Influence of optical errors on the thermal and thermodynamic performance of a solar parabolic trough receiver

Abstract

This paper presents results of an investigation covering the influence of optical errors on the thermal and thermodynamic performance of a solar parabolic trough system. The optical performance was evaluated by using Monte Carlo ray tracing for slope errors and specularity errors in the range 0 to 5 mrad. A parabolic trough collector (PTC) with a rim angle of 80o and a concentration ratio of 86 was considered in this study. The heat flux profiles obtained from the optical analysis were coupled with a computational fluid dynamics tool (ANSYS FLUENT) to numerically investigate the thermal and thermodynamic performance of the receiver. In the numerical analysis, inlet temperatures and Reynolds numbers ranging from 350 K–650 K and 6 800–1 140 000 were considered, respectively. Results show that, slope and specularity errors influence the heat flux distribution on the receiver’s absorber tube. Results further show that the optical performance and thermal performance reduce significantly as the slope errors increase. For the range of parameters considered, the intercept factor reduces by up to 21% while the overall thermal efficiency reduces by up to 17% as optical errors increase. Receiver thermodynamic performance is shown to deteriorate as slope errors increase.