Abstract
ABSTRACT Solar drying provides an eco‐friendly and energy‐efficient alternative to traditional drying methods, making it a practical choice for agriculture and food preservation in regions with high solar availability. This paper describes research on an indirect solar drying (ISD) system that uses a flat‐plate collector with three baffle geometries: simple, triangular, and serpentine. The performance of the ISD was evaluated by the drying of mint plants, a significant agricultural product in the arid climate of El‐Oued, Algeria. Experimental measurements were conducted over several days in May under actual weather conditions, with data from the most stable day chosen for analysis. Measurements were taken from 8:00 a.m. to 5:00 p.m. A thorough evaluation of the system's thermal performance was performed, focusing on key factors such as collector temperature, drying chamber temperature, moisture content, mass loss, shrinkage rate, and thermal efficiency. The results indicate that the serpentine baffle design significantly improved solar dryer performance, reaching a maximum outlet temperature of 67°C (vs. 62°C for triangular and 56°C for simple designs) and a drying chamber temperature of 52°C (4°C–6°C higher than others). The thermal efficiency attained 36%–48%, above the triangular (29%–38%) and simple (15%–32%) configurations. Drying was fastest with the serpentine baffle, reducing mint moisture from 78% to 0% in 7.5 h (by 3:30 p.m.)، finishing 1 h earlier than the triangular and 1.5 hours earlier than the simple design. A logarithmic model best fit the data ( R ² = 0.9964, RMSE = 0.0178), confirming a strong correlation between baffle design and the efficiency of the drying process.