JPS5917335B2 - solar radiation energy absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar radiant energy absorber capable of efficiently absorbing solar radiant energy.

A typical type of electromagnetic wave energy is solar radiation energy, and the average solar radiation intensity in Earth's orbit is approximately O, IW/cil (energy per million squared), and its spectral curve is As shown by curve I in Figure 1, the maximum value is near the wavelength of 0.5 μm, and the black body temperature (color temperature) is 5900'.

If solar radiant energy near 5900' can be converted into thermal energy with high efficiency, high-temperature heat can be obtained. Further, the characteristic when the black body temperature O (color temperature) is 700' is shown as a curve 2. The wavelength that gives the maximum energy intensity corresponding to 700° is about 4.5 μm, and the intensity at this wavelength is the maximum intensity of solar radiant energy (
5 μm), and most of the solar radiation energy is concentrated in the wavelength range of 0.3 to 2.0 μm.

Furthermore, in these two curves 1 and 2, the wavelength of the electromagnetic wave that gives the maximum radiant intensity differs depending on the black body temperature (color temperature), and the lower the black body temperature (color temperature), the longer the wavelength of the electromagnetic wave that gives the maximum radiant intensity. It shows that it becomes longer. In FIG. 1, the horizontal axis shows wavelength (μm) and the vertical axis shows relative intensity. By the way, solar radiant energy can be said to be inexhaustible, and if we can absorb this solar radiant energy efficiently, we can directly convert it into high-temperature heat and use it as a non-polluting, permanent thermal energy source. can.

When such solar radiant energy is absorbed by an absorber, the incident solar radiant energy may quickly escape depending on the surface condition of the absorber, making it impossible to efficiently absorb it.

Therefore, in order to increase the absorption efficiency, it is necessary to absorb the solar radiation energy once irradiated without missing it.
This invention was developed in consideration of the above points, and is designed to absorb most of the solar radiant energy once incident. The present invention will be explained below with reference to the drawings. First, the principle of this invention will be explained with reference to FIG.

Degree radiation (infrared radiation) is similarly reflected. At this time, L1-
No radiation loss occurs for the L2 portion. The vertical portion 4 forming the through hole of the introduction plate 1 may be used in cases where it is necessary due to the configuration of the microplate 1 (for example, when the partition wall 3 of the segment or the surface of the adjacent through hole 4 is filled with a transparent substance). ) is not necessary. In addition, in FIGS. 6 to 8, when solar radiation energy E is incident, the incident light that is incident outside point B, that is, at point A, is reflected by the mirror surface 5 as at point D, and the absorber 6 is not incident.

This relationship can be expressed as an equation, and the details will be described at the end of this book, but the function of this invention exists within the following conditions.

That is, d θ is 45°, ±≧0.5.

T,, l, In addition, the conditions for maximum U are: L The value of σ = ·Tanθ is close to 0.5.

According to experimental results, preferred values are in the following range.
That is, U1 −
Lq. - Tall θ=0.2 to 0.4, that is, -K 1.7 to TT5.

Therefore, considering Fig. 6, if the depth D of the slope with respect to the aperture length L becomes the effective depth D2, the incident light that enters point A will not become reflected light D, but will become an absorber. 6.

That is, all of the solar radiation energy E incident on the opening area S is incident on the absorber 6. In this way, the opening length L1
Since there is a certain relationship between , the depth D of the slope, and the slope angle θ, the efficiency can be improved by finding the optimal values for these using L plotting and designing so that `` is the maximum. Good concave glaze 2
can be formed.

Energy guide plate 1 configured based on this relationship
The entire surface, in other words, the surface other than the width 11 at the tip of the partition wall 3 where each concave portion 2 is adjacent, including the back surface, is coated with chrome or the like, metal vapor deposition technology, polishing, etc. Alternatively, the mirror surface 5 is formed by electroless plating or metal vapor deposition using a polymeric material.

