Converting Waste Agricultural Biomass into a Resource - UNEP

Although designed for honeycomb briquettes, the stove has been found to
work well with other biomass fuels as well, such as fuelwood, wood chips and
twigs. In locations where honeycomb briquettes are not available, this stove
can thus be operated using these other fuels.
Heat Exchanger
A heat exchanger transfers heat from the hot flue gas from the biomass stove
to the drying air entering the drying chamber through the solar collector. The
heat exchanger, made of 24 SGW aluminum sheet, is fitted above the level of
the solar collector’s air outlet. It is of fin and tube design, with a rectangular
tube, on which aluminum fins are attached to enhance the heat transfer
surface area. Hot flue gases from the biomass stove enter the heat exchanger
at one side, and leave through a chimney at the other side. Process air, which
gets heated up by the heat exchanger surface, flows up through the trays
which hold the products to be dried. The dryer will be useful for commercial
scale users for processing products such as fruits, vegetables and fish. The
dryer has been tested for drying products such as radish, carrot, ginger and
mushroom. As uninterrupted continuous drying is possible with this type of
dryer, the quality of the dried product is better than that dried in the open sun
or in the solar dryer.
Examples of Real Life Applications
203