Optimization Of Solar Thermal Power Tower Mirror Field Research And Simulation

With the rising international oil prices and the worsening global climate, the development and utilization of solar energy has been paid more and more attention. Concentrating Solar Power (CSP) is an important technology to develop and utilize solar energy on a large-scale. Solar power tower is the first choice to achieve large capacity grid-connected power generation with its incomparable advantages. However, the researches on CSP are still at the primary stage of development and demonstration in China and high cost is the key problem limiting its development. This thesis mainly focuses on distribution of heliostats field, the scheduling method of heliostats field and the ground coverage of heliostats field, and detail works are as follows.Firstly, the sun motion model of horizontal coordinate system and vector coordinate system are established to calculate the sun angles throughout a whole day. Variation rule of the sun angles is summarized.Secondly, radical staggered configuration is designed as an optimal field layout. The model of cosine efficiency is established to simulate the sun incident angles and cosine efficiency. Variation rule of the sun angles is summarized, and distribution range of cosine efficiency is obtained. Furthermore, the relationship between the height of tower and the average cosine efficiency is researched.Thirdly, a scheduling model is established by considering direct normal irradiance, reflectance of heliostat, cosine efficiency, and atmospheric transmittance factors. The scheduling model can be described as a0-1knapsack problem. This problem is resolved with greedy algorithm which is combined with standard particle swarm optimization (SPSO) and hybrid genetic algorithm (HGA) respectively. From the simulation results, the number and the distribution diagram of heliostats are obtained when the conversion efficiency of system is optimal. Furthermore, subsection scheduling strategy is propounded.Lastly, through the comparison and analysis of the various shapes heliostats, the ground coverage models are established in different situations. One situation is only considering the factor of colliding neighboring reflectors. The other situation is considering blocking factor in heliostats field. Maximum ground coverage can be obtained from the simulation results based on the size of heliostats when width-height ratio of reflectors meets necessary condition.This thesis presents methods of optimizing heliostats field of solar power tower system. The research results provide theoretical foundations for reducing the system cost of power generation and improving the system concentrating efficiency in the solar power tower.