Evaluating Drying Behavior and Efficiency in Varied Shaped Samples Using Solar Drying: A Morphological and Kinetic Study

Abstract

This study evaluates the drying behavior, kinetics, morphology, efficiency, and heat and mass transfer phenomena of three differently shaped samples. A refined model was used to validate experimental results. The maximum recorded solar irradiance and ambient air temperature were 775 W/m2 and 40.5 °C, respectively, at 02:00 p.m. At this peak time, crop surface temperatures were 55.2 °C, 63.2 °C, and 70.1 °C for samples I–III, respectively, due to higher solar irradiance. The maximum drying rate for sample I was 0.017 g/g db.h at 11:00 a.m., gradually decreasing thereafter. For samples II and III, peak drying rates were 0.012 and 0.017 g/g db.h at 11:00 a.m., respectively. The highest drying efficiency of 26% was achieved in case I, with 24.5% and 22.5% observed in cases II and III. Prakash and Kumar's model, with root mean square errors of 0.0219, 0.01487, and 0.01831, effectively described the thin-layer drying kinetics. The developed drying system demonstrates superior cost-effectiveness, featuring low operating costs and a payback period of 1.25 years, outperforming other market options. Scanning electron microscopy (SEM) analysis has also been done to examine the surface morphology of the solar-dried food samples and showed brittle walls due to moisture loss, as indicated by SEM testing.