JPH0340293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar energy converter that converts sunlight into heat and electricity, and more particularly to a solar energy converter that can efficiently convert sunlight into heat and electricity.

Conventionally, a solar energy converter has been proposed in which a solar cell as an electrical converter is attached to a heat collection plate of a solar heat collector, which is a type of thermal energy converter. However, in these solar energy converters, the solar cells are mounted on a heat collecting plate, and when irradiated with sunlight, the solar cells themselves become hot. The output characteristics of a solar cell generally decrease as the temperature increases, as shown in the example of FIG. Therefore, conventional solar energy converters have the disadvantage that the conversion efficiency of the solar cells decreases as the temperature rises, regardless of the area of the solar cells.

Furthermore, in the conventional solar energy converter described above, the solar cells are usually attached to the entire light-receiving surface of the heat collecting plate, so a large-area solar cell is required. Large-area solar cells are disadvantageous in that they are expensive and difficult to manufacture.
It has the disadvantage that the conversion efficiency per unit area is lower than that of small-area solar cells.

In addition, as shown in Figure 2 as an example of the sensitivity spectrum B of an amorphous silicon solar cell, the wavelength that solar cells can efficiently convert into electrical energy is limited to a narrow range, so the sunlight spectrum A
There was also a problem in that the spectrum outside this wavelength range was not effectively utilized in the past.

This invention was made to solve these various problems, and has superior energy conversion efficiency compared to conventional solar thermal energy converters, and in particular, the electrical energy conversion efficiency of solar cells is significantly superior. A solar energy converter is provided.

Thus, according to the present invention, there is provided a solar energy converter comprising a heat medium pipe, a heat medium introduction pipe that sends a heat medium to the heat medium pipe, a heat collecting plate thermally connected to the heat medium pipe, and a solar cell. And on the light receiving surface of the heat collecting plate,
A light-transmitting layer containing a phosphor having a fluorescence maximum wavelength within the effective sensitivity spectrum of the solar cell is deposited, a solar cell is provided on the side surface of this light-transmitting layer, and the light-receiving surface of this solar cell is on the light-transmitting layer. A solar energy converter is provided, characterized in that the solar energy converter is disposed toward the solar energy.

In this invention, a heat medium introduction tube is connected in a thermally conductive state to the outer surface of the solar cell provided on the side surface of the light-transmitting layer, and this is further connected in series to the heat medium tube bonded to the heat collecting plate. If the heat medium is configured to flow from the outer surface of the solar cell toward the heat collecting plate by adding a passage, the solar cell can be cooled and kept at a low temperature, and as mentioned above, the energy conversion efficiency will further increase. Moreover, it is preferable because the amount of heat held by the solar cell can also be collected, and the effects of the present invention can be more effectively exerted.

On the other hand, it is also possible to apply a configuration in which the heat medium pipe and the heat collecting plate are surrounded and sealed by a transparent outer tube, and in this case, the solar energy converter according to the present invention can be protected from the external environment such as rain and wind. Preferably,
Furthermore, it is preferable to vacuum insulate the inside of the light-transmitting outer tube because heat loss due to convection of the heat collecting plate can be reduced and the effects of the present invention can be more effectively achieved.

In this invention, the solar cell may be provided on at least one side of the light-transmitting layer, and in some cases may be provided on the entire side surface, and at least its light-receiving surface is in close contact with the light-transmitting layer. It is sufficient if it is set up like this.

The present invention will be explained in detail below with reference to additional drawings.

FIG. 4 is a plan view of the main part showing a specific example of the solar energy converter of the invention, and FIG.
It is a sectional view taken along line EE' in the figure. In the figure, heat medium pipe 1 consists of a copper pipe through which a heat medium such as water flows.
are bonded in a thermally conductive state parallel to the longitudinal direction on the lower surface of the elongated heat collecting plate 2 made of copper or aluminum via a bonding layer 7 made of an epoxy adhesive. The light-receiving surface (upper surface) of the heat collecting plate 2 is coated with the phosphor Hostasol, which is the light-transmitting layer of the present invention.
A long translucent substrate 3 (thickness approximately 1 to 50 mm) made of glass or acrylic resin containing Orange (a mixture of Solvent Yellow No. 98 and Solvent Orange No. 63 in the phosphor color index).
degree) is coated. Strip-shaped amorphous silicon solar cells 5 are provided on both sides of the transparent substrate 3, respectively.
are arranged closely to the substrate 3 so that their light-receiving surfaces face each other. Heat medium introduction tubes 6 connected in series to the heat medium tubes 1 are bonded to the outer surfaces of the solar cells 5 through bonding layers 7' made of epoxy adhesive in a thermally conductive state. . Note that 4 is a selectively transmitting film that selectively transmits only the wavelength range effective for energy conversion of sunlight (usually visible and some ultraviolet regions), and the present invention can be achieved even without providing this selectively transmitting film. There are no hindrances to its implementation.

The effects of the solar energy converter having the above configuration will be described below.

