Design method for constructing uniform condenser for plate-shaped absorber based on plane reflection unit

Abstract

The invention relates to a design method for constructing a uniform condenser for a plate-shaped absorber based on a plane reflection unit, and belongs to the technical field of solar photovoltaic photo-thermal. The uniform condenser comprises a solar photovoltaic panel and plane reflectors, and the plane reflectors are obliquely and symmetrically arranged on the two sides of the solar photovoltaic panel and used for uniformly reflecting solar rays incident to the plane reflectors to cover the whole light receiving surface of the solar photovoltaic panel. The method comprises the following steps: acquiring initial design parameters, establishing a mathematical model of a geometrical relationship of each planar mirror of the uniform condenser, calculating structural parameters (an included angle alpha n, an inclination angle beta n and a width Dn) of each planar mirror, simulating a drop point position of light on a condenser model constructed according to the mathematical model by using ray tracing software Tracepro, and verifying the reliability of the mathematical model; the method comprises the following steps: simulating the energy flux density distribution on the surface of a solar photovoltaic panel under the condition of sunlight vertical incidence, namely an incidence angle of 0 degree, by utilizing ray tracing software Tracepro, and verifying the uniformity of the energy flux density distribution.

Description

TECHNICAL FIELD

[0001] The application relates to a design method for constructing a uniform condenser for a plate-shaped absorber based on a plane reflecting unit and belongs to the technical field of solar photovoltaic and photo-thermal technologies. BACKGROUND

[0002] Solar light condensation technology improves the energy flow density per unit area by concentrating sunlight, which is of great significance to improving photovoltaic power generation efficiency, increasing photo-thermal conversion temperature and reducing the cost of solar utilization systems. In the field of photovoltaic and photo-thermal comprehensive utilization (PV / T), a flat plate absorber with compact structure and easy integration shows a good application prospect. However, when the traditional condenser is applied to the fixed flat plate absorber, there is a key defect that the concentrated light spot is extremely unevenly distributed on the surface of the absorber. Usually, the energy flow density in the central area is too high, while the light intensity in the edge area is insufficient.

[0003] This light spot unevenness has serious consequences: for the photovoltaic part, local hot spots cause the cell temperature to rise sharply, resulting in significant degradation of photoelectric conversion efficiency and easily inducing "hot spot effect", which leads to permanent damage to the cell and safety hazards; for the photo-thermal or PV / T part, the extremely high local thermal load can accelerate material aging and produce thermal stress, leading to deformation or even cracking of components, which seriously damages the long-term reliability and comprehensive performance of the system. To avoid the above damage, the system is often forced to reduce the condensing ratio or use a complex and expensive cooling scheme, which greatly limits the optimization space of efficiency and cost.

[0004] In the prior art, in order to improve the condensation uniformity, schemes such as complex curved surface condenser design or moving the absorber are proposed. However, these methods generally have problems such as high processing difficulty, high manufacturing cost, complex system structure, introduction of additional optical loss or influence on heat dissipation reliability. Therefore, developing a condenser structure design method which can realize highly uniform energy flow density distribution on the surface of the flat plate absorber and has simple structure and low cost has become a key technical problem to be solved in the field of solar energy utilization. SUMMARY

[0005] In view of the defects of uneven energy flow density distribution on the surface of the flat plate absorber caused by the condenser in the prior art, as well as the complex structure and high cost, the application provides a design method for constructing a uniform condenser for a plate-shaped absorber based on a plane reflecting unit. By establishing an accurate geometric-optical mathematical model, the key structural parameters of each plane mirror are determined to ensure that the vertically incident sunlight can uniformly cover the surface of the solar photovoltaic plate after being reflected.

