Experimental investigation on the performance of an impinging jet solar air heater

Investigation on an impinging jet solar air heater is performed and reported in this work. The air is supplied through an impinging jet pipe which contains the nozzles to distribute the air in the solar air heater. The air is released from the jet strikes the absorber plate which increases the heat transfer rate by creating turbulent flow in the collector. This study is focused on the parameters that affect the heat transfer characteristics and compared with conventional solar air heater. The system is examined by varying the angle of attack (0 degrees, 10 degrees, 20 degrees, 30 degrees, 60 degrees and 90 degrees) and the nozzle diameter (3 mm, 5 mm and 7 mm) in the air mass flow rate range of 0.012-0.016 kg/s. The study revealed that the highest performance is achieved with the 30 degrees angle of attack, and the lowest performance is recorded with the 0 degrees. The reduction in jet diameter increases the pressure loss in the collector. The better system performance is observed with the 5 mm diameter hole. The maximum thermal enhancement factor of 2.19 and efficiency of 55.8% are reached with the flow rate of 0.016 kg/s. (C) 2016 Faculty of Engineering, Alexandria University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).