Optical performance enhancement in a solar parabolic trough collector with optimized secondary optics

The maximum concentration ratio of the commercial parabolic trough collectors is limited to 42% of the theoretical limit of concentration. Recently, the secondary flat reflector geometry has been proposed to increase the concentration ratio of parabolic trough close to the theoretical limit. Using those secondary reflector geometry as a starting point, we optimize the reflector geometry for commercial LS-3 parabolic trough with additional secondary optics named flat linear refracted Fresnel lens and evaluate the performance using Monte-Carlo ray tracing method. In this paper, theoretical and optical performance analyses of the proposed system have been investigated. The analysis of parabolic trough with additional secondary optics revealed a potential reduction in shadow area of the secondary reflector on the absorber tube and the primary mirror to 0%. It is found that the new concentration ratio of 48.24 was observed for the proposed system, which is nearly 84.19% higher than the commercial LS-3 collector.