JP2001227819A - Hot-water supply device utilizing solar energy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve ease of use and economy by efficient heat collection operation that is suited for a life pattern. SOLUTION: This hot-water supply device is provided with a heat-collecting device 17 comprising a heat collector 3, a heat exchanger 2, and a compressor 1, a water-circulating device 18 comprising a hot water storage tank 4, a circulation pump 5, and the heat exchanger 2, a temperature detection part 7 for detecting the temperature of the hot water storage tank 4, a heat collection device control part 20 for driving the heat-collecting device 17 to obtain a target temperature range, a clocking means 23 for clocking current time, an operation time zone storage part 24 for storing a time zone that is available for operation, and a heat collection operation start judgment part 22 for judging the operation start of the heat-collecting device 17 by the clocking means 17 and the operation time zone storage part 24. When an operation signal is outputted from the heat collection operation start judgment part 22, the operation of the heat-collecting device 17 is controlled based on the control signal of the heat collection device control part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar water heater that collects solar heat and atmospheric heat to supply hot water.

[0002]

2. Description of the Related Art As shown in FIG. 5, this type of conventional solar water heater uses a heat collecting circuit including a compressor 1, a heat exchanger 2, and a heat collector 3, a hot water tank 4, a circulation pump 5, The hot water supply circuit is constituted by the heat exchanger 2, and the amount of heat collected from both solar heat and atmospheric heat is absorbed by the hot water supply circuit through the heat exchanger 2, so that hot water at a predetermined temperature is stored in the hot water storage tank 4. ,
It is used as needed.

The heat collecting control of the hot water supply apparatus is performed by a sunshine sensor 6 provided near the heat collector 3, a hot water temperature sensor 7 provided in the hot water storage tank 4, a controller 8, and a remote controller 9. The operation of the heat collecting circuit was controlled by the illuminance detection output of the sunshine sensor 6.

An example of this control circuit will be described with reference to FIG. 6. A controller 8 comprises various arithmetic circuits 10 and a sunshine detection circuit 1
1, a remote control circuit 12, and a hot water temperature detection circuit 13, which open and close a contact 14. The compressor 1 and the circulation pump 5 are connected to the contact 14, and power is supplied through an operation switch 15.

[0005] The remote controller 9 has "automatic" and "manual".
An operation mode selection switch 16 for selecting any one of the above is provided.

Next, the control operation in the above-mentioned conventional configuration will be described. First, when the weather in summer is good, the operation switch is turned on and the operation mode is set to "automatic". At dawn, the sun rises and the outdoors become brighter. When it starts, the sunshine sensor 6 detects a set illuminance, for example, 500 Lx or more, and if the hot water temperature at this time is below the set temperature, for example, 55 ° C., it is determined that the hot water in the hot water storage tank 4 is not boiling. Then, the compressor 1 and the circulation pump 5 are turned on to start the heat collecting operation. On a sunny summer day, the solar radiation is high and the outside temperature is high, so that a very high output is obtained and the water boils quickly.

On the contrary, when the weather is bad and the solar radiation sensor 6 does not detect the set illuminance or when it is sunset, high output cannot be obtained, so that the heat collecting operation is automatically stopped regardless of the hot water temperature. It has become. At this time, when performing the heat collection operation, the operation mode is switched to “manual” by the remote controller 9 and the heat collection operation is performed.

[0008]

The conventional solar water heater using the above-described structure has the following problems.

(1) Since the heat collection operation is controlled by the sunshine, the operation of the compressor is started in the early morning in the summer, and the operation noise is high, causing trouble to the neighborhood.
Since the operation is started from a time period when the amount of solar radiation is small, the result is that the heat collecting operation is performed for a relatively long time. There was a problem that an efficient driving mode was required.

(2) In winter, when the amount of solar radiation is low and the temperature is low, the amount of heat collected during the day is insufficient, so that it is necessary to use the heat collecting operation using atmospheric heat at night. Accordingly, there is a problem that the usability is extremely poor.

(3) Daily temperature during the middle period, etc.
Since the solar radiation condition changes, the selection of the operation mode cannot be understood, so that an appropriate heat collecting operation cannot be performed and a desired hot water cannot be secured.

