JP6741524B2 - Hot water supply system - Google Patents

Description

The technique disclosed in this specification relates to a hot water supply system.

The hot water supply system disclosed in Patent Document 1 includes a heat pump that absorbs heat from the outside air to boil water, a tank that stores hot water boiled by the heat pump, and a supply path that supplies hot water in the tank to hot water utilization points. And a setting means capable of setting the hot water supply set temperature at the hot water use location, and a control means. The control means can execute the boiling operation in which the water in the tank is heated to the boiling temperature by the heat pump. The hot water boiled by the heat pump is stored in the tank. After that, the temperature of the hot water in the tank decreases with time due to natural heat dissipation.

JP, 2005-038397, A

In the hot water supply system, when the boiling operation is executed at a low temperature, the COP (Coefficient Of Performance) of the heat pump can be made higher than when the boiling operation is executed at a high temperature. Therefore, it is preferable to execute the boiling operation at the lowest possible temperature.

On the other hand, if the boiling temperature is too low, the temperature of the hot water stored in the tank will decrease, and when supplying the hot water in the tank to the hot water use point, the hot water at the hot water set temperature can be supplied to the hot water use point. It may disappear. In particular, when the temperature of the hot water in the tank decreases over time due to natural heat dissipation, hot water at the hot water supply set temperature may not be supplied to the hot water use location. Therefore, the present specification provides a technique capable of suppressing the supply of hot water having a temperature lower than the hot water supply set temperature to hot water utilization points while increasing the COP when executing the boiling operation.

The hot water supply system disclosed in the present specification is a heat pump that absorbs heat from the outside air to boil water, a tank that stores hot water boiled by the heat pump, and a temperature sensor that measures the temperature of hot water stored in the tank. A supply path for supplying the hot water in the tank to the hot water use location, a setting means capable of setting a hot water supply set temperature at the hot water use location, and a control means. The control means can execute a first boiling operation in which the water in the tank is boiled to a first boiling temperature by a heat pump at a predetermined first boiling time. Further, the control means measures, with the temperature sensor, the first hot water storage temperature which is the temperature of the hot water in the tank when the hot water storage amount in the tank becomes less than the predetermined hot water storage amount after executing the first boiling operation. However, if the first hot water storage temperature is higher than the first reference temperature higher than the hot water supply set temperature, the first boiling temperature on the next day is lowered to make the second hot water storage temperature higher than the hot water supply set temperature and lower than the first reference temperature. When the temperature is lower than the reference temperature, the first boiling temperature of the next day is raised and the first boiling operation of the next day is executed.

According to such a configuration, when the control means executes the first boiling operation, the heat pump boil the water in the tank to the first boiling temperature. The hot water boiled by the heat pump is stored in the tank. Hot water having the first boiling temperature is stored in the tank. After that, when the hot water in the tank is supplied to the hot water use location, the amount of hot water stored in the tank decreases. Also, with the passage of time, the temperature of the hot water in the tank decreases due to natural heat dissipation. The control means measures the temperature of the hot water in the tank (that is, the first hot water storage temperature) when the amount of hot water stored in the tank becomes smaller than the predetermined amount of hot water storage. When the measured first hot water storage temperature is higher than the first reference temperature, the control means lowers the first boiling temperature of the next day. Further, when the measured first hot water storage temperature is lower than the second reference temperature, the control means raises the first boiling temperature of the next day. Then, the control means executes the first boiling operation at the predetermined first boiling time on the next day at the first boiling temperature lowered or the first boiling temperature raised.

According to the above configuration, when the temperature of the hot water remaining in the tank (first hot water storage temperature) is higher than the first reference temperature immediately before the hot water boiled in the first boiling operation is used up, the 1 Lower the boiling temperature. As a result, on the next day, it is possible to lower the first boiling temperature while maintaining the temperature of the hot water remaining in the tank just above the hot water supply set temperature immediately before the hot water boiled in the first boiling operation is used up. it can. In this way, when the first hot water storage temperature is high, the first boiling temperature of the next day is lowered in order to lower the first hot water storage temperature of the next day. Therefore, the first boiling temperature when executing the first boiling operation is The COP can be increased by lowering it.

When the temperature of the hot water remaining in the tank (first hot water storage temperature) is lower than the second reference temperature immediately before the hot water boiled in the first boiling operation is used up, the first boiling temperature of the next day is set to increase. As a result, on the next day, it is possible to reliably prevent the temperature of the hot water remaining in the tank from falling below the hot water supply set temperature immediately before the hot water boiled in the first boiling operation is used up. In this way, when the first hot water storage temperature is low, the first hot water storage temperature of the next day can be raised. Therefore, when supplying the hot water in the tank to the hot water use point, hot water at a temperature lower than the hot water supply set temperature is the hot water use point. Can be suppressed.

In the above hot water supply system, when the first hot water storage temperature is higher than the first reference temperature which is higher than the hot water supply set temperature, the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature and the first reference temperature from the first boiling temperature is used. If the first boiling temperature is set to the next day and the first hot water storage temperature is lower than the second reference temperature that is higher than the hot water supply set temperature and lower than the first reference temperature, the absolute value of the difference between the first hot water storage temperature and the second reference temperature is The temperature added to the one boiling temperature may be set as the first boiling temperature of the next day, and the first boiling operation of the next day may be executed.

With such a configuration, when lowering the first boiling temperature of the next day, the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature and the first reference temperature from the first boiling temperature is the first boiling temperature of the next day. By setting the temperature to be raised, it is possible to prevent the first boiling temperature on the next day from becoming too low. As a result, it is possible to prevent the temperature of the hot water remaining in the tank (the first hot water storage temperature of the next day) from becoming too low immediately before the hot water boiled in the first boiling operation of the next day is used up. On the other hand, when raising the first boiling temperature of the next day, the temperature obtained by adding the absolute value of the difference between the first hot water storage temperature and the second reference temperature to the first boiling temperature is set as the first boiling temperature of the next day. It is possible to prevent the first boiling temperature on the next day from becoming too high. As a result, it is possible to prevent the first hot water storage temperature of the next day from becoming too high. As a result, the first hot water storage temperature of the next day can be accurately brought close to the hot water supply set temperature.

Another hot water supply system disclosed in this specification is a heat pump that absorbs heat from the outside air to boil water, a tank that stores hot water boiled by the heat pump, and a temperature that measures the temperature of hot water stored in the tank. It is provided with a sensor, a supply path for supplying hot water in the tank to the hot water use point, a setting means capable of setting a hot water supply set temperature at the hot water use point, and a control means. The control means can execute the second boiling operation in which the water in the tank is boiled to the second boiling temperature by the heat pump at the second boiling time which is the last boiling time of the day. In addition, the control means uses the temperature sensor to detect the second hot water storage temperature, which is the temperature of the hot water in the tank when the hot water in the tank is supplied to the hot water use location at the end of the day after executing the second boiling operation. If the second hot water storage temperature is higher than the third reference temperature higher than the hot water supply set temperature, the second boiling temperature is decreased on the next day, and the second hot water storage temperature is higher than the hot water supply set temperature and lower than the third reference temperature. If the temperature is lower than the four reference temperature, the second boiling temperature of the next day is raised and the second boiling operation of the next day is executed.

According to this structure, when the control means executes the second boiling operation, the heat pump boil the water in the tank to the second boiling temperature. The hot water boiled by the heat pump is stored in the tank. Hot water having the second boiling temperature is stored in the tank. After that, when the hot water in the tank is supplied to the hot water use location, the amount of hot water stored in the tank decreases. Also, with the passage of time, the temperature of the hot water in the tank decreases due to natural heat dissipation. The control means measures the temperature of the hot water in the tank (that is, the second hot water storage temperature) when the hot water in the tank is supplied to the hot water utilization point at the end of the day. When the measured second hot water storage temperature is higher than the third reference temperature, the control means lowers the second boiling temperature on the next day. Further, when the measured second hot water storage temperature is lower than the fourth reference temperature, the control means raises the second boiling temperature of the next day. Then, the control means performs the second boiling operation at the second boiling time which is the last boiling time on the next day at the second boiling temperature lowered or the second boiling temperature raised above.

According to the above configuration, when the temperature of the hot water remaining in the tank (second hot water storage temperature) is higher than the third reference temperature at the end of the day after boiling in the second boiling operation, the next day Lower the second boiling temperature of. As a result, on the next day, the second boiling temperature can be lowered while maintaining the temperature of the hot water remaining in the tank at the end of the day at or above the hot water supply set temperature. As described above, when the second hot water storage temperature is high, the second boiling temperature of the next day is lowered in order to lower the second hot water temperature of the next day. Therefore, the second boiling temperature when executing the second boiling operation is set to The COP can be increased by lowering it.

Also, after boiling in the second boiling operation, if the temperature of the hot water remaining in the tank (second hot water storage temperature) at the end of the day is lower than the fourth reference temperature, the second boiling of the next day Raise the temperature. As a result, on the next day, it is possible to reliably prevent the temperature of the hot water remaining in the tank from falling below the hot water supply set temperature at the end of the day. In this way, when the second hot water storage temperature is low, the second hot water storage temperature of the next day can be raised. Therefore, when the hot water in the tank is supplied to the hot water use point, the hot water having a temperature lower than the hot water supply set temperature is the hot water use point. Can be suppressed.

In the above hot water supply system, when the second hot water storage temperature is higher than the third reference temperature which is higher than the hot water supply set temperature, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature and the third reference temperature from the second boiling temperature is used. If the second boiling temperature is set to the next day and the second hot water storage temperature is lower than the fourth reference temperature that is higher than the hot water supply set temperature and lower than the third reference temperature, the absolute value of the difference between the second hot water storage temperature and the fourth reference temperature is The temperature added to the second boiling temperature may be set as the second boiling temperature of the next day, and the second boiling operation of the next day may be executed.

With such a configuration, when lowering the second boiling temperature of the next day, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature and the third reference temperature from the second boiling temperature is the second boiling temperature of the next day. By setting the temperature to be raised, it is possible to prevent the second boiling temperature on the next day from becoming too low. As a result, it is possible to prevent the temperature of the hot water remaining in the tank (the second hot water storage temperature of the next day) from becoming too low at the end of the next day. On the other hand, when raising the second boiling temperature of the next day, the temperature obtained by adding the absolute value of the difference between the second hot water storage temperature and the fourth reference temperature to the second boiling temperature is set as the second boiling temperature of the next day. The second boiling temperature of the next day can be suppressed from becoming too high. As a result, it is possible to prevent the second hot water storage temperature of the next day from becoming too high. As a result, the second hot water storage temperature of the next day can be accurately brought close to the hot water supply set temperature.

