Soothing air for your derriere
Sydney Morning Herald
Friday October 2, 2009
The science of keeping your backside comfortable. They're a funny lot, those French. They invented snails as a meal. Enough said.But it's the curiosity of a French physicist eloquently named Jean Charles Athanase Peltier that has brought us one of motoring's most curious features €” car seats that can either cool or heat at the flick of a switch.The story goes that almost 200 years ago, Peltier was sticking bits of different metals together and hooking them up to an electric current to see what would happen.He noticed that where the metals touched each other, if he ran the current in one direction the join would heat up but if he reversed the current the join would cool down.Leap forward a couple of centuries to Phil Peltier sitting in his Lexus luxury car. At the flick of a small dial, his seat heats up magically. Turn it the other way and it cools down.Historically, what Phil has done is invoke the Peltier effect, so named in commemoration of the achievement of his long-lost relative.In circles that attract the scientific boffins, it's known as the thermoelectric effect.In its most basic form, a heated seat unit consists of a fan hooked up to a honeycomb of thermoelectric metal.The fan blows air through the metal, which is either heating up or cooling down according to the direction of the electric current passing through. The air then passes through the seat's foam cushion and through the fabric or perforated leather surface.It has other applications, too. Some cars, such as the Chrysler Sebring, have a cupholder that can either keep a cup of coffee hot or, at the flick of a switch, keep a can of drink cool. It has its limitations, though, as it will only heat to about 60 degrees and cool to about 20 degrees below ambient temperature (so if it is 30 degrees in the car, it will only cool to 10 degrees).But seats that heat and cool themselves may soon be old hat as a raft of new technology is rolled out.The latest-generation Prius petrol-electric hybrid hatchback has a solar panel that can be fitted as an option to power fans to keep the car's interior cool in the heat of the day.Volvo has a similar system run by batteries that, at the push of the key fob's unlock button, pushes all the stagnant hot air out of the cabin and replaces it with fresh, cooler air.Read more at drive.com.au/motoring-101
© 2009 Sydney Morning Herald
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