Comparative Study of the Performance of Double-Pass and Single-Pass Solar Air Heater with Thermal Storage

The present study aims to increase the heat gain of a solar air heater (SAH) operated at a high mass flow rate of air. The new type of double-pass type solar air heater (DPSAH) is designed and experimented on four consecutive days. The performance of a designed air heater is also compared with a conventional single-pass air heater (SPSAH) having the same geometry. The comparison has been made by considering different heat transfer parameters. The storage is filled in both air heaters to prolong the operation time. The result shows that by increasing the mass flow rate of air, the average efficiency of SPSAH reduced from 35 to 29%, and the efficiency of DPSAH increases from 49 to 61% in peak hours.