CN107919848B - Annular linear Fresnel high-power condenser - Google Patents

Abstract

The invention discloses a ring-shaped linear Fresnel high-power concentrator, which mainly comprises a condensing lens, a condensing plane and a bracket. Its design method is as follows. The condensing lens 1 is a silver-plated condensing lens with annular distribution, and its shape is a circular truncated cone without an upper and lower bottom surface formed by a line segment of a fixed length rotating around an axis. 2 is the Fresnel lens (only the position is reserved, not shown), 3 is the condenser bottom bracket and bracket, including the mirror link structure to support the entire set of condensers. 4 is a condensing plane, and the light reflected by the condensing mirror is received by a photovoltaic cell 5 dedicated to high-power concentrating located in the center of the receiving disc. 6 is the connecting rod between the condensing plane and the bottom bracket of the condensing lens, and 7 is the connecting head connecting the biaxial condensing system. The concentrator has a large condensing ratio.

Description

A Ring Linear Fresnel High Power Concentrator

technical field

The invention belongs to the field of high-power concentrating photovoltaics, and also includes the field of photovoltaic photothermal comprehensive utilization. The invention relates to a point-condensed annular high-power concentrator and a point-condensed Fresnel lens high-power concentrator.

Background technique

In the solar energy concentrating utilization system, the choice of the concentrator directly affects the arrangement of the whole system. Different from non-concentrating photovoltaics and low-power concentrating photovoltaics, high-power concentrating photovoltaics have higher conversion rates and efficiencies. In addition to high conversion rate, high-power CPV also has the characteristics of small temperature coefficient, good grid matching (high daily power generation), environmental friendliness (small land occupation, comprehensive utilization of land), and strong efficiency improvement. First, the multi-junction III-V cells used in high-power concentrator photovoltaics can work at higher temperatures and maintain better efficiency, and each concentrator is equipped with a heat sink behind it, so the external temperature In the case of large changes, compared with crystalline silicon and thin film batteries, its own efficiency will not be greatly affected. It is estimated that the efficiency of concentrating photovoltaic cells is only one-third of that of crystalline silicon cells when the temperature increases by one degree. Therefore, high-power concentration has a great effect on the PV/T field. High-power condensers require corresponding high-power condensers, so trough condensers, tower condensers, and linear Fresnel condensers are all high-power condensers with good effects. The annular linear Fresnel proposed in this patent is improved from the linear Fresnel concentrator.

Patent content

The purpose of the annular linear Fresnel concentrator proposed in this patent is to change the light path and convert the linear condensing mode of the linear Fresnel concentrator to the point condensing mode, which will make the condensing ratio of the concentrator higher. Greatly improve. Each ring in the annularly distributed silver-coated condenser lens 1 is a circular truncated cone without upper and lower bottom surfaces formed by a line segment of a fixed length rotated around an axis. And each fixed-length line segment has a different position and inclination. The sun rays of normal incidence can be collected on the high-power photovoltaic cell 5 located in the center of the receiving disk through the annularly distributed reflector. The back of the photovoltaic cell 5 is equipped with a special radiator to take away the heat of the photovoltaic cell, which can reduce the temperature of the photovoltaic cell and improve the power generation efficiency. Other uses. Each annularly distributed silver-coated condenser lens 1 does not block each other, and for the line segment formed by the cross section of each annular condenser lens, the straight line formed by the top end point of the upper line segment and the bottom end point of the lower line segment is parallel to the rotation axis. To ensure that each annular condenser does not block each other. The entire device adopts dual-axis tracking with automatic tracking to ensure that the central axis of the entire device faces the sun and keeps the sun directly shining. In the center of the condenser, there is a Fresnel condenser lens whose optical axis is the symmetry axis of the whole device, and its diameter is the same as that of the part of the device without a reflector. The focal point of the Fresnel lens in the center of the condenser coincides with the focal point of the annular condenser, and both are on the receiving disk 5 . After the sunlight directly hits the annularly distributed reflector and the central Fresnel lens, it is reflected and refracted to the solar cell on the receiving plate 5, which can generate electricity. The back of the battery is cooled by a coolant, which can generate heat.

The beneficial effects of the present invention are:

1. Improve the light distribution path of the linear Fresnel concentrator, from linear to circular, and change the concentrator distributed along the surface from horizontal to vertical, which can save area.

2. After the light is irradiated on the solar cell by the reflector and the Fresnel lens, it can generate electricity, and the back of the solar cell is cooled by a coolant, which can generate heat energy.

3. High space utilization rate.

4. The light concentration ratio is high, and the energy density after the light is concentrated is large.

Q _n = -Htan2β _n

Description of drawings

Accompanying drawing 1 is the structure diagram of the device of the present invention. FIG. 2 is an optical path diagram of two annular mirrors at the edge of the present invention, and FIG. 3 is a detailed enlarged view of the optical path diagram.

Detailed ways:

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments

As shown in Figure 1, the entire device is symmetrical along the central axis. Each ring in the annularly distributed silver-coated condenser lens 1 is a circular truncated cone without upper and lower bottom surfaces formed by a line segment of a fixed length rotated around an axis. And each fixed-length line segment has a different position and inclination. The sun rays of normal incidence can be collected on the high-power photovoltaic cell 5 located in the center of the receiving disk through the annularly distributed reflector. The back of the photovoltaic cell 5 is equipped with a special radiator to take away the heat of the photovoltaic cell.