(4) Since the heat collecting operation is affected by external factors such as climate and weather, it is not possible to secure hot water in accordance with a living pattern, and as a result, it is used only in "manual" operation. This resulted in the use of wasteful use, which was not effective in terms of usability and economy.

[0013] The present invention solves the above-mentioned problems, and improves the living environment, ease of use, and economy by performing efficient heat collecting operation in accordance with a living pattern without being influenced by climate and weather. The purpose is to achieve it.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a heat collecting apparatus which circulates a refrigerant through a heat collecting circuit including a heat collector, a heat exchanger and a compressor to secure a predetermined amount of heat. A water circulation device that circulates water through a hot water supply circuit including a hot water storage tank, a circulation pump, and the heat exchanger and absorbs heat through the heat exchanger; a temperature detection unit that detects a temperature of the hot water storage tank; and the hot water storage tank A heat collector control unit that drives the heat collector so that the temperature of the heat collector falls within a target temperature range; a time measuring unit that measures a current time; and an operation time zone storage that stores a time zone in which the heat collector can be operated. Unit, and a heat collection operation start determination unit that compares the output of the clocking unit and the data of the operation time zone storage unit to determine the start of operation of the heat collection device, and performs operation from the heat collection operation start determination unit. When the signal is output, the control signal of the heat collector control unit So as to control the operation of the heat collector device based.

According to the above invention, regardless of the sunshine conditions,
Since the heat collection operation is performed during the operation time period stored in advance, the heat collection operation is performed every day according to the living pattern without being affected by external factors such as climate and weather. It is possible to operate the compressor, and the compressor starts operating early in the morning, generating a loud noise, and there is no need to worry about disturbing the neighborhood, which can greatly contribute to improving the living environment. In addition, during periods when the amount of solar radiation can be secured, such as during the summer, the desired hot water can be secured in a short heat-collecting operation by storing the operating time period by focusing on the time period during which the amount of solar radiation peaks during the day. It is possible to improve economic efficiency by extremely efficient operation.

Further, even in the winter season where the amount of solar radiation is small and the temperature is low, the operation time zones are stored separately during the daytime and nighttime, so that the heat quantity that is insufficient only by daytime heat collection operation is stored at nighttime. Since the heat collection operation is automatically started in the operation time zone, the shortage of heat can be compensated, and the trouble of switching the operation mode to “manual” every time can be omitted, and the usability can be improved.

[0017] When a late-night charge system is contracted, the economic efficiency can be improved by storing the nighttime operation time period in the late-night power time period in which the electricity rate is low.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A solar hot water supply apparatus according to a first aspect of the present invention is a collector that circulates a refrigerant through a heat collection circuit including a heat collector, a heat exchanger, and a compressor to secure a predetermined amount of heat. A heat device, a water circulation device that circulates water in a hot water supply circuit including a hot water storage tank, a circulation pump, and the heat exchanger and absorbs heat through the heat exchanger; a temperature detection unit that detects a temperature of the hot water storage tank; A heat collector control unit that drives the heat collector so that the temperature of the hot water storage tank is within a target temperature range; a timer that counts a current time; and an operation time that stores a time zone in which the heat collector can be operated. A heat storage operation start determination unit that compares the output of the time keeping unit with the data of the operation time period storage unit to determine the start of operation of the heat collection device; When an operation signal is output from the controller, the control of the heat collector controller is performed. So as to control the operation of the heat collector device based on the signal.

Since the heat collecting operation is performed during the operation time period stored in advance irrespective of the sunshine conditions, the heat collecting operation can be performed according to the living pattern without being influenced by external factors such as climate and weather. Heating operation can be performed during the set operating hours every day, and the compressor starts operating early in the morning, generating loud noises and eliminating concerns about disturbing the neighborhood, greatly contributing to the improvement of the living environment. it can. Also,
In summer and other times when the amount of solar radiation can be secured, the operating time zone is memorized intensively during the daytime when the amount of solar radiation peaks, so that the desired hot water can be secured in a short heat collection operation And economic efficiency can be improved by extremely efficient operation.