Yet another hot water supply system disclosed in the present specification measures the temperature of a heat pump that absorbs heat from the outside air to boil water, a tank that stores hot water boiled by the heat pump, and the temperature of hot water stored in the tank. A temperature sensor, a supply path for supplying hot water in the tank to the hot water use point, a setting means capable of setting a hot water supply set temperature at the hot water use point, and a control means are provided. The control means performs a first boiling operation of boiling water in the tank to a first boiling temperature by a heat pump at a predetermined first boiling time and a second boiling time which is the last boiling time of the day. The water in the tank is boiled to the third boiling temperature by the heat pump during the second boiling operation in which the water in the tank is boiled to the second boiling temperature by the heat pump and the first boiling operation and the second boiling operation. It is possible to perform the third boiling operation of raising. Further, the control means measures, with the temperature sensor, the first hot water storage temperature which is the temperature of the hot water in the tank when the hot water storage amount in the tank becomes less than the predetermined hot water storage amount after executing the first boiling operation. However, if the first hot water storage temperature is higher than the first reference temperature higher than the hot water supply set temperature, the first boiling temperature on the next day is lowered to make the second hot water storage temperature higher than the hot water supply set temperature and lower than the first reference temperature. When the temperature is lower than the reference temperature, the first boiling temperature of the next day is raised and the first boiling operation of the next day is executed. In addition, the control means uses the temperature sensor to detect the second hot water storage temperature, which is the temperature of the hot water in the tank when the hot water in the tank is supplied to the hot water use location at the end of the day after executing the second boiling operation. If the second hot water storage temperature is higher than the third reference temperature higher than the hot water supply set temperature, the second boiling temperature is decreased on the next day, and the second hot water storage temperature is higher than the hot water supply set temperature and lower than the third reference temperature. If the temperature is lower than the four reference temperature, the second boiling temperature of the next day is raised and the second boiling operation of the next day is executed. Further, the control means sets a temperature between the first boiling temperature of the next day and the second boiling temperature of the next day between the first boiling operation of the next day and the second boiling operation of the next day to the third boiling temperature of the next day. As the raising temperature, the third boiling operation on the next day is executed.

According to such a configuration, with respect to the first boiling operation on the next day, while the COP when performing the boiling operation by lowering the first boiling temperature as much as possible, the hot water having a temperature lower than the hot water supply set temperature is It is possible to suppress the supply to the hot water utilization place, and regarding the second boiling operation of the next day, lower the second boiling temperature as much as possible and increase the COP when executing the boiling operation while setting the hot water supply set temperature. It is possible to prevent the lower temperature hot water from being supplied to the hot water use location.

Further, according to the above configuration, the third boiling temperature in the third boiling operation performed between the first boiling operation and the second boiling operation is set to the first boiling temperature and the second boiling temperature. The temperature is between. If the third boiling temperature is made extremely lower than the first boiling temperature and the second boiling temperature, the temperature of the hot water remaining in the tank during the third boiling operation will be the third boiling temperature. There is a possibility that the temperature stratification in the tank may be reversed because the temperature is higher than the temperature rise. On the contrary, if the third boiling temperature is made extremely higher than the first boiling temperature and the second boiling temperature, the temperature of the hot water remaining in the tank during the second boiling operation becomes the second temperature. Since the temperature is higher than the boiling temperature, the temperature stratification in the tank may be reversed. As described above, by setting the third boiling temperature to a temperature between the first boiling temperature and the second boiling temperature, the temperature stratification in the tank during the third boiling operation and the second boiling operation. Can be prevented from reversing.

As described above, according to the hot water supply system disclosed in the present specification, it is possible to suppress the supply of hot water having a temperature lower than the hot water supply set temperature to the hot water use location while increasing the COP when executing the boiling operation.

In the above hot water supply system, when the first hot water storage temperature is higher than the first reference temperature which is higher than the hot water supply set temperature, the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature and the first reference temperature from the first boiling temperature is used. If the first boiling temperature is set to the next day and the first hot water storage temperature is lower than the second reference temperature that is higher than the hot water supply set temperature and lower than the first reference temperature, the absolute value of the difference between the first hot water storage temperature and the second reference temperature is The temperature added to the one boiling temperature may be set as the first boiling temperature of the next day, and the first boiling operation of the next day may be executed. If the second hot water storage temperature is higher than the third reference temperature which is higher than the hot water supply set temperature, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature and the third reference temperature from the second boiling temperature is the second temperature of the next day. If the second hot water temperature is lower than the fourth reference temperature that is higher than the hot water supply set temperature and lower than the third reference temperature, the absolute value of the difference between the second hot water temperature and the fourth reference temperature is the second boiling temperature. The second boiling temperature of the next day may be set as the temperature of the second boiling temperature of the next day.

According to such a configuration, regarding the first boiling operation of the next day, the temperature of the hot water remaining in the tank immediately before the hot water boiled in the first boiling operation of the next day is used up (the first hot water storage temperature of the next day ) Can be accurately approached to a temperature close to the hot water supply set temperature. Further, regarding the second boiling operation on the next day, the temperature of the hot water remaining in the tank at the end of the day (the second hot water storage temperature on the next day) can be accurately brought close to the hot water supply set temperature.

The figure which shows typically the structure of the hot water supply system 2 which concerns on an Example. The graph which shows the relationship between the time regarding the 1st boiling operation, and the amount of hot water stored in the tank 10. The flowchart (1) which shows the control processing regarding the 1st boiling operation. The graph which shows the relationship between the time regarding the 1st boiling operation and the temperature of the hot water in the tank 10. The flowchart (2-1) which shows the control processing regarding the 1st boiling operation. The flowchart (2-2) which shows the control processing regarding the 1st boiling operation. The graph which shows the relationship between the time regarding the 2nd boiling operation, and the amount of hot water stored in the tank 10. The flowchart (1) which shows the control processing regarding the 2nd boiling operation. The graph which shows the relationship between the time regarding the 2nd boiling operation, and the temperature of the hot water in the tank 10. The flowchart (2-1) which shows the control processing regarding the 2nd boiling operation. The flowchart (2-2) which shows the control processing regarding the 2nd boiling operation. The graph which shows the relationship between the time regarding the 3rd boiling operation, and the amount of hot water stored in the tank 10. The flowchart (1) which shows the control processing regarding the 3rd boiling operation. The flowchart (2) which shows the control processing regarding the 3rd boiling operation. The flowchart which shows the method of calculating the amount of hot water stored in the tank.

The main features of the embodiments described below are listed. It should be noted that the technical elements described below are technical elements that are independent of each other and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Characteristic 1) The hot water supply system may further include an auxiliary heater that heats the hot water supplied from the tank to the hot water use location by burning the fuel.

When the heating source of the hot water is only the heat pump, if the temperature of the hot water in the tank becomes lower than the hot water supply set temperature, hot water supply at the hot water supply set temperature becomes impossible. For this reason, in the hot water supply system in which the heating source of the hot water is only the heat pump, the first reference temperature and the second reference temperature, and/or the third reference temperature and the fourth reference temperature are set to be higher and It is necessary to keep the boiling temperature in the raising operation at a relatively high temperature. In contrast to this, when the auxiliary heating device other than the heat pump is provided as the heating source for the hot water as in the hot water supply system described above, the temperature of the hot water in the tank is temporarily lower than the hot water set temperature. Even in this case, hot water can be supplied at the hot water supply set temperature by heating the hot water using the auxiliary heater. Therefore, according to the above hot water supply system, the first reference temperature and the second reference temperature, and/or the third reference temperature and the fourth reference temperature are set to lower temperatures, and the boiling temperature in the boiling operation is set. Lower temperatures can be used. Therefore, COP in the boiling operation can be further increased.

(Example)
FIG. 1 shows the configuration of a hot water supply system 2 according to this embodiment. As shown in FIG. 1, the hot water supply system 2 according to the present embodiment includes a tank 10, a tank water circulation path 20, a water supply path 30, a supply path 40, a heat pump 50, a burner heating device 60, and a controller 100. , Is provided.

The heat pump 50 is a heat source that absorbs heat from the outside air and heats the water in the tank water circulation path 20. The heat pump 50 is a device for boiling the water in the tank 10. The heat pump 50, which is not shown, is a heat medium circulation path that circulates a heat medium (for example, R32), an evaporator that performs heat exchange between outside air and the heat medium, and compresses the heat medium to a high temperature and high pressure. A compressor, a condenser that performs heat exchange between the water in the tank water circulation path 20 and the high-temperature and high-pressure heat medium, and an expansion valve that decompresses the heat medium after the heat exchange to reduce the temperature to a low pressure. Equipped with.

The tank 10 stores the hot water boiled by the heat pump 50. The tank 10 is of a hermetically sealed type, and its outside is covered with a heat insulating material. Water is stored in the tank 10 until it is full. In this embodiment, the capacity of the tank 10 is 100L. The thermistors 12, 14, 16, and 18 are attached to the tank 10 at predetermined intervals in the height direction of the tank 10. Each thermistor 12, 14, 16, 18 measures the temperature of the water at its mounting position. For example, each of the thermistors 12, 14, 16 and 18 measures the temperature of water at the positions of 6L, 12L, 30L and 50L from the top of the tank 10, respectively. A thermistor 11 (an example of a temperature sensor) is attached to the tank 10. The thermistor 11 is attached to the upper part of the tank 10 and measures the temperature of water stored in the upper part of the tank 10. The thermistor 11 measures the temperature of water immediately before it is discharged from the tank 10.

The tank water circulation path 20 has an upstream end connected to a lower portion of the tank 10 and a downstream end connected to an upper portion of the tank 10. A circulation pump 22 is interposed in the tank water circulation passage 20. The circulation pump 22 sends the water in the tank water circulation passage 20 from the upstream side to the downstream side. Further, the tank water circulation path 20 passes through a condenser (not shown) of the heat pump 50. Therefore, when the heat pump 50 is operated, the water in the tank water circulation passage 20 is heated by the condenser of the heat pump 50. Therefore, when the circulation pump 22 and the heat pump 50 are operated, the water in the lower portion of the tank 10 is heated by the heat pump 50, and the heated water is returned to the upper portion of the tank 10. That is, the tank water circulation path 20 is a water path for storing heat in the tank 10. Further, a thermistor 24 is provided on the upstream side of the heat pump 50 in the tank water circulation path 20. The thermistor 24 is led out from the lower portion of the tank 10 and measures the temperature of water before passing through the heat pump 50.

The water supply passage 30 has an upstream end connected to a tap water supply source 31. The water supply channel 30 supplies tap water to the tank 10. A thermistor 32 is provided in the water supply passage 30. The thermistor 32 measures the supply temperature of tap water. The downstream side of the water supply passage 30 branches into a first introduction passage 30a and a second introduction passage 30b. The downstream end of the first introduction path 30a is connected to the lower portion of the tank 10. The downstream end of the second introduction path 30b is connected in the middle of a supply path 40 described later. A mixing valve 42 is provided at a connection portion between the downstream end of the second introduction passage 30b and the supply passage 40. The mixing valve 42 adjusts the amount by which the hot water flowing in the supply passage 40 is mixed with the water in the second introduction passage 30b.

