Experimental Investigation and Optimizing the Parameters of a Solar Air Heater Having Broken Arc-Shaped Ribs Using Hybrid Entropy-VIKOR Technique

Abstract

In this article, thermal performance of a solar air heater (SAH) having broken arc-shaped ribs has been investigated experimentally, and then, performance parameters have been optimized. Study reveals that the use of artificial roughness enhances both heat transfer rate and pumping power requirement, and hence, the overall performance of solar air heater increases. Thus, it is imperative to optimize the performance-defining criteria viz. Nusselt number enhancement ratio, friction factor enhancement ratio, and thermohydraulic performance parameter, to propose an optimal set of flow and roughness parameters. The hybrid entropy-VIKOR technique has been employed to outline the optimal set of parameters using performance-defining criterions, to obtain maximum profit with the minimum incurred cost. The optimal set of parameters attained using entropy-VIKOR approach among all the alternatives is as follows: relative gap width = 4, relative roughness pitch = 10, and arc angle = 45 deg at Reynolds number = 9000.