JPS5917338B2 - solar heat collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention connects a solar collector and a heat storage tank with piping, and a circulation pump is interposed in the piping, so that the heat heated in the collector by the operation of the pump is This invention relates to a solar heat collector that stores a medium in a heat storage tank.

Generally, as shown in FIG. 1, in such a solar heat collecting device, a heat collector 1 and a heat storage tank 2 are connected through a pipe 3, and a circulation pump 4 is interposed in the pipe 3. The system is equipped with a high-temperature side sensor 5 that detects the temperature of the heat medium (hereinafter referred to as water) in the heat collector 1 and a low-temperature side sensor 6 that detects the water temperature in the heat storage tank 2, as shown in Fig. 2. This is done by a control device 7' that operates according to the temperature difference between the two sensors 5 and 6.

Note that 8 is a water supply pipe, and 9 is a hot water supply pipe.

In other words, [-high temperature side sensor 5 temperature> low temperature side sensor 6 temperature j
Under these conditions, and when the temperature difference is △T1 or more, operate the pump 4, and the temperature difference △T2 (△T, > △T2)
The pump 4 is stopped when the temperature is below.

The reason why the temperature difference between on and off times is changed is to prevent the pump 4 from starting and stopping frequently.

However, as shown in FIG. 3, in this method, when hot water is supplied when there is no solar radiation, such as at night, cold water is replenished into the heat storage tank 2, and the low-temperature side sensor 6 installed at the bottom of the heat storage tank 2 detects the hot water. The temperature decreases, and the temperature difference between both sensors 5 and 6 becomes △T
When the temperature exceeds 1, the pump 4 operates, the hot water remaining in the heat collector 5 is stored in the heat storage tank 2, the cold water in the lower part of the heat storage tank 2 is sent to the heat collector 1, and the difference between the two sensors is When the temperature becomes below ΔT2, the pump 4 stops.

Thereafter, when the temperature of the water supplied to the heat storage tank 2 is low and the outside air temperature is high, the temperature inside the heat collector 1 gradually rises, and when the temperature difference reaches ΔT1 or more, the circulation pump 4 starts operating.

In this case, the amount of heat collected is small, and the temperature difference immediately becomes ΔT2 or less, and the circulation pump 4 stops.

Since this process is repeated thereafter, the circulation pump 4 operates intermittently even though there is no sunlight, wasting power due to the small amount of heat collected, and causing discomfort to the customer.

The present invention has been made in view of the above-mentioned fact, and the circulation pump is constructed by taking the logical product of the heat medium temperature of the heat collector being a certain value or more and the heat medium temperature difference between the heat collector and the heat storage tank being more than a certain value. The purpose of this system is to prevent wasteful starting and stopping of the circulation pump in conditions where there is no sunlight, such as at night, without reducing heat collection efficiency.

Hereinafter, the present invention will be applied to the solar heat collector shown in FIG. 1 and explained based on the drawings.

FIG. 4 shows the control device 7 used in the present invention, which includes a constant temperature thermo circuit 10, a differential temperature thermo circuit 11, and a logic circuit 1.
2, a pump drive circuit 13, and a feedback circuit 14 for differential setting, and 15 and 16 are bus bars to which DC power (not shown) is supplied.

The constant temperature thermo circuit 10 has a resistor 17 forming a bridge.
to 19, a high temperature side sensor 5 that detects the water temperature of the heat collector 1, and an output point A.

It is equipped with an amplifier 20 for comparing the potential of C.

The temperature difference thermo circuit 11 has a resistor 17゜2 that constitutes a bridge.
1. High temperature side sensor 5, low temperature side sensor 6 that detects the water temperature of heat storage tank 2, and partial pressure resistance 22.2 of low temperature side sensor 6
3, and an amplifier 24 for comparing the potentials of output points A and B.

The logic circuit 12 receives the outputs of the amplifiers 20 and 24 as input, and its own output is connected to the amplifier 2 via the diode 25.
It is equipped with an AND circuit 26 which is fed back to the 0 side input.

The pump drive circuit 13 includes a transistor 27 that receives the output of the AND circuit 26 as an input, and a relay R that receives the output of the transistor 27.

The feedback circuit 14 includes a transistor 29 that inserts a resistor 28 in parallel with the resistor 21 when the transistor 27 is turned on.

Note that 30 is a relay switch that closes when the relay R is energized to connect the circulation pump 4 to an AC power source (not shown).

Incidentally, the sensor 5.6 uses a thermistor having negative temperature-resistance characteristics.

The operation of the control device 7 will be explained with reference to FIG.

In the constant temperature thermocircuit 10, when the temperature detected by the high temperature side sensor 5 of the heat collector 1 is higher than T3, the potential at point 0 becomes higher than the potential at point A, and the amplifier 20 outputs a high voltage.

