Drying of Sliced Apple and Carrot with Heat Pump Technique: Performance Analysis

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AKTAŞ M., KOŞAN M., Catalbas C., Gok M.

JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, vol.22, no.3, pp.523-529, 2019 (ESCI) identifier


In this study, 2 mm thick sliced carrots and apple slices were dried at a temperature of 40. and a drying air velocity of 1.5 m/s in heat pump dryer which has a waste heat source, and drying kinetics and system performances were analyzed. Drying system consists of fan with frequency inverter, heat pump system and drying chamber with load cell. The change in moisture content obtained with the experimental data was from 7,19 g water/g the amount of dry matter to 0,098 g water/g the amount of dry matter for carrot at 9 hours, and from 4,55 g water/g the amount of dry matter to 0,13 g water/g the amount of dry matter for apple at 11 hours. Whole system heat pump performance coefficient values were varied between 3 and 3,44 for carrots and between 3,15 and 3,43 for apples. It is seen that the performance coefficient of the heat pump is increased by transferring the waste air from the drying chamber to the evaporator surface, and 70% of this air sent to the evaporator surface is composed of waste air and 30% is composed of ambient air. It has been observed that heat pump dryer prototype, which has been tested for performance, can be used successfully in vegetable-fruit and other drying applications, especially at low temperatures.