Raw material of fresh wild ginger is obtained from Balitro Bogor. Wood is used as biomass fuel. Moisture
content of wild ginger is determined by using drying oven method. Solar irradiation measurement is equipped by
pyranometer. Anemometer kanomax-type is used to measure airflow of drying air and ambient air. Another
apparatus used are adiabatic bomb calorimeter, digital electronic balanced, thermocouple and thermo-recorder.
Relative humidity of drying air and ambient air are determined by measuring of wet bulb and dry bulb thermometer
and also calculated by using psychrometric chart. The measurement apparatus is depicted in Fig. 1.
The main equipment of rack type - Greenhouse-effect solar dryer designed by Wulandani dan Nelwan [6] is a
transparent building where the product dried is spread on the racks within the structure. The dryer is described in Fig
2. Solar energy is trapped into the transparent building and lead to increasing of air temperature inside the building
[4]. To overcome the cloudy and rainy condition, biomass fuel combustion in the biomass stove is provided. The
dryer consist 144 trays (dimension of 0.5 m x 0.5 m), four blowers (power of @ 80 W), burner and cross-flow heat
exchanger.