Converting Waste Agricultural Biomass into a Resource - UNEP

Solar Collector
The solar collector has a matt black-coated GI absorber sheet, and a single
Plexiglas cover positioned about 5 cm above the absorber. The metal walls of
the collector box are insulated with 8 cm thick glass wool to reduce heat
losses. The solar collector supplies the hot air required for dryer operation
during the day time. The dimensional details of the collector are presented in
Figure 8.2. The solar collector is attached to the backside of the drying
chamber at an angle of 15° to the horizontal. Hot air from the collector enters
the drying chamber at the bottom and rises through the several trays which
hold the products to be dried. A fan inside the drying chamber assists the flow
of hot air from the collector up through the trays.
Gasifier Stove
The design of the gasifier stove was adapted from the gasifier stoves
developed at the Asian Institute of Technology. Details of this stove are given
in Package 2. It consumes about 2 kg of coconut shell or wood charcoal per
hour and is capable of providing drying temperatures up to 60°C.
Performance tests showed that a batch of 50 kg of sliced pineapple with an
initial moisture content of 85% (wet basis) could be dried to a final moisture
content of 20% in about 18 hours at a drying temperature of 60°C. The total
cost of the complete drying system (including the solar collector and gasifier
stove) was about US$1,120 as of Feb 2002.
Application
Drying fruits, fish and herbal products
Examples of Real Life Applications
Research Level
Solar-Biomass Hybrid Cabinet Dryer
FD50Solar Laboratory at University of Philippines Diliman (UPSL/UPD)
and the Institute of Agricultural Engineering - University of Philippines Los
Banos (IAE/UPLB)
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