Research On Performance Optimization Of Secondary Reflection Tower Solar Power System

Traditional thermal power generation methods need to be transformed to meet the requirements of modern society for environmental protection and sustainable development.Solar energy is an inexhaustible source of clean energy and the prospects for its development is broad.At present,there are mainly two methods of solar power generation:photovoltaic power generation and solar thermal power generation.Among the solar thermal power generation technologies,solar tower power generation has advantages in large-scale applications.In traditional solar tower power system,the receiver is set atop a high tower.The risks in installation and maintenance are high besides the poor economy.In the tower reflector system,a reflective mirror is mounted on the reflective tower and sunlight reflected from the heliostat is reflected to the receiver located on the ground by the reflector.Because of the tower reflector,the shortcomings of traditional solar tower power system have been made up.The layout of the heliostat field and the shape of the reflective mirror are studied,as well as error correction of the tower reflector system.On this basis,the heliostat field is optimized to provide a theoretical basis for the economics of the solar power plant.Main works are as follows:First of all,the trajectory of the sun is studied.In the case of determining the solar coordinate system,a sun position algorithm is used to calculate elevation and azimuth angle.The model of solar motion is established,and some simulations of solar trajectory at vernal equinox,summer solstice,autumnal equinox,and winter solstice are carried for further research.Secondly,model of the tower reflector system is put forward.According to the general design method of heliostat field,the shape of the heliostat and the layout of the heliostat field are determined.Based on establishment of mathematical models of different types of secondary reflective mirrors,the relationship between the size of the secondary reflective mirror and the layout of heliostat field is studied for further study of the efficiency of whole system.Thirdly,the optical efficiency model of the tower reflector system is offered.The cosine efficiency of the tower reflector system is studied in depth because of thesignificance,and the system is optimized based on the characteristics of the cosine efficiency.Finally,the error composition of the tower reflector system is analyzed,and the error calibration method is introduced in detail according to the cause of the error formation.Through deducing correction process,the calibration model of the secondary reflective mirror is set up,and then simulation is performed.The study of errors has a positive effect on the performance optimization of the entire tower reflector system.To sum up,a model of a tower reflector solar power system is built,and the characteristics of the cosine efficiency of the whole system is studied with proposition of a correction method for the tower reflector solar power system.A theoretical basis for the development of tower reflector solar power system is provided by optimizations for the performance of the system.