Numerical investigation of the effect of slope errors and specularity errors on the thermal performance of a solar parabolic trough collector system

Abstract

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.The optical efficiency of a parabolic trough collector is one of the most important parameters that affect the performance of the entire collector system. In this study, an optical and thermal analysis of a parabolic trough collector system for different slope errors and specularity errors is presented. For optical analysis, the influence of slope errors, specularity errors and system geometry on heat flux distribution on the receiver's absorber tube is determined using Monte-Carlo ray tracing in SolTrace. The ray tracing results are then coupled with a computational fluid dynamics code to investigate the thermal performance of the receiver. Results show that the slope and specularity errors influence the heat flux distribution on the receiver's absorber tube. The optical efficiency of the collector is shown to reduce significantly as the slope errors increase and slightly as specularity errors increase. The influence of slope errors and specularity errors on the thermal performance of the entire system is investigated numerically and presented.