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Design thermal container

  1. Mar 2, 2016 #1
    Hello everyone, first of all, thank you very much for reading.

    I have to design a container (100 mm of height and 80 mm of interior radius of XPS) to keep a cryogenic mix (water and salt ice) at -15ºC at least for 40min. And my problem is to calculate the optimum thickness of XPS.

    I've been reviewing thermodynamic and heat transfer theory. I have conduction and convection so if I increase the thickness, I improve conduction but it's not good for convection. Also, I don't know how to connect the thermodynamics and heat transfer theory with warming the ice. I'm having some problems with the convection coefficient too.

    If somebody could help me I would be very grateful. Thanks!
  2. jcsd
  3. Mar 2, 2016 #2
    I tell you what I have do at the time.

    With specific heat of the mixture, the mass and the temperature difference between exit refrigerator temperature and -15ºC I calculate the heat.
    On the other way, I obtain the heat of convection and conduction with the equivalent resistance (in a cylinder), and finally, I equalize at the previous heat.
    I could calculate the exterior radius if it were not for the convection coefficient and the external temperature of the cylinder. And I can't give the time which I want (40min.)

    Any idea? Thanks!

    *Edit: -15ºC is the melting point of the cryogenic mix, therefore I can add the latent heats of fusion.
    Last edited: Mar 2, 2016
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