The upstream end of the supply path 40 is connected to the upper portion of the tank 10. As described above, the second introduction passage 30b of the water supply passage 30 is connected in the middle of the supply passage 40, and the mixing valve 42 is provided at the connection portion. A thermistor 43 is provided in the supply path 40 upstream of the mixing valve 42. The thermistor 43 measures the temperature of the hot water supplied from the tank 10 to the supply passage 40. A burner heating device 60 (an example of an auxiliary heater) is provided in the supply passage 40 on the downstream side of the connection portion with the second introduction passage 30b. Further, a thermistor 44 is provided in the supply path 40 on the downstream side of the burner heating device 60. The thermistor 44 measures the temperature of the hot water supplied to the hot water use location. The burner heating device 60 heats the water in the supply passage 40 so that the temperature of the hot water measured by the thermistor 44 matches the hot water supply set temperature. The burner heating device 60 heats water by burning fuel (for example, gas). The downstream end of the supply path 40 is connected to a hot water utilization point (for example, kitchen, bathtub, etc.).

The controller 100 (an example of a control unit) is electrically connected to each component and controls the operation of each component. The controller 100 is connected to a remote controller 104 (an example of a setting unit) having an operation unit that allows a user to input various instructions and a display unit that can display various information. The remote controller 104 can set the hot water supply set temperature at the hot water use location. In addition, the controller 100 includes a memory 102 (an example of a storage unit). The memory 102 can store various kinds of information.

Next, the operation of the hot water supply system 2 of this embodiment will be described. The hot water supply system 2 can execute a boiling operation and a hot water supply operation. Hereinafter, each operation will be described.

(Boiling operation)
The boiling operation is an operation in which the heat pump 50 heats the water in the tank 10. When execution of the boiling operation is instructed by the controller 100, the heat pump 50 starts operating and the circulation pump 22 rotates.

By operating the heat pump 50, the heat medium circulates in the heat medium circulation path. When the circulation pump 22 rotates, the water in the tank 10 circulates in the tank water circulation passage 20. That is, the water existing in the lower part of the tank 10 is introduced into the tank water circulation passage 20, and when the introduced water passes through the condenser, it is heated by the heat of the heat medium in the heat medium circulation passage and heated. Water is returned to the top of tank 10. As a result, high temperature water is stored in the tank 10. At the upper part of the tank 10, a temperature stratification in which a high temperature water layer is laminated on a low temperature water layer is formed.

(Hot water operation)
The hot water supply operation is an operation in which the water in the tank 10 is supplied to hot water utilization points. The hot water supply operation can be executed even during the above boiling operation. When the hot water tap at the hot water utilization point is opened, tap water flows from the tap water supply source 31 (first introduction path 30a) into the lower portion of the tank 10 due to the water pressure from the tap water supply source 31. At the same time, the hot water in the upper part of the tank 10 is supplied to the hot water utilization point via the supply path 40.

When the temperature of the water supplied from the tank 10 to the supply passage 40 (that is, the temperature measured by the thermistor 43) is higher than the hot water supply set temperature, the controller 100 opens the mixing valve 42 and supplies it from the second introduction passage 30b. Tap water is introduced into the passage 40. In this case, the water supplied from the tank 10 and the tap water supplied from the second introduction path 30b are mixed in the supply path 40. The controller 100 adjusts the opening degree of the mixing valve 42 so that the temperature of the hot water supplied to the hot water use location matches the hot water supply set temperature. On the other hand, the controller 100 operates the burner heating device 60 when the temperature of the hot water supplied from the tank 10 to the supply path 40 is lower than the hot water supply set temperature. In this case, the hot water passing through the supply passage 40 is heated by the burner heating device 60. The controller 100 controls the output of the burner heating device 60 so that the temperature of the hot water supplied to the hot water utilization point matches the hot water supply set temperature.

(First boiling operation)
Next, a control process in the hot water supply system 2 will be described. First, the control process regarding the first boiling operation will be described. To explain this, first, it is assumed that the user operates the remote controller 104 to set the hot water supply set temperature Ta at the hot water use location to 40° C. Further, as shown in FIG. 2, it is assumed that hot water is stored in the tank 10 at a certain time (for example, 18:00) on a certain day (for example, August 1). The hot water boiled by the heat pump 50 is stored in the tank 10. It is assumed that the amount of hot water stored in the tank 10 at 18:00 is 30 L (liter) or less.

In this situation, as shown in FIG. 3, in S9, the controller 100 determines whether or not the current time is the first boiling time. The first boiling time is set by a learning process based on the past boiling times, and is 18:00, for example. When the current time is the first boiling time, the controller 100 determines Yes in S9 and proceeds to S10. On the other hand, if the current time is not the first boiling time, the controller 100 determines No in S9 and stands by.

In subsequent S10, the controller 100 determines whether or not the boiling operation for boiling the water in the tank 10 by the heat pump 50 is being executed. If the boiling operation is being executed, the controller 100 determines Yes in S10, skips S11, and proceeds to S12. On the other hand, when the boiling operation is not being executed, the controller 100 determines No in S10 and proceeds to S11.

In subsequent S11, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 30 L or less. When the amount of hot water stored in the tank 10 is 30 L or less, the controller 100 determines Yes in S11 and proceeds to S12. On the other hand, when the amount of hot water stored in the tank 10 is not 30 L or less (more than 30 L), the controller 100 determines No in S11 and stands by. Whether or not the amount of hot water stored in the tank 10 is 30 L or less can be determined based on the measured temperature of the thermistor 16 attached to the 30 L position of the tank 10. When the measured temperature of the thermistor 16 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 30 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S12, the controller 100 permits the first boiling operation. When the controller 100 permits the first boiling operation, the first boiling operation is started. As described above, when the current time is the first boiling time (18:00) and the amount of hot water stored in the tank 10 is equal to or less than the predetermined amount (30 L) of hot water, the first boiling operation is started. It Further, when the boiling operation is already being executed, the boiling operation is switched to the first boiling operation. When the first boiling operation is started, the water in the tank 10 is boiled by the heat pump 50. The hot water boiled by the heat pump 50 is stored in the tank 10. Therefore, as shown in FIG. 2, the amount of hot water stored in the tank 10 increases after the first boiling time (18:00).

When executing the first boiling operation, the controller 100 executes the first boiling operation so that the warm water in the tank 10 reaches the first boiling temperature Tw1. The first boiling temperature Tw1 is initially set and is, for example, 45°C. Alternatively, the first boiling temperature Tw1 may be set by a learning process based on past boiling temperatures. The heat pump 50 heats the water in the tank 10 to the first boiling temperature Tw1. Hot water having the first boiling temperature Tw1 is stored in the tank 10.

In subsequent S13, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 100 L or more. When the amount of hot water stored in the tank 10 is 100 L or more, the controller 100 determines Yes in S13 and proceeds to S14. On the other hand, when the amount of hot water stored in the tank 10 is not 100 L or more (less than 100 L), the controller 100 determines No in S13 and stands by. The determination as to whether or not the amount of hot water stored in the tank 10 is 100 L or more can be made based on the temperature measured by the thermistor 24 provided on the upstream side of the heat pump 50. When the temperature measured by the thermistor 24 is equal to or higher than a predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is 100 L or more. The predetermined temperature serving as a criterion for judgment is, for example, the first boiling temperature-(minus) 5°C.

In subsequent S14, the controller 100 ends the first boiling operation. For example, as shown in FIG. 2, the hot water storage amount in the tank 10 becomes 100 L or more at 19:00, and the controller 100 ends the first boiling operation based on that.

When the hot water supply operation is executed after the completion of the first boiling operation, the hot water in the tank 10 is supplied from the tank 10 to the hot water utilization point, and the amount of hot water stored in the tank 10 decreases. For example, by filling the bathtub (an example of a hot water use location) with hot water, the amount of hot water stored in the tank 10 decreases. Then, it is assumed that the amount of hot water stored in the tank 10 becomes 12 L or less at 20:00.

As shown in FIG. 3, in subsequent S15, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 12 L or less. When the amount of hot water stored in the tank 10 is 12 L or less, the controller 100 determines Yes in S15 and proceeds to S16. On the other hand, when the amount of hot water stored in the tank 10 is not 12 L or less (more than 12 L), the controller 100 determines No in S15 and stands by. Whether or not the amount of hot water stored in the tank 10 is 12 L or less can be determined based on the measured temperature of the thermistor 14 attached to the 12 L position of the tank 10. When the measured temperature of the thermistor 14 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 12 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S16, the controller 100 measures the first hot water storage temperature Tb1 which is the temperature of the hot water in the tank 10. The first hot water storage temperature Tb1 is measured by the thermistor 11 attached to the upper portion of the tank 10. The measured temperature of the thermistor 11 is transmitted to the controller 100, and the controller 100 receives it. When the amount of hot water stored in the tank 10 becomes 6 L or less, the controller 100 determines that the tank 10 is out of hot water. Therefore, controller 100 measures first hot water storage temperature Tb1 when the amount of hot water stored in tank 10 is 12 L or less and more than 6 L. The amount of hot water stored in the tank 10 at this time can be regarded as the minimum amount of hot water stored in one day. The first hot water storage temperature Tb1 is the temperature of the hot water immediately before the tank 10 is out of hot water. That is, the first hot water storage temperature Tb1 is the temperature of the hot water remaining in the tank 10 immediately before the hot water boiled in the first boiling operation is used up.

As shown in FIG. 4, the temperature of the hot water in the tank 10 is the first boiling temperature Tw1 (for example, 45° C.) at 19:00 immediately after the completion of the first boiling operation. After that, as time passes, the temperature of the hot water in the tank 10 decreases due to natural heat dissipation. Therefore, when the amount of hot water stored in the tank 10 becomes 12 L or less at 20:00, the temperature of the hot water in the tank 10 is lower than the first boiling temperature Tw1. That is, the first hot water storage temperature Tb1 measured by the thermistor 11 is lower than the first boiling temperature Tw1. The first hot water storage temperature Tb1 varies depending on how the temperature of the hot water in the tank 10 decreases. The first hot water storage temperature Tb1 is, for example, 43° C. or 40° C.

As shown in FIG. 3, in subsequent S17, controller 100 stores measured first hot water storage temperature Tb1 in memory 102. After that, the controller 100 ends the process related to the first boiling operation on that day (August 1st). The first hot water storage temperature Tb1 on that day (August 1) is used to calculate the first boiling temperature Tw1 in the first boiling operation on the next day (August 2).

Next, the operation on the next day (August 2) will be described. Also on the next day (August 2), first, similarly to the previous day (August 1), it is assumed that the hot water supply set temperature Ta at the hot water use location is set to 40°C. Further, it is assumed that the hot water storage amount in the tank 10 at a certain time (18:00) is 30 L (liter) or less. In addition, in this specification, the following day will be described as August 2, and the previous day will be described as August 1. The next day (August 2) in this case is the next day to the previous day (August 1).

In this situation, as shown in FIG. 5A, in S19, the controller 100 determines whether or not the current time is the first boiling time. The first boiling time is set by a learning process based on the past boiling times, and is 18:00, for example. When the current time is the first boiling time, the controller 100 determines Yes in S19 and proceeds to S20. On the other hand, if the current time is not the first boiling time, the controller 100 determines No in S19 and waits.

