Advantage of Vertical Axis Wind Turbine Technology
While the image we would all tend to think of when we imagine wind turbines is of large blades spinning in the wind like propellers run in reverse, this is in fact a form of wind turbine which has numerous engineering drawbacks. Many of these drawbacks, however, are corrected by turning the turbine ninety degrees, to create the vertical-axis turbine.
What is a Vertical Wind Turbine?
A vertical (or vertical-axis) wind turbine is a turbine that spins around an up-down axis, rather than a forward-backwards one. While the horizontal-axis turbine has familiar examples such as the windmills of the past, it is more difficult to imagine what a vertical-axis wind turbine looks like. One particular form of vertical turbine resembles an elongated water wheel turned on its side, with of a set of airfoils resembling cut-out tubes arranged in a bundle, with all the tube segments pointing the same way around the circumference. Others have fewer airfoils spaced further from the center and open space in the middle, like an oak barrel with most of its timbers removed.
Aside from the form of the rotors, the rest of the process is the same for any sort of wind turbine. The rotors spin a shaft, which connects to the generator through a gearbox, which increases the rate of rotation. Resembling electrical motors run in reverse, all rotary electric generators operate on the same principles.
What are the Functional Differences between Horizontal and Vertical Wind Turbines?
While horizontal turbines must be pointed in the right direction in order to capture the wind at any particular time, vertical turbines need no such adjustment they work equally well with winds coming from any direction.
Vertical wind turbines with relatively low cut-in speeds can be built which can produce electricity a greater fraction of the time. Compared to a horizontal turbine of equivalent power, the more compact vertical configuration takes up less space. Finally, vertical axis turbines tend to run more quietly than their horizontal counterparts.
Finally, vertical axis turbines are much better suited to be used in urban areas due to their compact form and ability to run at low wind speeds.
Though horizontal axis wind turbines have become the familiar image of wind generators everywhere, later evolution in technology often outperforms the first incarnation; this could be true of vertical-axis turbines, which have many advantages over traditional horizontal-axis turbines. As the technology of vertical-axis turbines matures and their benefits become more apparent, vertical turbines may command an increasing share of the wind market.