Further, even in the winter season when the amount of solar radiation is small and the temperature is low, the operation time zones are stored separately during the daytime and at nighttime, so that the amount of heat that is insufficient only by daytime heat collection operation is stored at nighttime. Since the heat collection operation is automatically started in the operation time zone, the shortage of heat can be compensated, and the trouble of switching the operation mode to “manual” every time can be omitted, and the usability can be improved.

When a late-night rate system is contracted, the economic efficiency can be improved by storing the nighttime operating hours in the late-night power hours when the electricity rate is low.

In the solar water heating apparatus according to the second aspect, the first operation mode in which the heat collection operation start determining section always operates regardless of the current time, and a comparison between the timer means and the operation time zone storage section. The operation signal of the heat collecting device is output according to the operation mode set by the operation switching unit that switches between the second operation mode in which operation is performed based on the result.

Since the first driving mode in which manual driving can be performed and the second driving mode in which driving is automatically performed in the stored driving time zone can be arbitrarily selected, a normal life pattern can be selected. Can automatically perform efficient operation by selecting the second operation mode, and can improve economy and usability.

In a case where hot water runs out due to the use of a large amount of hot water, the operation can be performed regardless of the time zone by selecting the first operation mode. It is possible to improve the usability by avoiding the phenomenon of running out of hot water.

According to a third aspect of the present invention, in the solar water heater, the operating time zone storage unit stores at least two types of operating time zones, a first operating time zone and a second operating time zone. The operation time zone can be arbitrarily selected by a specific operation of the operation switching means.

The second operation mode in which the operation is automatically performed in the stored operation time period includes two types of operation time periods, for example, daytime as the first operation time period and nighttime as the second operation time period. It is designed to allow for driving that takes into account life patterns and economy. That is, it is stored as the first operation time period in the daytime when a large amount of solar radiation can be secured and efficient operation is possible, and the second operation time period is used during the late night power time period when the electricity rate is cheap.
By storing as the driving time zone, economical automatic driving in accordance with the life pattern can be performed.

Further, in the solar hot water supply apparatus according to the fourth aspect, the operation switching means switches between the first operation mode and the second operation mode in a normal operation, and performs the first operation in a continuous operation for a predetermined time. The operation time zone and the second operation time zone can be switched.

Since the operation mode can be switched and the operation time period can be switched by changing the operation method with one operation switching unit, the configuration and the operation can be simplified.

Further, in the solar water heating apparatus according to the fifth aspect, the first operating time zone and the second operating time zone stored in the operating time zone storage section can be arbitrarily changed by the operating time zone changing means. Is possible.

By changing the driving time zone in accordance with the life pattern and sunshine conditions that change according to the season and the like, more efficient driving can be achieved, and usability and economy can be improved.

Further, in the solar hot water supply apparatus according to the sixth aspect, one of the first operating time zone and the second operating time zone stored in the operating time zone storage unit is:
The operation time period includes at least the midnight power time period.

Since one of the operation time periods is set in the midnight power time period when the electricity rate is low, the heat collection operation using atmospheric heat can be performed at a low electricity rate, and a desired hot water can be secured at night. can do. Thereby, it is possible to reliably cope with the first hot water supply in the morning, to improve the usability, and to improve the economic efficiency.

Further, in the solar hot water supply apparatus according to a seventh aspect, the heat collector control section has a temperature determining section for determining whether or not the temperature of the hot water storage tank has reached a target temperature range.
In the operation mode, and when the operation time zone not including the midnight power time zone is selected, when the temperature determination unit detects that the temperature reaches the target temperature range, the heat collecting device in the operation time zone Not to re-drive.

Then, in order to minimize the heat collecting operation during the daytime when the electricity rate is high, once the boiling is detected, the heat collecting operation is frequently performed by a slight change in the temperature of the hot water storage tank. Therefore, it is possible to provide an operation mode that considers economy.

[0035]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram of a solar hot water supply apparatus according to an embodiment of the present invention. Note that components having the same reference numerals as those of the conventional example have the same structure, and description thereof will be omitted.