[0006] A design method for constructing a uniform condenser for a plate-shaped absorber based on a plane reflecting unit, the uniform condenser comprising a solar photovoltaic panel 1 and plane mirrors 2 symmetrically arranged on both sides of the solar photovoltaic panel 1 to uniformly reflect the sunlight incident on the plane mirrors 2 to cover the entire light-receiving surface of the solar photovoltaic panel 1; The specific steps are as follows: S1. Obtain initial design parameters, the number of single-sided plane mirrors is N, the solar photovoltaic panel is located at the lowest end, and the serial numbers of the single-sided nth plane mirror from bottom to top are 1, 2, …, N, the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel is α1, the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel is L, and the width of the solar photovoltaic panel is W; S2. Based on the initial design parameters, a mathematical model of the geometric relationship of each plane mirror of the uniform condenser is established, and the structure parameters of each plane mirror are calculated; the structure parameters include the angle αn between the lower end point of the nth plane mirror and the surface of the solar photovoltaic panel, the inclination angle βn of the nth plane mirror, and the width Dn of the nth plane mirror; n n n ; S3. Use the ray tracing software Tracepro to simulate the reflection path and landing point position of the sunlight vertically incident, i.e., the incident angle is 0°, on the condenser model constructed according to the mathematical model, compare the simulated landing point position with the theoretically predicted position of the mathematical model, and verify the reliability of the mathematical model; S4. Use the ray tracing software Tracepro to simulate the energy flux density distribution of each region on the surface of the solar photovoltaic panel under the condition that the sunlight is vertically incident, i.e., the incident angle is 0°, and verify the uniformity of the energy flux density distribution by analyzing the energy flux density distribution diagram.

[0007] Preferably, the mathematical model in step S2 is: Take the first plane mirror (n=1) as an example (see Figure 12 ), and the derivation process is as follows: Let the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel be α1, the distance between the lower end point and the starting absorption point of the solar photovoltaic panel be L, and the width of the solar photovoltaic panel be W.

[0008] When the sunlight is vertically incident, the entire light-receiving surface of the solar photovoltaic panel needs to be covered after being reflected by the first plane mirror; let the lower end point of the mirror be C, the upper end point be D, and the left and right end points of the photovoltaic panel be A and B, respectively, then the light rays reflected by points C and D should fall on points A and B, respectively; from the geometric relationship, we have: 1. Extend DC to intersect AB at point E, and let ∠CEF=β1, which is the inclination angle of the first plane mirror;​​ 2. According to the law of reflection, the incident angle is equal to the reflection angle, so the reflection angle nCB=β1; 3. In triangle BCE, according to the complementary angle relationship and the trigonometric function formula, the calculation formula of β1 can be solved; 4. Translate AB to GC, in triangle CDG, CG=W, CD=D1, ∠DGC=α1, ∠CDG=β1-α1, combining the sine theorem, the expression of D1 can be solved; Thus, the mathematical model formula when n=1 is obtained: ; In the formula, W is the width of the solar photovoltaic panel, L is the distance between the lower end point of the first flat mirror and the starting absorption point of the solar photovoltaic panel, α1 is the angle between the lower end point of the first flat mirror and the surface of the solar photovoltaic panel, β1 is the inclination angle of the first flat mirror, and D1 is the width of the first flat mirror.

[0009] For the nth mirror when n=2 and beyond, the same geometric construction and derivation method can be used: The upper end point of the previous mirror is taken as the lower end point of the current mirror; Let the angle between the lower end point and the surface of the photovoltaic panel be α n ; According to the same geometric relationship as n=1, the calculation formula of the inclination angle β n and the width D n is derived.

[0010] Therefore, when n=2, β2 and D2 can be deduced by analogy; when n≥3, the same applies; through recursive method, the structural parameters of any nth flat mirror can be obtained.

[0011] When n=1, the mathematical model is: ; In the formula, W is the width of the solar photovoltaic panel, L is the distance between the lower end point of the first flat mirror and the starting absorption point of the solar photovoltaic panel, α1 is the angle between the lower end point of the first flat mirror and the surface of the solar photovoltaic panel, β1 is the inclination angle of the first flat mirror, and D1 is the width of the first flat mirror; When n=2, the mathematical model is: ; In the formula, α2 is the angle between the lower end point of the second flat mirror and the surface of the solar photovoltaic panel, β2 is the inclination angle of the second flat mirror, and D2 is the width of the second flat mirror; When 3≤n≤N, the mathematical model is: ; In the formula, α n is the angle between the lower end point of the nth flat mirror and the surface of the solar photovoltaic panel, β n is the inclination angle of the nth flat mirror, D n is the width of the nth flat mirror.

