Experimental Study of Single-Pass Fluid Flow With Convective and Sensible Thermal Energy Storage in a Porous Curved Channel Solar Air Heater

Abstract

In this experimental research, a single-pass solar air heater comprising a porous curved channel is investigated to reveal the scope of high thermal performance during the winter season. The investigation explores the geometrical parameters for the porous channel maintained by using steel wiremesh layers of wire diameter of 0.45 mm and pitch of 2.35 mm, and the number of layers ranging from 3 to 12, which presents the channel porosity, $\varphi$, from 99% to 96%, respectively. The curved porous channel offers additional fluid mixing, thermal backup, and high heat transfer area, thereby increasing the convective heat transfer to the air and consequently the thermal performance. A series of experiments were carried out under real outdoor conditions to examine the various factors such as variable channel porosity, air flow rate, and the amount of solar energy received. The findings revealed that the curved porous channel with a channel porosity of 96% results in the maximum thermal and thermohydraulic efficiencies of about 85% and 79%, respectively, and the outlet air temperature of 79°C.