Post-Installation Heliostat Field Aiming Strategy Optimization Based on Heliostat Flux Distribution Measurements

Optical properties of the heliostats installed in central receiver power systems are sometimes different from the design specification to various extent, impacting mostly the reflecting surface curvatures and normal directions. For large area heliostats or heliostats close to the central receiver, such deviations may result in substantial degradation of heliostat field optical performance and cannot be corrected easily. This paper proposed an efficient and systematic approach to account for heliostat optical parameter deviations by post-installation heliostat flux distribution measurements and optical models to obtain effective focal length and orientation angles of each heliostats as an equivalent simulation model for more accurate description for the optical performance. The parameter identification is formulated as an optimization problem solved by genetic algorithm minimizing the difference of each flux value between the calculated flux distribution obtained by Solstice tool and the measured flux distribution analyzed by photographed spot image. The heliostat field aiming strategy is optimized based on those identified effective parameters. The experiment results showed the optimized aiming strategy based on identified parameters yeilded better performance than that with designed parameters.