[0012] Preferably, the method for verifying the reliability of the mathematical model in step S3 is: using the ray tracing software Tracepro to perform ray tracing simulation on the uniform concentrator model constructed according to the mathematical model under the condition that the incident angle is 0°, and recording the landing position of each ray on the absorption surface; comparing the simulation landing points with the theoretically predicted landing points of the mathematical model point by point, calculating the root mean square error (RMSE) and the maximum deviation (e max ); if RMSE≤1mm and e max ≤2mm, it is determined that the mathematical model is reliable; otherwise, the mirror inclination angle (adjustment range is ±1°) and the width (adjustment range is ±2mm) parameters are adjusted to recalculate and simulate until the determination condition is met.

[0013] Preferably, the method for verifying the uniformity of the energy flow density distribution in step S4 is: simulating the concentrator model constructed according to the mathematical model in Tracepro under the condition that the incident angle is 0°, obtaining the energy flow density distribution on the absorption surface; calculating the average value of the energy flow density and comparing it with the energy flow density of each point; if the energy flow density of all regions deviates from the average value by no more than ±10%, it is considered that the energy flow density distribution is uniform; otherwise, the mirror inclination angle (adjustment range is ±1°) and the width (adjustment range is ±2mm) parameters are adjusted to redesign until the determination condition is met.

[0014] The beneficial effects of the present application are: (1) The energy flow distribution of the present application is highly uniform: through the accurate mathematical model design of the layout and parameters of the flat mirror, the serious spot unevenness problem in the traditional flat mirror concentrating system can be effectively eliminated, the uniform distribution of the energy flow density on the absorption surface is realized, and the extremely dangerous local "hot spot" phenomenon is completely avoided; (2) The present application improves performance and reliability: the uniform energy flow distribution significantly improves the power generation efficiency and service life of the photovoltaic cell (avoids hot spot effect), while reducing the material aging, thermal stress and failure risk of the photothermal or PV / T component caused by local overheating, improving the long-term operation reliability and comprehensive performance of the entire system; (3) The present application is simple to process and low in cost: using standard flat mirrors instead of complex curved mirrors greatly reduces the processing difficulty and manufacturing cost, which is conducive to large-scale commercial application and promotion; (4) The present application has a simple and compact structure: the device structure is simple, mainly composed of a flat photovoltaic panel and an array of flat mirrors on both sides, easy to integrate and install. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The schematic diagram of the overall structure of the uniform condenser; Figure 2 The schematic diagram of the initial design parameters of the uniform condenser; Figure 3 The schematic diagram of the geometric parameters of the uniform condenser when n=1; Figure 4 The schematic diagram of the light spot position simulated by the Tracepro software to verify the model when n=1 (incident angle 0°); Figure 5 The schematic diagram of the surface energy flow density distribution of the solar photovoltaic panel simulated by the Tracepro software when n=1 (incident angle 0°); Figure 6 The schematic diagram of the geometric parameters of the uniform condenser when n=2; Figure 7 The schematic diagram of the light spot position simulated by the Tracepro software to verify the model when n=2 (incident angle 0°); Figure 8 The schematic diagram of the surface energy flow density distribution of the solar photovoltaic panel simulated by the Tracepro software when n=2 (incident angle 0°); Figure 9 The schematic diagram of the geometric parameters of the uniform condenser when n=3; Figure 10 The schematic diagram of the light spot position simulated by the Tracepro software to verify the model when n=3 (incident angle 0°); Figure 11 The schematic diagram of the surface energy flow density distribution of the solar photovoltaic panel simulated by the Tracepro software when n=3 (incident angle 0°); Figure 12 The schematic diagram of the mathematical model formula derivation. DETAILED DESCRIPTION

[0016] The application will be described in further detail below with reference to the specific embodiments, but the scope of protection of the application is not limited to the described content.

[0017] The uniform condenser in the embodiment of the application comprises a solar photovoltaic panel 1 and a plane mirror 2, which is symmetrically arranged on the two sides of the solar photovoltaic panel 1 and used to uniformly reflect the sunlight incident to the plane mirror 2 to the entire light-receiving surface of the solar photovoltaic panel 1 (see Figure 1 ).

