JP2002286916A - Self-cleanable beam-condensing reflector and solar light collecting power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a beam-condensing reflector which is capable of preventing the degradation in the reflection luminance of the reflector by the random reflection by dew condensation and water drops and the deposition, etc., of contaminants by dust, etc., without carrying out maintenance over a long period. SOLUTION: A photocatalyst-containing layer is formed on the outside surface on the reflecting surface side of the reflector having beam condensability, as a result of which the photocatalyst of this layer is activated and is hydrophilized when irradiated with UV rays and short wavelengths visible rays. Even if not only the hydrophilic contaminants but the lipophilic contaminants adhere thereto, the water by rainfall, etc., intrudes between the hydrophilized surface and the contaminants to float the contaminants, thereby making the contaminants hardly adherable. Even if the contaminants adhere to the surface, the contaminants are easily flushed away by the rainfall, etc. The photocatalyst is activated by the irradiation with the UV rays and short wavelength visible rays to manifest strong oxidation power and therefor the deposited contaminants are easily decomposed and are more easily flushed away by the rainfall, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-collecting reflector having a self-cleaning function, and more particularly to a light-collecting reflector used in a solar light concentrating power generator.

[0002]

2. Description of the Related Art Hitherto, in order to enhance the efficiency of photovoltaic power generation, there have been proposed many methods of concentrating sunlight and supplying the light to a photovoltaic power generation panel. And those using a reflecting mirror and those using an optical fiber or an optical filter.

[0003] Among them, the method using a reflector allows a large area of sunlight to be converged by using a plurality of reflectors without having to make the size of the reflector alone so large. Because it is much lower cost than optical fiber, from the viewpoint of initial investment and power generation efficiency,
This is the most rational method.

[0004]

However, in this case, since the reflector is generally installed with the reflecting surface facing upward, dust and the like are apt to be contaminated by contamination, and the reflection brightness is lowered, so that the solar cell is deteriorated. Power generation efficiency also decreases. Further, in long-term use, pollutants that do not flow down only by natural washing with rainwater or the like accumulate, resulting in cloudy contamination and a remarkable reduction in reflection luminance. In addition, rainwater adheres and water droplets remain on the reflecting surface, which absorbs dust and the like in the air, and if dried as it is, a ring-shaped contaminant adheres to the part where the water droplet was present, which contributes to the decrease in reflection brightness Become.

[0005] Removal of such contaminants requires cleaning manually or with a cleaning device, but manual labor requires a great deal of labor and time, and increases labor costs. The method of providing the cleaning equipment requires initial capital investment. In addition, by performing cleaning with a brush, water jet, or the like, fine scratches are formed on the reflecting surface of the reflector, and these scratches also lead to a decrease in reflection luminance.

[0006] In a cold region or a cold period, dew condensation occurs on the surface of the reflector, and the amount of solar light to be reflected in the direction of the solar cell is irregularly reflected so that the amount of supplied light is significantly reduced, thereby lowering the efficiency of the solar cell. It becomes a factor. Water drops remaining on the reflecting surface after rainfall or the like also cause irregular reflection.

Therefore, the present invention solves the above-mentioned problems, and prevents a decrease in the reflection luminance of the reflector due to the condensation of water due to dew condensation or water droplets, the adhesion of contaminants due to dust or the like for a long time without maintenance. The present invention provides a light-collecting reflector that can be used.

[0008]

In order to achieve the above object, the present invention has the following arrangement. That is, the present invention is characterized in that a photocatalyst-containing layer is formed on an outer surface on the reflection surface side of a reflector having a light-collecting property.

According to the present invention, since the photocatalyst-containing layer is formed on the outer surface on the reflecting surface side of the reflector, the photocatalyst is activated by irradiating the photocatalyst with ultraviolet rays or short-wavelength visible rays, and its hydrophilicity is increased. Even if lipophilic contaminants adhere as well as hydrophilic contaminants, water due to rainfall etc. enters between the hydrophilized surface and the contaminants, and the contaminants are hardly adhered by floating the contaminants Even if it adheres, it is easily washed away by rainfall or the like. In addition, the photocatalyst is activated by irradiation of ultraviolet rays and short-wavelength visible light, and expresses a strong oxidizing power. Thus, the photocatalyst decomposes lipophilic substances that act as binders for attached contaminants, and contaminants such as rainfall. Makes it easier to wash away.

