Optimization of a discrete dish concentrator for uniform flux distribution on the cavity receiver of solar concentrator system

In this paper, a novel discrete solar dish concentrator (DSDC) and its optimization method are proposed for improving the flux uniformity of the absorber surface inside cavity receiver. The creation of DSDC generatrix is very simple by dividing an ideal parabolic generatrix into several parts and rotating each part around its one end. The mirror equation, spot radius and optimization model of DSDC are established and an integrated approach coupling the ray tracing method and genetic algorithm is applied to optimize the DSDC to homogenize the flux distribution on absorber surface. A program in C++ is developed for performing the above functions and its correctness is verified by literature. Then, a cylindrical cavity receiver is used to verify the validity of proposed method. The results show that the optimized DSDC not only significantly improving the flux uniformity of absorber surface, i.e., the non uniformity factor is reduced from 0.55 to 0.63 (using parabolic concentrator) to 0.10-0.22, but also reducing the peak flux and maintaining the excellent optical efficiency between 88.93% and 92.19%. Finally, the application of optimized DSDC in photovoltaic, thermoelectric generation and heat utilization are discussed and flux homogenization effect of optimized DSDC on cylindrical cavity receiver with metal tubes is analyzed. (C) 2018 Elsevier Ltd. All rights reserved.