Tower type solar thermal power station mirror field optical efficiency calculation method

Abstract

The application provides a kind of tower type solar thermal power station mirror field optical efficiency calculation method, belongs to tower type solar power field, solve mirror field optical efficiency large amount of calculation and low precision problem.Its technical scheme is: including the following steps: S1: obtaining mirror field parameters and solar position;S2: determine the atmospheric transmission efficiency and cosine efficiency of each heliostat;S3: calculate the shadow blocking efficiency of each heliostat;S4: calculate the truncation efficiency and optical efficiency of each heliostat.The beneficial effects of the application are: a kind of tower type solar thermal power station mirror field optical efficiency calculation method is designed, the method is gridded to the current heliostat, and the grid point and its adjacent heliostat vertex are projected to the mirror field horizontal plane along the incident light direction or the reflected light direction to calculate the shadow blocking efficiency, the heliostat that may be blocked is selected within a reasonable range, which greatly reduces the calculation amount of heliostat shadow blocking rate, and the operation accuracy is high, the method can ensure the calculation accuracy while improving the calculation speed of tower type solar power station mirror field optical efficiency simulation.

Description

Technical Field

[0001] This invention relates to the field of tower solar power generation, and more particularly to a method for calculating the optical efficiency of a mirror field in a tower solar thermal power plant. Background Technology

[0002] In recent years, among numerous solar energy utilization technologies, concentrated solar power (CSP) technology has seen significant development. Compared to the widely used photovoltaic (PV) power generation technology, CSP avoids the high pollution and high energy consumption problems associated with silicon cell production in PV. Combined with low-cost, large-scale heat storage technology, it can provide continuous, stable, and adjustable power output, making it more suitable for grid-connected power generation. Among CSP technologies, tower-type CSP is particularly favored due to its high heat collection efficiency.

[0003] In tower solar thermal power plants, the performance of the mirror field directly affects the solar energy absorption efficiency. Mirror field optical efficiency is a crucial performance indicator, encompassing cosine efficiency, shading efficiency, cutoff efficiency, atmospheric transmittance, and specular reflectivity. Among these, shading efficiency is the most challenging to calculate. Heliostats in the mirror field may be shaded or blocked by multiple neighboring heliostats, resulting in highly irregular shadow or shading patterns. Cheng Xiaolong, in his research "Research on Optimization Design of Mirror Field Layout in Tower Power Plants Based on Optical Efficiency," uses a geometric projection method to calculate the shading efficiency of heliostats. To reduce computational load, he assumes no overlapping shading portions during the calculation process; however, these assumptions significantly reduce the accuracy of the shading efficiency calculation. Hu Yeguang, in his research "Research on Multi-stage Reflective Concentrating Mirror Fields in Tower Solar Thermal Power Generation Systems," uses a numerical calculation method to calculate shading efficiency. This method projects neighboring heliostats along the direction of incident or reflected light onto the plane of the current heliostat to calculate the shading or blocking rate. This requires sequentially traversing each heliostat, resulting in high accuracy but a large computational burden. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of large computational load and low accuracy in the calculation of optical efficiency of mirror field in the prior art. The invention proposes a method for calculating the optical efficiency of mirror field in tower solar thermal power plants. This method improves the calculation speed of simulation of optical efficiency of mirror field in tower solar power plants while ensuring calculation accuracy.

[0005] This method first calculates the cosine efficiency and atmospheric transmittance of the heliostat field based on the sun's position and the mirror field's position. Second, it meshes the current heliostat and projects the mesh points and their neighboring heliostat vertices along the direction of incident or reflected light onto the mirror field plane to calculate the shading efficiency. Heliostats potentially prone to shading are selected within a reasonable range, significantly reducing the computational burden of calculating shading rates. Third, it calculates the truncation efficiency using the angle bisector method and ray tracing. Finally, it calculates the optical efficiency of the heliostat field.

[0006] The method for calculating the optical efficiency of a mirror field in a tower solar thermal power plant provided by this invention includes the following steps:

[0007] S1: Obtain the mirror field parameters and the position of the sun;

[0008] S2: Determine the atmospheric transmission efficiency and cosine efficiency of each heliostat;

[0009] S3: Calculate the shading efficiency of each heliostat;

[0010] S4: Calculate the cutoff efficiency and optical efficiency of each heliostat.