[0018] Embodiment 1: Taking the case of arranging one plane mirror on one side (n=1), a design method of constructing a uniform condenser for a plate-shaped absorber based on a plane reflection unit (seeFigure 2 and 3 ), the specific steps are as follows: S1. Obtain the initial design parameters, the number of single-sided plane mirrors is 1, the solar photovoltaic panel is located at the lowest end, the included angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel is α1=30°, the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel is L=2mm, and the width of the solar photovoltaic panel is W=156mm; the design irradiation of the uniform condenser is 1000W / m 2 ; S2. Based on the initial design parameters, a mathematical model of the geometric relationship of each plane mirror of the uniform condenser is established, and the structure parameters of each plane mirror are calculated; the structure parameters include the included angle α1 between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel, the inclination angle β1 of the first plane mirror, and the width D1 of the first plane mirror; When n=1, the mathematical model is: ; In the formula, W is the width of the solar photovoltaic panel, L is the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel, α1 is the included angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel, β1 is the inclination angle of the first plane mirror, and D1 is the width of the first plane mirror; Through calculation, the inclination angle β1 of the first plane mirror is 60° and the width D1 of the first plane mirror is 156mm; According to the initial design parameters, the inclination angle β1 (60°) and the width D1 (156mm) of the first plane mirror, a uniform condenser model is accurately constructed in a three-dimensional modeling software; S3. The light ray tracing software Tracepro is used to perform light ray tracing simulation on the uniform condenser model constructed according to the mathematical model under the condition that the incident angle is 0°, and the landing position of each ray on the absorption surface is recorded (see Figure 4 ); the simulation landing points are compared with the theoretically predicted landing points of the mathematical model point by point, and the root mean square error RMSE (0.66mm) and the maximum deviation e max (1.64mm) are calculated; according to the mathematical model reliability determination method, if RMSE≤1mm and e max ≤2mm, it is determined that the mathematical model is reliable; otherwise, the parameters such as the inclination angle of the mirror (allowing adjustment of ±1°) and the width (allowing adjustment of ±2mm) are adjusted, and the calculation and simulation are performed again until the determination condition is met; therefore, the root mean square error RMSE (0.66mm) of the embodiment is less than 1mm, and e max (1.64mm) is less than 2mm, and the mathematical model is reliable; S4. Simulate the concentrator model constructed according to the mathematical model in Tracepro under the condition of the incident angle of 0° to obtain the energy flux density distribution on the absorption surface (see Figure 5 ); calculate the average value of the energy flux density (the average energy flux density is 1.89 kW / m 2 ), and compare it with the energy flux density of each point; according to the energy flux density distribution uniformity judgment method, if the energy flux density of all regions deviates from the average value by no more than ±10%, the energy flux density distribution is considered to be uniform; otherwise, the parameters such as the tilt angle (allowing adjustment of ±1°) and the width (allowing adjustment of ±2 mm) of the mirror are adjusted to redesign until the judgment condition is met; The deviation of the energy flux density of all regions in this embodiment from the average value is 4.8%, which is less than the threshold value 10%, so the energy flux density distribution on the absorption surface in this embodiment is uniform.

