CN107166757A - The circular Fresnel type solar collecting device of point focusing twice - Google Patents

Abstract

The invention relates to a double point focusing circular Fresnel type solar collector, comprising: a heat collector, a secondary concentrator and a bracket, the heat collector includes a primary concentrator and a heat collecting tube, the primary concentrator It is a circular Fresnel reflector; the secondary concentrator is a rotating parabolic reflector or a circular Fresnel reflector; the heat collecting tube is located between the primary concentrator and the secondary concentrator, and the heat collecting tube is at the same time At the focal point of the primary concentrator and the secondary concentrator; the bracket is used to support the primary concentrator, secondary concentrator and heat collecting tube. The invention provides a solar energy collection device, adding a secondary concentrator as a rotating parabolic reflector, and the heat collector is located between the secondary concentrator and the primary concentrator, and is on the focus point of the secondary concentrator , can reflect the sunlight passing through the heat collector to the circular Fresnel reflector again, and then gather it to the heat collector again, with less light loss and high heat collection efficiency.

Description

Twice point-focused circular Fresnel-type solar collector

technical field

The invention relates to a double point focusing circular Fresnel type solar energy collection device, in particular to a solar energy collection device with high light-to-heat conversion efficiency.

Background technique

The heat collector is a device that controls the optical path of radiated parallel rays through the reflective surface, increases the heating power of the object, and thereby increases the temperature of the object. From the perspective of optical path control and focusing, there are two types of focusing and non-focusing; among them, the heating power of the focusing collector is greater than that of the non-focusing collector, which can achieve a higher heating temperature. For focusing collectors, there are mainly two types: line focusing and point focusing. Line focusing means that parallel light rays are focused into a line; point focus means that parallel light rays are focused into a point shape.

Condensation ratio is an important technical index of the light-concentrating reflective surface. Different concentration ratios will affect the heating power of the heated object and the temperature range that can be reached. The focusing ratio mainly depends on the form of the focusing reflective surface. According to whether the optical path penetrates the reflective surface, there are reflective and transmissive. Reflective focusing reflectors currently mainly include parabolic and Fresnel types; according to the difference between line focus and point focus, there are paraboloid and line focus Fresnel reflectors; rotating paraboloids and circular Fresnel reflectors. As a result, two technical routes of trough-type concentrating and dish-type concentrating have been produced in engineering, and related technical routes, products and applications have been produced.

There are direct type and indirect type for the absorption of radiation energy by the heated object in the collector; the direct type is to use the medium to directly absorb radiation energy and convert it into an increase in its own temperature; the indirect type is to use the coating to absorb radiation energy, and the coating temperature rises. After high, the heat is transferred to the heated medium, thereby increasing the temperature of the medium.

The technical improvement scheme of the direct absorption type is mainly implemented to increase the concentration ratio of the incident light path, and the concentration ratio of different types of concentrators is very different: the range of concentration ratio of the rotating parabolic concentrator is very high , about 500 to 3000; the concentration ratio of the parabolic cylindrical collector is about 20 to 80; the concentration ratio of the linear Fresnel lens collector is about 6 to 30; the circular Fresnel lens The light concentration ratio range of the concentrating heat collector is relatively high, about 100 to 1000; the light concentration ratio range of the linear Fresnel reflector light concentrating heat collector is about 15 to 50. Therefore, with different concentrators or combinations of concentrators, the light collection efficiency of the device also has a large difference. This patent is mainly aimed at collecting and utilizing this part of the light, thereby improving the optical/photothermal efficiency of the device.

Contents of the invention

The technical problem to be solved by the present invention is: in order to solve the problems of high unit cost and low heat collection efficiency of the existing medium-temperature solar collectors, the present invention provides a circular Fresnel type solar collector with double point focusing device, on the basis of the existing technology, a secondary concentrator is added, the secondary concentrator is a rotating parabolic reflector or a circular Fresnel reflector, and the heat collecting tube is located between the secondary concentrator and the primary concentrator In between, and at the focal point of the secondary concentrator, the sunlight passing through the heat collecting tube can be reflected to the primary concentrator again, and then collected to the heat collector again, with less light loss and high heat collection efficiency.

The technical solution adopted by the present invention to solve the technical problems is: a circular Fresnel type solar energy collection device with twice point focusing, comprising: a heat collector, a secondary concentrator and a support,

The heat collector includes a primary concentrator and a heat collecting tube, the primary concentrator is a circular Fresnel reflector, and the circular Fresnel reflector has a focal point;

The secondary light concentrator is a rotating parabolic reflector or a circular Fresnel reflector, and the secondary light concentrator has a focal point;

The heat collecting tube is located between the primary concentrator and the secondary concentrator, and the heat collecting tube is at the focal point of the primary concentrator and the secondary concentrator at the same time, and the heat collecting tube carries an energy absorbing medium;

The bracket is used to support the primary concentrator, the secondary concentrator and the heat collecting tube.

