Center for the Built Environment

Measurements were made of the thermal performance of a floor-based, occupant-controlled ventilation system. The experiments were performed in a controlled environment chamber configured to resemble an interior zone of a modern office building with modular workstation furniture and partitions. Velocity and temperature distributions were measured at six heights throughout the test chamber for each test configuration. Tests were conducted to investigate the effects of supply volume, supply location, supply direction, supply/return temperature difference, heat load density, and workstation size and layout. Temperature differences in the range of 1 °C to 2.5°C between adjacent workstations were observed, and stratification in the room was strongly dependent on the supply air volume. The jet flow characteristics of the floor supply outlets produced high velocities in their immediate vicinity, increasing the risk of draft discomfort in these regions. However, by controlling the volume and trajectory of the supply air entering the space, office workers were able to control their local environment over a wide range, giving them the opportunity to fine-tune the thermal conditions in their workstation to their personal comfort preferences.