Optimized design of a linear Fresnel collector with a compound parabolic secondary reflector

Abstract

In linear Fresnel collectors (LFCs), a receiver composed of CPC secondary reflector and evacuated tube need to be highly coupled with the mirror field. An optimized design method of the LFC is proposed in this paper. Firstly, a mathematical model of the CPC for the LFC is established, with the effects of the choice of half-acceptance angle and truncation ratio on the geometrical optics efficiency of the CPC studied by using the ray tracing method according to the characteristics of the LFC. Secondly, a method for designing the mirror field without shading is presented by using the half-acceptance angle of the CPC to limit its height-width ratio. Finally, a scheme for designing the mirror field is proposed, considering the ground utilization ratio and the mean shading and blocking efficiency. The results indicate that the optimized CPC at half-acceptance angle 50° and truncation ratio 0.4 for the LFC can achieve the geometrical optics efficiency of 84.52%. The designed mirror field can achieve the ground utilization ratio of 73.08% and the mean shading and blocking efficiency of 97.56%.