If you’ve always wanted to put a wind turbine on your roof but thought it would be too big or too loud, you’re not alone. The primary challenges in adapting wind turbines for personal use have been to overcome the fact that they are too unwieldy for small buildings and generate too much noise for densely populated areas.  The new Swift turbine, developed by Scottish energy products and solutions company Renewable Devices, overcomes those obstacles with a nearly silent device that has a blade/ring diameter of only seven feet and requires only a few feet of mounting space. (see the Inhabitat story and the product specs)
Wind turbine noise comes from aerodynamic sources (i.e., the air) and mechanical sources (i.e., the turbine assembly). In traditional wind turbine designs, air flowing along the blades and off the ends of the blades generates noise. 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. First, the turbine has a circular diffuser (21) that rings the turbine blades. In operation, when the airflow reaches the ends of the blades, it contacts the diffuser and proceeds in a circumferential path instead of flowing off the ends of blades.
The Swift turbine also has a furling device (50) with tailfins (53, 54).  When the airflow exceeds a certain speed, the furling device rotates the rotor to maintain the direction of the airflow in line with the turbine’s rotational axis. In excessively high winds, the turbine rotor can be rotated out of the airflow altogether. These measures reduce the vibrations of the turbine assembly components.Â
Finally, the Swift turbine has a mounting structure that includes a rubber core to absorb vibrations before they spread upward to the moving parts of the turbine assembly.Â
So the time to put a personal wind turbine on your roof is now. The Swift personal wind turbines, which are being manufactured by Cascade Engineering of Grand Rapids, Michigan, will be commercially available next month.
