JP2013145071A - Solar heat collecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar heat collecting system that can stably operate in a wide temperature range with a simple configuration.SOLUTION: A solar heat collecting system 100 includes: a first hollow transparent glass plate 21, solar light passing therethrough, an inner part thereof being vacuumed to suppress a heat transfer; a selective absorbing film attached outside the first hollow transparent glass plate 21; a heat collecting device 26 attached to a surface opposite to the first hollow transparent glass plate 21 of the selective absorbing film and for heat collection of solar heat; and a closed-loop circulation system 60 for circulating heating medium in the heat collecting device 26.

Description

  The present invention relates to a structure of a heat collection system using a solar heat collector.

  It is underway to collect solar heat and use the heat to heat the heating medium and extract the energy. As a device for collecting solar heat into a high-temperature heat medium, a heat collector is placed on a high tower and the heat medium is heated to a high temperature by collecting sunlight using about 1000 plane mirrors. There were a tower method and a method in which a heat collecting tube was arranged at the focal position of a cylindrical parabolic mirror and a heat medium flowing through the heat collecting tube was heated. However, these methods have a problem that the whole system becomes large and a special mirror is required.

  For this reason, a solar collector with a wavelength-selective selective absorption film that absorbs energy in the wavelength band centered on visible light is housed in a vacuum casing inside, and sunlight enters. Solar collectors have been proposed with transparent glass windows on the surface. In this solar heat collector, a method has been proposed in which the heat collection efficiency is improved by reducing the heat radiation loss due to heat transfer of air by making the inside vacuum, and reducing the radiation loss in the far infrared region by the selective absorption film. (For example, refer to Patent Document 1).

JP 2002-115717 A

  In the solar heat collector, when air enters the vacuum casing, heat dissipation loss due to heat transfer of air increases, and heat collection efficiency decreases. For this reason, the connection part of a casing and window glass is joined so that it may become airtight with adhesive agents, such as an epoxy resin. However, since the solar heat collector is installed outdoors, the adhesive deteriorates over time due to temperature changes and ultraviolet rays, and there is a problem that air enters the casing during the period of use and the heat collection efficiency decreases.

  In addition, when the medium flowing through the heat medium does not absorb solar heat such as at night, the temperature drops to the atmospheric temperature, and during the daytime when the solar heat is absorbed, the temperature becomes 100 ° C. or higher. When water or the like is used as the refrigerant, a method of applying pressure to the refrigerant is often used so that the refrigerant does not boil even when the temperature of the refrigerant becomes 100 ° C. or higher by absorbing solar heat. However, if the boiling of the refrigerant is to be suppressed by pressurization, it is necessary to make the heat collecting tube into a pressure-resistant structure, which causes a problem that the heat collecting efficiency is lowered, the weight is increased, and the cost is increased. Further, when the temperature of the refrigerant drops to below freezing at night and the refrigerant freezes, there is a problem in that the heat collecting tube is damaged due to expansion of the volume of the refrigerant. For this reason, there existed a problem that a solar heat collection system cannot be installed in cold districts, such as a polar region, and a high temperature zone, for example.

  It is an object of the present invention to provide a solar heat collection system that can provide a solar heat collection system that can be stably operated in a wide temperature range with a simple configuration.

  A light transmissive heat insulating member that transmits sunlight and suppresses heat conduction, and is attached to the outside of the light transmissive heat insulating member, and selectively absorbs the heat of sunlight incident through the light transmissive heat insulating member. A selective absorption film that suppresses thermal radiation, a heat collector that is attached to the surface of the selective absorption film opposite to the light-transmitting heat insulating member, and that collects solar heat, and a circulation that circulates the heat medium through the heat collector A solar heat collecting system, wherein the translucent heat insulating member is a hollow transparent glass flat plate having a vacuum inside.

  In the solar heat collecting system of the present invention, the system includes a tank in which the heat storage liquid is stored, and the circulation system includes a heater that heats the heat storage liquid stored in the tank by the circulating heat medium, and the tank. And a heater that raises the temperature of the feed water by the heated stored heat storage liquid, and the circulation system is preferably a closed loop.

  In the solar heat collection system of the present invention, the circulation system is preferably equipped with a circulation pump that is driven by a solar cell and circulates the heat medium, and the heat medium is at least the heat collector. It is also preferable to circulate between a steam turbine that drives the generator and a boiler that supplies driving steam to the steam turbine.