In FIG. 1, the system of the solar hot water supply system includes a heat collector 17 for circulating a refrigerant through a heat collector circuit including a heat collector 3, a heat exchanger 2, and a compressor 1 to secure a predetermined amount of heat. A water circulation device 18 that circulates water through a hot water supply circuit including a hot water storage tank 4, a circulation pump 5, and the heat exchanger 2 and absorbs heat through the heat exchanger; and a temperature detection unit 7 that detects the temperature of the hot water storage tank. It is composed of

FIG. 2 is a block diagram showing the control device 8 of the solar water heater according to the embodiment of the present invention.

The heat collecting device control section 20 is selected by a time measuring means 23 for measuring the current time, an operation time period storing section 24 for storing a time period during which the heat collecting device can be operated, and an operation switching means 27. The instruction from the heat collection operation start determining unit 22 that determines the start of operation by comparing the data by the operation switching determining unit 26 that determines the operating mode that has been set, and the hot water storage tank 4 that is detected by the temperature detecting unit 7 including a thermistor or the like Of the heat collecting device 17 according to the temperature of the
And the water circulation device 18 is driven.

The operable time zone stored in the operating time zone storage section 24 can be changed by the operating time zone changing means 25.

Further, the heat collector control section 20 determines that the hot water temperature has reached the target temperature based on the temperature detected by the temperature detecting section 7, and instructs the heat collector to be driven again during the operation time period. And a temperature attainment determination unit 21 for controlling so as not to perform.

The operation of the above configuration will be described with reference to the flowcharts of FIGS.

First, at step 30, the operation switching means 27
It is determined whether or not the operation switching key has been continuously pressed for one second for t1 seconds.
The process proceeds to step 31 if the button has been continuously pressed.
In step 31, the operation switching determination unit 26 determines the switching state of the operation mode. If the three modes can be switched, the process proceeds to step 32. If the two modes can be switched, the process proceeds to step 34. move on. Step 32
Then, the operation mode switching state is set to a state in which the two types of modes can be switched, the operation mode is set to the daytime mode, and the process proceeds to step 43. Then, in step 34, the operation mode switching state is set to a state in which three types of modes can be switched, the operation mode is set to two night modes, and the process proceeds to step 43. In step 36, it is determined whether or not the operation switching key has been operated by the operation switching means 27. If the operation switching has not been performed, the process proceeds to step 43, and if the operation switching has been performed, the process proceeds to step 37. Step 3
At 7, it is determined whether the operation mode is the continuous mode. If the operation mode is not the continuous mode, the process proceeds to step 38. If the operation mode is the continuous mode, the process proceeds to step 42. The operation mode is set to daytime operation, and the process proceeds to step 43. . At step 38, it is determined whether or not the operation mode is the daytime mode. If the operation mode is not the daytime mode, the process proceeds to step 39. If the operation mode is the daytime mode, the process proceeds to step 41, and the operation mode is set to the continuous operation. move on. In step 39, the switching state of the operation mode is determined by the operation switching determination unit 26. If the three modes can be switched, the process proceeds to step 40, the operation mode is set to night operation, and the process proceeds to step 43. If not, proceed to step 41.

Further, in step 43, it is determined whether or not the operation for changing the driving time period is performed by the driving time period changing means 25. If the operation for changing the driving time period is not performed, the process proceeds to step 48. If the operation has been performed, the process proceeds to step 44. In step 44, it is determined whether the operation for changing the driving time zone is an operation for changing the time zone for daytime driving. If the operation is not for changing the time zone for daytime driving, the process proceeds to step 46, where the time for daytime driving is changed. If it is a band operation, in step 45, the daytime operation start time and daytime operation end time stored in the operation time period storage unit 24 are changed to the values set by the operation time period change means 25.
Proceed to 8. In step 46, it is determined whether or not the operation for changing the driving time zone is an operation for changing the time zone of night driving. If the operation is not the time zone changing operation for night driving, the process proceeds to step 48, and the operation for night driving is performed. If the operation is a time zone operation, in step 47, the night operation start time and the night operation end time stored in the operation time zone storage unit 24 are changed to the values set by the operation time zone change unit 25. 4
Proceed to 8.

Further, at step 48, it is determined whether or not the operation mode is the daytime operation. If the operation mode is not daytime operation, the process proceeds to step 49. If the operation mode is daytime operation, the process proceeds to step 52. The stored daytime driving time setting is adopted as the driving time zone, and
Proceed to. In step 49, it is determined whether the operation mode is night operation or not.
If the operation is a night operation, the operation proceeds to step 47, the time setting for night operation stored in the operation time period storage unit 24 is adopted as the operation time period, and the operation proceeds to step 53.

