Energy, exergy, economic and environmental analyses of solar air heating systems with and without thermal energy storage for sustainable development: A systematic review

Solar air heating is the most widely used for crop drying, building and space heating applications due to its technological maturity and economic viability. Still, solar air heaters (SAHs) have not achieved high performance and development in various applications because of the fluctuating nature of solar energy and the lack of energy storage units. Phase change materials (PCMs) having high energy storage capacity are effectively used to store solar energy as heat during phase change. So, PCMs are primarily used to overcome the above limitation of SAHs and make them more effective and operational during the night/off sunshine hours. The current review article conducts a systematic literature review of recent studies on 4-E (energy, exergy, exergoeconomic, and enviroeconomic) analyses of various SAHs integrated with and without PCMs used for crop drying, building and space heating etc. This study also addresses the performance improvement methods and technical issues related to various SAH systems. As per the results, various modifications were made to the absorber plate along with fins (longitudinal fins, corrugated fins, and baffled fins) to increase the thermal performance of existing SAHs. Generally, SAHs performed better after recycling. Artificially roughened absorbers improve the rate of heat transfer and thermo-hydraulic performance. SAHs using PCMs be more efficient in energy and exergy outputs and have a shorter payback time than SAHs without PCM. Finally, this review article summarizes the efforts made by scientists worldwide to increase the thermal performance of SAHs and provides new insights into the core mechanism of SAHs with and without the use of PCMs.