CN210197745U

CN210197745U - Large-scale point focusing Fresnel type solar light-gathering and heat-collecting system

Info

Publication number: CN210197745U
Application number: CN201920884917.0U
Authority: CN
Inventors: Jian Yan; 颜健; Xiao Wang; 王晓; Shan Zhang; 张珊; Lijuan Yang; 杨利娟; Sijia Liu; 刘思嘉; Xue Wang; 王雪; Yili Wang; 王宜荔
Original assignee: Hunan University of Science and Technology
Current assignee: Hunan University of Science and Technology
Priority date: 2019-06-13
Filing date: 2019-06-13
Publication date: 2020-03-27
Anticipated expiration: 2029-06-13

Abstract

The utility model discloses a large-scale point focusing Fresnel type solar light-gathering and heat-collecting system, which comprises a light-gathering device, a double-shaft tracking platform, a heat absorber and a tracking controller; the condenser comprises a fixed frame, a plurality of Fresnel lenses and a reflection unit; the Fresnel lens and the heat absorber are fixed on the fixed frame, and the Fresnel lens is arranged right opposite to the sun; a reflection unit is arranged below each Fresnel lens, and the reflection unit can reflect the sunlight focused by the Fresnel lens to the heat absorber; the fixed frame is fixedly installed on the double-shaft tracking platform, and a double-shaft tracker of the double-shaft tracking platform is connected with the tracking controller. The utility model discloses simple structure, with low costs, bear rigidity good, realized the application of small size fresnel lens on high-power level solar energy spotlight thermal-arrest system, its biax that adopts parallel connection link mechanism to realize the spotlight ware is trailed, has further reduced solar energy spotlight thermal-arrest system's manufacturing and installation cost.

Description

Large-scale point focusing Fresnel type solar light-gathering and heat-collecting system

Technical Field

The utility model belongs to light-concentrating solar thermal energy utilization field especially relates to a fresnel formula solar energy spotlight solar collecting system of large-scale point focusing.

Background

Solar energy is a clean, environmentally friendly, abundant and widely distributed renewable energy source. The concentrated solar heat utilization is an important way for developing and utilizing solar energy resources, not only can provide heat energy for places such as industry and families, but also can be further coupled and butted with conventional steam turbine power generation equipment to realize the conversion from solar light energy to electric energy, and the scheme is considered as an important way for solving the problems of energy shortage and environmental pollution. The working principle of solar thermal power generation is as follows: the solar radiation energy is collected in the cavity receiver by the condenser, so that the fluid working medium in the metal coil pipe in the cavity receiver is heated, the heat engine is driven by the thermal working medium to do work, the generator set is driven to generate electricity, and the solar radiation energy and the heat storage system can be organically combined with a conventional thermal power station, so that continuous and stable electricity generation is realized, and the solar radiation energy and heat storage system has incomparable advantages compared with other renewable energy power generation modes.

The solar light-gathering and heat-collecting system is a hardware basis for high-grade solar heat utilization, and common light-gathering modes include mirror reflection type light-gathering systems such as a parabolic dish type reflection light-gathering device, a parabolic trough type reflection light-gathering device and a tower type heliostat. The disadvantages of the prior art are that the large-scale reflecting mirror surface is formed by splicing a plurality of mirror surface units, and not only is the manufacturing precision of a single reflecting mirror surface high, but also the strict integral installation precision requirement is required to be ensured. Therefore, the manufacturing and installation costs of the specular reflection condenser are high, and the economical efficiency is to be improved. How to design a solar light-gathering and heat-collecting system with low energy consumption and low cost becomes the main research direction of the solar heat utilization at present. Fresnel lens gathers light through the light refraction, and it can adopt optical plastics to carry out mould shaping manufacturing, has the machining precision height and the low advantage of batch production cost, and optical plastics is the light material moreover, can reduce the demand of condensing system to frame structure rigidity, so Fresnel lens is used in solar energy spotlight thermal-arrest field. However, due to the limitations of dispersion and optical efficiency, the aperture of the fresnel lens is usually small, which is difficult to meet the requirements of a high-power grade solar energy concentrating and heat collecting system.

