JP2003113771A - Power generating device using solar energy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generating device using solar energy as improvement of the conventional technique in which any photovoltaic power generating system has an energy conversion efficiency of as low as around 15% where the output of a solar cell depends upon the cell temperature to a great extent, while any power generating device using the solar heat requires a facility on a large scale, being suitable for a large-scale power generation system but difficult to be implemented in a relatively small application such as a dwelling house. SOLUTION: On the rear of the light receiving surface of a photovoltaic power generating cell 2, a cooling part 3 is provided having approximately the same shape as the cell 2 and furnished with a flow-through hole 6 internally, and cooling of the cell 2 is conducted by feeding a fluid cooling medium into the hole 6 in the cooling part 3, and thereby the temperature rise of the cell 2 is suppressed and the power generation efficiency is enhanced. Using together the power generation utilizing the solar heat will ensure further enhancement of the power generation efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generator using solar energy such as sunlight or solar heat.

[0002]

2. Description of the Related Art Solar energy is an inexhaustible resource and has the great advantage that even if the energy is converted, it does not emit harmful air pollutants or carbon dioxide that causes global warming. This power generation system using solar energy can be roughly classified into solar power generation and solar thermal power generation. Photovoltaic power generation is a method in which an element having an internal electric field, such as a semiconductor pn junction, is irradiated with sunlight to obtain electric energy using the obtained photovoltaic power, and is generally called a solar cell. For example, Japanese Patent Laid-Open No. 10-
Japanese Patent No. 284747 discloses a solar cell module in which the solar power generation efficiency per solar cell when the solar cell module is mounted is improved.

On the other hand, in solar thermal power generation, the energy of sunlight is stored as a heat source, and this is used to generate power. Several methods are known. One of them, for example, as disclosed in Japanese Patent Laid-Open No. 2-293562, discloses a solar power generation plant that collects solar heat with a reflecting mirror, circulates a heat medium and rotates a turbine to generate electric power. . As another method of solar thermal power generation, there is a method of generating power by thermoelectric conversion using solar heat as a heat source and a thermoelectric conversion element having a Seebeck effect. For example, as disclosed in Japanese Patent Laid-Open No. 2000-101116, a heat pipe is arranged on the back side of the light receiving surface of a solar cell panel, a Peltier cooling device is connected to the heat radiation side of the heat pipe, and the Peltier cooling device is connected to the solar system. A solar thermal power generation system is disclosed, which is driven by using electric power generated by a battery panel.

[0004]

However, among the above-mentioned solar power generation systems using solar energy, Japanese Patent Laid-Open No.
The photovoltaic power generation as disclosed in Japanese Patent Publication No. 280747 has a problem that the cost is high because it is manufactured by using a high-purity semiconductor material as a raw material, and the energy conversion efficiency thereof is about 10 to 15%. Further, the output from the solar cell is greatly influenced by the cell temperature. For example, 600W /
Even with the same solar radiation amount of m ² , the conversion efficiency of the solar cell is 14% when the temperature of the thick cell is 30 ° C. and 9% when it is 60 ° C. (Reference, Yutaka Nawada, Prediction of Annual Power Generation of Grid-Coupled Solar Power Generation System, Solar Energy, VOL.16.NO.6.1990.P.
17) In an actual solar power generation system, the higher the amount of solar radiation, the higher the temperature of the solar cell, so the efficiency of the solar cell decreases. Therefore, if the battery temperature is lowered, the conversion efficiency is increased, but water for cooling or the like is required for that purpose.

In the solar power generation plant disclosed in Japanese Patent Laid-Open No. 2-293562, since high-pressure side turbines and low-pressure side turbines are used for power generation, large-scale equipment is required, and a large-scale power generation system is required. However, there is a problem that it is difficult to implement in relatively small-scale applications such as housing. On the other hand, JP 2000-10
The solar thermal power generation system disclosed in Japanese Patent No. 11116 has a problem that the conversion efficiency is not sufficient because the performance of thermoelectric conversion materials that are currently known is low. In order to increase the power generation efficiency in this system, it is necessary to make a large temperature difference between the heat medium and the refrigerant.
For example, a special material such as metallic sodium is required, and there are many problems in terms of safety. Furthermore, the Peltier cooling device is driven by using part of the power generated by the solar cell panel, and the solar cell panel is cooled by the heat pipe, so part of the power generated by the solar cell panel is consumed. There is.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in claim 1, the solar cell has the same shape as the solar cell on the back side of the light receiving surface. In the solar power generation module, a cooling unit having a circulation hole is provided inside, and a flowing cooling medium is passed through the circulation hole of the cooling unit to cool the photovoltaic power generation cell. Thereby, the temperature rise of the photovoltaic power generation cell is suppressed to prevent the power generation efficiency from decreasing.

