IfÂ you’ve always wantedÂ to put a wind turbine on your roof but thoughtÂ it would be tooÂ big or too loud, you’re not alone.Â The primary challenges in adapting wind turbines for personal useÂ have been to overcome the fact that they areÂ tooÂ unwieldyÂ for small buildings and generate too much noise forÂ densely populated areas.Â Â The newÂ SwiftÂ turbine,Â developed byÂ ScottishÂ energy products and solutions company Renewable Devices, overcomes those obstacles with a nearly silent deviceÂ that has a blade/ring diameter of only seven feet andÂ requires only a few feet of mounting space. (see theÂ Inhabitat storyÂ and the product specs)
Wind turbine noise comes from aerodynamic sources (i.e., the air) and mechanical sources (i.e., the turbine assembly).Â In traditional wind turbine designs, air flowing along the blades and off the endsÂ of the blades generates noise.Â Additional noise can be caused by vibration of the turbine assembly during high winds and turbulent airflow common in urban areas.Â
The new turbine design covered by Renewable Devices’ U.S. Patent Application Pub. No. 2006/0244264 addresses these problems in several ways.Â First, the turbineÂ has a circular diffuser (21)Â that rings the turbine blades.Â In operation, when the airflow reaches the ends of the blades, itÂ contacts the diffuser and proceeds in aÂ circumferential path instead of flowing off the ends of blades.
The Swift turbine also has a furling device (50) with tailfins (53, 54).Â Â When the airflow exceeds a certain speed, theÂ furling deviceÂ rotates the rotor to maintain the direction of the airflow in line with the turbine’s rotational axis.Â In excessively high winds, the turbine rotor can be rotated out of the airflow altogether.Â These measuresÂ reduce the vibrations of the turbine assembly components.Â
Finally, theÂ Swift turbine has a mounting structure that includes a rubber core to absorb vibrationsÂ before they spreadÂ upward to theÂ movingÂ parts of the turbine assembly.Â
So the timeÂ to put aÂ personal wind turbine on your roof is now.Â TheÂ Swift personal wind turbines, whichÂ are being manufactured byÂ Cascade EngineeringÂ of Grand Rapids, Michigan, will be commercially available next month.