Moist air at 45?C and relative humidity 30% (State 1) with another stream of moist air at 20?C and relative humidity 50% (State 2) in an adiabatic duct. Mass flow rate of dry air is 0.8 kg/s at section 1 and 1 kg/s at section 2. The mixed stream (State 3) is cooled until condensation is about to begin (State 4) at the exit. Temperature of the cooling section boundary is maintained at 5?C. Total pressure is 1 atm throughout the system.
a) Show the process for moist air on psychrometric chart. Label states 1 through 4.
b) Calculate temperatures (?C) of the mixed stream at sections 3 and 4 and relative humidity (%) at section 3.
c) Determine the rate of heat transfer (kW) in the cooling section.
d) Find the rate of entropy generation (kW/K) in the cooling section.