Wind load design considerations for the elevation and azimuth drives of a heliostat

Abstract

This paper investigated the dynamic fluctuations of the high-frequency surface pressure and force measurements on an instrumented scale-model heliostat within a turbulent ABL generated in a wind tunnel. Peak aerodynamic load coefficients on the model heliostat calculated following the equivalent static wind load method were consistent with previous wind tunnel studies in the literature. The dynamic analysis of the hinge, azimuth and overturning moments in the current study showed that there are a range of critical load cases and heliostat configurations that need to be considered to investigate the dynamic loading on the elevation and azimuth drives of a heliostat. Quasi-steady variation of the fluctuating peak loads following a Gaussian distribution was found to under-predict the maximum hinge and overturning moments in operating and stow configurations. It is therefore recommended that the analysis of instantaneous loads on the elevation drive and pedestal foundation is carried out for an improved estimation of the heliostat design wind loads.