快猫短视频

TO THE engineers and steam buffs gathered in the auditorium, most of the images in Roger Waller鈥檚 video were familiar enough 鈥� the gleaming bulk of a black locomotive standing in Waller鈥檚 workshop, a small loco climbing a precipitous mountain railway, an elegant paddle steamer crossing the blue waters of a Swiss lake. What caused a ripple of surprise, though, was a short sequence near the end. It showed a small green car with a round silver tank zipping along a Swiss road, its twin exhausts puffing out clouds of white vapour.

Waller is a modern steam pioneer. Along with a team at his engineering company DLM in Schaffhausen, northern Switzerland, he has spent the last decade redesigning and modernising steam locomotives to make them far cleaner, and more profitable, than 鈥渙ld steam鈥�. His updated steam engines run on railway routes in Switzerland and Austria, propel a paddle steamer on Lake Geneva and will soon appear on Dutch and Indian railways. Waller reckons that steam still has plenty of potential and, as he showed in the auditorium at the meeting in York, UK, in December 2006, he is even setting steam engines back on the road.

The video showed Waller and his team putting their steam car through its paces on the streets of Schaffhausen. The vehicle does not have a firebox for burning fuel and a boiler like a conventional steam engine. Instead it runs on hot, high-pressure steam stored in an insulated tank, or 鈥渟team accumulator鈥�. When the driver pushes the accelerator, steam is fed into a two-cylinder steam engine which powers the car鈥檚 wheels.

Constructed in 2006, the small green car was just a proof of principle, says Waller. It manages just 10 kilometres or so before it runs out of puff. However, he is now building a second 鈥渢hermomobile鈥� which should have far better performance. With no emissions besides water, this vehicle will be as environmentally friendly as an electric car and offer similar performance, he says, yet cost far less to build and run. 鈥淚t also takes 5 minutes to recharge, which is a huge advantage.鈥�

While he has no plans to take on the mighty manufacturers of Detroit or run the internal combustion engine off the road, Waller is committed to showing that stored steam can be both technically and economically viable. And he鈥檚 not a lone voice 鈥� BMW and Honda are investigating the use of steam as a way to reuse waste heat from car engines, while a Canadian company is developing a steam accumulator system much like Waller鈥檚 device which it claims will cut a car鈥檚 fuel consumption by up to a third. Steam, it seems, is back.

The idea for Waller鈥檚 steam car project started with a holiday. In 2004 he was planning a ski trip to the Alps and began flicking through guide books. Waller was looking for one of the more remote Alpine resorts 鈥� besides good skiing, these inaccessible villages are car-free, offering the added bonus of no traffic noise and pollution. Though he found plenty of books on famous destinations like Zermatt, he found nothing covering Switzerland鈥檚 car-free resorts. So he convinced a friend, journalist Andreas Schwander, to write one.

During his research, Schwander discovered that though conventional cars are banned, these resorts are not completely car free. Residents use small electric vehicles to get about. However, they are extremely unpopular since they are expensive, slow to recharge and have poor battery performance, especially in cold weather. When Schwander mentioned his discovery to Waller, it set the engineer wondering whether steam could do any better.

Steam cars are seriously old technology. Many of the earliest road vehicles ran on the stuff. By the 1920s, though, the convenience of the internal combustion engine had pushed them aside.

Waller realised that if a steam vehicle was to compete with an electric car, it would have to be simple to operate, and cheap to build and run. That meant dispensing with the on-board firebox and boiler. What, he wondered, if the car was propelled by steam supplied from an external boiler and stored on board in a high-pressure tank. This approach was used throughout the 20th century in 鈥渇ireless鈥� locomotives that shifted freight and ore in factories and mines all over the world. Though they were mostly phased out by the 1960s, Waller decided the idea offered an elegant solution, and set about resurrecting the concept to create a fireless steam car.

Hit the highway

By August 2006 he and his team had got hold of a small electric car and begun to modify it. They replaced the batteries with an insulated steam storage tank and fitted a 100-year-old two-cylinder steam engine in place of the electric motor. Filled up with steam from a boiler at the warehouse, 鈥渋t worked straight away鈥�, says Waller. Unfortunately, the driveshaft could not handle the torque generated by the steam engine and it snapped during tests. The team replaced it with a stronger design and hit the road (see diagram).

