Stowing strategy for a heliostat field based on wind speed and direction

Abstract

This paper investigates a stowing strategy of a heliostat field based on wind speed and direction, in terms of the potential benefit of additional energy collection through the partial stowing of heliostats within an azimuth angle range with reduced operating wind loads. Correlations of one-minute wind speed and DNI at a heliostat field site with the operating wind loads, based on the azimuth-elevation tracking angles of individual heliostats, were used to assess the increased operating time and collected thermal energy by the field. The results show that more than 23% of heliostats in the sector of the field with operating wind loads that are smaller than 50% of the stow loads can continue to operate during a high-wind period (e.g. 10 m/s). Adopting a stow strategy based on wind direction can increase the annual operating time of the heliostat field by 6% with increasing stow design wind speed from 6 m/s to 12 m/s. Furthermore, the stowing strategy based on wind direction to allow heliostats to continue to operate at wind speeds exceeding 10 m/s can achieve an additional 280 MWh of thermal energy collected by the heliostat field operation during time periods that would conventionally stow the entire field with 24 GWh of annual thermal energy captured.