JP2002005531A - Solar powered water heater and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar powered water heater excellent in antifreezing performance, and further provide its control method. SOLUTION: A solar powered water heater 1 includes a collector 2 for collecting solar heat, a hot water storage tank 3 for storing water located at a lower position than the collector 2, air vent means 21 for exhausting air in the collector 2, a collector water level detector 22 for deciding that water is existent in the collector 2, a piping 4 for communicating the collector 2 and the hot water storage tank 3, a three way valve 5 for changing over the connection of the piping 4, a pump 6 for lifting water to the collector 2 from a lower connection port 32 of the hot water storage tank 3 through the three way valve 5 and the piping 4, and a collector temperature detector 23 for detecting the water of the water in the collector 2. In the apparatus 1, a fresh air temperature detector 7 is disposed in the vicinity of the solar powered water heater 1 for detecting the temperature of fresh air, and further a control section 9 is provided for deciding that the water contained in the hot water storage tank 3 is sent to the collector 2 through the pump 6 with the aid of the collector temperature detector 23 and the fresh air temperature detector 7.

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 for supplying water to a bath or a kitchen by solar heat and a control method thereof.

[0002]

2. Description of the Related Art The applicant of the present invention has already proposed a solar water heater and a control method thereof in Japanese Patent Application No. 11-073396 as prior art of the present application. In the preceding solar water heater, the low temperature sensor of the hot water tank and the high temperature sensor of the collector are used as a condition for pumping water to the collector.

[0003]

However, the conventional solar water heater has the following problems. a. In Japan, most of the Japanese archipelago, except for some areas such as Okinawa, may have a temperature below freezing due to the cold air from the continent, which is usually called a cold wave, overhanging the Japanese archipelago in winter. Even if the temperature falls below freezing, the temperature of the low-temperature sensor in the hot water tank is determined by the temperature of the water in the hot water tank, and the temperature of the high-temperature sensor in the collector can be a predetermined value even if the outside air temperature is below freezing and there is solar radiation. Since the temperature rises to the temperature, a temperature difference occurs between the low-temperature sensor and the high-temperature sensor, and even if the outside air temperature is below zero, water is pumped during the daytime. However, since the outside air temperature is below the freezing point, the temperature of the pipes in the shade does not rise and freezing occurs when pumping is performed, or the water in the pipes freezes while the pipes are held for a predetermined time. In other words, if this pipe freezes, the water after collecting heat from the collector to the hot water storage tank is performed due to the head of the collector and the hot water storage tank.
In the worst case, there is a problem that the solar water heater is damaged by freezing.

B. A method of determining the outside air temperature using a high-temperature sensor and a low-temperature sensor to prevent freezing is also conceivable, but the high-temperature sensor is not in contact with the outside air, and when there is no solar radiation at night, it is not possible to detect the outside air temperature indirectly. It is possible,
During the daytime, even if the outside air temperature is below the freezing point, the temperature rises at a stretch due to the heat collection of the collector, and there is a problem that a certain relationship with the outside air temperature cannot be estimated. Also,
Since the low-temperature sensor detects the temperature of the water contained in the hot water storage tank, it naturally has no relation to the outside air temperature, so that there is a problem that freezing cannot be prevented only by the high-temperature sensor and the low-temperature sensor.

C. To further supplement: a. As a countermeasure against the above, if an outside air temperature sensor that detects the outside air temperature is provided separately, if the outside air temperature is detected and the temperature becomes close to below freezing, pumping will not be performed even if the pumping conditions based on the temperature detected by the low temperature sensor and the high temperature sensor Although there is a method of providing such a sensor, providing another outside air temperature sensor in addition to the low-temperature sensor and the high-temperature sensor has a problem that the sensor itself and parts and means for installing and operating the sensor are required, thereby increasing costs. .

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a solar water heater capable of preventing freezing of equipment and maintaining heat collecting performance without increasing the number of temperature detectors.