Next, as shown in FIGS. 7 and 8, if the inclination angle θ (in this example, θ=20°, 30°) is increased, the number of reflections on the mirror surface 5 in the recess 2 will increase, and the reflection will be reflected in the through hole 4. By the time the light is focused, the loss increases and the absorption effect inevitably decreases.

Therefore, in order to increase the absorption efficiency, the number of reflections must be minimized. In other words, since the absorption efficiency η is a function of the tilt angle θ {η−f(θ)}, it is necessary to select the most efficient tilt angle θ. That is, as described above, the absorption efficiency is determined by the relationship between the aperture length L, the depth D of the sloped portion, and the slope angle θ. 9 and 10 show another embodiment of the present invention, which shows an energy introduction plate 11 having a tri-panel structure.

12 is a groove-shaped recess formed by a chevron-shaped partition wall 13;
A through hole 14 is formed in the bottom part, and a partition plate 15 is formed at a required interval.
A large number of independent recesses 12 are formed.

16 is a spacer inserted between the partition walls 13, and the through hole 1
This determines the width of 4.

17 is a mirror surface.

The width 1 of the partition wall 13 is formed to be as narrow as possible. In addition, θ
is the inclination angle, L1 is the opening width of the recess 12, and L2 is the width of the through hole 14. It goes without saying that in this embodiment as well, the absorption efficiency is determined by the relationship among the opening length L1, the depth d1 of the sloped portion, and the slope angle θ. The functions and effects of the embodiment shown in FIGS. 9 and 10 are the same as those of the embodiment shown in FIG. 5.

Furthermore, the pattern of the recesses formed by the partition walls used in this invention is not limited to hexagons or triangles, but may be any combination of regular polygons; in short, the pattern reflects the solar radiation energy incident on each recess. It is sufficient to focus the light a few times and introduce it into the through hole. Finally, the numerical range disclosed in this invention will be explained in more detail.

In order to efficiently capture and utilize low-density electromagnetic wave energy such as solar energy, it is generally believed that condensing it with a reflector is effective, but there is no practical way to do so. The reflectance of a reflector is limited to around 90%, and the accuracy of the curvature and tracking mechanism when condensing light on a curved surface are also finite values, so the higher the condensing ratio, the less the amount of condensed energy. do.

In other words, it can be said that a material with a high condensing ratio has a low optical efficiency. The effectiveness of this invention is due to the structure in which the light collecting area (≠ loss area) S2 is smaller than the incident area S1.
The evaluation value is determined based on the light collection efficiency and utility value, that is, the light collection energy density, and this invention discloses the results of investigating the optimum range.

Regarding the ratio of side length and area, please refer to the third and fourth embodiments.
In the case of two-dimensional condensation like the LlSl moon in the figure, the relationship Lq-(-) holds true, and 1 as shown in Figures 9 and 10 of the example.
In dimensional focusing? o (Relationship 2-1, but within the practical scope of validity 0, in either case, it is included in the wishes stated in the claims.) Regarding the above points, as follows: An analysis example of practical performance evaluation will be shown to explain the present invention.

Optical efficiency: The ratio of incident light that is focused and reaches the condensing surface.Condensing rate: The ratio of the energy density of the condensing surface to the energy density of the incident surface.High condensing energy density means high energy utilization value. The condensing ratio represents the ratio of the loss area to the incident area.

Analysis conditions (1) The incident light is a parallel ray.

() The reflectance of the reflective mirror surface is 90%.

11) The gap between the absorber and the light introducing body is sufficiently smaller than the side length L1 of the incident surface and the side length L2 of the condensing surface.

Therefore, it becomes as follows. Focusing area Z Light receiving area = Loss area d〉0.5 and Tan θ = 0.2 From the analysis results, “゛ L, 2” L2 O. Since 4 has a practical appropriate value, from the above formula, 1 = 1L1~
5 is the optimal range.

Figure 12 shows the incident light introduction path using the above relationship as a specific example.
It is shown in FIG. 15, and the results are shown in Tables 1 to 2.

When the depth of the light introducing body is ~D7, the ratio of d is kept constant, and one different case [A-1] Ll ~ [A-4]
, and take the hub meter (· nθ).

