The Savonius wind turbine is a type of vertical-axis wind turbine (VAWT) that came into being in the early 20th century. These simple turbines were invented by an engineer named Sigurd Johannes Savonius. The foundation of his design was laid by other engineers who had lived centuries before him, but his design was the most elegant and useful formation of the idea at the time. Even today, this type of wind turbine continues to be a reliable mode of generating electricity through wind power, and the design has proven to work for a variety of other uses that do not have to do with generating electricity.
Savonius Wind Turbine Design
Savonius wind turbines’ airfoils (usually numbering two or three) are shaped like scoops. These scoops catch the wind to move the turbine with drag power. While the drag power of three or more scoops is excellent for starting a turbine’s motion, a Savonius wind turbine cannot accelerate past the speed of the wind going past it. Another factor that causes the Savonius wind turbine to operate at lower speeds is its height. Usually its designed to be lower to the ground than other wind turbines. It is generally the case that wind speeds are lowest near the ground and highest up in the air. This means that other taller types of vertical wind turbines that accelerate with lift power, such as Darrieus wind turbines, are usually more effective at generating a large amount of electric power. The upside for Savonius wind turbines is that they are generally less expensive and more sturdy than Darrieus wind turbines.
A Variation on the Savonius Wind Turbine
A fairly new take on the Savonius wind turbine design is the airborne wind turbine, which would basically take a Savonius wind turbine and tether it to the ground. The axis would actually be oriented horizontally. When the wind would blow hard enough, the kite would take flight and the airborne wind turbine would spin and create energy. An entire field of these airborne wind turbines would be a fantastic sight indeed!
Where are Savonius wind turbines most useful?
Savonius wind turbines are great for generating electricity in rural and urban cities and for providing additional energy to land and sea vehicles, but they are especially useful for providing smaller amounts of electrical power in areas where it will be difficult provide ongoing maintenance or where extreme conditions require the wind turbine to be particularly strong. For example, you can find Savonius wind turbines in places like the Sahara Desert and Antarctica where the weather is extreme, the availability of appropriate transportation is hard to come by, and wind turbine experts are not necessarily hanging around biting at the bit to fix turbines when problems arise.
While the Savonius turbine’s design is wonderful for harvesting clean wind energy, its uses do not stop there. You can also find the Savonius design in anemometers (a device used for measure wind speed), in some types of water pump, car ventilators, and even in unique designs for backyard clothing dryers.
Image of Savonius above taken from German Wikipedia.