A Numerical Analysis of Baffled Solar Air Heater

Solar energy is one of the most important renewable energies utilized in numerous applications. The present work focuses on numerical analysis of a solar air heater (SAH). The main challenge in SAH is to improve the temperature of the air keeping the absorber plate temperature within the limiting range. It can be achieved with the addition of fins or baffles at the cost of pressure loss. In the present work, the effect of conducting baffles on the thermos-hydraulic performance of SAH is studied. A constant heat flux (1110 W/m2) is applied on the absorber plate. Average Nu and the frictional pressure drop across the solar air heater are comprehensively investigated using the commercial software of Ansys Fluent. The baffle height and number of baffles are varied in the range of 0 to 0.03 m and 0 to 33. The air flow in SAH is considered in turbulence range with Reynolds number varying from 4000 to 16,000. It is observed that Nu becomes maximum at nine baffles at a baffle width and height of 0.06 and 0.02 m for both Re of 8000 and 16,000. The pressure drop follows the same trend of Nu and becomes maximum at nine baffles.