On the other hand, a solar light-gathering and heat-collecting system with high energy density generally needs a double-shaft tracking device, so that the axis of a light collector is accurately aligned with the position of the sun, and the efficient gathering of sunlight is realized. The tracking mode is two enough shafts, and the azimuth-pitching, pitching-rolling, spinning-pitching and polar shaft modes are four typical two-shaft tracking modes, but the traditional two-shaft tracking device generally adopts a gear transmission structure, so that the self weight is large, the requirement on the manufacturing precision of the gear transmission device is high, and the manufacturing cost of the whole light-gathering system is not reduced. In fact, as a general light-gathering heat collector, a slight tracking error of the condenser is allowable, as long as the control is within a reasonable range. Therefore, as a link mechanism with lower cost, especially a parallel link mechanism with excellent rigidity to realize the double-axis tracking of the condenser, the link mechanism is a very important innovation aspect, and the manufacturing and installation cost of the whole solar light-gathering and heat-collecting system can be further reduced.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model provides a simple structure, with low costs, it is good to bear rigidity, and can gather large tracts of land solar energy and convert into the large-scale point focusing fresnel formula solar energy spotlight solar energy collecting system of heat energy, it has realized the application of small area fresnel lens in the aspect of high-power level solar energy spotlight solar energy collecting system, it adopts the biax tracking that rigidity is excellent, low-cost parallel link mechanism realizes the spotlight ware, whole solar energy spotlight solar energy heat collecting system's manufacturing and installation cost have further been reduced.

The utility model adopts the technical proposal that: a large point focusing Fresnel type solar light-gathering and heat-collecting system comprises a light collector, a double-shaft tracking platform, a heat absorber and a tracking controller; the condenser comprises a fixed frame, a plurality of Fresnel lenses and a reflecting unit; the Fresnel lens and the heat absorber are fixed on the fixed frame, and the Fresnel lens is arranged right opposite to the sun; a reflection unit is arranged below each Fresnel lens, and the reflection unit can reflect the sunlight focused by the Fresnel lens to the heat absorber; the fixed frame is fixedly installed on the double-shaft tracking platform, the double-shaft tracking platform is provided with a double-shaft tracker, the double-shaft tracker is connected with the tracking controller, and the tracking controller can control the fixed frame to face the sun.

In the large point focusing fresnel type solar light-gathering and heat-collecting system, the reflection unit comprises a convex lens and a plane mirror, the convex lens is fixedly arranged right below the center of the fresnel lens through an adjusting seat I, the image space focus of the fresnel lens is superposed with the object space focus of the convex lens, and the optical axes of the fresnel lens and the convex lens are superposed; the plane mirror is fixed under the corresponding convex lens through the adjusting seat II, and sunlight is reflected to the inside of the heat absorber through the adjusting seat II.

In the large point focusing fresnel solar light-gathering and heat-collecting system, the reflecting unit is an elliptical reflecting mirror, the elliptical reflecting mirror is fixedly arranged under the fresnel lens through the adjusting seat I, one focus of the curved surface of the elliptical reflecting mirror is superposed with the image focus of the fresnel lens, and the other focus of the curved surface of the elliptical reflecting mirror is positioned at the center of a light receiving window of a secondary light-gathering device at the front end of the heat absorber.

