CN115900107A

CN115900107A - Heliostat and method for reducing shielding loss in mirror field of tower type photo-thermal power station

Info

Publication number: CN115900107A
Application number: CN202211308509.3A
Authority: CN
Inventors: 王东祥; 宋秀鹏
Original assignee: SEPCO3 Electric Power Construction Co Ltd
Current assignee: SEPCO3 Electric Power Construction Co Ltd
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2023-04-04

Abstract

The invention discloses a heliostat and a method for reducing shielding loss in a mirror field of a tower type photo-thermal power station, wherein the heliostat comprises a reflector, a support and a driver, the reflector comprises a main reflector and auxiliary reflectors positioned on two sides of the main reflector, the auxiliary reflectors are connected with the main reflector through hinges, the back of the main reflector is provided with a truss, and the truss is connected with the support through the driver; install electric telescopic handle's stiff end on the truss, the back of assisting the speculum is connected to electric telescopic handle's output, and the supplementary speculum back is fixed with photosensitive equipment, and photosensitive equipment converts light signal into the control system that the signal of telecommunication conveyed mirror field. According to the method disclosed by the invention, when the solar altitude is very low, the heliostat can be adjusted according to the shielding condition, so that the shielding loss is reduced, the whole optical efficiency of a heliostat field is improved, and when no shielding occurs, the heliostat is restored to the original state, and the daylighting area is effectively increased.

Description

Heliostat and method for reducing shielding loss in mirror field of tower type photo-thermal power station

Technical Field

The invention relates to the technical field of tower type photo-thermal power stations, in particular to a heliostat and a method for reducing shielding loss in a mirror field of a tower type photo-thermal power station.

Background

Solar energy is one kind of clean energy, and is widely popularized and applied due to the characteristics of large energy, sustainability, no pollution and the like. Solar power generation technologies can be divided into photovoltaic and photothermal. The photo-thermal power generation comprises a tower type, a groove type, a disc type and a linear Fresnel type, wherein the tower type solar photo-thermal power generation technology is concerned about due to the advantages of short heat transfer path, low heat loss, high heat collection efficiency and the like. The heliostat is an important solar energy collecting unit in a tower type solar photothermal power station system, and can reflect solar energy to a heat absorber of a heat absorption tower, so that the solar energy is collected.

In recent years, solar photo-thermal power generation technology is greatly developed, and compared with traditional photovoltaic power generation, the solar photo-thermal power generation device has the advantages of flexible energy storage and adjustable power generation. Among the solar photo-thermal technologies, the tower-type solar photo-thermal power generation technology is gradually favored by people due to high heat collection efficiency. In a solar photothermal power station, a mirror field is a solar energy collecting device, and as shown in fig. 1, in a photothermal power station, a heliostat 1 tracks solar rays in real time and reflects the solar rays to a heat absorber 2 of a heat absorbing tower. In this process, because the change of sun position, front-row heliostat 1 can take place to shelter from to the light that back-row heliostat 1 reflects to make the reflected solar light of rear heliostat can't accurately reflect to the heat absorber of heat absorption tower, cause and shelter from the loss, thereby influence the optical efficiency in mirror field.

The optical efficiency of the mirror field is an important evaluation index of the performance of the mirror field, the optical efficiency refers to the utilization rate of the whole photo-thermal mirror field to solar energy, and the improvement of the optical efficiency is a key factor for improving the comprehensive efficiency of the photo-thermal power station system. The heliostat commonly used at present is rectangular, and some heliostats are directly set into different shapes (circular, pentagonal and hexagonal) in design and used for reducing the shielding loss of a heliostat field, but the daylighting area of the heliostat field can be reduced by the method when no shielding loss exists among the heliostats.

Disclosure of Invention

In order to solve the technical problems, the invention provides a heliostat and a method for reducing shielding loss in a mirror field of a tower type photo-thermal power station.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a heliostat for reducing shielding loss in a mirror field of a tower type photo-thermal power station comprises a reflector, a support and a driver, wherein the reflector comprises a main reflector and auxiliary reflectors positioned on two sides of the main reflector; install electric telescopic handle's stiff end on the truss, electric telescopic handle's output is connected the back of assisting the speculum, it is fixed with photosensitive equipment to assist the speculum back, photosensitive equipment converts light signal into the control system that the signal of telecommunication conveyed mirror field.

