Budding engineers prepare for the 2012 South African Solar Challenge
By Sean Woods
Oil lubricates the wheels that keep our modern world running. At some stage, though, our dependency on this unsustainable fuel source is going to have to come to an end. Fully aware of the transportation challenges that lie ahead, a multi-disciplinary team of students from the University of Johannesburg is tackling the issue head on. Their objective: to come up with a real-world solution.
But closer to the here and now, these pragmatic boffins-in-the-making have set their sights on a more immediate goal. They intend showcasing their research to date by entering three alternative energy vehicles – one powered by the Sun, one running on hydrogen and the other incorporating a small turbine – into this year’s South African Solar Challenge. They will be competing against other university teams from across the globe.
You only have to fill up your fuel tank on a regular basis and monitor your depleting bank balance to realise how increasing energy costs are coming into conflict with economic growth. It’s a given that non-renewable fossil fuels are going to become more expensive over time. So, too, is the reality that petroleum currently provides about 40 per cent of the world’s energy needs, and that some expect global energy consumption to grow threefold over the next 25 years.
Then there’s that inconvenient truth – global warming – exacerbated by the burning of fossil fuels.
Clearly, something constructive has to be done. The sooner some bright spark comes up with a viable solution, the better. With this in mind, the University of Johannesburg sprang into action. UJ encourages its students to think energy
innovation, sustainable engineering design and manufacturing, and environmental awareness.
What better way to promote this strategy than the biennial South African Solar Challenge?
Masters student Kegan Smith, who heads UJ’s alternative energy vehicle project, explains: “We’ve found that, if you provide people with a challenge, they rise to the occasion. The race is a great platform for exposing our students to real-world issues and deadlines while working on their studies. And, as tackling real-world issues requires a holistic
approach, we have pulled our mechanical, electrical and electronic engineering, industrial design, IT and marketing
departments into the project.”
Students from these various disciplines have come together to design three vehicles, all of which are currently under
construction. Each incorporates a battery bank and an alternative energy source; one uses use solar panels, another is powered by a turbine generator, and the third incorporates a hydrogen fuel cell.
To ensure continuity, the project runs on an overlapping three-year cycle. Each team of students participates in the project for the full three years, from undergraduate to postgraduate level – thus encouraging knowledge transfer and the peer mentoring process. Each vehicle is then tested in a solar challenge event, and then modified and refined by the next generation of students.
How it all began
When UJ started the development of its first hybrid vehicle – the BAR-1 – its sole intended purpose was as a technology
demonstrator for masters students. The 2010 Solar Challenge was a tantalising carrot, five months away. But no one actually expected it to be completed in time. “Our lecturers were convinced we wouldn’t succeed, but they didn’t tell us it was impossible – they’re like that,” laughs Smith.
To everyone’s surprise, they completed the BAR-1 on time. What’s more, they won the Adventure class and came in at
second place overall.
“It incorporated much more than you’d find in a normal car,” says Smith. “Its robotic system, which I like to call ‘the
next step to cruise control’, used lasers and actuators on the steering wheel and pedals to faithfully follow a car driving in
front of it. Understandably, we didn’t use it on the race for safety reasons – anyway, it was a work in progress.”
To get it moving, Smith and his fellow students combined a Yamaha R6 motorcycle engine, hydrogen fuel cell, batteries
and an electric motor to create one multiple-input hybrid powerplant. “Because of its parallel con guration, it could be powered by both the R6 and electric motors, or just electric regeneration, depending on how we chose to run at the time.”
Needless to say, the BAR-1’s success generated huge excitement on campus, and the powers-that-be quickly realised they had a winning concept on their hands. en and there, UJ’s Alternative Energy Vehicle Project was born.
Bring on the Sun
On the solar front, two vehicles are in the works; Ilanga I (Sun in isiZulu), which is almost complete and ready to pass on to the next generation of undergraduates – and the decidedly more sophisticated Ilanga II (which they expect to complete in time for the next SASC race in 2014).
