At steady state, a device for heating and humidifying air has 250 ft3/min of air at 40of, 1 atm, and 80% relative humidity entering at one location, 1000 ft3/min of air at 60of, 1 atm, and 80% relative humidity entering at another location, and liquid water injected at 55of. a single moist air stream exits at 85of, 1 atm, and 35% relative humidity. determine:
(a) the rate of heat transfer to the device, in btu/min.
(b) the rate at which liquid water is injected, in lb/min.