Vertical axis versus horizontal axis wind turbines
Date: Tue Jun 24 2014 ; Tags: Wind power
About vertical and horizontal axis wind turbines - orientation is important
I've been seeing horizontal axis wind turbines for so long, that I hadn't even thought about alternative designs. But now that I know the difference, and I see the simplicity of the vertical axis wind turbines, I wonder why there is so much emphasis on the horizontal axis turbines.
But, first, you're probably wondering what the difference is?
Well, the horizontal axis turbines are the "propeller on a stick" design that are what's typically sold and installed. On this page, How wind turbines work, there are several pictures of horizontal axis turbines, plus an in-depth description of their function.
Vertical turbines follow several shapes with the essential characteristic being they can spin no matter the direction of the wind. As the Wind Turbine entry on wikipedia says:
Vertical axis turbines (or VAWTs) have the main rotor shaft running vertically. The main advantages of this arrangement are that the generator and/or gearbox can be placed at the bottom, on or near the ground, so the tower doesn't need to support it, and the fact that the turbine doesn't need to be pointed into the wind. Drawbacks are usually the pulsating torque produced during each revolution, and the difficulty of mounting vertical axis turbines on towers. This means they must operate in the slower, more turbulent air flow near the ground, with lower energy extraction efficiency.
A (very) different kinda wind turbine: describes a turbine called the Aerogenerator that looks like a strange eggbeater. It was designed by Grimshaw, an Architect firm, along with Windpower Ltd.
An interesting twist on wind energy: Discusses a turbine design by Aerotecture, Ltd that's a beautiful spinning sculpture. It is small enough to be integrated with many sorts of building designs, is very quiet, is very easy to install, etc.
Wind Harvest - http://www.windharvest.com/ - is another manufacturer. "Windstar turbines are rugged, easy-to-install and maintain, quiet, low profile, bird-friendly and promise to be among the least expensive per kW machines available when mass production begins."