Design and performance analysis of a multi-reflection heliostat field in solar power tower system

This paper proposes a multi-reflection heliostat to improve solar power tower plant performance. It can eliminate the significant cosine loss by keeping its aperture always facing the sun. The key structural parameters are specially designed for a superior solar image property. On its basis, a case study on the three-reflection heliostat is first conducted. By the field efficiency distribution comparison between the two types of heliostats, the multi-reflection heliostat is found to have an efficiency advantage in central region. Then in reference to the original Gemasolar field, the three-reflection heliostat field is generated by the proposed layout method. Its optical efficiency is 5.56% higher and the land area is 68.31% smaller, compared to the performance of the optimized Gemasolar field. For the purpose of practical application, the heliostat with ganged multi-reflection modules is developed. The occupied land area of its field is 51.28% less than that of the latter one. The prototype of five-reflection heliostat is developed for a further performance validation. In the outdoor test, the solar concentrating performance agrees well with the simulation result.