  The present invention has an effect that it is possible to provide a solar heat collecting system capable of stable operation in a wide temperature range with a simple configuration.

It is explanatory drawing which shows a structure at the time of attaching the solar heat collecting system of embodiment of this invention to a building. It is explanatory drawing which shows the system | strain of the solar thermal collection system of embodiment of this invention. It is sectional drawing which shows the structure of the solar-heat collector used for the solar-heat collection system of embodiment of this invention. It is sectional drawing which shows the structure of the other solar-heat collector used for the solar-heat collection system of embodiment of this invention. It is a systematic diagram which shows the structure at the time of using the solar heat collection system of embodiment of this invention for an electric power generation system.

  As shown in FIG. 1, a solar heat collection system 100 according to an embodiment of the present invention is installed on a roof 11 of a building 10, and receives a solar heat collector 20 that receives sunlight 15, and circulates a heat medium through the solar heat collector 20. A circulation system 60, a circulation pump 50 provided in the circulation system 60 to circulate the heat medium to the circulation system 60, a solar cell 30 that is a drive source of the circulation pump 50, a tank 40 that stores heat storage liquid, and a tank 40 And a heater 70 that heats the heat storage liquid by a heat medium that circulates in the circulation system 60 and a heater 80 that heats the water supplied to the water supply system 90 provided in the tank 40. .

  The heat medium circulating in the circulation system 60 is heated by the solar collector 20, becomes a high-temperature heat medium, flows into the heater 70 of the tank 40, and heats the heat storage liquid 45 in the tank 40 through the heater 70 of the tank 40. . On the other hand, the low temperature water supplied from the water supply pipe 91 of the water supply system 90 is heated by the heater 80 in the tank 40 and supplied as hot water from the hot water pipe 92 to the facilities such as the bath 12 through the hot water outlet 93 in the building. Is done.

  As shown in FIG. 2, the solar collector 20 of the solar heat collection system 100 of this embodiment includes a serpentine-like heat collector 26 through which a heat medium flows on the surface, and the heat collector 26 includes a circulation system 60. A surge tank 27 to which a relief valve 28 is attached to prevent the internal pressure from exceeding a certain pressure is connected. The circulation pump 50 includes a pump body 51 and a drive motor 52, and the drive motor 52 is driven by electric power supplied from the solar cell 30. The solar cell 30 is a combination of a plurality of solar cell panels 31. The tank 40 for storing the heat storage liquid 45 has a double structure of an inner casing 41 and an outer casing 42, a vacuum layer 43 is provided between the casings 41, 42, and the outside of the outer casing 42 is insulated. Covered by a material 44. A relief valve 48 is attached to the upper part of the tank 40 so that the pressure inside the tank 40 does not exceed a certain pressure. Both the heater 70 and the heater 80 are heat exchangers in which heat transfer tubes are arranged in a serpentine shape.

  As shown in FIG. 3, the solar collector 20 has a first hollow transparent glass flat plate 21 and a first hollow transparent glass flat plate 21, which are translucent heat insulating members that transmit sunlight 15 and suppress heat conduction. A vacuum casing 35 made of a metal material such as iron attached to the side of the back surface 24 opposite to the front surface 22 receiving the solar light 15, and a selective absorption film 25 attached to the internal space 36 of the vacuum casing 35. , And a heat collector 26 attached to a surface opposite to the back surface 24 of the selective absorption film 25. As described above, the heat collector 26 is composed of a serpentine pipe through which a heat medium flows, and the heat medium inlet pipe 61 and the heat medium outlet pipe 62 of the circulation system 60 are connected to each other. The hollow portion 23 inside the first hollow transparent glass flat plate 21 is in a vacuum. The first hollow transparent glass flat plate 21 is manufactured, for example, by heating to a high temperature of about 500 ° C. and exhausting the air adsorbed on the glass with a vacuum pump, followed by sealing. The vacuum casing 35 is attached to the side surface of the first hollow transparent glass flat plate 21 so that the internal space 36 is sealed by an adhesive or glass welding. After the vacuum casing 35 is attached, the internal space 36 is evacuated by exhausting air with a vacuum pump or the like. The selective absorption film 25 suppresses radiation of sunlight 15 and effectively collects heat from sunlight. The surface of the selective absorption film 25 is disposed so as to provide a gap between the lower surface 24 of the first hollow transparent glass flat plate 21.

