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Flexible solar strips light up campus bus shelter


August 19, 2009
by Plant Staff

New flexible solar cell technology developed by a group of engineering researchers at McMaster University in Hamilton will ensure night-time transit users won’t have to stand in the dark at a campus bus shelter. But the researchers also hope the prototype will lead to commercialization of the new technology.

Flexible solar cell technology lights up a McMaster University campus bus shelter at night.
PHOTO: MCMASTER UNIVERSITY

The bus shelter is located on the west side of University Avenue between the John Hodgins Engineering Building and the Life Sciences Building.

“Our goal is to provide a clean, affordable power source for bus shelters that will let transit companies run Internet-based scheduling updates,” said Adrian Kitai, a professor of engineering physics at McMaster who guided the project. “The solar technology can also be used to light up bus shelter signage and provide lighting for general safety.”

The flexible solar cell project started as a master’s thesis for Wei Zhang, who subsequently worked as an engineer in the Department of Engineering Physics. Julia Zhu, a research technician in the department, and Jesika Briones, a master’s engineering entrepreneurship and innovation graduate, also helped develop the initiative.

One of the main features of the technology is its ability to bend the solar cells to fit the curved roof of the bus shelter. Flexibility is achieved by tiling a large number of small silicon elements into an array, mounting them onto a flexible sheet, and connecting them through a proprietary method.

The two solar strips installed on the bus shelter are about 90 centimetres long and 12 centimetres wide. Each strip has 720 one-centimetre square solar cells and generates up to 4.5 watts of power.

A solar strip was mounted at each end of the bus shelter roof and connected to two energy-efficient, multi-LED, light fixtures. Each light fixture uses only 600 milliwatts of power and produces about the same light output as a three watt regular tungsten bulb or what a small night light would use, and the lights are bright enough for easy reading.

The solar cells capture sunlight during the day and convert it to electricity to recharge batteries located in each lighting unit, and they hold enough charge to light the shelter for the better part of a night.