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  1. #1
    i need a easy way to figure gpm on my primary chilled water loop. any ideas i have asked this before and never really got a good answer.

  2. #2
    Join Date
    Feb 2005
    Posts
    344

    GPM

    The components such as pumps, chiller barrel, etc in the primary should give you gpm for a given pressure drop.

    Good look...


  3. #3
    Join Date
    Apr 2005
    Location
    where the beer flows like wine
    Posts
    2,871
    why dont you install a gpm meter?

  4. #4
    Join Date
    Mar 2004
    Location
    New England
    Posts
    224
    Every pump has a curve.Use good gauges.
    An apprentice is half a journeyman ,two apprentices is a call back.

  5. #5
    Join Date
    Jun 2004
    Location
    BR,LA
    Posts
    256
    why don't you search this forum for past questions regarding finding GPM !

  6. #6
    Join Date
    Feb 2005
    Posts
    69
    Originally posted by chillered
    i need a easy way to figure gpm on my primary chilled water loop. any ideas i have asked this before and never really got a good answer.
    ...what part of the loop do you want? Usually the main concern is across the barrel or cooling units.

  7. #7
    Join Date
    Dec 2002
    Posts
    603
    Originally posted by chillered
    i need a easy way to figure gpm on my primary chilled water loop. any ideas i have asked this before and never really got a good answer.
    For design conditions it's: CHILLED WATER TON = GPM x ÄT x 0.4167 or GPM = 24 x TONS / ÄT

  8. #8
    Join Date
    Nov 2004
    Location
    Practically Canadian ehh.
    Posts
    675
    Contact the chiller manufacturer and request a flow curve for your chiller. You will need to determine pressure drop across the evaporator then plot it on the flow curve. This should tell you the gpm through the chiller evaporator. Pump curves will also work if you don't have pressure gauges or ports at the evaporator. Try to use the same gauge for both pressure readings and make sure the gauge is good. Most flow curves will read in FT of Water or Ft Head. You can convert your pressure drop (or delta P) to Ft by multiplying times 2.31.

    ex: 10 x 2.31 = 23.1
    ÄP x 2.31 = Ft H2O


    Hope this helps.


  9. #9
    Join Date
    May 2004
    Location
    Illinois
    Posts
    2,843
    Originally posted by chillered
    i need a easy way to figure gpm on my primary chilled water loop.
    Just to clarify..

    Are you wanting to know how many GPM you need for a certain size chiller, or are you looking for a way to measure what you've got?

    1. 2.4 GPM/Ton @ 10º dT.
    2. Pressure drop across barrel.
    "If I had my life to live over again, I'd be a KA." - Albert Einstein

    It's later than you think.

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