In the large point focusing fresnel type solar light-gathering and heat-collecting system, the double-shaft tracking platform comprises a double-shaft tracker and a supporting platform, the fixed frame is mounted on the supporting platform, and the double-shaft tracker comprises a driving motor, a T-shaped guide groove I and a T-shaped guide groove II; the driving motor comprises a motor I, a motor II and a motor III, the motor I, the motor II and the motor III are respectively connected with the tracking controller, and the motor I and the motor II are arranged at two ends of the T-shaped guide groove I; the motor III is arranged at one end of the T-shaped guide groove II; the T-shaped guide groove I and the T-shaped guide groove II are horizontally arranged in parallel and oppositely; a screw rod III is arranged in the T-shaped guide groove II and is fixedly connected with an output shaft of the motor III; the section of the screw rod III, where the midpoint is located, is taken as an interface and divided into two sections with equal length, the turning directions of threads on the two sections of screw rods are opposite, the two sections of screw rods are respectively matched with the internal thread holes of the hinged sliding block I and the hinged sliding block II through screw pairs, the hinged sliding block I and the hinged sliding block II are respectively hinged with one end of the two connecting rods I, the hinged sliding block I and the hinged sliding block II are both in T-shaped structures, and the T-shaped structures are matched with the T-shaped guide groove II; the other ends of the two connecting rods I are hinged with the rotating block; the rotating block is hinged with the bottom of the supporting platform, and the central lines of the two hinge pairs of the rotating block are vertical;

a support seat is arranged in the middle of the T-shaped guide groove I, the support seat divides the T-shaped guide groove I into two sections with equal length, a screw rod I and a screw rod II are respectively arranged in the two sections of the T-shaped guide groove I, and the screw rod I and the screw rod II are supported through the support seat in the T-shaped guide groove I; the screw rod I and the screw rod II are respectively matched with threaded holes of the spherical hinge sliding block I and the spherical hinge sliding block II through screw pairs; the shapes of the spherical hinge sliding block I and the spherical hinge sliding block II are both T-shaped structures, and the T-shaped structures are matched with the internal T-shaped grooves of the T-shaped guide grooves I; the spherical hinge sliding block I and the spherical hinge sliding block II are both provided with spherical hinge seats, and are respectively connected with the ball head connecting rod I and the ball head connecting rod II through spherical hinge pairs; the other ends of the ball head connecting rod I and the ball head connecting rod II are both provided with ball heads and are respectively connected with two ball hinge seats at the bottom of the supporting platform in a ball hinge pair mode; the two spherical hinge seats and the rotating block at the bottom of the supporting platform are arranged in a triangular shape.

In the large point focusing Fresnel type solar light-gathering and heat-collecting system, the adjusting seat II comprises a T-shaped connecting plate II, a mirror surface supporting seat and a set screw, the bottom end of the T-shaped connecting plate II is fixedly connected with a through hole of a supporting upright post of the fixed frame through a U-shaped groove through a bolt, and the height position of the T-shaped connecting plate II is adjusted through the U-shaped groove; the other end of the T-shaped connecting plate II is provided with a spherical hinge seat, the mirror surface supporting seat is L-shaped, one end of the mirror surface supporting seat is provided with a ball head, the ball head is installed in the spherical hinge seat, and the spherical hinge seat is provided with a plurality of set screws for fixing the spatial pose of the mirror surface supporting seat; the other end of the mirror surface supporting seat is welded with a mirror surface mounting plate.

In the large point focusing Fresnel type solar light-gathering and heat-collecting system, the adjusting seat I comprises a T-shaped connecting plate I, a ball head connecting plate and a mounting seat, a U-shaped groove is formed in a bottom plate of the T-shaped connecting plate I, the U-shaped groove is fixedly connected with a through hole of a supporting upright post of the fixed rack through a bolt, and the height position of the T-shaped connecting plate I is adjusted through the U-shaped groove; a vertical plate of the T-shaped connecting plate I is vertically welded with the bottom plate, a U-shaped through groove is formed in the vertical plate, and the U-shaped through groove is fixedly connected with a through hole in the ball head connecting plate through a bolt; one end of the ball head connecting plate, which is back to the supporting stand column, is provided with a ball hinge seat, and one end of the mounting seat is provided with a ball head which is arranged in the ball hinge seat; a plurality of fastening screws are arranged on the spherical hinge seat and used for fixing the spatial pose of the mounting seat; the other end of the mounting seat is provided with a frame matched with the surface of the convex lens and used for supporting the convex lens and fixedly connecting the convex lens through structural adhesive.

