Solar tunnel drying characteristics and mathematical modelling of tomato

Solar drying experiments of tomato were conducted in Izmir, Turkey. In this purpose, new type tunnel solar dryer was designed and manufactured. Solar dryer consist of an air collector, drying chamber and an air circulation system. Heated air in solar air collector was forced through the tomatoes by a blower. Rio Grande type tomato was used for drying experiments. During the drying period, drying air temperature, relative humudity, air flow rates, solar radiation, and lose of mass were measured continuously in different part of the dryer. Drying time was examined with mass ratio as exponantial and polynomial correlations. Twelve different mathematical models available in literature were compared using their coefficient of determination of estimate solar drying curves. According to statistical analysis results, the two-term drying model has shown a better fit to the experimental drying data of tomato with a coefficient of determination R 2 of 0.9967 as compared to other models. © 2008 TIBTD Printed in Turkey