Evaluation of Energy Consumption of Potato Slices Drying Using Vacuum-Infrared Method

Objective: The main objective pursued in this paper is to investigate the energy consumption for drying of potato slices using vacuum-infrared drying method. Methods: Drying of potato slices with the thicknesses of 1, 2 and 3 mm were conducted at vacuum levels of zero (without vacuum), 20, 80 and 140 mm [Hg], infrared radiation at power levels of 100, 150 and 200 W in the three repetition. Results: The results show that with the slice thickness decreases, acts of vacuum and increasing lamp power, energy consumption be reduced. Maximum of energy consumption occurred in a vacuum of 140 mm Hg, but in general it can be stated that by applying vacuum, energy consumption is reduced due to the shortening of the drying time. Data analysis showed that use of vacuum in conjunction with infrared radiation drying increased energy consumption in comparison to merely infrared drying. In the combined vacuum-infrared process, drying time and consequently energy consumption decreased in comparison to the merely infrared drying. The maximum thermal utilization efficiency (31.01%) and minimum energy requirements (5.3 kWh/kg H2O) was calculated for drying of potato slices computed at infrared power of 150 W without vacuum at thickness of 1 mm. The minimum thermal utilization efficiency (2.13%) and maximum energy requirements (185.14 kWh/kg H2O) for drying of potato slices was achieved at infrared radiation power of 100 W with vacuum level of 80 mm [Hg] at thickness of 2 mm.