[0019] Embodiment 2: Taking the case of setting two plane mirrors on one side (n=2) as an example, a design method for constructing a uniform concentrator for a plate-shaped absorber based on a plane reflection unit (see Figure 6 ), the specific steps are as follows: S1. Obtain the initial design parameters, the number of plane mirrors on one side is 2, the solar photovoltaic panel is located at the lowest end, and the serial numbers of the plane mirrors on one side from bottom to top are 1 and 2; the angle α1 between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel is 34.4°, the distance L between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel is 2 mm, and the width W of the solar photovoltaic panel is 156 mm; the design irradiance of the uniform concentrator is 1000 W / m 2 ; S2. Based on the initial design parameters, a mathematical model of the geometric relationship of each plane mirror of the uniform concentrator is established, and the structure parameters of each plane mirror are calculated; the structure parameters include the angle α n between the lower end point of the nth (n=1 and 2) plane mirror and the surface of the solar photovoltaic panel, the tilt angle β n of the nth plane mirror, and the width D n of the nth plane mirror; When n=1, the mathematical model is: ; In the formula, W is the width of the solar photovoltaic panel, L is the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel, α1 is the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel, β1 is the tilt angle of the first plane mirror, and D1 is the width of the first plane mirror; When n=2, the mathematical model is: ; In the formula, α2 is the angle between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, β2 is the inclination angle of the second plane mirror, and D2 is the width of the second plane mirror. Through calculation, the inclination angle β1 (62.2°) and the width D1 (189.3 mm) of the first plane mirror are obtained; at the same time, the position of the upper end point of the first plane mirror is calculated, the angle α2 (61.9°) between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel is determined, and the inclination angle β2 (76.0°) of the second plane mirror is calculated according to the angle α2 (61.9°) between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, and D2 is the width D2 (567.8 mm) of the second plane mirror. According to the initial design parameters, the inclination angle β1 (62.2°) and the width D1 (189.3 mm) of the first plane mirror, and the angle α2 (61.9°), the inclination angle β2 (76.0°) and the width D2 (567.8 mm) between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, a uniform concentrator model is accurately constructed in a three-dimensional modeling software. S3. The light ray tracing software Tracepro is used to perform light ray tracing simulation on the uniform concentrator model constructed according to the mathematical model under the condition that the incident angle is 0°, and the landing position of each ray on the absorption surface is recorded (see Figure 7 ); the simulation landing points are compared with the theoretically predicted landing points of the mathematical model point by point, and the root mean square error RMSE (0.32 mm) and the maximum deviation e max (1.08 mm) are calculated; according to the mathematical model reliability determination method, if RMSE≤1 mm and e max ≤2 mm, the mathematical model is determined to be reliable; otherwise, the parameters such as the inclination angle (allowing adjustment of ±1°) and the width (allowing adjustment of ±2 mm) of the mirror are adjusted to recalculate and simulate until the determination condition is met; therefore, the root mean square error RMSE (0.32 mm) of the embodiment is less than 1 mm, and e max (1.08 mm) is less than 2 mm, and the mathematical model is reliable. S4. The concentrator model constructed according to the mathematical model is simulated in Tracepro under the condition that the incident angle is 0°, and the energy flux density distribution on the absorption surface is obtained (see Figure 8 ); the average value of the energy flux density (the average energy flux density is 2.75 kW / m 2 ) is calculated, and compared with the energy flux density of each point; according to the energy flux density distribution uniformity determination method, if the energy flux density of all regions deviates from the average value by not more than ±10%, the energy flux density distribution is considered to be uniform; otherwise, the parameters such as the inclination angle (allowing adjustment of ±1°) and the width (allowing adjustment of ±2 mm) of the mirror are adjusted to redesign until the determination condition is met. The energy flow density of the whole area of the embodiment deviates from the average value by 0.4%, which is less than the threshold value 10%, so the energy flow density distribution on the absorption surface of the embodiment is uniform.