In subsequent S20, the controller 100 determines whether or not the boiling operation of boiling the water in the tank 10 by the heat pump 50 is being executed. If the boiling operation is being executed, the controller 100 determines Yes in S20, skips S21, and proceeds to S22. On the other hand, when the boiling operation is not being executed, the controller 100 determines No in S20 and proceeds to S21.

In subsequent S21, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 30 L or less. When the amount of hot water stored in the tank 10 is 30 L or less, the controller 100 determines Yes in S21 and proceeds to S22. On the other hand, when the amount of hot water stored in the tank 10 is not 30 L or less (more than 30 L), the controller 100 determines No in S21 and stands by. Whether or not the amount of hot water stored in the tank 10 is 30 L or less can be determined based on the measured temperature of the thermistor 16 attached to the 30 L position of the tank 10. When the measured temperature of the thermistor 16 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 30 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S22, the controller 100 acquires the first hot water storage temperature Tb1 after executing the first boiling operation on the previous day (August 1). The first hot water storage temperature Tb1 of the previous day is stored in the memory 102.

In subsequent S23, the controller 100 acquires the first boiling temperature Tw1 when the first boiling operation on the previous day (August 1) was executed. The first boiling temperature Tw1 of the previous day is stored in the memory 102.

As shown in FIG. 5B, in subsequent S24, controller 100 determines whether or not first hot water storage temperature Tb1 of the previous day is higher than hot water supply set temperature Ta+ΔT1. ΔT1 is a preset temperature, for example, 2°C. If the first hot water storage temperature Tb1 of the previous day is higher than the hot water supply set temperature Ta+ΔT1, the controller 100 determines Yes in S24 and proceeds to S25. For example, if the first hot water storage temperature Tb1 of the previous day is 43° C., the first hot water storage temperature Tb1 (43° C.)>hot water supply set temperature Ta (40° C.)+ΔT1 (2° C.), and the controller 100 returns Yes in S24. to decide. Hot water supply set temperature Ta+ΔT1 is an example of the first reference temperature. The first reference temperature is a temperature that is higher than the hot water supply set temperature Ta by ΔT1.

In subsequent S25, the controller 100 calculates the first boiling temperature Tw1 of the next day (August 2). Specifically, the first boiling temperature Tw1 of the next day=the first boiling temperature Tw1 of the previous day−|the first hot water storage temperature Tb1−(hot water supply set temperature Ta+ΔT1)| of the previous day. That is, a temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature Tb1 of the previous day and the first reference temperature (hot water supply set temperature Ta+ΔT1) from the first boiling temperature Tw1 of the previous day is set as the first boiling temperature Tw1 of the next day. .. Therefore, the first boiling temperature Tw1 of the next day is lower than the first boiling temperature Tw1 of the previous day.

On the other hand, in S26 after determining No in S24, controller 100 determines whether or not first hot water storage temperature Tb1 of the previous day is lower than hot water supply set temperature Ta+ΔT2. ΔT2 is a preset temperature, for example, 1°C. ΔT2 is a temperature lower than ΔT1 (small value). If the first hot water storage temperature Tb1 of the previous day is lower than the hot water supply set temperature Ta+ΔT2, the controller 100 determines Yes in S26 and proceeds to S27. For example, when the first hot water storage temperature Tb1 of the previous day is 40° C., the first hot water storage temperature Tb1 (40° C.)<hot water supply set temperature Ta (40° C.)+ΔT2 (1° C.), and the controller 100 returns Yes in S26. to decide. Hot water supply set temperature Ta+ΔT2 is an example of the second reference temperature. The second reference temperature is a temperature higher than hot water supply set temperature Ta by ΔT2. The second reference temperature is lower than the first reference temperature.

In subsequent S27, the controller 100 calculates the first boiling temperature Tw1 of the next day (August 2). Specifically, the first boiling temperature Tw1 of the next day=the first boiling temperature Tw1 of the previous day+|the first hot water storage temperature Tb1-(the hot water supply set temperature Ta+ΔT2)| of the previous day. That is, the temperature obtained by adding the absolute value of the difference between the first hot water storage temperature Tb1 of the previous day and the second reference temperature (hot water supply set temperature Ta+ΔT2) to the first boiling temperature Tw1 of the previous day is set as the first boiling temperature Tw1 of the next day. .. Therefore, the first boiling temperature Tw1 of the next day is higher than the first boiling temperature Tw1 of the previous day.

On the other hand, in S28 after determining No in S26, the controller 100 sets the first boiling temperature Tw1 of the next day (August 2) to the same temperature as the first boiling temperature Tw1 of the previous day (August 1). And Therefore, the first boiling temperature Tw1 does not change.

In S29, the controller 100 permits the first boiling operation. When the controller 100 permits the first boiling operation, the first boiling operation is started. As described above, when the current time is the first boiling time (18:00) and the amount of hot water stored in the tank 10 is equal to or less than the predetermined amount (30 L) of hot water, the first boiling operation is started. It Further, when the boiling operation is already being executed, the boiling operation is switched to the first boiling operation.

When executing the first boiling operation on the next day (August 2), the controller 100 executes the first boiling operation based on the first boiling temperature Tw1 of the next day calculated as described above. The controller 100 executes the first boiling operation so that the warm water in the tank 10 reaches the calculated first boiling temperature Tw1 of the next day. The heat pump 50 heats the water in the tank 10 to the first boiling temperature Tw1 of the next day. The hot water boiled by the heat pump 50 is stored in the tank 10. The hot water having the first boiling temperature Tw1 of the next day is stored in the tank 10, and the amount of hot water stored in the tank 10 increases.

Then, in S30, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 100 L or more. When the amount of hot water stored in the tank 10 is 100 L or more, the controller 100 determines Yes in S30 and proceeds to S31. On the other hand, when the amount of hot water stored in the tank 10 is not 100 L or more (less than 100 L), the controller 100 determines No in S30 and stands by. The determination as to whether or not the amount of hot water stored in the tank 10 is 100 L or more can be made based on the temperature measured by the thermistor 24 provided on the upstream side of the heat pump 50. When the temperature measured by the thermistor 24 is equal to or higher than a predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is 100 L or more. The predetermined temperature serving as a criterion for the determination is, for example, the first boiling temperature of the next day-(minus) 5°C.

In subsequent S31, the controller 100 ends the first boiling operation. As described above, the first boiling operation on the next day is executed.

The first boiling operation has been described above. As is clear from the above description, the hot water supply system 2 includes the heat pump 50 that absorbs heat from the outside air to boil water, the tank 10 that stores the hot water boiled by the heat pump 50, and the hot water stored in the tank 10. The controller 100 is provided with a thermistor 11 for measuring the temperature, a supply path 40 for supplying the hot water in the tank 10 to the hot water use point, a remote controller 104 capable of setting the hot water supply set temperature Ta at the hot water use point. The controller 100 can execute a first boiling operation in which the water in the tank 10 is boiled to the first boiling temperature Tw1 by the heat pump 50 at a predetermined first boiling time. Further, the controller 100 sets the first hot water storage temperature Tb1 which is the temperature of the hot water in the tank 10 when the hot water storage amount in the tank 10 becomes less than a predetermined hot water storage amount after the first boiling operation is performed, to the thermistor. Measure at 11. After that, if the measured first hot water storage temperature Tb1 is higher than the first reference temperature (Ta+ΔT1) higher than the hot water supply set temperature Ta, the controller 100 lowers the first boiling temperature Tw1 of the next day. Specifically, the controller 100 sets the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature Tb1 and the first reference temperature (Ta+ΔT1) from the first boiling temperature Tw1 as the first boiling temperature Tw1 of the next day. If the measured first hot water storage temperature Tb1 is lower than the second reference temperature (Ta+ΔT2) that is higher than the hot water supply set temperature Ta and lower than the first reference temperature, the controller 100 raises the first boiling temperature Tw1 of the next day. Specifically, the controller 100 sets the temperature obtained by adding the absolute value of the difference between the first hot water storage temperature Tb1 and the second reference temperature (Ta+ΔT2) to the first boiling temperature Tw1 as the first boiling temperature Tw1 of the next day. Then, the controller 100 executes the first boiling operation of the next day at the calculated first boiling temperature Tw1 of the next day. That is, the controller 100 lowers or raises the first boiling temperature Tw1 of the next day and executes the first boiling operation of the next day.

According to such a configuration, the temperature of the hot water remaining in the tank 10 (first hot water storage temperature Tb1) is higher than the first reference temperature (Ta+ΔT1) immediately before the hot water boiled in the first boiling operation is used up. In the case, the first boiling temperature Tw1 of the next day is lowered. As a result, on the next day, the first boiling temperature Tw1 is lowered while maintaining the temperature of the hot water remaining in the tank 10 at or above the hot water supply set temperature Ta immediately before the hot water boiled in the first boiling operation is used up. can do. In this way, when the first hot water storage temperature Tb1 is high, the first boiling temperature Tw1 of the next day is lowered in order to lower the first hot water storage temperature Tb1 of the next day, so the first boiling when executing the first boiling operation is performed. COP can be raised by lowering the raising temperature Tw1. This is because the hot water supply system 2 can increase the COP by executing the boiling operation at the lowest possible temperature.

If the temperature of the hot water remaining in the tank 10 (first hot water storage temperature Tb1) is lower than the second reference temperature (Ta+ΔT2) immediately before the hot water boiled in the first boiling operation is used up, the Increase the boiling temperature Tw1. This makes it possible to reliably prevent the temperature of the hot water remaining in the tank 10 from falling below the hot water supply set temperature Ta immediately before the hot water boiled in the first boiling operation is used up on the next day. As described above, when the first hot water storage temperature Tb1 is low, the first hot water storage temperature Tb1 of the next day can be increased. Therefore, when the hot water in the tank 10 is supplied to the hot water use location, the hot water having a temperature lower than the hot water supply set temperature Ta is supplied. Can be suppressed from being supplied to the hot water use location.

Further, in the above configuration, when lowering the first boiling temperature Tw1 of the next day, the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature Tb1 and the first reference temperature (Ta+ΔT1) from the first boiling temperature Tw1 is used. The first boiling temperature Tw1 of the next day is set. This can prevent the first boiling temperature Tw1 of the next day from becoming too low. As a result, it is possible to prevent the temperature of the hot water remaining in the tank 10 (the first hot water storage temperature Tb1 of the next day) from becoming too low immediately before the hot water boiled in the first boiling operation of the next day is used up. On the other hand, in the above configuration, when raising the first boiling temperature Tw1 of the next day, the temperature obtained by adding the absolute value of the difference between the first hot water storage temperature Tb1 and the second reference temperature (Ta+ΔT2) to the first boiling temperature Tw1. The first boiling temperature Tw1 of the next day is set. This can prevent the first boiling temperature Tw1 of the next day from becoming too high. As a result, it is possible to prevent the first hot water storage temperature Tb1 of the next day from becoming too high. Since it is possible to prevent the first hot water storage temperature Tb1 of the next day from becoming too low and too high, the first hot water storage temperature Tb1 of the next day can be accurately brought close to the temperature close to the hot water supply set temperature Ta.

