Published on July 14th, 2011 | by Andrew6
CalTech Vertical Axis Wind Turbines Boost Wind Farm Power Efficiency 10x
Researchers at CalTech have found a way to increase the power output of wind farms at least 10x simply by optimizing the placement of wind turbines in a farm to “maximize its energy collecting efficiency at heights closer to the ground.” Besides significantly enhancing the economics of wind farms, the design approach would also significantly reduce land use requirements, environmental impacts and threats to flying wildlife.
Inspired by the movement of schooling fish and the much noted inefficiencies inherent in wind turbines generally speaking, CalTech’s research team, led by John Dabiri, has been testing its theory at the Field Laboratory for Optimized Wind Energy (FLOWE), an experimental wind farm in the California desert.
Swimming against the tide of the industry trend of building larger, taller horizontal axis turbines and larger wind farms, Dabiri and team have been working with smaller, vertical axis wind turbines (VAWTs) that take advantage of typically lower wind velocities at lower altitudes. VAWTs have a much smaller footprint than the much more common horizontal axis counterparts and can be spaced much closer together. They are much slimmer and aren’t nearly as tall.
“The global wind power available 30 feet off the ground is greater than the world’s electricity usage, several times over,” Dabiri was quoted as saying in this Physorg news report.
Testing a wind farm configuration made up of 24, 10-meter tall VAWTs with 1.2 meter diameters spaced about 5 meters apart, the research team generated 21-47 watts per square meter of land. A HAWT wind farm of the same size would typically generate just to 2-3 watts per square meter.
Minimizing the space between VAWTs and having each turbine turn in the opposite direction of its neighbors minimized the amount of drag on each, enabled them to spin faster, and maximized the power efficiency of the farm as a whole.
Next up for Dabiri and the CalTech team are to scale up the field trial and improve on “off-the-shelf wind turbine designs for the pilot study,” according to the Physorg article.
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