A new heat engine with no moving parts is as efficient as a steam turbine

Re:A new heat engine with no moving parts is as efficient as... by bumby on Thursday April 14, 2022 @10:18AM (#31027373)

>The heat pump itself is >100% efficient

Are you sure you aren't confusing the coefficient of performance with the efficiency? If a heat pump was >100% efficient, I could cool my house by leaving my refrigerator door open.

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Re:A new heat engine with no moving parts is as efficient as... by hnuser123456 on Thursday April 14, 2022 @12:11PM (#31028896)

If you pipe the heat from the compressor directly outside instead of venting it into the same room, that would work.

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Re:A new heat engine with no moving parts is as efficient as... by bumby on Thursday April 14, 2022 @12:54PM (#31029619)

Correct, that's what refrigerated air conditioners do. But that's really just playing a trick with the system boundary in the problem; it doesn't mean the global efficiency has exceeded 100%.

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Re:A new heat engine with no moving parts is as efficient as... by cormacrelf on Thursday April 14, 2022 @11:08PM (#31036271)

Yes, it's an imprecise term.

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Re:A new heat engine with no moving parts is as efficient as... by bumby on Sunday April 17, 2022 @11:44AM (#31061629)

To be clear, I don't think the term is imprecise. Efficiency is always (work out)/(work in). The numbers get wonky when we aren't fully accounting for the "work in". In the case of refrigeration, we have to account for the work it takes to compress the fluid and the resulting waste heat.

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