The annular linear Fresnel high-power concentrator is symmetrical along the central axis.

The annularly distributed reflector in the annular linear Fresnel high-power concentrator adopts a total reflection silver-plated surface to ensure high reflectivity.

The entire assembly needs to be equipped with an automatic tracking system to ensure that the plane where the solar panel 5 is located is vertical to the incident direction of sunlight.

The supporting structure needs to effectively support the mirror surface portion, and can withstand the influence of strong wind and sand and dust weather to a certain extent.

The mirror surface is thinner and thinner, and glass with higher strength needs to be used.

The mirror surface connection structure and the mirror surface need to be directly connected to ensure the structural strength.

All the parameters of the mirror surface are obtained by calculation.

Fig. 2 and Fig. 3 are the optical path diagrams of two mirrors on the edge, and the position of the mirror surface and the angle of inclination of each mirror are calculated as follows:

Let the most edge annular mirror surface be the nth annular mirror surface, and the inwards are the n-1th and n-2th pieces in turn, and the cross-sectional width of each mirror surface is D.

中心坐标为(x_n，y_n)，下边缘坐标为The coordinates of the upper edge of the nth mirror are

The center coordinates are (x _n , y _n ), and the lower edge coordinates are

Taking the horizontal projection of the center point of the nth mirror on the symmetry axis as the origin, establish a plane rectangular coordinate system along the horizontal and vertical directions;

Let the horizontal distance from the center of the nth annular mirror to the condensing point be Q _n , and the vertical distance be H _n

Let the center of the nth annular mirror be (Q _n , 0),

Then the coordinates of the upper edge of the nth mirror are

The abscissa of the lower edge of the nth mirror is

The abscissa of the upper edge of the n-1th mirror is the same as the abscissa of the lower edge of the nth mirror,

therefore

for

The abscissa of the center of the n-1th mirror is

Find its ordinate below,

Establish a straight line equation for the upper edge of the nth mirror:

Can be simplified to:

therefore

Then the ordinate of each mirror can be expressed by the following formula:

From the ordinate of the center of the n-1th mirror:

It can be concluded that:

From the equation of the straight line, we can get:

The ordinate of the center of the n-1th mirror can be derived:

From the geometric relationship, we can get:

β _n-1 -λ _n-1 +β _n-1 =90°

therefore:

2β _n-1 =90°+λ _n-1

λ _n-1 =2β _n-1 -90°

By the triangular relationship:

Available equation:

From the trigonometric relationship we get:

Q _n = -Htan2β _n

Bring in the iterative equation for the positions of two connected mirrors:

Therefore, these three parameters of each of the remaining mirrors can be obtained from the height from the condensing point of the most edge mirror, the width of the mirror cross-section and the inclination angle.

Claims (3)

1. A ring-shaped linear Fresnel high-power concentrator is characterized in that: a silver-coated condenser lens (1) comprising an annular distribution, a central Fresnel lens (2), a receiving disk (5), and a support and a motor Connected structure one (3), structure two (4), structure three (6), structure four (7); each ring in the annularly distributed silver-plated condenser lens (1) is formed by a line segment of a fixed length around the axis Rotate to form a circular table without upper and lower bottom surfaces, and the position and inclination angle of each fixed-length line segment are different; each shape of the annularly distributed silver-coated condenser (1) is different, but it can reflect the vertically incident light to the receiving disc (5) On the photovoltaic cell in the center; each annularly distributed silver-coated condenser (1) does not block each other, and for the line segment formed by the cross-section of each annular condenser, the top end point of the upper line segment and the bottom end point of the lower line segment are The straight line formed is parallel to the rotation axis to ensure that each annular condenser does not block each other; there is a Fresnel condenser lens in the center of the condenser whose optical axis is the symmetry axis of the whole device, and its diameter is the same as the part of the device without mirrors; The focal point of the Fresnel lens in the center of the optical device coincides with the focal point of the annular condenser, and both are on the receiving disk (5); Assuming that the most edge ring mirror is the nth ring mirror, and the inwards are the n-1th and n-2th blocks in turn, then the iterative equation for the positions of the two connected mirrors is: Among them, the height from the condensing point, the mirror cross-section width and the inclination angle of the most edge annular mirror are H, D, and β _n respectively, then the distance from the condensing point, the mirror cross-section width and the inclination angle of the most edge mirror can be obtained. These three parameters for each of the remaining mirrors. 2. A kind of annular linear Fresnel high-power concentrator according to claim 1, characterized in that: the back of the photovoltaic cell is equipped with a radiator to take away the heat of the photovoltaic cell, which can reduce the temperature of the photovoltaic cell , improve the power generation efficiency, and the heat taken away can also be used to generate domestic hot water or used for refrigeration. 3. A kind of annular linear Fresnel high-power concentrator according to claim 1 is characterized in that: the whole device adopts dual-axis tracking with automatic tracking to ensure that the central axis of the whole device is facing the sun, and keeps direct sunlight. .

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