Working of Cooling Tower on Psychrometric Chart

Your question is pretty broad. Here's an equally broad answer.

Learn to use a psychrometric chart, that will establish the limiting conditions the Cooling tower might be capable of at equilibrium conditions without regard to mass and energy balance and mass transfer limitations.

Learn to do material and energy balances. That will tell you the performance based on the quantity of air and water passed through the unit, assuming equilibrium conditions (ignoring mass transfer limitations).

Learn mass transfer phenomena. That will tell you how close you can expect to get to equilibrium conditions.

Solve all three problems above simultaneously until all conditions are satisfied. You will have your answer.

Failing that, contact you CT supplier who can simulate all of this quite readily.

If you don't like that solution solve it using a chemical process simulation package--though it may require empirical data to solve the mass transfer problem.

Get inputs from the supplier about the cooling tower first. It is atmospheric type or fan assisted type etc etc.

Winter and summer changes are quite big. In winter with air becoming Drier the WBT will go down. In summer and mainly rainy periods the WBT will be very close to ambient temp , so efficiency will be low.

Even in 24 hrs period there are changes in ambient conditions and early morning you have highest RH.

When you need a constant temperature out of cooling tower 24X7x365 days , put a temperature controller in out let water sump and switch on/off the Fan automatically, with the set points fixed , as desired.

Dear Mr. Chakraborthy ranbir,

I want to supplement to your answer - during rainy period the air will be highly saturated and cooling range will come down - which means more air is to be circulated for the same range of cooling (or) for the given quantity of air flow- the cooling range will come down.

Thanks,

rajeswari.d