Effect of ceiling surface temperature on indoor air distribution in a simulated office room with underfloor air distribution and chilled ceiling

This paper presents an experimental study concerning the effect of ceiling surface temperature on the air distribution in a simulated office room with underfloor air distribution at different room cooling loads. The distributions of indoor air temperature, air velocity and pollutant concentration are measured and evaluated by the vertical air temperature difference, turbulence intensity and contaminant removal effectiveness, respectively. The results show that there is a positive temperature gradient below 1.3m as well as a negative temperature gradient above 1.3m when the ceiling surface temperatures vary from 17℃ to 26℃, and the average vertical air temperature difference decreases with the ceiling surface temperature. In addition, the ceiling surface temperature has a slight impact on the distributions of vertical air velocity and contaminant concentration; the average turbulence intensity is from 31% and 43% while the contaminant removal effectiveness is between 0.85 and 1.17.