In the differential temperature thermo circuit 11, when the temperature detected by the high temperature side sensor 5 is higher than the temperature detected by the low temperature side sensor 6 of the heat storage tank 2 by 611 or more, the potential at point B becomes higher than the potential at point A, and the amplifier 24 turns to a high voltage. Emits output.

When both amplifiers 20 and 24 output a high voltage, the AND circuit 26 of the logic circuit 12 outputs a high voltage, the transistor 27 is turned on, the relay R is energized, and the circulation pump 4 is started. .

Since the high voltage output of the AND circuit 26 is fed back to the input on the amplifier 20 side, the input on the amplifier 20 side is then fed back to the amplifier 20.
is held at a high voltage even if it produces a low voltage output.

Furthermore, when the transistor 27 is turned on, the transistor 29 of the feedback circuit 14 is also turned on, the resistor 28 is inserted in parallel with the resistor 21, and the potential at point B increases.

Therefore, the temperature difference thermo circuit 11 has a temperature difference △T2 (△T
The amplifier 24 maintains the high voltage output until the difference temperature becomes smaller than ΔT1), and when the difference temperature becomes smaller than ΔT2, the amplifier 2
4 and AND circuit 26 provide a low voltage output and transistor 27 turns off, stopping circulation pump 4.

At this time, the feedback of the AND circuit 26 disappears, and the feedback circuit 1
The transistor 29 of No. 4 is also turned off.

Therefore, when there is sunlight, the temperature detected by the high temperature side sensor 5 of the heat collector 1 exceeds the constant temperature T3 (for example, 30°C), and the temperature detected by the high temperature side sensor 5 is equal to the temperature detected by the low temperature side sensor 6. If it is higher than 611, the control device 7 controls the circulation pump 4.
is started, and the hot water in the heat collector 1 is stored in the heat storage tank 2.

Then, the cold water in the lower part of the heat storage tank 2 is sent to the heat collector 1, and even if the temperature detected by the high temperature side sensor 5 becomes lower than T3, the circulation pump 4 continues to operate until the temperature difference becomes smaller than ΔT2. In addition to good heat collection, the circulation pump 4
There is no risk of so-called hunting operation in which the power is turned on and off frequently.

On the other hand, in a state where there is no sunlight such as at night, even if the heat collector 1 is warmed by the outside air, the circulation pump 4 will start unless the temperature detected by the high temperature side sensor 5 exceeds the constant temperature T3 and the temperature difference is 611 or more. This prevents wastage of power and does not cause discomfort to customers.

That is, as shown in FIG. 6, when hot water is being supplied and hot water higher than the constant temperature T3 still remains in the heat collector 1, cold water is replenished into the heat storage tank 2, and the temperature detected by the low-temperature side sensor 6 increases. When the temperature difference reaches ΔT1 or more, the circulation pump 4 is started and the hot water in the heat collector 1 is collected into the heat storage tank 2.

When the temperature difference eventually becomes smaller than ΔT2, the circulation pump 4 stops.

Thereafter, the water in the heat collector 1 is gradually heated when the outside temperature is high, but since there is no sunlight, it can reach a constant temperature T3,
The circulation pump 4 does not start even if a temperature difference of ΔT1 or more occurs.

As described above, the present invention provides a system in which a heat collector and a heat storage tank are connected through piping, and a circulation pump is interposed in the piping, and when the heat medium temperature of the heat collector exceeds a certain value, The system is equipped with a control device that starts the circulation pump based on the logical product of the heat medium temperature difference between the heat exchanger and the heat storage tank, which is greater than a certain value, allowing efficient heat collection operation without any problems in the presence of solar radiation. The circulation pump can be prevented from starting when there is no sunlight, such as at night, so that power can be saved and there is no risk of causing discomfort to customers or shortening the life of the circulation pump.

[Brief Description of the Drawings] Fig. 1 is a system diagram of a solar heat collector to which the present invention is applied, Fig. 2 is a temperature characteristic diagram showing an example of starting and stopping a circulation pump by a conventional control device, and Fig. 3 is a system diagram of a solar heat collector to which the present invention is applied. An explanatory diagram of the operation of the conventional device; FIG. 4 is an electric circuit diagram showing an example of the control device used in the present invention;
FIG. 5 is a temperature characteristic diagram showing examples of starting and stopping of the circulation pump by the control device used in the present invention, and FIG. 6 is an explanatory diagram of the operation of the device of the present invention. 1... Heat collector, 2... Heat storage tank, 3...
...Piping, 4...Circulation pump, 5...
...High temperature side sensor, 6...Low temperature side sensor, 7.
·····Control device.

Claims (1)

[Claims] 1. In the case where the heat collector and the heat storage tank are connected through piping and a circulation pump is installed in the piping, if the heat medium temperature of the heat collector exceeds a certain value, the heat of the heat collector and the heat storage tank is A solar heat collector equipped with a control device that starts a circulation pump by calculating the logical product of a medium temperature difference equal to or greater than a certain value.