17 Jun 2002
Dutch researchers hope that solar cells with an efficiency of 24% will help them win the World Solar Challenge.
This year's contestants for World Solar Challenge - a 3010 km solar-powered car race across Australia - are gearing up for the big day on November 18.
"No team has ever used such efficient solar cells on its car," said TUD student Ramon Martinez, leader of the "Alpha Centauri" team. "[Our car] is fitted with 36 solar panels and in theory we should be able to reach a speed of 190km/h."
Called Nuna, the car is powered by dual and triple junction solar cells that consist of either two or three layers of gallium arsenide. The solar cells will also be used in ESA's SMART-1 lunar mission next year.
"Road tests have shown that the cell efficiency is 24%," said Michel Van Baal, a spokesperson for ESA. "In the triple GaAs structure, each layer converts a separate part of the light spectrum into energy. This makes the cells more efficient."
Power point tracking helps to stabilize the power of the cells in poor weather conditions by converting the panels' optimum power into the best voltage to charge the car's battery. The researchers believe that they will be able to travel up to 500 km on a full battery.
The car's cockpit also contains smaller, 32.5 cm by 9.1 cm strips of solar cells. Originally used in the Hubble Space Telescope, the solar panels are now used to power the car's global positioning system for navigation.
"[The navigation system] will help us to select the best racing strategy to gain an advantage over other teams," said Martinez. "For example it will tell us if we should drive away quickly from under cloud cover or save energy."
Keeping within Australian speed limits, the Alpha Centauri team hopes to beat last year's average speed of 90 km/h and complete the race in four days, rather than the usual five.
"Our greatest competition is expected from the Australian Aurora 101 that won the 1999 World Solar Challenge and the car of the Japanese Honda team that has won twice before," added Martinez. "We also have to beat the University of Michigan's solar car, which won the solar car race down Route 66 in July."