In the above scheme, the photosensitive device is a photodiode.

In the above scheme, two sides of the main reflector are respectively connected with 3 auxiliary reflectors.

In the scheme, 4-6 photosensitive devices are fixed on the back of each auxiliary reflecting mirror.

In the scheme, the two ends of the electric telescopic rod are respectively connected with the truss and the auxiliary reflector through the connecting buckles.

In the scheme, the area of all the auxiliary reflectors accounts for 35-45% of the area of the whole reflector.

In the above scheme, the truss is hollow, and the wires of the photosensitive device and the electric telescopic rod penetrate through the interior of the truss and are connected with the power supply device of the mirror field through the driver.

A method for reducing shielding loss in a mirror field of a tower type photo-thermal power station adopts the heliostat, and comprises the following steps:

when the front heliostat does not shield the rear heliostat, the electric telescopic rod of the front heliostat is in an extension state, the main reflector and the auxiliary reflector of the front heliostat are positioned on the same plane, and the control system of the heliostat field controls the driver of the front heliostat to carry out normal sun tracking operation;

when the place ahead heliostat takes place to shelter from to the rear heliostat, the light of rear heliostat reflection can shine the supplementary speculum back of place ahead heliostat to received by the sensitization equipment at this supplementary speculum back, sensitization equipment converts light signal into the control system of signal of telecommunication transfer mirror field, the control system in mirror field gives an instruction to the place ahead heliostat, the electric telescopic handle who is connected with this supplementary speculum shrink, with this supplementary speculum pull back main reflection mirror back, thereby reduce sheltering from to the rear heliostat.

In a further technical scheme, the auxiliary reflector is pulled back to the back of the main reflector for 1 hour and then restored to the original state in the northern hemisphere between 3 months and 11 months, and the auxiliary reflector is pulled back to the back of the main reflector for 1.5 hours and then restored to the original state in the next 2 months between 12 months.

In a further technical scheme, when a strong wind condition occurs at the location of the photothermal power station, the control system of the mirror field gives an instruction to the heliostat, and all the auxiliary reflectors are pulled back to the back surfaces of the main reflectors.

Through the technical scheme, the heliostat and the method for reducing shielding loss in the mirror field of the tower type photo-thermal power station have the following beneficial effects:

(1) The heliostat is divided into a main reflector and auxiliary reflectors positioned on two sides, the auxiliary reflectors can be adjusted according to the position of the sun, and the shielding of the rear heliostat is reduced, so that the shielding loss is reduced, and the overall optical efficiency of a mirror field is improved.

(2) When the ground wind of the photo-thermal power station is enlarged, the auxiliary reflecting mirror of the heliostat executes a retracting instruction, so that the contact surface of wind is reduced, and the wind resistance of the heliostat is improved.

(4) The heliostat can be folded, is convenient to transport, and is beneficial to reducing the transport cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a schematic view of the operation of a heliostat;

FIG. 2 is a schematic front view of a heliostat of the invention in the absence of an obscuration condition;

FIG. 3 is a schematic rear view of a heliostat of the invention in the absence of an obscuration condition;

FIG. 4 is a schematic front view of a heliostat of the invention in the presence of an obscuration condition;

FIG. 5 is a schematic rear view of a heliostat of the invention in the presence of occlusions.

In the figure, 1, heliostat; 2. a heat sink; 3. a mirror; 4. a support; 5. a driver; 6. a main mirror; 7. an auxiliary reflector; 8. a hinge; 9. a truss; 10. an electric telescopic rod; 11. a photosensitive device; 12. a connecting buckle.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The invention provides a heliostat 1 for reducing shielding loss in a mirror field of a tower type photo-thermal power station, which comprises a reflecting mirror 3, a bracket 4 and a driver 5, wherein the reflecting mirror 3 is used for accurately reflecting solar rays to a heat absorber 2 of a heat absorption tower. The actuator 5 is used for controlling the reflector 3 to perform rotation movement in two directions of pitching and azimuth after receiving the control system command of the mirror field, thereby performing accurate sun tracking. The support 4 is located below the driver 5 and is the supporting and fixing means of the whole heliostat 1.

