CibbuanoNew thermoelectric materials offer boost in efficiency for capturing waste heat
October 28th 2008 00:51
One of the side products of any energy generation is waste heat - that is, heat produced by a process, but unable to be directed in any useful way.
There is a lot of work on recapturing this heat, from using it to heat pools, or heating water to power steam generators.
One direct way to turn heat into electricity is with thermoelectric materials, shown in the image above. With a heat difference across two sides of the material, an electric current flows. The greater the difference, the more current flows.
In general, though, these devices are quite inefficient at producing electricity this way - instead, the image shows how the device is more likely to be used... we pass current through it to control the heat difference.
Researchers from Northwestern University have found that adding antimony to these thermoelectric materials can dramatically increase the efficiency of the process, though.
"Mercouri Kanatzidis, a professor of chemistry at Northwestern University in Illinois who led the research, said that his new material could be used to produce a new generation of devices that were up to 14% efficient. He said a longer-term efficiency goal for his work was around 20%."
Since we're talking about reclaiming waste heat, any amount that we can get back is better than nothing. Hell, you could even reclaim some of the heat given off by your sweaty body when exercising, recharging your iPod's batteries.
Well, maybe that's dreaming. And we're still a long way from efficiently harvesting energy from heat, but, hopefully, we'll get there.
Imagine! A world without waste heat! It seems like a simple, boring thing to work towards, but, actually, we could dramatically improve the efficiency of all our industries. Then, no more heat wasted...
ScienceDirect has the actual paper from the authors - if you have access to this journal, download it and take a look. Otherwise, here's part of the abstract:
"A series of Ag-doped La0.6Pb0.4MnO3 thin films were grown on vicinal cut substrates by pulsed laser deposition (PLD). Laser-induced thermoelectric voltages (LITV) had been observed in these films, and these LITV signals had been demonstrated to originate from the anisotropic Seebeck effect. By doping Ag to an optimum value, it was found that the peak values (UP) of the LITV signals were maximized, and the full-width at half-maximum (τ
of the response curves of LITV were minimized at the same time. "You said it!
*this image is from NovaTec
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