The hot water supply system 2 further includes a burner heating device 60 that heats the hot water supplied from the tank 10 to the hot water use location by burning fuel (for example, gas).

When the heating source of the hot water is only the heat pump 50, if the temperature of the hot water in the tank 10 becomes lower than the hot water supply set temperature Ta, hot water supply at the hot water supply set temperature Ta becomes impossible. For this reason, in the hot water supply system in which the heating source of the hot water is only the heat pump 50, the first reference temperature and the second reference temperature are set to be high and the boiling temperature in the boiling operation is maintained at a somewhat high temperature. You need to leave it. In contrast to this, when the burner heating device 60 is provided as the heating source of the hot water in addition to the heat pump 50 as in the hot water supply system 2 described above, the temperature of the hot water in the tank 10 is temporarily lower than the hot water supply set temperature Ta. Even if the temperature becomes low, hot water can be supplied at the hot water supply set temperature Ta by heating the hot water using the burner heating device 60. Therefore, according to the hot water supply system 2 described above, the first reference temperature and the second reference temperature can be set to lower temperatures, and the boiling temperature in the boiling operation can be set to a lower temperature. Therefore, COP in the boiling operation can be further increased.

(Second boiling operation)
Next, the control process regarding the second boiling operation will be described. To explain this, first, it is assumed that the user operates the remote controller 104 to set the hot water supply set temperature Ta at the hot water use location to 40° C. Further, as shown in FIG. 6, it is assumed that hot water is stored in the tank 10 at a certain time (for example, 22:00) on a certain day (for example, August 1st). The hot water boiled by the heat pump 50 is stored in the tank 10. It is assumed that the amount of hot water stored in the tank 10 at 22:00 is 30 L (liter) or less.

In this situation, as shown in FIG. 7, in S39, the controller 100 determines whether or not the current time is the second boiling time. The second boiling time is set by a learning process based on the past boiling time, and is 22:00, for example. The second boiling time (22:00) is a time after the first boiling time (18:00) in the first boiling operation described above. The second boiling time is the last boiling time of the day. When the current time is the second boiling time, the controller 100 determines Yes in S39 and proceeds to S40. On the other hand, if the current time is not the second boiling time, the controller 100 determines No in S39 and stands by.

In subsequent S40, the controller 100 determines whether or not the boiling operation of boiling the water in the tank 10 by the heat pump 50 is being executed. When the boiling operation is being executed, the controller 100 determines Yes in S40, skips S41, and proceeds to S42. On the other hand, when the boiling operation is not being executed, the controller 100 determines No in S40 and proceeds to S41.

In subsequent S41, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 30 L or less. When the amount of hot water stored in the tank 10 is 30 L or less, the controller 100 determines Yes in S41 and proceeds to S42. On the other hand, when the amount of hot water stored in the tank 10 is not 30 L or less (more than 30 L), the controller 100 determines No in S41 and stands by. Whether or not the amount of hot water stored in the tank 10 is 30 L or less can be determined based on the measured temperature of the thermistor 16 attached to the 30 L position of the tank 10. When the measured temperature of the thermistor 16 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 30 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S42, the controller 100 permits the second boiling operation. When the controller 100 permits the second boiling operation, the second boiling operation is started. As described above, when the current time is the second boiling time (22:00) and the amount of hot water stored in the tank 10 is equal to or less than the predetermined amount (30 L) of hot water, the second boiling operation is started. It In addition, when the boiling operation is already being executed, the boiling operation is switched to the second boiling operation. When the second boiling operation is started, the water in the tank 10 is boiled by the heat pump 50. The hot water boiled by the heat pump 50 is stored in the tank 10. Therefore, as shown in FIG. 6, the amount of hot water stored in the tank 10 increases after the second boiling time (22:00). The second boiling operation is performed after the above-described first boiling operation. The second boiling operation is the last boiling operation of the day.

When executing the second boiling operation, the controller 100 executes the second boiling operation so that the hot water in the tank 10 reaches the second boiling temperature Tw2. The second boiling temperature Tw2 is initially set and is, for example, 45°C. Alternatively, the second boiling temperature Tw2 may be set by a learning process based on the past boiling temperature. The heat pump 50 heats the water in the tank 10 to the second boiling temperature Tw2. Hot water having the second boiling temperature Tw2 is stored in the tank 10.

In subsequent S43, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 100 L or more. When the amount of hot water stored in the tank 10 is 100 L or more, the controller 100 determines Yes in S43 and proceeds to S44. On the other hand, when the amount of hot water stored in the tank 10 is not 100 L or more (less than 100 L), the controller 100 determines No in S43 and stands by. The determination as to whether or not the amount of hot water stored in the tank 10 is 100 L or more can be made based on the temperature measured by the thermistor 24 provided on the upstream side of the heat pump 50. When the temperature measured by the thermistor 24 is equal to or higher than a predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is 100 L or more. The predetermined temperature serving as a criterion for determination is, for example, the second boiling temperature −(minus) 5° C.

In subsequent S44, the controller 100 ends the second boiling operation. For example, as shown in FIG. 6, the hot water storage amount in the tank 10 becomes 100 L or more at 23:00, and the controller 100 ends the second boiling operation based on that.

When the hot water supply operation is executed after the second boiling operation is completed, the hot water in the tank 10 is supplied from the tank 10 to the hot water use location, and the amount of hot water stored in the tank 10 decreases. For example, the amount of hot water stored in the tank 10 decreases as hot water is used for brushing teeth and washing the face.

As shown in FIG. 7, in subsequent S45, controller 100 determines whether or not the last hot water supply operation of the day has been executed. When the last hot water supply operation of the day is executed, the controller 100 determines Yes in S45 and proceeds to S46. On the other hand, if the last hot water supply operation of the day is not executed, the controller 100 determines No in S45 and stands by. Whether or not the last hot water supply operation of the day has been executed is determined by, for example, storing the time when the hot water supply operation of that day (August 1st) is executed in the memory 102 to determine whether that day (August 1st) Can be judged ex post facto after. When the last hot water supply operation of the day is executed, the amount of hot water stored in the tank 10 does not decrease. For example, if the last hot water supply operation of the day is executed at 23:50 on that day (August 1), as shown in FIG. 6, the hot water storage amount in the tank 10 after 23:50 becomes constant. Become.

In subsequent S46, the controller 100 measures the second hot water storage temperature Tb2 which is the temperature of the hot water in the tank 10. The second hot water storage temperature Tb2 is measured by the thermistor 11 attached to the upper portion of the tank 10. The measured temperature of the thermistor 11 is transmitted to the controller 100, and the controller 100 receives it. Second hot water storage temperature Tb2 is the temperature of the hot water in tank 10 when the last hot water supply operation of the day is executed. That is, the second hot water storage temperature Tb2 is the temperature of the hot water in the tank 10 when the hot water in the tank was supplied to the hot water utilization point at the end of the day. The second hot water storage temperature Tb2 is the temperature of the hot water remaining in the tank 10 at the end of the day after boiling in the second boiling operation.

As shown in FIG. 8, the temperature of the hot water in the tank 10 is the second boiling temperature Tw2 (for example, 45° C.) at 23:00 immediately after the completion of the second boiling operation. After that, as time passes, the temperature of the hot water in the tank 10 decreases due to natural heat dissipation. Therefore, when the last hot water supply operation of the day is performed at 23:50, the temperature of the hot water in the tank 10 is lower than the second boiling temperature Tw2. That is, the second hot water storage temperature Tb2 measured by the thermistor 11 is lower than the second boiling temperature Tw2. The second hot water storage temperature Tb2 varies depending on how the temperature of the hot water in the tank 10 decreases. The second hot water storage temperature Tb2 is, for example, 43° C. or 40° C.

As shown in FIG. 7, in subsequent S47, controller 100 stores measured second hot water storage temperature Tb2 in memory 102. After that, the controller 100 ends the process relating to the second boiling operation on that day (August 1). The second hot water storage temperature Tb2 on that day (August 1) is used to calculate the second boiling temperature Tw2 in the second boiling operation on the next day (August 2).

Next, the operation on the next day (August 2) will be described. Also on the next day (August 2), first, similarly to the previous day (August 1), it is assumed that the hot water supply set temperature Ta at the hot water use location is set to 40°C. Further, it is assumed that the hot water storage amount in the tank 10 at a certain time (22:00) is 30 L (liter) or less.

In this situation, as shown in FIG. 9A, in S49, the controller 100 determines whether or not the current time is the second boiling time. The second boiling time is set by a learning process based on the past boiling time, and is 22:00, for example. When the current time is the second boiling time, the controller 100 determines Yes in S49 and proceeds to S50. On the other hand, if the current time is not the second boiling time, the controller 100 determines No in S49 and waits.

In subsequent S50, the controller 100 determines whether or not the boiling operation of boiling the water in the tank 10 by the heat pump 50 is being executed. If the boiling operation is being executed, the controller 100 determines Yes in S50, skips S51, and proceeds to S52. On the other hand, when the boiling operation is not being executed, the controller 100 determines No in S50 and proceeds to S51.

In subsequent S51, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 30 L or less. When the amount of hot water stored in the tank 10 is 30 L or less, the controller 100 determines Yes in S51 and proceeds to S52. On the other hand, when the amount of hot water stored in the tank 10 is not 30 L or less (more than 30 L), the controller 100 determines No in S51 and stands by. Whether or not the amount of hot water stored in the tank 10 is 30 L or less can be determined based on the measured temperature of the thermistor 16 attached to the 30 L position of the tank 10. When the measured temperature of the thermistor 16 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 30 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S52, controller 100 acquires second hot water storage temperature Tb2 after executing the second boiling operation on the previous day (August 1). The second hot water storage temperature Tb2 of the previous day is stored in the memory 102.

In subsequent S53, the controller 100 acquires the second boiling temperature Tw2 when the second boiling operation on the previous day (August 1) was executed. The second boiling temperature Tw2 of the previous day is stored in the memory 102.

As shown in FIG. 9B, in subsequent S54, controller 100 determines whether or not second hot water storage temperature Tb2 of the previous day is higher than hot water supply set temperature Ta+ΔT3. ΔT3 is a preset temperature, for example, 2°C. If the second hot water storage temperature Tb2 of the previous day is higher than the hot water supply set temperature Ta+ΔT3, the controller 100 determines Yes in S54 and proceeds to S55. For example, when the second hot water storage temperature Tb2 of the previous day is 43° C., the second hot water storage temperature Tb2 (43° C.)>hot water supply set temperature Ta (40° C.)+ΔT3 (2° C.), and the controller 100 returns Yes in S54. to decide. Hot water supply set temperature Ta+ΔT3 is an example of a third reference temperature. The third reference temperature is a temperature higher than the hot water supply set temperature Ta by ΔT3.

