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Basic: Rule of Thumb for Newton's Cooling for ACs

  1. Aug 23, 2015 #1

    WWGD

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    Hi, just curious:
    Is there a nice rule-of-thumb to apply Newton's cooling to ACs? Specifically, if I know the AC temperature is , say 60 deg. , how long will it take, after I turn off the AC, before thetemperature rises to an unacceptable level of 85 degrees?
    Thanks.
     
  2. jcsd
  3. Aug 23, 2015 #2

    Bystander

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    If your thumb feels warm, it's probably no longer 60 F. Practically, without knowing anything about thickness of insulation, or ambient temperature, you can say nothing.
     
  4. Aug 23, 2015 #3

    WWGD

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    Thanks, is there a formula/rule of thumb in function of those two variables?
     
  5. Aug 23, 2015 #4

    Bystander

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    (Area exposed to ambient temperature times temperature difference between ambient and system) divided by (thickness of insulation times heat capacity of system) in appropriate units.

    Large, well insulated systems cool/warm slowly, and small, poorly insulated systems cool/warm quickly.

    Are we talking about bait buckets or meat lockers?
     
  6. Aug 23, 2015 #5

    WWGD

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    Thanks, sort-of in-between . My AC goes down to around 61, I have your average apartment, 2nd floor. I think insulation is average. I will look it up, thanks.
     
  7. Aug 23, 2015 #6

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    Sunny side? Neighbors overhead?
     
  8. Aug 23, 2015 #7

    WWGD

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    Ah, sorry and thanks again. I have a small window facing sort-of inner garden, around 15' x 15' facing the north side, and it faces another building, i.e., there is a small garden separating my apartment from a 5-story building. No other windows I have 5 stories above me, one below, and and I don't get much direct sunlight. Strangely-enough, the place remained warm in Winter with little, if any heating, but the reverse is not so in Summer, the place is very humid and hot.
     
  9. Aug 23, 2015 #8

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    Neighbors below, behind, and to either side are elderly?
     
  10. Aug 23, 2015 #9

    WWGD

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    Ah, sorry again. Neighbors to the right, to the left, top and bottom, but not behind. I don't think are elderly, pretty sure not, but not 100% but how does that make a difference?
     
  11. Aug 23, 2015 #10

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    There is a tendency for older folks to run their living spaces slightly warmer. Just thought your AC might be having to fight someone's rheumatism.
     
  12. Aug 23, 2015 #11

    WWGD

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    I see. Thanks for your patience and sorry for my slowness. I will be out for a run for around an hour just in case.
     
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