Secondary concentrator optimization of a linear Fresnel reflector using Bezier polynomial parametrization

Abstract

Linear Fresnel reflector (LFR) consists a promising solar concentrating technology for medium and high temperatures (150–400 °C). Usually, these collectors are designed with a secondary reflector in order to maximize the exploitation of the incident solar irradiation. The objective of this work is to optimize the secondary reflector of an LFR using Bezier polynomial parametrization which is something new in this domain. This parametrization is based on the movement of some control points (three in this case) in order to determine the optimum secondary reflector geometry. According to the final results, the optimum optical efficiency of the LFR is found to be 72.84%, while the optical efficiency in the initial design is 61.01%. Moreover, the optical efficiency is calculated for different solar angles and it is found that the optimized concentrator has superior performance compared to the initial design in all the cases. Furthermore, it is found that the optimum design leads to a relatively uniform heat flux distribution over the absorber periphery compared to the initial design. The last step is the determination of the thermal efficiency performance curve and it is found 20.50% mean thermal efficiency enhancement with the optimum design.