CN108981200B

CN108981200B - Condensing unit based on fresnel lens

Info

Publication number: CN108981200B
Application number: CN201810907764.7A
Authority: CN
Inventors: 张铈岱; 何海双; 庞勇军
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2018-08-10
Filing date: 2018-08-10
Publication date: 2020-03-17
Anticipated expiration: 2038-08-10
Also published as: CN108981200A

Abstract

The invention discloses a Fresnel lens-based light condensing device which comprises a Fresnel lens, a photoelectric sensor, a cooling fin, a cooling pipe, a circulating pump, a water tank, a motor, a transmission device, a control chip and the like. The whole device is fixed on a foundation, a specific angle is formed between the device and a horizontal plane according to the latitude of each region, only the Fresnel lens array performs horizontal and longitudinal two-axis linkage for sun tracking at a specific speed, and the sunlight is always kept focused on a single or a plurality of light-gathering target objects. The heat exchange device at the bottom can transfer the heat generated by the condensation of the target object to the cold fluid. The device is more flexible to the requirement of basis, reduces transmission and drive arrangement's load by a wide margin, can promote effectively and follow the sun tracking precision, and the cost also can be cheaper, and is all more convenient to construction, calibration, later maintenance.

Description

Condensing unit based on fresnel lens

Technical Field

The invention relates to a light condensing device, in particular to a light condensing device based on a Fresnel lens, and belongs to the technical field of light condensing solar energy.

Background

The solar light condensing technology is a technology of condensing light energy by using an optical element to generate light energy with high light intensity. At present, the solar energy condensation technology is mainly realized by adopting reflection and refraction modes, such as tower type condensation, disc type Stirling condensation power generation, C7 Trcaker of SUNPOWER company in the United states and the like, which all adopt the reflection type solar energy condensation technology; the GaAs (gallium arsenide) high-power light-gathering module of the sun core photovoltaic technology limited company adopts a refraction type solar light-gathering technology. The technology is commercially applied to a certain extent, and shows that the solar light condensation technology can improve the light intensity on unit area and increase the utilization rate of sunlight resources, and can be applied to the field of photovoltaic power generation and the field of photo-thermal.

At present, a refraction method is adopted, and most of the solar energy condensing systems which are mature to use Fresnel lenses are mainly divided into full-glass Fresnel lenses, silica gel-glass (silicon on glass) type Fresnel lenses and PMMA (polymethyl methacrylate) Fresnel lenses. The common approach is to assemble the fresnel lens with the photovoltaic cell, the housing, the heat dissipation system, etc. into an assembly, mount it into an array and perform a uniform sun tracking.

However, the light-gathering mode has the disadvantages that the stress of the bracket is increased undoubtedly due to the sun tracking of the whole system, and the stability of the bracket is reduced; the static load and the impact load of the transmission and driving device are large, so that the inertia of a transmission system is increased, a tracking error is generated, and the light condensation effect is influenced. Because the assemblies are integrally installed, the requirement on the machining precision of the Fresnel lens is high, the requirement on the assembly precision of the assemblies is also high, the fine-adjustable space of the solar light-gathering equipment in the construction process of a solar power station is small, the high requirement on the precision control in the construction process is high, and the fault-tolerant space and the maintainability of the whole equipment are directly reduced.

Disclosure of Invention

The invention aims to solve the technical problem of providing a Fresnel lens-based light condensing device which has the characteristics of high sun tracking precision, simple structure, stable support and small motion inertia.

In order to achieve the above purpose, the solution of the invention is:

a condensation device based on a Fresnel lens comprises the Fresnel lens, a photoelectric sensor, a cooling fin, a cooling pipe, a circulating pump, a water tank, a motor, a transmission device, a control chip and the like. The whole device is fixed on a foundation, forms a specific angle with a horizontal plane according to the latitude of each region, and only uses the Fresnel lens to perform horizontal and longitudinal two-axis linkage for sun tracking, so that the sunlight is always focused on a single or a plurality of light-gathering target objects. The heat exchange device at the bottom can transfer the heat generated by the condensation of the target object to the cold fluid.

Furthermore, the whole device is fixed on a base, only the Fresnel lens can do horizontal and longitudinal two-axis linkage for sun tracking, and the converged light spots are uniformly focused on a light-gathering target object. The relationship between the speed of longitudinal movement of the fresnel lens and the angular speed of angular variation of the solar altitude conforms to the following equation:

in the formula, v₁The longitudinal moving speed of the Fresnel lens; f is the focal length of the Fresnel lens; omega₁Is the angular velocity of the change in the solar altitude; t is time; delta₁Is a correction parameter.

