An experimental investigation of performance of a double pass solar air heater with foam aluminum thermal storage medium

Abstract

The enactment of a double pass solar air heater was experimentally probed using four different formations. The scope of present study encompasses the use of Thermal Storage Medium (paraffin wax) integrated with porous/foam metal (aluminum) during the winter season. In the first phase of experimentation, first formation consisted of flat plate whereas foam aluminum embedded with paraffin wax was placed inside two copper ducts in the second configuration. In the third configuration, four copper ducts were used. During the second phase of experiment, similar configurations were used as in the first phase but with pre-heat. No melting of wax was accomplished when the outside air temperature ranged between 12 and 24 °C, however increased thermal conductivity was attained for configuration two and three. Melting of wax was achieved when the outside air temperature ranged between 15 and 29 °C, using pre-heat. The increase in thermal conductivity was achieved using foam aluminum but at the expense of slight decrease in storage capacity of the paraffin wax. In the last configuration no fan was used during the day time, and melting of wax achieved under similar conditions. Fourth configuration provided beneficial heat for 2.5 h after the sunset while the second and third configurations provided expedient heat for 1.5 h after the sunset.