Temperature efficiency , air change efficiency and ventilation efficiency in an office room with displacement ventilation.

A field study of temperature efficiency, air change efficiency and ventilation efficiency in an office room with a displacement ventilation system has been made. The air change efficiency and the ventilation efficiency have been determined by using a tracer gas (N₂0) technique.  Concentrations have been measured at four heights in the room and in the supply and exhaust air. Air temperatures at different positions and heights, air supply temperature, air exhaust temperature, outdoor air temperature, insolation, surface temperatures and air velocities at different positions in the room have been measured. Temperature efficiency was dependent on the supply air temperature. The air change efficiency was very much influenced by the balance between supply air flow rate and the exhaust air flow rate. Values for the ventilation efficiency in the breathing zone were almost equal to those for a dilution ventilation system.