[0011] Step S1 includes the following steps:

[0012] Step 1.1: Construct a global coordinate system with the intersection of the central axis of the absorption tower and the mirror field plane as the origin, the east direction as the positive x-axis, the north direction as the positive y-axis, and the direction perpendicular to the ground upward as the positive z-axis.

[0013] Step 1.2: Assume the solar collector is of high H j Diameter R j The cylindrical external light-emitting solar collector has an absorption tower height (center height of the solar collector) of H.

[0014] Step 1.3: Set the dimensions of all heliostats to a×b, the installation height to h, and the minimum distance between adjacent heliostats to d. Based on the circular mirror field arrangement, obtain the mirror center O of the heliostat. i coordinates (x) i ,y i ,z i ), 1≤i≤N hel N hel This represents the total number of heliostats within the field of view.

[0015] Step 1.4: Calculate the solar azimuth angle α based on the latitude and longitude of the location of the mirror site. s and elevation angle γ s The calculation formula is as follows:

[0016]

[0017]

[0018] in The latitude is the local latitude, with north latitude being positive; ω is the solar hour angle. ST is the local time, and δ is the solar declination angle. Where D represents the number of days starting from day 0 of the spring breeze.

[0019] Step S2 includes the following steps:

[0020] Step 2.1: Calculate the center O of the heliostat i. i =(x i ,y i ,z i To the center of the solar collector O c = distance of (0,0,H) The calculation formula is as follows:

[0021]

[0022] Where H is the height of the collector center.

[0023] Step 2.2: Based on distance Calculate the atmospheric transmittance of heliostat i The calculation formula is as follows:

[0024]

[0025] Step 2.3: Based on the solar azimuth angle α s and elevation angle γ s Calculate the unit vector of the incident ray at different times. The formula is as follows:

[0026]

[0027] Step 2.4: Set the center O of the heliostat i. i =(x i ,y i ,z i ), collector center O c = (0,0,H), the reflected ray is represented as:

[0028]

[0029] Step 2.5: Based on the law of reflection and the incident ray and reflected light The unit normal vector of the i-th mirror of the heliostat can be obtained. Then the elevation angle of heliostat i and azimuth Represented as:

[0030]

[0031] Step 2.6: Using the unit vector of the incident ray and normal vector Solve for the cosine efficiency of heliostat i. The formula is as follows:

[0032]

[0033] Where θ i Let θ be the angle between the incident ray of the sun and the normal to the center of the heliostat i.

[0034] Step S3 includes the following steps:

[0035] Step 3.1: Idealize the absorption tower and collector as a whole into a high-H tol , long F tol A rectangle, after being illuminated by the sun, casts a rectangular shadow of length H on the ground. tol / tanα s Width is F tol The shaded areas of the absorption tower and the solar collector are represented as follows:

[0036]

[0037] Where, α s This is the solar altitude angle.

[0038] Step 3.2: Project the center point of the heliostat i onto the ground to obtain the coordinates of the projection point. Determine whether the projection point is within the shadow range of the absorption tower. If the projection point of the center of the mirror is within the shadow range, then the shadow rate of the heliostat i from the absorption tower and the solar collector is [value missing]. on the contrary,

[0039] Step 3.3: Discretize the heliostat mirror surface, where I×J is the number of all discrete points on heliostat i.

[0040] Step 3.4: Introduce a new coordinate system for each heliostat and establish the heliostat coordinate system C. i According to the elevation angle of heliostat i and azimuth Point P on the heliostat coordinate system can be obtained. k Coordinates in the global coordinate system:

[0041]

[0042] Step 3.5: Based on the incident light Determine the k-th discrete point P′ in heliostat i k =(P′) kx ,P′ ky ,P′ kz The projection P′ on the ground plane in the global coordinate system k Similarly, by determining the projections of four vertices of a heliostat j around heliostat i onto the ground plane in the global coordinate system, the projection region of the incident ray is obtained.

[0043]

[0044] Step 3.6: Determine the projection point P′ of each discrete point in heliostat i onto the ground plane. k 'Whether it is located within the projection area of ​​the incident ray of heliostat j, and count the number of discrete points located within other projection areas of the incident ray. Then the efficiency of heliostat i being occluded by the shadows of other heliostats is:

[0045]

[0046] Where I×J is the total number of discrete points on heliostat i.