[0007]

SUMMARY OF THE INVENTION A solar water heater according to the present invention has a collector for collecting solar heat and raising the temperature of water inside the collector, water which is lower than the collector and is sent to the collector, and the temperature of which is raised by the collector. A hot water storage tank for storing water, an air vent means located above the collector for discharging air in the collector, and a collector water level detector located above the collector to determine that there is water in the collector; A pipe connecting the collector and the hot water tank, a three-way valve for switching the connection of the pipe to a connection port provided at an upper portion and a lower portion of the hot water tank, and a three-way valve and a pipe through a lower connection port of the hot water tank. A solar water heater having a pump for pumping water to the collector and a collector temperature detector for detecting a temperature of water contained in the collector, wherein an outside air for detecting a temperature of outside air is provided near the solar water heater. There is a temperature detector, and there is a control unit that determines whether the water contained in the hot water tank is sent to the collector by the pump by the collector temperature detector and the outside air temperature detector, or collects solar heat and internally A collector for raising the temperature of the water, a hot water storage tank located at a lower position than the collector for sending water to the collector, and storing water heated by the collector, and discharging air in the collector above the collector. A collector water level detector that is located above the collector and determines that there is water in the collector; a pipe connecting the collector and the hot water tank; and an upper and a lower part of the hot water tank. A three-way valve for switching the connection of the pipe to the connection port, a pump for pumping water from the lower connection port of the hot water tank to the collector via the three-way valve and the pipe, and detecting a temperature of water contained in the collector. Collector temperature In the solar water heater having a detector, there is an outside air temperature detector for detecting the temperature of the outside air in the vicinity of the solar water heater, and determines whether water contained in the hot water tank is sent to the collector by the pump. A control method performed by a collector temperature detector and the outside air temperature detector, and in addition to these contents, the control unit performs pumping determination means for performing water pumping by the collector temperature detector and the outside air temperature detector, Heat collection determining means for determining that the temperature detected by the collector temperature detector rises for a first predetermined time after starting heat collection after pumping, and continuing the heat collection at the collector; Means for judging a decrease in the temperature detected by the collector temperature detector or when the first predetermined time has elapsed from the start of heat collection, switching the three-way valve to drop water into the hot water storage tank; Start pumping Maximum operation determining means for repeatedly performing pumping, collecting heat, and dropping water for a second predetermined time, and continuing the collector during the first predetermined time during heat collection after the second predetermined time has elapsed. If the temperature detected by the temperature detector drops, the water is dropped and the pumping determination means determines that pumping is possible.Even if the pumping stop means stops pumping to the collector for a third predetermined time, Alternatively, in the control method, water is pumped by the collector temperature detector and the outside air temperature detector, and the temperature detected by the collector temperature detector rises for a first predetermined time after heat collection is started after the pumping. To continue the heat collection at the collector, and if the detected temperature of the collector temperature detector falls during the first predetermined time or the first predetermined time has elapsed, the three-way valve is turned off. Switch over and drop into the hot water tank, first pumping Pumping, collecting heat, and dropping water are repeated for a second predetermined time from the beginning, and after the second predetermined time has elapsed, the collector temperature detection is performed during the first predetermined time during heat collection. If the detected temperature of the vessel falls, water is dropped, and then, even if it is determined that pumping is possible, pumping to the collector is stopped for a third predetermined time,
Further, immediately after the pumping of water from the hot water tank to the collector is started by the pump, the flow path of the three-way valve is connected to the lower connection port of the hot water tank and the collector so as to be in an open position, and the pumping is started. After a lapse of a fourth predetermined time, the pump has a three-way valve control means for moving the opening area of the flow path of the three-way valve in a direction in which the opening area is reduced, or starts pumping of water from the hot water tank to the collector by the pump Immediately after,
The flow path of the three-way valve is connected to the hot water tank lower connection port and the collector so as to be in an open position, and after a lapse of a fourth predetermined time from the start of pumping, the opening area of the flow path of the three-way valve decreases. This is made possible by a control method that moves the object.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the solar water heater according to the present invention will be described below with reference to the drawings. Figure 1
FIG. 2 is a schematic diagram of a solar water heater, FIG. 2 is a schematic diagram of each control means incorporated in the control unit, FIG. 3 is a schematic diagram of a connection system of a three-way valve, and FIG. 5 is a flowchart at the time of heat collection, FIG. 6 is a flowchart at the time of falling water, and FIG. 7 is a flowchart at the time of pumping prohibition. In the description of each part, the same portions in each drawing are denoted by the same reference numerals, and description thereof is omitted.

