The impact of thermal loads on indoor air flow

The potential for draught discomfort and high air velocities in the occupied zone are often studied with only cooling design in mind. During the transition season, however, downward flows with high air velocities may occur in the occupied zone due to cold window surfaces. Airflow generated by supply air terminal dervices may further enhence the velocity in the occupied zone. Furthermore, convection flows caused by thermal loads may significantly affect the air flow conditions in the room as a whole and assist the occurance of high velocity near occupants. Analyses of results from full-scale measurements with chilled beams presented in this paper reveal that installations with possibilities of convection flow oposing the supplied flow should be avoided. Generally speaking, convection flows have less impact on air distribution in rooms with chilled beams installed in lengthwise direction than when installed crosswise in rooms.