First, sunlight is irradiated from the direction of the arrow in the figure, passes through the selective transmission film 4, and enters the transparent substrate 3. A portion of the incident light is absorbed by the phosphor inside the translucent substrate 3.
Excite Hostasol Orange to make it fluoresce. FIG. 3 shows the wavelength characteristics of the phosphor used in this specific example. In FIG. 3, C indicates the absorption spectrum region of the phosphor, and D indicates the fluorescence spectral region of the phosphor. That is, as is clear from FIGS. 2 and 3, in the sunlight spectrum A, amorphous silicon solar cells have low sensitivity at wavelengths of about 0.35 to about
A wavelength of approximately 0.55 to approximately 0.6 μm where 0.5 μm light is absorbed by the phosphor and amorphous silicon solar cells exhibit excellent sensitivity.
is converted into light. Fluorescence emitted from the phosphor spreads isotropically within the translucent substrate, but due to the effect of total internal reflection, it undergoes multiple reflections and is mostly focused on both sides of the translucent substrate, each facing the light-receiving surface of the amorphous silicon solar cell. incident on . Since this incident light almost coincides with the peak of the effective sensitivity range (approximately 0.55 to 0.6 μm) of the sensitivity spectrum B of the solar cell, it is converted into electrical energy with high efficiency. That is, since light can be effectively focused by a light-transmitting substrate containing a phosphor that converts the wavelength of light, a small-area solar cell can convert light energy equivalent to a large-area solar cell. Of course, sunlight itself has about 0.55 ~
Light with a diameter of 0.6 μm also undergoes multiple reflections and is efficiently focused on the solar cells. Furthermore, since the solar cell itself is not directly irradiated with sunlight, the temperature rise is smaller than in the past, and the conversion efficiency of the solar cell itself is maintained at a good level, making it possible to maintain excellent light energy conversion efficiency.

On the other hand, downward light, which is mainly composed of wavelengths that are not absorbed by the phosphor, passes through the transparent substrate 3 and passes through the heat collecting plate 3.
is absorbed and used as heat energy. In this case, the transparent substrate 3 also functions as a heat radiation prevention material for the heat collecting plate, and has the effect of increasing the thermal energy conversion efficiency.

In addition, a heat medium such as low-temperature water passes through heat medium introduction pipes 6 to cool the solar cells 5, and is then introduced into heat medium pipe 1, heated by heat collecting plate 2, and heated to a high temperature outside. (In Figure 4,
(see arrow). Therefore, the solar cell is constantly cooled and kept at a low temperature together with the effect provided on the side, so that far superior electrical energy conversion efficiency can be obtained compared to the conventional method.

In addition to the amorphous silicon solar cells described above, solar cells used in this invention include single crystal silicon solar cells, Ga-As solar cells, Ge solar cells,
Various solar cells used in the field, such as Cd--Te solar cells, can be applied. In addition,
The phosphor used in this case may be one that has a fluorescence wavelength peak within the effective sensitivity range of the sensitivity spectrum of the applied solar cell, such as the combination of the amorphous silicon solar cell and Hostasol Orange. It is preferable to have a fluorescence wavelength peak near the effective sensitivity peak of . Phosphors with such fluorescence wavelength peaks are, for example, Solvent Yellow No. 98 and Solvent Yellow in the phosphor color index.
Obtained by mixing No. 126 and Solvent Orange No. 63 at an appropriate mixing ratio, the fluorescence wavelength can be changed by changing the mixing ratio, and it can be applied to various solar cells. . Note that various other organic phosphors can also be used.

In addition, as mentioned above, if the solar energy converter described in the specific example is installed inside a translucent outer tube made of glass or the like, and the inside is vacuum insulated, as the cross section is shown in Figure 6, thermal energy can be more effectively converted. It is more preferable because it can be taken out. In addition, in Figure 6, 8
9 indicates a translucent outer tube, and 9 indicates an appropriate number of stays provided for fixing.

The solar energy converter according to the present invention can keep solar cells at a lower temperature than conventional ones, and matches the sensitivity characteristics of solar cells by using a transparent layer containing phosphor to transmit light in a wavelength range that is conventionally unavailable. Because it can convert light into a specific wavelength and effectively focus it, even a small-sized solar cell can convert solar energy into electrical energy with high efficiency, reducing costs, and can also efficiently convert and utilize thermal energy. It has advantages.

[Brief explanation of drawings]

FIG. 1 is a graph showing an example of the output characteristics of an amorphous silicon solar cell. FIG. 2 is a graph showing the radiation spectrum of sunlight and the sensitivity spectrum of an amorphous silicon solar cell. FIG. 3 is a graph showing the absorption spectrum and fluorescence spectrum of the phosphor used in the specific example of this invention. FIG. 4 is a plan view of essential parts of a specific example of the solar energy converter of the present invention, and FIG. 5 is a sectional view taken along the line EE' in FIG. FIG. 6 is a sectional view corresponding to FIG. 5 showing another specific example of the solar energy converter of the present invention. DESCRIPTION OF SYMBOLS 1... Heat medium tube, 2... Heat collection plate, 3... Transparent substrate, 4... Selective transmission film, 5... Amorphous silicon solar cell, 6... Heat medium introduction tube, 7,7 ′... bonding layer,
8...translucent outer tube, 9...stay.

Claims (1)

[Scope of Claims] 1. A solar energy converter consisting of a heat medium pipe, a heat medium introduction pipe that sends a heat medium to the heat medium pipe, a heat collecting plate thermally connected to the heat medium pipe, and a solar cell. A light-transmitting layer containing a phosphor having a maximum fluorescence wavelength within the effective sensitivity spectrum of the solar cell is deposited on the light-receiving surface of the heat collecting plate, and a solar cell is provided on the side surface of this light-transmitting layer. A solar energy converter characterized in that the light-receiving surface of this solar cell is disposed toward a light-transmitting layer. 2. The converter according to claim 1, wherein the heat medium introduction tube for feeding the heat medium to the heat medium tube is thermally connected to the outer surface of the solar cell. 3. Claim 1, in which the entire heat collecting plate to which heat transfer pipes are thermally connected is surrounded and sealed with a transparent outer tube.
or the converter according to item 2.