Basic Principle
A solar food dryer consists of a flat box (frame) placed at an angle, with an open bottom and top, so
that the air can circulate. Corrugated metal sheet, painted black, is placed on the bottom of the box.
The black colour absorbs the sun rays and heats the air above. The frame is covered with glass,
transparent plastic foil or a plain garden plastic. The warm air reaches 40 – 50°C, rises and leaves
the heating box through the top opening and flows through the drying chamber with the drying
screens. Cool environment air is sucked off through the bottom opening.
The dryer’s angle must be adapted to the respective geographical latitude: In Europe steeper (60°),
and in the tropics flatter (30°). With a flat angle, air circulation can be improved by adding a chimney.
The solar dryer only works with direct solar radiation and works best during dry periods when there
is little humidity in the air.
How to build a Solar Food Dryer
