Aiming strategy model based on allowable flux densities for molten salt central receivers

Abstract

Abstract This study presents an aiming model to properly point heliostats at cylindrical molten salt receivers in Solar Power Tower. By means of two iterative algorithms (search and fit), the proposed strategy attempts to maximize the receiver thermal power output while preserving the receiver operational limits. Corrosion and thermal stress constraints are translated into allowable flux densities ( AFD ) that are handled by the model. The computer code accommodates the flux images produced by each heliostat in a field to accurately fit the AFD limit. In this paper, a Gemasolar-like field–receiver system serves to illustrate the aiming model. Compared to the equatorial aiming, receiver interception is slightly lower using the proposed strategy, but the receiver integrity is ensured; peak flux is significantly reduced up to 23%. It has been found that a favorable flux density profile generally has its peak displaced to the salt entrance at each receiver panel. Since external cylindrical receivers consist of a combination of up-flow and down-flow panels, the optimal flux profile is challenging for contiguous panels with contrary demands. In spite of that, remarkable matching is achieved by the fit algorithm. Because of its fast computation and automatic operation, the resulting tool can be applied to real-time control of existing heliostat fields and the integrated design of the coupled systems field and receiver.