In the large-scale point focusing fresnel type solar light-gathering and heat-collecting system, the fresnel lenses are divided into a plurality of groups, each group forms an annular shape taking the center of the heat absorber as the center of a circle, and the diameters of the rings where the plurality of groups of fresnel lenses are located are different; the Fresnel lens is rectangular or circular in shape.

In the large point focusing fresnel type solar light-gathering and heat-collecting system, the fresnel lens is rectangular in shape.

In the large point focusing fresnel type solar light-gathering and heat-collecting system, the focal length of the fresnel lens is increased along with the reduction of the diameter of the ring where the fresnel lens is located.

Compared with the prior art, the beneficial effects of the utility model reside in that:

the utility model discloses simple structure, with low costs, bear rigidity good, the utility model discloses a fresnel lens combines or adopts fresnel lens and oval reflector combination with convex lens and plane mirror, has realized the application of small size fresnel lens on high-power level solar energy spotlight thermal-collecting system, the utility model discloses a biax that the antithetical couplet link mechanism that rigidity is excellent, low-cost is parallel realizes the spotlight ware is trailed, further reduces whole solar energy spotlight thermal-collecting system's manufacturing and installation cost.

Drawings

Fig. 1 is an axial view of the large-scale point focusing fresnel solar concentrating and heat collecting system of the present invention.

Fig. 2 is a side view of the connecting rod double-shaft tracking mechanism of the present invention.

Fig. 3 is an optical schematic diagram of embodiment 1 of the present invention.

Fig. 4 is an optical schematic diagram of embodiment 2 of the present invention.

Fig. 5 is a schematic view of the fixing and adjusting structure of the convex lens or the elliptical reflector.

FIG. 6 is a schematic view of a fixing and adjusting structure of the plane mirror.

In the figure: 1-a plane mirror I; 2-plane mirror II; 3-a convex lens; 4, Fresnel lens; 5-metal coil pipe; 6-heat absorption cavity; 7-secondary condenser; 8, a heat absorber; 9-elliptical reflector i; 10-elliptical reflector ii; 11-Fresnel lens II; 12-motor I; 13-screw mandrel I; 14-T-shaped guide groove I; 15-a spherical hinge sliding block I; 16-ball head connecting rod I; 17-a spherical hinge sliding block II; 18-ball head connecting rod II; 19-screw mandrel II; 20-motor II; 21-motor III; 22-screw mandrel iii; 23-a hinged slider i; 24-connecting rod I; 25-a turning block; 26-T-shaped guide groove II; 27-a support platform; 28-a condenser; 29-fixed frame; 30-a two-axis tracking platform; 31-a tracking controller; 32-hinged sliding block II; 33-adjusting seat I; 34-an adjusting seat II; 35-supporting the upright column; 36-T-shaped connecting plate i; 37-ball head connecting plate; 38-mounting seat; 39-T type link plate II; 40-mirror surface supporting seat; 41-set screw.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1, the present invention includes a condenser 28, a dual-axis tracking platform 30, a heat absorber 8, and a tracking controller 31; the condenser 28 comprises a fixed frame 29, a plurality of Fresnel lenses 4 and a reflecting unit; the Fresnel lens 4 and the heat absorber 8 are fixed on the fixed frame 29 and are arranged right opposite to the sun; a reflection unit is arranged below each Fresnel lens 4, and the reflection unit can reflect the sunlight focused by the Fresnel lens 4 to a heat absorber 8; the fixed frame 29 is fixedly arranged on a double-shaft tracking platform 30, the double-shaft tracking platform 30 is provided with a double-shaft tracker, the double-shaft tracker is connected with a tracking controller 31, and the tracking controller can control the fixed frame 29 to face the sun.

