Optimized air distribution is important for the energy consumption in a batch drying process. Energy and exergy analyses for an innovative diagonal-batch dryer were performed using potato slices of 5 mm and 8 trim thicknesses at 55 degrees C and 65 degrees C. The exergetic efficiency, improvement potential rate (IP) and exergetic factor (f) were taken as performance parameters. The main component for improving the system efficiency was found to be the fan heater combination, possessing low exergy efficiency, high IP and high f values. The energy utilization, energy utilization ratio, exergy losses and exergy efficiency varied between 1.82 and 12.52 kJ/s, 0.04-0.59, 1.3-4.89 kJ/kg and 0.41-0.94, respectively for potato slices. The specific evaporation energy and specific product energy were found to be in the range of 4.78 -6.13 MJ/kg and 16.24-20.63 MJ/kg respectively. The outcomes of the analysis will provide insights into the optimization of a batch dryer for the maximum retention of quality parameters and energy saving. (C) 2015 Elsevier Ltd. All rights reserved.