Energy–exergy analysis and mathematical modeling of cassava starch drying using a hybrid solar dryer
Suherman Suherman, Evan Eduard Susanto, Asif Widodo Zardani, Nur Haniza Roviqoh Dewi, Hadiyanto Hadiyanto
Abstract
In this study, we aimed to energetically and exergetically evaluate the usage of a hybrid solar dryer system for cassava drying via a series of drying experiments. The experiments were performed beginning at 10.00 A.M. (hereafter, in local time) until the moisture content of cassava starch became constant at a value less than 14% on a wet basis at drying temperatures of 40 °C to 60 °C and drying times of 180–240 min. The results demonstrated that the highest overall dryer energetic efficiency was 20.82%, which was achieved at a drying temperature at 60 °C, and that the maximum energetic efficiency of 27% was recorded at 11.00 A.M. The exergy flows fluctuated during the drying process and were dependent on the solar radiation and drying conditions; however, the exergetic efficiency of the dryer was 25.1%–73.8%. Comparison of the fitting models denoted that the Page model was the most suitable model for describing the experimental drying performances. The calculated effective diffusivity constant (Deff) and the activation energy (Ea) during the drying process from 50 °C to 60 °C were 3·× 10−10 m2/s and 15.3 kJ/mole, respectively.