The relationship between the lateral movement velocity of the fresnel lens and the angular velocity of the solar azimuthal variation conforms to the following equation:

in the formula, v₂Is the lateral movement speed of the Fresnel lens; f is the focal length of the Fresnel lens; omega₂Is the angular velocity of the change in the azimuth of the sun; t is time; delta₂Is a correction parameter.

The control chip makes certain correction calculation on meteorological conditions, tracking errors, transmission errors and the like according to the written program; the control chip can also carry out correction calculation according to the light spot boundary signals measured by the photoelectric sensor, and the calculation result is the correction parameters of the longitudinal and transverse moving speeds of the Fresnel lens. The control chip also controls the motor and the motor driver to move.

Further, the fresnel lenses may be regularly arranged in an X row X Y column planar array. The condensing targets are arranged in an X row X Y column planar array corresponding to the fresnel lenses. Wherein X and Y are both natural numbers greater than or equal to 1.

Furthermore, the fresnel lens is parallel to the light-gathering target or parallel to the cross section of the axis of the target, and the light-gathering target can be a planar light-gathering target or a cylindrical light-gathering target.

Furthermore, the included angle between the Fresnel lens and the horizontal plane is equal to the latitude of the installation area.

Further, the heat exchanger can transfer heat generated by condensing the target to the cold fluid.

After the technical measures are adopted, compared with other light-gathering structures, the light-gathering structure has the following advantages: the sun tracking can be realized only by the transverse and longitudinal two-axis linkage of the Fresnel lens, so that the mechanical structure which needs integral sun tracking in the past is omitted, the stress of the support is reduced, and the stability of the support is improved. And because the moving part has small mass and is light and thin, the static load and the impact load of the transmission and driving device are greatly reduced, and the inertia of the transmission part and the power of the driving part are correspondingly reduced. The sun tracking precision can be effectively improved, and compared with the conventional light condensing device, the sun tracking device is lower in cost.

In addition, because the whole device is fixed on the foundation, the relative motion relation is not existed. The requirement on the foundation is more flexible, and the construction, calibration and later maintenance are more convenient. Aiming at the occasion needing good heat dissipation, compared with the prior light gathering equipment, the heat exchange device in the equipment can be directly fixed with the foundation without using a cold fluid switching hose with bending requirement because the heat exchange device does not need to be tracked together with the assembly, thereby avoiding the defect that the hose has short service life due to long-term bending. The installation is more convenient and reliable, and the advantage is more obvious.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Fig. 1 is a schematic structural diagram of a first embodiment of a light condensing device based on a fresnel lens according to the present invention;

FIG. 1A is a schematic view of the Y-Z plane of FIG. 1 illustrating the path of incident sunlight from the linear Fresnel lens;

FIG. 1B is a schematic view of the Y-Z plane of FIG. 1 illustrating the path of incident sunlight from the circular Fresnel lens;

FIG. 1C is a schematic view of the path of sunlight incident in the X-Z plane of FIG. 1;

FIG. 2 is a schematic view of the light path of the incident sunlight after the Fresnel lens moves a certain distance along the longitudinal direction in the Fresnel lens-based light focusing device of the present invention;

FIG. 3 is a schematic structural diagram of a second embodiment of a Fresnel lens-based light condensing device according to the present invention;

FIG. 4 is a schematic view of the light focusing assembly of FIGS. 1, 2 and 3 using a circular Fresnel lens;

fig. 5 is a schematic diagram of the light condensing assembly of fig. 1, 2 and 3 using a linear fresnel lens.

In the figure:

fresnel lens 1

Circular Fresnel lens 101 Linear Fresnel lens 102

Screw thread 103

Cooling fin 2 cooling tube 3

Photoelectric sensor 4 circulating pump 5

Water tank 6

Light-condensing object 7

Planar light-condensing object 701 cylindrical light-condensing object 702

Detailed Description

In order to further explain the technical scheme of the invention, the invention is explained in detail by the following specific examples, which do not limit the invention in any way.

When sunlight rays enter, as shown in fig. 1, fig. 1A, fig. 1B and fig. 1C, the entire device of the light condensing device based on the fresnel lens 1 according to the present invention is fixed on a base, and the fresnel lens 1 controls the motion of each axis motor and the motor driver thereof according to a control chip programmed in advance, so that the fresnel lens 1 can perform horizontal and vertical two-axis linkage for tracking sun, thereby focusing sunlight on a single or a plurality of light condensing target objects 7. For the occasion that needs good heat dissipation, still be provided with fin 2, the cooling tube 3 of bottom can transmit the heat of spotlight object 7 to the cold fluid, through the circulating pump 5 with the continuous circulation of the liquid in the water tank 6 in order to reach the radiating purpose. As shown in fig. 1C and 3, the light-condensing object may be a planar light-condensing object 701 or a cylindrical light-condensing object 702. The control chip makes certain correction calculation for meteorological conditions, tracking errors, transmission errors and the like according to the written program; the control chip also carries out correction calculation according to the light spot boundary signals measured by the photoelectric sensor 4, and the calculation result is the correction parameters of the longitudinal and transverse movement speeds of the Fresnel lens.

