New Device Harvests Energy In Darkness (nytimes.com) 42
In new research published on Thursday in the journal Joule, Dr. Raman, an electrical engineer at the University of California, Los Angeles, demonstrated a way to harness a dark night sky to power a light bulb. The New York Times reports: His prototype device employs radiative cooling, the phenomenon that makes buildings and parks feel cooler than the surrounding air after sunset. As Dr. Raman's device releases heat, it does so unevenly, the top side cooling more than the bottom. It then converts the difference in heat into electricity. In the paper, Dr. Raman described how the device, when connected to a voltage converter, was able to power a white LED. The prototype built by Dr. Raman resembles a hockey puck set inside a chafing dish. The puck is a polystyrene disk coated in black paint and covered with a wind shield. At its heart is an off-the shelf gadget called a thermoelectric generator, which uses the difference in temperature between opposite sides of the device to generate a current. A similar device powers NASA's Curiosity rover on Mars; its thermoelectric generator derives heat from plutonium radiation. Usually, the temperature difference in these generators is stark, and they are carefully engineered to separate hot and cold. Dr. Raman's device instead uses the atmosphere's ambient temperature as the heat source. The shift from warm to cool is very slight, meaning the device can't produce much power.
His puck-in-a-dish is elevated on aluminum legs, enabling air to flow around it. As the dark puck loses warmth to the night sky, the side facing the stars grows colder than the side facing the air-warmed tabletop. This slight difference in temperature generates a flow of electricity. When paired with a voltage converter, the prototype produced 25 milliwatts of power per square meter. That is about three orders of magnitude lower than what a typical solar panel produces, and well short of even the roughly 4-watt maximum efficiency for such devices. Still, several experts said the prototype was an important contribution to a new and relatively unusual space in the renewable energy sector.
His puck-in-a-dish is elevated on aluminum legs, enabling air to flow around it. As the dark puck loses warmth to the night sky, the side facing the stars grows colder than the side facing the air-warmed tabletop. This slight difference in temperature generates a flow of electricity. When paired with a voltage converter, the prototype produced 25 milliwatts of power per square meter. That is about three orders of magnitude lower than what a typical solar panel produces, and well short of even the roughly 4-watt maximum efficiency for such devices. Still, several experts said the prototype was an important contribution to a new and relatively unusual space in the renewable energy sector.
That is nothing (Score:5, Funny)
I heard about a $30 Device Turns the Cold of Outer Space Into Renewable Energy. Not sure where I heard about it.
Re: (Score:2)
But this is a puck-in-a-dish.
Re: (Score:2)
Not just a dish: a chafing dish.
A chafing dish? (Score:2)
Why, it's a traditional serving piece
used at brunches to keep food warm.
Re: (Score:3)
What is the minimum "dupe-distance" for a Slashdot article?
This one has 8 articles in between.
Re: (Score:2)
I've seen dupes coming one after the other, so the minimum dupe distance was zero.
Re: (Score:2)
Back in the day it wasn't that uncommon to have dupes on the front page, sometimes two at a time.
I wonder if it's a UI issue or something. Do the editors just not read the front page before selecting articles to post?
Re: (Score:2)
It's a hiring issue.
Whoever is running this hole always without fail gives the editor jobs to shit employees with zero work ethic.
I offer as evidence: this site.
Re: (Score:2)
This timer it's different, though--they couldn't see the prior one, because the device doesn't generate enough light . . .
Re: (Score:3)
Maybe Slashdot should change their name to Fuckwit: News for nobody, Stuff that doesn't matter.
Re: (Score:1)
Re: (Score:2)
Phys.org also posts duplicate articles. There's virtually no editing from the "editors" whatsoever, it's usually just a straight dump of a news release. When they do get involved, they're posting clickbait items like the "theory" that humans are ape-pig hybrids. Phys.org's comment moderation is a joke. Spam comments are removed when flagged, but some of the nastiest racist, misogynist, homophobic, profanity-laced posts remain if they come from certain users. My best guess is that because phys.org offer
Re: (Score:2)
Original /. story here: https://science.slashdot.org/s... [slashdot.org]
I heard about a $30 Device Turns the Cold of Outer Space Into Renewable Energy. Not sure where I heard about it.
Re: (Score:2)
That's nothing, I heard about a $30 device that turns Slashdot dupes into renewable energy!
Seriously though, it powers a white LED! What's next, a mechanical monkey with cymbals?
