An Experimental Study of Indoor Air Distribution Characteristics in a Room with Mixing Ventilation and Chilled Ceiling

Abstract

A mixing ventilation (MV) system integrated with a chilled ceiling (CC) cooling system will be a potential advanced heating, ventilation and air conditioning (HVAC) system in the modern office buildings. In this paper, an experimental study of the air distribution characteristics in a room with MV and CC was performed when considering the effect of the heat transfer of external envelope. The distributions of indoor air temperature and velocity were measured and evaluated by the vertical air temperature difference and turbulence intensity, respectively. The results showed that when chilled ceiling surface temperature ranged from 17.0 to 26.0 °C and supply air temperature was 16.0–22.0 °C, the increased trend of vertical air temperature was gradually switched to the decreased trend along the vertical direction, and the vertical air temperature differences in occupied zone were all not exceeded 0.4 °C. The average turbulence intensity was 30–41% when the internal and external sensible cooling loads equal 41.5 W/m2. The range of these evaluation indices varied clearly when the internal sensible cooling load increased from 41.5 to 69.5 W/m2, whereas they were almost the same when the external sensible cooling load increased from 41.5 to 69.5 W/m2.