[0020] Embodiment 3: Taking the case of setting three plane mirrors on one side (n=3) as an example, a design method for constructing a uniform condenser for a plate-shaped absorber based on a plane reflection unit (see Figure 9 ) is as follows: S1. Obtain the initial design parameters, the number of plane mirrors on one side is 3, the solar photovoltaic panel is located at the lowest end, and the serial numbers of the plane mirrors on one side from bottom to top are 1, 2 and 3, the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel is α1=10°, the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel is L=2mm, the width of the solar photovoltaic panel is W=156mm; the design irradiance of the uniform condenser is 1000W / m 2 ; S2. Based on the initial design parameters, a mathematical model of the geometric relationship of each plane mirror of the uniform condenser is established, and the structure parameters of each plane mirror are calculated; the structure parameters include the angle α n between the lower end point of the nth (n=1, 2 and 3) plane mirror and the surface of the solar photovoltaic panel, the inclination angle β n of the nth plane mirror, and the width D n of the nth plane mirror; When n=1, the mathematical model is: ; In the formula, W is the width of the solar photovoltaic panel, L is the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel, α1 is the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel, β1 is the inclination angle of the first plane mirror, and D1 is the width of the first plane mirror; When n=2, the mathematical model is: ; In the formula, α2 is the angle between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, β2 is the inclination angle of the second plane mirror, and D2 is the width of the second plane mirror; When n=3, the mathematical model is: ; In the formula, α3 is the angle between the lower end point of the third plane mirror and the surface of the solar photovoltaic panel, β3 is the inclination angle of the third plane mirror, and D3 is the width of the third plane mirror; The specific values of the inclination β1 (50°) and the width D1 (42.14 mm) of the first plane mirror are obtained by calculation; meanwhile, the position of the upper end point of the first plane mirror is calculated, the angle α2 (48.31°) between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel is determined, and the inclination β2 (69.16°) of the second plane mirror is calculated according to the angle α2 (48.31°) between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, and D2 is the width D2 (327.38 mm) of the second plane mirror; meanwhile, the position of the upper end point of the second plane mirror is calculated, the angle α3 (66.74°) between the lower end point of the third plane mirror and the surface of the solar photovoltaic panel is determined, and the inclination β3 (78.37°) of the third plane mirror is calculated according to the angle α3 (66.74°) between the lower end point of the third plane mirror and the surface of the solar photovoltaic panel, and D3 is the width D3 (711.08 mm) of the third plane mirror; According to the initial design parameters, the inclination β1 (50°) and the width D1 (42.14 mm) of the first plane mirror, and the angle α2 (48.31°), the inclination β2 (69.16°) and the width D2 (327.38 mm) between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, and the angle α3 (66.74°), the inclination β3 (78.37°) and the width D3 (711.08 mm) between the lower end point of the third plane mirror and the surface of the solar photovoltaic panel, the uniform condenser model is accurately constructed in the three-dimensional modeling software; S3. The light ray tracing software Tracepro is used to perform light ray tracing simulation on the uniform condenser model constructed according to the mathematical model under the condition that the incident angle is 0°, and the landing position of each ray on the absorption surface is recorded (see Figure 10 ); the simulation landing points are compared with the theoretically predicted landing points of the mathematical model point by point, and the root mean square error RMSE (0.73 mm) and the maximum deviation e max (1.21 mm) are calculated; according to the mathematical model reliability determination method, if RMSE≤1 mm and e max ≤2 mm, it is determined that the mathematical model is reliable; otherwise, the parameters such as the inclination of the mirror (allowing adjustment of ±1°) and the width (allowing adjustment of ±2 mm) are adjusted, and recalculation and simulation are performed until the determination condition is met; therefore, the root mean square error RMSE (0.73 mm) of the embodiment is less than 1 mm, and e max (1.21 mm) is less than 2 mm, and the mathematical model is reliable; S4. The light ray tracing software Tracepro is used to perform light ray tracing simulation on the uniform condenser model constructed according to the mathematical model under the condition that the incident angle is 0°, and the landing position of each ray on the absorption surface is recorded (see Figure 11 ); the simulation landing points are compared with the theoretically predicted landing points of the mathematical model point by point, and the root mean square error RMSE (0.73 mm) and the maximum deviation e max (1.21 mm) are calculated; according to the mathematical model reliability determination method, if RMSE≤1 mm and e max ≤2 mm, it is determined that the mathematical model is reliable; otherwise, the parameters such as the inclination of the mirror (allowing adjustment of ±1°) and the width (allowing adjustment of ±2 mm) are adjusted, and recalculation and simulation are performed until the determination condition is met; therefore, the root mean square error RMSE (0.73 mm) of the embodiment is less than 1 mm, and e max (1.21 mm) is less than 2 mm, and the mathematical model is reliable;2 ), and compared with the energy flow density of each point; according to the energy flow density distribution uniformity determination method, if the energy flow density of all regions deviates from the average value by no more than ±10%, it is considered that the energy flow density distribution is uniform; otherwise, the parameters such as the mirror inclination angle (allowing adjustment of ±1°) and the width (allowing adjustment of ±2mm) are adjusted to redesign until the determination condition is met; In this embodiment, the deviation of the energy flow density of all regions from the average value is 5.2%, which is less than the threshold value 10%, so the energy flow density distribution on the absorption surface of this embodiment is uniform.

[0021] The specific embodiments of the application are described in detail above, but the application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application.

