Waste not, want not

Materials that efficiently convert waste heat to electricity could soon
be used to save energy in cars and around the home thanks to researchers at BASF in Germany.

Materials that efficiently convert waste heat to electricity could soon be used to save energy in cars and around the home.

The special materials, under development by researchers at BASF in Germany, exploit the thermoelectric phenomenon in which the application of heat induces an electric current.

The effect was first noticed around 180 years ago by German physicist Thomas Seebeck, who discovered that a voltage was developed in a loop containing two dissimilar metals, provided the two junctions were maintained at different temperatures. But while devices that exploit this phenomenon have been around for some time, high cost and low efficiency has limited their application.

Dr Benedict Raether, who is leading the research at BASF’s Future Business division, explained that while existing thermoelectric modules have an efficiency of around 8-10%, his team has succeeded in dramatically improving the performance and efficiency of thermoelectric materials. The material under development, a semiconducting metal alloy, could open up a range of new applications for the thermoelectric effect, he said.

One of the most promising of these applications is in the recovery of waste heat from vehicles. ‘Sixty per cent of the energy content of fuel is currently released as heat, while only around 30 per cent is used for propulsion or generating electricity in the alternator. The aim is to recover a certain amount of this waste to reduce emissions and improve the efficiency of the system,’ claimed Raether.

He said that his thermoelectric material could, for instance, be used to make a device that recovers heat from the exhaust or radiator of a car and use it to generate electricity to power the air conditioning system.

Raether said that BASF is currently discussing using the technology with a number of car manufacturers, and, hinting at another application area, with companies involved in the ‘household industry.’ BASF expects to have completed the development of the material by the beginning of next year, he said.

The next step, said Raether, is to set up an industrial process capable of producing the material in bulk, and then to work with module manufacturers on the development of thermoelectric devices.

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