In the configuration of the solar water heater of the present invention shown in FIG. 1, reference numeral 1 denotes a solar water heater, and reference numeral 2 denotes a position higher than a hot water storage tank described later, for example, provided on a building roof or a roof, and built therein by collecting sunlight. A collector for raising the temperature of the water to be heated, 21 is a large-diameter air bleeding means on the upper part of the collector 2 so that air can escape easily, 22 is a collector water level detector for detecting the presence of water in the collector 2, 23 Is the collector 2
A collector temperature detector 3 for detecting the temperature of water or air contained therein, which is attached to the upper part of the tank, stores water for sending the water contained in the collector 2 (hereinafter referred to as "pumping") and rises in the collector 2. A hot water tank for storing hot water that has been dropped (hereinafter, referred to as water falling) again, 31 is an upper connection port provided at the upper part of the hot water tank 3, and 32 is a lower part provided at a lower part of the hot water tank 3. The connection port 4 is a common pipe through which water from the collector 2 and the hot water storage tank 3 is pumped and dropped. The reference numeral 41 is a connection pipe connecting the upper connection port 31 and the common pipe 4. The lower connection port 32 and the common pipe 4 are connected to each other, and the pumping pipe 44 is used only when pumping water. A water supply pipe 44 supplies water to the hot water storage tank 3 from outside. A water supply valve 46 for supplying and stopping the supply of water is A hot water tank water level detector for detecting the water level of the water contained in the hot water tank 3 using an electrode, a float, or the like provided in the tank 3, and a three-way switch 5 for switching the common pipe 4 between the falling water pipe 41 and the pumping pipe 42. Valve 6 is the lower connection port 3
A pump provided in the pumping pipe 42 near 2, 7 is an outside air temperature detector for detecting the outside air temperature near the solar water heater 1, 8 is a hot water supply pipe, and 81 is water from the hot water supply pipe 8. And a check valve for preventing backflow into the hot water storage tank 3,
An accumulator 82 is also called a pulsation preventer for preventing a rapid change in the water pressure in the hot water supply pipe 8, and a 83 detects the water pressure in the hot water supply pipe 8 by opening or closing a contact by a voltage change or a predetermined water pressure. A pressure detector 84 is a water flow detector that converts the flow of water in the hot water supply pipe 8 into a pulse per time or detects when a contact is opened or closed by a predetermined amount of water, and 85 is provided in a bathroom or a kitchen. A hot water supply port at a terminal of the hot water supply pipe 8 operated by a user when using hot water, and a hot water supply port 9 according to detection results of the collector water level detector 22, the collector temperature detector 23, and the outside air temperature detector 7, The control unit controls the three-way valve 5 and the pump 6.

In FIG. 2, the control unit 9 includes a pumping determining means 91, a heat collecting determining means 92, a water drop determining means 93, a maximum operation determining means 94, a pumping inhibiting means 95,
6 three-way valve control means and the like.

FIG. 3A is a view for explaining a pipe connection state in which the three-way valve 5 is at a pumping position. The pumping pipe 42 and the common pipe 4 are in communication via the three-way valve 5.

FIG. 3B is a view for explaining a pipe connection state in which the three-way valve 5 is at the closed position. The common pipe 4, the water-falling pipe 41, and the pumping pipe 42 are connected to the three-way valve 5.
Therefore, it is not in communication with any pipe.

FIG. 3C is a view for explaining a pipe connection state in which the three-way valve 5 is located at a water drop position. The common pipe 4 and the water drop pipe 41 communicate with each other through the three-way valve 5.

FIG. 3D is a view for explaining a pipe connection state in which the three-way valve 5 is stopped while moving from the pumping position to the closed position, and the pumping pipe 42 and the common pipe 4 are connected via the three-way valve 5. They communicate with each other with a reduced opening area.

The control method of the solar water heater according to the present invention described with reference to FIGS. 1, 2 and 3 will be described with reference to FIGS. 4, 5, 6 and 7.
This will be described with reference to the flowchart of FIG.

