Numerical Study of Flat Plate Solar Air Heaters With and Without Fins

Solar air heaters are devices which utilize absorbed solar energy by transferring heat to the air passing through air channels. Present study investigates the performance enhancement of a conventional solar air heater by assigning rectangular fins to the bottom plate. The impact of the assigned fins are examined by comparing the finned flat plate solar air heater with a standard flat plate solar air heater without fins, over a relevant range of air mass flow rate and solar irradiance values. The mathematical model built is numerically solved on MATLAB-R2020b. The results indicate that installation of fins boosts the performance of flat plate solar air collectors significantly. Use of fins in the solar air collector results in increased heat removal factor, useful energy gain, as well as collector efficiency values, and lowered the heat loss coefficients. The collector efficiency improves from 47.78% to 61.32%, with the addition of fins, at mass flow rate 0.01 kg/s and solar irradiance 1000 W/m2 . The maximum collector efficiency 61.46% of the finned air collector is achieved at air mass flow rate 0.01 kg/s and solar irradiance 1200 W/m2 . The findings of the study indicate that the finned solar air heater works the most efficiently at lower air mass flow rates and greater solar irradiances. Keywords: solar air heaters, solar energy, heat transfer.