Energy and Exergy Analyses for Drying Process of Apple Cubes in a Hot Air Dryer

In this study, energy and exergy indices for convective hot air drying of apple cubes were investigated and effect of the air parameters on them were assessed. Drying experiments were carried out at the air temperature levels of 45, 55 and 65 °C, and the air velocity levels of 1, 1.5 and 2 m s-1. Average values of energy utilization were obtained to be in the range of 0.324-1.543 kW. The minimum and the maximum values of specific energy consumption were obtained for drying at air temperature of 65 °C and air velocity of 1 m s-1, and at air temperature of 45 °C and air velocity of 2 m s-1, respectively. Average values of input exergy, output exergy and lost exergy were obtained to be in the range of 0.09106-0.52095 kJ s-1, 0.06401-0.46135 kJ s-1 and 0.02705-0.05960 kJ s-1, respectively. Average exergy improvement potential rate was increased with increasing air temperature and air velocity, and varied from 0.00804 kJ s-1 to 0.01175 kJ s-1.