If you’ve ever walked through a skyscraper-laden city on a windy day, you know how big buildings can intensify the gales, creating wind tunnels that accelerate the gusts so that they blow off hats and flip up skirts. Now a 3-year-old Akron, Ohio-based startup called Green Energy Technologies wants to use that same wind-tunnel effect to generate small-wind power more efficiently.
The company has developed a 60-kilowatt, five-blade turbine that comes with what it calls a shroud, which looks like a sort of shallow metal funnel. The shroud creates a wind-tunnel effect in front of the blades, amplifying the wind velocity by a factor of two — so that a 5 mph wind that enters the shroud reaches 10 mph by the time it hits the blade — allowing the system to harness even low-speed winds and ultimately produce more electricity from them.
Green Energy claims its WindCube, unveiled last month at the Windpower conference in Chicago and intended for commercial and industrial buildings in urban and suburban locations, can generate power from winds as slow as 5 mph. Over the course of a year, Green Energy says the system can generate 100-130 megawatt-hours — about the same as a traditional 100-foot-tall turbine with blades 50-60 feet in diameter — in places with winds that average 12 mph, says Mark Cironi, president and founder of the company. For context, 12 mph is fairly windy, and is the average wind speed in cities such as Boston, Lubbock, Tex., Fargo, North Dakota, Oklahoma City and Wichita, Kan.
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