OSU Engineer Develops New Rooftop “Micro” Wind Turbine for Green Buildings

Story Posted: Tue, Dec 19, 2006

By Rachel Partin

CORVALLIS, Ore. – An Oregon State University engineering professor has helped design a new “micro” wind turbine that can be mounted in rows along the edges of building rooftops to generate “green” electricity.

The new small-scale turbine design could revolutionize the wind power industry, enabling power generation from wind in urban and suburban settings instead of only from traditional wind farms of towering turbines erected in rural areas.

Stel Walker, who was a graduate student at OSU in the 1970s when OSU was one of only two universities in the U.S. doing wind energy research, is now assistant head of OSU’s Department of Mechanical Engineering and director of the university’s Energy Resources Research Laboratory (ERRL). Walker helped pioneer wind energy research at OSU by creating computerized aerodynamic performance design analyses of wind turbines and maintaining the foremost wind database in the nation.

Now a leading design consultant in the wind energy industry, Walker works with California-based AeroVironment, Inc., the manufacturer of the new wind turbine, which the company calls “Architectural Wind.”

“There are only a few wind turbine manufacturers in the U.S., and they’ve been telling city planners, architects and building owners for years that they haven’t designed their wind turbines to be placed on or around buildings,” said co-inventor Tom Zambrano of AeroVironment. “But no one understands wind resources better than OSU, and Stel Walker says the wind in the Pacific Northwest doesn’t stop at city lines.”

Walker helped the company envision a small, quiet and architecturally pleasing wind turbine designed to attach to a track running along the perimeter of a roofline, similar to the way lighting is attached to tracks. The number of turbines mounted to the track can vary, depending on power needs, and the size and design of the building.

“This is an example of Stel’s creativity and innovation capacity,” Zambrano said.

When mounted on the parapet of a building, the new turbines combine architectural, aerodynamic and mechanical engineering to collect more wind and produce more energy than previously thought possible.

“When wind senses an object in its path, such as a building, its velocity can increase as it shoots up and over the roofline,” Walker said. “This depends, however, on the architectural design of the building and landscaping design of the surrounding property. The new turbines are designed to be installed on existing commercial building designs and can work with other renewable energy technologies such as photovoltaic.”

Customers can start with as few as six kilowatts, about 10 of the 4-foot turbines, then add more as power needs increase. Some buildings, such as very large warehouses and distribution centers, may be able to accommodate 100 or more turbines. Banks of the new wind turbines, which are called “Architectural Wind,” have already been installed on buildings in California and elsewhere.

Although the new turbines are designed primarily for use on commercial buildings, micro turbines could one day be used in residential applications, officials say. As green building technologies are gaining acceptance, building owners and designers want buildings to clearly show that they employ these technologies. Unlike many green technologies that are generally not visible, such as solar panels, the new wind turbines are designed to be highly visible, yet also blend in architecturally.

Zambrano and many other scientists who have been involved in wind energy research since the early 1970s view OSU’s research as critical to the current world wide acceptance of wind energy.

Wind and other forms of alternative energy production are an integral part of “green” building design, which Walker and OSU are committed to supporting.

The wind power industry started at OSU when Walker and former OSU professors Wendell Hewson, Robert Wilson and Robert Thresher began wind research in 1971. At the time, only one other institution, the University of Massachusetts, was starting similar research.

The program at OSU began by first developing aerodynamics for horizontal axis wind turbines, then creating structural design analysis codes for structural engineering.

“Our team created all of the first computer models for wind energy that are still used today,” Wilson said.

In the ensuing 35 years, Walker has become a highly respected wind energy expert.

“Stel has been successful in every aspect of wind energy design, and with his help, wind energy production has gone from a research and development interest to a Fortune 500 concern,” Wilson said.

In 2004, Walker was presented the Academic Achievement Award by the American Wind Energy Association at the Global Windpower Conference.

Information about current and historical wind levels in and around the Pacific Northwest is stored in a database that Walker and his colleagues at OSU began developing for the Bonneville Power Administration (BPA) in the mid 1970’s. This database was the first of its kind and is the longest running record of wind levels in the nation for wind energy purposes.

Currently, OSU supplies information from this database to other research universities across the country, as well as to wind energy developers, residents, communities and businesses interested in developing wind energy in the region.

The database was started in order to determine the viability of wind energy production at a particular location. Because it costs hundreds of millions of dollars to develop a wind farm, the BPA and other interested customers must make an economic analysis of the profitability of a potential site. Similarly, residential and other commercial property owners can use the database to help determine if wind energy is a practical option for them.

Today, anemometers are available for loan through OSU’s Anemometer Loan Program, sponsored by the Energy Trust of Oregon, for home use and small-scale wind energy development.

Walker graduated from OSU with a B.S. degree in Aerospace Engineering in 1970 and completed his Ph.D. in Mechanical Engineering in 1976 after serving as an officer in the U.S. Air Force. He has authored or co-authored more than 200 publications.