One of two main types of vertical-axis
wind turbine (VAWT); the other is the Darrieus
turbine. Invented in Finland in the 1922 by Sigurd J. Savonius, the
Savonius turbine is S-shaped if viewed from above, and has two, three, or
more scoops to catch the wind. Although, unlike the Darrieus turbine (which
uses airfoils and aerodynamic lift to turn the blades), the Savonius turbine
can't rotate faster than the speed of the wind, it does yield a high torque.
|A low-cost Savonius turbine for domestic use developed
by EMAT Ltd, of Gateshead, England
It is useful for grinding grain, pumping water, and many other tasks, but
its slow rotational speeds make it unsuitable for generating electricity
on a large-scale. Small electricity-producing Savonius turbines for domestic
use, however, such as the one shown here, have been developed.
- Having a vertical axis, the Savonius turbine continues to work effectively
even if the wind changes direction.
- Because the Savonius design works well even at low wind speeds, there's
no need for a tower or other expensive structure to hold it in place,
greatly reducing the initial setup cost.
- The device is quiet, easy to build, and relatively small.
- Because the turbine is close to the ground, maintenance is easy.
- The scoop system used to capture the wind's energy is half as efficient
as a conventional turbine, resulting in less power generation.