Vertical Wind Turbines suitable for small deployments are usually rated to produce up to 5KW but more commonly they produce up to 2 KW.
As their name suggests their blades rotate around a vertical axis. This is quite different to the horizontal turbines which look more like an airplane propeller.
One of the main differences between vertical axis and horizontal axis turbines is that a vertical turbine does not need to swing into the wind as it shifts direction. The technical term for this is yaw. In order to capture the power of the wind all horizontal turbines need to do it. A vertical turbine can harness the wind?s power from any direction and so is simpler in design with fewer moving parts and less maintenance.
Vertical axis turbines come in two different types. There are lift turbines and drag turbines. Both have their advantages and disadvantages.
The lift devices are also know as Darrius turbines after their inventor George Darrius. The rotors are an aerofoil type of blade which operates more efficiently that the drag style of blade. This means that the turbine can have a smaller rotor for a given rated output. The disadvantage of higher rotor speed is that they can be noisier.
The drag turbine as we have discussed is not as efficient as the lift turbine, but it does have a number of advantages. It is self starting. This means that the design can be simpler. It also runs more slowly. This means it is less noisy. Overall drag turbines have been available for longer than the lift turbine and have a good track record of operation in the real world.
Author: Gavin RyderThis author has published 2 articles so far.