At the heart of Ilanga I is an aluminium space-frame chassis featuring pushrod double wishbone front suspension, with a
swing arm taking care of the rear. Lightweight marine ply ribs and stringers support its outer aerodynamic glass fibre shell. The terrestrial solar cells – they collectively cover an area of 6 m2 – are arranged into ve arrays. Each array incorporates a point tracking system to ensure maximum cell efficiency. Then, just in case the Sun doesn’t shine, lithium batteries act as energy buffers.
Building Ilanga I proved to be a challenging experience. The solar project leader, Warren Hurter, explains: “As undergraduates last year, we had to learn how to build a chassis, fabricate our own circuit boards and work with composite materials from scratch. It didn’t take us long to discover that coming up with a viable CAD design was the easiest part.”
Serious effort went into developing software used to manage race strategy. “It’s all about power management. You start with full batteries and from then on you have to rely on the Sun,” says fellow team member Stephan Schoeman. “To make this happen we had to factor in variables that included weather, sunrise and sunset profiles, maximum gradient we could traverse and how to make up energy through regenerative braking. We also have to be able to calculate these values in real time without contacting the driver too much, as communication systems require lots of power.”
Work has just begun on their secondgeneration solar vehicle, Ilanga II. Once nished, this futuristic looking set of wheels
will be one of the most expensive vehicles to be found on SA roads. Its 3 m2 of spacegrade Gallium Arsenide solar panels (the most efficient produced to date) cost about R3 million alone. Two super-efficient rear hub motors, power converters and controllers are collectively worth about R800 000. And let’s not forget the fabrication of a carbon fibre monocoque chassis with gullwing doors, lithium battery pack, two custom- safety structure and four carbon fibre motorcycle wheels.
The same, but different
Apart from their different powerplants, the hydrogen- and turbine-powered vehicles are identical. They use the same chassis, lithium battery packs and electrical systems to drive their permanent magnet synchronous motors. The idea is
that future students can some day replace components – for example, the battery management system – with their own,
says Smith. “And, if they work better, we’ll incorporate them.”
The hydrogen-powered derivative incorporates an old 5 kW permanent exchange membrane (PEM) fuel cell, sourced from a cellular base station. Hydrogen is a green fuel, but it’s also tricky to work with because of its volatility. Safety is critical: “We can’t afford to have any leaks whatsoever,” Smith says.
The hobby-grade turbine motor measures a mere 51 by 20 cm. But despite its small size, modest 6 kW output and high-revving nature (it idles at 70 000 r/min and goes up to 180 000), it is more than capable of spinning the generator that keeps the batteries charged.
Multi-fuel compatible (it currently burns paraffin, and there are plans to run it on methane), it boasts an operational efficiency of between 50 and 60 per cent, signicantly better than a piston engine’s rather modest 32 per cent. Another plus: it has only three moving parts. “I honestly feel that, if more attention had been put into turbines instead of internal combustion engines, we’d be in a better place right now,” says Smith.
When the teams competing in the 2012 Solar Challenge hit the road in September, UJ hopes to have all three of its designs on the start line. The Ilanga I will take part in the entry level solar class and the other two will compete in the Adventure class. Once complete, the Ilanga II will be entered into the presigious Olympia category for the next event, taking place in 2014.
Follow the progress of Ilanga I and Ilanga II on the University of Johannesburg’s solar car Web site http://www.ujsolar.co.za/
RACING FOR GLORY
e internationally recognised biennial South African Solar Challenge, which takes place this September, is a race not to be taken lightly. Designed to showcase solar technology and alternative energy breakthroughs, it’s a gruelling, two-week aff air. Competitors take on a circuitous 5 000 km route from Johannesburg, down to Cape Town, along the coast up to Richards Bay, and then back to the Gauteng start line.
“The designs entering the event are not toys; they are world-class competitive vehicles,” says Professor Johan Meyer, head of UJ’s Electrical Engineering School. “To give you some idea of what I mean, the Japanese team that beat us in 2010 used scrapped solar panels from the Hubble telescope. The cost of these vehicles can run into six zeros.”
ON THE WEB >Click on Meet Illanga l, a solar car competing in the 2012 South African Solar Challenge to watch a video of the UJ Solar Team talking about the ins and outs of building their solar vehicles