A counterflow cooling tower with 30 in. of cellular fill was designed for an approach of 10°F and a cooling range of 17°F when the wet-bulb temperature is 75F. The tower cross section is 36 x 36 ft, and the airflow and water flow rates are 523,000 cfm (at 90°F) and 6,000 gpm. 

(a) What are the inlet air enthalpy and the change in enthalpy across the tower? 

(b) Calculate N_oy and H_oy for these conditions. 

(c) How much more fill would be needed if the wet-bulb temperature were 78°F and the desired approach were 7°F?