Theoretically, the water loss rate should be equal to the water flow rate of the water make-up tank, which can be represented by the overall mass balance of water, L_(make-up) +G_inlet (H_inlet)=G_outlet (H_outlet) (1) where L_(make-up) is the mass flow rate of water from the make-up tank, G_inlet is the mass flow rate of air at the inlet , H_inlet is the humidity of the air at its inlet, G_outlet is the mass flow rate of air at the outlet, and H_outlet is the humidity of the air at its outlet. The amount of makeup water needed by the system can be calculated by determining the water loss due to evaporation. Using a mass balance of airflow in the tower, the mass flow rate of water loss, L_loss, can be represented by, L_loss=G_outlet-G_inlet (2) The mass flow rate of air at the inlet and at the exit of the cooling tower. can be calculated