Exergy and energy analysis of the solar drying processes of tomatoes in Tunisia

A comparative study of the drying characteristic of thin layer Tomato, dried in a mixed mode solar greenhouse dryer and under the open sun is presented. In this study, there was a reduction in drying time in a solar greenhouse dryer as compared to the open sun drying. The moisture content of tomato was reduced from its initial moisture content of 20.27 (g water/g dry matter) to the final moisture content of 0.36 (g water/g dry matter) in 31 h and 48 h, respectively in the greenhouse solar dryer and under the open sun. To estimate the best drying model, three different mathematical models were applied to the experimental moisture ratio data. During the drying experiments, the exergy efficiency of the dryer was varied between 16.44 %-70.47 %. The overall energy efficiency of the dryer was 42%.