As shown in fig. 1 and 2, the dual-axis tracking platform 30 includes a dual-axis tracker and a supporting platform 27, the fixed frame 29 is mounted on the supporting platform 27, and the dual-axis tracker includes a driving motor, a T-shaped guide slot i 14 and a T-shaped guide slot ii 26; the driving motor comprises a motor I12, a motor II 20 and a motor III 21, the motor I12, the motor II 20 and the motor III 21 are respectively connected with the tracking controller 31, and the motor I12 and the motor II 20 are arranged at two ends of the T-shaped guide groove I14; the motor III 21 is arranged at one end of the T-shaped guide groove II 26; the T-shaped guide groove I14 and the T-shaped guide groove II 26 are horizontally arranged in parallel and oppositely. A screw rod III 22 is arranged in the T-shaped guide groove II 26, and the screw rod III 22 is fixedly connected with an output shaft of the motor III 21; the section of the screw rod III 22 at the midpoint is divided into two sections with equal length as an interface, the turning directions of threads on the two sections are opposite, the two sections of screw rods are respectively matched with the internal thread holes of the hinged sliding block I23 and the hinged sliding block II 32 through screw pairs, the hinged sliding block I23 and the hinged sliding block II 32 are respectively hinged with one end of the two connecting rods I24, the hinged sliding block I23 and the hinged sliding block II 32 are both in T-shaped structures, and the T-shaped structures are matched with the T-shaped guide groove II 26. The other ends of the two connecting rods I24 are hinged with a rotating block 25; the rotating block 25 is hinged with the bottom of the supporting platform 27, and the central lines of the two hinge pairs of the rotating block 25 are vertical.

A support seat is arranged in the middle of the T-shaped guide groove I14, the support seat divides the T-shaped guide groove I14 into two sections with equal length, a screw rod I13 and a screw rod II 19 are respectively installed in the two sections of the T-shaped guide groove I14, and the screw rod I13 and the screw rod II 19 are supported through the support seat in the T-shaped guide groove I14; the screw rod I13 and the screw rod II 19 are respectively matched with threaded holes of the spherical hinge sliding block I15 and the spherical hinge sliding block II 17 through screw pairs; the spherical hinge sliding block I15 and the spherical hinge sliding block II 17 are both of T-shaped structures, and the T-shaped structures are matched with the internal T-shaped grooves of the T-shaped guide groove I14; the spherical hinge sliding block I15 and the spherical hinge sliding block II 17 are respectively provided with a spherical hinge seat, and are respectively connected with a ball head connecting rod I16 and a ball head connecting rod II 18 through a spherical hinge pair; the other ends of the ball head connecting rod I16 and the ball head connecting rod II 18 are respectively provided with a ball head and are respectively connected with two ball hinge seats at the bottom of the supporting platform 27 in a ball hinge pair mode; the two spherical hinge seats and the rotating block 25 at the bottom of the supporting platform 27 are arranged in a triangular shape. As shown in fig. 1, the tracking controller 31 calculates the real-time spatial position of the sun, calculates the rotation angles of the motor i 12, the motor ii 20, and the motor iii 21, and sends corresponding control signals to control the motor i 12, the motor ii 20, and the motor iii 21 to rotate by corresponding angles, so as to align the central axis of the condenser 28 to the center of the sun, complete the dual-axis tracking function of the solar light-collecting system to the sun, and finally collect the sunlight inside the heat absorber 8.