Further, in step 53, the current time measured by the timer 23 is compared with the operation time zone adopted in the operation mode by the heat collection operation start judging section 22, and the current time is set in the range of the operation time zone. It is determined whether or not it is within the range. If it is within the range, the process proceeds to step 54, and if it is outside the range, the process proceeds to step 59, and the heat collecting device control unit 20 issues a stop instruction to the heat collecting device 17 and the water circulation device 18, After a series of processes, the process returns to step 30. In step 54, it is determined whether or not the hot water temperature of the hot water tank detected by the temperature detecting section 7 is equal to or higher than the target temperature X1 ° C.
Go to 5. In step 55, it is determined whether or not the hot water temperature of the hot water tank detected by the temperature detector 7 is lower than a temperature obtained by subtracting a predetermined differential X2 ° C from the target temperature X1 ° C. Proceeding to step 56, if it is lower than (X1-X2) ° C., a series of processing is completed and the process returns to step 30. In step 56, it is determined whether or not the operation mode is daytime operation. If the operation mode is daytime operation, the process proceeds to step 57;
Proceed to. In step 57, the temperature attainment determination section 21 determines whether or not there is experience of performing the heat collecting operation during the operation time period to reach the target temperature. If there is experience of reaching the target temperature, the process proceeds to step 59, If there is no experience, the process proceeds to step 58, in which the heat collecting device controller 20 issues a drive instruction to the heat collecting device 17 and the water circulating device 18, ends a series of processing, returns to step 30, and repeats this series of operations. repeat.

[0047]

As described above, according to the solar hot water supply apparatus of the first aspect, since the heat collecting operation is performed during the operation time period stored in advance regardless of the sunshine conditions, the climate , Without being affected by external factors such as weather,
Heat collection operation can be performed every day according to the daily life according to the life pattern, and the compressor starts operation early in the morning, generating loud noises, and there is no need to worry about disturbing the neighborhood. Can greatly contribute to improvement. In addition, during periods when the amount of solar radiation can be secured, such as during the summer, the desired hot water can be secured in a short heat-collecting operation by storing the operating time period by focusing on the time period during which the amount of solar radiation peaks during the day. It is possible to improve economic efficiency by extremely efficient operation.

Further, even in the winter season where the amount of solar radiation is small and the temperature is low, the operation time zones are stored separately during the daytime and at nighttime, so that the amount of heat which is insufficient only by daytime heat collection operation is stored at nighttime. Since the heat collection operation is automatically started in the operation time zone, the shortage of heat can be compensated, and the trouble of switching the operation mode to “manual” every time can be omitted, and the usability can be improved.

When a late-night rate system is contracted, the economical efficiency can be improved by storing the nighttime operating hours in the late-night power hours when the electricity rate is low.

Further, according to the solar hot water supply apparatus of the second aspect, the first operation mode in which manual operation is possible,
Since the second driving mode in which driving is automatically performed in the memorized driving time zone can be arbitrarily selected, in a normal life pattern, by selecting the second driving mode, efficient operation is automatically performed. Driving can be performed, and economy and usability can be improved.

In a case where hot water is used up and the hot water runs out, the operation can be performed regardless of the time zone by selecting the first operation mode. It is possible to improve the usability by avoiding the phenomenon of running out of hot water.

According to the third aspect of the invention, the second operation mode in which the operation is automatically performed in the stored operation time period includes two operation time periods, for example, the first operation time period. The daytime is set as a time zone, and the nighttime is set as a second driving time zone, so that driving can be performed in consideration of life patterns and economy. In other words, by storing a large amount of solar radiation and storing it as the first operation time in the daytime when efficient driving is possible, and storing it as the second operation time in the midnight power time when the electricity rate is cheaper, It is possible to perform economical automatic driving according to the life pattern.

According to the solar hot water supply apparatus of the fourth aspect, the operation mode can be switched and the operation time zone can be switched by changing the operation method by one operation switching means. Simplification and simplification of operation can be achieved.

