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Thread: confused?????

  1. #1
    stocky07's Avatar
    stocky07 Guest

    confused?????



    I am new to this site and new to HVAC. I am a student at local communiity college taken HVAC course. I thought I understood material until I got home and drew a blank. I am hoping someone can help me understand how to use certain formulas for calculating. EX.

    Given: R-22
    evap. outlet superheat = 10 f
    evap. outlet temp. = 50 f
    cond. pressure = 246.1 psig

    Find: evap saturation temp. =
    evap pressure =
    condensing temp. =
    amb.temp. =
    if subcooling = 12 f, the cond. outlet temp. =

    This is my second day of class. The biggest problem is trying to digest 7hrs of class information. I have to deal with it until Nov; I will never take such a long class again,it's too much but I will succeed. Can someone help me understand this proplem?



  2. #2
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    Re: confused?????

    A few hints

    Te,sat (evap sat press)= outlet temp - SH
    At Te,sat => find evap saturation pressure
    At cond. pressure => Tc,sat (cond sat temp)
    Amb. temp = anyone? (Suspect an approach, or TD may be required here - off either evap, or cond?)
    Cond outlet temp = Tc,sat - SC
    Last edited by desA; 19-09-2012 at 09:08 AM.
    Engineering Specialist - Cuprobraze, Nocolok, CD Technology
    Rarefied Technologies ( SE Asia )

  3. #3
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    Re: confused?????

    Quote Originally Posted by stocky07 View Post
    I am new to this site and new to HVAC. I am a student at local communiity college taken HVAC course. I thought I understood material until I got home and drew a blank. I am hoping someone can help me understand how to use certain formulas for calculating. EX.

    Given: R-22
    evap. outlet superheat = 10 f
    evap. outlet temp. = 50 f
    cond. pressure = 246.1 psig

    Find: evap saturation temp. =
    evap pressure =
    condensing temp. =
    amb.temp. =
    if subcooling = 12 f, the cond. outlet temp. =

    This is my second day of class. The biggest problem is trying to digest 7hrs of class information. I have to deal with it until Nov; I will never take such a long class again,it's too much but I will succeed. Can someone help me understand this proplem?
    You will need a chart, comparitor or even a new phone app to
    work out what pressure a refrigerant will be at a given temp
    or visa - versa

    A clue cond. pressure = 246.1 psig is about 113degf
    With that information everything should drop into place.

    Regards

    Rob

    .

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