Generating Light from Darkness. Raman, A. P., Li, W., & Fan, S.
Generating Light from Darkness [link]Paper  doi  abstract   bibtex   
[Highlights] [::] A thermoelectric generator is built whose cold side radiates heat to the sky [::] Night-time power generation of 25 mW/m2 is demonstrated, sufficient for a LED [::] Pathways to performance $>$ 0.5 W/m2 using existing commodity components exist [::] This approach is immediately practical for lighting and off-grid sensors [Context & Scale] Reliable energy access remains a challenge, particularly in off-grid regions throughout the world. While solar cells have enabled distributed power generation during the day, no comparable alternative exists at night. In this report, we demonstrate a low-cost, modular mechanism of renewably generating meaningful amounts of electricity at night by harnessing the cold darkness of space. We use a passive cooling mechanism known as radiative sky cooling to maintain the cold side of a thermoelectric generator several degrees below ambient. The surrounding air heats the warm side of the thermoelectric generator, with the ensuing temperature difference converted into usable electricity. We highlight pathways to improving performance from a demonstrated 25 mW/m2 to 0.5 W/m2. Finally, we demonstrate that even with the low-cost implementation demonstration here, enough power is produced to light a LED: generating light from darkness. [Summary] A large fraction of the world’s population still lacks access to electricity, particularly at night when photovoltaic systems no longer operate. The ability to generate electricity at night could be a fundamentally enabling capability for a wide range of applications, including lighting and low-power sensors. Here, we demonstrate a low-cost strategy to harness the cold of space through radiative cooling to generate electricity with an off-the-shelf thermoelectric generator. Unlike traditional thermoelectric generators, our device couples the cold side of the thermoelectric module to a sky-facing surface that radiates heat to the cold of space and has its warm side heated by the surrounding air, enabling electricity generation at night. We experimentally demonstrate 25 mW/m2 of power generation and validate a model that accurately captures the device’s performance. Further, we show that the device can directly power a light emitting diode, thereby generating light from the darkness of space itself.
@article{ramanGeneratingLightDarkness2019,
  title = {Generating Light from Darkness},
  author = {Raman, Aaswath P. and Li, Wei and Fan, Shanhui},
  date = {2019-09-12},
  journaltitle = {Joule},
  volume = {0},
  issn = {2542-4785, 2542-4351},
  doi = {10.1016/j.joule.2019.08.009},
  url = {https://doi.org/10.1016/j.joule.2019.08.009},
  urldate = {2019-09-13},
  abstract = {[Highlights]
[::] A thermoelectric generator is built whose cold side radiates heat to the sky
[::] Night-time power generation of 25 mW/m2 is demonstrated, sufficient for a LED
[::] Pathways to performance {$>$} 0.5 W/m2 using existing commodity components exist
[::] This approach is immediately practical for lighting and off-grid sensors

[Context \& Scale]
Reliable energy access remains a challenge, particularly in off-grid regions throughout the world. While solar cells have enabled distributed power generation during the day, no comparable alternative exists at night. In this report, we demonstrate a low-cost, modular mechanism of renewably generating meaningful amounts of electricity at night by harnessing the cold darkness of space. We use a passive cooling mechanism known as radiative sky cooling to maintain the cold side of a thermoelectric generator several degrees below ambient. The surrounding air heats the warm side of the thermoelectric generator, with the ensuing temperature difference converted into usable electricity. We highlight pathways to improving performance from a demonstrated 25 mW/m2 to 0.5 W/m2. Finally, we demonstrate that even with the low-cost implementation demonstration here, enough power is produced to light a LED: generating light from darkness.

[Summary]
A large fraction of the world’s population still lacks access to electricity, particularly at night when photovoltaic systems no longer operate. The ability to generate electricity at night could be a fundamentally enabling capability for a wide range of applications, including lighting and low-power sensors. Here, we demonstrate a low-cost strategy to harness the cold of space through radiative cooling to generate electricity with an off-the-shelf thermoelectric generator. Unlike traditional thermoelectric generators, our device couples the cold side of the thermoelectric module to a sky-facing surface that radiates heat to the cold of space and has its warm side heated by the surrounding air, enabling electricity generation at night. We experimentally demonstrate 25 mW/m2 of power generation and validate a model that accurately captures the device’s performance. Further, we show that the device can directly power a light emitting diode, thereby generating light from the darkness of space itself.},
  keywords = {~INRMM-MiD:z-E776WSR6,energy,precursor-research,renewable-energy,technology},
  langid = {english},
  number = {0}
}
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