Ray tracing analysis of linear Fresnel concentrators and the effect of plant azimuth on their optical efficiency

Abstract

Although for a quite small number of installations, Linear Fresnel Collectors (LFC) represent an interesting technology for efficient solar energy exploitation at medium to high temperatures thanks to their lowest land area per electric power ratio if compared to other available CSP solutions. The first prototypes were realized in the ‘60 by Professor Giovanni Francia at the University of Genova, Italy. In this research, 3D ray tracing simulations are performed employing the proprietary, literature-validated code FresnelSim. This in-house developed algorithm, which models the effect of shading, blocking and end effects based on the plant geometrical parameters, has been implemented to efficiently describe plants whose axis is oriented differently than north-south, as it is often assumed. Based on different optical efficiency definitions and real plant dimensions and parameters, a parametric analysis is here presented to investigate the effect of the plant orientation on its performance. The energy available at the receiver results to be reduced by 8.7% on a yearly basis when the system is oriented east-west instead of north-south; on the other hand, it has been observed that higher winter peak efficiencies and a more constant yearly production are achieved when the system is rotated with respect to the reference alignment.