FIG. 4 is a flow chart of a pumping mode (showing a series of operations during pumping of the solar water heater 1) in which water contained in the hot water tank 3 of the solar water heater 1 of the present invention is sent to the collector 2. First, as an initial state, preconditions before entering the pumping mode will be described. In the solar water heater 1 configured as shown in FIG. 1, the water is stored in the hot water tank 3 by opening a water supply valve 45 provided in the middle of the water supply pipe 44 until the water is detected by the hot water tank water level detector 46. It is assumed that the collector 2 does not contain water. The control unit 9 is supplied with power from the outside and is in a controllable state, and the three-way valve 5 is in a water-fall position (FIG. 3C).
It is assumed that In this state, the pumping mode starts and the pumping mode starts (step 1). First, the pumping determination unit 91 detects the outside air temperature with the outside air temperature detector 7 (step 11), and the pumping determination unit 91 determines whether the detected temperature of the outside air temperature detector 7 exceeds tf (step 11). Step 12). If the temperature is equal to or less than tf at this time, if the outside air temperature is low and the pump enters the pumping mode, there is a possibility that the common pipe 4 may be frozen. Therefore, the process returns to step 11 so as not to enter the pumping mode. Therefore, the temperature of tf is determined as a temperature slightly higher than the freezing temperature of water, and is set to 3 ° C. in the present embodiment. Next, in step 12, when the time exceeds tf, the collector temperature detector 23
To detect the temperature inside the collector (step 13), and the pumping determination means 91 confirms that the temperature difference between the collector temperature detector 23 and the outside air temperature detector 7 is equal to or more than Δtm (step 14). The temperature difference Δtm may be such that the temperature difference between the collector temperature detector 23 and the outside air temperature detector 7 is constant (for example, constant at 8 ° C.) or may be corrected by the outside air temperature or the collector temperature. As a correction method, a method of increasing the temperature difference Δtm as the outside air temperature increases,
When the outside air temperature exceeds 25 ° C., the collector temperature may be 40 ° C. or higher. In addition, pumping determination means 91
If the temperature difference is smaller than Δtm, it is determined that heat collection cannot be performed sufficiently, and the process waits until the temperature difference becomes equal to or larger than Δtm, and returns to step 11; . When the pumping determination means 91 determines that pumping is possible, the three-way valve 5 is driven to the pumping position (FIG. 3A) (step 15), and then the pump 6 is driven (step 16). The built-in water is pumped to the collector 2. Although FIG. 4 shows that the process proceeds to step 21 after step 16, the description of step 21 and step 22 will be made later. The pumping determination means 91 continues pumping until the collector water level detector 22 detects that water has entered the upper part of the collector 2 (step 1).
7) Upon detection, the three-way valve 5 is driven to the closed position (FIG. 3B) (step 18), the drive of the pump 6 is stopped (step 19), and the pumping mode ends (step 2).

Referring to FIG. 4, the flow of steps 21 and 22 after step 16 will be described. Step 1
After 6, the three-way valve control means 96 confirms that T4 time has elapsed (step 21), and drives the three-way valve 5 by a predetermined angle in the direction of the closing position (FIG. 3D). The passage cross-sectional area is reduced (step 22), and in this state, the process waits until the collector water level detector 22 detects that water has entered the upper part of the collector 2 (step 17). This is because even if the collector water level detector 22 detects that water has entered at the end of pumping and closes the three-way valve 5 and stops driving the pump 6, a slight delay occurs.
This is to prevent water from overflowing. Therefore,
The time T4 is determined by the amount of water per unit time (the amount of pumped water) of the pump 6 and the total amount of water that can be incorporated in the collector 2, the pumping pipe 42, and the common pipe 4. When the amount of water becomes slightly smaller than the total amount of water, The valve 5 may be driven at a predetermined angle in the closing direction. Although the three-way valve 5 has been described as having a predetermined angle, the three-way valve control means 96 may detect the angle by providing the three-way valve 5 with a contact such as a potentiometer or a switch corresponding to the angle. The three-way valve 5 is moved from the pumping position (FIG. 3A) to the closing position (FIG.
(B)), the time is measured, and a drive time T6 at which a predetermined angle is obtained from the time is calculated.
(D)).

The operation of step 21 and step 22 in FIG. 4 described above will be supplementarily described again. What is required for pumping of the pump 6 to the collector 2 is to shorten the pumping time and simultaneously with the pumping pipe 42, the common pipe 4 and the collector. 2
It is to replace the air inside with water (to completely deflate). Therefore, the above-described operation of the three-way valve 5 is for preventing the overflow of the water from the air release means 21.
Although it is effective to reduce the pumping amount of the pump 6, the pumping time is shortened and the performance of completely removing air is impaired. Further, when the pumping amount of the pump 6 can be switched, the price of the pump 6 rises and becomes uneconomical. Furthermore, if it is only to prevent overflow of water, the air bleeding means 21 itself can be prevented by using an automatic air bleeding valve (one that has a float or the like inside and closes the valve when the water level rises). If the valve diameter of the air vent valve is increased, the closing performance of the valve deteriorates, and the valve becomes expensive. Therefore, the valve is small (about 1 to 2 mm in diameter), and the air is not easily released even if the pump 6 has a large pumping amount. Pumping takes time. In addition, it becomes a cause of generating air pockets inside the collector 2 and the like, which causes a problem that the heat collection time is shortened or the heat collection efficiency is reduced. Further, when the air vent valve is an electromagnetic on-off valve or a motor valve, by mounting it on the upper part of the collector 2, control wiring and control means are required, which is not economical. Therefore, in the present embodiment, the air vent 21
Has no opening / closing means by itself and has the same diameter as the common pipe 4 or the like.

