THIN LAYER DRYING MODELING OF APPLES AND APRICOTS IN A SOLAR- ASSISTED DRYING SYSTEM

Abstract

This work presents the drying process of apricots and apples which have been considered for drying in a solar-assisted forced convection tray dryer. The logarithmic model has been used to describe the drying behavior ofapples and apricots at different air temperatures (50 °C to 80 °C) and at different air velocities (0.5 m/s to 2 m/s)based on experimental data from several studies.The slice thickness of apples has been assumed at 10 mm with initial moisture content 87 % d. b; the maindiameter of apricots was 40 mm with initial moisture content 80 % d. b. The changes in moisture content withdrying time during the drying period have been presented indicating the absence of the constant rate period.In addition, drying air flow rates and temperatures had an important effect on the drying time and on themoisture removal from apricots and apples. Finally, the effective moisture diffusivity values have been estimatedfrom Fick’s diffusion model pointing out that it has been increased with the increase of the drying air temperature.