PASSIVE HEAT TRANSFER ENHANCEMENT TECHNIQUES IN FLAT-PLATE SOLAR COLLECTORS: A COMPREHENSIVE

Abstract

This comprehensive review consistently investigates the techniques of passive enhancement for refining convective heat transfer in flat plate solar collectors (FPSCs) and concentrate on the techniques that persuade swirling flow to deactivate the thermal boundary layer in the flow of the fluids. The main aim is to introduce a structured evaluation of four strategic classifications: geometric modifications on the absorber surfaces, insertion of vortex generators devices, exploitation of Nanofluids and amalgamation of phase change materials (PCMs). This analysis summarizes the results that were obtained from numerical and experimental studies to estimate thermal performance against associated hydraulic compensations. The main results mentioned that V-corrugated absorber surfaces can improved the thermal efficiency by (25%–30%), while the twisted tape inserts upgrade the heat transfer coefficient by up to 70% compared to the smooth tubes nevertheless Nanofluids particularly the Copper oxide/water mixture contributed to an increase in the thermal efficiency approximately (20%). However, these thermal enhancements are consistently escorted by increased pressure drop confirmation of a critical balance in performance. This explanation emphasizes that hybrid systems, such as combining geometric modifications of absorbent surfaces with the use of Nanofluids, offer the most viable solution for improving overall thermos hydrodynamic performance. 

Future research should prioritize the development of such integrated systems, alongside comprehensive economic and lifecycle assessments to ensure practical viability.