A wind turbine that uses boundary layers instead of blades to generate power has been patented by Solar Aero, a New Hampshire based not-for-profit scientific research organization. Modeled on the 1913 Tesla steam turbine, the Fuller turbine is virtually silent and completely enclosed, which avoids many of the drawbacks of bladed turbines such as noise, radar interference, visual pollution and wildlife injuries.
Solar Aero's Howard Fuller says the principal of operation is roughly the same as for the Tesla steam turbine.
"Closely-spaced discs trap the motive fluid molecules (in this case air) in a laminar flow adjacent to the disc surface. This provides aerodynamic drag, which imparts force to the disc surface. By using multiple discs, the turbine then provides considerable torque to accelerate the rotation of the central driveshaft, which is directly coupled to an alternator, typically located at the base of a tower, or alternatively co-located on a rooftop."
The turbine is likely to have a cut-in speed of about 3.5 knots and optimum speed is about 20 knots and near transparency to radar microwave transmissions can be achieved with proper construction materials and techniques.
Although currently only in pre-prototype stage, it is anticipated that units would be available in different sizes. The smallest unit would be likely to produce about 5kW at 15 knots.
Solar Aero expects costs to be comparable to coal-fired power generation - around $0.05/kWh. When used in conjunction with a suitable storage device, this should provide reliable, inexpensive power in either residential or commercial applications.
Maintenance costs should be less than for bladed turbines. As the up-tower turbine is supported solely on zero maintenance magnetic bearings, there will be no friction to impede acceleration and no routine lubrication required.
Solar Aero is currently completing a full scale prototype. The design will be available for worldwide production licensing following testing.
Contact Solar Aero for further information.