Georgia Tech and PAX Streamline win grant to reduce cost of wind turbines for generating electricity
A technology originally developed to increase lift in aircraft wings and simplify helicopter rotors could help reduce the cost of manufacturing and operating wind turbines.
Supported by a $3 million grant from the Advanced ResearchProjects Agency-Energy -- the federal energy research and developmentorganization also known as ARPA-E -- a two-year research project aimed atadapting circulation control technology to wind turbine blades will beconducted by PAX Streamline, in collaboration with the Georgia Institute ofTechnology.nd speed.
Circulation control techniques use compressed air blown from
slots on the trailing edges of wings or hollow blades to change the aerodynamic
properties of those wings or blades. In
aircraft, circulation control wings improve lift, allowing aircraft to fly at
much lower speeds -- and take off andland in much shorter distances. In helicopter rotor blades, the technique --
also known as the "circulation control rotor" -- simplifies the rotor
and its control system and produces more lift.
"Our goal will be to make generation of electricity
from wind turbines less expensive by eliminating the need for the complex blade
shapes and mechanical control systems used in current turbines," said
Robert J. Englar, principal research engineer at the Georgia Tech ResearchInstitute (GTRI). "Because these
new blades would operate effectively at lower wind speeds, we could potentially
open up new geographic areas to wind turbine use. Together, these advances could significantly
expand the generation of electricity from wind power in the United States."
The ARPA-E project will apply the technique to controlling
the aerodynamic properties of wind turbine blades, which now must be made in
complicated shapes and controlled by complex control mechanisms to extract
optimal power from the wind.
"The speed at which these turbines would begin to
operate will be much lower than with existing blades," said Englar. "Places that wind maps have previously
indicated would not be suitable locations for wind turbines may now be
useful. The blown technology should also
allow safe operation at higher wind speeds and in wind gusts that would cause
existing turbines to be shut down to prevent damage. "
Because they would produce more aerodynamic force, torque
and power than comparable blades, these blown structures being developed by
Georgia Tech and PAX could also allow a reduction in the size of the wind
"If you need a specific amount of wind force and torque
generated by the wind turbine to generate electricity, we could get that force
and torque from a smaller blade area because we'd have more powerful lifting
surfaces," Englar explained.
A major question awaiting study is how much energy will be
required to produce the compressed air the blown blades need to operate. Preliminary studies done by Professor Lakshmi
Sankar in Georgia Tech's School of Aerospace Engineering suggest that wind
turbines with the blown blades could produce 30 to 40 percent more power than
conventional turbines at the same wind speed -- even when the energy required
to produce the compressed air is subtracted from the total energy production.
The new turbine blades will be developed at GTRI's low-speed
wind tunnel research facility located in Cobb
County, north of Atlanta.
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