[0047] Step 3.7: Calculate the unit vector of the reflected light on heliostat i according to the law of reflection. Right now

[0048]

[0049] Step 3.8: Based on the reflected light Determine the projection point P′ of each discrete point in heliostat i onto the ground plane. k "and the projection area of ​​the reflected light rays from the heliostat j on the ground plane in the global coordinate system."

[0050]

[0051] Step 3.9: Determine the projection point P′ of the reflected rays from discrete points on the light-collecting area of ​​heliostat i onto the ground plane. k "Whether it is located within the projection area of ​​the heliostat's reflected rays, and count the number of discrete points located within the projection areas of other reflected rays." The reflection blocking efficiency of heliostat i is:

[0052]

[0053] Where I×J is the total number of discrete points on heliostat i. Let be the number of discrete points on heliostat i located within the projection area of ​​other incident rays.

[0054] Step 3.10: Calculate the shading efficiency of heliostat i

[0055]

[0056] in, This indicates the shading rate of heliostat i due to the absorption tower and the solar collector. This indicates the occlusion efficiency of heliostat i when shaded by other heliostats. This represents the reflection and blocking efficiency of heliostat i.

[0057] Step S4 includes the following steps:

[0058] Step 4.1: Using the angle bisector method, divide the incident light cone of each beam of sunlight into S rays, where the radial angle and tangential angle of the p-th ray in the conical solar beam on heliostat i are respectively... 1≤p≤S and p is an integer.

[0059] Step 4.2: Calculate the coordinates in the heliostat coordinate system C i The unit vector of the p-th incident ray. Right now:

[0060]

[0061] in, These are the radial and tangential angles of the p-th ray on heliostat i, respectively.

[0062] Step 4.3: Based on the elevation angle of heliostat i and azimuth Calculate the coordinates of the unit vector of the incident ray in the global coordinate system:

[0063]

[0064] Step 4.4: Calculate the unit vector of the incident ray according to the law of reflection. Unit reflection vector on heliostat i Right now:

[0065]

[0066] in, Let be the unit normal vector of heliostat i.

[0067] Step 4.5: Set the discrete points of the reflective light spot on the sun mirror i as... 1≤g≤N i N i Let be the number of discrete points on heliostat i that can reflect light.

[0068] Step 4.6: Based on the reflected light Calculate discrete points At the collector plane x 2 +y 2 =R 2 The z-axis coordinates of the two projection points on the surface:

[0069]

[0070]

[0071] in,

[0072] R = R j / 2,R j The diameter of the solar collector.

[0073] Step 4.7: Judgment Is it in [HH] j / 2,H+H j Within the range of [ / 2], count the number of rays G that fall within this range at the intersection point of heliostat i. i Then the collector cutoff efficiency of heliostat i is

[0074]

[0075] Step 4.8: Optical efficiency η of the heliostat i The calculation formula is as follows:

[0076]

[0077] in, The specular reflectance is a constant. For the efficiency of shadow occlusion, For cosine efficiency, Atmospheric transmittance, Let be the cutoff efficiency of the solar collector. The formula for calculating the optical efficiency of the heliostat field is as follows:

[0078]

[0079] Where, N hel This represents the total number of heliostats in the heliostat field.

[0080] To better achieve the above-mentioned objectives, the present invention also provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the program, it implements the steps in the method for calculating the optical efficiency of the mirror field of the tower solar thermal power plant.

[0081] To better achieve the above-mentioned objectives, the present invention also provides a computer-readable storage medium storing a calculation program for the optical efficiency of a mirror field in a tower solar thermal power plant. When the computer program is executed by a processor, it implements the steps in the method for calculating the optical efficiency of the mirror field in the tower solar thermal power plant.

[0082] Compared with the prior art, the beneficial effects of the present invention are:

[0083] A method for calculating the optical efficiency of the mirror field in a tower-type solar thermal power plant is proposed. This method meshes the current heliostat and projects the mesh points and their adjacent heliostat vertices along the incident or reflected light direction onto the mirror field plane to calculate the shading efficiency. Heliostats potentially prone to shading are selected within a reasonable range, significantly reducing the computational workload of heliostat shading rate calculations and achieving high accuracy. Furthermore, this method considers the shading of the absorption tower when calculating the shading efficiency, further improving computational accuracy. In addition, this method employs the angle bisector method and ray tracing method when calculating the truncation efficiency, improving the computational speed of the tower-type solar power plant mirror field optical efficiency simulation while maintaining computational accuracy. Attached Figure Description

[0084] Figure 1 A flowchart illustrating the calculation method for the optical efficiency of the mirror field in a tower-type solar thermal power plant proposed in this invention;

[0085] Figure 2 The flowchart for "Calculating the shading efficiency of each heliostat" is provided for the calculation method of the optical efficiency of the mirror field in the tower solar thermal power plant proposed in this invention.

