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Calculating Chilled Water Flow


How to Calculate GPM Through a Chiller Cooler.

1.     First determine the capacity of the machine a %100 load. Example 20 tons

2.     Measure the temperature drop through the cooler at %100 capacity. Example: Entering chilled water is 60 degrees, minus 48 degrees leaving chilled water = 12 degrees

3.     Use the following formula-  Tons × 24 ÷ Delta T = Gallons per minute

 Example- 20×24= 480 ÷ 12 = 40 Gallons per Minute (GPM)


+4 # jameel 2013-06-23 06:33
hai I saw this calculation.( How to Calculate GPM Through a Chiller Cooler)

Use the following formula- Tons × 24 ÷ Delta T = Gallons per minute
I agree this I need definition about all

ton= cooling capacity
Delta T= chilled water temperature difference
GPM = Gallons per minute
24 = ?... can you explain me
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+2 # Patrick Peterson 2013-06-27 21:54
The 24 refers to hours in a day.

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+1 # Rodney Hamby 2013-07-23 20:02
Hi Patrick.

Is this equation valid for condenser barrels as well?
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0 # Patrick Peterson 2013-07-23 21:27
Great question!
It would be great if it could, but unfortunately, it can't. (except for open drive, centrifugal chillers)
The reason; the condenser barrel is not only rejecting the heat from the load, it also has to reject motor cooling heat for compressor motors that are refrigerant cooled (not open drives) and the heat of compression for positive displacement compressors such as screw, reciprocating and scroll compressors.

Stay tuned though, in the upcoming weeks we'll talk about approach temperatures; really good stuff to know if you're a chiller tech.

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