Experimental Investigation on Performance of a Double Pass Solar Air Heater Using Black Coated Porous Wire Mesh as Packed Bed in Rajshahi Division

Abstract

In this experimental study, a double pass Solar Air Heater (SAH) utilizing black coated porous wire mesh as a packed bed was subjected to rigorous analysis. The research focused on assessing the system's performance using efficiency as a key metric, while also considering the temperature differential between the inlet airflow at ambient conditions and outlet airflows. Throughout the investigation, solar intensity was continuously monitored over a day to gauge the availability of solar energy at the experimental location, demonstrating satisfactory levels. Additionally, the heat-absorbing characteristics of the packed bed were scrutinized under three distinct flow rates (0.0115 kg/s, 0.028 kg/s, and 0.038 kg/s). The findings demonstrated that with an increase in flow rate, the temperature difference between the incoming and outgoing airflows exhibited a decrease. Nevertheless, this was accompanied by a noteworthy enhancement in overall system efficiency. Notably, the maximum efficiency exhibited a substantial improvement with increasing flow rate, reaching an impressive gain of 120% to 150%. Moreover, the performance of the solar collector exhibited a characteristic trend of increasing to decreasing throughout the whole day, corresponding to the varying solar intensity levels.