Optimal Design And Optical Performance Research Based On Cassegrain Solar Line Concentrator

As an inexhaustible,green and pollution-free new energy source,solar energy has many advantages such as environmental protection and renewable energy,and has attracted much attention.In the context of"carbon peak"and"carbon neutrality",the utilization of solar energy resources has become a global research and development hotspot.The full development and utilization of solar energy resources is one of the important technical ways to achieve the dual-carbon goal.The full development and utilization of solar energy resources is one of the important technical ways to achieve carbon emission targets.Improving the efficiency of solar energy systems and reducing the cost of acquiring solar energy resources are prerequisites for large-scale development and utilization of solar energy resources.Under the existing technical conditions,the development of efficient and reliable solar concentrators is an important technical measure to reduce the acquisition of solar resources.In the design of the solar thermal concentrator system,the intercept factor and optical efficiency calculation are the key issues in the design of the solar concentrator.Based on the research of improving and optimizing the geometric concentration ratio in solar concentrating design,this thesis,based on the Cassegrain optical structure,carried out related theoretical derivation and numerical simulation on the optimal design of solar secondary reflection concentrating-heat utilization The research aims to develop a high-efficiency,economical,practical,and reliable high-concentration photovoltaic system with a concentration ratio of more than 200 through the optimization design and optical performance of the system.The main research contents include:（1）Based on the technical defects of the currently widely used trough concentrator,a multi-purpose concentrator based on the principle of the Cassegrain astronomical telescope is constructed;Based on the theory of conic section and optical principles,a functional relationship between the effective geometric concentration ratio of the Cassegrain line of different structures and the geometric characteristics of the system is established;Developed a practical and reliable algorithm to calculate the effective geometric concentration ratio of the Cassegrain solar line concentrator system with different structures such as plane,hyperbola,ellipse and parabola with secondary reflection;（2）Based on the design principle of the ideal concentrator and the transmission process of the edge light,the numerical calculation model of the geometric concentration ratio and focal plane position（absorber）of Cassegrain line concentrators with different structures was established;（3）With the help of numerical calculation technology,the structural parameters of different concentrators have been studied in depth,and their influence on the concentrating ratio and optical performance,and the optimization design of various concentrators with the maximum concentrating ratio as the optimization goal is analyzed.;Based on the solar geometry and the principle of edge ray,the concentrating system model of Cassegrain line concentrators with different structures is established.Taking into account the half angle of the solar light source,through theoretical derivation,numerical simulation and comparison,the optimal combination theory is adopted.The variable loop optimization method has found the secondary reflection system with the best Casegrain structure;（4）Based on solar geometry and optical principles,the optimization model of solar energy concentration performance of Cassegrain,compound parabolic concentrator（CPC）and compound elliptical concentrator（CEC）was constructed,and the different parameter conditions of Cassegrain,CEC and CPC were compared.Research shows that the geometric concentration ratio of CEC is higher than that of CPC,and the best geometric concentration ratio of CEC is 210.3795;（5）Adopting numerical calculation and Python language programming method,through analyzing the complex calculation expression of interception factor,combined with optical reality,a method based on numerical calculation+Python programming is proposed,which simplifies the calculation of interception factor and develops interception factor The calculation system provides a reference for the actual project.The research results show that when the tracking error is greater than 0°,the interception factor decreases with the increase of the tracking error,random error and installation error.The effective range for calculating the approximate value of the interception factor is[-1.5×10^-7,1.5×10^-7];（6）In view of the situation that errors are prone to occur in the solar installation process,the research on the installation error of the secondary reflection surface and the absorber of the hyperboloid secondary reflection system is carried out,and the relationship between the secondary reflection hyperboloid and the absorber is explored.The research results show that the installation error of the planar absorber is lower than that of the double reflection hyperboloid;the downward installation error of the planar absorber is lower than the upward installation Error;the downward installation error of the secondary reflection hyperboloid is lower than the upward installation error;（7）The correlation between the optimized system structure parameters and the concentration ratio is obtained by machine learning analysis method;through the machine learning method,the solar energy concentration performance prediction model of Cassegrain,CPC and CEC is constructed,revealing Cassegrain,CEC And the relationship between CPC and various parameters,the effective geometric concentration ratio based on Cassegrain,CPC and CEC and the analytical expressions between related parameters are obtained,and the concentration ratio of secondary reflection hyperboloid Cassegrain,CPC and CEC is established.The functional relationship with each parameter.