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  1. #1
    Join Date
    Jun 2016
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    Egypt
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    Condensing Unit selection ?



    Can someone help me to select the right condensing unit that fulfills the following specification :

    Capacity=.8 KW (I think it's too low put my application to cool 5 litres of antifreeze to -20C)

    Evaporating temperature=-25C
    Condensing temperature=40C

    Superheat=10
    subcooling=10 these two are recommendations and can be changed if I am wrong?

    I am using coolpack to get the cycle information for R-22 and R404A

    The Refrigerant: R22
    Data:
    Te [C] = -25.00
    Tc [C] = 40.00
    DT subcooling [K] = 10.00
    DT superheat [K] = 10.00
    Isentropic efficiency = 1.00
    -------------------------------------------------
    Calculated:
    Qe [kJ/kg] = 165.098
    Qc [kJ/kg] = 219.861
    W [kJ/kg] = 54.763
    COP [-] = 3.01
    Pressure ratio [-] = 7.630


    Refrigerant: R404A
    Data:
    Te [C] = -25.00
    Tc [C] = 40.00
    DT subcooling [K] = 10.00
    DT superheat [K] = 10.00

    -------------------------------------------------
    Calculated:
    Qe [kJ/kg] = 115.920
    Qc [kJ/kg] = 158.189
    W [kJ/kg] = 42.270
    COP [-] = 2.74
    Pressure ratio [-] = 7.266
    -------------------------------------------------


    As you can see the cop for R-22 is higher and it's price is much less than R404A
    but when I go to http://www.embraco.com/catalog/Default.aspx?language=EN
    to select a condensing unit as they are available in my country if found the evaporating temperature for R22 is ranging from -15 to 10C ?

    Can someone please help me cause I am not an expert if something i don't understand please tell me.



  2. #2
    Join Date
    Sep 2003
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    ISRAEL
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    Re: Condensing Unit selection ?

    I think this unit will be ok for your application - UC UNT2180GK 220V/50Hz 515301512

    I would use 507 as refrigerant, you can use also 22 with the same condensing unit.

  3. #3
    Join Date
    Jun 2016
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    Re: Condensing Unit selection ?

    Thank you for your answer I really appreciate.

    In the product specification, the refrigerant is 404A is that alright? Can I use another refrigerant while the specification recommends a specified one?

    One more think if you excuse me
    do you use the website (http://www.embraco.com/catalog/Default.aspx?language=EN) for selection or you go to pdfs catalog?

  4. #4
    Join Date
    Sep 2003
    Location
    ISRAEL
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    Re: Condensing Unit selection ?

    You can use 404, 507 or 22. Just make sure that oil is POE. With 22 you will get lower discharge pressure.

    I use my supplier web page for selection.

    Good luck with your project.

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