Performance evaluation of an arched plate solar air heater with porous aluminum wire mesh cylindrical fins

Abstract

Solar air heater is used to heat air for space heating and drying process, but its low heat transfers between absorber plate and air account for its low thermal performance. Various surface geometries and fin modifications in a solar air heater have improved its thermal performance. The fabrication and performance evaluation of a solar air heater with an arched wavy absorber plate having porous aluminum wire mesh cylindrical fins attached have been investigated. The arched absorber plate design resulted in an increase in the air turbulence and vortex generation, which leads to the breaking of laminar sub-layer near the surface of the absorber plate and improved the heat transfer. In addition, cylindrical porous wire mesh aluminum fins resulted in an increase in the fin porosity which reduces the pressure drop and improved the thermal performance of the solar air heater. Comparative analysis has been carried for different arrangements at three different fluid flow velocities. The arched wavy absorber plate with fins resulted in better thermal performance with a temperature difference in the range of 55–70 °C approx. compared to the other arrangements at a fluid flow velocity of 5 m/s.