CN102141676B - Total reflection-based inverse stair solar condensing body - Google Patents

Abstract

An inverted stair-shaped solar concentrator based on total reflection, including an inverted stair-shaped quasi-lower plane made of an optically dense medium, the angle of the step is a right angle, and the angle α between the upper plane and the horizontal plane is equal to the optically dense medium and the horizontal plane. The critical angle at which total reflection occurs in an optically sparse medium (surrounding air). The solar concentrator produced according to this principle is only composed of one optical material, which effectively solves the current problem of short life of the concentrator due to the easy fall off of the reflective film on the back of the glass and the decrease in concentrating efficiency caused by the absorption of light by the reflective film. In order to solve technical problems, the self-cleaning performance of the concentrator is improved by using a plane as the upper surface for receiving sunlight. Driven by a high-precision automatic tracking system, the sunlight is vertically incident on the receiving slope, and the shape of the concentrator can be changed according to actual needs to directly realize line or point concentration.

Description

Inverted staircase solar concentrator based on total reflection

technical field

The invention relates to the field of parallel light concentrating, in particular to an inverted stair-shaped solar concentrator based on total reflection.

technical background

One of the obstacles to the promotion and application of solar energy is that the energy density is too low (1 kW/square meter), and it is one of the ways to effectively increase the solar energy density by concentrating light. However, there are specific practical problems in the application of the two basic concentrating methods of reflective and transmissive: the most commonly used method in reflective concentrators is to use the method of coating the reflective layer on the back of the glass material to realize solar energy concentration. The device has the problem that the reflective film falls off in the harsh outdoor environment; in the transmissive concentrator, the Fresnel lens is used as the concentrator to achieve sunlight concentration, but the device has always had poor self-cleaning performance And technical problems such as easy aging, which directly affect the application and promotion.

The invention patent "quasi-planar side-firing solar concentrator based on total reflection" can realize solar concentrating under the condition of total reflection, although the concentrator only needs glass as a material, which effectively solves the current concentrating problem caused by the falling off of the reflective film. The problem of short service life of the optical device also avoids the problem of the reduction of light collection efficiency caused by the absorption of light by the reflective film, and can change the shape of the light collector according to actual needs to directly realize line or point light concentration, but in actual processing and application However, there are still the following problems: due to the optical processing of the quasi-plane composed of jagged slopes, the cost increases and the poor self-cleaning performance caused by the unevenness, and the attenuation effect of the glass material on the passage of sunlight after total reflection It is also not negligible. For example, when the distance of 1 meter is transmitted in the glass, the intensity of sunlight is reduced to about 36.2% of the original.

Contents of the invention

The object of the present invention is to overcome the above-mentioned shortcomings, and provide a kind of inverted stair-shaped solar concentrator based on total reflection, which guides sunlight from the side of the concentrator according to the principle of total reflection. It effectively solves the problem of cost increase caused by optical processing of serrated slopes to form quasi-planes and poor self-cleaning performance caused by non-smooth structures; and the lower horizontal surface that constitutes the refraction surface is processed into several inverted staircase-like steps according to needs, reducing the overall cost. The attenuation loss of sunlight in the glass material after reflection also reduces the thickness and weight of the concentrator.

In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: it comprises an inverted stair-shaped lower quasi-plane and an upper plane made of optically dense media, the angle of the inverted stair-shaped step-type forming the lower quasi-plane is a right angle, and the upper The angle α between the plane and the horizontal plane is the critical angle when total reflection occurs between the optically denser medium and the optically rarer medium.

The light-dense medium is made of glass material, and the light-dense medium is natural environment atmosphere.

The linear concentration of solar energy is realized when the inverted stair-like step is a rectangular structure.

The inverted stair-like step is an isosceles trapezoid, and when the angle between its two waists and the lower side is the critical angle α, the point concentration of solar energy can be realized.