With a 100-litre tank filled with steam and hot water to a pressure of 10 atmospheres, the vehicle can manage trips of about 40 minutes, averaging around 10.5 kilometres per hour. Waller admits this performance is poor, even by the standards of small electric cars, but he has no doubt the technology could do much better. 鈥淲e don鈥檛 call our first thermomobile a prototype, we call it a demonstrator. It was built in a very short time from existing components.鈥�

Waller has already started building his next vehicle, which he calls the 鈥淗ot₂gO thermal storage car鈥�. This time it is being constructed from scratch, with a storage tank capable of handling steam at pressures of up to 120 atmospheres and at temperatures of around 400 掳C. Under these conditions the steam will be in a superheated state, which will enable the tank to store far more energy. This means the Hot₂gO will have a far better performance than its predecessor, Waller says.

He has already proved that modern steam power can deliver some benefits on the railway. His locomotives are about twice as efficient as 1930s designs, and they can even compete with modern diesel engines: in operation they consume around half as much fuel per passenger. To achieve this performance, Waller builds the steam engines from scratch, swapping heavy, cast iron cylinders with welded units made from lightweight steel. He also replaces old-fashioned brass bearings with modern roller bearings and updates the insulation on boilers and pipe work to modern standards (快猫短视频, 17 July 1999, p 42). He plans to put all these ideas to work in his thermomobile.

But how will steam fare against battery power? Waller has not finished his calculations but estimates that a fireless steam car will be more robust and cost less to maintain than an electric car. Provided construction costs are comparable, he thinks that the steam car will have lower costs over the lifespan of the car. Certainly it should be more popular with drivers, he says, since it can be recharged in minutes rather than hours, and a tankful of steam should remain hot overnight so it can be used in the morning. 鈥淚t will also be maintenance free,鈥� he claims. 鈥淭here will be no need to lubricate its bearings, as they will be fully sealed.鈥�

Of course you are not likely to find a steam source at your local filling station. Waller admits that could be an issue, but argues that steam boilers are already all around us 鈥� in power plants, hospitals, laundries and other small industrial units. He reckons the lack of infrastructure would not be a problem for long. 鈥淪team can be easily produced with any form of energy, such as solar energy or biomass,鈥� he says (see 鈥淩unning on sunshine鈥�). 鈥淯nlike fuel cells, this technology is readily available, relatively cheap and has a big potential for improvements without the need for fundamental research.鈥�

鈥淪team can be produced easily from any form of energy, such as solar power or biomass鈥�

Alpine testing

Schwander鈥檚 research suggests that Swiss resort towns like Zermatt and nearby Saas-Fee could be the first markets for the Hot₂gO. 鈥淢y belief is that [steam] can be economically viable in certain areas, so it shouldn鈥檛 be ignored,鈥� Waller says. Yet while he foresees a limited market for steam cars beyond this, other engineers hope to give the technology much broader appeal.

Engineers at Clean Power Technologies (CPT) in Calgary, Canada, are investigating steam storage as a way to increase the efficiency of conventional vehicle engines. The idea is to capture waste heat from an engine鈥檚 exhaust and store it as steam in an accumulator. It can then be used either to drive the engine鈥檚 crankshaft, or to power small auxiliary engines like those used to cool refrigerated containers or air conditioning. Both BMW and Honda are developing steam systems that reuse wasted heat directly to help drive the crankshaft (快猫短视频, 2 February, p 32), but by storing it in a steam accumulator, CPT鈥檚 system can deliver power for hours even after the engine is switched off.

In March, the company signed a deal with German engine manufacturer Voith Turbo to develop energy-recovery systems for trucks. Tests carried out last year suggest that the technology can offer fuel savings of up to 40 per cent. This ties in with results from a recent study by a team from Loughborough University and the University of Sussex, both in the UK. In April, the researchers reported that converting waste exhaust heat from a vehicle鈥檚 engine into steam and reusing it could cut fuel use by up to 31 per cent. This kind of performance should be achievable at realistic operating pressures in the accumulator, the team suggests.

Waller, who is now a consultant for CPT, knows that developing steam to work alongside current engine technology will be a monumental task. He鈥檒l have to take on manufacturers with his alternative steam design, mindful of the fact that revitalising an old concept is always challenging because there is an image you have to defeat. But if it鈥檚 possible on the railway, he argues, then why not on the highway too?

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