  The operation of the solar heat collection system 100 configured as described above will be described. As shown in FIG. 3, when receiving sunlight 15, sunlight 15 enters from the front surface 22 of the first hollow transparent glass plate 21 of the solar heat collector 20, passes through the vacuum hollow portion 23, and from the back surface 24. The light enters the selective absorption film 25 provided in the internal space 36 of the vacuum casing 35. The selective absorption film 25 suppresses radiation from the surface of the sunlight 15 and effectively absorbs the heat of the sunlight 15. Then, the solar heat absorbed by the selective absorption film 25 moves to the heat medium flowing inside the heat collector 26 and raises the temperature of the heat medium. Moreover, since the hollow part 23 is a vacuum in the 1st hollow transparent glass flat plate 21, it suppresses that the heat | fever of the selective absorption film | membrane 25 and the heat collector 26 is dissipated outside by heat conduction. Accordingly, the solar heat from the sunlight 15 is efficiently transferred to the heat medium of the heat collector 26 due to the suppression of the radiant heat by the selective absorption film 25 and the suppression of the heat conduction by the first hollow transparent glass plate 21. Effectively increase the temperature of the medium. The heat medium does not freeze at about 30 ° C. below zero and does not boil even when the temperature exceeds 100 ° C., for example, may be an antifreeze such as ethylene glycol or a special heat medium that does not boil to about 250 ° C. Good. In this way, a heat medium that does not boil even when the solar heat is collected is used.

  In the daytime when the sun goes out, the solar cell 30 shown in FIG. 1 also receives sunlight 15 and supplies the electric output to the drive motor 52 of the circulation pump 50. Therefore, the circulation pump 50 rotates and the heat medium circulates. Circulate system 60. Then, the heat medium flows from the heat medium outlet pipe 62 to the heater 70 in the tank 40 and heats the heat storage liquid 45 such as water stored in the tank 40. On the other hand, the low-temperature water supply flows into the heater 80 from the water supply pipe 91, exchanges heat with the heated heat storage liquid 45, rises in temperature, and is supplied from the hot water pipe 92 to the hot water supply port 93 in the building.

  The heat medium having fallen in temperature leaves the heater 70 of the tank 40, is pressurized by the circulation pump 50, and returns to the solar collector 20 disposed on the roof 11 to be heated again. Then, when the sun goes down at night, the supply of electric power from the solar cell 30 is stopped, so that the heat collection by the solar heat collector 20 is stopped and the drive motor 52 of the circulation pump 50 is stopped to circulate the heat medium. Stops. At night time, since there is no heat collection by the solar heat collector 20, the temperature of the heat medium in the circulation system 60 decreases, and when the outside air falls below freezing point, the temperature of the heat medium also falls below freezing point. However, the heat medium is not frozen because it uses antifreeze or a special heat medium that does not freeze at low temperatures.

  Further, since the heat medium does not boil even when the solar heat is collected, the pressure of the circulation system 60 does not increase, and the solar heat can be collected efficiently without increasing the pressure resistance of the circulation system 60. . And even in an area where the atmospheric temperature is high, there is little increase in pressure, and stable operation can be performed. Further, since the heat medium only circulates in the closed loop circulation system 60, the system can be configured by using a small amount of a special heat medium, and the heat collection efficiency can be reduced while suppressing the cost of the solar heat collection system 100. High and stable operation is possible.

  As described above, the solar heat collection system 100 of the present embodiment has an effect that it is possible to provide a solar heat collection system that can be stably operated in a wide temperature range with a simple configuration.

  Next, the configuration of another solar collector 20 will be described with reference to FIG. In the solar heat collector 20 shown in FIG. 4, the selective absorption film 25 and the heat collector 26 are arranged in the hollow portion 33 of the second hollow transparent glass flat plate 32 in place of the vacuum casing 35 of the solar heat collector 20 described in FIG. Is. The second hollow glass flat plate 32 is overlapped and attached to the surface of the back surface 24 opposite to the front surface 22 that receives the sunlight 15 of the first hollow transparent glass flat plate 21. Similarly to the above, for example, after heating to a high temperature of about 500 ° C. and exhausting air adsorbed on the glass with a vacuum pump, sealing is performed. The second hollow transparent glass flat plate 32 is preferably attached in close contact with the back surface 24 of the first hollow transparent glass flat plate 32, but there may be a slight gap. Even when the solar heat collecting system 100 described with reference to FIG. 1 and FIG. 2 is configured using the solar collector 20 configured as in the present embodiment, the same effects as those of the embodiment described above are obtained.

