Fishing for yellowfin tuna from my ski boat, “Kaspaas”, was good that day, but then the wind picked up and turned the sea into a monster. Returning to the launch site, inside the treacherous inlet of the St Lucia estuary, turned into a nightmare when the huge foam-topped breaker ahead of us completely blocked my view. I missed the channel and had to beach on the soft sand beside the mouth.
The beach was still muddy from recent floods and although we’d loaded the boat successfully, my International 4×4 truck got stuck axle-deep when we tried to move the boat and trailer to higher ground. Fortunately, I had a very capable homemade winch mounted on the front. Powered by the big starter motor of an old 12-cylinder diesel Diamond T truck, working through two reduction gearboxes, it had a ratio of 165:1 that gave it at least 30t of pulling power. Although it got us out, its construction could not withstand such abuse and the tough, steel spool-shaft twisted up like a koeksister.
I had no idea how to fix it and on our way home, I stopped at the farmhouse of my friendly neighbour, who is one man who always had a plan. He simply removed the motor, locked the spool-drum and, by using the low gearbox reduction and a socket wrench, turned it backwards until the axle was perfectly straight again.
At the same time, he invited me into the house to show me a plan that, today, could be used to twist the whole crooked world straight again. It was a strange little tripod-mounted engine, which he had bought during his last visit to the US. “This is the engine that’s needed by the world,” he said, while adjusting a built-in sun reflector, which focused a beam of concentrated sunlight on a specific part of the engine. He spun the flywheel and without a sound, the little engine started. A small gearbox allowed the reflector to keep track of the sun and kept the engine running for the rest of the day.
“What fuel does it use?” I asked. “Any fuel. Right now, it runs on sunlight. But wait…” Going into the house, he returned with a book in his hand. “I bought this for you.” It was a copy of Stirling Cycle Engines, written by Andy Ross. “I wish they would make big Stirling engines, which we could use in our machines, but the motor and oil companies have locked them away, to keep us addicted to their thirsty and noisy engines and to their oil!”
So, that’s what it was – a Stirling engine – a sterling solution that was never put to proper use. That was 25 years ago and my friend was a wonderfully humble, but brilliant man – none other than Irvine Bell, founder of the Richards Bay company that manufactures those huge, yellow Bell articulated, earth-moving hauler trucks that are among the best in the world. From humble beginnings as a diesel mechanic, he created one of the manufacturing giants on the continent. His success never went to his head, which was, instead, always filled with brilliant ideas. Irvine made a study of the Stirling engine and knew what he was talking about. It’s a heat engine that’s not only vastly different from the present internal combustion engine in your car, but has the potential to be much more clean-running, performance-efficient and lighter on fuel than current petrol or diesel engines.
It uses external heat, which could be produced by burning anything from petrol, diesel, paraffin, ethanol, butane gas, coal or wood. It can even use solar energy or heat given off by decaying plants or other organic matter. Small models can run from the heat of your hand. Stirling engines are very quiet, because no combustion and no explosions take place inside the cylinders. Unlike petrol or diesel engines, there are no exhaust valves to expel high-pressure, toxic greenhouse gasses into the atmosphere.
But Stirling engines can be hard to understand. Although there are various types, each one has an elongated, totally sealed cylinder of which one end is kept hot and the other, cold. A piston is moved back and forth from the hot to the cold side by sealed-in gas, which never leaves the engine and is often air, hydrogen or helium.
When the gas is on the hot side, it expands, pushing the piston to the cold side. Here the gas cools down rapidly, contracts and pulls the piston back. It happens very fast and some engines, with two or more cylinders, depending on the power output required, turn a crankshaft at speeds of over 4 000rpm. This makes it sound like wonderful new technology, but it’s not. The Stirling engine was in fact designed by Rev Robert Stirling way back in 1816 to replace the dangerous, exploding steam engines of the Industrial Revolution. Back then it was used for an amazing variety of purposes, but since the advent of the internal combustion engine, it was largely forgotten as an obvious power plant for motor cars.
Stirling engines are presently only used in some very specialised applications like submarines and auxiliary power generators for yachts, where quiet operation is important. They are amazing and will not only function on earth, but even in outer space and on the surface of distant planets where there is no oxygen.
On Mother Earth they can be used for just about every conceivable application where an engine is needed. Just imagine a noiseless, emission-free engine that’s a perfect match for lower-energy biofuel and can be used in presently noisy generators, lawn mowers, motorcycles, boats, cars, trucks, tractors, aircraft or even huge ocean-going liners.
There are plans afoot in Southern California to use Stirling engines to generate electricity in what will be the world’s largest solar power plant. On completion, it will provide clean power to 278 000 homes at only 6US¢/kWh (R6/kWh). Stirling technology is not only much cheaper, but twice as efficient as any other solar system and unlike photovoltaic cells, does not rely on expensive and increasingly limited raw materials. Let’s hope this is the beginning of its rediscovery, because if ever the Stirling engine was needed by the world, it’s now. – Abré J Steyn
Contact Abré J Steyn on 083 235 4833 or e-mail [email protected]. |fw
