The city of La Paz in Bolivia lies at an altitude of 3650m abovesea level. Average atmospheric pressure is 62.3 kPa, averagedaytime temperature is 8.8 oC, and average relative humidity is55%. The power station at La Paz airport uses a Baltimore Aircoil3501A cooling tower; water coming from the condenser coolingcircuit enters the top of the tower at 144 litres/s at 36 oC. Moistair at average ambient conditions enters the bottom of the towerand exits at the top at 12 oC with a relative humidity of 100%. Thechange in air pressure between inlet and outlet is negligible.
(a) If the evaporative cooling process in the tower loses 4% ofthe incoming water stream, what is the temperature of the coldwater leaving the bottom of the tower?
(b) Under these conditions, what is the cooling capacity of thetower in tons? The rated capacity of the tower at normal ambientconditions (i.e. sea level, 21 oC wetbulb) is 500 tons: why is itoperating so far from this point in La Paz?
(c) What is the volume flow rate of dry air leaving thetower?
