A concept paper published in ACS Photonics, describes a photovoltaic cell that works at night.
According Jeremy Munday, one of the paper's authors and a professor in the Department of Electrical and Computer Engineering at UC Davis
a specially designed photovoltaic cell could generate up to 50 watts of power per square meter under ideal conditions at night, about a quarter of what a conventional solar panel can generate in daytime
The described cell is thermoradiative and emits infrared radiation to space, which has a much lower than Earth temperature of 2.73 Kelvin.
"A regular solar cell generates power by absorbing sunlight, which causes a voltage to appear across the device and for current to flow. In these new devices, light is instead emitted and the current and voltage go in the opposite direction, but you still generate power," Munday said. "You have to use different materials, but the physics is the same."
The device would work during the day as well, if you took steps to either block direct sunlight or pointed it away from the sun. Because this new type of solar cell could potentially operate around the clock, it is an intriguing option to balance the power grid over the day-night cycle.
Journal Reference: [Nighttime Photovoltaic Cells: Electrical Power Generation by Optically Coupling with Deep Space, ACS Photonics (DOI: 10.1021/acsphotonics.9b00679)
(Score: 2) by JoeMerchant on Monday February 03 2020, @02:58AM
Clearly not.
First, space itself has ~3K background temperature, at least in our neighborhood.
Second, the atmosphere would conduct a great deal of heat over from the day side.
Third, something like a grape skin thickness beneath our feet (in relative terms) is magma at roughly 975K.
However, even with all those in mind, also bear in mind that the night side of Mercury is -180C (155K) while the day side cooks at 430C (700K), precisely due to passive radiation of heat to space and the tidal lock that keeps it from rotating. For reference, at our distance from the sun, the moon swings from -173C (100K) to 127C (400K) as it passes through night and day on it's 29 day solar cycle.
So, while we've got stuff on the ground "glowing hot" at 260+K, it's not hard at all to imagine extracting energy from that glow before it heads on to the rather large heat-sink of outer space, particularly in the "color bands" (infra red, I believe) where the atmosphere is most transparent to the glowing energy.
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