For the cooling tower described in Example 19.3, predict the effect of increasing the air rate by 20 percent with the same liquid rate and a wet-bulb temperature of 75°F.

Example 19.3 A counterflow induced-draft cooling tower operates with inlet and exit water temperatures of 105 and 85°F when the air has dry-bulb and wet-bulb temperatures, respectively, of 90 and 76°F. The tower has 4 ft of stacked plastic fill, and the flow rates are G_y = 2,000 lb/h-ft² and G_x = 2.200 lb/h-ft². 

(a) Determine the number of transfer units, the height of a transfer unit based on the overall gas-phase driving force, and the temperature approach. 

(b) If the cooling load remains the same but the air temperature drops to 70°F with a wet-bulb temperature of 60°F. predict the water temperature and the temperature approach.