Experimental investigation and multi objective optimization of thermal-hydraulic performance in a solar heat collector

The air impinging normally through the jets over the heat transmitting surface prevents the development of boundary layer in its vicinity to a large extent. The variation in system control factors such as diameter of jet, streamwising and spanwising pitch have significant effect on the performance defining attributes of a rectangular channel forced convection fluid flow. An experimental investigation is performed to study the results outcome by alteration of the control factors on performance defining attributes based upon which multi attribute decision making approach (MADM) has been proposed for optimal combination of control factors. The performance defining attributes present a desperate trend in view of which it becomes imperative to optimize the control factors for maximum utility attribute (s) and minimum regret value of the undesired attribute (s) with simultaneous consideration of all. The hybrid analytical hierarchy process (AHP) and preference ranking organization method for enrichment evaluations (PROMETHEE) technique have been processed to meet the desired target. It has been observed that the jet diameter ratio: 0.065, streamwising pitch ratio: 0.435, spanwising pitch ratio: 0.869 and Reynolds number: 16000 is the best combination of control factors among all others to deliver the highest overall performance with same energy input in each case.