Exergy analysis and kinetic study of tomato waste drying in a mixed mode solar tunnel dryer

Abstract

A mixed mode solar tunnel dryer was designed and fabricated for the purpose of drying fruit wastes from food processing industries. The dryer consists of a blower, a solar flat plate collector, a green house chamber with detachable trays for easy handling of biomass and a chimney. Tomato waste was taken as the raw material for the drying process. A 2 kg of tomato waste with initial moisture content of 71.1% (wb) was evenly spread on the surface to a thickness of 0.5 cm. Experimentation was carried out in the geographical location of Vellore, India having 12.91°N latitude, 79.13°E longitude. Equilibrium moisture content of the biomass using mixed mode solar dryer was attained in 7 h while it took 15 h in open solar drying. During the drying operation, the temperature of the dryer varied between 42 and 67°C. Exergy analysis and thin layer drying kinetic studies were conducted for better understanding of the various parameters that influence the drying of tomato waste. The study showed that mixed mode solar drying is an eco-friendly method for mitigation of fruit wastes and it is more effective than open solar drying.