Last year, we reported on a new technology that uses the effects of radiative sky cooling to generate electrical power at night.
Now, a group of scientists claims to have harnessed this effect to create an 'anti-solar power' cell that can generate 120 times more power than any similar device.
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The potential of radiative sky cooling
Instead of absorbing light from the Sun and transforming it into electricity like your typical solar panel, the technology developed by researchers at Stanford University works in reverse.
Even though there's no incoming heat for solar panels to capture at night, there is still outgoing heat that can be used for energy. By pointing a warm solar panel at the cooling sky at night, this outgoing heat starts to radiate outwards as invisible infrared light.
This is radiative cooling could be used as a cheap nighttime lighting source in cities if we were to tap into its potential.
Using a thermodynamic model of a thermoelectric power generator, Stanford University researchers have worked out a rooftop proof-of-concept that, in theory, can generate 2.2 watts per square meter (10.7 sq ft) without the need for an external energy source.
Working towards low-cost sustainable lighting
"We are working to develop high-performance, sustainable lighting generation that can provide everyone - including those in developing and rural areas - access to reliable and sustainable low-cost lighting energy sources," electrical engineer Lingling Fan from Stanford University said in a press release.
"A modular energy source could also power off-grid sensors used in a variety of applications and be used to convert waste heat from automobiles into usable power."
The researchers claim that their specific design can produce 120 times more energy than similar models and is comparable to the performance of a Carnot heat engine — a theoretical thermodynamic limit for the "perfect" engine.
"This result is significantly higher than the previously reported results and points to the potential applicability of harvesting electrical power at night," the authors wrote in their study.
Of course, this is far from being a finished article, and the current model is yet to come close to being ready for commercial application. Still, considering the benefits it could bring to the domain of renewable energy, this technology is most definitely worth exploring.