Cooling Tower Make-up Water Flow Rate Calculation |
To calculate the make-up water flow rate, determine the evaporation rate using one of the following:
1. The evaporation rate is approximately 2 GPM per 1 million BTU/Hr of heat rejection.
2. The evaporation rate is approximately 3 GPM per 100 tons of refrigeration.
3. Evaporation Rate (GPM) = Water Flow Rate (GPM) x Range (°F) x 0.001.
Multiply the evaporation rate by the appropriate correction factor in the table below to calculate the make-up water flow rate, in GPM.
Cycles of Concentration |
Correction Factor |
2 |
2.00 |
3 |
1.50 |
4 |
1.33 |
5 |
1.25 |
6 |
1.20 |
7 |
1.17 |
8 |
1.14 |
9 |
1.13 |
10 |
1.11 |