is used to heat the entire amount of hot water in the hot water storage tank 2 to, for example, 65° C. or higher. The hot water heated by the heat pump heat source unit 4 is stored from the top of the hot water storage tank 2. When high-temperature hot water is stored up to the bottom of the hot water storage tank 2 and the temperature detected by the heat source unit supply temperature sensor 6a becomes, for example, 65° C. or higher, the entire amount is considered to have been heated, and the heat sterilization operation is terminated.

The heat pump heat source unit 4 transfers heat from the outside air to the hot water to heat it, so the lower the outside air temperature, the longer the time required for heat sterilization operation. When the outside air temperature is below the standard outside air temperature (e.g., below -7°C), it is difficult to heat the water using the heat pump heat source unit 4, so the operation of the heat pump heat source unit 4 is prohibited. In this case, heat sterilization operation using the heat pump heat source unit 4 is not possible, so the control unit 14 drains all of the hot water in the hot water storage tank 2. For example, the water supply valve 8a of the water supply passage 8 is closed and the drain valve 9a of the drain passage 9 is opened to drain the hot water storage tank 2. After the entire amount of the hot water storage tank 2 has been drained, the drain valve 9a is closed and the water supply valve 8a is opened to fill the hot water storage tank 2 and the drained passage with clean water.

As described above, the control unit 14 first schedules the heat sterilization operation on the date and time when the measured residence time reaches the residence setting time. However, since the outside air temperature at this scheduled date and time may not be suitable for heat sterilization operation using the heat pump heat source unit 4, the control unit 14 changes the scheduled date and time according to weather information. The control of the heat sterilization operation by the control unit 14 will be explained based on the flowchart in Figure 3. In the figure, Si (i = 1, 2, ...) represents a step.

In S1, the scheduled date and time of the heat sterilization operation, the accumulated hot water volume, and the retention time are read, and the process proceeds to S2. Then, in S2, it is determined whether the accumulated hot water volume is less than the capacity of the hot water storage tank 2. If the determination in S2 is Yes, the process proceeds to S3, and if the determination in S2 is No, the process proceeds to S11.

In S3, it is determined whether the current date and time is not the scheduled date and time for the heat sterilization operation. If the determination in S3 is Yes, proceed to S4. If the determination in S3 is No, proceed to S8 to execute the heat sterilization operation.

In S4, weather information is obtained from the communication network 18, and from this weather information, the predicted temperature for the time period including the scheduled date and time of the heat sterilization operation, as well as the predicted temperatures for multiple time periods before and after that are obtained, and the process proceeds to S5. As weather information, for example, as shown in FIG. 4, a weekly weather forecast including the current day includes information on the weather and predicted temperature every six hours. Also, as shown in FIG. 5, a three-day weather forecast including the current day, which is more detailed than the weekly weather forecast, includes information on the weather and predicted temperature every hour. The weather information is appropriately updated to information with increased accuracy over time. This weather information may be provided by a news site, or may be provided by the manufacturer of the hot water storage and supply system 1.

If the three-day weather forecast does not include the scheduled date and time of the heat sterilization operation, the predicted temperature for the time period including the scheduled date and time of the heat sterilization operation is obtained from the weekly weather forecast. In addition, the predicted temperatures for multiple time periods included in a specified period before the date and time when the residence time becomes the set residence time (the predicted temperatures within a specified time before and after the scheduled date and time) are obtained. The specified period is, for example, a period up to six hours before the date and time when the residence time becomes the set residence time, and the time width of this period can be set arbitrarily, but it is preferable that it be several hours because if it is too long, there is a risk of increased energy consumption.