According to a second aspect of the present invention, in order to increase the amount of received light per unit area of the photovoltaic power generation cell, a light concentrating device equipped with a solar light tracking device is provided. A fixed frame that is provided so as to be inclined by a support column that can extend and contract facing the photovoltaic cell, a reflector that is rotatably provided on the fixed frame, and a reflector drive device that drives the reflector. It is configured. Further, in claim 3, the reflecting surface of the reflector of the light collecting device is formed by a plane mirror or a concave mirror. With such a configuration, the amount of sunlight collected is increased to improve the power generation efficiency.

In claim 4, liquids such as tap water and hydrocarbon oil, air and gases such as nitrogen gas used in the facility are generally easily available and easy to handle, and there is no danger. Liquid or gas is used as a fluid cooling medium.

According to the present invention, the photovoltaic cells are cooled and heat is recovered from the fluid cooling medium that has become high temperature, and is used as a heat source for hot water, heating or the like.

According to a sixth aspect of the present invention, a thermoelectric conversion element is sandwiched between the solar power generation cell and the cooling unit, and power is generated by utilizing a temperature difference between the solar power generation cell and the cooling unit. Recovers the discarded solar energy as electricity,
The power generation efficiency of the entire power generator is improved.

In the present invention, a liquid having a boiling point lower than the control temperature of the photovoltaic cell, such as ammonia or methanol, is used as the fluidized cooling medium, and the evaporative gas is generated in the cooling section, and the evaporative gas is used. Power is generated by rotating the turbine of the generator. As a result, not only the heat capacity of the liquid but also the latent heat of vaporization can be used for cooling, so that the cooling efficiency is increased, and the solar energy that has been discarded as heat is recovered as electricity to improve the power generation efficiency of the entire power generation device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments and can be implemented with appropriate modifications. FIG. 1 is a schematic view of a photovoltaic power generation module of a power generation device using solar energy showing an example of an embodiment according to claim 1 of the present invention, and FIGS. 2 and 3 are sunlight showing an example of another embodiment. It is a schematic diagram of a power generation module. In FIG. 1, a photovoltaic power generation module 1 includes a cooling unit 3 having substantially the same shape as the photovoltaic power generation cell 2 on the back side of a light receiving surface of a photovoltaic power generation cell 2 having a desired thickness and formed in a substantially quadrilateral shape. Are in contact with each other. Inside the cooling unit 3, a plurality of circulation holes 6 having a circular cross section are provided side by side so as to penetrate the opposite end portions so that the surface area of the photovoltaic cell 2 is cooled substantially uniformly.

The low-temperature fluid cooling medium 4 injected from one end of the flow hole 6 is used for cooling the photovoltaic cell 2 to absorb heat, and is discharged from the other end as a high-temperature fluid cooling medium 5. In this way, by injecting the low-temperature fluid cooling medium 4 from one end, it is possible to prevent the photovoltaic power generation cell 2 from reaching a high temperature, so that it is possible to prevent a decrease in power generation efficiency. In addition, the solar power generation module 1 may be installed individually or in a plurality of vertically and horizontally connected panels. In addition, as shown in FIG. 2, in another embodiment, a plurality of quadrangular cross-sections that penetrate the inside of the cooling unit 3a so as to penetrate the opposite ends so that the surface area of the photovoltaic cell 2 is cooled substantially uniformly. The circulation holes 7 are arranged side by side.
Further, as shown in FIG. 3, in still another embodiment, inside the cooling unit 3c, a jacket 8 is formed so as to penetrate the opposite ends so that the surface area of the photovoltaic cell 2 is uniformly cooled. Has been done.

FIG. 4 is a block diagram of a power generator using solar energy showing an example of an embodiment according to claim 2. In FIG. 4, the power generator using solar energy is composed of the movable light collector 11 and the power generator 30, and is installed in a place such as a building or various structures where sunlight can be collected.

The movable condensing device 11 includes a long column 12 and a short column 13 which can be expanded and contracted at appropriate positions such as buildings and various structures.
Is provided upright, and a fixed frame 14 is attached to the tip ends of the pin couplings of the two columns 12 and 13 in an inclined shape so as to face the photovoltaic cell 2. The fixed frame 14 includes a plurality of reflectors 1.
5 are rotatably supported at appropriate intervals. The reflector 15 includes a rotating shaft 16 rotatably attached to the fixed frame 14, and a support shaft 17 fixed to the rotating shaft 16.
It comprises a reflecting portion 18 attached to the tip of the support shaft 17. Since the rotating shaft 16 is connected to a gear mechanism 20 meshed with a reflector driving device 19 mounted on the fixed frame 14, the rotating shaft 16 drives the reflector driving device 19, for example, about 1 rotation speed of the earth. By rotating at / 2, the reflecting portion 18 follows the movement of the sunlight through the gear mechanism 20 so that the reflecting portion 18 tracks the sunlight at a more appropriate angle. The reflector driving device 19 is driven at night to return to the initial state in preparation for the next day's sunlight collection.

