Cool air enters a classroom at 12.8°C. The cool air is heated by the students in the room, by the lights in the room, and by heat transfer through the classroom walls. The total heat-transfer rate to the air is 22,156 kJ/hr. The air leaves the room at 25.5°C. Determine the following:

A. The air mass flow rate (kg/hr)

B. The air volumetric flow rate (m³/hr) at inlet conditions

C. The duct diameter (m) for an entering air velocity of 3.1 m/s