995
Heat (lemmy.ca)
submitted 6 months ago by to c/science_memes@mander.xyz
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[–] 17 points 6 months ago (8 children)

A heat pump will drop to 100% efficiency in cold enough weather.

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  • [–] 2 points 6 months ago (7 children)

    Can heat pumps drop below 100%?

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  • [–] 2 points 6 months ago (6 children)

    They can drop all the way to 0 if the temperature difference is high enough. You can't heat your house with a heat pump if it's 0K outside.

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  • [–] 2 points 6 months ago* (4 children)

    Heat pumps generally come with an electrical resistive backup in case it's too cold outside, so even at arbitrarily low temperatures a heat pump can only drop to 100%

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  • [–] 3 points 6 months ago (3 children)

    At that point, the heat pump is off and you're using a resistive heater. You can't just glue an LED to an incandescent lightbulb and call it a 50% efficient incandescent lightbulb.

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  • [–] 3 points 6 months ago (1 child)

    True. You know, the moment I left that comment, I thought that was pedantic, I shouldn't have said it, but by that point if I had deleted it it would just sit there saying deleted forever and that would bother me even more

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  • [–] 1 point 6 months ago

    Heat pump could heat your house if it's near 0K "outside". Heat pumps are how we chill to near 0K anyways. And by heat pump I mean literally a window air conditioner. Replace the freon in your typical AC with helium and get a really fancy evaporator (cold head or cold finger is the trade term) and you could probably get a 10cc vial on the end to sub 70K. With vacuum and a bigger 240V window AC unit you can get near 4K. Running multiple heat pumps in stages and with liquid nitrogen as coolant for some of them and you can condense helium and push really close to 0K.

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