Chiller Sizing Rules of Thumb

Properly sizing a chiller for your application can depend on a large number of variables.  For over 40 years our team at COLD SHOT CHILLERS have successfully sized, quoted, and built machines for many applications

Chiller Size Calculator

We have developed and adopted numerous “rules of thumb” to assist our customers in their quest for cost effective, efficient cooling solutions.  We have shared these “shortcuts” on pages on our site for your convenience.  We have an experienced team waiting to assist you with your specific requirements.  Please feel free to call or email any specific needs and we will promptly reply to your request.

Plug in the following three inputs into the calculator below to get the estimated chiller size you need for your application.

  • The incoming water temperature
  • The chill water temperature you require
  • The flow rate

General sizing formula:

  1. Calculate Temperature Differential (?T°F) ?T°F = Incoming Water Temperature (°F) - Required Chill Water Temperature
  2. Calculate BTU/hr. BTU/hr. = Gallons per hr x 8.33 x ?T°F
  3. Calculate tons of cooling capacity Tons = BTU/hr. ÷ 12,000
  4. Oversize the chiller by 20% Ideal Size in Tons = Tons x 1.2
  5. You have the ideal size for your needs

For example, what size chiller is required to cool 40GPM from 70°F to 58°F?

  1. ?T°F = 70°F - 58°F = 12°F
  2. BTU/hr. = 40gpm x 60 x 8.33 x 12°F = 239,904 BTU/hr.
  3. Ton Capacity = 239,904 BTU/hr. ÷ 12,000 = 19.992 Tons
  4. Oversize the chiller = 19.992 x 1.2 = 23.9904
  5. A 23.9904 or 25-Ton chiller is required

There also industry specific rules of thumb for chiller sizing depending on your application:

Unsure what size chiller you need? Cold Shot Chillers is here to help. Contact us and we will work with you to determine the ideal sized chiller for your custom application.

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