[0010] Further, even in a situation where the conditions for dew condensation are satisfied because the surface is hydrophilized, moisture adhering to the surface is uniformly diffused to the surface, so that even if dew is formed, light rays are irregularly reflected. As a result, the decrease in the amount of reflected light can be reduced. In addition, even after rainfall or the like, since water is uniformly diffused to the surface and water droplets are not generated, irregular reflection and adhesion of contaminants due to water droplets can be prevented.

The photocatalyst to be used is preferably titanium oxide, and may be of rutile type, but is preferably of anatase type or brookite type because of its high activity, and may be used alone or in combination. This titanium oxide is activated by irradiation with ultraviolet light or short-wavelength visible light, and the activation produces a strong oxidizing power. In addition, the surface is hydrophilized to a contact angle with water of about 0 to 20 degrees by the activation.

The photocatalyst-containing layer is preferably formed by binding fine photocatalyst particles with an inorganic binder, more preferably using silica. By using an inorganic binder, a layer having a uniform and thin film with little adverse effect on reflectivity can be formed, and the photocatalyst-containing layer has a
It can be made difficult to be decomposed by the oxidizing power of the photocatalyst itself. Furthermore, the hardness of the photocatalyst-containing layer can be improved, and the hard coat layer can also have the performance of protecting the substrate from scratches.

The reflector may have a reflecting surface formed of a plurality of flat surfaces or a single or a plurality of concave surfaces. When the reflecting surface is a plane, a plurality of reflectors are arranged with the reflecting surfaces facing the photovoltaic panel. When the reflecting surface is concave, the reflecting surfaces of a single or a plurality of reflectors are arranged facing the direction of the solar panel. If a single reflecting surface is a concave reflector, the efficiency of light collection can be increased, and if a plurality of reflectors are used, individual reflectors become smaller, and the cost of replacement in the event of damage or the like can be reduced, Further, since there is a gap between the reflectors, maintenance after installation can be facilitated.

The light-collecting reflector according to the present invention may be used as a light-reflecting member for condensing and supplying sunlight to a photovoltaic power generation panel. As described above, providing the self-cleaning property of the contaminants, anti-fog, and drip-proof properties contributes to maintaining the performance of the reflector reflecting the sunlight, and has a tremendous effect on preventing the efficiency of the solar power panel from decreasing. Demonstrate.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the light-collecting reflector of the present invention will be specifically described with reference to the drawings. That is, FIG. 1 shows an embodiment of the present invention, and FIG. 2 is a sectional view of the reflector in FIG.

The sunlight 10 emitted from the sun S falls on the earth and is reflected by the reflecting surface of the reflector 1 to become a reflected light 101. The reflected light 101 is formed because the reflector 1 has a concave shape. The light is collected and irradiated on the solar panel 2. Although the reflector has a concave shape, since it is not placed horizontally with the ground, water droplets adhering to the reflection surface due to rainfall, etc., naturally flow out of the concave portion of the reflector due to gravity, and contaminants are thus removed. Does not stay on top. In the present embodiment, the reflector is formed by one member, but may be formed by a plurality of members. In this case, each reflector may have a concave shape or a planar shape. It may be something. In addition, in the present embodiment, the gantry 3 supporting the reflector 1 has the reflection surface of the reflector fixed to the south surface in the present embodiment, but may be adjustable in angle and may be provided with a device for tracking the sun. Good.

In FIG. 2, the reflector 1 is made of a synthetic resin plate such as polycarbonate or acrylic, a stainless steel plate, glass, or the like in this embodiment, and has a reflective property.
1, a siliceous ceramic layer 12 is formed, and a photocatalyst containing layer 13 containing a photocatalyst such as titanium dioxide is formed on the outer surface. The siliceous ceramic layer 12 may be formed directly on the base material 11 or may be formed via another layer.

