Factors influencing the performance of solar air heater (SAH) having artificial coarseness: a review

Abstract

A review of studies focused on promoting the rate of heat transfer with the help of an optimum rise in friction factor, by offering a simulated irregularity to the interior surface of the absorber plate of SAH, is expressed. In this article an effort has been made to explore different coarseness configurations as used by number of researchers to boost the SAH heat transfer rate. Furthermore, different correlations developed by researchers for Nusselt number and friction factor are also presented. On the basis of these correlations, thermohydraulic performance variable was calculated and attributed for various coarseness configurations. Friction factor and Colburn factor of various coarseness configurations have also been compared and presented. This review focused on use of different coarseness configurations with different coarseness parameter and flow parameter is deeply discussed from which future researchers can easily identify that which coarseness is to be used for designing SAH duct for the better augmentation of heat transfer and friction factor. It also helps the researchers to determine the optimum value of coarseness parameter so that the SAH works efficiently and effectively.