The Effect of Inlet Air velocity on Efficiency of the Heat Pump Dryer

Abstract

The objective of this research aims to study the effect of inlet air velocity on the efficiency of heat pump dryer which consist of open type compressor driven by electric motor 2.2 kW, pressure at condenser and evaporator were 2.00 MPa and 0.20 MPa, respectively. This study was conducted using banana chips which average diameter were 30 mm. and initial moisture was 166.07 – 194.15 % db. Controlled total drying time at 10 h and the air temperature at inlet was 70^°C at all velocities. The variables of this study was Specific Moisture Extraction Rate (SMER). Air flow rate at inlet was varied from 0.25, 0.35 and 0.45 m/s. The hot and humid air after drying was fully recovered. At the inlet air velocity 0.25, 0.35 and 0.45 m/s, the Coefficient of Performance (COP) were 2.62 2.44 and 2.38, respectively. At the inlet air velocity 0.45 m/s, the average Specific Moisture Extraction Rate (SMER) was maximum at 0.071 kg_{water evap}/kW-h and decreased as the inlet air velocity was down. Because the wind speed in front of drying room at 0.45 m/s shown the highest of Specific Moisture Extraction Rate (SMER), cause the highest performance of dryer.