The Blue Sky Project, U of T’s solar racing team, is getting ready for another season of pushing technological boundaries-and hopefully winning a few races too.
The ambitious and popular endeavour-up to 300 undergraduate and graduate volunteers are involved during each two-year season-is to design and build an efficient solar-powered vehicle for travel at high speeds for long distances. Races are held every two years in Australia (the World Solar Challenge, in which teams race across the outback from Darwin to Adelaide), and in the United States (the American Solar Challenge, where cars travel from Chicago to Los Angeles along Route 66).
The entirely student-run project is responsible for designing and building all aspects of the car, from the aerodynamic outer shell to the electrical circuits to the suspension system. The project receives significant financial support from the university at all levels-from the Faculties of Engineering and Arts and Science, as well as from the dean’s office and the provost’s office. The project gets funding through a 25-cent fee paid by all U of T students, with an additional $4.75 fee from engineering students.
Designing the critical shape of the car body is a matter of finding “the lowest drag body that can support the most number of solar cells perpendicular to the sun’s rays,” says executive team member Jessica van Vliet, a former project manager. Engineering students spend a great deal of time designing and testing the shell’s shape and materials before using Bombardier’s facilities to create the shell, much the same way an aircraft’s parts are built. In fact, the car’s shape, called a manta-ray shape, is very much like an airplane’s wing.
Most of the car’s upper surface is covered in over 3,000 silicon solar cells. Solar cells, also known as photovoltaic cells (literally meaning “light electricity”) convert light energy into electrical current. When light striking the surface of a solar cell has enough energy-that is, it has to be of a certain wavelength-it will knock electrons from the silicon crystal, which then are free to move. This movement of electrons results in an electrical current, which can then be used to power devices such as pocket calculators and solar cars. Solar cells are receiving a lot of attention as an alternative energy source that is environmentally clean and sustainable.
The solar array is capable of powering the car to speeds of 80 km/h on the same amount of energy as required by a typical toaster oven. The car also uses a battery pack to provide power in cloudy conditions. “Our batteries are lithium-ion superpolymer batteries, which are the highest density batteries in the world,” says van Vliet. The batteries, donated by Toronto-based Electrovaya Inc., can power the car for 300 km at highway speeds.
During races, three drivers take turns driving for six hours at a time. The solar car is a proper road vehicle, with turn signals, headlights, taillights, and a rearview camera (mirrors would ruin the body’s aerodynamic shape). Internal sensors keep track of the car’s speed, battery drain, and solar power generation. “All the car data displayed to the driver, and then also processed through a computer and radioed to the support caravan, [where] that data is put into a computer algorithm.” There is also a weather system in the support caravan that will monitor weather conditions, solar conditions, and location. All the data is fed into the strategy algorithm, which will generate the optimal speed for the car.
The solar car design process is long and involved. “To build a solar car takes two years: it takes one year to design and one year to build,” says van Vliet. The first year is spent entirely on design and research of new technologies. New recruits must spend six months in training just to learn enough to contribute. The second year is dedicated to construction. Integrating the various subsystems is “a continual communication process” between all the subteams, says van Vliet.
The current U of T vehicle, called Faust, is the fourth car the team has built. It’s a modified replica of the 2001 season’s car, which was damaged in an accident in 2002. Earlier models, called Blue and Blue II were learning experiences. Blue II won top rookie standing in 1999 at the American Solar Challenge, finishing 20th in a field of 51. This result was unprecedented for a third vehicle built by any team. In 2001, Faust finished 11th at the American Solar Challenge and 14th at the World Solar Challenge.
For van Vliet and her teammates, the solar car project is about more than making cool things with cool technology. “I think it’s important to demonstrate that we have the technology now to build an alternative energy vehicle capable of reaching such amazing speeds that you’re able to ride on the highway,” says van Vliet. In optimal conditions, the solar’s top speed is a breezy 120 km/h.
During promotional drives through Ontario and Quebec, the solar car gets a lot of reaction. “Construction workers will drop their shovels, little kids will chase us on their bikes, people will turn around and tail us. To be able to use technology-today’s technology, which is the important thing-in order to show people that something like this can be done, amazes people to the point of [thinking] ‘maybe I don’t have to buy the same kind of car, maybe we won’t always be running on petroleum.'” The solar car was centrally displayed at the CNE’s National Trade Center during Queen Elizabeth’s Jubilee visit last fall.
Van Vliet doesn’t think that we will all be driving solar cars any time soon. But the advances made in building solar cars over the past 10 or 12 years, especially in aerodynamics, are showing up in designs for consumer hybrid vehicles like the Honda Insight.
Planning for the next race season, in 2005, has already begun. “We have solved all the basic problems inherent to a new team,” says van Vliet. “All it needs now is the best array and the best batteries, and it can win competitions.” The 2005 vehicle will have two seats, in order to “demonstrate applicability for general use,” says van Vliet.
For solar car builders, their product is the culmination of all that technology has to offer. “You have this fantastic machine, you have so many great technologies put together in the most efficient and integrated way possible,” says van Vliet. “I don’t think you’re going to find a more efficiently built vehicle.”
