Experimental Study of Solar Air Dryer Performance Utilized with Flat and Perforated Absorber Plates

In order to determine if perforated absorber plates with circular holes of 6 mm and 3 mm diameter, respectively, in the solar collector enhance the performance of a dryer compared to the traditional flat absorber plate, an experimental investigation was conducted under Iraqi climatic conditions to investigate the enhancement of the performance of an indirect solar air dryer system with forced convection.The experiments were conducted in June 2024 at Baghdad city, located at 33.3N latitude.A solar air dryer comprises a solar air collector inclined at 30 towards the south, an electric fan, and a drying chamber.In the present study, the surface of an absorber plate was modified by forming circular holes on the surface of the plate, which contributes to breaking the thermal barrier layer on the plate and thus improving the heat transmission from the hot plate to the air.Modifying the absorption plate results in a heightened thermal efficiency of the solar air collector compared to the traditional flat absorber plate.The results confirmed that the solar collector with a perforated absorption plate enhanced the solar dryer's effectiveness.A perforated plate with a diameter of 3 mm outperformed both the perforated plate with a diameter of 6 mm and the flat absorber plate.Results indicated that using the perforated plate with a diameter of 3 mm resulted in a 50.32% improvement in collector thermal efficiency and a 27% improvement in dryer efficiency when compared with the perforated plate with a diameter of 6 mm and the flat absorber plate.