[0086] Figure 3 The flowchart for "Calculating the cutoff efficiency and optical efficiency of each heliostat" is provided for the calculation method of the optical efficiency of the mirror field in the tower solar thermal power plant proposed in this invention.

[0087] Figure 4 A schematic diagram of the solar azimuth and ray tracing in the global coordinate system for calculating the optical efficiency of the mirror field of the tower solar thermal power plant proposed in this invention.

[0088] Figure 5 A schematic diagram of ray tracing in the global coordinate system for calculating the optical efficiency of the mirror field in the tower solar thermal power plant proposed in this invention;

[0089] Figure 6 The working principle diagram of the circular heliostat field for the calculation method of the optical efficiency of the mirror field in the tower solar thermal power plant proposed in this invention;

[0090] Figure 7 A schematic diagram of heliostat shading for the calculation method of the optical efficiency of the mirror field in the tower solar thermal power plant proposed in this invention.

[0091] Figure 8 A schematic diagram of the shadow projection of incident light along the heliostat between the heliostats, illustrating the method for calculating the optical efficiency of the mirror field in a tower-type solar thermal power plant proposed in this invention.

[0092] Figure 9 This is a schematic diagram of the focused light spot of the heliostat reflected light, which is used in the calculation method of the optical efficiency of the mirror field of the tower solar thermal power plant proposed in this invention. Detailed Implementation

[0093] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments.

[0094] Example 1

[0095] See Figures 1 to 9 This embodiment provides a method for calculating the optical efficiency of the mirror field in a tower solar thermal power plant. The calculation method includes the following steps:

[0096] S1: Obtain the mirror field parameters and the position of the sun;

[0097] S2: Determine the atmospheric transmission efficiency and cosine efficiency of each heliostat;

[0098] S3: Calculate the shading efficiency of each heliostat;

[0099] S4: Calculate the cutoff efficiency and optical efficiency of each heliostat.

[0100] Specifically, in step S1, the method for calculating the optical efficiency of the mirror field of the tower solar thermal power plant includes:

[0101] Step 1.1: Construct a global coordinate system with the intersection of the central axis of the absorption tower and the mirror field plane as the origin, the east direction as the positive x-axis, the north direction as the positive y-axis, and the direction perpendicular to the ground upward as the positive z-axis.

[0102] Step 1.2: Assume the solar collector is of high H j =8m, diameter R j A cylindrical external light-emitting solar collector with a height of 7m has an absorption tower height (center height of the solar collector) of H = 80m.

[0103] Step 1.3: Set the dimensions of all heliostats to 6m × 6m, the installation height to 4m, and the distance between adjacent heliostats to be d ≥ 11m. Based on the circular mirror field arrangement, obtain the center O of the heliostat's mirror surface. i coordinates (x) i ,y i ,z i ), 1≤i≤1745, where 1745 is the total number of heliostats in the field.

[0104] Step 1.4: Calculate the solar azimuth angle α based on the latitude and longitude of the location of the mirror site. s and elevation angle γ s The calculation formula is as follows:

[0105]

[0106]

[0107] in The latitude is the local latitude, with north latitude being positive; ω is the solar hour angle. ST is the local time, and δ is the solar declination angle. Where D represents the number of days starting from day 0 of the spring breeze.

[0108] Specifically, in step S2, the method for calculating the optical efficiency of the mirror field of the tower solar thermal power plant includes:

[0109] Step 2.1: Calculate the center O of the heliostat i. i =(x i ,y i ,z i To the center of the solar collector O c = distance of (0,0,H) The calculation formula is as follows:

[0110]

[0111] Where H is the height of the collector center.

