A team of researchers at the University of Minnesota has discovered a new alloy that can transform heat into electricity. The approach is new and uses a coil to transform the magnetic field generated by the alloy.
“This research is very promising because it presents an entirely new method for energy conversion that’s never been done before,” said University of Minnesota aerospace engineering and mechanics professor Richard James, who led the research team.”It’s also the ultimate ‘green’ way to create electricity because it uses waste heat to create electricity with no carbon dioxide.”
The new multiferroic alloy has the chemical formula Ni45Co5Mn4Sn10, and has been composed by combining the elements at an atomic level. This material is able to undergo a highly reversible phase transformation to achieve multiferroism. During the phenomenon, in which a solid turns into another solid, the alloy changes its magnetic properties with the changing of temperature.
A small-scale demonstration at the University of Minnesota proved that the material acted as non-magnetic and then when they raised the temperature by a small amount, the same metal turned into a powerful magnet that absorbed the heat and, of course, produced electricity in the coil surrounding it.
The efficiency had been low at first due to a process called hysteresis (where the thresholds of turning into a magnet and back into a simple metal were at different temperatures). The team has however managed to reduce the hysteresis during the phase transformation.
Although still in its infancy, this technology could add up to the multitude of other thermoelectric materials and processes discovered so far and could ultimately capture most of the world’s wasted heat including that coming from cars and power plants, to enhance their efficiencies and bring down the energy costs.
Observe the powerful magnetic field generated by heating the alloy and how it attracts the small piece of metal, in the video below: