JPH0511602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solar light concentrating device, and more particularly to a solar light concentrating device that condenses sunlight using multiple reflectors.

[Conventional technology]

When generating electricity using solar cells, it is necessary to concentrate sunlight to reduce the amount of solar cells used, or when directing sunlight from outdoors and using it indoors, the diameter of the id of the light can be reduced, etc. equipment is used.

Conventionally, as this type of sunlight condensing device, one using a convex lens or one using a concave mirror has been widely used. However, since these focus sunlight on the focal point of a convex lens or concave mirror, the directivity is narrow and accurate sunlight tracking is required, and the curvature accuracy and surface accuracy of the convex lens or concave mirror are strictly required. The disadvantage is that it is expensive.

In order to solve these drawbacks, a plurality of reflectors having outwardly convex aperture cross sections with different curvatures are combined, with the one with the larger curvature facing outward, and the ones with smaller curvatures are sequentially combined on approximately the same axis. 2. Description of the Related Art A multi-reflection type solar light condensing device in which reflective surfaces are provided on mutually opposing portions is known. FIG. 2 is a sectional view of one example.

The conventional example shown in FIG. 2 includes reflecting plates 11 to 14 whose curvatures are successively reduced. A small hole is provided in the center of each of the reflecting plates 11 to 14.
The reflecting plates 11 to 14 are arranged so that their central axes 5 coincide with each other and their small holes are close to each other. The opposing surfaces of the reflecting plates 11 to 14 are reflective surfaces.

The sunlight incident from the direction of the optical path 7 is reflected by the reflector 1
1 and 12, the light is repeatedly reflected and condensed onto the condensing surface 6.

The shape of the reflecting plates 11 to 14 may be hemispherical or polygonal pyramidal. The number of reflecting plates is also not limited to four.

A solar light concentrator with a structure as shown in Fig. 2 is economical because it does not require sunlight tracking or its accuracy may be poor, and the curvature accuracy and surface accuracy of the reflecting surface may be rough. It has the advantage that it is easy to increase the light collection ratio by several tens of times.

[Problem that the invention seeks to solve]

As explained above, conventional solar concentrators are
Convex lenses and concave mirrors have the disadvantage of being expensive, while multi-reflector types require a large amount of storage space when not in use, and are heavy because each reflector has rigidity to maintain its shape. It has the disadvantage of being large.

The object of the present invention is to solve the above-mentioned drawbacks, and to provide a small storage space when not in use, lightweight,
Moreover, it is an object of the present invention to provide an inexpensive solar light condensing device.

[Means for solving problems]

The solar light condensing device of the present invention has an opening toward one direction of the central axis, and a curved surface whose cross section including the central axis is convex to the outside receives sunlight, except for a small part at the center. The portion other than the curved surface portion and the small portion are flexible membranes that have a high reflectance to sunlight and have a plurality of balloon-shaped bags of different sizes. , the small bags are sequentially arranged inside the large bag so that the central axes coincide with each other and the small parts are close to each other.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments.

FIG. 1a is a sectional view of an embodiment of the solar light concentrating device of the present invention, and FIGS. 1b and 1c are enlarged views of portions A and B in FIG. 1a.

The embodiment shown in FIG. 1a has transparent parts 1a, 2a,
3a, 4a and reflective parts 1b, 2b, 3b, 4b
The balloon includes balloons 1, 2, 3, and 4 of different sizes and transparent parts 1c, 2c, 3c, and 4c.

The reflecting portions 1b to 4b are located at the first center of their central axis 5.
It opens upward in the figure and has a curved cross-sectional shape that is convex to the outside. Reflector 1b
Transparent parts 1c to 4c are provided in the center of 4b. Balloons 2-4 inside balloons 1-3
However, the central axes 5 of the reflective parts 1b to 4b coincide with each other, and the transparent parts 1c to 4c are arranged so as to be close to each other.

The transparent parts 1a to 4a are made of a Teflon sheet 101, as illustrated in FIG. 1b, and have high transmittance to sunlight and are flexible. As illustrated in FIG. 1c, the reflective parts 1b to 4b include a sheet that is integral with the sheet 101 of the transparent parts 1a to 4a, a Teflon sheet 103 that overlaps with the sheet 101, and sheets 101 and 103. It is made of sandwiched aluminum foil 102 and is flexible. Both the outer and inner surfaces of the reflective parts 1b to 4b have high reflectance to sunlight. The transparent parts 1c to 4c are
It is made of a sheet integrated with the sheet 101 of the transparent parts 1a to 4a and the reflective parts 1b to 4b, and has high transmittance to sunlight.

When the embodiment shown in FIG. 1a is used, gas is filled in the balloons 1 to 4, and the shape of the reflecting portions 1b to 4b is kept regular by the pressure thereof. As a result, the shape of the reflecting portions 1b to 4b becomes the same as the shape of the reflecting plates 11 to 14 of the conventional example shown in FIG. 2, and in this case, the embodiment shown in FIG. In the conventional example shown in FIG. 2, sunlight incident from above is condensed onto the condensing surface 6.

When not in use, the balloons 1-4 can be folded into a small size by removing the gas inside.

The sheets 101 and 103 are not limited to being made of Teflon, but may be any material as long as they have a high transmittance to sunlight and are flexible. There are many polymeric materials other than Teflon that can be used to obtain such sheets. If the sheets 101 and 103 are made of a polymer compound, heat dissipation can be improved since polymer compounds generally have a high infrared emissivity. Silver foil or the like can be used instead of the aluminum foil 102, and the reflective parts 1b to 4b can also be made by vapor depositing aluminum, silver, or the like on the sheet 102.

Although the present invention has been described above with reference to examples, the balloon is not limited to four layers.
Further, the shape of the reflecting portion can also take various shapes such as a hemisphere and a polygonal pyramid.

〔Effect of the invention〕

As explained in detail above, the solar light concentrating device of the present invention has a multiple reflector type structure in which a part of the multiple balloon reflects sunlight and the other part is transparent. It is economical because optical tracking is not required or its accuracy may be poor, and the curvature accuracy and surface accuracy of the multiplex balloons can be rough. The shape of the reflecting part can be maintained correctly due to the pressure of the gas.
Even if the maximum diameter of the multiplex balloon is increased to increase the light condensing ratio, it is still lightweight, in other words, the light condensing ratio per unit weight is large.Also, the multiplex balloon is flexible, and the gas inside Since it can be folded into a small size without using it, it has the effect of requiring a small storage space when not in use. If the present invention is applied to a solar light concentrator used in a space vehicle, and the multiple balloons are folded into a small size at the time of launch and deployed in outer space, the volume occupied by the payload storage area of a rocket etc. will be small. The combination of this and its light weight has an extremely large economic effect of reducing launch costs.

[Brief explanation of drawings]

Figure 1a is a sectional view of an embodiment of the solar light concentrating device of the present invention, Figures 1b and 1c are enlarged views of portions A and B in Figure 1a, and Figure 2 is a conventional solar light concentrating device. FIG. 2 is a cross-sectional view of an example of a solar light concentrator. 1 to 4...Balloon, 1a to 4a...Transparent part,
1b to 4b...reflective part, 1c to 4c...transparent part.

Claims (1)

[Scope of Claims] 1. A curved surface that is open toward one direction of the central axis and whose cross section including the central axis is convex to the outside has a low reflectance to sunlight except for a small portion at the center. The part excluding the curved part and the small part are made of a flexible film having high transmittance to sunlight, and are provided with a plurality of balloon-shaped bags of different sizes, and the center A solar light condensing device characterized in that the smaller bags are sequentially arranged inside the larger bag so that their axes coincide with each other and the small parts are close to each other. 2. The solar light condensing device according to claim 1, wherein the film is made of a polymer compound in which a portion with a high reflectance to sunlight is formed by metal vapor deposition. 3 The film consists of a polymer compound film and a thin metal film,
2. The solar light condensing device according to claim 1, wherein a portion having a high reflectance to sunlight is formed by the metal thin film supported by the polymer compound film.