[0112] Step 2.2: Based on distance Calculate the atmospheric transmittance of heliostat i The calculation formula is as follows:

[0113]

[0114] Step 2.3: Based on the solar azimuth angle α s and elevation angle γ s Calculate the unit vector of the incident ray at different times. The formula is as follows:

[0115]

[0116] Step 2.4: Set the center O of the heliostat i. i =(x i ,y i ,z i ), collector center O c = (0,0,H), the reflected ray is represented as:

[0117]

[0118] Step 2.5: Based on the law of reflection and the incident ray and reflected light The unit normal vector of the i-th mirror of the heliostat can be obtained. Then the elevation angle of heliostat i and azimuth Represented as:

[0119]

[0120] Step 2.6: Using the unit vector of the incident ray and normal vector Solve for the cosine efficiency of heliostat i. The formula is as follows:

[0121]

[0122] Where θ i Let θ be the angle between the incident ray of the sun and the normal to the center of the heliostat i.

[0123] Specifically, in step S3, the method for calculating the optical efficiency of the mirror field of the tower solar thermal power plant includes:

[0124] Step 3.1: Idealize the absorption tower and collector as a whole into a high-H tol =84m, length F tol A rectangle with a length of 7m casts a rectangular shadow on the ground after being illuminated by the sun. The shadow's length is H. tol / tanα s Width is F tol The shaded areas of the absorption tower and the solar collector are represented as follows:

[0125]

[0126] Where, α s This is the solar altitude angle.

[0127] Step 3.2: Project the center point of the heliostat i onto the ground to obtain the coordinates of the projection point. Determine whether the projection point is within the shadow range of the absorption tower. If the projection point of the center of the mirror is within the shadow range, then the shadow rate of the heliostat i from the absorption tower and the solar collector is [value missing]. on the contrary,

[0128] Step 3.3: Discretize the heliostat mirror surface, where I×J is the number of all discrete points on heliostat i.

[0129] Step 3.4: Introduce a new coordinate system for each heliostat and establish the heliostat coordinate system C. i According to the elevation angle of heliostat i and azimuth Point P on the heliostat coordinate system can be obtained. k Coordinates in the global coordinate system:

[0130]

[0131] Step 3.5: Based on the incident light Determine the k-th discrete point P′ in heliostat i k =(P′) kx ,P′ ky ,P′ kz The projection P′ on the ground plane in the global coordinate system k Similarly, by determining the projections of four vertices of a heliostat j around heliostat i onto the ground plane in the global coordinate system, the projection region of the incident ray is obtained.

[0132]

[0133] Step 3.6: Determine the projection point P′ of each discrete point in heliostat i onto the ground plane. k 'Whether it is located within the projection area of ​​the incident ray of heliostat j, and count the number of discrete points located within other projection areas of the incident ray. Then the efficiency of heliostat i being occluded by the shadows of other heliostats is:

[0134]

[0135] Where I×J is the total number of discrete points on heliostat i.

[0136] Step 3.7: Calculate the unit vector of the reflected light on heliostat i according to the law of reflection. Right now

[0137]

[0138] Step 3.8: Based on the reflected light Determine the projection point P′ of each discrete point in heliostat i onto the ground plane. k "and the projection area of ​​the reflected light rays from the heliostat j on the ground plane in the global coordinate system."

[0139]

[0140] Step 3.9: Determine the projection point P′ of the reflected rays from discrete points on the light-collecting area of ​​heliostat i onto the ground plane. k "Whether it is located within the projection area of ​​the heliostat's reflected rays, and count the number of discrete points located within the projection areas of other reflected rays." The reflection blocking efficiency of heliostat i is:

[0141]

[0142] Where I×J is the total number of discrete points on heliostat i. Let be the number of discrete points on heliostat i located within the projection area of ​​other incident rays.

[0143] Step 3.10: Calculate the shading efficiency of heliostat i

[0144]

[0145] in, This indicates the shading rate of heliostat i due to the absorption tower and the solar collector. This indicates the occlusion efficiency of heliostat i when shaded by other heliostats. This represents the reflection and blocking efficiency of heliostat i.

[0146] Specifically, in step S4, the method for calculating the optical efficiency of the mirror field of the tower solar thermal power plant includes:

[0147] Step 4.1: Using the angle bisector method, divide the incident light cone of each beam of sunlight into S rays, where the radial angle and tangential angle of the p-th ray in the conical solar beam on heliostat i are respectively... 1≤p≤S and p is an integer.

[0148] Step 4.2: Calculate the coordinates in the heliostat coordinate system C i The unit vector of the p-th incident ray. Right now:

[0149]

[0150] in, These are the radial and tangential angles of the p-th ray on heliostat i, respectively.

