Chilled air at 15C enters a horizontal duct at a speed of 1m/s. The duct is made of thin galvanized steel and is not insulated. A 30m section of the duct runs outdoors through humid air at 30C. Condensation of moisture on the outside of the duct is undesirable, but it will occur if the duct wall is at or below the dew point temperature of 20C. For this problem, assume the condensation rates are so slow that their thermal effects can be ignored. Suppose the duct's square cross section is 0.3m by 0.3m and the effective outside heat transfer coefficient is 5W/m2/K in still air. Determine whether condensation occurs