A vertical wind power generator, also called vertical-axis wind turbine (VAWT) is a type of turbine whose axis of rotation is perpendicular to the wind flow and the ground. The concept is as simple as that of a water or hydro-turbine where a jet or cascade of water hits the turbine directly, initiating the rotational movement. Save and except that in the case of VAWT, the wind flow does the trick, thereby generating electricity. It does not have any propeller-like blade as in a horizontal-axis wind turbine or HAWT.
Vertical-axis wind turbines usually fall into two categories: (a) Darrieus Turbine and (b) Savonius Turbine, both of which are no more used now-a-days. However, the Darrieus Turbine that was designed by Georges Jean Marie Darrieus, a French aeronautical engineer in 1932 consist of a number of aerofoil that were vertically mounted on a rotating shaft whose biggest snag was its unwieldy structure. Also, it could not start on its own and needed a ‘push’. Nevertheless, this was eventually solved by connecting the contraption to the grid. In fact, the grid power was made to act on the turbine’s generator, turning into a motor which started the rotational motion. However, no tower was needed for installing these types of turbines as they were mostly set in ground level.
The Savonius Turbine, also a vertical-axis wind turbine consisted of a pair of opposing concave vanes rotating round a central vertical axis Customary Savonius rotors were open in the center, permitting cross flow of air in an S formation, passing the inner edges of the rotating vanes. However, these also died a natural death, mostly because of cumbersome design structures and unstable installation process.
Although horizontal-axis wind turbines (HAWT) now rule the market, engineers do not consider the system to last long because of several practical reasons. Moreover, the ERDA-NASA design (devices that run through propeller-like blades) may not eventually prove as cost effective as originally conceived. It has also been estimated that for generating enough power for an average dwelling house (leaving aside push sale of small rooftop models that are neither good for the roof nor for generating adequate electricity) may need propellers at least 25 feet in diameter. To achieve higher outputs, larger diameter (125-200 feet) blades will be needed. And as the range increases, the production, installation and maintenance costs increase ten fold. On top of all that, the ERDA-NASA units require supplementary control mechanisms for keeping the unit perpetually turned to the air current, feathering the blades as well as provision for braking when wind velocity exceeds the rated limit. Since these controlling mechanisms also require power, the overall output is likely to go down substantially.
However this is no reason for you to review your decision to opt for wind energy. There are many other cheap wind power systems that are working just fine – in fact, an ever increasing number of people are today are going for wind power across the world. Many countries have gone to the extent of declaring their wind policy and their aim is to rapidly replace fossil fuel generated power with this safe and clean energy as soon as possible.
And there are many reasons for this. Do not forget – wind power does not create any pollution, it is cheap and it is hassle free as well. Plus, when you use wind power, you can save a lot on your power bills and there is very less maintenance cost as well. These are the main advantages of wind power. So go ahead and read this manual that teaches you where to set up the system in your home for best results, how to do it, how to wire the system, where to get the parts from cheaply and lastly, the all important safety precautions that need to be followed always.