One hundred and ninety-seven years ago, the German physicist Thomas Seebeck discovered that by linking up two drivers carried to different temperatures, one very low-current is produced. He extended so an experience of Volta which, in 1794, irritated a frog with caused current by plunging a metallic driver into the bouilante water. It is besides with this phenomenon that they measure temperatures in thermocouple. Since, thermoelectricity did not cease making progress. Last result in date, a nippo-American team perfected a promising material for the conversion into electricity of the motorised heat of exhausts.

Idea is not new, far off. And generators thermoélectriques are commercialised, notably of equipment which draws their heat of a radioactive source. Apparatus mainly in military usage. Japanese Citizen also fabricated watches fed by the difference of temperature between skin and environment. But researches come especially towards the recovery of the heat dispelled by exhausts of engines. Because the potential market is colossal: while the engines of cars show an output from 25 % to 30 %, the recovery of the heat of exhausts by effect thermoélectrique would allow for example to recharge the batteries of hybrid vehicles petrol-electricity.

It is in this context that intervene jobs of a team driven by Jeffrey Snyder, of California institute of technology (Caltech), which were published by the magazine Science of July 25th. Snyder and his seven American and Japanese colleagues doped of the tellure of lead with the thallium. In difference of equal temperature, their material shows thermoélectriques performances twice as high as the tandem tellure of considered lead / sodium as the most efficient. Better, this new material shows its best results in a range of temperature (around 500°C) compatible with that of motorised exhausts. But the researchers are still unable to determine the quantity of fabricated electricity. The road will be long before seeing commercial applications.

To know more about thermoélectrique effect: GENERATION THERMOÉLECTRIQUE

Picture: © Denis Delbecq - on 2008