Fig. 3 shows the structure of the transmitting unit in embodiment 1, where the reflecting unit includes a convex lens 3 and a plane mirror, the convex lens 3 is installed and fixed right below the center of its corresponding fresnel lens 4 through an adjusting base i 33, the image-side focal point of the fresnel lens 4 coincides with the object-side focal point of the convex lens 3, and the optical axes of the fresnel lens 4 and the convex lens 3 coincide; the plane mirror is fixed under the corresponding convex lens 3 through the adjusting seat II 34, and sunlight is reflected to the inside of the heat absorber 8 through the adjusting seat II 34. The Fresnel lenses 4 are divided into two groups which are symmetrically arranged on two sides of the heat absorber 8, and the plane mirrors are divided into two groups of plane mirrors I1 and two groups of plane mirrors II 2 with different inclination angles. The fresnel lens 4 may also be in the form of an annular array of multiple annular structures surrounding the heat absorber 8, and the focal length and geometric dimensions of the fresnel lens 4 may be different for each annular structure. The shape of the fresnel lens 4 can be rectangular or circular. Preferably, a rectangular geometry is used to make the arrangement more compact, reducing the gap between the fresnel lenses 4.

As shown in fig. 5, the adjusting seat i 33 includes a T-shaped connecting plate i 36, a ball head connecting plate 37, and a mounting seat 38, a U-shaped groove is formed in a bottom plate of the T-shaped connecting plate i 36, the U-shaped groove is fixedly connected with a through hole of a supporting column 35 of the fixing frame 29 through a bolt, and the height position of the T-shaped connecting plate i 36 is adjusted through the U-shaped groove; the vertical plate of the T-shaped connecting plate I36 is vertically welded with the bottom plate, a U-shaped through groove is formed in the vertical plate, and the U-shaped through groove is fixedly connected with a through hole in the ball head connecting plate 37 through a bolt; a ball hinged seat is arranged at one end of the ball head connecting plate 37, which is back to the supporting upright post 35, a ball head is arranged at one end of the mounting seat 38, and the ball head is arranged in the ball hinged seat; a plurality of set screws 41 are arranged on the spherical hinge seat and used for fixing the spatial pose of the mounting seat 38; the other end of the mounting base 38 is provided with a frame matched with the surface of the convex lens 3, and the frame is used for supporting the convex lens 3 and is fixedly connected with the convex lens 3 through structural adhesive. The installation and adjustment process of the convex lens 3 is as follows: the vertical direction is adjusted by adjusting the mounting position of the T-shaped connecting plate I36; then adjusting the position of the ball head connecting plate 37 in the horizontal direction; and finally, adjusting the spatial pose of the mounting seat 38 through a spherical hinge pair to realize that the object space focus of the convex lens 3 is superposed with the light converging focus of the Fresnel lens above the convex lens, and finally fixing the spatial pose of the mounting seat 38 through the jacking of a fastening screw 41.

As shown in fig. 6, the adjusting seat ii 34 includes a T-shaped link plate ii 39, a mirror surface supporting seat 40 and a set screw 41, the bottom end of the T-shaped link plate ii 39 is fixedly connected with the through hole of the supporting column 35 of the fixing frame 29 through a U-shaped groove by a bolt, and the height position of the T-shaped link plate ii 39 is adjusted through the U-shaped groove; the other end of the T-shaped connecting plate II 39 is provided with a spherical hinge seat, the mirror surface supporting seat 40 is L-shaped, one end of the mirror surface supporting seat 40 is provided with a ball head, the ball head is installed in the spherical hinge seat, and the spherical hinge seat is provided with a plurality of set screws 41 for fixing the spatial pose of the mirror surface supporting seat 40; the other end of the mirror surface supporting seat 40 is welded with a mirror surface mounting plate, and the mirror surface mounting plate is used for bonding the plane mirror.

