Drying kinetics of tomato (Solanum lycopersicum) and Brinjal (Solanum melongena) using an indirect type solar dryer and performance parameters of dryer

Abstract

Tomato (Solanum lycopersicum) and brinjal (Solanum melongena) are food products that are frequently wasted in Indian markets as their shelf lives are only a few days. An indirect type solar dryer (ITSD) has been developed. It’s performance and drying kinetics of brinjal and tomato slices have been analyzed. The moisture content of tomato decreased from 15.667 to 0.803 kg/kg of dry basis (db) and that of brinjal reduced from 10.111 to 0.498 kg/kg of db. The drying curve was fitted with the different models of existing studies. The average effective moisture diffusivity is estimated and it is 3.60 × 10−9 and 4.00× 10−9 m2/s for tomato and brinjal, respectively. Mass transfer coefficient was in the range of 0.82 × 10−4 to 2.85 × 10−3 m/s for tomato and 1.11 × 10−4 to 3.32 × 10−3 m/s for brinjal. The heat transfer coefficient was in the range of 0.089 to 2.888 W/m2 K and 0.1066 to 3.3564 W/m2 K for tomato and brinjal, respectively. The activation energy for tomato and brinjal was 21.19 and 19.46 kJ/mol, respectively. The average thermal efficiency of the collector and dryer was 59.05% and 31.4% during tomato drying and 58.42% and 25.16% for brinjal drying, respectively.