Australian nuclear scientists are helping gather extra power from waste heat. 

The Australian Nuclear Science and Technology Organisation (ANSTO)is working on advanced materials that sustainably convert waste heat into useful forms of energy.

Almost all industrial processes create excess heat energy. Currently, technology to convert this waste into usable power (thermoelectrics) is hindered by low conversion efficiency and high cost.

But ANSTO says its research will deliver reliable, high-performance, and cost-effective products that can operate a range of temperatures with higher efficiency than the current commercially available materials.

ANSTO scientists, Dr David Cortie and Dr Kirrily Rule, are leading the development of new thermoelectric devices that rely on multifunctional, nano-engineered topological materials such as bismuth telluride and antimony alloys, which were developed by Prof Wang.

These materials have high electrical conductivity on their surface but act as insulators in the bulk.

“We have worked in this area for quite some time. The basic science came first.  But now we have reached a point, where the knowledge can be applied to materials that are more commercially relevant,” said Dr Cortie.

When comparing thermoelectric studies, the big number to look at is a measure of the effectiveness of different materials, known as zT.

“The zT of a good thermoelectric is presently approximately 1. If we were able to get that to climb to 2 or beyond it would be extremely competitive,” said Dr Cortie.

The group has already achieved a zT of approximately 2.44 at 873 Kelvin with a significant reduction in thermal conductivity, but there is more work to do. 

ANSTO says it will apply the full power of its neutron spectrometers in the Australian Centre for Neutron Scattering to detect and quantify high energy vibrations in atoms, such as phonons, at the quantum scale.

In recent breakthrough research, Prof Wang embedded nanoparticles in the materials to try and impede the flow of phonons, atomic vibrations that carry heat.

“In order to reduce how quickly the heat can move through the material, you need to block the propagation of phonons, reducing their lifetime,” she explained.

The team also anticipates using techniques at the Australian Synchrotron for further investigations.

The research is expected to include processes that convert light into energy in the form of electricity, heat, evaporation, or cooling.