Harvest the crack /. editors are smoking (Score:1)
We could buy enough solar panels to power the lightbulb, then!
Seriously, this is still sitting on the front page 9 stories down.
Pay attention, editors.
Triple refundancy (Score:5, Insightful)
Re: (Score:2)
The article was stupid and pointless enough the first time around.
Maybe because the result was so insignificant, nobody noticed the dupe?
Re: (Score:2)
But now it's a $90 device that can power three LEDs ;-)
I've been talking about this for a year or more (Score:2)
This is the third time in a month this non-story has been posted, and the second time today.
While somebody actually getting around to doing it and announcing it as a breakthrough, I've been talking about this approach for a year or more, practically since the original Stanford work on the infrared-window paint, or perhaps the Colorado glass-bead version, came to my attention. I think I mentioned it here on Slashdot, too.
(I don't claim to have invented it. I seem to recall someone from one of those groups
Re: (Score:2)
While it is a cute approach, we need a substantial improvement in Seebeck effect devices to make it practical for more than token-level power. The glass-bead infrared window teaterial can emit about 90 watts of heat per square meter and produce only a 20C temperature difference, so only a small carnot-cycle fraction of that is available. Then current commercial Seebeck effect devices run at 5 to 8 percent efficiency. So you're talking lighting an LED or powering an IoT device, rather than replacing solar panels.
Pretty much. Though... an IoT-level device that runs on its own 24/7 rain or shine is not an entirely useless thing.
Re: (Score:2)
Yes.
Also: With 24 hour power it wouldn't need a battery (or if its peak power use was of short duration, even a SUPERcapacitor). Ordinary capacitors last for decades, as do electrolytics if kept charged most of the time. So the device could keep running for multiple decades.
Re: (Score:2)
The glass-bead infrared window teaterial can emit about 90 watts of heat per square meter and produce only a 20C temperature difference,
Correction: 10C (about 18F). The Stanford nanostructured pigment is only about half that and I don't have numbers for the water-in-oil void-making paint.
Re: (Score:2)
Not just that, but I'm getting damned tired of seeing paywalled links to the NYT. Stop with the links, editors. I'm not subscribing. Find another link.
Another 'free energy' device (Score:3)
It's just a thermocouple, nothing new.
Any temperature differential will do and there are things that have much greater temperature differentials. You could eg. store energy in a building, in the ground or a plastic box, let's say, filled with some type of fluid like oil or water, acid and lead or salts and then at night, you can release that energy to drive a thing called a turbine (or a thermocouple) of sorts or even a direct conversion from the stored energy into HVAC or HVDC.
A lot of things have temperature differentials. Thermocouples are piss-poor system for generating energy (5% efficiency or so)
An old editors are still posting dupes (Score:3)
Both on the front page at the same time. That's a neat trick.
Interesting, but not useful (Score:2)
Its a quite interesting concept from a pure physics point of view, but not (and never intended to be) a path to practical energy generation.
But yes, its been posted here before
Return on investment (Score:2)
Comment removed (Score:5, Funny)
Ran the numbers and not as bad as I thought (Score:4, Informative)
Re: (Score:1)
What the hell, Slashdot? (Score:4, Informative)
Is it better than the old one? (Score:1)
There's lots of ways to produce power in darkness. Many of them work quite well. Is this device really all that better than what we had before?
This doesn't look like a new device but an improvement on existing heat driven electricity producing devices. Seems like this could be used to improve many kinds of heat driven electricity producing devices. Or to improve on the dissipation of waste heat from any of a number of systems that provide cooling. Such as the heat sink on a natural gas, coal, or nuclea
Heat Batteries (Score:1)
Well.. Maybe they need to mix this with some kind of heat storage.
Cheaper materials for this.
Glass | plexiglass, some air to work as thermal insulator, a metal black painted, a working&storage fluid behind the solar receiver (the black metal) and just pipes to create a better hot side to the generator.
I can see disconnected streetlights with these. Just an alternative to solar panels + chemical batteries.
His TED talk (Score:3)
https://www.ted.com/talks/aasw... [ted.com]
Another Breakthrough Device (Score:2)
I think I can make a device that harvest energy from duplicates! Please call, editors!
I misread (Score:1)
The editors have a Duplear Reactor (for dupes)! (Score:2)
The Slashdot editors have a Duplear Reactor that generates power when they post dupes.
This powers the servers, otherwise the site would go dark.
So, we put up with it, and mock them.
Too bad this is a duplicate, because... (Score:2)
Solar + Battery (Score:2)