The heat absorber 8 consists of a heat absorption cavity 6, a metal coil pipe 5, a secondary condenser 7 and a heat insulation layer, the metal coil pipe 5 is arranged in the heat absorption cavity 6 in a cylindrical cavity shape, and the secondary condenser 7 is arranged at the sunlight incidence end of the heat absorption cavity 6; the secondary condenser 7 is a specular reflection element with high reflectivity, and the reflection surface of the specular reflection element can be an inverted conical surface or a compound parabolic curved surface. The sunlight reflected by the plane mirror I1 and the plane mirror II 2 is projected to the inner surface of the secondary condenser 7, and then reaches the surface of the metal coil pipe 5 after being reflected for multiple times and is absorbed. The outer surface of the metal coil pipe 5 is plated with a high-temperature resistant coating with high solar energy absorption rate, and a fluid heat transfer working medium is communicated inside the metal coil pipe 5. Fig. 3 is the optical schematic diagram of the condenser 28 of embodiment 1, analyze as an example with a bundle of sunlight, the sunlight is shone from infinity and is come by fresnel lens 4 refraction, assemble to convex lens 3's object focus position just, then refract out for horizontal light beam by convex lens 3, this horizontal light beam continues to be arranged in the inside that transmits heat absorber 8 after the plane mirror reflection under convex lens 3, and absorb and form the high temperature by metal coil 5, and then heat the inside fluid working medium of metal coil 5, output high temperature fluid.

As shown in fig. 3, the distances between the fresnel lens 4, the convex lens 3 and the plane mirror in the vertical direction are adjustable. The height of the plane mirror I1 is lower than that of the plane mirror II 2, and the up-and-down position adjustment principle among elements is that sunlight reflected into the heat absorber 8 is not shielded.

Fig. 4 shows the structure of embodiment 2 of the reflecting unit, the reflecting unit adopts an elliptical reflecting mirror 10, the elliptical reflecting mirror 10 is installed and fixed under the fresnel lens 4 through an adjusting seat i 33, one focal point of the curved surface of the elliptical reflecting mirror 10 coincides with the image-side focal point of the fresnel lens 4, and the other focal point of the curved surface of the elliptical reflecting mirror 10 is located at the center of the light receiving window of the secondary condenser 7 at the front end of the heat absorber 8. The elliptical reflector is used for reflecting the solar energy collected by the Fresnel lens 4 to the inner surface of the secondary condenser 7, so that the solar energy is further transmitted to the surface of the metal coil inside the heat absorber 8. The Fresnel lens 4 is divided into a plurality of groups, each group forms an annular shape taking the center of the heat absorber 8 as the center of a circle, and the diameters of the annular shapes where the Fresnel lenses 4 are arranged are different. The focal length of the fresnel lens 4 increases as the diameter of the ring in which the fresnel lens 4 is located decreases.

Claims

1. A large-scale point focusing Fresnel type solar light-gathering and heat-collecting system is characterized in that: the system comprises a condenser, a double-shaft tracking platform, a heat absorber and a tracking controller; the condenser comprises a fixed frame, a plurality of Fresnel lenses and a reflecting unit; the Fresnel lens and the heat absorber are fixed on the fixed frame, and the Fresnel lens is arranged right opposite to the sun; a reflection unit is arranged below each Fresnel lens, and the reflection unit can reflect the sunlight focused by the Fresnel lens to the heat absorber; the fixed frame is fixedly installed on the double-shaft tracking platform, the double-shaft tracking platform is provided with a double-shaft tracker, the double-shaft tracker is connected with the tracking controller, and the tracking controller can control the fixed frame to face the sun.

2. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 1, which is characterized in that: the reflection unit comprises a convex lens and a plane mirror, the convex lens is fixedly arranged right below the center of the Fresnel lens through an adjusting seat I, the image space focus of the Fresnel lens is superposed with the object space focus of the convex lens, and the optical axes of the Fresnel lens and the convex lens are superposed; the plane mirror is fixed under the corresponding convex lens through the adjusting seat II, and sunlight is reflected to the inside of the heat absorber through the adjusting seat II.

3. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 1, which is characterized in that: the reflecting unit adopts an elliptical reflecting mirror, the elliptical reflecting mirror is fixedly arranged under the Fresnel lens through an adjusting seat I, one focus of the curved surface of the elliptical reflecting mirror is superposed with the image space focus of the Fresnel lens, and the other focus of the curved surface of the elliptical reflecting mirror is positioned at the center of a light receiving window of a secondary condenser at the front end of the heat absorber.

4. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 1, which is characterized in that: the double-shaft tracking platform comprises a double-shaft tracker and a supporting platform, the fixed rack is arranged on the supporting platform, and the double-shaft tracker comprises a driving motor, a T-shaped guide groove I and a T-shaped guide groove II; the driving motor comprises a motor I, a motor II and a motor III, the motor I, the motor II and the motor III are respectively connected with the tracking controller, and the motor I and the motor II are arranged at two ends of the T-shaped guide groove I; the motor III is arranged at one end of the T-shaped guide groove II; the T-shaped guide groove I and the T-shaped guide groove II are horizontally arranged in parallel and oppositely; a screw rod III is arranged in the T-shaped guide groove II and is fixedly connected with an output shaft of the motor III; the section of the screw rod III, where the midpoint is located, is taken as an interface and divided into two sections with equal length, the turning directions of threads on the two sections of screw rods are opposite, the two sections of screw rods are respectively matched with the internal thread holes of the hinged sliding block I and the hinged sliding block II through screw pairs, the hinged sliding block I and the hinged sliding block II are respectively hinged with one end of the two connecting rods I, the hinged sliding block I and the hinged sliding block II are both in T-shaped structures, and the T-shaped structures are matched with the T-shaped guide groove II; the other ends of the two connecting rods I are hinged with the rotating block; the rotating block is hinged with the bottom of the supporting platform, and the central lines of the two hinge pairs of the rotating block are vertical;

5. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 2, wherein: the adjusting seat II comprises a T-shaped connecting plate II, a mirror surface supporting seat and a set screw, the bottom end of the T-shaped connecting plate II is fixedly connected with a through hole of a supporting upright post of the fixed rack through a U-shaped groove through a bolt, and the height position of the T-shaped connecting plate II is adjusted through the U-shaped groove; the other end of the T-shaped connecting plate II is provided with a spherical hinge seat, the mirror surface supporting seat is L-shaped, one end of the mirror surface supporting seat is provided with a ball head, the ball head is installed in the spherical hinge seat, and the spherical hinge seat is provided with a plurality of set screws for fixing the spatial pose of the mirror surface supporting seat; the other end of the mirror surface supporting seat is welded with a mirror surface mounting plate.

6. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 2 or 3, which is characterized in that: the adjusting seat I comprises a T-shaped connecting plate I, a ball head connecting plate and a mounting seat, a U-shaped groove is formed in a bottom plate of the T-shaped connecting plate I, the U-shaped groove is fixedly connected with a through hole of a supporting upright post of the fixed rack through a bolt, and the height position of the T-shaped connecting plate I is adjusted through the U-shaped groove; a vertical plate of the T-shaped connecting plate I is vertically welded with the bottom plate, a U-shaped through groove is formed in the vertical plate, and the U-shaped through groove is fixedly connected with a through hole in the ball head connecting plate through a bolt; one end of the ball head connecting plate, which is back to the supporting stand column, is provided with a ball hinge seat, and one end of the mounting seat is provided with a ball head which is arranged in the ball hinge seat; a plurality of fastening screws are arranged on the spherical hinge seat and used for fixing the spatial pose of the mounting seat; the other end of the mounting seat is provided with a frame matched with the surface of the convex lens and used for supporting the convex lens and fixedly connecting the convex lens through structural adhesive.

7. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 3, wherein: the Fresnel lenses are divided into a plurality of groups, each group forms an annular shape taking the center of the heat absorber as the center of a circle, and the diameters of the annular shapes where the plurality of groups of Fresnel lenses are positioned are different; the Fresnel lens is rectangular or circular in shape.

8. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 7, wherein: the fresnel lens has a rectangular outer shape.

9. The large point focusing Fresnel type solar energy light and heat collecting system according to claim 7, wherein: the focal length of the fresnel lens increases as the diameter of the annulus in which the fresnel lens is located decreases.