Savonius Wind Turbine

savonius-wind-turbine

The Savonius wind turbine is a type of vertical-axis wind turbine invented by the Finnish engineer Sigurd Savonius in the 1920’s. It is one of the simplest wind turbine designs. It consists of two to three “scoops” that employ a drag action to convert wind energy into torque to drive a turbine. When looked at from above in cross-section, a two scoop Savonius turbine looks like an S-shape. Due to the curvature of the scoops, the turbine encounters less drag when moving against the wind than with it, and this causes the turbine to spin in any wind regardless of facing.

Drag-type wind turbines such as the Savonius turbine are less efficient at using the wind’s energy than lift-type wind turbines, which are the ones most commonly used in wind farms.

More of the wind’s energy is lost in the conversion to electrical energy. As a result, Savonius wind turbines are not commonly the preferred design for energy production either for commercial use or for home energy generation.


Uses For Savonius Wind Turbines

The Savonius wind turbine design is used wherever small amounts of power need to be generated by turbines that require little or no maintenance. They are also a good choice for many wind turbine uses other than electricity generation. Many anemometers are based on Savonius wind turbine design, as these instruments measure wind speed and efficiency is of no concern in that application. Savonius turbines are also used on deep-water buoys to generate small amounts of electricity. The low maintenance of the Savonius turbine is more important for that use than the low amount of power it generates. Savonius wind turbines are also seen in the Flettner Ventilator, used as a cooling fan or ventilator on the roofs of buses and vans. The turbine itself drives a fan that pulls air out of the vehicle.

Manufacturers

Savonius wind turbines are manufactured by a number of companies, including Huopeng Industry Co. Ltd. and Shenzhen. The price runs around $3 to $5 per watt of rated generating capacity.

Building Your Own

Although the Savonius wind turbine is not a good choice for home electricity production due to its low efficiency, it remains popular as an easy-to-build project that demonstrates how wind power is generated as well as the engineering principles that allow drag-type wind turbines to work. Designs for the generator are easily found online and it is not at all hard to build.

The blade design for a simple Savonius rotor is an S-curve around an axis in the middle. You can make one from metal or plastic drums or pipe sections. Simply cut the pipe section in half vertically. The two hemispheres are
attached to the vertical axis which drives the generator. The generator itself can be a small permanent magnet DC motor.

Advantages Of A Savonius Wind Turbine

The disadvantages of a Savonius turbine involve low efficiency and low power generation, which are of course quite serious for purposes of power generation and make this design not the best choice for producing significant amounts of power. The design does have advantages as well, however.

One major advantage is that the Savonius turbine is always facing into the wind, no matter what direction the wind is blowing. It does not need a mechanism for making it face into the wind, as lift turbines do.

The Savonius turbine also turns at relatively low speeds and does not stick out very far. These two things make the design less dangerous to birds, wildlife, and children than a lift turbine.

The Savonius turbine can be operated at lower elevations from the ground than a lift turbine as well, since it operates well in low-speed winds. It is not greatly affected by turbulence, again making it a good choice for wind
power use at low elevations where interference is the norm and turbulence is high.

Because it moves at lower speeds and does not have to be turned to face the wind, the Savonius wind turbine suffers from less wear and tear and stress than a lift turbine. As a result, it is much lower in necessary maintenance. Parts will not wear out as quickly and need replacing. All of this makes the Savonius a good choice where reliability and low maintenance are important, and high levels of power do not need to be generated.

  • author's avatar

    By: Neville

    New Zealand based entrepreneur and passive income machine. My views are my own a reflect me exactly. My family comes first and I believe a strong family unit is the backbone of any safe functioning society. I am a strong advocate for justice, which incorporates equity and fairness. I’m a skeptic and am always open to change any of my views based on evidence. I also love tennis and American muscle cars.

  • author's avatar

    Visit the author’s website