Evaluation of Thermal Performance Factor of Novel Two-Pass, Ribbed, U-Shaped Channel for Solar Air Heater

Solar is a clean, convenient, sustainable, safe, abundant and economical source of energy. Solar Air Heater (SAH) is widely used in solar energy applications. In the current study, an attempt is made to increase the efficiency of SAH. A novel ribbed double pass U-shaped channel with a sharp turn is used as the channel of absorbing plate. Two ribs are implemented on the inlet and middle of the turn part of two-pass channel. The study of thermo-hydraulic performance inside the sharp part for two ribs at the inlet and middle of the outer wall are studied at pitch ratio and the rib height-to-hydraulic diameter ratio (e/D
h
) of 13.5 and 0.1 respectivelly and Reynolds number of 20,000. All the cases are compared based on a smooth channel. It is observed that friction factor decreases by 42%, Nusselt number increases by 1.96% and thermo-hydraulic performance index increases by 20% as compared to the smooth channel.