According to the solar hot water heater according to the fifth aspect, more efficient operation is possible by changing the operation time zone according to the life pattern and the sunshine condition which change according to the season and the like. Thus, usability and economic efficiency can be improved.

According to the solar hot water supply apparatus of the sixth aspect, since one of the operation time zones is set in the late night power time zone in which the electricity rate is low, the heat collection by the atmospheric heat at the low electricity rate. Operation can be performed, and desired hot water can be secured at night. Thereby, it is possible to reliably cope with the first hot water supply in the morning, to improve the usability, and to improve the economic efficiency.

Further, according to the solar hot water supply apparatus according to the present invention, in order to minimize the heat collecting operation during the daytime when the electricity rate is high, a small amount of water is detected once the boiling is detected. Since the frequent heat collecting operation is restricted by the temperature change of the hot water storage tank, it is possible to provide an operation mode in which economy is considered.

[Brief description of the drawings]

FIG. 1 is a system diagram of a solar water heater according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control device of the solar water heater.

FIG. 3 is a flowchart showing the operation of the solar water heater.

FIG. 4 is a flowchart showing the operation of the solar water heater.

FIG. 5 is a system diagram of a conventional solar water heater.

FIG. 6 is a block diagram showing a control device of a conventional solar water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Heat exchanger 3 Heat collector 4 Hot water storage tank 5 Circulation pump 7 Hot water temperature sensor 17 Heat collector 18 Water circulation device 20 Heat collector control part 21 Temperature reaching judgment part 22 Heat collection operation start judgment part 23 Clocking means 24 Operating time zone storage unit 25 Operating time zone changing unit 26 Operation switching determination unit 27 Operation switching unit]

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masafumi Hashimoto 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (7)

[Claims] 1. A heat collecting device for circulating a refrigerant in a heat collecting circuit comprising a heat collector, a heat exchanger and a compressor to secure a predetermined amount of heat, a hot water storage tank, a circulation pump, and a hot water supply comprising the heat exchanger. A water circulating device that circulates water through a circuit and absorbs heat through the heat exchanger, a temperature detector that detects the temperature of the hot water tank, and the heat collector so that the temperature of the hot water tank falls within a target temperature range. A heat collecting device control unit to be driven; a time measuring unit for measuring a current time; an operating time period storing unit for storing a time period during which the heat collecting device can be operated; an output of the time measuring unit and the operating time period storing unit A heat collection operation start determination unit that determines the start of operation of the heat collection device by comparing the data of the above, when the operation signal is output from the heat collection operation start determination unit, the control of the heat collection device control unit A sun adapted to control the operation of the heat collector based on a signal Use water heater. And a second operation mode for performing operation based on a result of comparison between a timer and an operation time zone storage unit. The hot water supply device using solar heat according to claim 1, wherein an operation signal of the heat collecting device is output in accordance with an operation mode set by operation switching means for switching between the two. 3. The operating time zone storage unit stores at least two types of operating time zones, a first operating time zone and a second operating time zone, and specifies any one of the operating time zones by a specific operation of the operation switching means. 3. The hot water supply system using solar heat according to claim 2, wherein the hot water supply system can be selected from the following. 4. The operation switching means switches between the first operation mode and the second operation mode in a normal operation, and switches between the first operation time period and the second operation time period in a continuous operation for a predetermined time. The hot water supply device using solar heat according to claim 2 or 3, wherein the hot water supply device can be used. 5. The solar thermal system according to claim 3, wherein the first operation time zone and the second operation time zone stored in the operation time zone storage section can be arbitrarily changed by an operation time zone changing means. Use hot water supply equipment. 6. A method according to claim 1, wherein at least one of the first operating time zone and the second operating time zone stored in the operating time zone storage unit is an operating time zone including at least a midnight power time zone. Item 3. A solar water heater utilizing the solar heat according to item 3 or 4. 7. The heat collector control section has a temperature determining section for determining whether or not the temperature of the hot water tank has reached a target temperature range,
In the second operation mode, when an operation time period not including the midnight power time period is selected, if the temperature determination unit detects that the temperature reaches the target temperature range, the temperature is collected in the operation time period. 7. The solar water heater according to claim 2, wherein the heat device is not driven again.