• Shine on

    • Image credit: Advanced Energy Foundation
    • Back on the road with in the annual World Solar Challeenge.
    • Sun-powered electric racers.
    • Delft University in the Netherlands has taken various generations of its entrant, Nuna to victory in several World Challenges.
    • The mighty modest range from Michigan state university
    • An electric car based on an Australian design
    Date:31 August 2008 Tags:, , , , , , , ,

    With a whine and a whoosh, the solar challenge comes to South Africa

    For nearly two decades, solar car teams have made the annual pilgrimage to Australia's wide open spaces to push the boundaries of sun-racer design. The World Solar Challenge has become the test bed – and the graveyard – of more than a few solar reputations.

    It's taken a while, but finally somebody has realised that South Africa has plenty of wide open spaces of its own.

    Come September, don't be surprised to see little convoys on our major roads, escorting what look like gleaming giantsized cockroaches on wheels.

    The 4 175 km South African Solar Challenge runs from September 28 to October 8. Having set off from Midrand on September 28, competitors drawn from various parts of the world will have 9 hours a day in which to drive their lowslung aerodynamic sunracers. When they reach the finishing point – the Innovation Hub, Pretoria – a little over a fortnight later, they'll have visited most of the country's major centres.

    However, we won't be seeing solarpowered commuter cars scuttling along our freeways anytime soon. "That's not what it's about. It's about maximising efficiencies and pushing the envelope for solar and electric power," says Jordaan.

    As head of the Advanced Energy Foundation, Jordaan also hopes that the South African version of the challenge will spark interest in electric cars in general (see "Commuting by wire").

    A team effort
    Teams will have to build their own cars, design their own engineering systems and race those same machines through the most demanding terrain that solar cars have ever seen, Jordaan says.

    The cars all have huge solar arrays (see "By the rules") feeding batteries that drive electric motors.

    But of course, the car is just part – albeit an important part – of a team. The full team complement will include, besides the driver, support vehicles front and rear (in radio communication) and technicians monitoring and analysing masses of data received from the solar car by telemetry.

    Among the overseas teams that have confirmed entry are Tokai University of Japan, which has taken part in eight international races since 1994; MIT, from the USA; Delhi College of Engineering from India; and the NSIT Solar Car Team, also from India.

    Several others, among them the Netherlands' multiple world champion Nuna, are being courted.

    "We're negotiating with the Nuna team, but it seems unlikely they'll come if we can't attract other competitive teams," Jordaan says.

    Shipping costs and a local support team are what's holding most of them back. "We've tried to pair visiting university teams with local universities to provide support," says Jordaan.

    The requirements of Solar Fern Racing of New Zealand are rather more specific: "They need a new set of solar panels to use while racing. If we can secure this they will come, but they also want a local support crew."

    Two local corporate teams are confirmed. The Oelsner Group of Cape Town, known energy projects (notably the Darling wind farm) and Eco-Zone of Johannesburg. A private team from Centurion had earlier confirmed its participation, but after the withdrawal of its main sponsor, was battling to get its entry prepared.

    Organisations that have lent their seal of approval to the Challenge include the Department of Science and Technology, the International Solarcar Federation (ISF), World Wildlife Fund (WWF), Federation Internationale de l'Automobile (FIA), Motorsport South Africa and the National Energy Efficiency Agency.

    Tough just got tougher
    The World Solar Challenge is described on its web site as the ultimate challenge in sustainable energy. The challenge is to design and build a car capable of crossing Australia using only sunlight as fuel. However although based on the World's, the South African event nevertheless has important differences.

    For one thing, it's a lot longer, and there's a lot more climbing.

    "In South Africa, we are different in a couple of ways," says Jordaan. "At the World Challenge in Australia, over the total distance of 3 000 km they climb from sea level to 700 m at Darwin and then Adelaide.

    "In South Africa, we'll cover 4 175 km, starting at 1 800 m. From there it's down to sea level at Cape Town, then back up to 1 800 m at Kokstad, and once again down to sea level at Durban and finally back to 1 800 m in Pretoria."

    In short, the Australian event has 6 km of vertical climbing; South Africa will have 33 km of vertical climb.