By irradiating the photocatalyst containing layer 13 with ultraviolet rays, the photocatalyst is activated and its surface is made hydrophilic, contaminants adhered to the surface are washed off by rainfall and the like, and the formation of dew and the formation of raindrops are reduced. It has been made to be prevented. It is preferable that the siliceous ceramic layer 12 and the photocatalyst-containing layer 13 be formed in a thickness that does not impair the reflection performance of the reflector.

FIG. 3 shows an embodiment of the present invention. The plurality of reflectors 1 each having a flat reflecting surface are supported by a supporting body 4 of the reflecting member, and are arranged such that the reflecting surfaces face the photovoltaic power generation panel 2 so as to collect light. Other parts are the same as those in the embodiment shown in FIG.

FIG. 4 shows an embodiment of the present invention. The plurality of reflectors 1 having a concave reflecting surface are supported by a reflector support 4, and are arranged such that the reflecting surfaces face the photovoltaic power generation panel 2 so as to collect light. Other parts are the same as those in the embodiment shown in FIG.

[0021]

According to the present invention, since the photocatalyst-containing layer is formed on the outer surface on the reflection surface side of the reflector, the photocatalyst is activated by irradiating the photocatalyst with ultraviolet rays or short-wavelength visible rays. Even if hydrophilic and hydrophilic contaminants as well as lipophilic contaminants adhere, water from rainfall enters between the hydrophilized surface and the contaminants, causing the contaminants to float. In addition, even if it adheres, it is easily washed away by rainfall or the like. In addition, the photocatalyst is activated by irradiation of ultraviolet rays and short-wavelength visible light, and expresses a strong oxidizing power. Thus, the photocatalyst decomposes lipophilic substances that act as binders for attached contaminants, and contaminants such as rainfall. Makes it easier to wash away.

Further, even when the conditions for dew condensation are satisfied because the surface is hydrophilized, moisture adhering to the surface is uniformly diffused to the surface, so that even when dew forms, light rays are irregularly reflected. As a result, the decrease in the amount of reflected light can be reduced. In addition, even after rainfall or the like, since water is uniformly diffused to the surface and water droplets are not generated, irregular reflection and adhesion of contaminants due to water droplets can be prevented.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 shows a cross section of a reflector surface portion in FIG.

FIG. 3 shows an embodiment of the present invention.

FIG. 4 shows an embodiment of the present invention.

[Description of Signs] S Solar 1 Reflector 11 Reflective base material 12 Silica ceramics layer 13 Photocatalyst containing layer 2 Photovoltaic panel 3 Mount 4 Reflector support 10 Sunlight 101 Reflected light

Continued on the front page F term (reference) 2H042 DA10 DA11 DA12 DA18 DB13 DC04 DC11 DD04 DD05 DE03 4G069 AA03 BA02A BA02B BA04A BA04B BA14A BA14B BA17 BA18 BA22A BA22B BA48A EA11 EB03 EC22X EC22Y ED01 ED04 JA03 BA03

Claims (6)

[Claims] 1. A self-cleaning light-collecting reflector having a light-collecting property, wherein a photocatalyst-containing layer is formed on an outer surface on a reflection surface side. 2. The self-cleaning condensing reflector according to claim 1, wherein the photocatalyst-containing layer is formed using titanium oxide, and the titanium oxide is an anatase type and / or a brookite type titanium dioxide. 3. The self-cleaning condensing reflector according to claim 1, wherein the photocatalyst-containing layer is formed by binding photocatalyst fine particles with an inorganic binder. 4. The self-cleaning condensing reflector according to claim 3, wherein the inorganic binder layer is formed using silica. 5. A reflector having a light-collecting property, wherein the reflection surface is formed of a plurality of planes, or is formed of a single or a plurality of concave surfaces.
The self-cleaning light-collecting reflector according to any one of the above items. 6. The solar light, wherein the self-cleaning condensing reflector according to claim 1 is used as a reflector for condensing and supplying sunlight to a solar power generation panel. Concentrating power generator.