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Scanning the original paper linked by _Microft and rmbryan, it looks like the pressures the researchers used were very high, 0.25-0.5GPa. Maybe someone with more domain-specific knowledge can answer this: are such high pressures actually practical? My understanding is that one of the reasons R-744 (CO2) is not more common is that it requires high pressures, which means specialized equipment. But the pressures involved here seem to be an order of magnitude higher even than required with R-744.


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Here's the original paper: https://www.nature.com/articles/s41467-019-09730-9

This is all I saw to address the pressures required:

> Our higher operating pressures do not represent a barrier for applications because they can be generated by a small load in a large volume of material via a pressure-transmitting medium, e.g., using a vessel with a neck containing a driving piston, whose small area is compensated by its distance of travel.


I don't really have a good understanding for why the high pressures are required.

Any ELI 5 explanations?


At pressures of more than one million times Earth’s atmospheric pressure ? Totally academic, no real application in real world problems.

That is 1,5 to 1,6 million times atmospheric pressure...Slightly impractical?

AFAIK they don't use pressure vessels for pressures this high; they use diamond anvils.

The pressures we're talking about here are almost 2 orders of magnitude more than what is used to make diamonds.

> -140C only works for CO2-rich streams (> 10%).

The chart in the article by the link suggests -140C would work for pressure of 0,0004 atm.

How did you get that number - >10% ?


Couldn't they just use pressurized air?

Worse, they require temperatures/pressures far in excess of what's realistic any time soon, except possibly for very brief bursts in the lab.

The title definitely should have mentioned the pressure needed though. It's the difference between "revolutionary" and "probably no practical applications, but nice for academia I guess".

This is much lower pressure than those others. It's not that it's practical to make a useful device, but it is much more practical to do in a lab where researchers can analyze the structure and hopefully design new ones. So it might be a very useful stepping stone.

You're right. The concept is easier in off-world use where the atmospheric pressure is lower since that brings down the costs of the tube construction and pressurization.

edit: rewording


This one is at 10kpa. Nearly ambient pressure. If it’s for real, it’d be an historic breakthrough.

> up to 800 MPa

The words “up to” would imply lesser pressures would work.


It's both high concentration, and high pressure.

The machinery is very expensive and DIYing something with those pressures is very dangerous, since you're building a bomb. That's about 2000x the pressure inside a champagne bottle and 20x the pressure of a bomb.

Pressure that is well within humanity's capability to produce and maintain at small-ish scales (not intercontinental transmission lines, but within a factory). 100x less pressure than the previous record. If these results were real, it would absolutely be an enormous scientific leap forward and lead to new technologies, and I don't see a reason to minimize that. Of course, it's all fabricated bullshit, so I guess it's a moot point.

Isn’t nitrogen cooling much easier to achieve than this level of pressure?

According to other posters, liquid CO2 can be stored at 5 atm pressure which is trivial from an engineering POW.
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