Exergy analysis of parabolic trough solar receiver

This paper presents an exergy analysis to study the effects of operational and environmental parameters on the performance of Parabolic Trough Collectors. The exergy analysis is based on a previous heat transfer model published by the authors. The main parameters considered for the analysis are: inlet temperature and mass flow rate of heat transfer fluid, wind speed, pressure or vacuum in annulus and solar irradiance. The results showed that inlet temperature of heat transfer fluid, solar irradiance, and vacuum in annulus have a significant effect on the thermal and exergetic performance, but the effect of wind speed and mass flow rate of heat transfer fluid is negligible. It was obtained that inlet temperature of heat transfer fluid cannot be optimized to achieve simultaneously maximum thermal and exergetic efficiency because they exhibit opposite trends. Finally, it was found that the highest exergy destruction is due to the heat transfer between the sun and the absorber while for exergy losses is due to optical error. (C) 2014 Elsevier Ltd. All rights reserved.