Nanotechnology brings space generators to earth

THERMOELECTRIC GENERATORS (TEGs) used on spacecraft can be adapted using nanotechnology to increase the efficiency of automobiles.

Researchers at Heriot-Watt University, UK have been awarded more than £780,000 (US$1.1m) by the Engineering and Physical Sciences Research Council (EPSRC) to manipulate the nanostructure of alloys to increase the energy conversion efficiency of potentially commercial generators.

TEGs have proven to be very reliable as the energy is produced using the Seebeck effect – the diffusion of electrons from the hot to the cold side of a material – which does not require any moving parts to operate. TEGs are usually made from rare, toxic metals. However, the team hopes to create similar generators using combinations of abundant metals such as nickel, titanium and tin.

TEGs generate electricity when there is a temperature difference between two electrical conductors. The thermal conductivity of the electrical conductors can be reduced by introducing a spontaneous nanostructure. Reducing the thermal conductivity enables larger temperature differences between each side of the reactor, thereby improving electricity generation.

Jan-Willem Bos, professor of chemical sciences at Heriot-Watt said, “So far, thermoelectric generators have been restricted to niche applications, such as powering the Voyager space probes.”

The team hopes TEGs can make an impact in automobile technology, where they could be embedded in the exhaust system to generate electricity. This could lead to reducing the size of the alternator and increasing fuel efficiency.

Bos said in principle, TEGs can be used in a number of industries such as power plants, manufacturing, and the petrochemical industries, where waste heat of 200–600°C is produced that matches the best performance of the materials under investigation.