Sizing a Chiller Correctly:

Simple instructions to Assure Proper Cooling

The importance of selecting a correctly sized chiller cannot be downplayed. An undersized chiller will always be a problem-- never able to properly cool the process equipment. An oversize chiller will never be able to run at it’s most efficient level. Specify he correct size chiller and enjoy years of continuous, efficient service. If you would like help, feel free to give us a call. We do this all the time.

To size a chiller properly you first need to calculate the delta T between the inlet and outlet water (the change in temperature), and the rate of flow in gallons per minute (GPM). Measuring the delta T requires a thermocouple or thermometer. Check the water temperature of the water inlet line and the water outlet line, and subtract the numbers to compute how much heat the equipment is adding to the water.

To measure the flow rate of the water place a flow meter on the outlet
line of your equipment. If one is not available, simply measure the
time it takes for
the outlet flow to fill a five gallon bucket, and then
compute your gallons per minute (GPM) of flow.

Now that you have these two figures you need to calculate
how many BTU’s (British Thermal Units) your equipment
puts off. Here is the formula:

# BTU/ hour = 500
(the weight of water) x GPM x Temperature
Difference (delta T)

Repeat this for all the equipment you have, and add up the total BTUs. Now that you have the BTUs, lets compute the total Tons of cooling you need from a chiller. 1 Ton of cooling is 12,000 BTU/hour so...

# Tons = (BTU/hr) / (12,000)
This is the size unit you should need. There may be other circumstances, like planning for expansion, that would lead you to buy a different size unit. For more information about the specific units, follow the links below. business sense and positively effects your bottom line.



120 Nowlin Lane • P.O. Box 22847 • Chattanooga, TN 37422
(423) 894-6234 • 1-800-NOW-SNOW (800-669-7669) • FAX (423) 892-3889 • ORDER FAX (423) 490-2417
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