FIG. 5 shows a heat collecting mode (indicating a series of movements during the heat collection of the solar water heater 1) subsequent to the above-described water pumping mode. The heat collecting mode starts (step 3) after the pumping mode ends (step 2). ), The heat collection determining means 92 starts measuring the maximum heat collection time T1 (step 31). Next, the heat collection determining means 92 uses the collector temperature detector 23 to collect the collector 2.
The temperature of the water pumped inside is detected (step 32).
This is stored as the initial temperature tc1 (step 3
3). Next, the outside air temperature is detected by the heat collection determining means 92 (step 34), and it is confirmed that the outside air temperature exceeds the freezing prevention temperature tf (step 35). Here, if the temperature is equal to or lower than the freezing prevention temperature tf, the water collecting mode is ended at that time by the water drop judging means 93, and the routine proceeds to step 41. At the same time, after it is confirmed that the temperature exceeds the freezing prevention temperature tf, the heat collection determining means 92 waits for the heat collection waiting time T5 (step 36). The detected temperature is calculated as a second temperature tc2.
(Step 37), and the second temperature tc2
Is compared with the initial temperature tc1, and the second temperature tc2 is higher than or equal to the initial temperature tc1 (tc2 ≧ tc1).
(Step 38), the initial temperature tc1 is erased, the second temperature tc2 is replaced with the initial temperature tc1 (step 39), and further, it is confirmed that the maximum heat collection time T1 has not elapsed. If the maximum heat collection time T1 has not elapsed (step 40), the process returns to step 33 and repeats this operation. Steps 34 and 35, which are the anti-freezing operations, are also repeated at the same time as steps 33 to 40 are repeated. The temperature compared by the heat collection determining means 92 in step 38 in the middle of the repetition of steps 33 to 40 is the temperature measured before and the temperature measured after waiting for the heat collection waiting time T5, and after measuring the initial temperature tc1, 3 The second time is after the double heat collection waiting time T5 (2 × T5). If the temperature measured here is the third temperature tc3, the next comparison is whether the third temperature tc3 is greater than the second temperature tc2. Or, it is confirmed that they are equal (tc3 ≧ tc2). If it is determined in step 38 that the current measured temperature is lower than the previous measured temperature (tcx + 1 <tc
x) The collector 2 determines that heat is radiated due to insufficient solar radiation, and the waterfall determination means 93 proceeds to step 41 to end the heat collection mode. If the maximum heat collection time T1 has elapsed in step 40, the waterfall determination means 93 terminates the time measurement of the maximum heat collection time T1, and returns the counter storing the time measurement result to zero. At the same time, the temperature detected and stored by the collector temperature detector 23 is erased (step 41), and the heat collection mode ends (step 4).

Here, the maximum heat collection time T1 is determined by an experiment because it is determined by the internal capacity of the collector 2 and the heat collection efficiency of the collector 2, but in this embodiment, it is set to 30 minutes. The collector heat collecting temperature can be compared a plurality of times with the maximum heat collecting waiting time T1 for the heat collecting waiting time T5, and there is no point in comparing the detected temperature by the collector temperature detector 23 in a too short time. Therefore, in this embodiment, it is set to 8 minutes. Therefore, in the heat collecting mode of this embodiment, the maximum is 4
Each time, a comparison is made based on the temperature detected by the collector temperature detector 23.

FIG. 6 shows a waterfall mode (collector 2 of the solar water heater 1) subsequent to the heat collection mode described in FIG.
, Which indicates a series of movements when water falls into the hot water storage tank 3), the water collecting mode ends (step 4) by the water falling determining means 93, and then the water falling mode starts (step 5).
The control unit 9 drives the three-way valve 5 to the water drop position (FIG. 3C) (step 42), waits for a water drop waiting time T6 (step 43), and ends the water drop mode (step 6).

Since the collector 2 is located at a higher position than the hot water storage tank 3, the water contained in the collector 2 is dropped into the hot water storage tank 3 while sucking air from the air releasing means 21 only by switching the three-way valve 5 to the water drop position. . Therefore, the falling water waiting time T6 may be a time determined by the total amount of water in the collector 2 and the common pipe 4 and the drop between the collector 2 and the hot water storage tank 3, and may be a value obtained by adding some safety time to the time obtained by the experiment.

After the end of the falling water mode of FIG. 6 (step 6),
The control unit 9 immediately starts the pumping mode of FIG. 4 (step 1).
It is confirmed whether or not the pump is in the pumping prohibition mode (step 59). This detailed movement will be described later with reference to FIG. 7. If the pumping prohibited mode has been entered, the pumping prohibition mode starts (step 7). If the pumping prohibited mode has not been entered, the pumping mode starts again (step 1). .

