MATHEMATICAL-MODELING OF THE THIN-LAYER SOLAR DRYING OF SWEET-POTATO SLICES

An indirect solar dryer was used to study the drying of sweet potato s lices. The solar drying rates of sweet potato slices were affected by the fluctuating chamber temperature over the drying period. Solar dryi ng rate curves exhibited a constant rate period and one linear falling rate period. A mathematical model for solar drying of sweet potato sl ices was derived based on the simplified form of the Fick's diffusion equation. The mathematical model could satisfactorily describe the sol ar drying of sweet potato slices to a moisture content below 20% dry b asis. The mean effective drying chamber temperature and sample thickne ss were the main factors that affected the solar drying process for sw eet potato slices.