Q4 It is planned to cool water from 110 F to 85 F in a packed counter-current water-cooling tower using entering air at 85 F with a wet bulb temperature of 75 F. The water flow is 2000 lbm/h ft 2 and the airflow is 1400 lbm/h ft 2 . The overall mass-transfer coefficient is KGa=6.9 lb/mol/h ft 3 atm. Calculate the minimum air rate that can be used. Calculate the tower height needed if the air flow of 1400 lbm/h ft 2 is used.

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