FIG. 7 shows a pumping prohibition mode (a series of operations for prohibiting pumping of the solar water heater 1) performed in parallel with the pumping mode of FIG. 4, the heat collecting mode of FIG. 5, and the water dropping mode of FIG. After the first pumping mode is started (step 1) in the determination process for entering the pumping operation and the pumping prohibition mode, the maximum operation determining means 94 sets the maximum operation time T from the first pumping start.
2 was started (step 51), and there was a case where the process did not reach the maximum heat collection time T1 in the heat collection mode of FIG. 5 and proceeded to step 41 (the case of NO in steps 35 and 38)? Is confirmed (step 52). If there is none, the process waits until the pumping mode of FIG. 4, the heat collecting mode of FIG. 5, and the water falling mode of FIG. 6 are repeated. Usually, except for a part of the earth, the sun always sinks, the amount of solar radiation decreases, and heat is radiated at the collector 2. Therefore, the case of NO at step 38 in FIG. 5 occurs, and the process proceeds to the next step. The maximum operation time determination means 94 waits until the maximum operation time T2 is exceeded from the start of the first pumping (step 53). When the maximum operation time T2 is exceeded, the timer of the maximum operation time is reset to zero (step 54), and the pumping inhibition mode is started. Move on to (Step 7).

In step 53, pumping prohibition means 95
When it is determined that the pumping inhibition mode is to be entered, the pumping inhibition mode is notified to step 59 in FIG. 6, and the pumping mode in FIG. 4, the heat collection mode in FIG. 5, and the falling water mode in FIG. Move to mode start (step 7). When the pumping prohibition mode starts (step 7), the pumping prohibition means 95 waits for the elapse of the pumping prohibition time T3 (step 61). When the pumping prohibition time T3 elapses, the pumping prohibition mode is canceled and the pumping prohibition mode ends (step 8). , And the process proceeds to the pumping mode start (step 1) again. Starting the pumping mode (step 1) from this time is the first pumping mode again.

The maximum operation time T2 in FIG. 7 is a time related to the solar irradiance time, and may be a fixed time obtained by experiments. However, since it is related to the solar irradiance time, winter is short and summer is long. In this embodiment, the correction based on the temperature detected by the outside air temperature detector 7 which changes according to the season is performed, and the basic time is set to 6
The time is a time obtained by adding a time obtained by doubling the outside air temperature (unit: minutes, up to a maximum of 60 minutes) as a correction, and thus a time between 6 hours and 7 hours.
Of course, as a correction method, there is a method in which a one-year timer is internally provided and correction is performed, or a method in which the number of times of pumping is stored and corrected therewith.

In addition, the pumping prohibition time T3 in FIG.
Since it is for preventing heat radiation from the collector 2 due to a decrease in the amount of solar radiation in the evening for 1 to 2 hours, the pumping is surely performed until the amount of solar radiation disappears at night and pumping is no longer performed. Since it is sufficient to set the pumping prohibition mode to no, about 4 to 5 hours is sufficient, but in this embodiment, 8 hours is set for safety.

Finally, the operation of supplying the hot water collected by the solar water heater 1 to the user from the hot water supply port 85 (hereinafter referred to as a hot water supply mode) will be described. In FIG. 1, when the three-way valve 5 is in the closed position (FIG. 3B) or the water-falling position (FIG. 3C), the pressure detector 83 is at or below a predetermined pressure. 8 and pressurize hot water 85
Is closed, the pump 6 stops at a predetermined pressure. Thereafter, the check valve 81 prevents the backflow to the hot water storage tank 3 and the like, and maintains the pressure. Further, when the user opens and closes the hot water supply port 85, the accumulator 82 prevents a sudden rise and fall in pressure. When the user opens the hot water supply port 85, the control unit 9 detects a decrease in water pressure or / and / or the occurrence of a water flow with the pressure detector 83 and / or the water flow detector 84, and determines that the hot water supply port 85 has been opened. 6 is driven to send hot water stored in hot water storage tank 3 to hot water supply port 85. When the user closes the hot water supply port 85, the control unit 9 detects an increase in water pressure or / and a stop of the water flow with the pressure detector 83 and / or the water flow detector 84, determines that the hot water supply port 85 is closed, and determines the pressure. After confirming the rise in the predetermined pressure of the detector 83, the driving of the pump 6 is stopped.

