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Comment by 988747 | Hacker News Reader

Finally! Now we can have an air conditioner that does not require a pipe to blow the hot air outside. Like truly mobile unit.

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Unfortunately we'll always need the pipe to blow air outside. The heat has to go somewhere. Even with this invention, if they're converting heat to electricity, they will have to release at least as much heat as they converted to electricity.

Indeed, this can be demonstrated by running current through a plain old Peltier cooler without a big chunky heat sink attached. At first the cooler will have one side heat up and the other side get quite cold, but within a few minutes the entire block becomes evenly warm.

Eh, doesn't all modern air conditioner just do heat exchanging? no need to actually blow the air out - but yes you still need a pipe for the heat exchanging medium

That’s thermodynamically impossible.

Why? You could theoretically take out energy from the room in the form of electricity

You can’t. The second law of thermodynamics prohibits it.

“It is impossible to devise a cyclically operating device, the sole effect of which is to absorb energy in the form of heat from a single thermal reservoir and to deliver an equivalent amount of work.”

How does having a hot side of a piece of material and a cold side of a piece of material come under "cyclically operating"?

Perhaps not an equivalent amount of work, but if we could capture some of the waste....

Not true.

For example you could convert the heat into photons (infrared radiation) and beam that out of the room without needing a pipe. You would probably need an infrared transparent patch on the window to aim at.

https://spie.org/news/5129-a-metamaterial-to-convert-heat-to...

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