Refrigerant flowing through a direct-expansion cooling coil enters at 8°C with a quality of 0.25. Moist air flowing in the opposite direction enters the coil at 30°C, db–temperature and 21°C wb–...

Refrigerant flowing through a direct-expansion cooling coil enters at 8°C with a quality of 0.25. Moist air flowing in the opposite direction enters the coil at 30°C, db–temperature and 21°C wb– temperature. The mass flow rates of refrigerant and air are 2.6 kgsí1 and 3 kgsí1 respectively. The outside and inside heat transfer coefficients are 0.06 kWmí2 Kí1 and 2 kWmí2 Kí1 respectively. The ratio of the outside to inside heat transfer areas is 15. The latent heat of vaporization of the refrigerant is 198 kJkgí1 . The air enthalpy at the exit of the coil is 32 kJkgí1 . Calculate (i) the outside area of the coil, (ii) temperature and humidity ratio of air at the exit, (iii) the quality of the refrigerant leaving the coil, and (iv) the cooling capacity of the coil. Plot the condition line of the air on the psychrometric chart.