Converting Waste Agricultural Biomass into a Resource - UNEP

Solar-Biomass Hybrid Cabinet Dryer 95
Nepal, Pilot Demonstration
Crop
Residue
Process
Equipment
Main Product
Wood, etc.
Fuel wood, wood chips, twigs, and briquettes
Combustion
Solar-biomass hybrid cabinet dryer
Heat for drying
Technical Description of Technology
The hybrid cabinet dryer (Figure 7.1) consists of an air-heating solar collector,
a drying chamber, a biomass stove-heat exchanger-chimney assembly, and a
chimney attached to the drying chamber at the top. During daytime, ambient
air is heated by the solar collector, and the hot air is passed through trays
kept inside the drying chamber where products to be dried are loaded. During
poor weather conditions and at night if required, the biomass stove provides
the hot air required for drying. A heat exchanger is used to avoid direct
contact of flue gas with the product. Direct contact of flue gas might
contaminate the product as the flue gas generally contains smoke, soot, and
other harmful gases.
The stove can be operated using fuels such as fuelwood, wood chips, twigs,
and briquettes. As honeycomb briquette is a popular fuel in certain parts of
Nepal, production of honeycomb briquette is explained in detail in this
package. The products are spread in thin layers on several trays inside the
drying chamber. Warm moist air from inside the drying chamber exits to the
atmosphere through the chimney at the top, assisted by draft created in the
chimney. Technical specifications of the solar-biomass hybrid cabinet dryer
95 http://www.retsasia.ait.ac.th/booklets/Dissemination%20Booklets-Phase%20III/Tech%20pack-Drylow%20resl.pdf
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