This solar car sails on the wind

The latest solar car by the student team from the Delft University of Technology in the Netherlands for the biennial Bridgestone World Solar Challenge in Australia is built in such a way that it ‘sails’ on the wind.

The Bridgestone World Solar Challenge is a multiday race of 3000 kilometres (1864 miles) through the outback of Australia. Solar race teams from all around the world participate, each with a car designed and built by students.

The new solar car, dubbed NunaX, is the smallest and lightest solar car ever. To save weight, each part of the car has been redesigned. Sometimes other raw materials were used, some parts have just been made lighter by removing as much material as possible.

The car is covered in gallium solar cells, the kind that is usually used in space. These are much more efficient than the more common silicon solar cells commonly found on roofs. Rather than using glass to protect the cells, the team has provided them with a coating of their own, to save weight. The coating contains prisms to ensure that light is directed in a 90 degree angle on the cells.

The most innovative part of the car, however, is its aerodynamic shape. The race track is mostly a straight line, and the wind usually comes from the same side. In the previous race, the students found that their car was helped by that wind. This year, the team designed the car specifically to make use of wind energy. The canopy and wheel rims have been shaped in such a way that the car gets a little extra push with side wind.

The car is streamlined in such a way that a side mirror of a normal car has more aerodynamic drag than the entire NuanX.

Of the 10 races that have been held, a team from Delft University of Technology has come in first 7 times and second twice. The team is sponsored by energy company Vattenfall (formerly Nuon).

Photo: Vattenfall