Hot prospect

Researchers in Germany are developing a thermoelectric generator to convert the heat from car exhaust fumes into electricity. The device will feed energy into the car's electronic systems and could cut fuel consumption and help reduce the vehicle's CO

emissions.

A thermoelectric generator creates voltage when there is a different temperature either side of it. So the greater the temperature difference, the more current the generator can produce.

A team from the

is developing new thermoelectric materials, modules and systems to harness this kind of residual heat.

'The temperature in the exhaust pipe can reach 700ºC or more,' said Harald Böttner, head of the Thermoelectric Systems department. 'The temperature difference between the exhaust and a pipe carrying engine cooling fluid can thus be several hundred degrees,' he added.

The thermoelectric converter will make use of this huge differential. With the flow of heat from the exhaust fumes on one side and the cold side of a coolant pipe on the other, the charge carriers will pass through special semiconductors and produce a current similar to a battery.