As the sun moves, as shown in fig. 2, the fresnel lens 1 also moves a corresponding distance to keep the light-gathering spot uniformly focused on the light-gathering target 7, as shown in fig. 4 and 5, the fresnel lens used for light gathering may be a circular fresnel lens 101 or a linear fresnel lens 102, each thread 103 of the fresnel lens 1 faces the light-gathering target 7, and the size of the thread 103 is determined according to the focal length and the size of the light spot.

The relationship between the speed of longitudinal movement of the fresnel lens and the angular speed of angular variation of the solar altitude conforms to the following equation:

Preferably, when circular fresnel lenses 101 are used, circular light spots are generated after light condensation, and each circular fresnel lens 101 corresponds to one light condensation target object 7, as shown in fig. 4, the circular fresnel lenses 101 are arranged in a 2-row × 2-column planar array, and four light spots are generated, so that four circular fresnel lenses 101 and four light condensation target objects 7 are required. Of course, in a specific application, the circular fresnel lenses 101 may be arranged in an X row X Y column planar array, and X and Y are selected to be natural numbers greater than or equal to 1.

Preferably, when the linear fresnel lens 102 is used, a rectangular light spot is generated after light condensation, as shown in fig. 5, and the number of the linear fresnel lens 102 and the light condensation object 7 does not have to be one-to-one, and a cylindrical light condensation object 702 as shown in fig. 3 may be used. In fig. 5, the linear fresnel lenses 102 arranged in a 2 row by 2 column planar array will produce two rectangular spots, so that a single or light-focusing target 7 need only be in a spot. Of course, in a specific application, the linear fresnel lenses 102 may be arranged in an X row X Y column planar array, and X and Y are selected to be natural numbers greater than or equal to 1.

The above embodiments and drawings do not limit the form and style of the present invention, and any suitable changes or modifications thereof by those skilled in the art should be considered as not departing from the scope of the present invention.

Claims

1. The utility model provides a beam condensing unit based on fresnel lens, includes fresnel lens, photoelectric sensor, fin, cooling tube, circulating pump, water tank, motor, transmission, control chip, its characterized in that: the Fresnel lens is arranged above the light-gathering target object through a support; the cooling fin is arranged below the light-gathering target object and the photoelectric sensor, the cooling pipe at the bottom of the cooling fin can transfer the heat of the light-gathering target object to the cold fluid, and the circulating pump is connected between the water tank and the cooling pipe; the control chip controls the motion of the motor and the transmission device; the integral device is fixed on a foundation, forms a specific angle with a horizontal plane according to the latitude of each region, and only makes horizontal and longitudinal two-axis linkage through the Fresnel lens to always keep sunlight focused on a light-gathering target object; the relation between the longitudinal movement speed of the Fresnel lens and the angular speed of the change of the solar altitude accords with the following formula, and on the basis, correction parameters are calculated and compensated by the control chip according to meteorological conditions, tracking errors and transmission errors:

2. A fresnel lens-based light concentrating device according to claim 1, wherein: the fresnel lens is parallel to the condensing target.

3. A fresnel lens-based light concentrating device according to claim 1, wherein: the included angle between the Fresnel lens and the horizontal plane is equal to the latitude of the installation area.

4. A fresnel lens-based light concentrating device according to claim 1, wherein: the Fresnel lenses are regularly arranged into an X-row X-Y-column plane array, and the condensation target objects and the Fresnel lenses are correspondingly arranged into an X-row X-Y-column plane array; wherein X and Y are both natural numbers greater than or equal to 1.

5. A fresnel lens-based light concentrating device according to claim 1, wherein: the heat radiating fins transmit heat generated by condensing the light condensing object to the cold fluid, and the heat energy is stored in the water tank through the circulating pump.

6. A fresnel lens-based light concentrating device according to claim 1, wherein: the relation between the transverse movement speed of the Fresnel lens and the angular speed of the change of the solar azimuth angle accords with the following formula, and on the basis, correction parameters are calculated and compensated by the control chip according to meteorological conditions, tracking errors and transmission errors: