A HYBRID DRYER TO DRY SOLID WASTE

The usage of solar heating for drying application is limited only to sunny days. The process is interrupted during the cloudy or rainy days and also at night. This paper presents an experimental evaluation of a solar dryer performance using solar energy as main input and biomass burner as the auxiliary source of energy to compensate for the absence of the solar radiation. The conceptual design of the experimental model is based on analytical modeling of the drying process using solar, backing up heat source, and both of them simultaneously. Several compatible design criteria have been adapted for the dryer and the biomass burner so that it can be used in the remote places. The experimental results have shown considerable improvement in the hybrid dryer performance by using the biomass backup. Drying of 2.5 kg of empty fruit bunch (EFB) fibers within 2 hours has shown a moisture content reduction of 14% under solar mode only, increased to 33% using the backup drying mode, while it is enhanced to approximately 50% by combining the solar and the backup drying mode. The proposed design can be implemented in various scales as prototypes for commercial producers of agricultural products. Also, it is electricity free which makes it suitable for usage in rural areas.

Keywords: hybrid solar dryer, palm oil waste, solar drying, solid waste.