Specifically, the above-mentioned heat collecting tube is ellipsoidal, spherical or square.

Specifically, the above-mentioned heat collecting tube is a vacuum tube, including an outer tube and an inner tube, the interlayer between the outer tube and the inner tube is a vacuum, and the inner tube carries an energy-absorbing medium.

Specifically, the above-mentioned outer tube and inner tube are light-transmitting tubes.

Specifically, the above-mentioned outer tube is made of glass, PMMA or PC.

Specifically, the inner tube is made of glass, PMMA or PC.

Specifically, a solar tracking device is also included.

The beneficial effects of the present invention are:

(1) The present invention provides a circular Fresnel type solar collector with two point focussing. On the basis of the prior art, a secondary concentrator is added, and the secondary concentrator is a rotating parabolic reflector Or a circular Fresnel reflector, the heat collecting tube is located between the secondary concentrator and the primary concentrator, and is at the focal point of the secondary concentrator, which can pass the sunlight passing through the heat collecting tube through the secondary concentrator The light from the secondary concentrator is reflected to the primary concentrator again, and then collected to the heat collection tube again, with less light loss and high heat collection efficiency.

(2) the present invention provides a kind of circular Fresnel type solar energy collection device of twice point focusing, and outer layer tube and inner layer tube are all light-transmitting tubes, can make after circular Fresnel reflector focusing The light is absorbed by the heat collecting tube, and the unabsorbed light will pass through the heat collecting tube to the secondary concentrator, convert into parallel light, and be refocused by the primary concentrator to be absorbed in the heat collecting tube, further improving the solar energy The heat collection efficiency of the collection device.

(3) The present invention provides a circular Fresnel type solar collector with two points of focus. On the basis of the prior art, a secondary concentrator is added, which can effectively prevent sandstorms, rain and snow from affecting the heat collecting tubes. The corrosion effectively prolongs the service life of the heat collecting tube and prolongs the service life of the solar energy collection device.

Description of drawings

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

Fig. 1 is a kind of rotating parabolic reflector of the present invention strengthens the optical path schematic diagram of circular Fresnel reflector point focusing solar energy collecting device;

Fig. 2 is a structural representation of a rotating parabolic reflector of the present invention enhancing a circular Fresnel reflector point-focused solar collection device;

Fig. 3 is a kind of circular Fresnel reflector of the present invention strengthens the light path schematic diagram of circular Fresnel reflector point focusing solar energy collecting device;

Fig. 4 is a structural representation of a circular Fresnel reflector enhanced circular Fresnel reflector point-focused solar collector of the present invention;

Fig. 5 is the preferred local structure schematic diagram of a circular Fresnel type solar energy collector heat collecting tube of a kind of twice point focusing of the present invention;

In the figure: 1. heat collector, 11. primary concentrator, 12. heat collecting tube, 2. bracket, 3. secondary concentrator, 121. outer tube, 122. inner tube, 4. solar tracking device .

detailed description

The present invention is described in further detail now in conjunction with accompanying drawing. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, so they only show the configurations related to the present invention.

Example 1

As shown in Figure 2, a rotating parabolic mirror enhanced rotating parabolic mirror point-focused solar collection device, including: a heat collector 1, a secondary concentrator 3 and a bracket 2

The heat collector 1 includes a primary concentrator 11 and a heat collecting tube 12, the primary concentrator 11 is a circular Fresnel reflector, and the circular Fresnel reflector has a focal point;

The secondary concentrator 3 is a rotating parabolic reflector, and the secondary concentrator 3 has a focal point;

The heat collection tube 12 is located between the primary concentrator 11 and the secondary concentrator 3, and the heat collection tube 12 is at the focal point of the primary concentrator 11 and the secondary concentrator 3 at the same time, and the heat collection tube 12 is loaded with energy absorption medium;

The bracket 2 is used to support the primary concentrator 11 , the secondary concentrator 3 and the heat collecting tube 12 .

A kind of rotating parabolic reflector of the present invention strengthens the circular Fresnel reflector point-focusing solar collection device, its light path is shown in Figure 1, and the circular Fresnel reflector of primary concentrator 11 is irradiated at first by parallel light Above, the light is focused by the circular Fresnel reflector of the primary concentrator 11 and gathered in the heat collecting tube 12, and the light transmitted through the heat collecting tube 12 reaches the secondary concentrator 3, and the secondary concentrator 3 will receive The light is transformed into parallel light, which is directly incident on the circular Fresnel reflector of the primary concentrator 11 for refocusing until the light is completely absorbed.

