Reducing Optical Losses in Parabolic Trough Collector Solar Fields

Abstract

Geometric manipulations of solar field layout and parabolic trough collector design in concentrating solar power plants are suggested to maximize heat collection and minimize optical losses. Explicitly, two simple adjustments are proposed to maximize incident solar radiation collection and to minimize reflected solar radiation end loss. One adjustment involves altering the orientation angle of the solar field from the conventional north–south alignment to a more polar alignment. The other adjustment consists of deliberately misaligning the parabolic trough collector from its absorber in the axial direction by a predetermined amount. The solar field orientation angle and the extent of the parabolic trough collector misalignment were optimized to minimize optical losses based on typical meteorological year weather data for the eight locations. An Operations Research tool was employed to find the ideal solar field orientation angle and the ideal extent of parabolic trough collector misalignment at each location that will result in maximum incident solar radiation. A validated performance model of a concentrating solar power plant was then used to evaluate gains realized by the suggested adjustments at each location. The gains realized by altering the orientation angle of the solar field were quite significant, while the gains realized by deliberately misaligning the parabolic trough collector from its absorber were much more modest. The cost associated with implementing both proposed adjustments is expected to be minimum since no significant structural changes are involved.