Tuesday, June 23, 2009 at 11:47:25 AM - by Jeanne Roberts

One of the bus shelters on the McMaster University campus, located in Hamilton, Ontario, is lit by two solar cells affixed to its roof. But what makes the solar cells unique is the fact that they’re not, obviously, panels.
Instead, they curve, and the curve – which naturally follows the bus shelter’s roof – means not only are they unobtrusive, perhaps even aesthetically pleasing, but that future shelter occupants won’t have to stand in the dark on those long winter evenings. Not only do the curved panels run LED lights, whose output is bright enough to read by, but each fixture uses only 600 milliwatts of power.

The curved panels, located in the shelter on the west side of University Avenue between the John Hodgins Engineering Building and the Life Sciences building, are the brain child of a group of engineering researchers, including Wei Zhang, who used the project to form the basis for his master’s thesis and subsequently went to work in the college’s Department of Engineering Physics.

Julia Zhu, a research technician, Jesika Briones, a master’s of engineering graduate student, also worked on the project, according to engineering professor Adrian Kitai, who helped develop the curved-panel project.
All hope that the prototype will generate interest in the project, an interest that could lead to commercialization, especially among transit companies who offer Internet-based scheduling updates via interactive flat-panel displays at bus shelters.

The ability to bend solar cells to fit curved surfaces is the highlight of the technology, a flexibility achieved by “tiling” a large number of small silicon elements into an array and then mounting them on a flexible sheet and connecting them through a method that remains proprietary. It’s this method that has the student entrepreneurs seeing dollar signs.

The two units at the McMaster University bus shelter are about 35 inches (90 centimeters) long and about 4 inches (10 centimeters) wide. Each strip contains about 700 one-centimeter (.39-inch) square solar cells and generates up to 4.5 watts of power.

Aside from power LEDs, the researchers hope the solar cells can also find other uses, like shelter signage or interactive features.

Scientists at the Pacific Northwest National Laboratory are also working on flexible solar, and a team there has developed its own shingle-like rooftop solar panels which take advantage of flat-panel technology and LED technology to coat thin-film solar in such a way that it resists the elements.