In subsequent S55, the controller 100 calculates the second boiling temperature Tw2 of the next day (August 2). Specifically, the second boiling temperature Tw2 of the next day=the second boiling temperature Tw2 of the previous day−|the second hot water storage temperature Tb2−(the hot water supply set temperature Ta+ΔT3)| of the previous day. That is, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature Tb2 of the previous day and the second reference temperature (hot water supply set temperature Ta+ΔT3) from the second boiling temperature Tw2 of the previous day is set as the second boiling temperature Tw2 of the next day. .. Therefore, the second boiling temperature Tw2 of the next day is lower than the second boiling temperature Tw2 of the previous day.

On the other hand, in S56 after determining No in S54, controller 100 determines whether or not second hot water storage temperature Tb2 of the previous day is lower than hot water supply set temperature Ta+ΔT4. ΔT4 is a preset temperature, for example, 1°C. ΔT4 is a temperature lower than ΔT3 (small value). When the second hot water storage temperature Tb2 of the previous day is lower than the hot water supply set temperature Ta+ΔT4, the controller 100 determines Yes in S56 and proceeds to S57. For example, when the second hot water storage temperature Tb2 of the previous day is 40° C., the second hot water storage temperature Tb2 (40° C.)<hot water supply set temperature Ta (40° C.)+ΔT4 (1° C.), and the controller 100 returns Yes in S56. to decide. Hot water supply set temperature Ta+ΔT4 is an example of a fourth reference temperature. The fourth reference temperature is a temperature higher than hot water supply set temperature Ta by ΔT4. The fourth reference temperature is lower than the third reference temperature.

In subsequent S57, the controller 100 calculates the second boiling temperature Tw2 of the next day (August 2). Specifically, the second boiling temperature Tw2 of the next day=the second boiling temperature Tw2 of the previous day+|the second hot water storage temperature Tb2-(the hot water supply set temperature Ta+ΔT4)| of the previous day. That is, the temperature obtained by adding the absolute value of the difference between the second hot water storage temperature Tb2 of the previous day and the fourth reference temperature (hot water supply set temperature Ta+ΔT4) to the second boiling temperature Tw2 of the previous day is set as the second boiling temperature Tw2 of the next day. .. Therefore, the second boiling temperature Tw2 of the next day is higher than the second boiling temperature Tw2 of the previous day.

On the other hand, in S58 after determining No in S56, the controller 100 sets the second boiling temperature Tw2 of the next day (August 2) to the same temperature as the second boiling temperature Tw2 of the previous day (August 1). And Therefore, the second boiling temperature Tw2 does not change.

In subsequent S59, the controller 100 permits the second boiling operation. When the controller 100 permits the second boiling operation, the second boiling operation is started. As described above, when the current time is the second boiling time (22:00) and the amount of hot water stored in the tank 10 is equal to or less than the predetermined amount (30 L) of hot water, the second boiling operation is started. It In addition, when the boiling operation is already being executed, the boiling operation is switched to the second boiling operation.

When executing the second boiling operation on the next day (August 2), the controller 100 executes the second boiling operation based on the second boiling temperature Tw2 of the next day calculated as described above. The controller 100 executes the second boiling operation so that the hot water in the tank 10 reaches the calculated second boiling temperature Tw2 of the next day. The heat pump 50 heats the water in the tank 10 to the second boiling temperature Tw2 of the next day. The hot water boiled by the heat pump 50 is stored in the tank 10. The hot water having the second boiling temperature Tw2 of the next day is stored in the tank 10, and the amount of hot water stored in the tank 10 increases.

Then, in S60, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 100 L or more. When the amount of hot water stored in the tank 10 is 100 L or more, the controller 100 determines Yes in S60 and proceeds to S61. On the other hand, when the amount of hot water stored in the tank 10 is not 100 L or more (less than 100 L), the controller 100 determines No in S60 and stands by. The determination as to whether or not the amount of hot water stored in the tank 10 is 100 L or more can be made based on the temperature measured by the thermistor 24 provided on the upstream side of the heat pump 50. When the temperature measured by the thermistor 24 is equal to or higher than a predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is 100 L or more. The predetermined temperature serving as a criterion for determination is, for example, the second boiling temperature of the next day−(minus) 5° C.

In subsequent S61, the controller 100 ends the second boiling operation. As described above, the second boiling operation on the next day is executed.

The second boiling operation has been described above. As is clear from the above description, the hot water supply system 2 includes the heat pump 50 that absorbs heat from the outside air to boil water, the tank 10 that stores the hot water boiled by the heat pump 50, and the hot water stored in the tank 10. The controller 100 is provided with a thermistor 11 for measuring the temperature, a supply path 40 for supplying the hot water in the tank 10 to the hot water use point, a remote controller 104 capable of setting the hot water supply set temperature Ta at the hot water use point. The controller 100 can execute the second boiling operation in which the water in the tank 10 is boiled to the second boiling temperature Tw2 by the heat pump 50 at the second boiling time which is the last boiling time of the day. Further, the controller 100 measures the temperature of the hot water in the tank 10 with the thermistor 11 when the final hot water supply operation of the day is executed after the second boiling operation is executed. That is, the controller 100 sets the second hot water storage temperature Tb2, which is the temperature of the hot water in the tank 10 when the hot water in the tank 10 is supplied to the hot water use location at the end of the day after executing the second boiling operation. It is measured by the thermistor 11. After that, when the measured second hot water storage temperature Tb2 is higher than the third reference temperature (Ta+ΔT3) higher than the hot water supply set temperature Ta, the controller 100 lowers the second boiling temperature Tw2 of the next day. Specifically, the controller 100 sets the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature Tb2 and the third reference temperature (Ta+ΔT3) from the second boiling temperature Tw2 as the second boiling temperature Tw2 of the next day. When the measured second hot water storage temperature Tb2 is lower than the fourth reference temperature (Ta+ΔT4) which is higher than the hot water supply set temperature Ta and lower than the third reference temperature, controller 100 raises second boiling temperature Tw2 of the next day. Specifically, the controller 100 sets the temperature obtained by adding the absolute value of the difference between the second hot water storage temperature Tb2 and the fourth reference temperature (Ta+ΔT4) to the second boiling temperature Tw2 as the second boiling temperature Tw2 of the next day. Then, the controller 100 executes the second boiling operation of the next day at the calculated second boiling temperature Tw2 of the next day. That is, the controller 100 lowers or raises the second boiling temperature Tw2 of the next day and executes the second boiling operation of the next day.

According to such a configuration, after boiling in the second boiling operation, the temperature of the hot water (second hot water storage temperature Tb2) remaining in the tank 10 at the end of the day is the third reference temperature (Ta+ΔT3). If it is higher, the second boiling temperature Tw2 of the next day is lowered. As a result, on the next day, the second boiling temperature Tw2 can be lowered while maintaining the temperature of the hot water remaining in the tank 10 at the end of the day at the hot water supply set temperature Ta or higher. In this way, when the second hot water storage temperature Tb2 is high, the second boiling temperature Tw2 of the next day is lowered in order to lower the second hot water storage temperature Tb2 of the next day, so the second boiling when executing the second boiling operation is performed. COP can be raised by lowering the raising temperature Tw2.

Further, if the temperature of the hot water remaining in the tank 10 (second hot water storage temperature Tb2) is lower than the fourth reference temperature (Ta+ΔT4) at the end of the day after boiling in the second boiling operation, the next day The second boiling temperature Tw2 of is increased. This can surely prevent the temperature of the hot water remaining in the tank 10 from falling below the hot water supply set temperature Ta at the end of the next day. Thus, when the second hot water storage temperature Tb2 is low, the second hot water storage temperature Tb2 of the next day can be raised. Can be suppressed from being supplied to the hot water use location.

Further, in the above configuration, when lowering the second boiling temperature Tw2 of the next day, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature Tb2 and the third reference temperature (Ta+ΔT3) from the second boiling temperature Tw2 is used. The second boiling temperature Tw2 of the next day is set. This can prevent the second boiling temperature Tw2 of the next day from becoming too low. As a result, it is possible to prevent the temperature of the hot water remaining in the tank 10 (the second hot water storage temperature Tb2 of the next day) from becoming too low at the end of the next day. On the other hand, in the above configuration, when raising the second boiling temperature Tw2 of the next day, the temperature obtained by adding the absolute value of the difference between the second hot water storage temperature Tb2 and the fourth reference temperature (Ta+ΔT4) to the second boiling temperature Tw2. The second boiling temperature Tw2 of the next day is set. This can prevent the second boiling temperature Tw2 of the next day from becoming too high. As a result, it is possible to prevent the second hot water storage temperature Tb2 of the next day from becoming too high. Since it is possible to prevent the second hot water storage temperature Tb2 of the next day from becoming too low and too high, the second hot water storage temperature Tb2 of the next day can be accurately brought close to the hot water supply set temperature Ta.

Further, the hot water supply system 2 includes a burner heating device 60 that heats the hot water supplied from the tank 10 to the hot water use location by burning fuel (for example, gas). According to such a configuration, hot water can be supplied at the hot water supply set temperature Ta by heating the hot water using the burner heating device 60, as in the case of the first boiling operation described above. Therefore, the third reference temperature and the fourth reference temperature can be set to lower temperatures, and the boiling temperature in the boiling operation can be set to a lower temperature. Therefore, COP in the boiling operation can be further increased.

(3rd boiling operation)
Next, a control process regarding the third boiling operation will be described. In order to explain this, first, it is assumed that the user operates the remote controller 104 to set the hot water supply set temperature Ta at the hot water use location to 40°C. Further, as shown in FIG. 10, it is assumed that hot water is stored in the tank 10 at a certain time (for example, 20:30) on a certain day (for example, August 1). The hot water boiled by the heat pump 50 is stored in the tank 10. It is assumed that the amount of hot water stored in the tank 10 at 20:30 is 30 L (liter) or less.

In this situation, as shown in FIG. 11, in S69, the controller 100 determines whether or not the current time is the third boiling time. The third boiling time is set by a learning process based on the past boiling time, and is, for example, 20:30. The third boiling time (20:30) is the first boiling time (18:00) in the first boiling operation and the second boiling time (22:00) in the second boiling operation. It is the time between. When the current time is the third boiling time, the controller 100 determines Yes in S69 and proceeds to S70. On the other hand, if the current time is not the third boiling time, the controller 100 determines No in S69 and waits.

In subsequent S70, the controller 100 determines whether or not the boiling operation for boiling the water in the tank 10 by the heat pump 50 is being executed. When the boiling operation is being executed, the controller 100 determines Yes in S70, skips S71, and proceeds to S72. On the other hand, when the boiling operation is not being executed, the controller 100 determines No in S70 and proceeds to S71.

