How much water does your Cooling Tower use?

Multiply your cooling tower water inlet flow rate in gallons/minute by the cooling 'range' (This is the inlet water temperature minus outlet water temperature in degrees F), divide by 1,000 and the result will be very close to the rate at which your cooling tower evaporates water in gallons per minute.

ex: Your cooling tower cools 1,500gpm from 95 degF to 85 degF

Solving: 1,500 x 10 / 1,000 = 15 gpm

Water is also intentionally wasted away as 'bleed' or 'blow down' to maintain adequate water quality.

To account for bleed, determine a 'bleed factor' as follows: 'cycles of concentration divided by cycles of concentration minus 1.'

ex:     For two cycles of concentration, the factor is: 2 / (2-1) = 2

          For three cycles of concentration, the factor is: 3 / (3-1) = 1.5

          etc.

Multiply the 'bleed factor' by the evaporation rate and the result is the rate at which your tower uses water.

The result is startling to most people.

The tower above, for example, uses 20gpm at 4 cycles of concentration.

This would be 9,600gallons of water in 8 hours!

Naturally, the tower evaporates less water on cool days because the 'range' is less but all in all, cooling towers consume a lot of water.

So, what does this mean?

-Employ water treatment practices that allow 'cycles of concentration' to be safely elevated.

-Make sure the water being evaporated isn't being counted as 'sewer water'. This can save a lot on sewer charges.

-Watch out when shutting off water lines to fix lawn sprinklers, leaking valves, etc.. Without make-up, cooling tower basins typically become too low to satisfy the condenser water pump after only a few minutes.

-The big picture...It's not just farmers. All industry needs water. Arid climates cannot support dense populations.