Tau.Neutrino said:
Silicon chip breaks “blackbody limit” to produce more electricity from heat than thought possible
Energy conservation is a no-brainer and more important than ever, but it’s not just about environmental implications. If we’re to successfully create smaller, better, more efficient technology, then the thermal energy that our gadgets waste needs to be put to much better use. This new device, which works at the nanoscale where the theoretical “blackbody limit” falls apart, could be the answer.
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> The blackbody limit is a theory which describes the maximum amount of energy that can be produced from thermal radiation (heat), but when objects get very, very close, the law breaks down and thermal transfer from one object to another increases exponentially. So, in short, the closer the objects, the better the energy transfer, but the mechanical difficulty of keeping two objects as close as possible without letting them actually touch has been a significant challenge.
I didn’t see that one coming. Is this related in any way to the Casimir effect? There again the challenge is keeping two objects as close as possible without letting them actually touch.
> We report a maximum heat transport enhancement of approximately 28.5 over the blackbody limit.
Shoot, that’s a huge factor.
> The devices use micropillars, separating the high-temperature emitter and low-temperature receiver, manufactured within micrometre-deep pits. These micropillars, which are about 4.5 to 45 times longer than the nanosize vacuum spacing at which radiation transfer takes place, minimize parasitic heat conduction without sacrificing the structural integrity of the device.
Nice!
The ArXiv preprint is at https://arxiv.org/ftp/arxiv/papers/1811/1811.06485.pdf
> In the near field (i.e., subwavelength vacuum gap spacing), tunneling of evanescent modes allows for radiative heat transfer to exceed Planck’s far-field blackbody limit by orders of magnitude.