
Experimental device generates electricity from the coldness of the universe - lelf
https://phys.org/news/2019-05-experimental-device-electricity-coldness-universe.html
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inflatableDodo
I've thought of trying this before with a toy sterling engine and a tinfoiled
satellite dish. You can make ice that way when the air temp is up to 9 or 10
celcius if you put a shot glass of water in polystyrene foam with an opening
at the focal point of the dish.

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TheSpiceIsLife
Wait what?

Wouldn’t the infrared reflectivity of the parabola concentrate heat energy _in
to_ the focal point?

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inflatableDodo
You point it at an empty patch of sky.

edit - have a go at pointing an infrared thermometer at an empty patch of sky
on a clear night.

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TheSpiceIsLife
Oh, right, I understand now, thanks.

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inflatableDodo
I love radiative cooling. When you first realise what the hell is going on, it
is one of those 'aha' moments of real deeper appreciation of a subject.

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duckymcduckface
My favorite demo is an electric stoves, turn it on and stare at it from a
point along the plane that it's on and you start to marvel at how much heat
can be transferred by radiation.

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TheSpiceIsLife
Isn’t that convection? The air coming in to contact with the hot surface
rapidly heats and rises and cooler air rushed in to replace it.

I thought that’s what we saw as per your instructions? I thought air (mostly
nitrogen and oxygen) is mostly transparent to infrared radiation?

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newsbinator
Maybe one reason we can't detect advanced civilizations is because they're
capturing and recycling all their waste heat & waste EM.

We could start looking for cold spots that should be warm.

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raverbashing
Could be. I never bought the whole Dyson spheres idea.

A truly advanced civilization wouldn't need that much energy (they would be
very efficient), and certainly wouldn't need to "kidnap" a start for that.

A single digit percent of the Earth would need to be covered with solar panels
with today's technology for our energetic consumption, I don't see why
advanced civilizations would need let's say 10% of the energy of a star (let
alone need to capture it)

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ajuc
> they would be very efficient

[https://en.wikipedia.org/wiki/Jevons_paradox](https://en.wikipedia.org/wiki/Jevons_paradox)

> In economics, the Jevons paradox (/ˈdʒɛvənz/; sometimes Jevons effect)
> occurs when technological progress or government policy increases the
> efficiency with which a resource is used (reducing the amount necessary for
> any one use), but the rate of consumption of that resource rises due to
> increasing demand.[1]

> In 1865, the English economist William Stanley Jevons observed that
> technological improvements that increased the efficiency of coal-use led to
> the increased consumption of coal in a wide range of industries. He argued
> that, contrary to common intuition, technological progress could not be
> relied upon to reduce fuel consumption.[4][5]

With enough energy crazy things are possible. Terraforming planets, human-
lifespan interstellar travel, swarms of space habitats allowing everybody to
have their own ecosystem changing to their will. Assuming people won't do it
because they don't do it now (when energy is limited) is unwise.

Don't you think some rich people would like to have their own space habitat
where they can change gravity, day-night cycle, and the whole ecosystem at
will? It's possible with current technology, just very expansive. It creates
new real estate from scratch. With enough energy everybody could have one.

I don't see any point at which people decide "this is enough". Always there
will be some people that want more.

BTW I agree it won't be a Dyson sphere, it will probably be a Dyson swarm.
Much easier to start, cheaper, and has all the benefits of a sphere.

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raverbashing
That's a good comeback

The counterproblem is: capturing energy from a star is one thing, transporting
it to where it can be used a different problem (as we even see today with
electric cars)

Or maybe they will just mine bitcoin with it, who knows

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TeMPOraL
Transporting energy from a star is simple: concentrating the light. The most
basic incremental design for a Dyson sphere would be a swarm of mirror
satellites.

How do we see energy transport problem with electric cars? That's only a
matter of the right sockets not being available. The power grid is there.

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raverbashing
Can the grid handle 10% of cars moving from gas to electricity? 50%? 90%?

Not to mention battery issues (range, charge time, safety, etc) which are
getting better, no doubt about it

It's not only a matter of having the right socket

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ajuc
It's complicated, for sure, and will need changes in the infrastructure.

But it has some advantages as well. Imagine 10 000 000 cars with 50 kWh battry
capacity each connected to the grid and letting 10% of their capacity to be
used for balancing of the network. If the grid has excess power - charge to
100%. If the grid lacks power - discharge to 90%.

That's 50 GWh of balancing capacity.

It basically solves the problems with unpredictability of most of the
renewable power sources.

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supernova87a
This isn't new. In fact the same authors already started a company called
Skycool that was featured here in a story like 2 years ago. It uses a special
coated/layered radiative plate that's specially tuned to an atmospheric
transparency window to dump heat to the sky.

The problem is that where this would be economically viable, you would
generally already choose to use solar panels for the electricity -- cheaper
and similarly/more efficient.

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Zenst
Whilst the raw efficiency of peltiers and solar panels weigh in the favour of
solar panels - this design just has to point to the sky. Which for some
situations, may make it more viable after all. Ships may be a use for this.

