Experimental Research of Drying Red Chili by Two Methods: Solar Drying and Low - Temperature System Drying

Abstract The objective of this research was to experiment of solar drying and Low-Temperature system drying (45-50%RH, 27-30°C) for drying red chili. Solar drying during daytime (greenhouse dryer) and during at night using climate control system to coordinate with air conditioner in drying. The Low-Temperature system consists the humidity control unit (ultrasonic), air-conditioner, temperature and relative humidity sensor, heating coil and microcontroller unit. For Low-Temperature drying process, climate control system controls the compressor in the air conditioner by turn on-off to control the temperature and relative humidity in the chamber. The dehumidification process by controlling the temperature of the surface evaporator coil is decreased to the dew point temperature, making water vapor in the air condensed to be water drops. The result of solar drying and Low-Temperature system takes 52h to reduce the moisture content of about 74% to 13.5% (w.b). For temperature and relative humidity of the solar drying at 50 °C and 36%RH by average, in during daylight and at night with Low-temperature drying system by the climate control system coordinate with air conditioning system in moisture reduction at 27-30°C and relative humidity at 45-50%RH for drying chili in the night. These processes were found to have average temperatures and relative humidity for drying at 27.55°C, 47.37% RH., moisture condensation rate and specific energy consumption at 2.16 kg water /h and 0.75 MJ/kg.