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  1. #1
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    co-current flow in a DX-evaporator



    Hi,

    I am reading technical and theoretical information about evaporators. Given a DX evaporator, can temperatures be crossed? To my understanding, no. I have not found more information about it in the forum.

    However, this link of SWEP says, for a co-current configuration: "At the end of the evaporator, where superheating takes place, the temperatures of the secondary medium and the refrigerant run the risk of crossing each other."

    Link: http://www.swep.net/refrigerant-hand...orators/asas6/

    Can someone confirm that statement is true?

    Regards,



  2. #2
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    Re: co-current flow in a DX-evaporator

    Hi mrr.
    I am somewhat confused what you are needing explained?
    Dx evaporators come in various styles.
    The ones being discussed don't refer to a secondary medium. But a secondary fluid!
    Ie shell and tube / plate heat exchangers.
    Basically the flows of the refrigerant and secondary fluid are specific and if incorrect flows apply.
    then cross over can occur!

    Grizzly
    Despite the High Cost of Living it still remains Popular!

  3. #3
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    Re: co-current flow in a DX-evaporator

    Hi mrr

    I think you are talking about a heat exchanger rather than an evaporator where refrigerant is on 1 side and a secondary working fluid is on the other.

    There is a calculation that will determine the amount of work done - it's called Log Mean Temperature Difference or LMTD for short.

    Here's a link where you can read up on the formula but do a search and there are lots of examples which should answer your question
    I'm back on the Pale

  4. #4
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    Re: co-current flow in a DX-evaporator

    Hi Grizzly and Frank,

    I refer specifically to evaporators were phase-change happens, as in Figure 6.13 of the link http://www.swep.net/refrigerant-hand...orators/asas6/

    Grizzly, can you explain how can crossover occur? Then the superheated refrigerant would be at higher temperature than the fluid to cool! I do not see how this can happen in a co-current configuration.

    Regards,

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