For example, in FIG. 4, if the current date and time is Tuesday, and the scheduled date and time of the heat sterilization operation and the date and time of the set residence time are 3:00 on Saturday, the predicted temperatures are obtained for multiple time periods, some of which are included in the specified period, from 0:00 to 6:00 on Saturday and from 18:00 to 24:00 on Friday. Also, for example, in FIG. 5, if the current date and time is Thursday, the scheduled date and time of the heat sterilization operation is 21:00 on Friday, and the date and time of the set residence time is 3:00 on Saturday, the predicted temperatures are obtained for multiple time periods within the specified period (21:00, 22:00, 23:00, and 2:00 on Friday, and 1:00 and 2:00 on Saturday).

Next, in S5 of FIG. 3, it is determined whether the predicted temperature during the time period of the scheduled date and time of the heat sterilization operation is below a predetermined temperature (for example, 5°C). This is to determine whether efficient heating of hot water is possible using the heat pump heat source unit 4. For example, in FIG. 4, the predicted temperature from 0:00 to 6:00 on Saturday is 3°C, so the determination is Yes. If the determination in S5 is Yes, proceed to S6. Also, for example, in FIG. 5, the predicted temperature at 21:00 on Friday is 6°C, so the determination is No. If the determination in S5 is No, return is made without changing the scheduled date and time of the heat sterilization operation. The predetermined temperature can be set arbitrarily to a temperature higher than the standard outside air temperature.

In S6, it is determined whether or not there is a time period within a specified period before and after the scheduled date and time of the heat sterilization operation where the predicted temperature is higher than the predicted temperature during the time period of the scheduled date and time of the heat sterilization operation. For example, if the scheduled date and time of the heat sterilization operation and the date and time when the residence time becomes the residence setting time are 3:00 on Saturday, the predicted temperature obtained in S4 is 7°C from 18:00 to 24:00 on Friday in Figure 4, so the determination is Yes. If the determination in S6 is Yes, proceed to S7. If the determination in S6 is No, return without changing the scheduled date and time of the heat sterilization operation.

In S7, the scheduled date and time of the heat sterilization operation is changed to the date and time of the time zone with the highest predicted temperature within a specified period before and after the scheduled date and time of the heat sterilization operation, and the user is notified of this change and the process returns. The change is notified by displaying it on the display unit 15a of the operation terminal 15, but it may also be notified by transmitting the change details to a pre-registered smartphone or the like of the user via the communication network 18. If the user does not wish to be notified, the notification may be omitted.

For example, in the time period from 18:00 to 24:00 on Fridays in FIG. 4, the scheduled date and time of the heat sterilization operation is changed to 21:00 on Fridays within a specified period. In this way, the scheduled date and time of the heat sterilization operation is changed to a date and time suitable for heat sterilization operation within a specified period according to the weather information that is updated to information with high accuracy. The scheduled date and time that has been changed may also be changed later according to updated weather information.

On the other hand, if the determination in S3 in FIG. 3 is No, then in S8 it is determined whether the current outdoor air temperature is higher than the reference outdoor air temperature. This is to confirm that the temperature is not at which operation of the heat pump heat source unit 4 is prohibited. If the determination in S8 is Yes, then the process proceeds to S9, where a heat sterilization operation is performed, and once the heat sterilization operation is completed, the process proceeds to S11. If the determination in S8 is No, then the process proceeds to S10, where in S10 another anti-bacterial operation other than the heat sterilization operation is performed, for example by draining the entire hot water storage tank 2, and then proceeds to S11. Note that as an anti-bacterial operation, it is also possible to prohibit hot water supply until the outdoor air temperature becomes higher than the reference outdoor air temperature and the heat sterilization operation is performed and completed.

If the accumulated amount of hot water exceeds the capacity of the hot water storage tank 2, if a heat sterilization operation has been performed, or if a bacteria prevention operation such as drainage has been performed, in S11, the accumulated amount of hot water and the retention time are reset to zero, the scheduled date and time for the next heat sterilization operation is set to the date and time when the retention time is the set retention time, and then the process returns. As described above, the hot water storage and hot water supply system 1 maintains a sanitary condition inside the hot water storage tank 2, shortens the time required for the heat sterilization operation to reduce discomfort that may be caused to users, and reduces energy consumption during the heat sterilization operation.