The present invention is different from the light receiving body in the front of the light collecting body in the reflection type light concentrating, and also different from the light receiving body in the back of the light collecting body in the transmission type light collecting, but the light receiving body is on the side of the light collecting body. Through the inverted stair-shaped concentrator, under the condition that the high-precision automatic tracking system ensures that the light-receiving surface is vertically facing the sunlight, the parallel light total reflection phenomenon is used, which not only effectively realizes the concentrating sunlight from the side to the line or point In addition, compared with the invention patent, the upper surface of the concentrator receiving sunlight is a plane, which effectively solves the cost increase caused by the quasi-plane formed by the jagged inclined surface of optical processing and the self-cleaning performance brought by the non-smooth structure. Poor problem; in addition, the lower horizontal plane that constitutes the refraction surface is processed into several inverted staircase-like right-angled steps according to needs, which not only reduces the attenuation loss of sunlight in the glass material after total reflection, but also reduces the thickness of the concentrator and weight, and reduce the processing difficulty of the concentrator itself.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is the top view of concentrator when line concentrating;

Fig. 3 is the top view of concentrator when point concentrating;

Fig. 4 is a schematic diagram of the light path of total reflection point concentrating light.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, the present invention comprises the inverted stair-shaped concentrator 1 that is made of white glass, and the included angle between its upper plane 3 (light-receiving surface) and horizontal plane 4 (total reflection surface) is the lower plane of the white glass 1 material and the natural environment The critical angle α when total reflection occurs at the atmosphere-2 interface, and the steps forming the inverted staircase shape are at right angles. The number of steps is related to the processing cost, the attenuation requirements of sunlight in the optically dense medium, and the reduction of the weight of the concentrator itself. The light collector 1 is driven by a high-precision automatic tracking system to ensure that the sunlight is vertically incident on the light-receiving plane 3 and enters the light collector; So its corresponding critical angle α=33.7 ^0, ; and because the angle between the receiving plane and the horizontal plane is the critical angle when the sunlight is emitted from the glass concentrator (optical dense medium) to the air (optical sparse medium), so at this time When total reflection occurs, all incident light rays A, B, C, and D will converge into E, and exit from the side of the concentrator, so as to achieve the goal of converging sunlight.

Referring to Fig. 2, when the photoreceptor is linear, the concentrator planes are rectangular or trapezoidal respectively, and the width and length of the rectangle determine the length and intensity of linear concentrating light respectively.

Referring to Figure 3, when the photoreceptor is in the shape of a dot, the concentrator plane is an isosceles trapezoid, the angle between its two waists and the lower side is the critical angle α, and the concentration intensity is related to the length and base length of the trapezoid. Referring to Figure 4, parallel sunlight travels from left to right along the bottom surface of the concentrator according to the total reflection theorem, and then forms total reflection at the interface formed by the two waists of the isosceles trapezoid, and then continues along these two interfaces. Advance, and finally shoot out from the upper base of the isosceles trapezoid in the direction parallel to the isosceles surface. Therefore, the light-receiving body in the point spotlight should be as close as possible to the upper bottom of the isosceles trapezoid, otherwise the concentrated light will diverge as the distance from the upper bottom increases, resulting in a decrease in the concentrated light intensity.

Claims (4)

1. the Salar light-gathering of falling stair shape body based on total reflection, it is characterized in that: comprise the condensing body of making by optically denser medium (1) material, described condensing body is made of the surface level of falling the stair shape (4) and last plane (3), the angle of the step of falling the stair shape of described formation surface level (4) is the right angle, the angle of plane on it (3) and surface level (4) is the critical angle α of the surface level (4) of condensing body when with optically thinner medium (2) interface total reflection taking place, sunshine is vertically injected plane (3) and total reflection phenomenon will be taken place when entering condensing body, all incident ray (A, B, C, D) all will accumulate the emergent ray (E) of level, from the side outgoing of condenser, thereby reach the target that sunshine converges; Described optically thinner medium (2) is the physical environment atmosphere.

2. the Salar light-gathering of falling the stair shape body based on total reflection according to claim 1 is characterized in that: described optically denser medium (1) is made by glass material.

3. the Salar light-gathering of falling the stair shape body based on total reflection according to claim 1 is characterized in that: the step of falling the stair shape of described surface level (4) is a rectangular configuration, realizes the line optically focused of sun power.

4. the Salar light-gathering of falling the stair shape body based on total reflection according to claim 1 is characterized in that: the step of falling the stair shape of described surface level (4) is an isosceles trapezoid, and its two waist is critical angle α with following angle, realizes the some optically focused of sun power.

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