DIY





The Scoop on Vertical Axis Wind Turbines


| 3/16/2009 9:32:00 AM



One type of wind turbine that’s been getting a lot of attention these days is the vertical axis wind turbine. Even famous Hollywood stars like Ed Begley, Jr., are touting their supposed advantages over conventional wind turbines.

In a vertical axis wind turbine (VAWT), the blades are attached to a central vertical shaft. The shaft is attached to an alternator located at the bottom of the shaft, sometimes even at ground level. When the blades rotate, they spin the rotor of the generator, producing electricity.

Vertical axis wind machines have been around for a long time, about 3,000 years. The reason you see so few of them is that they’ve failed miserably.

That hasn’t stopped inventors (who are apparently unaware of their disappointing history) from rolling out new models and singing their praises. One refrain in their song of praise is that VAWTs can capture wind from any direction, which is true of horizontal wind turbines, too. The difference is that VAWTs are always oriented into the wind whereas conventional wind turbines turn into the wind as wind direction changes, thanks to the tail vane. No big deal there.

Proponents also like to claim that VAWTs are immune to turbulence that wrecks havoc with horizontal axis wind turbines (HAWTs). Turbulence is crazy airflow that occurs downwind from buildings and other obstacles on the ground, known as ground clutter. In turbulent areas, winds can flow in a number of different directions. This, in turn, is pretty hard on conventional wind turbines and one reason they are mounted on tall towers. Tall towers place them in the smoother, stronger, more energy-rich higher-level winds.



The VAWT does have a slight advantage in dealing with wind direction shifts, but turbulence also wreaks havoc on their blades, increasing fatigue. Fatigue leads to failure. Blades can crack and break.

BootDr
11/28/2014 4:40:02 PM

Look at TMA Wind's VAWT at www.tmawind.com


Luann Elizabeth
8/6/2011 2:50:56 PM

What ever happened to the technology that created a beautiful "windmill" that spun silently with virtually no breeze at the 1976 Toward Tomorrow Fair in Amherst MA? I keep trying to find a wind turbine like that one. There were just two blades that twisted a half turn from top to bottom (as I remember it). Or has it gone the way of the electric car? (see DVD: Who Killed the Electric Car?)


wind generator_1
5/30/2010 1:46:35 AM

Wind turbines are used to generate electricity from the kinetic power of the wind. Historical they were more frequently used as a mechanical device to turn machinery. http://www.windturbinestar.com/




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