The operation and effects of the hot water storage and supply system 1 will now be described.
The hot water storage and hot water supply system 1 supplies hot water that is heated using a heat pump heat source unit 4 and stored in a hot water storage tank 2. When hot water remains in the hot water storage tank 2 for a preset retention time or longer, a heat sterilization operation is performed using the heat pump heat source unit 4. The hot water storage and hot water supply system 1 includes a control unit 14 (weather information acquisition means) that acquires weather information from an external communication network 18 via an operation terminal 15.

The control unit 14 schedules the heat sterilization operation on the date and time when the initially measured residence time becomes the residence setting time. Then, this scheduled date and time is changed according to the acquired weather information. Therefore, the scheduled date and time can be changed to a time period with a predicted temperature suitable for heating by the heat pump heat source unit 4, and the heat sterilization operation can be efficiently executed. This shortens the time required for the heat sterilization operation and reduces the energy consumption of the heat sterilization operation.

In addition, if the expected temperature at the scheduled date and time of the heat sterilization operation is below a predetermined temperature among the acquired weather information, the scheduled date and time of the heat sterilization operation is changed. If it is difficult to efficiently heat hot water using the heat pump heat source unit 4 due to low outdoor air temperature below a predetermined temperature, the scheduled date and time of the heat sterilization operation is changed, so that the heat sterilization operation can be performed during a time period with an expected temperature suitable for heating using the heat pump heat source unit 4.

In addition, the user of the hot water storage and supply system 1 is notified of any changes to the scheduled date and time of the heat sterilization operation. This allows the user to be informed in advance that hot water cannot be supplied due to the heat sterilization operation, thereby reducing the discomfort of the user caused by not being able to supply hot water.

When the user does not wish to change the scheduled date and time of the heat sterilization operation or when the control unit 14 is not connected to the communication network 18, the hot water storage and hot water supply system 1 can be set to perform the heat sterilization operation when hot water has been retained for more than the retention setting time without changing the scheduled date and time. It is also possible to change the scheduled date and time of the heat sterilization operation to a date and time that exceeds the retention setting time, but for safety reasons, it is preferable to add a condition such as the accumulated hot water volume being zero.

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-mentioned embodiment without departing from the spirit of the present invention, and the present invention also includes such modifications.

1: Hot water storage and hot water supply system 2: Hot water storage tanks 2a to 2e: Hot water storage temperature sensor 3: Hot water storage and hot water supply unit 4: Heat pump heat source unit 5: Mixing device 6: Heat source unit forward passage 6a: Heat source unit forward temperature sensor 7: Heat source unit return passage 8: Water supply passage 8a: Water supply valve 8b: Water supply temperature sensor 9: Drain passage 9a: Drain valve 10: Hot water outlet passage 11: Water supply branch passage 12: Hot water supply passage 12a: Hot water supply flow rate sensor 12b: Hot water supply temperature sensor 14: Control unit 15: Operation terminal 15a: Display unit 16: Line termination device 17: Communication line 18: Communication network

Claims (2)

In a hot water storage and hot water supply system, hot water heated by a heat pump heat source device is stored in a hot water storage tank, and when hot water has remained in the hot water storage tank for a preset retention time or longer, the heat pump heat source device is used to perform a heating and sterilizing operation of the hot water in the hot water storage tank,
A weather information acquisition means for acquiring weather information from an external communication network,
A hot water storage and hot water supply system characterized in that the date and time of the heat sterilization operation is scheduled on a date and time that corresponds to the retention setting time, and if the predicted temperature at the scheduled date and time of the heat sterilization operation from the acquired weather information is below a predetermined temperature, the scheduled date and time of the heat sterilization operation is changed to the date and time of the period of time with the highest predicted temperature within a predetermined period before and after the scheduled date and time . The hot water storage and hot water supply system according to claim 1, characterized in that a change in the scheduled date and time of the heat sterilization operation is notified .