Experimental investigation and optimization of impinging jet solar thermal collector by Taguchi method

In this paper, an experimental investigation has been carried out to study the influence of geometrical variations of impinging air jets on heat transfer and fluid friction in a solar thermal collector. Taguchi based design of experiment approach has been applied to optimize the parameters which is apposite for an optimal design towards efficient energy conversion. In total sixteen experimental runs have been performed on three main control factors viz. jet diameter ratio, streamwise and spanwise pitch ratio each having three levels of operation. The heat transfer and fluid friction behaviour have been studied along with the thermohydraulic performance in terms of performance index which plays simultaneously both these criteria. The results show that the geometric variations significantly affect the performance of impinging jet solar thermal collector. The investigation reveals that the jet diameter ratio contributes the most towards overall performance with contribution ratio of 48.86% followed by spanwise pitch ratio and streamwise pitch ratio with contribution ratio of 41.61% and 9.53% respectively. Finally, an optimal design combination of an impinging jet solar thermal collector has been obtained with an improvement of 37-48.3% at Reynolds number in the range 4000-16,000. (C) 2017 Published by Elsevier Ltd.