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Why are ice chests not vacuum insulated?

  1. Jun 12, 2017 #1
    Aside from vacuum flasks and vacuum insulated panels, there doesn't seem much else vacuum insulated. Why are there no ice chests vacuum insulated?

    My uneducated guesses as to why ice chests are not vacuum insulated:
    1. Cost to vacuum insulate.
    2. The cylindrical shape of a flask offers greater pressure strength.
    3. Ice chests take a much greater beating than flasks.
     
  2. jcsd
  3. Jun 12, 2017 #2

    mfb

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    Large flat areas don't work well with vacuum, you would need cylinders, that is less practical. And you still have the bottom and the top - you probably don't want to make a sphere.

    I'm not sure which price customers would pay for a better insulation. If the ice lasts long enough anyway, you don't gain much.
     
  4. Jun 12, 2017 #3
    Ah, thank you for the informed reply.

    If there is little gain for vacuum insulating (flasks), why do they even bother vacuum insulating flasks (assuming it's comparable to an ice chest)?
     
    Last edited: Jun 12, 2017
  5. Jun 12, 2017 #4

    Bandersnatch

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    Dewars are used where high insulation efficiency is required, or other methods of insulation are deemed undesirable.
    For an example of the former, you wouldn't want to pay dearly for a bulky dewar to keep your beer chilled, but you might want to reconsider if you're worried about your liquid helium staying liquid.
    For the latter, when chilling beer you can rely on large heat capacity of a few pounds of ice in your ice chest in spite of its average insulation, but you need good insulation whenever carrying ice with you is not an option (e.g. it's ok to bring a thermos to a management meeting, but an ice chest could be risky).

    Liquified gas pipelines, cryostats, superconducting magnets - pretty much all cryogenics industry is built on vacuum insulation.

    All in all, I think the OP identifies the issues pretty well. It's a simple cost-benefit calculation.
     
  6. Jun 12, 2017 #5
    :) Thank you very much. I have a much greater understanding.
     
  7. Jun 12, 2017 #6

    anorlunda

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    image.jpeg

    Flat vacuum panels are used in refrigeration. So why not an ice chest? But they are expensive and delicate.
     
  8. Jun 12, 2017 #7
    I've read somewhere that the vacuum panels are vacuumed at 100 torr while the vacuum flasks are at 0.001 - 0.00001 torr. I wonder if the difference is that noticeable..?

    Edit: Hmm, the panels you've shown have an internal vacuum at lower than 0.0075 torr, according to the manufacture.
     
    Last edited: Jun 12, 2017
  9. Jun 12, 2017 #8

    anorlunda

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    All I know is that they insulate better than foam, and if you accidentally out a hole in them, you're dead.
     
  10. Jun 12, 2017 #9
    :) Yeah. The tests they do with the YETI ice chest to demonstrate durability by throwing them off a cliff, I suppose would be a bad idea.
     
  11. Jun 12, 2017 #10

    JBA

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    At the same time, as a hiker in the high temperatures of the southwest region of the USA I have wondered why they do not use a hard shell and vacuum, rather than the soft shells used on so called "insulated" water bottles. The standard metal/glass thermos bottle's weight penalty essentially makes them useless for hiking water bottles.
    I considered evacuating one of the flexible shell bottles and replacing the air with with helium (I assumed less density = better insulation) but a little study revealed that the thermal conductivity of a gas has little to do with its density. Both hydrogen (k=.0966) and helium (k=.0818) have very high transfer coefficients. On the other hand, Chlorine (k=.0043) and Sulfur Dioxide (k=.005) gas have the lowest heat transfer coefficients but clearly have safety problems; but, CO2 (k=.0084) might be a good choice.
    For reference air is k=0.0140. All values at 32°F.
     
  12. Jun 13, 2017 #11

    anorlunda

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    Argon
     
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