The fact that the user opens the hot water supply port 85 and desires hot water supply means that the water supply mode, the heat collection mode,
It is necessary to immediately execute the hot water supply mode even in the middle of the falling water mode and the pumping prohibition mode.Basically, the hot water supply mode is also performed in the middle of each of the pumping mode, the heat collection mode, the falling water mode, and the pumping prohibition mode. Do. However, in the pumping mode in which the position of the three-way valve 6 is a pumping position (FIG. 3A) and a position with the smallest opening area (FIG. 3D), which is a case where it is impossible to perform in parallel. When the user opens the hot water supply port 85, the water pumping mode is temporarily interrupted and the hot water supply mode is given priority. Therefore, in step 42 of FIG. 6, the control unit 9 keeps the three-way valve 5 at the water-falling position (FIG. 3C) because the outside-air temperature detector 7 remains in the pumping mode after the water-falling mode ends. And the time during which pumping is not started according to the detection temperature condition of the collector temperature detector 23 (steps 11 to 14 in FIG. 4).
This is because the hot water supply mode can be given priority during that time. Of course, after step 43 in FIG. 6, the three-way valve may be set to the closed position (FIG. 3B) without being kept at the water drop position (FIG. 3C).

As described above, the solar water heater and the control method thereof according to the embodiment have the following functions. a. In claim 1, the normal pumping mode, the heat collecting mode, and the falling water mode are determined only by the outside air temperature detector and the collector temperature detector, and the solar heat can be collected in the hot water storage tank, and
Pumping is not performed at a temperature where there is a risk of freezing by the outside air temperature detector as described in the pumping mode of FIG. 4. Even in the heat collection mode of FIG. 5, pumping is temporarily performed and the outside air temperature may freeze. If the temperature drops to a certain temperature, it has a control unit that executes water drop at that point, thereby preventing the solar water heater from freezing at the time of low temperature in winter etc. . b. In claim 2, a normal pumping mode, a heat collecting mode, and a falling water mode are determined only by the outside air temperature detector and the collector temperature detector, and solar heat can be collected in the hot water storage tank, and
As in the description of the pumping mode in FIG. 4, pumping is not performed at a temperature at which there is a risk of freezing by the outside air temperature detector. Even in the heat collection mode in FIG. If the temperature drops to a temperature at which there is a risk of freezing, water is dropped at that point, thereby preventing the solar water heater from being damaged by freezing at a low temperature in winter or the like and becoming unusable, and excellent in use performance. c. According to the third aspect of the present invention, in addition to the operation of the above a, the pumping of the collector is prohibited and the pumping is performed to the collector during the time when the amount of solar radiation in the evening decreases, as described in the pumping prohibited mode of FIG. The heat collection performance is improved by having the control unit for preventing heat radiation. d. According to the fourth aspect, in addition to the operation of b, the pumping of the collector is prohibited during the time when the amount of solar radiation decreases in the evening as described in the pumping prohibition mode of FIG. Preventing heat dissipation improves heat collection performance. e. In claim 5, in addition to the effect of the a or c,
By having the control means for controlling the three-way valve in step 21 and step 22 in FIG. 4, it is possible to prevent overflow from the air venting means, and to prevent wasteful water and the amount of heat collected from being released. Is improved. f. In claim 6, in addition to the action of b or d,
By controlling the three-way valve of step 21 and step 22 of FIG. 4, overflow from the air venting means is prevented,
As a result, wasteful water and the amount of heat collected are prevented from being released, so that the economic efficiency and heat collecting performance are improved.

[0031]

According to the present invention, there is provided a solar water heater and a control method therefor which can perform freezing prevention operation at a low temperature in winter or the like and can collect heat effectively without increasing the number of temperature detectors as compared with the conventional example. It can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a solar water heater of the present invention.

FIG. 2 is a configuration diagram of a control unit, a detection unit, and a control target of the present invention.

3A and 3B are schematic diagrams of a three-way valve and a connection system thereof according to the present invention, wherein FIG. 3A is a pumping position, FIG. 3B is a closed position, FIG. 3C is a water drop position, and FIG. .

FIG. 4 is a flowchart of a pumping mode according to the present invention.

FIG. 5 is a flowchart of a heat collection mode of the present invention.

FIG. 6 is a flowchart of a falling water mode according to the present invention.

