Impact of chilled ceiling on indoor air distribution in a room with mixing ventilation

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 buildings. This paper presented an experimental study concerning the effect of CC on the indoor air distribution with MV when the internal and external sensible cooling loads changed. The vertical distributions of indoor air temperature, air velocity and contaminant (CO2) concentration were evaluated by the vertical air temperature difference, turbulence intensity and contaminant removal effectiveness, respectively. The results showed that when chilled ceiling surface temperature ranged from 17.0 °C to 26.0 °C, the average vertical air temperature difference, turbulence intensity and contaminant removal effectiveness were 0.2 °C–0.4 °C, 30%–36% and 0.6–0.84 when both internal and external sensible cooling loads were 41.5 W/m2. Moreover, the ranges of these evaluation indices varied slightly when the internal or external sensible cooling load increased from 41.5 W/m2 to 69.5 W/m2. Hence, the chilled ceiling had a slight impact on the indoor air distribution in a room with mixing ventilation. It is interestingly found that the small vertical air temperature difference coincided with the large turbulence intensity and contaminant removal effectiveness with different internal or external cooling loads.