A system including a preheating coil and air washing (directly recalculated spray water) is to be designed to process 10,000 ft^3/min of outdoor air, in barometric pressure of 14.696 psia. Outdoor air is saturated at 30 F enters the preheated, where heat is supplied by steam condensing inside tubes of coil. The air then is passed through the air washer. The air state at the exit of washer is 70 F dry bulbs and 60 percent degree of saturation. Average face velocity of the air through the washer is 500 ft/min and mass transfers coefficient H_d*A_v= 400 (lbm/hr*ft^3). Determine:
a) the dry bulb and thermodynamic wet bulb temperature of air entering the washer
b) the required capacity of preheating coil in btu/hr
c) the necessary contact volume of the air washer in ft^3