FIG. 7 is a flowchart of a pumping prohibition mode of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solar water heater 2 collector 3 hot water storage tank 4 common pipe 5 three-way valve 6 pump 7 outside air temperature detector 8 hot water supply pipe 9 control unit 21 air release means 22 collector water level detector 23 collector temperature detector 31 upper connection port 32 lower connection port 41 Dropping water pipe 42 Pumping pipe 44 Water supply pipe 45 Water supply valve 46 Hot water tank water level detector 81 Check valve 82 Accumulator 83 Pressure detector 84 Water flow detector 85 Hot water supply 91 Pumping determination means 92 Heat collection determination means 93 Waterfall determination means 94 Maximum operation Judgment means 95 Pumping prohibition means 96 Three-way valve control means

Claims (6)

[Claims] 1. A collector that collects solar heat and raises the temperature of water inside, a hot water storage tank that is lower than the collector and stores water to be sent to the collector and water heated by the collector.
Air bleeding means at the top of the collector for discharging air from the collector; a collector water level detector at the top of the collector to determine that there is water in the collector;
A pipe connecting the collector and the hot water tank, a three-way valve for switching the connection of the pipe to a connection port provided at an upper part and a lower part of the hot water tank, and a three-way valve and a pipe from a lower connection port of the hot water tank. In a solar water heater having a pump for pumping water to the collector and a collector temperature detector for detecting the temperature of water contained in the collector, an outside air temperature detector for detecting a temperature of outside air near the solar water heater A solar water heater comprising a controller for determining whether water contained in the hot water tank is sent to the collector by the pump by the collector temperature detector and the outside air temperature detector. 2. A collector that collects solar heat and raises the temperature of water inside the collector, a water storage tank that is lower than the collector and stores water to be sent to the collector and water heated by the collector.
Air bleeding means at the top of the collector for discharging air from the collector; a collector water level detector at the top of the collector to determine that there is water in the collector;
A pipe connecting the collector and the hot water tank, a three-way valve for switching the connection of the pipe to a connection port provided at an upper part and a lower part of the hot water tank, and a three-way valve and a pipe from a lower connection port of the hot water tank. In a solar water heater having a pump for pumping water to the collector and a collector temperature detector for detecting the temperature of water contained in the collector, an outside air temperature detector for detecting a temperature of outside air near the solar water heater A method for controlling a solar water heater, characterized in that the collector temperature detector and the outside air temperature detector determine whether water contained in the hot water tank is sent to the collector by the pump. 3. The pump according to claim 1, wherein the control unit detects pumping by the collector temperature detector and the outside air temperature detector, and detects the collector temperature detector after starting the heat collection after the pumping. Heat collection determining means for determining that the temperature rises for a first predetermined time and continuing heat collection at the collector; and whether the heat collection determining means determines a decrease in the detected temperature with the collector temperature detector. Or, when the first predetermined time has elapsed from the start of heat collection, the three-way valve is switched to drop the water into the hot water storage tank. A maximum operation determining means for repeatedly performing heat and water drop, and a water drop when the detected temperature of the collector temperature detector falls during the first predetermined time during heat collection after the second predetermined time has elapsed. And then the pumping determination means A solar water heating device, comprising: a pumping prohibition unit that stops pumping water to the collector for a third predetermined time even if it is determined to be nook. 4. The control method according to claim 2, wherein pumping is performed by the collector temperature detector and the outside air temperature detector, and after the heat collection is started after the pumping, the detected temperature of the collector temperature detector is set to a first temperature. It is determined that the temperature rises during the predetermined time, and the heat collection at the collector is continued, and if the detected temperature of the collector temperature detector falls during the first predetermined time or the first predetermined time has elapsed. In this case, the three-way valve is switched to drop water into the hot water storage tank, and pumping, heat collection, and water dropping are repeated for a second predetermined time from the first pumping start, and the second predetermined time is set. If the detected temperature of the collector temperature detector falls during the first predetermined time during the heat collection after the elapse, water is dropped, and even if it is determined that water can be pumped, the collector is transferred to the collector for the third predetermined time. Solar water heater characterized by stopping pumping of water Control method. 5. Immediately after the start of pumping of pumping water from the hot water tank to the collector by the pump, the flow path of the three-way valve is connected to the hot water tank lower connection port and the collector so as to be in an open position, The solar water heater according to claim 1 or 3, further comprising a three-way valve control unit that moves the opening area of the flow path of the three-way valve after the fourth predetermined time has elapsed from the start of pumping. 6. Immediately after the pumping of pumping water from the hot water tank to the collector with the pump, the three-way valve is connected to the hot water tank lower connection port and the collector so as to be in an open position, The method according to claim 2 or 4, wherein the three-way valve is moved in a direction in which the opening area of the flow path decreases after a lapse of a fourth predetermined time from the start of pumping.