[0151] Step 4.3: Based on the elevation angle of heliostat i and azimuth Calculate the coordinates of the unit vector of the incident ray in the global coordinate system:

[0152]

[0153] Step 4.4: Calculate the unit vector of the incident ray according to the law of reflection. Unit reflection vector on heliostat i Right now:

[0154]

[0155] in, Let be the unit normal vector of heliostat i.

[0156] Step 4.5: Set the discrete points of the reflective light spot on the sun mirror i as... 1≤g≤N i M i Let be the number of discrete points on heliostat i that can reflect light.

[0157] Step 4.6: Based on the reflected light Calculate discrete points At the collector plane x 2 +y 2 =R 2 The z-axis coordinates of the two projection points on the surface:

[0158]

[0159]

[0160] in,

[0161] R = R j / 2,R j The diameter of the solar collector.

[0162] Step 4.7: Judgment Is it in [HH] j / 2,H+H j Within the range of [ / 2], count the number of rays G that fall within this range at the intersection point of heliostat i. i Then the collector cutoff efficiency of heliostat i is

[0163]

[0164] Step 4.8: Optical efficiency η of the heliostat i The calculation formula is as follows:

[0165]

[0166] in, The specular reflectance is a constant. For the efficiency of shadow occlusion, For cosine efficiency, Atmospheric transmittance, Let be the cutoff efficiency of the solar collector. The formula for calculating the optical efficiency of the heliostat field is as follows:

[0167]

[0168] Here, 1745 represents the total number of heliostats in the heliostat field.

[0169] The present invention also provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the program, it implements the steps in the method for calculating the optical efficiency of the mirror field of a tower solar thermal power plant.

[0170] The present invention also provides a computer-readable storage medium storing a calculation program for the optical efficiency of a mirror field in a tower solar thermal power plant. When the computer program is executed by a processor, it implements the steps in the method for calculating the optical efficiency of a mirror field in a tower solar thermal power plant.

Claims

1. A method for calculating the optical efficiency of a mirror field in a tower-type solar thermal power plant, characterized in that: Specifically, the following steps are included: S1: Obtain the mirror field parameters and the position of the sun; S2: Determine the atmospheric transmission efficiency and cosine efficiency of each heliostat; S3: Calculate the shading efficiency of each heliostat; Step S3 includes the following steps: Step 3.1: Set the absorption tower and collector as a whole as a high-pressure unit. ,long A rectangle, after being illuminated by the sun, casts a rectangular shadow on the ground with a length of [length missing]. , width is The shaded areas of the absorption tower and the solar collector are represented as follows: ； in, This is the solar azimuth angle; Step 3.2: Place the heliostat The center point of the heliostat is projected onto the ground to obtain the coordinates of the projection point. It is then determined whether the projection point lies within the shadow area of ​​the absorption tower. If the projection point of the center point of the heliostat is within the shadow area, then the heliostat... The shading rate of the absorption tower and the collector ,on the contrary, ; Step 3.3: Discretize the heliostat mirror surface. For heliostats The number of all discrete points; Step 3.4: Establish a new coordinate system for each heliostat. According to the heliostat altitude angle and azimuth Points on the heliostat coordinate system can be obtained. Coordinates in the global coordinate system: ； Step 3.5: Based on the incident light Determine the heliostat The Middle discrete points Projection onto the ground plane in the global coordinate system Similarly, determining the heliostat A certain heliostat in the vicinity Projecting the incident ray onto the four vertices of the ground plane in the global coordinate system yields the projection region of the incident ray. ； Step 3.6: Determine the heliostat The projection of each discrete point on the ground plane Is it located at a heliostat? Within the projection area of ​​the incident ray, count the number of discrete points located within the projection areas of other incident rays. Then the sundial The shading efficiency of other heliostats is: ； in, For heliostats The total number of all discrete points; Step 3.7: Calculate the heliostat's position based on the law of reflection. Unit vector of reflected light ; Step 3.8: Based on the reflected light Determine the heliostat The projection of each discrete point on the ground plane and heliostat The projection area of ​​reflected light rays on the ground plane in the global coordinate system; ； Step 3.9: Determine the heliostat The projection points of reflected rays from discrete points on the light-receiving area onto the ground plane Is it located at a heliostat? Within the projection area of ​​the reflected ray, count the number of discrete points located within the projection areas of other reflected rays. Then the sundial The reflection blocking efficiency is: ； in, For heliostats The total number of all discrete points. For heliostats The number of discrete points located within the projection area of ​​other incident rays; Step 3.10: Calculate the heliostat Shadow occlusion efficiency : ； in, Indicates heliostat The shading rate of the absorption tower and the collector Indicates heliostat Due to the shading and obstruction efficiency of other heliostats, Indicates heliostat The efficiency of reflection blocking; S4: Calculate the cutoff efficiency and optical efficiency of each heliostat.