In the present embodiment, the movable condensing device 11 which can be tracked only in the horizontal direction is used. However, by manually or automatically expanding and contracting the extendable and retractable long column 12, tracking in the vertical direction or vertical and horizontal can be performed. Can be tracked in both directions. Furthermore, by matching the rotation axis 16 with the earth axis (the rotation axis of the earth), it is not necessary to perform vertical angle adjustment every day, and for example, weekly, seasonal, monthly, or seasonal sunlight can be generated once. It can be a movable light-collecting device for tracking.

In addition, as another embodiment, the plurality of reflectors 15 are provided at positions facing each other on the outer peripheral surface of the rotating shaft 16.
It can be installed so that the reflection surface of sunlight faces the outer peripheral side. With this structure, it is sufficient to rotate the rotating shaft 16 by 180 degrees to collect sunlight per day, and the rotating shaft 16 may be continuously rotated by 180 degrees the next day. This drives the reflector driving device 19 at night,
It becomes unnecessary to reversely rotate the rotary shaft 16 to return it to the initial state.

The power generator 30 is a solar power generation module 1
(A solar cell having a cooling unit on the back surface), a power receiving device 31 for storing electricity generated by the solar cell 2, and a circulation device for circulating a flowing cooling medium in the cooling unit 3. ing. The sunlight 10 is reflected by the reflecting portion 18 provided in the movable light concentrating device 11, is condensed as the reflected light 9 in the solar power generation cell 2, and is generated. The generated electricity is sent to the power receiving device 31 via the power feeding line 32.
Although not shown, a DC / AC conversion inverter is connected to the power transmission side of the power receiving device 31.

The circulation device comprises a circulation pump 33 for circulating the fluid cooling medium in the cooling section 3 and a storage tank 34 for storing the fluid cooling medium. The solar power generation cell 2 is warmed by the sunlight 10 to reach a high temperature and the power generation efficiency decreases. Therefore, the fluid cooling medium is stored in the storage tank 34, and the circulation pump 3 is provided between the storage tank 34 and the cooling unit 3.
3 through the pipe 35, the fluid cooling medium is circulated through the plurality of circulation holes 6 and 7 or the jacket 8 of the cooling unit 3 which is in contact with the back side of the light receiving surface of the solar power generation cell 2, and the solar The photovoltaic cell 2 is being cooled. Although the fluid cooling medium is circulated by the circulation pump 33 in the present embodiment, the storage tank 34 may be installed at a position higher than the photovoltaic power generation cell 2 and allowed to flow naturally. Further, the reflector 15 does not need to be installed on the one set of the movable light concentrator 11, and the reflector 15 is separately installed at a plurality of places so that one set of the photovoltaic cells 2 can collect light. Good.

In claim 3, the movable condensing device 1
The reflector 18 of the first reflector 15 is formed of a plane mirror or a concave mirror. Since the reflection part 18 needs to reflect the sunlight 10 and focus it on the photovoltaic cell 2, the reflection part 18 has silver or tin amalgam or the like on the back surface of the glass or plastic formed on the flat surface or the concave surface. A plane mirror or a concave mirror is formed by a known manufacturing method applied. Instead of the mirror made of glass or plastic, the surface of the metal may be polished to form a flat mirror or a concave mirror.

In claim 4, a liquid or a gas is used as the fluid cooling medium. As the liquid, tap water, fuel oil such as hydrocarbon oil, ammonia, methanol or the like is used. As the gas, air or nitrogen gas used in the facility is used. These are generally readily available, easy to handle, and non-hazardous.

FIG. 5 is a main part configuration diagram of a power generator 30a showing an example of an embodiment according to claim 5. As shown in FIG. A feature of this embodiment is that heat is recovered from the fluidized cooling medium that has reached a high temperature. In FIG. 5, tap water is stored in the storage tank 34a as a fluid cooling medium.
A water level controller 36 and a solenoid valve 37 that operates by receiving a signal from the water level controller 36 are provided at a. The solenoid valve 37 is controlled so as to be opened when the water level of the storage tank 34a becomes lower than the set water level, inject tap water into the storage tank 34a, and closed when the set water level is reached to stop the inflow of tap water.

