In a nuclear power plant the cooling tower system must be run on a closed cycle. That is, the air exiting the tower passes over cooling coils to return it to its initial condition prior to reentering the tower. Air at 20 degrees C and 40% relative humidity enters the tower at a rate of 1.3 x 106 kg/sec. Water enters the tower at 50C and leaves at 25C. The water flow rate is 750,000 kg/sec. Saturated air exists the tower and passes over cooling coils which returns it to 20C and 40% relative humidity. Water at 22C condenses out of the air. Determine:
A) The temperature of air leaving the tower
B) Amount of water evaporating in kg/sec.
C) The heat removed by the cooling coils in kW
We can solve this problem using an energy balance.
Heat removed by cooling coils = Heat dissipated by hot water.
Hot water: at inlet Tw1 = 50 c
at out let Tw2 = 25
Mw = ...
Given a power plant cooling situation, this solution shows how to calculate the temperature of the air leaving the tower, water evaporation rate and heat removed by cooling coils using the principles of the conservation of energy.