Sustainable solar greenhouse drying of tomatoes: Kinetic modeling and environmental burden reduction

Abstract The novelty of this study is the application of a dynamic dual‐mode aeration system (DDMA) within greenhouse solar dryers for tomato drying. The system was evaluated using two greenhouse solar dryer (GHSD) configurations, namely a flat‐roof GHSD and a gable‐roof GHSD, with tomato samples prepared as 6 mm slices, quarters, and halves under salted and unsalted conditions. The dryers were compared with open sun drying (OSD) under Aswan, Egypt climatic conditions, where solar radiation ranged from 108 to 880 W/m 2 , ambient temperature from 24 to 42.3°C, and wind speed from 0 to 0.2 m/s. Drying behavior was strongly affected by dryer configuration, sample geometry, and salt pretreatment. The gable‐roof GHSD provided the fastest moisture removal, particularly for salted slices, which reached approximately 8.06% w.b. within 10 h, corresponding to a 44.4% reduction in drying time compared with OSD. The peak drying rate reached approximately 4.5 g water /g dry matter ·h for salted slices in the gable‐roof GHSD. Effective moisture diffusivity ranged from 0.58 to 2.65 × 10 −10 m 2 /s in the flat‐roof GHSD and from 0.70 to 2.84 × 10 −10 m 2 /s in the gable‐roof GHSD. Water‐removal productivity reached up to 0.140 kg water/h, while normalized carbon‐emission mitigation reached 1.608 kg CO 2 ‐eq/batch per 1 kWh kg −1 water. Thin‐layer modeling showed strong agreement between experimental and predicted moisture‐ratio data. These findings indicate that DDMA‐assisted GHSDs can provide a practical low‐carbon route for tomato drying and offer a basis for future scale‐up, quality optimization, and integration with renewable‐energy‐based postharvest processing systems.