The tap water in the storage tank 34a is injected into the cooling section 3a for cooling the photovoltaic power generation cell 2a by the circulation pump 33a to cool the photovoltaic power generation cell 2a. The tap water used for cooling absorbs heat and becomes hot water. Storage tank 3
Reflux to 4a. When the hot tap water is used as hot water or a heat source for heating, it can be taken out from the bypass pipe 38. In this case, the water level controller 36 detects a drop in the water level of the storage tank 34a, the electromagnetic valve 37 is opened, and low temperature tap water is injected into the storage tank 34a.
As another embodiment, tap water used for cooling may be directly injected into the cooling unit 3a without passing through the storage tank 34a.

FIG. 6 is a block diagram of the main part of a power generator 30b showing an example of an embodiment according to claim 6. In FIG. A feature of this embodiment is that the thermoelectric conversion element 40 is used to improve the power generation efficiency by using both solar power generation and solar heat power generation. In FIG. 6, the thermoelectric conversion element 40 is sandwiched between the photovoltaic power generation cell 2b and the cooling unit 3b. The thermoelectric element 40 is formed by joining a P-type semiconductor and an n-type semiconductor to form an annular circuit, and a current flows when one of the joints has a high temperature and the other has a low temperature. The feature is that it is a plate shape. As shown in FIG. 6, since one side of the thermoelectric conversion element 40 is in contact with the photovoltaic power generation cell 2b, the temperature of the photovoltaic power generation cell 2b rises and the temperature becomes higher. In addition, the thermoelectric conversion element 40
The other side is in contact with the cooling part 3b, so that it is on the low temperature side.

As a result, a temperature difference is generated on both sides of the thermoelectric conversion element 40, and when the solar thermal energy of the photovoltaic power generation cell 2b is transmitted to the fluid cooling medium, it is directly converted into electric energy to generate electricity. The generated electricity is sent to the power receiving device 30b via the power feeding line 32b. In this embodiment, since the photovoltaic power generation by the photovoltaic power generation cell 2b and the solar thermal power generation by the thermoelectric conversion element 40 are used together, it is possible to further improve the power generation efficiency as compared with the case where only the photovoltaic power generation cell 2b generates power. You can

FIG. 7 is a block diagram of a main part of a power generator 30c showing an example of an embodiment according to claim 7. As shown in FIG. The feature of this embodiment is that it incorporates a power generation device 30c that generates electric power by using the evaporative gas 41 generated from the fluid cooling medium.
As shown in FIG. 7, the generator-equipped turbine 42 and the condenser 43 are provided between the storage tank 34c and the cooling unit 3c. In the present embodiment, as the fluid cooling medium, for example, ammonia (boiling point −33.35 ° C.) or methanol (boiling point 6
4.65 ° C.) such as a liquid having a boiling point not higher than the control temperature of the photovoltaic cell 2c is used. Liquid ammonia or methanol used as a fluid cooling medium is cooled by the cooling unit 3
When passing through c, it absorbs heat and becomes evaporative gas 41. The evaporative gas 41 rotates the turbine 42 with a generator to generate electricity, and the generated electricity is supplied to the power receiving device 31 via the power feeding line 32c.
sent to c. Ammonia and methanol used as the evaporative gas 41 are liquefied by the condenser 43 and stored in the storage tank 34c.
Will be collected. In the present embodiment, not only the heat capacity of ammonia or methanol, which is a fluid cooling medium, but also latent heat of vaporization can be used for cooling, so that the cooling efficiency is increased and the solar thermal energy discarded as heat can be recovered as electricity. The power generation efficiency can be improved.

[0027]

According to the first aspect of the present invention, a cooling unit having substantially the same shape as the photovoltaic cell and having a through hole therein is provided on the back side of the light receiving surface of the photovoltaic cell, and the cooling unit is provided in the cooling unit. The photovoltaic cell is cooled by passing a fluid cooling medium. As a result, it is possible to prevent a temperature rise of the photovoltaic power generation cell, and thus it is possible to improve power generation efficiency.

According to a second aspect of the present invention, there is provided a light concentrating device having a sunlight tracking mechanism for concentrating sunlight on the light receiving surface of the solar power generation cell, wherein the light concentrating device is the sun. Consists of a fixed frame that is tiltably provided by a pillar that can expand and contract with respect to the photovoltaic cell, a reflector that is rotatably provided on the fixed frame, and a reflector drive device that drives the reflector. Has been done. Further, in claim 3, the reflecting surface of the reflector of the light collecting device is formed by a plane mirror or a concave mirror.
Due to this, the sunlight can be efficiently collected on the photovoltaic power generation cell, so that the power generation efficiency can be improved.

