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  1. #14
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    when i am talking to a hvac tech. im talking "Tons" and operating pressure.

    when i am talking to a reefer tech. im talking HP. and coils temperature.
















    which language does heat transfer professionals talk??





    Don't interrupt me while i'm talking to myself

  2. #15
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    Aug 2002
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    I'm full a time "Market Man" and I'm dumb as hell.

    I'm a likin' this thread though

  3. #16
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    Apr 2005
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    In general there is a rule of thumb that can be applied when nothing but horsepower is known.

    1 hp at a/c temp is around 1 ton or 1:1
    1 hp at med temp is around 2/3 ton or .66:1
    1 hp at low temp is around 1/3 ton or .33:1

    This is really general but can get you pretty close when no other info is available. (destroyed or unreadable tags are the norm) Or when someone forgets to tag the orifice size that's inside of a tx valve.

  4. #17
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    Mar 2005
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    Heat Transfer Professionals ....I just found the name for my new company !!!!Thanks !!!!H. T. P. May I help You.... What do you think??? ... Any way...I found the information in this thred very helpful and quite interesting however it brings up a question. How or should you also factor in the refrigerant type and its specific heat value in to the equation when figuring compressor capacity of heat transfer at certain saturated condtions?

  5. #18
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    Sep 2002
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    Originally posted by richper
    Heat Transfer Professionals ....I just found the name for my new company !!!!Thanks !!!!H. T. P. May I help You.... What do you think??? ... Any way...I found the information in this thred very helpful and quite interesting however it brings up a question. How or should you also factor in the refrigerant type and its specific heat value in to the equation when figuring compressor capacity of heat transfer at certain saturated condtions?

    By ploting the particular system on a PH or Mollier diagram for that particular refrigerant.


  6. #19
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    Sep 2005
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    so what is

    the right answer?

  7. #20
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    Nov 2004
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    Re: so what is

    Originally posted by air2spare
    the right answer?
    evaporator and condensor conditions determine the horse power need to provide a ton of refrigeration from a given compressor...

    what was the question?

  8. #21
    Join Date
    Feb 2004
    Location
    Medford Oregon
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    12,000 btuh = 1 ton
    no HP relationship to btuh

    CF12K6E-TF5
    130 Condensing
    -20 Evap 7070 btuh
    -10 Evap 10200 btuh
    -5 Evap 12000 btuh (nominal rating)
    0 Evap 13900 btuh

    110 Condensing
    -20 Evap 10700 btuh
    -10 Evap 14800 btuh
    -5 Evap 17100 btuh
    0 Evap 19700 btuh

    different for other cond and evap temps, where are you at ?

    get a performance sheet from Copeland Wholesaler to
    see ratings at other conditions

    Sorry, you cannot relate HP to ton or btuh
    (never was true, that was an old wife's tale)

  9. #22
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    Sep 2002
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    South Dakota
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    rocket is correct. It is all about volumetric efficiency. The higher the head pressure and the lower the suction pressure, the lower the cooling capacity (tons) at the same HP.

    Actually, as the head pressure increases and the suction pressure decreases the BHP increases while the capacity decreases.


  10. #23
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    Sep 2005
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    Texas
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    Im done

    Originally posted by NormChris


    rocket is correct. It is all about volumetric efficiency. The higher the head pressure and the lower the suction pressure, the lower the cooling capacity (tons) at the same HP.

    Actually, as the head pressure increases and the suction pressure decreases the BHP increases while the capacity decreases.


    (^%$%$*&*&%#@%%&_()*(*%^%#@#%^^%**)
    over and out

  11. #24
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    Sep 2004
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    [QUOTE]Originally posted by gerryboy00
    [B]when i am talking to a hvac tech. im talking "Tons" and operating pressure.

    when i am talking to a reefer tech. im talking HP. and coils temperature.

    which language does heat transfer professionals talk??



    It depends on what the professional is doing. If he talking about capacity, then its usually tons or btuh. If he needs to match a motor to an open drive compressor, then its horsepower. If its a comparison of efficiency/cycles, then it could be bhp/ton. It is rare that a proffessional would ever interchange one for the other unless done in purely thermodynamic terms where there is a direct conversion of btuh to hp and visa-versa.

  12. #25
    Join Date
    Dec 2004
    Location
    Sunny So Cal!
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    who's got time to sit and chat w the A/C guys at a parts house? I only notice them when its a demo day and they've eaten all the carne asada....and yesterdays donuts too....
    OK, so whats a little "home by 7 pm" envy eh?

  13. #26
    Join Date
    Dec 2003
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    The way I have always known it is according to the application (Low, Med, High) the electric motor in the compressor is the determining factor for hp, For example:

    4000 btu's at -10* evap 120 cond (Low temp)needs a 1hp motor(1hp compressor)to run efficiently at these conditions with the correct designed displacement.

    8000 btu's at +20* evap 130 cond needs a 1hp motor (1hp compressor)to run efficiently at these conditions with the correct designed displacement.

    12000 btu's at +45* evap 130 cond needs a 1hp motor (1hp compressor)to run efficiently at these conditions with the correct designed displacement.

    12000 btu's is and will always be "One Ton" of cooling no matter the application.

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