Studi Implementasi Sistem Kendali On-Off Pada In Store Dryer (ISD) Untuk Komoditas Jagung

Abstract

In Store Drying is a drying method that uses ambient air as the drying medium and usually applied for grain. In Indonesia, although the humidity is relatively high, this drying method can still be applied by using an appropriate control system. In this research, a control system algorithm had been developed based on comparing the potential of ambient air with the air condition inside the ISD. The control system hardware was constructed based on the algorithm and then was tested for two different ambient air conditions. Corn was used as the material being dried. Simulation based on heat and mass balance was also performed in order to obtain the performed of the control system. The control system constructed in this research included a power supply, a control circuit, a parallel port circuit with IC74244, and circuit for sensor SHT75. The control system selected the ambient air used for drying of grain in store dryer. The performance test showed that with the average ambient air temperature of 32,8oC and relative humidity of 51,93%, the system could dry 1201,2 kg of shelled corn from the initial moisture content of 17,61% to 12,37%d.b. within 50 hours while the system could dry 915,0 kg from the initial moisture content of 18,02% to 12,25%d.b. within 40 hours when the average temperature was 31,14oC and relative humidity was 54,16%. The simulation performed showed that by using on-off control system, an amount of 350 kg/m2 shelled corn can be dried from moisture content of 18% to 15%d.b. within 33 hours with energy consumption 175MJ. Without the control system the same amount of the shelled corn the drying time was 68 hours and then the energy consumption was 360MJ.