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Thread: Availability?

  1. #1
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    Availability?



    I'm looking to buy a freezer for doing a -10C lifetime test on a product that generates 175W. What I want to do is calculate the available cooling capacity for potential refrigeration units, given their input power and COPs.

    My current modeling approach is basically a constant temperature reservoir (ambient), a cyclic machine, and a fixed volume of air. I've got an expression for the cooling power in terms of the input power to the cyclic machine, the thermal mass of the volume, temperatures, and entropy generation.

    I imagine to calculate the margin I have in terms of cooling capacity, I need to know what my entropy generation (and subsequently, exergy destruction) is. I'd have to think that this is tied to the COP of the system, so is there a way to calculate this exergy destruction from the COP?

    Also, if my approach is wrong, please let me know.

    Thanks all



  2. #2
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    Re: Availability?

    Let me clarify, I'm doing this so I will know if the refrigeration unit I buy will be able to maintain the -10C environment with 175W of heat generation inside.

  3. #3
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    Re: Availability?

    COP = cooling/power input
    Cooling = COP * power input.
    But I do not know of a freezer who's rating is based upon -10C
    You can not use this as the only method, as the freezer capacity includes the gains into the freezer.
    Last edited by mad fridgie; 02-02-2012 at 10:29 PM.

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