Refrigerant at 9°C flows through a direct-expansion cooling coil with a total air-side area of 120m2 . Air enters the coil at 31°C db– temperature and 60% relative humidity, with a mass flow rate of...

Refrigerant at 9°C flows through a direct-expansion cooling coil with a total air-side area of 120m2 . Air enters the coil at 31°C db– temperature and 60% relative humidity, with a mass flow rate of 3.5 kgsí1 . The outside and inside heat transfer coefficients are 0.075 kWmí2 Kí1 and 3 kWmí2 Kí1 respectively. The ratio of the outside to inside heat transfer areas is 16. Show that vapor condensation will occur at the entrance section of the coil. Calculate (i) the cooling capacity, and (ii) the db–temperature and humidity ratio of the air at the exit. Plot the condition line on the psychrometric chart.