[amor de cosmos]

Phil McKenna
December 3, 2012
Ducted Wind Turbines: An Energy Game Changer?
Ducted turbine promises significant advances but delivery remains to be seen.

When it comes to wind power, unconventional schemes to boost power and cut costs have never been wanting. Quiet Revolution offers a vertical axis turbine that looks more like a blender than a power generation device. WhalePower proposes mimicking on turbine blades the tubercles found on whale fins to increase power production. Meanwhile Altaeros Energies is developing a flying donut to harness increased wind speeds found at higher elevations.

Earlier this month SheerWind, a wind power startup based in Chaska, Minnesota, added a new design, INVELOX, to the list. INVELOX, short for “increasing the velocity of wind” is a ducted turbine that looks a bit like a giant funnel sitting on top of an equally large periscope. The ductwork is designed to capture wind from any direction, increase its speed and concentrate the moving airflow before passing it through a relatively small turbine at ground level.

It’s an interesting concept that attempts to address a number of challenges facing conventional wind turbines. The power produced by a wind turbine increases with the cube of the wind speed so any increase in speed could offer a significant power boost. Increasing wind speed also reduces the cut in speed, or the minimum wind speed required to begin generating power. SheerWind officials say that by speeding up the wind they can boost power output by 280 percent and reduce the cut in speed by 80 percent to a wind speed of 2 miles per hour.

http://www.technologyreview.com/view...-game-changer/