    Having dealt with the terrain, competitors will face another challenge: the weather. Mild springtime in the Highveld will be rather different from the cool and blustery (possibly wet, too) Western Cape or warm, humid KwaZulu-Natal.

    It's how you use it
    All of these conditions will significantly impact on the single most important part of solar racing – battery management

    “Algorithms. Strategy. That is what solar races are about,” Jordaan says. “They are won or lost on the method and strategy that you use.”

    It’s not necessarily about whether the design is cutting-edge or high-tech.

    “We always tell the guys… first, have a mechanically reliable car. You have to have a good technology.”

    Last year’s winner, as it has been for the past several years, was Nuna of Delft University in the Netherlands. Nuna finished two hours ahead of the secondplaced team, using advanced, highefficiency – and hugely expensive – thinfilm gallium arsenide cells. Cherry-picking cells produced even better efficiencies than the typical 30 per cent, Jordaan believes (“There were claims of a 36 per cent average efficiency”.)

    Third-placed Aurora, in contrast, used thoroughly conventional silicon cells whose efficiency was just more than half that of the winners’. “Others had vastly better technology. But the reason Aurora could be competitive, even with that disadvantage, was that they had a better strategy and really good aerodynamics.”

    Jordaan also expects South Africa to be a lot tougher than Australia in other ways. “In Australia, the lead cars were complaining that for the last 1 500 km they were running at the speed limit. They were pretty much running at 110 km/h.

    “Strategically, South Africa will be far more complex.”

    He concedes that there will be plenty of unknowns. “It’s the first time. Nobody knows what it is going to be like. Some people have complained that it’s too tough.

    “But, for goodness’ sake, it’s a challenge.” There’s one thing of which he has no doubt, though: “It will set a whole new level for solar racing.”

    • If you’d like to find out more about the Solar Challenge, or if you’d like to find out about offering your services as a volunteer, visit www.solarchallenge.org.za.

    Contact Winstone Jordaan on 083 284 7747 e-mail winstone@solarchallenge.org.za or Johan Viljoen on 082 561 6846 e-mail johan@solarchallenge.org.za

    Racing by the rules
    ? Maximum dimensions of a competition solar car, according to FIA regulations: 4 m long by 1,8 wide and 1,6 high.
    ? Minimum weight: 100 kg
    ? Maximum allowed solar cell surface: 6 m2
    ? Drivers complement: minimum 2, maximum 4
    ? Normal road rules apply; brakes, lighting and reverse gear are required
    ? For drivers lighter than 80 kg, ballast may be added
    ? Battery capacity is determined according to type (for instance, Li-ion). It’s equivalent to about 5 kW for endurance races.
    ? At compulsory half-hour control stops, offi cials will check that the car is still roadworthy and that the driver is well.

    Communicating by wire
    If Winstone Jordaan has his way, we'll be driving to work and back quietly, cleanly and cheaply in electric cars. His proposed car, based on an Australian design, will be built for a purpose: the commute.

    "We've identified the ideal car; it’s just not been industrialised yet,” says Jordaan.

    “We are looking to build a commuter car, with a range of 150 to 200 km. The thing is, statistically, 80 per cent of driving involves one person and another 15 per cent two people.” With that in mind, they’re planning a 3-wheeler with its single wheel at the rear. The occupants would sit one behind the other. This layout has significant stability benefits over a trike layout with the single wheel up front.

    “The prototype car (above) that’s been built weighs 340 kg, and does about 120 km on a charge. We are targeting 280 kg. If we achieve 280, the range is simple.”

    He estimates that it would be possible to cut 13 kg on the motor alone.

    Besides having a novel drive system and lithium-polymer batteries, the car would use an innovative financing model based on leasing. “We’ll emphasis flexibility. The best comparison I can make at this stage is to liken it to fractional ownership.”

    Here’s an example of how it might work: if you were based in Johannesburg, say, and travelled to Durban on business, you could obtain another vehicle to drive while out of town. Meanwhile, back home your own vehicle could be in use as a “pool” car.

    Estimated cost at this stage is less than R3 000 a month, and will include everything from tyres to windscreen wipers and batteries to insurance. He is planning to have a hundred of his cars being test-driven by the middle of 2010..

    “We have already got a security company interested.”

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