On the subject of alternative energy transportation -
Dutchmen Win Solar Challenge
spectrum.ieee.org
ADELAIDE, AUSTRALIA, Thursday, 22 November–In a dazzling finale to the world’s preeminent solar car race, the first two entries across the finish line–built by students and engineers working on their own time–beat the record set five years ago by a car backed by the full corporate muscle of Honda. The Dutch team Alpha Centauri had never raced before, but even so won the 3000-km race from Darwin to Adelaide, coming in 34 minutes ahead of the defending champion, the Aurora Vehicle Association, based in Melbourne, Australia.
Alpha’s vehicle, named Nuna, came in first in the field of 38 entries by finishing in the record time of 32 hours, 39 minutes, and with a new high in average speed of 91.81 km/h. In an astounding final push, the Alpha team traveled 830 km during the last day of the race, shattering the one-day record set by the Honda Dream racer on the last day of the 1996 race, when it traveled 803 km. To secure second-place honors, the Aurora Vehicle Association’s Aurora averaged 90.26 km/h. Honda’s numbers in 1996 were 33 hours, 32 minutes, from start to finish and an average speed of 89.76 km/h. The third-place finisher this year was the University of Michigan, whose M-Pulse vehicle came in at 34 hours, 19 minutes.
Nuna pulled in first thanks in large part to the field’s most efficient array of solar cells. The Alpha Centauri team leader, Wubbo Ockels, told IEEE Spectrum that the car’s array was 24 percent efficient, meaning that it converted 24 percent of the radiant solar energy falling on it into electric power for the car’s battery pack and motor. The triple-junction gallium-arsenide cells, manufactured by Emcore, were first-quality space-grade cells. In comparison, the Aurora and Michigan teams said their arrays had efficiencies of about 21 and 19 percent, respectively; like many of the other competitors, they were using cells not quite good enough for use on satellites. snip.....
Parts do not come cheaply
Although Aurora’s array was not as efficient as Nuna’s, the Australian team was not without its own technological ace-in-the hole: an electric motor that was 98 percent efficient. The motor, designed by Australia’s National Commonwealth Science and Industrial Research Organization, had an advanced stator utilizing exotic rare-earth magnets and an unusual shape to generate magnetic fields of up to 15 tesla and forces of up to a metric ton. The stator alone cost more than US $40 000, according to Sorin Ionascu, a member of the Aurora team and a graduate student at the University of Melbourne.
Still, this was dwarfed by the cost of the Nuna solar array, which unconfirmed reports put at about US $1.3 million. The rumors prompted some grumbling after the race about the well-financed newcomer. "You can’t beat that kind of money," Ionascu complained.
Nevertheless, new friendships were springing up all over as the intense rivalries faded in the post-race euphoria in Adelaide. As they drank champagne in the late-spring South Australian sun and cheered on other teams coming across the finish line, some crew members observed an old rowing tradition by exchanging team shirts. "I can’t believe it’s over," said Blair Lorimer, of the Michigan team. "I kind of wish it were still going on." |
