this post was submitted on 09 Oct 2024
207 points (95.6% liked)

Futurology

1812 readers
56 users here now

founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 17 points 1 month ago* (last edited 1 month ago) (5 children)

The work addresses the thorny problem of waste heat. Thanks to the second law of thermodynamics, a small amount of heat will always be released into the planet's atmosphere no matter what energy source we use — be it nuclear, solar, or wind — because no energy system is 100 percent efficient.

"You can think of it like a leaky bathtub," study coauthor Manasvi Lingam, an astrobiologist at the Florida Institute of Technology, told LiveScience. A small leak in a bathtub that's barely filled doesn't let out a lot of water. But as the tub continues to get filled — and our energy demands grow — that tiny leak can flood the whole house, Lingam explained.

I thought the problem was that CO~2~ was acting like a blanket trapping in all the heat. Is this "heat leaking" really a problem? If so, what about solar cells then?

[–] [email protected] 21 points 1 month ago* (last edited 1 month ago) (1 children)

Nothing we do is 100% efficient, everything produces heat - CPUs pretty much make all their energy into heat

Heat can't travel good in a vacuum. So it can only radiate of, which isn't really effective

So just by using all our infrastructure, we would cook ourselves in there future.

The CO2 blanket only accelerates it much more

[–] [email protected] 8 points 1 month ago

Thank you for explaining. That was the context I was missing.

[–] [email protected] 16 points 1 month ago* (last edited 1 month ago)

Is this “heat leaking” really a problem?

Not yet. We'd need another century or two of energy consumption growth before it becomes really significant. The CO~2~ thing is actually very specific to our current way of generating power and avoidable - they conflated it a bit in the headline, probably for clicks.

Fundamentally, economic growth on Earth (probably, barring new physics) can't continue forever. It's a finite lump of matter, there's finite ways of arranging it, and one or more arrangements will be the best while still respecting things like thermodynamics. Once we get there, there's nothing to improve.

[–] filcuk 1 points 1 month ago (4 children)

Heat exchangers have >100% efficiency.
We just need to use those to move the extra heat outside the environment.

[–] [email protected] 3 points 1 month ago* (last edited 1 month ago)

This shouldn't be downvoted; it's a good point. I actually do expect that in a distant future that's positive, it would make sense to add artificial heat exchangers to the Earth.

The trick is that vacuum is a really good insulator, and theoretical maximum heat pump efficiency sinks down to "just" 100% gradually as the temperature gap gets larger. In order to move more heat, you have to make the heat exchangers pointed at the night sky hotter, so at some point you're bound to get diminishing returns.

[–] [email protected] 3 points 1 month ago

The way they have >100% efficiency is if you are trying to increase the temperature, you can create new heat (which is extremely easy and can be done with essentially 100% efficiency) or you can move heat from elsewhere (creating new heat in the process as well, so it ends up being over 100% efficiency).

These incredibly high efficiency rates come from interpreting heat as success. It’s very easy to add heat to a system. It’s very hard to get rid of it.

Any system that moves heat from one area to another must necessarily produce more heat as well.

When your refrigerator cools your food, it vents hot air, adding more heat to the outside world than it removed from inside itself.

[–] [email protected] -4 points 1 month ago (1 children)

Nothing in the universe has an efficiency over 100%.

[–] [email protected] 6 points 1 month ago* (last edited 1 month ago)

Depends how you define it. Heat exchangers do, because it's defined for them in terms of heat moved per heat generated. All conservation laws are still respected.

[–] [email protected] -3 points 1 month ago

It is, they're grasping at straws