But then I'm not up to date on the state of play in peltier advances. I've
read some fascinating developments in rectenna's, though no efficiency numbers
jumping out. But something that could completely change this whole area of
electricity generating. Could this design be adapted to any new tech though if
something wow around the corner jumps out as being x better than the best
peltier. Maybe from what I can tell, but for now it has some niche uses
without a doubt, but you won't see them in your neibours back yard or roof
anytime soon if ever.

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delecti
So a thermoelectric generator? Saying this is using the "coldness of the
universe" is technically true, but it's a bit of a grandiose way of describing
the fact that nighttime is colder than day. It would be pretty neat to harvest
the natural nighttime cooling of panels though.

[https://en.wikipedia.org/wiki/Thermoelectric_generator](https://en.wikipedia.org/wiki/Thermoelectric_generator)

~~~
notimetorelax
I don’t think it’s grandiose at all, this TED talk explains the effect pretty
well [https://youtu.be/7a5NyUITbyk](https://youtu.be/7a5NyUITbyk)

Radiative cooling functions both during night and day.

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satori99
Not sure if it is mentioned in the video you linked, but a Stanford team has
been doing interesting research into this type of thing in recent years;

[https://news.stanford.edu/2017/09/04/sending-excess-heat-
sky...](https://news.stanford.edu/2017/09/04/sending-excess-heat-sky/)

[https://www.technologyreview.com/s/532826/material-cools-
bui...](https://www.technologyreview.com/s/532826/material-cools-buildings-by-
sending-heat-into-space/)

[http://web.stanford.edu/group/fan/](http://web.stanford.edu/group/fan/)

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p1mrx
Good thing the universe is expanding, or else the void would be overflowing
with photon waste from projects like this.

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inflatableDodo
Perhaps that's why it is expanding.

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jacobush
Oh... messing with the ontology. I like it.

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inflatableDodo
We'll probably find out eventually that the whole cosmic accelleration thing
is a side effect of the use of FTL drives by advanced civilisations.

edit - with pan-galactic tickets getting a little bit more expensive every
visit.

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TeMPOraL
Better than (minor spoiler for Cixin Liu's Three Body Problem trilogy) finding
out that the universe used to have many more dimensions, but in some past
wars, dimensionality reduction weapons were used.

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inflatableDodo
I just like the idea that somewhere out there in the universe, there is a
minor business envoy to the q'Zickl floating in a waiting lounge, complaining
that 'There's much less tentacle room these days than there was a millennia or
two ago when hopping business class to Miami. Yes, that Miami, the one in the
Horsehead Nebulae. I know, they've made the shuttle smaller due to the greens
regulating inertial mass per passenger again. I'd feed those greenshifters to
unts.'

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Florin_Andrei
So they're cooling the Earth to make energy.

You could imagine a dystopian sci-fi novel where "at the end of times" the
only source of energy available is this - slowly leech heat out of your planet
to make some energy. Decisions, decisions...

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taneq
I've always wondered if some far future civilisation grappling with the heat
death of the universe will judge me harshly for mixing hot and cold water
together just to make warm water.

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gwbas1c
I always thought someone would make a device that can suck heat out of the air
to make electricity.

(Kind of like a heat pump, only that it could completely power itself from the
heat in the air instead of needing to consume electricity.)

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derekdahmer
Electricity cannot be generated from ambient heat. There must be a temperature
differential.

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gwbas1c
Is that a physical limitation, like the speed of light? Or is that a
limitation of our current knowledge?

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Retric
That’s close to the same energy solar panels should produce from starlight.
So, hard to find a useful application.

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jws
Starlight plus airglow is at least 6 orders of magnitude below sunlight.
Granted, it goes all night, but it seems like 4 watts per square meter is
still 3 orders of magnitude above photoelectric gathering of starlight.

That 4 watt number comes from a confused paragraph and it is possible the
journalist broke some numbers while handling them.

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Retric
Yea, I was using 64 nanowatts * (1,000,000 making what assumptions?) = 0.064
watts vs a theoretical ~.001 from starlight.

It seems unlikely you could improve the system by 64,000,000 using ambient
temperature at night, operating extremely close to a theoretical maximum
regularly, and be cheap enough for 4w/m to be useful.

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pella
(research) Full Text :
[https://aip.scitation.org/doi/10.1063/1.5089783](https://aip.scitation.org/doi/10.1063/1.5089783)

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HillaryBriss
vis a vis global warning, would it be better to just let that energy go out
into the universe without harvesting it?

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dwg
Assuming there is a demand for energy (given) than generating energy to meet
that demand (e.g. by burning coal or gas) has a much larger negative impact I
would imagine.

It's sorta like capturing braking energy. This used to be dissipated as heat
but now can be turned into energy which improves MPG and therefore reduces the
need for fossil fuels, no?

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HillaryBriss
Thanks. I follow your reasoning. The "if" is key: will humanity just add, or
actually substitute, this source of energy?

