Numerical analysis on the optical geometrical optimization for an axial type impinging solar receiver

Solar cavity receivers are key components in point-focus concentrating solar power technologies due to their benefits of high efficiency and operating temperature. Accordingly, the enhancement of the optical performance can yield to significant improvements in the whole thermal power system. In this study, a geometrical optimization of an axial type impinging receiver for a solar dish Brayton system was analytically accomplished through Monte Carlo ray tracing method. By modeling a reference cylindrical cavity, optical surface properties and geometrical parameters were analyzed by dividing the cavity into three zones: front wall, middle wall and back wall. Simulation results show that the light flux peaking on the cylindrical wall can be significantly reduced when the cavity front wall is modified by changing the inclination angle; the light flux distribution over the absorber surface can be flattened by increasing the cavity radius; the irradiance distribution over the absorber can be efficiently adjusted by modifying the cavity back wall. After the cavity geometry optimization, the optical efficiency of the receiver can be enhanced by 3.34%, the material volume can be reduced by 20.1% and the peak flux on the cavity wall can be reduced by 38.6%, from 30 to 18.4 kW/m(2). (C) 2020 Elsevier Ltd. All rights reserved.