In the fourth aspect of the present invention, a liquid such as tap water or hydrocarbon oil or a gas such as air or nitrogen gas is used as the fluid cooling medium. These are generally useful as fluidized cooling media because they are readily available, easy to handle, and non-hazardous.

In the fifth aspect of the present invention, heat is recovered from the fluidized cooling medium that has become high temperature by cooling the photovoltaic cells. As a result, the waste heat that was conventionally discarded can be used as a heat source for hot water, heating, and the like.

According to a sixth aspect of the present invention, a thermoelectric conversion element is sandwiched between the photovoltaic cell and the cooling section, and power is generated by utilizing the temperature difference between the photovoltaic cell and the cooling section. There is. As a result, the solar thermal energy that has been discarded as heat can be recovered as electricity, so that the power generation efficiency of the entire device can be improved.

In the seventh aspect of the present invention, the fluidized cooling medium is vaporized and gasified in the cooling section, and the turbine is driven by using the vaporized gas to generate electric power. As a result, not only the heat capacity of the liquid but also the latent heat of vaporization can be used for cooling, so that the cooling efficiency is increased and the solar thermal energy that has been discarded as heat can be recovered as electricity, so the power generation efficiency of the entire device can be improved. .

[Brief description of drawings]

FIG. 1 is a schematic view of a solar power generation module of a power generation device using solar energy showing an example of an embodiment according to claim 1 of the present invention.

FIG. 2 is a schematic view of a solar power generation module of a power generation device using solar energy showing an example of another embodiment according to claim 1 of the present invention.

FIG. 3 is a schematic view of a solar power generation module of a power generation device using solar energy showing an example of another embodiment according to claim 1 of the present invention.

FIG. 4 is a configuration diagram of a power generation device using solar energy showing an example of an embodiment according to claim 2 of the present invention.

FIG. 5 is a main part configuration diagram of a power generation device using solar energy showing an example of an embodiment according to claim 5 of the present invention.

FIG. 6 is a main part configuration diagram of a power generation device using solar energy showing an example of an embodiment according to claim 6 of the present invention.

FIG. 7 is a main part configuration diagram of a power generation device using solar energy showing an example of an embodiment according to claim 7 of the present invention.

[Explanation of symbols]

1, 1a, 1b, 1c Solar power generation module 2, 2a, 2b, 2c Photovoltaic cell 3, 3a, 3b, 3c Cooling unit 4 Low temperature fluid cooling medium 5 High temperature fluid cooling medium 6 Circular cross-section hole 7 Circular cross-section through hole 8 jacket 9 reflected light 10 sunlight 11 Movable light collector 14 fixed frame 15 reflector 18 Reflector 19 Reflector drive 20 gear mechanism 30, 30a, 30b, 30c Power generator 31 Power receiving device 33, 33a, 33b, 33c Circulation pump 34, 34a, 34b, 34c Storage tank 36 Water level controller 37 Solenoid valve 40 thermoelectric conversion element 41 Evaporated gas 42 Turbine with generator 43 condenser

Claims (7)

[Claims] 1. A cooling unit having substantially the same shape as the photovoltaic cell and having a circulation hole inside is provided on the back side of the light receiving surface of the photovoltaic cell, and a fluid cooling medium is passed through the circulation hole of the cooling unit. A photovoltaic power generation module that cools the photovoltaic power generation cell according to claim 1 is used. 2. A light concentrating device comprising a sunlight tracking mechanism for concentrating sunlight on the light receiving surface of the photovoltaic power generation cell, wherein the light concentrating device faces the photovoltaic power generation cell. It is composed of a fixed frame tiltably provided by an extendable column, a reflector rotatably provided on the fixed frame, and a reflector driving device for driving the reflector. A power generator using solar energy according to claim 1. 3. The reflecting surface of the reflector of the light collecting device is formed by a plane mirror or a concave mirror.
A power generator using the described solar energy. 4. The power generator using solar energy according to claim 1, wherein the fluid cooling medium is liquid or gas. 5. The power generator using solar energy according to claim 1, wherein heat is recovered from the fluidized cooling medium that has become high temperature by cooling the photovoltaic power generation cell. . 6. The thermoelectric conversion element is interposed between the photovoltaic power generation cell and the cooling unit, and power is generated by utilizing a temperature difference between the photovoltaic power generation cell and the cooling unit. A power generator using the solar energy according to any one of 4 to 4. 7. The fluidized cooling medium is gasified in the cooling section,
The power generation device using solar energy according to any one of claims 1 to 4, wherein power is generated by driving a turbine using the gasified gas body.