Thermoelectric materials based on 'nano cages' capture waste heat

October 09 2008 / by Garry Golden
Category: Environment   Year: 2018   Rating: 2

Thermoelectric materials can convert waste heat into electricity, or use electricity for cooling systems. Now European researchers have uncovered new insights into molecular ‘nano cages’ that might make this process of solid state energy conversion efficient.

Researchers at the University of Århus, Risø-DTU and the University of Copenhagen Niels Bohr Institute stand jointly behind new data, published in Nature Materials, that describes thermoelectric materials that could lead to breakthrough practical applications in improving engines, industrial machines, and also advance eco-friendly cooling systems for refrigeration and electronics.

Capturing waste heat – the ultimate in conservation
When we imagine ways to conserve energy and reduce waste, the real measurable gains for the planet have little to do with changing light bulbs. The area which holds the greatest potential is waste heat recovery from industrial processes, combustion engines and cooling systems. These are the most energy intensive and wasteful forms of energy conversion in the modern world.

Thermoelectric materials can be assembled into mechanical structures, which can transform the thermal difference to electrical energy or vice versa – electrical current to cooling.

Nano-cages or molecule trapping clathrate cages
The European researchers studied promising thermoelectric materials in the group of clathrates, which create crystals full of ‘nano-cages’.

“By placing a heavy atom in each nano-cage, we can reduce the crystals’ ability to conduct heat. Until now we thought that it was the heavy atoms random movements in the cages that were the cause of the poor thermal conductivity, but this has been shown to not be true”, explains Asger B. Abrahamsen, senior scientist at Risø-DTU.

“Our data shows that, it is rather the atoms’ shared pattern of movement that determines the properties of these thermoelectric materials. A discovery that will be significant for the design of new materials that utilize energy even better”, explains Kim Lefmann, associate professor at the Nano-Science Center, the Niels Bohr Institute at the University of Copenhagen.

News about thermoelectric materials is admittedly geeky when compared to stories about advances in solar and wind. But these systems are extremely important to transforming the dominant wasteful energy systems that already exist in our world. And this research adds to the growing list of recent fundamental breakthroughs that could help improve the world’s energy systems.

Related reserch and studies:
-Clemson researchers calculated that capturing wasted heat could save billions. “Even at the current efficiencies of thermoelectric devices, 7 to 8 percent, more than 1.5 billion gallons of diesel could be saved each year in the U.S. if thermoelectric generators were used on the exhaust of heavy trucks. That translates into billions of dollars saved,” [via ScienceDaily.com and MIT Technology Review
-UC Berkely scientist trapped nanoparticles for the same effect.
-MIT Technology Review research highlights
-Silicon nanowires in Chemical & Engineering News

Via: EurekaAlert
Niels Bohr Institute Original Press Release and Image Credit

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