CN-115438469-B - Method for calculating shadow efficiency of absorber tower to mirror field in tower type photo-thermal power station

CN115438469BCN 115438469 BCN115438469 BCN 115438469BCN-115438469-B

Abstract

The invention relates to the technical field of tower type photo-thermal stations, in particular to a method for calculating the shadow efficiency of a heat absorption tower in a tower type photo-thermal station on a lens field. The method comprises the steps of obtaining the position and vertex coordinates of heliostats, calculating target points corresponding to each heliostat, simultaneously calculating normal vectors of each heliostat and normalizing, calculating symmetrical positions of the sun relative to a heat absorption tower, calculating included angles between the normal vectors and the heliostats to the sun to obtain reflected light rays corresponding to each heliostat at the moment, abstracting the heat absorption tower into a quadrilateral plane and solving, calculating shielding and marking of the back reflections of the heat absorption tower on the heliostats, and calculating shadow efficiency of the heat absorption tower on the heliostats. The design of the invention is based on the design of the inverse shadow method, so that the tower type solar thermal power generation can be more accurately designed, the shielding efficiency of the heat absorption tower to the heliostat is calculated by utilizing the thought of the inverse shadow, the understanding is easier, and meanwhile, the calculation method based on the spatial resolution geometric thought has wider application range.

Inventors

LI TAO
WANG DONGXIANG
Wang renbao
SONG XIUPENG

Assignees

山东电力建设第三工程有限公司

Dates

Publication Date: 20260505
Application Date: 20220815

Claims (5)

1. A method for calculating the shadow efficiency of a heat absorption tower to a lens field in a tower type photo-thermal power station is characterized by comprising the following steps: S1, geometrically arranging heliostat fields to obtain heliostat position coordinates and vertex coordinates; S2, calculating a target point corresponding to each heliostat according to the tower height and shape of the heat absorption tower and a nearby principle or other principles, obtaining included angles between the heliostat and the sun and between the heliostat and the target point by using a reflection theorem according to the position of the sun, and simultaneously calculating a normal vector of each heliostat and normalizing the normal vector into a unit vector; s3, calculating the symmetrical position of the sun relative to the heat absorption tower according to the position of the sun; S4, according to the new sun position vector and the normal vector of each heliostat, calculating the included angle between the normal vector and the heliostat to the sun, and obtaining the reflected light corresponding to each heliostat at the moment by using the reflection theorem, wherein the specific algorithm of the step S4 comprises the following steps: According to the sun position vector Normal vector of each heliostat And (3) calculating the normal vector and the included angle between the heliostat and the sun: ; Wherein, the Obtaining the reflected light corresponding to each heliostat at the moment by using the reflection theorem: ; the method is characterized by comprising the following steps: ; Respectively establishing the passing points according to the related knowledge of the space analytic geometry To Straight line equation for direction vector: ; Wherein the method comprises the steps of XYZ coordinates for the kth vertex of the ith heliostat; S5, abstracting the heat absorption tower into a quadrilateral plane, obtaining four vertexes of the plane according to the tower height and the position of the heat absorption tower, substituting coordinates of the four vertexes into a plane equation, and finally obtaining a plane surrounded by the four vertexes, wherein the concrete algorithm of the step S5 comprises the following steps: Abstracting the heat absorption tower into a quadrilateral plane, and obtaining four vertexes of the plane according to the tower height and the position of the heat absorption tower, wherein the four vertexes are respectively as follows: ; ; ; ; Wherein the method comprises the steps of Is the solar azimuth angle, L is the upper column bottom diameter length, T is the column height, and then the coordinates of the four vertices are substituted into the plane equation: ; The plane surrounded by the four vertexes is obtained as follows: ; S6, calculating the shielding of the heat absorption tower back shadow on the heliostat, marking the shielded heliostat, and further calculating the shadow efficiency of the heat absorption tower on the heliostat, wherein in the step S6, the specific method for calculating the shielding of the heat absorption tower back shadow on the heliostat comprises the following steps: for heliostat i, calculate As a direction vector, cross its vertex Whether the linear equation of (2) can pass through the plane of the absorber, i.e.: ; Calculating and judging whether the solution obtained by the equation set is in the value range of the plane of the heat absorption tower, if the obtained solution value range is in the value range of the plane of the heat absorption tower, indicating that reflected light rays pass through the plane of the heat absorption tower, namely the heat absorption tower has a shadow effect on heliostats; all heliostats are calculated according to the same method, and as long as the reflected light rays with certain vertexes found in the heliostats pass through the plane of the heat absorption tower, the heat absorption tower has a shadow effect on the heliostats.
2. The method for calculating the shadow efficiency of the absorber tower to the mirror field in the tower-type photo-thermal power station according to claim 1, wherein in the step S1, the geometrical arrangement of the heliostat field is performed, and the specific method for obtaining the heliostat position coordinates and the vertex coordinates is as follows: According to the field conditions of the tower type solar photo-thermal power station, the design parameters, the design efficacy and the like of heliostats, arranging the mirror fields to obtain the serial number of each heliostat Let the central position coordinate be Vertex coordinates of each heliostat ; Wherein the method comprises the steps of The coordinate system is a ground coordinate system, wherein the coordinate system is composed of XYZ coordinates of the kth vertex of the ith heliostat, N is the number of heliostats, m is the number of the vertices of the heliostats, and the common heliostats are rectangular, namely 4 vertices.
3. The method for calculating the shadow efficiency of the absorber tower to the mirror field in the tower type photo-thermal power station as set forth in claim 2, wherein the specific algorithm of the step S2 comprises the following steps: According to the tower height and shape of the heat absorption tower, calculating the corresponding target point of each heliostat according to the nearby principle or other principles, and setting as Wherein the target point According to the position of the sun Obtaining the included angles between the heliostat and the sun and between the heliostat and the target point by using the reflection theorem: ; Simultaneously calculating the normal vector of each heliostat: ; Wherein the method comprises the steps of Is the unit vector of the sun, Is the azimuth angle of the sun, For the solar altitude, the sign The inner product of the sun is calculated; finally, the obtained Normalized to a unit vector.
4. The method for calculating the shadow efficiency of the absorber tower to the mirror field in the tower type photo-thermal power station as set forth in claim 3, wherein in the step S3, the specific method for calculating the symmetrical position of the sun with respect to the absorber tower according to the sun position is as follows: Take the sun position at a certain moment Wherein For the azimuth angle of the sun, For the solar altitude, according to the law of direct light and the arrangement of the tower photo-thermal mirror field, the symmetrical position about the absorber tower is obtained: labeled new sun position, the unit vector of chemicals is expressed as: 。
5. The method for calculating the shadow efficiency of the absorber tower to the heliostat field in the tower-type photo-thermal power station as set forth in claim 4, wherein in the step S6, the specific method for calculating the shadow efficiency of the absorber tower to the heliostat is as follows: on the basis of judging whether the solution of the equation set is in the value range of the plane of the heat absorption tower and marking the blocked heliostats, calculating the heliostat shadow efficiency of the heat absorption tower on each blocked heliostat respectively by taking the proportion of the number of points/areas of the reflected light rays passing through the plane of the heat absorption tower and the total number of points/areas of the reflected light rays on the heliostats as the heliostat shadow efficiency; The shading efficiency of the heat absorption tower on the whole mirror field can be calculated by taking the proportion of the sum of the points/areas of the reflected light rays passing through the plane of the heat absorption tower in the mirror field and the sum of the total points/areas of the reflected light rays on all the heliostats in the mirror field as the shading efficiency of the mirror field.

Description

Method for calculating shadow efficiency of absorber tower to mirror field in tower type photo-thermal power station Technical Field The invention relates to the technical field of tower type photo-thermal stations, in particular to a method for calculating the shadow efficiency of a heat absorption tower in a tower type photo-thermal station on a lens field. Background The principle of the tower type solar thermal power generation system is that a large amount of low-density solar energy is reflected to a heat absorber to be changed into high-density solar energy through thousands of heliostats, and then the heat absorber utilizes a working medium stored in the heat absorber to be converted into working medium heat energy, and the heat energy can be converted into hot gas to be applied to petroleum exploitation, district heating and can be converted into electric energy, so that the electric power grid is integrated or hydrogen and the like are produced. The individual heliostats thus constitute a concentrating system that plays an extremely important role in a tower solar thermal power plant. Because the concentrating system needs to collect sunlight through a large number of heliostats to finally realize energy concentration, in the whole field design, the improvement of the optical efficiency of the heliostats, which is the ratio of the energy received by the heat absorber to the maximum energy received by the heliostats in the field, needs to be considered. The higher the optical efficiency of the heliostat, the greater the energy provided to the heat absorber and the higher the efficiency of the entire solar energy to working medium thermal energy. Optical efficiency generally includes cosine efficiency, shading or shadowing efficiency, and atmospheric transmission efficiency. However, for a large tower type photo-thermal mirror field, there is a factor affecting optical efficiency, namely, shielding of the heliostat by the heat absorption tower, the large tower type photo-thermal mirror field is characterized in that the heat absorption tower is often close to 200 meters in height, the formed shadow is as long as hundreds of meters, and the width is as long as tens of meters, and the influence on the heliostat near the shadow is extremely large, so that quantitative calculation of the influence of the shadow of the heat absorption tower on the heliostat is important. The conventional method for calculating the shadow efficiency of the heat absorption tower to the heliostat mainly comprises the steps of calculating the shadow of the heat absorption tower to the heliostat firstly and then reversely calculating the blocking of the heat absorption tower to the reflected light of the heliostat. In view of this, we propose a method of calculating the shading efficiency of the absorber tower to the mirror field in a tower photo-thermal power station. Disclosure of Invention The invention aims to provide a method for calculating the shadow efficiency of a heat absorption tower to a mirror field in a tower type photo-thermal power station, so as to solve the problems in the prior art. In order to solve the above technical problems, one of the purposes of the present invention is to provide a method for calculating the shadow efficiency of a heat absorption tower to a lens field in a tower type photo-thermal power station, comprising the following steps: S1, geometrically arranging heliostat fields to obtain heliostat position coordinates and vertex coordinates; S2, calculating a target point corresponding to each heliostat according to the tower height and shape of the heat absorption tower and a nearby principle or other principles, obtaining included angles between the heliostat and the sun and between the heliostat and the target point by using a reflection theorem according to the position of the sun, and simultaneously calculating a normal vector of each heliostat and normalizing the normal vector into a unit vector; s3, calculating the symmetrical position of the sun relative to the heat absorption tower according to the position of the sun; S4, according to the new sun position vector and the normal vector of each heliostat, calculating an included angle between the normal vector and the heliostat to the sun, and obtaining the reflected light corresponding to each heliostat at the moment by using a reflection theorem; S5, abstracting the heat absorption tower into a quadrilateral plane, obtaining four vertexes of the plane according to the tower height and the position of the heat absorption tower, substituting coordinates of the four vertexes into a plane equation, and finally obtaining a plane surrounded by the four vertexes; s6, calculating the shielding of the back-shadow of the heat absorption tower on the heliostat, marking the shielded heliostat, and further calculating the shadow efficiency of the heat absorption tower on the heliostat. As a further improvement of the present technical solution