A team led by Dr Ole Martin Løvvik of Oslo University’s Centre for Materials Science and Nanotechnology in Norway has found a way of making cheap thermoelectric materials that could harvest waste heat from a range of scenarios.
However, attempts to bring the technology into the mainstream, in order to harvest waste heat from industrial and everyday scenarios, have been limited by cost and practicality.
Løvvik said the key to the problem is that a good thermoelectric material ought to have high thermal resistance but low electrical resistance. Therefore, it is important to prevent heat dissipation through the material.
The team achieved this by introducing nanoscale barriers into various common semiconducting materials, which reflect waves of vibrating ‘hot’ energetic particles of certain frequencies.
The fabrication method involves cooling down blocks of semiconducting materials to -196°C with liquid nitrogen to make them more brittle and less sticky, then grinding them down into nanoscale particles using a ‘mill.’ These particles are then essentially compressed back together in a controlled fashion, leaving the essential nanoscale barriers.
Calculations suggest it could recover around 15 percent of all energy losses in a variety of scenarios.