Comparison of energy consumption in the convective and freeze drying of raspberries

Freeze-drying has proven to be one of the best drying processes thus far. The drying process itself lasts considerably longer than any other drying method. This paper makes a comparison of the energy consumption and time required for drying 100 kg of raspberries using lyophilization and convective drying. The calculations of energy consumption were performed for both drying methods, as well as their subsequent comparison. When calculating the energy consumption, special attention was paid to all consumers involved in the drying process (both directly and indirectly). The results obtained show that the energy consumption in the freeze-drying of raspberries was higher than that recorded in the convective drying method. The freeze-drying time was slightly more than 3 times longer than the convective drying time. Relative to the energy consumption and drying duration, the convective drying process was found to be far more efficient than the freeze-drying process.