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Engineers harvest clean, continuous energy from air

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Re: Engineers harvest clean, continuous energy from air

#11

Post by joak »

deegles wrote: post #2

The paper says a cubic meter of the material could generate more than a kilowatt (per hour?)... sounds promising if it actually gets commercialized. I assume it would only work well in places where there are significant humidity swings, I didn't read the paper very carefully though. https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202300...

A kilowatt is unit of power. Joule is the unit for energy. A Watt is 1 Joule per second.

A another common unit for energy is kWh (kilowatt.hour)

A kilowatt generator can produce one kWh/h (by definition)

Re: Engineers harvest clean, continuous energy from air

#12

Post by purpleflame1257 »

chrisbrandow wrote: post #8

Despite being a chemist, I don’t fully follow this, though it seems legitimate. But if there’s that much latent energy, I really have to think that there could be some kind of atmospheric, “local ecological” side effect on microorganisms or “something” at scale. It’s not like nature lets massive amounts of energy go completely unused.

Completely? No. But consider how much of a given square meter of sunlight on the ocean is photosynthesized by bacteria and algae, and how much becomes waste heat immediately.

Re: Engineers harvest clean, continuous energy from air

#13

Post by 0x0203 »

oidar wrote: post #3

News releases like this are always optimistic, but there always some hidden cost they don't tell us about.

I didn't read the paper, but judging just from the article, it looks like it requires forcing the humid air through the membrane. I suspect that the energy required to do so is more than it harvests.

Re: Engineers harvest clean, continuous energy from air

#14

Post by amluto »

chrisbrandow wrote: post #8

Despite being a chemist, I don’t fully follow this, though it seems legitimate. But if there’s that much latent energy, I really have to think that there could be some kind of atmospheric, “local ecological” side effect on microorganisms or “something” at scale. It’s not like nature lets massive amounts of energy go completely unused.

The article is quite vague. I assume they’re saying that a humidity difference drives a net flow of water vapor through their machine. So you seal one side and stick something hygroscopic in it as a big humidity sponge and expose the other side to the atmosphere. Then, about twice a day, you get a current if your climate has large diurnal humidity changes.

Re: Engineers harvest clean, continuous energy from air

#15

Post by vajrabum »

Here's the paper behind the story. There is some interesting detail there. From their result it seems that this sort of mechanism can be constructed with a wide range of materials both organic and inorganic. So there a lot of possibilities for how to apply the idea. https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202300...

Re: Engineers harvest clean, continuous energy from air

#16

Post by jrockway »

wlesieutre wrote: post #10
naich wrote: post #6

Earlier quoted context omitted.

Nope.

Watts are a rate of one joule per second. If you want to talk about a quantity of energy rather than a rate of energy production/consumption, the units would be either kilowatt hours or joules (1 kWh = 3,600,000 joules).

Yup, kilowatt hours are a cursed unit that simply reduces to joules (a nice and easy to remember 3.6 million of them).

Re: Engineers harvest clean, continuous energy from air

#17

Post by soperj »

chrisbrandow wrote: post #8

Despite being a chemist, I don’t fully follow this, though it seems legitimate. But if there’s that much latent energy, I really have to think that there could be some kind of atmospheric, “local ecological” side effect on microorganisms or “something” at scale. It’s not like nature lets massive amounts of energy go completely unused.

I don't really see anything harvesting the wind aside from us?

Re: Engineers harvest clean, continuous energy from air

#18

Post by raphaelj »

Something similar happened when I put a dehumidifier in my bedroom.

Basically, I noticed that the room was heating significantly when I turned it on. Way faster than what you should expect from its power usage (about 250W avg.).

Correct me if I'm wrong, but by converting air moisture to liquid water using a compressor, the dehumidifier is releasing the latent energy of water vapor (0.627Wh/L) in addition to its own energy usage.

I measured that my dehumidifier required +/- 1kW/h to get 1L of liquid water from the room. This it's overall heating efficiency is about 1.6x, which is way better than any electric heating system that is not an heat-pump.

Re: Engineers harvest clean, continuous energy from air

#19

Post by thaumasiotes »

soperj wrote: post #17
chrisbrandow wrote: post #8

Despite being a chemist, I don’t fully follow this, though it seems legitimate. But if there’s that much latent energy, I really have to think that there could be some kind of atmospheric, “local ecological” side effect on microorganisms or “something” at scale. It’s not like nature lets massive amounts of energy go completely unused.

I don't really see anything harvesting the wind aside from us?

Plants do it all the time; the basic plant strategies for colonizing new territory are floating on the wind, floating on the water, and fruit.

Re: Engineers harvest clean, continuous energy from air

#20

Post by deegles »

amelius wrote: post #4
deegles wrote: post #2

The paper says a cubic meter of the material could generate more than a kilowatt (per hour?)... sounds promising if it actually gets commercialized. I assume it would only work well in places where there are significant humidity swings, I didn't read the paper very carefully though. https://onlinelibrary.wiley.com/doi/epdf/10.1002/adma.202300...

> more than a kilowatt (per hour?) Not sure what you mean, Watt already has a unit of time in it.

The paper just says "an estimated energy density of >1 kW/m^2"
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