Thursday, July 12, 2007

Cleveland State: Harnessing the Wind as an Energy Source

The University is still waiting for some legal issues to be resolved, but engineering is still underway for the a new Wind Spire to be built, most likely, on the northeastern edge of campus between Payne and Chester.

Here is a recent article from CSU:

Harnessing the Wind as an Energy Source

Tower of Power

Remember the infamous summer of 2003 blackout? Throughout the northeastern United States, millions were left without critical electric and telecommunication service, and Northeast Ohio suffered the shame of having the problem traced right to its own backyard.

The good news is that the solution may be right in our own backyard, too — at Cleveland State University, in the form of a wind tower designed by associate professor of mechanical engineering Majid Rashidi. Although still a prototype, the elegant helical (spiral) tower has the potential to blow Northeast Ohio towards a bright new future in wind energy.

Interest in wind turbines on Lake Erie is steadily growing, and area leaders think Northeast Ohio can become a world leader in alternative energy development, spurring jobs and research. That’s good news to Dr. Rashidi, a specialist in machine design.

“The helical wind harnessing system of CSU is not a competitor of the large-scale, conventional windmills that are intended for Lake Erie,” he notes. “Our system complements the conventional giant windmills for urban use.”

Unlike traditional wind turbines that need lots of open space on land or on water, his design features a helical wind deflector that can be mounted atop a building in an urban area.

“The idea came to me like a flash late one night in the summer of 2005,” he recalls. “An Ohio-based company had a 1996 patent it was trying to develop, and I told company officials it was not cost effective and would bankrupt them.”

Instead, he offered to invent something to meet the firm’s needs. His cutting-edge structure looks like a giant corkscrew. Once built, it could have just two turns with four electric generators (two mounted within each turn), or it could be a 10-turn helix with 20 electric generators. The design in its current configuration could produce up to about 300 kilowatts of electricity. Dr. Rashidi is working on the design to increase the power rating to 0.5 megawatts of electricity, while reducing the spire’s weight and manufacturing costs.

“The operating principle of this system is based on air velocity amplification,” Dr. Rashidi explains. “When air or any fluid flows onto and around a structure, the flow stream lines assume a velocity profile according to the shape of the structure. As a result, the flow velocity may be amplified at certain locations near the structure.

“On the other hand, the energy carried by the wind at any particular wind speed is a function of cubic power of its velocity,” he adds. “Therefore, a gain factor of 2 in wind velocity yields a wind energy gain factor of 2x2x2 = 8.”

Dr. Rashidi envisions a lightweight structure that puts his tower ahead of other urban wind harnessing designs. High manufacturing costs and technical problems with traditional designs have kept wind energy restricted to areas outside of cities; high maintenance costs and ineffective energy conversion add to the problem. For example, in a typical windmill system, large blades run at a relatively low speed and require a gearbox to speed up the blade. The gearbox, connected to an electric generator system, is prone to frequent costly maintenance and failures.

But Dr. Rashidi’s design eliminates the gearbox and directly couples the blades to new kinds of electric generators that are available off the shelf and are more cost efficient. In addition, the tower would store energy via hydrogen fuel cells, providing energy for peak and emergency times. Currently, when electrical energy is produced, it is used almost immediately with little residual energy capable of being stored.

Another benefit of Dr. Rashidi’s design is that the individual panels that make up the spire structure would make it easier to transport.

Dr. Rashidi has applied for United States and international patents for his invention. Cleveland State plans to construct the first prototype, proof-of-concept unit of this design and mount it atop a campus building, perhaps the four-story maintenance building.

“I’m in almost daily meetings with the University Architect’s Office, and we have received $400,000 in state appropriations to mount the tower, as well as $150,000 from the Ohio Department of Development,” Dr. Rashidi says. He calculates that the tower will boost generator power to six to eight times more electricity than stand-alone generators of the same size.

Dr. Rashidi’s wind tower can be a huge asset to homes, city streets, hospitals, public spaces and secured areas — any place that relies on dependable power.

“Everyone at the University, from the president on down, has been very supportive,” Dr. Rashidi says. “It’s exciting to realize that work being done at Cleveland State may help solve a global problem.”