Experimental study and numerical modelling of drying characteristics of apple slices

► A laboratory device permitted us to achieve several tests for different conditions of the apple slices drying. ► The air drying conditions as radiation intensity are the influential parameters. ► This study shows the considerable advantages of the intermittent drying of agricultural products. ► Convective and intermittent drying presents an energetic gain. A significant gain of time and energy is gotten by an increase of the airflow temperature and a reduction of the air velocity. The purpose of this work is to quantify the energetic interest of convective and intermittent drying process of natural products. This drying mode has been achieved within a climatic tunnel blower. This laboratory device permitted us to achieve several tests for different conditions of the apple slices drying. In the intermittent case, a variation of the air temperature and air velocity values permitted us to find the most economic velocities for the drying of the apple thin slices. The numerical simulations in the intermittent tests, give us more information on what really happens to the product during periods of interruption. The drying kinetics at the resumption increases with the air temperature. Then, we gain in energy and in overall drying time. These studies show the considerable advantages of the intermittent drying of agricultural products and confirm the preservation of their qualities and the reduction of the drying time.