As shown in fig. 2 and 3, the mirror 3 includes a main mirror 6 and sub-mirrors 7 provided on both sides of the main mirror 6, and the sub-mirrors 7 and the main mirror 6 are connected by hinges 8 so as to be flipped back and forth. In this embodiment, 3 sub mirrors 7 are connected to both sides of the main mirror 6, respectively. The main reflector 6 and the auxiliary reflector 7 are both rectangular, the whole area of the reflector of the invention is the same as that of the existing reflector, and the existing reflector is only divided into different working areas. In the present invention, the area of all the sub-mirrors 7 occupies 30 to 45% of the area of the entire mirror 1.

6 back mounted of primary mirror has truss 9, and truss 9 passes through driver 5 linking bridge 4, and the control system in mirror field drives truss 9 through driver 5 and rotates to it is rotatory to drive primary mirror 6, realizes pursuing the sun motion. The fixed end of the electric telescopic rod 10 is arranged on the truss 9 through a connecting buckle 12, and the output end of the electric telescopic rod 10 is connected to the back center position of the auxiliary reflector 7 through the connecting buckle 12. When the electric telescopic rod 10 outputs, the auxiliary reflecting mirror 7 and the main reflecting mirror 6 are positioned on the same plane, and the reflection work of sunlight is carried out together; when the telescopic power rod 10 is retracted, the secondary mirror 7 is pulled back to the back of the primary mirror 6, as shown in fig. 4 and 5. The electric telescopic rod 10 can adopt a mode that a motor drives a screw rod to rotate, or a hydraulic cylinder or a pneumatic cylinder and the like.

A photosensitive device 11 is fixed to the back of the secondary mirror 7. The photosensitive device 11 is mainly used to detect whether the front heliostat 1 will block the rear heliostat 1. Typically, the locations where the front heliostat 1 obscures are primarily at the edge locations of the mirror 1, and the zones of the secondary mirror 7 divided by the present invention may substantially cover these locations. If occlusion occurs, the light reflected by the rear heliostat 1 strikes the back of the secondary mirror 7 of the front heliostat 1 and is received by the photosensitive device 11.

The photodiode has the characteristics of small volume, light weight, long service life, high sensitivity, fast response time and the like, so in the embodiment, the photodiode is selected as the photosensitive device 11. The photosensitive diode can quickly react to light, convert an optical signal into an electric signal and transmit the electric signal to a control system of the mirror field. 4-6 photodiodes are fixedly distributed at different positions on the back surface of each auxiliary reflector 7.

The interior of the truss 9 is hollow, and the wires of the photosensitive device 11 and the electric telescopic rod 10 penetrate through the interior of the truss 9 and are connected with a power supply device of a mirror field through the driver 5, so that power can be supplied to the photosensitive device 11 and the electric telescopic rod 10.

A method for reducing shielding loss in a mirror field of a tower type photo-thermal power station adopts the heliostat 1 and comprises the following steps:

when the front heliostat 1 does not shield the rear heliostat 1, the electric telescopic rod 10 of the front heliostat 1 is in an extended state, as shown in fig. 2 and 3, the main reflector 6 and the auxiliary reflector 7 of the front heliostat 1 are located on the same plane, and the control system of the mirror field controls the driver 5 of the front heliostat 1 to perform normal sun-chasing operation.

When the front heliostat 1 shields the rear heliostat 1, light reflected by the rear heliostat 1 can shine on the back of the auxiliary reflector 7 of the front heliostat 1, so that the light is received by the photosensitive device 11 on the back of the auxiliary reflector 7, the photosensitive device 11 converts a light signal into an electric signal and transmits the electric signal to the control system of the heliostat field, the control system of the heliostat field sends an instruction to the front heliostat 1, the electric telescopic rod 10 connected with the auxiliary reflector 7 contracts, and as shown in fig. 4 and 5, the auxiliary reflector 7 is pulled back to the back of the main reflector 6, so that shielding of the rear heliostat 1 is reduced.

