Air at 14.7 psia, 55*F, 60 percent relative humidity is first heated to 72*F in a heating section and then humidified by introducing water vapor. The air leaves the humidifying section at 75*F and 65 percent relative humidity. Determine
(a) the amount of steam added to the air, in lbm H2O/lbm dry air.
(b) the amount of heat transfer to the air in the heating section, in Btu/lbm dry air.