Converting infrared heat to electricity could lead to solar power at night

[richfool]

New device converting infrared heat to electricity could lead to solar power at night:

Scientists have successfully tested a device that is capable of converting infrared heat into electrical power.

The device, described last week in the journal ACS Photonics, is based on technology similar to that used in night-vision goggles and may lead to new ways of harnessing the Sun’s energy in the dark of night.

While solar energy warms the Earth during daylight hours, it is lost into the coldness of space when the sun goes down.

In the new study, scientists, including those from the University of New South Wales in Australia, have tested a device that can convert infrared heat into electrical power that uses a power-generation tool called a ‘thermo-radiative diode’, which is similar to the technology in night-vision goggles.

https://uk.finance.yahoo.com/news/devic ... 02172.html

Interesting .

[UncleEbenezer]

Alternatively viewed as a storage technology. The Earth gets hot in the day and radiates some of it back out at night. Not perhaps a primary candidate here in Blighty, though.

[servodude]

Alternatively viewed as a storage technology. The Earth gets hot in the day and radiates some of it back out at night. Not perhaps a primary candidate here in Blighty, though.

True!
Can't go anywhere these parts without hearing
"Strewth Davo's building a peltier junction in his yard!"

[GoSeigen]

Is this an April Fools joke?

GS

[XFool]

From the linked article:

“In the late 18th and early 19th century it was discovered that the efficiency of steam engines depended on the temperature difference across the engine, and the field of thermodynamics was born,” explains Nicholas Ekins-Daukes, a co-author of the study.

“The same principles apply to solar power -- the sun provides the hot source and a relatively cool solar panel on the Earth’s surface provides a cold absorber. This allows electricity to be produced,” he added.

Indeed. But isn't this a rather fundamental problem? Unless the device itself is at a much lower temperature than the 'warmth' of the earth and it's surroundings there won't be a big enough temperature difference to allow extraction of much energy.

C.F. The James Webb space telescope: https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?s=09

Or do they have plans to put these devices in outer space?

[Shirley]

Isnt this very exciting? I think we are going to look back 20 years from now and we'll realise how much has changed.

[XFool]

From the linked article:

“In the late 18th and early 19th century it was discovered that the efficiency of steam engines depended on the temperature difference across the engine, and the field of thermodynamics was born,” explains Nicholas Ekins-Daukes, a co-author of the study.

“The same principles apply to solar power -- the sun provides the hot source and a relatively cool solar panel on the Earth’s surface provides a cold absorber. This allows electricity to be produced,” he added.

Indeed. But isn't this a rather fundamental problem? Unless the device itself is at a much lower temperature than the 'warmth' of the earth and it's surroundings there won't be a big enough temperature difference to allow extraction of much energy.

C.F. The James Webb space telescope: https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?s=09

Or do they have plans to put these devices in outer space?

Revisiting this thread - following the recent post - I was reminded that I had no answer to my original puzzlement of how this was supposed to work, there being no real explanation in the original linked article. A search found this paper online.

https://pubs.acs.org/doi/10.1021/acsphotonics.2c00223#

It started to make sense now. The clue was in the name: ‘thermo-radiative diode’

So the idea is like a solar cell but working in reverse. The diode itself would heat up during the day and radiate heat away to the cold of space at night (if no clouds!) generating electric power in the process.

[Rover110]

Radiated power is proportional to the fourth power of temperature. So something starting out even near 100C is not going to radiate much power; perhaps 1 Watt per square metre.
So I reckon you'd need a huge area to be useful. (Unless you're going for battery-storage and only use the power for a few minutes each night. In which case why not stick with daylight-solar?)

Although it is interesting in the Physics sense, and does away with the need for a "cold end" the way Peltier-effect or Carnot-cycle devices do, I'm currently unconvinced for power-generation applications.

- Rover

[GoSeigen]

Radiated power is proportional to the fourth power of temperature. So something starting out even near 100C is not going to radiate much power; perhaps 1 Watt per square metre.
So I reckon you'd need a huge area to be useful. (Unless you're going for battery-storage and only use the power for a few minutes each night. In which case why not stick with daylight-solar?)

Although it is interesting in the Physics sense, and does away with the need for a "cold end" the way Peltier-effect or Carnot-cycle devices do, I'm currently unconvinced for power-generation applications.

- Rover

Thanks for fleshing out my post!

GS

[XFool]

Although it is interesting in the Physics sense, and does away with the need for a "cold end" the way Peltier-effect or Carnot-cycle devices do, I'm currently unconvinced for power-generation applications.

But it surely doesn't do away with a "cold end" - the source of my original puzzlement? The "cold end" is the cold night sky, which it radiates away to after warming up during the day.

From the originally quoted article:

"While the amount of energy produced through this new test is small – roughly equivalent to 0.001 per cent of a solar cell – they say the proof of concept is significant."

[TUK020]

I remember reading of some interesting research work being done in something similar, which could represent the opportunity to save significant power.

From long ago memory, radiated energy is proportional to the fourth power of the temperature difference of the hot/cold ends.

When you get a clear night, infrared radiates into space, and the temperature drops sharply.

However, when you get any cloud/moisture in the atmosphere, this acts as a thermal blanket, absorbing any radiation and re-radiating it back.

The research was into the impact of the size/shape of the body radiating on the wavelength radiated. The proposition was that you could make paint with microscopic balls in emulsion. Strict control of the diameter of these balls meant that these would radiate at a specific wavelength, which you could then select to pick a notch pass where the cloud is 'transparent'.
The potential application was a very low running cost substitute for air conditioning in climates which are hot and humid (as in most of the tropics). If done at a very large scale, this would result in global cooling.
Done on this level it would have an interesting side effect of making our planet much more visible to intelligent species out there and looking