Twisted Tape Based Heat Transfer Enhancement in Parabolic Trough Concentrator - An Experimental study

The heat transfer augmentation in parabolic trough concentrator is gaining importance now a days as it makes the system compact and efficient. Out of various techniques, use of twisted tape inserts is popular due to easy implementation as well as substantial enhancement in system performance. Most of the studies in this field pertaining to experimental/computational analysis with respect to both outdoor and indoor set ups. The rise in convective coefficient of heat transfer fluid due to insert has been studied by many researchers. But such studies are based on uniform heat flux or out-field non-uniform based which is under uncontrollable environment. Hence in the present study, Nusselt number correlations for plain absorber and absorber with twisted tape (y=3.48, 5.42 and 7.36) are developed under the realistic condition of solar concentration with controlled environment. The parity plot shows the maximum deviation of 20% which in turn indicates better quality of fit.