Results of laboratory measurements on the thermal performance of the floor-supply displacement ventilation system in comparison with a displacement ventilation system with sidewall mounted diffuser and a ceiling based distribution system are described. The experiments were performed in a controlled chamber configured to resemble a modern office space with modular workstation furniture and partitions. In addition to detailed measurements of temperature, air velocity, and tracer gas concentration, a skin temperature controlled thermal manikin was used to evaluate the non-uniformity of thermal environments produced by these systems. Thermal stratification was observed in both of the displacement ventilation systems which produced greater air temperature differences than the ceiling based system. Under the conditions of the appropriate supply air volume against indoor heat load the displacement ventilation systems could be operated to maintain acceptable thermal comfort and high ventilation efficiency in the occupant zone of the space, at the same time taking advantage of the temperature stratification to achieve energy savings in air conditioning.
