Abstract: Concentrating solar power tower has the problem that the heliostats have low precision shapes and large spot, which limits the system conversion efficiency and cost. Regarding this problem, firstly, the ideal heliostat shape model is built based on optical analysis. A compliant mechanism is proposed based on the plate bending theory. Different from the conventional mirror design with uniformly distributed stiffness profile, the proposed design tailored the two-dimensional stiffness of a square plate, which permitted to use couples of simple, low-cost bending moments to form the required heliostat shape. Numerical analysis is conducted including finite element analysis, optical ray-tracing, and Newton optimization. A heliostat prototype experimental system is designed and built. The simulation and experiment results show that the shape implemented by the proposed mechanism can reduce the spot size with a higher efficiency than the flat mirror. The proposed simple, low-cost mechanism provides a reference methodology for the practical system.

Key words: Clean energy, Concentrating solar power, Heliostat, Plate bending mechanism, Stiffness design