Enter the dry-bulb temperature, outlet temperature, and the change in temperature into the calculator to determine the efficiency of the evaporative cooling.

Evaporative Cooling Efficiency Formula

The following formula is used to calculate the efficiency of an evaporative cooling machine. 

eff = ( DB - OT) / ΔT 
  • Where eff is the efficiency of the cooler
  • DB is the dry-bulb temperature
  • OT is the outlet temperature
  • ΔT  is the total change in temperature from inlet to outet

To calculate the evaporative cooling efficiency, subtract the outlet temperature from the dry bulb temperature, then divide by the total change in temperature.

What is evaporative cooling?

Definition:

Evaporative cooling is a process by which heat is transferred from an object or air through the evaporation of water. When water evaporates, it requires heat in order to do so, as a result, it takes heat away from whatever it was in contact with, which then causes cooling on that object.

How to calculate evaporative cooling efficiency?

Example Problem:

The following example outlines how to calculate the evaporative cooling efficiency of a machine.

First, determine the dry-bulb temperature. In this example, the dry-bulb temperature is measured to be 50F.

Next, determine the outlet temperature. For this machine, the outlet temperature is measured to be 40F.

Next, determine the total change in temperature. Between the inlet and outlet, the total change in temperature is 15F.

Finally, calculate the evaporative cooling efficiency using the formula above:

eff = ( DB – OT) / ΔT 

eff = ( 50 – 40) / 15

eff = .666 = 66.6%