Performance Enhancement of Parabolic Trough Collector with Oblique Delta-Winglet Twisted-Tape Inserts

Abstract

The aim of this study is to analytically investigate the performance of parabolic trough collector (PTC) with oblique delta-winglet twisted tape insert in the absorber tube. The heat transfer equations for fully developed flow under quasi-steady state conditions have been developed in order to analyse entropy generation, exergy efficiency, thermal efficiency, rise in fluid temperature and to study the effect of system and operating parameters on performance. A computer program, based on mathematical models is developed in C⁺⁺ language to estimate the temperature rise of fluid for evaluation of performances under specified conditions. For numerical simulations four different twist ratio, x = 1,2,3,4 and mass flow rate 0.06 kg/s to 0.16 kg/s (3000≤Re≤9000) are used. This study shows that twisted tape insert when used shows great promise for enhancing the performance of PTC. Results show that for x=1, Nusselt number/heat transfer coefficient is found to be 3.24 and 2.91 times over plain absorber of PTC at mass flow rate of 0.06 kg/s and 0.16 kg/s, respectively; while corresponding enhancement in thermal efficiency is 12.05% and 4.95%, respectively. Also, the exergy efficiency has been found to be 12.05% and 4.92% and enhancement factor is 1.121 and 1.049 for same set of conditions.