The time for performing the rehabilitation action needs to be determined according to different seasons. Shading typically occurs when the sun is low in altitude, i.e., morning and evening. The solar altitude changes significantly within 2 hours. In order to maximize the solar energy received by the mirror field, the solar energy is determined according to the position of the sun in different seasons. In the northern hemisphere, between 3 and 11 months, the auxiliary reflector 7 is pulled back to the back of the main reflector 6 for 1 hour and then returns to the original state, and between 12 months and 2 months in the next year, the auxiliary reflector 7 is pulled back to the back of the main reflector 6 for 1.5 hours and then returns to the original state.

When the strong wind condition appears in the light and heat power plant location, the control system in mirror field can give heliostat 1 and send out the instruction, all the supplementary speculum 7 all pull back to the main reflector 6 back to reduce the wind pressure that heliostat 1 received, furthest guarantees heliostat 1's safety. And when heliostat 1 transports, supplementary speculum 7 also can fold to save space, reduce the cost of transportation.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A heliostat for reducing shielding loss in a mirror field of a tower type photo-thermal power station comprises a reflector, a support and a driver, and is characterized in that the reflector comprises a main reflector and auxiliary reflectors positioned on two sides of the main reflector, the auxiliary reflectors are connected with the main reflector through hinges, a truss is mounted on the back of the main reflector, and the truss is connected with the support through the driver; install electric telescopic handle's stiff end on the truss, electric telescopic handle's output is connected the back of assisting the speculum, it is fixed with photosensitive equipment to assist the speculum back, photosensitive equipment converts light signal into the control system that the signal of telecommunication conveyed the mirror field.

2. The heliostat of claim 1, wherein the photosensitive device is a photodiode.

3. The heliostat of claim 1 wherein the primary reflector is flanked by 3 secondary reflectors in the field of mirrors.

4. A heliostat for reducing shadowing losses in a mirror field of a tower photo-thermal power station according to claim 1, 2 or 3 wherein 4-6 photosensitive devices are fixed to the back of each secondary mirror.

5. The heliostat for reducing shielding loss in a mirror field of a tower-type photothermal power station according to claim 1, wherein two ends of the electric telescopic rod are respectively connected with the truss and the auxiliary reflector through connecting buckles.

6. The heliostat of claim 1 wherein the truss is hollow and wires of the photosensitive device and the telescopic electrical rod pass through the truss interior and are connected to a power supply of the mirror field via a drive.

7. The heliostat of claim 3 wherein all secondary mirrors occupy 35-45% of the total mirror area.

8. A method of reducing shadowing losses in a mirror field of a tower-type photothermal power station, using the heliostat of claim 1, comprising the process of:

when the place ahead heliostat takes place to shelter from to the rear heliostat, the light that the rear heliostat was reflected can shine the supplementary speculum back of place ahead heliostat to received by the sensitization equipment at this supplementary speculum back, sensitization equipment converts light signal into the control system that the signal of telecommunication conveyed mirror field, the control system in mirror field gives out the instruction to the place ahead heliostat, the electric telescopic handle shrink of being connected with this supplementary speculum, with this supplementary speculum pull back to the main mirror back, thereby reduce sheltering from to the rear heliostat.

9. The method of claim 8 wherein the secondary reflector is pulled back to the back of the primary reflector for 1 hour before returning to its original shape during the northern hemisphere between 3 and 11 months, and wherein the secondary reflector is pulled back to the back of the primary reflector for 1.5 hours before returning to its original shape during the next 2 months from 12 months to the next year.

10. The method of claim 8, wherein the control system of the mirror farm instructs the heliostat to pull all of the secondary mirrors back to the back of the primary mirror in the event of high winds at the site of the photothermal power plant.