Claims

1. A method for designing a homogenizer for a plate-shaped absorber based on a planar reflective unit, characterized in that, The uniform concentrator comprises a solar photovoltaic panel (1) and plane mirrors (2) symmetrically arranged on both sides of the solar photovoltaic panel (1) to uniformly reflect the sunlight incident on the plane mirrors (2) to the entire light-receiving surface of the solar photovoltaic panel (1). The specific steps are as follows: S1. Obtain initial design parameters, the number of single-sided plane mirrors is N, the solar photovoltaic panel is located at the lowest end, the serial numbers of the single-sided nth plane mirror from bottom to top are 1, 2, …, N, the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel is α1, the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel is L, and the width of the solar photovoltaic panel is W; S2. Based on the initial design parameters, a mathematical model of the geometric relationship of each block plane mirror of the uniform concentrator is established, and the structure parameters of each plane mirror are calculated; the structure parameters include the included angle α between the lower end point of the nth plane mirror and the surface of the solar photovoltaic panel n , the inclination angle β of the nth plane mirror n , and the width D of the nth plane mirror n ; S3. Use the light ray tracing software Tracepro to simulate the reflection path and landing point position of the sunlight on the concentrator model constructed according to the mathematical model under the condition of vertical incidence, i.e. an incident angle of 0°, compare the simulated landing point position with the theoretically predicted position according to the mathematical model, and verify the reliability of the mathematical model; S4. Use the light ray tracing software Tracepro to simulate the energy flux density distribution of each region of the solar photovoltaic panel surface under the condition of vertical incidence, i.e. an incident angle of 0°, and verify the uniformity of the energy flux density distribution by analyzing the energy flux density distribution diagram.

2. The method for designing a uniform condenser for a plate-shaped absorber based on a planar reflective unit according to claim 1, characterized in that: The mathematical model in step S2 is: When n=1, the mathematical model is: ； In the formula, W is the width of the solar photovoltaic panel, L is the distance between the lower end point of the first plane mirror and the starting absorption point of the solar photovoltaic panel, α1 is the angle between the lower end point of the first plane mirror and the surface of the solar photovoltaic panel, β1 is the inclination angle of the first plane mirror, and D1 is the width of the first plane mirror; When n=2, the mathematical model is: ； In the formula, α2 is the angle between the lower end point of the second plane mirror and the surface of the solar photovoltaic panel, β2 is the inclination angle of the second plane mirror, and D2 is the width of the second plane mirror; When 3≤n≤N, the mathematical model is: ； In the formula, α n is the angle between the lower end point of the nth flat mirror and the surface of the solar photovoltaic panel, β n is the inclination angle of the nth flat mirror, D n is the width of the nth flat mirror.

3. The method for designing a uniform condenser for a plate-shaped absorber based on a planar reflective unit according to claim 1, characterized in that: The method for verifying the reliability of the mathematical model in step S3 is: In step S3, the light ray tracing software Tracepro is used to perform light ray tracing simulation on the uniform condenser model constructed according to the mathematical model under the condition that the incident angle is 0°, and the landing position of each ray on the absorption surface is recorded; the simulation landing points are compared with the theoretically predicted landing points of the mathematical model point by point, and the root mean square error RMSE and the maximum deviation e max are calculated; if the root mean square error RMSE is less than or equal to 1 mm and the maximum deviation e max is less than or equal to 2 mm, it is determined that the mathematical model is reliable; otherwise, the mirror inclination angle and width parameters are adjusted to recalculate and simulate until the determination condition is met.

4. The method for designing a uniform condenser for a plate-shaped absorber based on a planar reflective unit according to claim 1, characterized in that: The method for verifying the uniformity of the energy flux density distribution in step S4 is: In step S4, the concentrator model constructed according to the mathematical model is simulated in Tracepro under the condition of an incident angle of 0°, the energy flux density distribution on the absorption surface is obtained, the average value of the energy flux density is calculated, and compared with the energy flux density of each point; if the deviation of the energy flux density of all regions from the average value is not more than ±10%, the energy flux density distribution is considered to be uniform; otherwise, the mirror inclination angle and width parameters are adjusted for redesign until the above determination condition is met.

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