Empowered by the sun

Engineering students unveil new-generation solar car

By Judy Woodward and Rhonda Zurn

May 9, 2008

It was a dark hour for Adam Shea, a junior majoring in electrical engineering. Last year, the Solar Vehicle Project was in jeopardy.

For nearly two decades, the project had given dedicated teams of engineering and science undergraduate students in the University of Minnesota's Institute of Technology an opportunity to race across North America in a James Bond-style fantasy vehicle that they designed, powered by the amount of energy it takes to fuel a couple of hair dryers.

For Shea and nearly three dozen teammates, the project, which culminates every two years in the North American Solar Challenge, was to be the crown of their undergraduate career.

"It's a lot of work, but it's the most fun, and it's the biggest project undergraduates can get into," Shea says.

Then without warning, last year the government withdrew its support for the race--the 2007 competition was cancelled. In 2005, the University team had placed second--by only 11 minutes. Was it now to be shut out of all hope for the winner's circle?

"It's a lot of work, but it's the most fun, and it's the biggest project undergraduates can get into," Shea says.

Looking back on those tumultuous days, Shea reflects--only partly in jest--"When I thought the solar car was doomed, I didn't know what I was going to do with my life."

Solar vehicle returns

Happily for the long-range life plans of Shea and his fellow students, help was at hand. At the 11th hour, the Toyota Corporation stepped forward to sponsor the challenge. The University was back in the race.

Project manager Sam Lenius, a senior majoring in electrical engineering, jokes about how he announced the revival to the group. "What are you doing this weekend? Nothing? Not nothing! Solar car is back!"

Since then, the team of about 30 students has spent an estimated 30,000-45,000 hours working on the car.

Solar car video

Watch a video of the solar car that includes comments from student team members.

Centaurus will be competing in the 2008 North American Solar Challenge, a 2,400-mile race from Dallas to Calgary, Alberta, July 13-22. The University of Minnesota is one of only 26 international teams competing in designing, building, and driving a solar-powered car in this year's event.

"Competitions like these are an important way to train the next generation of renewable-energy experts," says Dick Hemmingsen, director of the Initiative for Renewable Energy and the Environment. He stresses the benefit to the University of involving undergraduates in such complex, multi-faceted projects.

Working on a project like the solar car, says Jacob Hanna, a senior majoring in mechanical engineering, "is a whole lot of fun," but it's also serious business at a University that's known for the excellence of its solar energy research.

An educational experience like no other

The new vehicle is named Centaurus, after the constellation of the same name. Centaurus, team members explain, has design modifications that should make it more comfortable for the driver. For one thing, the driver is able to sit up. With its tiny ventilation slits and narrow, recumbent driver's space, Borealis III--the team's previous vehicle--could reach interior temperatures of 135 degrees.

However, comfort and interior luxury are not the point. This is a racing car, designed to go the distance under power generated entirely by the array of solar cells delicately fixed to its exterior.

Making it possible

Cash donations and in-kind donations of parts and materials made the U's solar car possible.

Major sponsors of the Solar Vehicle Project include 3M, Advanced Circuits, AIRTech International, Caterpillar, Digi-key, DuPont, EMJ Metals, Empro Shunts, Freescale Semiconductor, Future Lighting Solutions, General Plastics, Lockheed Martin, Magnetics Inc., Noritake Inc., Northwest Airlines, PaR Systems, Philips, Remmele Engineering, Sal Clear, Stevens Urethane, University of Minnesota Institute on the Environment, University of Minnesota Initiative for Renewable Energy and the Environment, and Vicor.

"The trick is to regulate the speed to maximize the benefits of the available sunlight," explains Lenius. A cloudy day in Minnesota is going to provide less charge than the glaring sun of the Texas plains, and the savvy team must know how to deal with both. Otherwise, the vehicle might face the ultimate humiliation--a dead battery in the middle of the race.

Weather forecasting is only one of the skills team members must master. Students are divided into four subgroups: aerodynamics, electrical design, mechanical systems and, of course, the design and fabrication of the all-important solar array.

Members of the solar car team say the education they get by working as part of the Solar Vehicle Project provides experiences they can't get in their classes. "The interdisciplinary integrations," are what Hanna calls the most useful part of the project. "Learning to organize a group of people and manage a timeline."

For Emily Johnston, a senior majoring in electrical engineering, it's the team effort. "It's really cool to be part of a process," she said, "I enjoy problem solving in groups."

Watching "power flow" the first time he tested solar cells delighted Ryan Maclachlan, a junior majoring in mechanical engineering, but he was surprised by something else. "The scope of interactions with people," he says. "It doesn't seem that there should be that much talk-but there is."

For project manager Lenius, working on the Solar Vehicle Project has given him an unexpected benefit. Not only has he has improved his technical savvy; he has also improved his social skills.

"I used to be introverted and awkward," he says in mock humility. Then he squares his shoulders and, to the obvious enjoyment of his fellow students, transforms himself into a parody of a polished young professional as he intones, "My leadership experience in the solar car project has greatly improved my social skills and ability to lead people."

The team also has the never-failing pleasure of watching the reactions of bystanders when they take their odd-looking vehicle out in public. They can draw a crowd in minutes, but the gold standard, says Nick Simon, a junior majoring in aerospace engineering, is seeing "how many kids fall off their skateboards."

Jeff Hammer, an instructor in the Department of Aerospace Engineering and Mechanics, became the faculty advisor for the Solar Vehicle Project this year after long-time advisor and mechanical engineering professor Patrick Starr retired.

"It's amazing to see how the students mature when they assume the responsibilities that go with the project," Hammer says. "They beat down my door wanting to learn. It's wonderful to teach under those conditions."

Adapted from a story in the Spring/Summer 2008 issue of Inventing Tomorrow, a publication of the University of Minnesota's Institute of Technology.