Field test research and design of a new-type heliostat support structure in coarse gravel

Abstract

A solar power tower plant includes a solar tower and tens of thousands of heliostats, where the latter accounts for 40–50% of the total cost. To reduce heliostat costs, a new type of heliostat support structure that consists of a pre-stressed high-strength concrete (PHC) pipe pile and cast-in-place concrete is proposed. However, the performance and applicability of this structure are unknown. Thus, this paper reports full-scale field load testing of the proposed heliostat support structure on coarse gravel as subject to lateral loads or torsion-lateral combined loads. The results indicate that the lateral load amplifies the rotation under torque, and the proposed support structure for mirror arrays can provide sufficient rigidity to limit structural deformations within tolerable values under severe wind loading. Together with 3D modeling, the performance of the proposed heliostat support structure is thoroughly investigated to facilitate the development of modified prediction methods for its lateral and torsional load responses. A detailed design procedure is proposed for the new structure that considers foundation deformations, bearing capacity, and survival requirements. Finally, this study proves the applicability of the proposed heliostat support structure to improve the economic performance of solar power tower plants.