JPH02623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar heat collection system that forcibly circulates a liquid as a heat medium within a sealed piping circuit, and specifically solves the problems of boiling when the heat medium overheats and freezing during cold seasons. This is related to a solar heat collection system.

There are two main types of heat collection piping circuits for solar heat collection systems: open to atmosphere type and closed type. The open system eliminates the heat medium in the heat collector when the pump is stopped, and easily solves the problem of blowouts and freeze damage of the heat collector due to overheating of the heat collector and boiling of the heat medium. Can be done. However, this open system requires a large amount of pump power, and the heating medium often comes into contact with fresh air, resulting in problems such as corrosion of the piping and deterioration of the heating medium. A closed-type heat collection system is a solution to this problem. In this sealed system, the freezing problem can be solved by using antifreeze as a heat medium, but the problem of boiling still remains.

The object of the present invention is to eliminate the above-mentioned disadvantages, and to combine open and closed systems in such a way that only their advantages are obtained, and to provide a suitable structure for preventing boiling of the heating medium during overheating and freezing during cold periods. The aim is to provide a solar heat collection system.

The present invention provides a solar heat collection system in which a heat medium made of antifreeze is circulated between a solar heat collector and a heat radiator (e.g., a heat exchanger, a radiator, a heat storage unit, etc.), in which the heat collector is placed in a horizontal plane. An absorber tank is installed on the downstream side of the collector between the collector and the heat dissipation part, and is arranged inclined or vertically. It is characterized in that a free surface of the heat medium is always formed on the lower side of the lower inlet portion.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an example of an absorber tank applied to the solar heat collection system according to the present invention. The absorber tank 1 includes a chamber 2 having a predetermined volume, and the chamber 2 has a larger cross-sectional area than the upper and lower inlet and outlet pipes.

FIG. 2 is a diagram showing the configuration of an example of the solar heat collection system according to the present invention. Input side 5 of heat dissipation section 4
The outlet end of the piping constituting the is connected to the inlet end 8 of a heat collector 7 via a pump 6. Outlet end 9 of heat collector 7
is connected to the inlet end of the piping on the input side 5 of the heat radiating section 4 via the absorber tank 1. The collector 7 can be inclined or vertical as shown. This heat collection system therefore constitutes a closed system. This heat collection system is filled with antifreeze as a heat medium. The amount of heat transfer medium is determined such that a free surface 10 of the heat transfer medium is formed in the absorber tank 1 when the pump 6 is stopped, as shown in FIG. Further, the absorber tank 1 is arranged below the inlet end 8 of the heat collector 7 in the vertical direction. This absorber tank 1
The internal volume of the pump 6 is set so that the amount of heat medium in the absorber tank when it is stopped is larger than the amount of heat medium that fills the heat collector when it is in operation. A surface 10 is formed.

The operation of the solar heat collection system having such a configuration will be explained. As shown in FIG. 3, when the pump 6 is stopped, the heat medium in the heat collector 7 falls by its own weight from the inlet end along the gradient of the heat collector, and the heat medium falls into the absorber tank 7.
It drops to almost the same level as the free surface that forms inside. Since the absorber tank 1 is provided at a lower position than the heat collector, no heat medium remains in the heat collector 7 when the pump 6 is stopped. When the pump 6 is in operation, as shown in FIG. 4, the heat medium flows into the heat collector 7 due to the pressure of the pump 6 and is heated by solar heat.
It flows out from the outlet end 9 and falls into the absorber tank 1. As described above, since a free surface of the heat medium is always formed in the absorber tank, the heat medium is once accommodated in the absorber tank and then flows into the heat radiating section 4. The heat dissipation section transfers the heat of this heat medium to the output side.

Note that since the above-mentioned system is of a closed type, freezing in the cold season can be prevented by using antifreeze as a heat medium as described above. Furthermore, if an inert gas is sealed in the gas phase within this closed system, deterioration of the heat medium within the system and corrosion of the piping can be further reduced.

When the heat medium falls from the heat collector 7 into the absorber tank disposed below, air bubbles are generated, which may accumulate in the suction section of the pump, causing the pump to stop. To prevent this, the absorber tank is made vertically longer as shown in FIG. 5, and a gas-liquid separator 12 is installed in the absorber tank as shown in FIG. It is advantageous to avoid downstream spills. Furthermore, the amount of air bubbles generated in the tank can be reduced by providing an inlet/outlet for the heat medium to the absorber tank on the side of the absorber tank.

As is clear from the above explanation, according to the solar heat collection system of the present invention, an absorber tank is provided so that the heat medium does not remain in the heat collector when the pump that operates this system is stopped. It has such excellent effects.

(i) If there is a risk that the heat medium may boil due to overheating of the heat collector, the pump can be stopped and all of the heat medium in the heat collector can be collected into the absorber tank. The safety of the solar heat collection system is maintained by avoiding the pressure increase.

(ii) Since antifreeze is used as a heat medium, freezing damage to the heat collector and its surrounding areas can be prevented in cold weather without the need for special freezing measures.

(iii) Since the piping is sealed, there is less deterioration of the heat medium and less corrosion of the piping.

(vi) Since the absorber tank functions as a check valve to prevent heat loss due to thermosiphon during stoppage, it is not necessary to separately arrange a check valve. Therefore, the system can be simplified.

(v) The pump head only needs to be from the free surface inside the absorber tank to the top of the collector, and energy savings can be achieved by requiring less power than in a completely falling type.

(vi) In a closed system, an expansion tank is required to absorb the thermal expansion of the heat medium, but the absorber tank of the present invention also serves as an expansion tank.
An expansion tank is no longer required.

(vii) By installing a temperature sensor in the heat collector and controlling the operation of the pump according to the detected temperature, boiling and freezing can be completely automatically prevented.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an example of an absorber tank applied to the solar heat collection system according to the present invention, FIG. 2 is a diagram showing the configuration of an example of the solar heat collection system according to the present invention, and FIG. FIG. 2 is a diagram showing the free surface of the heat medium in the absorber tank when the system is stopped; FIG. 4 is a diagram illustrating the operation of the system shown in FIG. 2 when it is in operation;
FIG. 5 is a diagram showing the configuration of another example of the absorber tank applied to the solar heat collection system according to the present invention, and FIG. 6 is a diagram showing the configuration of still another example of the absorber tank applied to the solar heat collection system according to the present invention. FIG. 1...Absorber tank, 2...Chamber, 4...Heat radiation part,
6... Pump, 7... Heat collector, 10... Free surface of heat carrier.

Claims (1)

[Claims] 1 In a solar heat collection system in which a heat medium made of antifreeze is circulated between a solar heat collector and a heat radiating part by a pump, the heat collector is arranged at an angle or perpendicular to the horizontal plane, and the heat collector An absorber tank is provided to store the heat medium on the downstream side of the heat collector between the pump and the heat radiation section, and when the pump is stopped, the heat medium in the heat collector is discharged outside the heat collector and collected in the absorber tank. A solar heat collection system characterized in that the free surface of the heat medium is always formed below the lowest inlet part of the heat collector in the absorber tank.