A wind turbine that spins in a spherical formation increases efficiency and reduces noise, according to its Dutch developer, Home Energy. The Energy Ball replaces the traditional rotors of a wind turbine with an egg whisk-shaped structure designed to funnel wind within the turbine's blades. Erik Aurik, Home Energy mar-keting manager, said the technology works on the Venturi effect, which is usually associated with the drop in pressure that results when a gas or fluid flows through a constricted space at speed. The spherical ball uses that principle by constricting the wind, so causing the pressure inside the ball to drop. The low pressure means the air flowing around the ball is sucked in and this helps turn the rotor blades. The rotor blades use more wind and the turbine has a higher aerodynamic efficiency compared with conventional wind-turbine designs of the same diameter, said Aurik. Most modern wind turbines are designed with three flat blades and the turbine's head moves in the direction of the wind, using a computer-controlled system. The tips of the blades, which can reach up to six times the speed of the wind, make perpendicularrnslices through the air, causing a swishing sound that some people find annoying. The Energy Ball rotors are bent around in a ball shape so they primarily move parallel to the wind, making it quieter than conventional wind turbines, said Aurik. Thernnoise of the Energy Bali will never exceed the wind sounds.'rnIt can also operate at very low wind speeds. 'The turbines will start turning at 2m/s and the Energy Ball can start generating electricity at 3m/s,' he said.
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