Example 2

As shown in Figure 4, a circular Fresnel reflector enhanced rotating parabolic reflector point-focused solar collection device, including: heat collector 1, secondary concentrator 3 and support 2

The heat collector 1 includes a primary concentrator 11 and a heat collecting tube 12, the primary concentrator 11 is a circular Fresnel reflector, and the circular Fresnel reflector has a focal point;

The secondary concentrator 3 is a circular Fresnel reflector, and the secondary concentrator 3 has a focal point;

The heat collection tube 12 is located between the primary concentrator 11 and the secondary concentrator 3, and the heat collection tube 12 is at the focal point of the primary concentrator 11 and the secondary concentrator 3 at the same time, and the heat collection tube 12 is loaded with energy absorption medium;

The bracket 2 is used to support the primary concentrator 11 , the secondary concentrator 3 and the heat collecting tube 12 .

A kind of circular Fresnel reflector of the present invention strengthens circular Fresnel reflector point-focusing solar energy collecting device, its optical path is shown in Figure 3, and parallel light first irradiates the circular Fresnel of concentrator 11 On the Fresnel reflector, the light is focused by the circular Fresnel reflector of the primary concentrator 11 and gathered in the heat collecting tube 12, and the light transmitted through the heat collecting tube 12 reaches the secondary concentrator 3, and the secondary concentrator 3 The received light is converted into parallel light, which is directly incident on the circular Fresnel reflector of the primary concentrator 11 for refocusing until the light is completely absorbed.

In a specific embodiment, the heat collecting tube 12 is ellipsoidal, spherical or square. In this specific embodiment, the section of the heat collecting tube 12 is spherical, and has a pipeline for carrying the energy absorbing medium, including a feed pipe 123 and a discharge pipe 124. The pipeline is used to carry the energy absorbing medium on the one hand, and the other On the one hand, it is used to support the heat collecting tube 12 so that it is at the focal point of the primary concentrator 11 and the secondary concentrator 3 .

In a specific embodiment, the solar energy collection device further includes a solar tracking device 4 . It is mainly used to track sunlight, so that the solar energy collection device is always in the best light-to-heat conversion state. Its specific form can be any existing solar tracking device, as long as it can meet the requirements of tracking sunlight.

In a specific embodiment, as shown in Figure 5, the heat collecting tube 12 is a vacuum tube, including an outer tube 121 and an inner tube 122, the interlayer between the outer tube 121 and the inner tube 122 is a vacuum, and the inner tube 122 carries an energy absorbing medium. The feed pipe 123 and the discharge pipe 124 pass through the outer pipe 121 and the inner pipe 122 in turn respectively, and reach the inside of the inner pipe 122 . Wherein the angle between the feed pipe 123 and the discharge pipe 124 is 0°-180°, which is 0° in this embodiment. Of course, the angle between the feed pipe 123 and the discharge pipe 124 can be selected from 30°, 45°, 60°, 90°, 120°, 135° and 150° according to the actual situation.

Specifically, both the outer tube 121 and the inner tube 122 are light-transmitting tubes.

Preferably, the outer tube 121 is made of glass, PMMA or PC.

Preferably, the inner tube 122 is made of glass, PMMA or PC.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (7)

1. A circular Fresnel type solar collection device with twice point focus, is characterized in that comprising: heat collector, secondary concentrator and support, The heat collector includes a primary concentrator and a heat collecting tube, the primary concentrator is a circular Fresnel reflector, and the circular Fresnel reflector has a focal point; The secondary light concentrator is a rotating parabolic reflector or a circular Fresnel reflector, and the secondary light concentrator has a focal point; The heat collecting tube is located between the primary concentrator and the secondary concentrator, and the heat collecting tube is at the focal point of the primary concentrator and the secondary concentrator at the same time, and the heat collecting tube carries an energy absorbing medium; The bracket is used to support the primary concentrator, the secondary concentrator and the heat collecting tube. 2. A circular Fresnel type solar collector with double point focusing as claimed in claim 1, characterized in that: the heat collecting tube is in the shape of an ellipsoid, a sphere or a square. 3. A kind of circular Fresnel type solar collector with double point focusing as claimed in claim 1 or 2, characterized in that: the heat collecting tube is a vacuum tube, comprising an outer layer tube and an inner layer tube, and the outer layer The interlayer between the tube and the inner tube is a vacuum, and the inner tube carries an energy-absorbing medium. 4. A circular Fresnel-type solar collector with double point focusing as claimed in claim 3, characterized in that: both the outer tube and the inner tube are light-transmitting tubes. 5 . The circular Fresnel type solar collector with double point focusing as claimed in claim 4 , wherein the material of the outer tube is glass, PMMA or PC. 5 . 6. A circular Fresnel-type solar collector with double point focusing as claimed in claim 4 or 5, characterized in that: the material of the inner tube is glass, PMMA or PC. 7. A circular Fresnel-type solar collector with double point focusing as claimed in claim 1, further comprising a solar tracking device.