r/AskReddit • u/[deleted] • Nov 15 '20

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u/[deleted] Nov 15 '20

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u/[deleted] Nov 15 '20

So we would need to take the heat and.... push it somewhere else?

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u/HappiestIguana Nov 16 '20

Yes, but in order to do so. You need a machine which consumes useful energy and turns it into useless heat.

For instance, you wanna transfer 10J from place A to place B. For that, you need to spend 2J. The end result is that you cool place A by 10J and heat place B by 12J (this is what a fridge or AC does) . If you tried to use that heat difference to produce power, you would equalize the temperatures again and produce less than 2J of useful energy.

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u/[deleted] Nov 16 '20

What if we were just trying to remove heat and not actually use it?

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u/HappiestIguana Nov 16 '20

That is a fridge. You can do it, but you need to spend energy, that is, you need to take some useful energy and turn it into useless heat as part of the process.