In subsequent S71, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 30 L or less. When the amount of hot water stored in the tank 10 is 30 L or less, the controller 100 determines Yes in S71 and proceeds to S72. On the other hand, when the amount of hot water stored in the tank 10 is not 30 L or less (more than 30 L), the controller 100 determines No in S71 and stands by. Whether or not the amount of hot water stored in the tank 10 is 30 L or less can be determined based on the measured temperature of the thermistor 16 attached to the 30 L position of the tank 10. When the measured temperature of the thermistor 16 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 30 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S72, the controller 100 permits the third boiling operation. When the controller 100 permits the third boiling operation, the third boiling operation is started. As described above, when the current time is the third boiling time (20:30) and the amount of hot water stored in the tank 10 is equal to or less than the predetermined amount (30 L) of hot water, the third boiling operation is started. It When the boiling operation is already being executed, the boiling operation is switched to the third boiling operation. When the third boiling operation is started, the water in the tank 10 is boiled by the heat pump 50. The hot water boiled by the heat pump 50 is stored in the tank 10. Therefore, as shown in FIG. 10, the amount of hot water stored in the tank 10 increases after the third boiling time (20:30). The third boiling operation is executed between the first boiling operation and the second boiling operation. The third boiling operation is executed between the first boiling time and the second boiling time.

When executing the third boiling operation, the controller 100 executes the third boiling operation so that the hot water in the tank 10 reaches the third boiling temperature Tw3. The third boiling temperature Tw3 is initially set and is, for example, 45°C. Alternatively, the third boiling temperature Tw3 may be set by a learning process based on the past boiling temperature. The heat pump 50 heats the water in the tank 10 to the third boiling temperature Tw3. Hot water having the third boiling temperature Tw3 is stored in the tank 10.

As shown in FIG. 11, in subsequent S73, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 100 L or more. When the amount of hot water stored in the tank 10 is 100 L or more, the controller 100 determines Yes in S73 and proceeds to S74. On the other hand, when the amount of hot water stored in the tank 10 is not 100 L or more (less than 100 L), the controller 100 determines No in S73 and stands by. The determination as to whether or not the amount of hot water stored in the tank 10 is 100 L or more can be made based on the temperature measured by the thermistor 24 provided on the upstream side of the heat pump 50. When the temperature measured by the thermistor 24 is equal to or higher than a predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is 100 L or more. The predetermined temperature serving as a criterion for determination is, for example, the third boiling temperature-(minus) 5°C.

In subsequent S74, the controller 100 ends the third boiling operation. For example, as shown in FIG. 10, the stored amount of hot water in the tank 10 becomes 100 L or more at 21:30, and the controller 100 ends the third boiling operation based on that. When the hot water supply operation is executed after the third boiling operation is completed, the hot water in the tank 10 is supplied from the tank 10 to the hot water utilization point, and the amount of hot water stored in the tank 10 decreases. After that, the controller 100 ends the process related to the third boiling operation on that day (August 1st).

Next, the operation on the next day (August 2) will be described. Also on the next day (August 2), first, similarly to the previous day (August 1), it is assumed that the hot water supply set temperature Ta at the hot water use location is set to 40°C. Further, it is assumed that the hot water storage amount in the tank 10 at a certain time (20:30) is 30 L (liter) or less.

In this situation, as shown in FIG. 12, in S79, the controller 100 determines whether or not the current time is the third boiling time. The third boiling time is set by a learning process based on the past boiling time, and is, for example, 20:30. When the current time is the third boiling time, the controller 100 determines Yes in S79 and proceeds to S80. On the other hand, if the current time is not the third boiling time, the controller 100 determines No in S79 and stands by.

In subsequent S80, the controller 100 determines whether or not the boiling operation for boiling the water in the tank 10 by the heat pump 50 is being executed. When the boiling operation is being executed, the controller 100 determines Yes in S80, skips S81, and proceeds to S82. On the other hand, when the boiling operation is not being executed, the controller 100 determines No in S80 and proceeds to S81.

In subsequent S81, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 30 L or less. When the amount of hot water stored in the tank 10 is 30 L or less, the controller 100 determines Yes in S81 and proceeds to S82. On the other hand, when the amount of hot water stored in the tank 10 is not 30 L or less (more than 30 L), the controller 100 determines No in S81 and stands by. Whether or not the amount of hot water stored in the tank 10 is 30 L or less can be determined based on the measured temperature of the thermistor 16 attached to the 30 L position of the tank 10. When the measured temperature of the thermistor 16 is equal to or lower than the predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is equal to or lower than 30 L. The predetermined temperature serving as a criterion for determination is, for example, hot water supply set temperature Ta−(minus) 5° C.

In subsequent S82, the controller 100 causes the first boiling temperature Tw1 in the first boiling operation on the next day (August 2) and the second boiling temperature Tw2 in the second boiling operation on the next day (August 2). To get. As described in the first boiling operation, the first boiling temperature Tw1 of the next day (August 2) is calculated based on the first hot water storage temperature Tb1 of the previous day (August 1). Further, as described in the second boiling operation, the second boiling temperature Tw2 of the next day (August 2) is calculated based on the second hot water storage temperature Tb2 of the previous day (August 1). ..

In subsequent S83, the controller 100 determines whether or not the first boiling temperature Tw1 of the next day (August 2) is equal to or higher than the second boiling temperature Tw2+3°C of the next day (August 2). If the first boiling temperature Tw1 of the next day is equal to or higher than the second boiling temperature Tw2+3° C. of the next day, the controller 100 determines Yes in S83 and proceeds to S84. On the other hand, if the first boiling temperature Tw1 of the next day is not equal to or higher than the second boiling temperature Tw2+3° C. of the next day (Tw1 is lower than Tw2+3° C.), the controller 100 determines No in S83 and proceeds to S85.

In S84 after determining Yes in S83, the controller 100 calculates the third boiling temperature Tw3 on the next day (August 2). Specifically, the third boiling temperature Tw3 of the next day=the first boiling temperature Tw1-ΔTx of the next day. That is, the temperature obtained by subtracting the predetermined temperature ΔTx from the first boiling temperature Tw1 of the next day is set as the third boiling temperature Tw3 of the next day. The predetermined temperature ΔTx is not particularly limited. Further, the predetermined temperature ΔTx may change over time. For example, ΔTx may be increased by 1° C. every 20 minutes from the time when the first hot water storage temperature Tb1 is measured. Further, ΔTx<the first boiling temperature Tw of the next day 1−the second boiling temperature Tw2 of the next day.

On the other hand, in S85 after determining No in S83, the controller 100 sets the third boiling temperature Tw3 of the next day (August 2) to the same temperature as the second boiling temperature Tw2 of the next day. When the second boiling temperature Tw2 of the next day is higher than the first boiling temperature Tw1 of the next day, the third boiling temperature Tw3 of the next day also becomes higher than the first boiling temperature Tw1 of the next day. When the second boiling temperature Tw2 of the next day is lower than the first boiling temperature Tw1 of the next day, the third boiling temperature Tw3 of the next day also becomes lower than the first boiling temperature Tw1 of the next day.

In subsequent S86, the controller 100 permits the third boiling operation. When the controller 100 permits the third boiling operation, the third boiling operation is started. As described above, when the current time is the third boiling time (20:30) and the amount of hot water stored in the tank 10 is equal to or less than the predetermined amount (30 L) of hot water, the third boiling operation is started. It When the boiling operation is already being executed, the boiling operation is switched to the third boiling operation.

Then, in S87, the controller 100 determines whether or not the amount of hot water stored in the tank 10 is 100 L or more. When the amount of hot water stored in the tank 10 is 100 L or more, the controller 100 determines Yes in S87 and proceeds to S88. On the other hand, when the amount of hot water stored in the tank 10 is not 100 L or more (less than 100 L), the controller 100 determines No in S87 and stands by. The determination as to whether or not the amount of hot water stored in the tank 10 is 100 L or more can be made based on the temperature measured by the thermistor 24 provided on the upstream side of the heat pump 50. When the temperature measured by the thermistor 24 is equal to or higher than a predetermined temperature, it can be determined that the amount of hot water stored in the tank 10 is 100 L or more. The predetermined temperature serving as a criterion for determination is, for example, the third boiling temperature of the next day-(minus) 5°C.

In subsequent S88, the controller 100 ends the third boiling operation. As described above, the third boiling operation on the next day is executed.

The third boiling operation has been described above. As is clear from the above description, the hot water supply system 2 includes the heat pump 50 that absorbs heat from the outside air to boil water, the tank 10 that stores the hot water boiled by the heat pump 50, and the hot water stored in the tank 10. The controller 100 is provided with a thermistor 11 for measuring the temperature, a supply path 40 for supplying the hot water in the tank 10 to the hot water use point, a remote controller 104 capable of setting the hot water supply set temperature Ta at the hot water use point. The controller 100 has a first boiling operation in which the water in the tank 10 is boiled to the first boiling temperature Tw1 by the heat pump 50 at a predetermined first boiling time and a second boiling time that is the last boiling time of the day. The second boiling operation in which the water in the tank 10 is heated to the second boiling temperature Tw2 by the heat pump 50 at the raising time can be executed. The first boiling operation and the second boiling operation have been described above. Further, the controller 100 can execute the third boiling operation in which the water in the tank 10 is boiled to the third boiling temperature Tw3 by the heat pump 50 between the first boiling operation and the second boiling operation. The controller 100 sets the third boiling temperature Tw3 of the next day to the temperature of the first boiling temperature Tw1-ΔTx of the next day. Alternatively, the controller 100 sets the third boiling temperature Tw3 of the next day to the same temperature as the second boiling temperature Tw2 of the next day. That is, the third boiling temperature Tw3 of the next day is a temperature between the first boiling temperature Tw1 of the next day and the second boiling temperature Tw2 of the next day. The controller 100 sets the temperature between the first boiling temperature Tw1 of the next day and the second boiling temperature Tw2 of the next day to the third boiling of the next day between the first boiling operation of the next day and the second boiling operation of the next day. As the raising temperature Tw3, the third boiling operation of the next day is executed.

According to such a configuration, with respect to the first boiling operation on the next day, the first boiling temperature Tw1 is lowered as much as possible to increase the COP when the boiling operation is performed, and the temperature is lower than the hot water supply set temperature Ta. While it is possible to prevent hot water from being supplied to the hot water utilization point, with respect to the second boiling operation of the next day, while lowering the second boiling temperature Tw2 as much as possible and increasing the COP when executing the boiling operation, It is possible to prevent hot water having a temperature lower than the hot water supply set temperature Ta from being supplied to the hot water use location. Further, with respect to the first boiling operation on the next day, the first hot water storage temperature Tb1 on the next day can be accurately brought close to the temperature close to the hot water supply set temperature Ta. Further, regarding the second boiling operation on the next day, the second hot water storage temperature Tb2 on the next day can be accurately brought close to the temperature close to the hot water supply set temperature Ta.

Further, according to the above configuration, the third boiling temperature Tw3 in the third boiling operation performed between the first boiling operation and the second boiling operation is set to the first boiling temperature Tw1 and the second boiling temperature Tw3. The temperature is between the temperatures Tw2. If the third boiling temperature Tw3 is made extremely lower than the first boiling temperature Tw1 and the second boiling temperature Tw2, the temperature of the hot water remaining in the tank 10 during the third boiling operation Is higher than the third boiling temperature Tw3, and the temperature stratification in the tank 10 may be reversed. On the contrary, if the third boiling temperature Tw3 is made extremely higher than the first boiling temperature Tw1 and the second boiling temperature Tw2, the hot water remaining in the tank 10 during the second boiling operation is increased. Since the temperature is higher than the second boiling temperature Tw2, the temperature stratification in the tank 10 may be reversed. As described above, by setting the third boiling temperature Tw3 to a temperature between the first boiling temperature Tw1 and the second boiling temperature Tw2, the tank 10 can be operated during the third boiling operation and the second boiling operation. It is possible to prevent the temperature stratification therein from being reversed.

