Chiller Calculation, Chilled Water Flow Rate Calculator, GPM Calculator

Chiller calculation

Hello engpocket friend, anyone of you worked in HVAC ME Contractor or in industrial?

You must know and familiar with chiller units. In this post, we will show you how calculate chiller GPM and also provide you the calculator.

The relationship between chiller & GPM

Calculating GPM (Gallons Per Minute) is a method to determine the required water flow rate to transfer heat effectively in a chiller water system. Based on our calculator, here is an explanation of what is actually being calculated:

Heat Transfer Capacity

GPM chiller calculation aims to ensure that the volume of water flow is sufficient to carry the cooling load (TR) from the building back to the chiller. If the GPM is too low, the water will not be able to carry enough heat, the result from this situation is the room is still warm or not cool enough as the owner wishes.

Balance Between Flow Rate and Temperature (GPM = (TR × 24) / ΔT)

This chiller calculation maintains the balance between water flow rate and temperature difference (Delta T) to ensure system efficiency.

Chiller calculation formula

GPM = (TR × 24) / ΔT

Case example

Rory is an HVAC engineer, he is designing a chilled water system for a new medicine warehouse building. The mechanical team has selected a 200-ton chiller (TR) to handle the cooling load. Based on the chiller manufacturer’s specifications in their catalogue and standard design practice, the temperature difference (ΔT) between the chilled water supply and return is expected to be 10°F (supply at 44°F, return at 54°F).

Calculate flow rate (in GPM):

GPM = (TR × 24) / ΔT
GPM = (200 × 24) / 10
GPM = 4800 / 10
GPM = 480

The required chilled water flow rate is 480 GPM. Therefore, the primary chilled water pump and associated piping should be designed for a minimum flow rate of 480 GPM.

Now that you already know how to calculate GPM for chiller, we wonder if you are interested in calculating BTU to PK for air conditioner on this link? Or eager to try our free plugin to automatically draw ductings and their fittings on this link?