2. The method for calculating the optical efficiency of the mirror field in a tower solar thermal power plant according to claim 1, characterized in that: Step S1 includes the following steps: Step 1.1: Construct a global coordinate system with the intersection of the central axis of the absorption tower and the mirror field plane as the origin, the east direction as the positive x-axis, the north direction as the positive y-axis, and the direction perpendicular to the ground upward as the positive z-axis; Step 1.2: Assume the solar collector is high-temperature resistant. ,diameter A cylindrical external light-emitting solar collector, with an absorption tower height of ; Step 1.3: Set the dimensions of the sun mirror to be [size missing]. The installation height is The minimum distance between adjacent heliostats is Based on the circular mirror field arrangement, the center of the heliostat mirror surface is obtained. coordinates , The total number of heliostats within the field of view; Step 1.4: Calculate the solar azimuth angle based on the latitude and longitude of the location of the mirror site. and elevation angle .

3. The method for calculating the optical efficiency of the mirror field in a tower solar thermal power plant according to claim 2, characterized in that: Step S2 includes the following steps: Step 2.1: Calculate the heliostat The center of the mirror To the solar collector center distance ; Step 2.2: Based on distance Calculation of heliostats Atmospheric transmittance ; Step 2.3: Based on the solar azimuth angle and elevation angle Calculate the unit vector of the incident ray at different times. ; Step 2.4: Set the sun mirror The center of the mirror Center of the solar collector The reflected ray is represented as: ; Step 2.5: Based on the law of reflection and the incident ray and reflected light The heliostat can be obtained. Unit normal vector of the mirror Then the sundial altitude angle and azimuth Represented as: ； Step 2.6: Using the unit vector of the incident ray and normal vector Solve for the heliostat problem. cosine efficiency The formula is as follows: ； in For the incident sunlight and the heliostat The angle between the center normal of the mirror surface.

4. The method for calculating the optical efficiency of the mirror field in a tower solar thermal power plant according to claim 3, characterized in that: Step S4 includes the following steps: Step 4.1: Divide the incident light cone of each beam of sunlight into equal parts using the angle bisector method. A ray of light, in which the heliostat The first in the upper conical solar beam The radial angle and tangential angle of the ray are respectively , and It is an integer; Step 4.2: Calculate the coordinates in the heliostat coordinate system The next Unit vector of incident light ,Right now: ； in, Heliostats Upper The radial and tangential angles of a ray; Step 4.3: According to the heliostat altitude angle and azimuth Calculate the coordinates of the unit vector of the incident ray in the global coordinate system: ; Step 4.4: Calculate the unit vector of the incident ray according to the law of reflection. In heliostat Unit reflection vector on ; Step 4.5: Set up the sun mirror The discrete points of the reflective light spot are , For heliostats The number of discrete points on the reflective light spot; Step 4.6: Based on the reflected light Calculate discrete points On the solar collector plane The two projection points on Axis coordinates: ； ； in, ; , The diameter of the solar collector; Step 4.7: Determine Is it in Within the range, statistical heliostats The number of light rays falling within this range at the upper intersection point Then the sundial The collector cutoff efficiency is: ； Step 4.8: Optical efficiency of the heliostat The calculation formula is as follows: ； in, The specular reflectance is a constant. For the efficiency of shadow occlusion, For cosine efficiency, Atmospheric transmittance, The formula for calculating the optical efficiency of the heliostat field, given the cutoff efficiency of the solar collector, is as follows: ； in, This represents the total number of heliostats in the heliostat field.

5. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor, when executing the program, implements the method as described in any one of claims 1-4.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program for the optical efficiency of the mirror field of a tower solar thermal power plant, which, when executed by a processor, implements the method as described in any one of claims 1 to 4.

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