Green Patent Blog

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. 

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. 

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. 

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.

Who would have thought you could get patent protection for putting a sail on a ship?  It seems the novelty was lost in the days of Columbus.  But that’s what German company SkySails has done.  SkySails’ computer-controlled kites can reduce fuel use in large freight tankers by 10-35% and are the subject of a recently-issued patent.  Both EcoGeek and Matter Network have reported on the kites, which span more than 1700 square feet and fly at a height of 600-1,000 feet to take advantage of stronger and more stable winds.

U.S. Patent No. 7,287,481 covers an aerodynamic kite for driving watercraft.  The device, which the patent calls an “aerodynamic profile element,” alleviates certain problems inherent in using large kites, such as control of the kite, unpacking and packing the kite (”unreefing” and “reefing”) and launch and retrieval procedures.  The kite has an upper layer and a lower layer with four openings for air intake between the two layers arranged around the horizontal longitudinal axis of the kite.  Air enters the openings and fills the internal space between the upper and lower layers.  A stiff kite stick fixed along the longitudinal centerline of the kite provides stabilization.  The stick may be shortened or locked in a particular position for ease of reefing and unreefing.  A gondola at the bottom of the kite connects to a pulling cable that can attach to a watercraft.  The kite has a network of reefing lines that extend to outer fixing points at the outer edges of the kite.

With the fuel savings the SkySails kite provides, it may become a very popular product for cargo ships.  But SkySails isn’t stopping there; it also filed a patent application for a device for converting wind into mechanical energy, which pairs its kites with energy converters.  Perhaps a subject for another post…