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by lloeki 6 hours ago
Can't read the article (paywalled) so I'm basing myself on what I see

> Green electricity means never having to say sorry for lowering the thermostat

I literally just read some reports yesterday day about how AC can be a pathological solution.

It's not about the energy being green or not, it's that independently of the energy source AC is a heat pump, so it pumps heat out into the air, which makes the air inside cooler, but hotter outside; and for that, green or not, it needs to put in energy to do the work, which results in _even more heat_.

At scale a.k.a cities this creates measurable bubbles of heat (+1-2degC) around AC'd places.

As Desty Nova puts it in Gunnm (a.k.a Battle Angel Alita):

    Now becomes the past in an instant — and everyone will eventually die! Destiny triumphs over human knowledge and goes mad! That is the way of things! I spit upon this frail, crazed, world! I spit upon the Second Law of Thermodynamics!
3 comments

> I literally just read some reports yesterday day about how AC can be a pathological solution.

That's what I have been wondering as well. When I was in Japan (which is notorious for using obscene amounts of AC), I once walked past the rear side of some buildings where all the AC vents were and you could clearly feel the heat these things are pumping into the city. How is this not creating a feedback loop?

> It's not about the energy being green or not, it's that independently of the energy source AC is a heat pump, so it pumps heat out into the air, which makes the air inside cooler, but hotter outside; and for that, green or not, it needs to put in energy to do the work, which results in _even more heat_.

What? If things would have worked as you say, we would have solved global warming in no time. Just open the windows and blow the cold air out and keep the inverter inside.

> If things would have worked as you say

They work _exactly_ as I say:

https://en.wikipedia.org/wiki/Heat_pump_and_refrigeration_cy...

https://en.wikipedia.org/wiki/Second_law_of_thermodynamics

> Just open the windows and blow the cold air out and keep the inverter inside

This "just" seems to hint that you don't seem to quite be grasping the concepts and scale at hand:

- Assuming perfect efficiency and unlimited free energy, where would you even put the heat from outside?

- Since energy is neither free nor unlimited, the energy needs would be enormous+

- Since it is not perfectly efficient and the energy needs are so high, the amount of wasted energy (which is heat) would be colossal, and only make the problem worse

+ The heat causing global warming comes not from human activity but from the sun, the anthropogenic effect at play is that this energy from the sun is captured by greenhouse effect.

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