Although one embodiment has been described above, the specific mode is not limited to the above embodiment.

In the above embodiment, the first hot water storage temperature Tb1 of the previous day (August 1st) was used to calculate the first boiling temperature Tw1 of the next day (August 2nd), but the configuration is limited to this. Not a thing. In another example, in order to calculate the first boiling temperature Tw1 of the next day (August 2), the average value of the first hot water storage temperature Tb1 over several days until the previous day (August 1) may be used. Good.

Further, in the above embodiment, the second hot water storage temperature Tb2 of the previous day (August 1st) was used to calculate the second boiling temperature Tw2 of the next day (August 2nd), but the configuration is limited to this configuration. It is not something that will be done. In another example, in order to calculate the second boiling temperature Tw2 of the next day (August 2), the average value of the second hot water storage temperature Tb2 over several days until the previous day (August 1) may be used. Good.

Further, in the above embodiment, the hot water supply operation is started after the first boiling operation is finished, but the present invention is not limited to this configuration. In another embodiment, the hot water supply operation may be started before the end of the first boiling operation. Therefore, the hot water in the tank 10 may be supplied to the hot water use location before the amount of hot water stored in the tank 10 reaches 100 L or more.

Further, in the above-described embodiment, the third boiling operation is executed once between the first boiling operation and the second boiling operation, but the configuration is not limited to this. In another embodiment, the third boiling operation may be performed multiple times.

Further, in the above embodiment, the first hot water storage temperature Tb1 is measured in S16 when the hot water storage amount in the tank 10 is 12 L or less in S15, but the present invention is not limited to this configuration. In another embodiment, when the amount of hot water stored in the tank 10 is 30 L or less or 50 L or less in S15, the first hot water storage temperature Tb1 may be measured in S16. That is, the predetermined amount of stored hot water serving as a reference when measuring the first hot water storage temperature Tb1 is not particularly limited.

The predetermined hot water storage amount serving as a reference when measuring the first hot water storage temperature Tb1 may be set based on the past hot water storage amount. For example, among the hot water storage amounts on July 31, the day before August 1, the minimum hot water storage amount excluding the hot water outage condition can be set as the predetermined hot water storage amount. That is, the hot water storage amount when the hot water storage amount in the tank 10 becomes the smallest on a certain day in the past can be set as the predetermined hot water storage amount. It is also possible to measure the minimum amount of hot water storage excluding the hot water outage over the past several days, and set the average value thereof as the predetermined amount of hot water storage. Further, the hot water storage amount near the minimum hot water storage amount can be set as the predetermined hot water storage amount. The temperature of the hot water immediately before the hot water in the tank 10 is used up can be measured by setting the predetermined hot water storage amount, which is the reference when measuring the first hot water storage temperature Tb1, to a value as small as possible.

Further, the method for obtaining the amount of hot water stored in the tank 10 is not particularly limited. In another embodiment, the amount of hot water stored in the tank 10 can be calculated based on the measured temperatures of the thermistors attached to the tank 10. Specifically, as shown in FIG. 13, first, in S91, the controller 100 acquires the measured temperatures of the thermistors 12, 14, 16, and 18 attached to the positions of 6L, 12L, 30L, and 50L of the tank 10. ..

Subsequently, in S92, the controller 100 calculates the stored hot water amount in the tank 10 by linear approximation based on the measured temperatures of the thermistors 12, 14, 16, and 18. For example, when the measured temperature of the thermistor 12 attached to the 6L position of the tank 10 is 39°C and the measured temperature of the thermistor 14 attached to the 12L position of the tank 10 is 42°C, a linear approximation is performed. Thus, it is possible to calculate that the amount of hot water stored in the tank 10 at 40° C. or higher is 8 L.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in the present specification or the drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Further, the technique illustrated in the present specification or the drawings can simultaneously achieve a plurality of objects, and achieving the one object among them has technical utility.

2: Hot water supply system 10: Tank 11: Thermistor 12: Thermistor 14: Thermistor 16: Thermistor 18: Thermistor 20: Tank water circulation passage 22: Circulation pump 24: Thermistor 30: Water supply passage 30a: First introduction passage 30b: Second introduction passage 31: Tap water supply source 32: Thermistor 40: Supply path 42: Mixing valve 43: Thermistor 44: Thermistor 50: Heat pump 60: Burner heating device 100: Controller 102: Memory 104: Remote control

Claims (7)

A heat pump that absorbs heat from the outside air to boil water,
A tank for storing hot water boiled by the heat pump,
A temperature sensor for measuring the temperature of hot water stored in the tank,
A supply path for supplying the hot water in the tank to the hot water utilization point,
Setting means capable of setting the hot water supply set temperature at the hot water use point,
Equipped with control means,
The control means can execute a first boiling operation of boiling the water in the tank to a first boiling temperature by the heat pump at a predetermined first boiling time, and after performing the first boiling operation. The first hot water storage temperature, which is the temperature of the hot water in the tank when the hot water storage amount in the tank becomes less than a predetermined hot water storage amount, is measured by the temperature sensor, and the first hot water storage temperature is higher than the hot water supply set temperature. When the temperature is higher than the first reference temperature, the first boiling temperature on the next day is lowered, and when the first hot water storage temperature is higher than the hot water supply set temperature and lower than the first reference temperature, the first boiling temperature on the next day A hot water supply system that raises the raising temperature and executes the first boiling operation on the next day. When the first hot water storage temperature is higher than the hot water supply set temperature and higher than the first reference temperature, the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature and the first reference temperature from the first boiling temperature is the first boiling temperature of the next day. If the first hot water storage temperature is higher than the hot water supply set temperature and lower than the second reference temperature lower than the first reference temperature, the absolute value of the difference between the first hot water storage temperature and the second reference temperature is added to the first boiling temperature. The hot water supply system according to claim 1, wherein the first boiling operation of the next day is executed with the temperature thus set as the first boiling temperature of the next day. A heat pump that absorbs heat from the outside air to boil water,
A tank for storing hot water boiled by the heat pump,
A temperature sensor for measuring the temperature of hot water stored in the tank,
A supply path for supplying the hot water in the tank to the hot water utilization point,
Setting means capable of setting the hot water supply set temperature at the hot water use point,
Equipped with control means,
The control means is capable of executing a second boiling operation in which the water in the tank is boiled to a second boiling temperature by the heat pump at a second boiling time which is the last boiling time of the day. The second hot water temperature, which is the temperature of the hot water in the tank when the hot water in the tank is supplied to the hot water utilization point at the end of the day after performing the two boiling operation, is measured by the temperature sensor, If the second hot water storage temperature is higher than the third reference temperature higher than the hot water supply set temperature, the second boiling temperature on the next day is lowered to make the second hot water storage temperature higher than the hot water supply set temperature and lower than the third reference temperature. If it is lower, the hot water supply system that raises the second boiling temperature of the next day and executes the second boiling operation of the next day. When the second hot water storage temperature is higher than the hot water supply set temperature and higher than the third reference temperature, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature and the third reference temperature from the second boiling temperature is the second boiling of the next day. When the second hot water storage temperature is higher than the hot water supply set temperature and lower than the fourth reference temperature lower than the third reference temperature, the absolute value of the difference between the second hot water storage temperature and the fourth reference temperature is added to the second boiling temperature. The hot water supply system according to claim 3, wherein the second boiling temperature is set as the second boiling temperature of the next day, and the second boiling operation of the next day is executed. A heat pump that absorbs heat from the outside air to boil water,
A tank for storing hot water boiled by the heat pump,
A temperature sensor for measuring the temperature of hot water stored in the tank,
A supply path for supplying the hot water in the tank to the hot water utilization point,
Setting means capable of setting the hot water supply set temperature at the hot water use point,
Equipped with control means,
The control means comprises a first boiling operation in which the water in the tank is boiled to a first boiling temperature by the heat pump at a predetermined first boiling time, and a second boiling time which is the last boiling time of the day. The water in the tank is heated by the heat pump between the second boiling operation and the second boiling operation in which the water in the tank is heated to the second boiling temperature by the heat pump at the raising time. A third boiling operation of boiling to a third boiling temperature, and
The first hot water storage temperature, which is the temperature of the hot water in the tank when the hot water storage amount in the tank becomes less than a predetermined hot water storage amount after performing the first boiling operation, is measured by the temperature sensor, and 1 If the hot water storage temperature is higher than the first reference temperature which is higher than the hot water supply set temperature, the first boiling temperature on the next day is lowered so that the first hot water storage temperature is higher than the hot water supply set temperature and lower than the second reference temperature which is lower than the first reference temperature. If the temperature is low, raise the first boiling temperature of the next day and execute the first boiling operation of the next day,
The second hot water storage temperature, which is the temperature of the hot water in the tank when the hot water in the tank was supplied to the hot water utilization point at the end of the day after the second boiling operation was measured by the temperature sensor. If the second hot water storage temperature is higher than the third reference temperature which is higher than the hot water supply set temperature, the second boiling temperature on the next day is lowered to make the second hot water storage temperature higher than the hot water supply set temperature and lower than the third reference temperature. If the temperature is lower than the temperature, raise the second boiling temperature of the next day and execute the second boiling operation of the next day,
Between the first boiling operation of the next day and the second boiling operation of the next day, the temperature between the first boiling temperature of the next day and the second boiling temperature of the next day is set as the third boiling temperature of the next day and is set as the third boiling temperature of the next day. A hot water supply system that executes the third boiling operation. When the first hot water storage temperature is higher than the hot water supply set temperature and higher than the first reference temperature, the temperature obtained by subtracting the absolute value of the difference between the first hot water storage temperature and the first reference temperature from the first boiling temperature is the first boiling temperature of the next day. If the first hot water storage temperature is higher than the hot water supply set temperature and lower than the second reference temperature lower than the first reference temperature, the absolute value of the difference between the first hot water storage temperature and the second reference temperature is added to the first boiling temperature. As the first boiling temperature of the next day, the first boiling operation of the next day is executed,
When the second hot water storage temperature is higher than the hot water supply set temperature and higher than the third reference temperature, the temperature obtained by subtracting the absolute value of the difference between the second hot water storage temperature and the third reference temperature from the second boiling temperature is the second boiling of the next day. When the second hot water storage temperature is higher than the hot water supply set temperature and lower than the fourth reference temperature lower than the third reference temperature, the absolute value of the difference between the second hot water storage temperature and the fourth reference temperature is added to the second boiling temperature. The hot water supply system according to claim 5, wherein the second boiling temperature of the next day is used as the second boiling temperature of the next day, and the second boiling operation of the next day is executed. The hot water supply system according to any one of claims 1 to 6, further comprising an auxiliary heater that heats hot water supplied from the tank to the hot water use location by burning fuel.

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