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How to calculate EER and COP for chiller?

Step 1

Define the water chiller application. In this instance, a chilled water system is used to keep food manufacturing areas near 40 degrees F. The chiller system is recirculating 40 gallons per minute of water that is chilled by 24 degrees F and using 24.8 kW/hr of electricity to produce the refrigeration. With this information you can calculate chiller efficiency in terms of the energy efficiency ratio, or EER, and the coefficient of performance, or COP, for chillers.

How to Calculate Ton Capacity of Chillers

Step 2

Calculate the chiller capacity in tons of refrigeration. The formula for total heat removed in a chiller installation is h = 500 X q X dt where h = total heat removed in Btu/hr, q is the chilled water flow rate in gpm, and dt is the chilled water’s total temperature differential. Substituting, h = 500 X 40 gpm X 24 deg-F = 480,000 Btu/hr. If 1 Ton of refrigeration equals 12,000 Btu/hr, then the system has a cooling capacity of 40 Tons of refrigeration.

Step 3

Calculate the system efficiency by the air conditioning efficiency formula EER = Btu/hr cooling/watts consumed. Substituting actual values, 480,000 Btu/hr/24.8 kW/hr = 480,000 Btu/hr/24,800 watts/hr = 19.35. This is very high cooling performance compared to the 2010 SEER standards of 13-14 for domestic air conditioning which reflects the higher efficiency of the chilled water strategy. COP would be the EER (19.35) X 0.293 = 5.67.