I guess we’re calling geothermal energy “reverse solar” now. This is silly marketing.
The system takes advantage of the heat difference between Earth’s surface and the night sky, with the ground radiating much of the heat it captured during the previous day.
It’s not a reverse solar panel. It’s not a solar anything. It requires a difference in heat… So it generates electricity in the same situation that a sterling engine uses to generate motion. Could you put one on a diesel generator to turn the waste heat into more electricity?
Does it have anything in common with
those weird little solid state heat exchangersPeltier elements? Wait, are they actually, literally peltier elements?It’s not a reverse solar panel. It’s not a solar anything. It requires a difference in heat…
The solar part is because the Sun is responsible for the heat differential.
Then you could argue wind energy is just solar energy because wind exists due to heat and thus pressure differential
Or it’s a panel optimized for exploiting infrared light.
Light bulb is a Reverse solar panel
An LED is, anyway
One watt per square meter. Not very useful.
You’re getting downvoted for pointing out that this technology, at optimal efficiency on Earth, generates about 1/100,000 the power of a solar panel. “Not very useful” is an understatement (it’s currently fucking useless). Even worse: the title saying “at night” implies a terrestrial usage and misdirects from this technology’s only potential useful application in the future once and if it becomes much better – namely on deep-space missions.
This research is interesting. I hope it yields something useful. Your comment is still 100% correct for the foreseeable future.
Edit: I was conflating the optimal efficiency of 1 W/m2 and the actual efficiency of 1/100,000 the solar panel. Sorry for introducing that confusion.
That 1/100,000 comparison doesn’t seem right if these panels generate 1W per square meter as the parent poster said. It sounds like you’re saying regular solar panels generate 100kW per square meter but I’m pretty sure that’s orders of magnitude too high. Am I misinterpreting what you said?
Agreed. It’s 1/100 with old panels at 1/300 with modern high performance panels, being up to 300w/m.
Edit: solar radiation is only 1.3kw/m2
Edit: solar radiation is only 1.3kw/m2
Outside earths atmosphere. Only ~650 Watts/m^2 reach the surface of our planet.
Edit: I posted regurgitating some simplified assumption from a text book or something I must have read in the past, the 650 W/m² is wrong.
No that’s not right, it’s about 1000 watts/m2 on the surface. But it is on a totally clear day with the sun directly overhead. So depending on your latitude you get less per m2 because the Earth is round.
Wikipedia says it’s 1361 watts per m2 just outside the atmosphere.
On the power outside the atmosphere I didn’t comment because I was too lazy to look it up, the and I knew the number of the previous commenter was in the ballpark.
Regarding the surface: my apologies, I quoted a number from university that must have been a simplification for a calculation exercise, and I made the mistake of never thinking about it critically. Turns out I was wrong.
even if it only helped eek out 1% returns, on missions depending on an RTEG that could be years added.
worth keeping an eye on.
Clearly you don’t know how much longer sketchy hallways get in the dark. It’s at least a 20 fold increase.
Could be good enough for light in dark places
But… yes
Generally not enough. But maybe with more work they could become better
This has more in common with a thermocouple than a solar panel.
The thing about deep space is confusing. Where is it dark for long periods in deep space?
everywhere
At night…
Everywhere. You have to consider two points: Most light in our nightsky comes from the reflection of sunlight by the Moon. Secondly deep space is not the space between planets or even between the outmost planet and the Kuiper Belt.
It is the place between stars, which is lightyears in diameters and where every star is just a tiny dot in the sky. This is not enough available energy to power our current level of electronics via solar. Which is why i.e. the Voyager probes use RTGs as power source after they left the area of our solar system where solar power is viable.
In interstellar space there is no temperature differential for that solar cell scheme to work from. It only works when there is something that is heated by the sun part of the time, and radiates heat into space the rest of the time. Maybe the far (“dark”) side of the moon counts for that, but for a moon station you probably want batteries or RTG’s or whatever. I’m sure there are uses for this thing but they sound very niche. Radiating heat into space on hot nights on the other hand is quite interesting, as an alternative to air conditioning.
thermoradiative diode sound more like perlier panels than solar panels
Could be interesting if the technology paves the way for more efficient Peltier-like devices
