Exergy and thermal performance analysis of solar air heater with novel hybrid tape vortex generators for rural applications

Abstract

Its sustainability, affordability, and environmental compatibility are helping solar energy to attract more worldwide interest. Driving industrial progress and helping economic growth in many areas depend much on it. Among the many solar thermal technologies, Solar Air Heaters (SAHs) are particularly important since they have several uses including agricultural drying, space heating, and seawater desalination. But, because of the bad heat transfer qualities of air, which serves as the working fluid, traditional SAHs frequently have low thermal efficiency. The goal of this work is to improve the thermohydraulic capacity of SAHs by means of innovative and novel hybrid turbulator tape inserts in order to solve this issue. These inserts are meant to create more turbulence and secondary flow, therefore improving heat transfer while keeping reasonable pressure losses. With air as the working medium, circular tube uniformly heated under constant heat flux was used for experimental studies. Covering full turbulent flow regimes, the performance was examined over the Reynolds number (Re) fluctuated between 10,794 and 73,644. The findings show an extraordinary 89% increase in Nusselt number (Nu), suggesting much better convective heat transfer (HT). At the same time, a modest 35% rise in friction factor (f) was noted, suggesting a nice balance between losing pressure and improving heat transfer. These results highlight the possibility of hybrid tape inserts as a quick passive method to increase the thermal performance of SAHs, therefore providing interesting consequences for energy-efficient solar thermal systems. The novelty of this investigation is the experimental implementation of a hybrid wavy with spring inserts of tape type, which delivers increased secondary flows and augmented convective heat transfer. In contrast to conventional inserts, the hybrid design can achieve significant enhancements in thermal and exergy performance with lower pressure penalties. As a consequence, this novel shape observed an impressive 89% growth in the Nusselt number (Nu), and it could be very useful for a real life engineering applications pertaining to energy conversion systems in rural area.