Currently displacement ventilation(DV) and cooling ceiling (CC) system has two main disadvantages: condensation when the radiant panel temperature is lower than the dew point temperature of air around it

and the downdraft from the cooling ceiling. Through theoretical analyses

the paper puts forward a method to avoid condensation and downdraft: the radiant panel is covered and airproofed with the film whose long wave transmittance is high

and there is a layer of air or vacuum between the undersurface of panel and the film. The experiment system was designedwith long wave transmittance film

and the capability of the new system was validated through the experiment. It is shown that with the same ambient environment

the indoor temperature in DV/CC system with film is 1.8% higher than that in tradition DV/CC system

and the contaminant concentration is 60% decreased under the breathing zone and 40% decreased above the breathing zone

respectively