  Next, a case where the solar heat collector 20 described with reference to FIGS. 3 and 4 is applied to the power generation system 200 will be described with reference to FIG. As shown in FIG. 5, a power generation system 200 includes a steam turbine 202 that drives a generator 203, a boiler 201 that supplies driving steam to the steam turbine 202, and a condensate that returns steam expanded in the steam turbine 202 to water. And a water supply pump 205 that supplies water from the condenser 204 to the solar heat collector 20 and the boiler 201. In the power generation system 200 of the present embodiment, the heat medium is water. The water that has entered the heat collector 26 from the heat medium inlet pipe 61 of the solar collector 20 is heated by the solar collector 20 and enters the boiler 201 as high-temperature water. The boiler 201 is also supplied with water from a water supply pump 205. The feed water supplied from the feed water pump 205 is heated by the boiler 201 and then mixed with the high temperature water from the heat collector 26, and then evaporated to be supplied to the steam turbine 202 as high temperature steam. The machine 201 is rotated. The steam expanded by the steam turbine 201 is returned to water by the condenser 204 and supplied again to the solar heat collector 20 and the boiler 201. Thus, in the present embodiment, water as a heat medium circulates through the heat collector 26, the boiler 201, the steam turbine 202, and the condenser 204. Therefore, the heat collector 26, the boiler 201, the steam turbine 202, and the condenser 204 constitute a closed loop circulation system 60. The present embodiment has an effect that the solar heat collection system 100 can be used for the power generation system 200 to perform highly efficient power generation.

  In the present embodiment, it has been described that high-temperature water is put into the boiler 201 from the heat collector 26, but steam is generated by the heat collector 26 and supplied to the steam turbine 202 together with the steam generated by the boiler 201. You may comprise. Further, a large number of solar heat collectors 20 may be installed, and the steam turbine 202 may be driven by steam generated by the solar heat collector 20.

DESCRIPTION OF SYMBOLS 10 Building, 11 Roof, 12 Bath, 15 Sunlight, 20 Solar collector, 21 1st hollow transparent glass flat plate, 22 Surface, 23,33 Hollow part, 24 Back surface, 25 Selective absorption film, 26 Heat collector, 27 Surge Tank, 28, 48 Relief valve, 30 Solar cell, 31 Solar cell panel, 32 Second hollow transparent glass plate, 33 Hollow portion, 35 Vacuum casing, 36 Internal space, 40 Tank, 41 Internal casing, 42 External casing, 43 Vacuum layer, 44 Heat insulating material, 45 Thermal storage fluid, 50 Circulation pump, 51 Pump body, 52 Drive motor, 60 Circulation system, 61 Heat medium inlet pipe, 62 Heat medium outlet pipe, 70 Heater, 80 Heater, 90 Water supply System, 91 Water supply pipe, 92 Hot water pipe, 93 Hot water inlet, 100 Solar heat collection system, 200 Power generation system, 201 Boiler, 202 Steam turbine, 203 generator, 204 condenser.

Claims (4)

A transparent heat insulating member that transmits sunlight and suppresses heat conduction; and
A selective absorption film that is attached to the outside of the translucent heat insulating member, selectively absorbs heat of sunlight incident through the translucent heat insulating member, and suppresses heat radiation; and
A collector that is attached to the surface of the selective absorption film opposite to the light-transmitting heat insulating member and collects solar heat;
A circulation system for circulating a heat medium to the heat collector;
A solar heat collecting system comprising:
The translucent heat insulating member is a hollow transparent glass flat plate having a vacuum inside;
Solar heat collection system characterized by The solar heat collection system according to claim 1,
Including a tank in which the heat storage fluid is stored,
The circulation system heats the heat storage liquid stored in the tank by the circulating heat medium; and
A heater that raises the temperature of the feed water by the heated heat storage liquid stored in the tank,
The circulation system is a closed loop;
Solar heat collection system characterized by The solar heat collection system according to claim 2,
The circulation system includes a circulation pump that is driven by a solar cell and circulates the heat medium.
Solar heat collection system characterized by The solar heat collection system according to claim 1,
The heat medium circulates at least between the heat collector, a steam turbine that drives a generator, and a boiler that supplies driving steam to the steam turbine;
Solar power generation system characterized by

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