When the table is shown as a graph, the two-dimensional light focusing case shown in FIG. 16a and the one-dimensional light focusing case shown in FIG. 16b are shown. In the figure - θ21
．． 0 case [A-4] and -θ0.5 case [A-
Part of 3]? <It becomes an inappropriate value in the range of 0.5. Another pattern is that D and Ll are constant and the ratio d force = 1
．． 25, case where ,2 is different [B-1] (17th
Table 5 and FIG. 18 show the results of the analysis for (see figure).

d Also, when D and Ll are constant and their ratio is 1 = 0.1, '
Table 6 and FIG. 20 show the results of analysis for case [B-2] (see FIG. 19) in which l − Ll−◆ ♂ L2 is different.

dAlso, when D and Ll are constant, the ratio is −9 which is the limit value.
- -LlO. Table 7 and FIG. 22 show the results of analysis for case [B-3] (see FIG. 21) in which L2 is different.

d Next, as another pattern, one is constant and Lid and L are respectively
Table 8 and FIG. 24 show the results of analysis for case [C] (see FIG. 23) in which the value of l is different.

L, Furthermore, from the above analysis results, for each case of 110L2d, 3, 2 in the range of appropriate values, -3? - - Results of analysis for cases [D-1], [D-2] and [D-3] with different L1 ratios are shown in Tables 9 to 11 and FIGS. 25 to 27.

Even when various other types are analyzed, the practical ones have characteristics close to those of the above-mentioned representative examples, except for special cases and cases where the condensing ratio is small.

When the practically effective range L is matched with the evaluation value below from the diagram showing each result, it is found that J is in the range of 1.7 to 5L2.

The practical effective range of the evaluation value is η0P1?0.8 In the case of primary light condensing { In a solar energy absorber that is an integrated structure of a light introduction plate and an absorption plate provided close to it, it differs somewhat depending on its installation conditions, i.e., fixed, semi-fixed, uniaxial tracking, biaxial tracking, etc.

In addition, the criteria for the evaluation value will vary depending on what percentage of scattered light is included or the spread angle in the case of sunlight, but in the structure of this invention, the optimal design value is selected within the disclosed appropriate value range. be done. Although the characteristics of the present invention have been explained by showing such a specific example, the present invention has discovered an effective structure and its optimum design value based on evaluation criteria that combine efficiency and density.

As explained in detail above, the present invention has a structure in which an energy introduction plate is installed on the surface of the absorber, and a large number of concave portions formed by a combination of regular polygons are formed by partition walls having an inclined angle. A through hole is formed in the center of each bottom, which is extremely small compared to the opening width of the recess, and energy is directed toward this through hole, and the entire surface is made to have a mirror surface by metal vapor deposition. It has the feature of being able to efficiently absorb into the absorbent body installed on the body〇

[Brief explanation of drawings]

Figure 1 is a spectral curve diagram of solar radiant energy, Figure 2
3 is a plan view of the energy introduction plate used in this invention, FIG. 4 is a partially enlarged sectional perspective view of FIG. 3, and FIGS. 5 to 8 show the operation of this invention. 9 and 10 are a plan view and a side sectional view showing an embodiment of the energy introduction plate of the present invention. Figures 11 to 27 (1 Diagrams for explaining the optimum values of this invention. In the figures, 1 is an energy introduction plate, 2 is a recess, 3 is a partition wall, 4 is a through hole, 5 is a mirror surface, and 6 is an absorption It is the body.

Claims (1)

[Claims] 1. In front of the solar radiant energy absorber, an energy introduction plate is installed with the entire surface as a mirror surface at a certain interval, and a large number of recesses are formed on the surface of the energy introduction plate by partition walls having opposing sloped surfaces, A through hole is formed at the bottom of each of the recesses, and the ratio of the opening length or side L_1 of the recess to the length or side L_2 of the through hole is 1.7 to 1.
5, the solar radiant energy absorber is characterized in that it absorbs solar radiant energy once irradiated without letting it escape.