Abstract：

 In order to explicit the cooling effect of mist spray on the inflatable membrane roof in hot-humid areas adequately, an ethylene tetra-fluoro-ethylene (ETFE) cushion roof in Guangzhou Infinity Plaza is selected as the research object. The cooling effects of this technology on the roof surface and the indoor air are quantified by a field experiment under typical climate conditions in summer, the heat flux variations through the interior and exterior roof surfaces are analysed, and a prediction model for assessing the cooling effect of roof exterior surface is established with meteorological parameters as independent variables. The results indicate that the temperature drops of the exterior and interior surfaces generated by spray system are 3.8-12.3 ℃ and 1.5-2.9 ℃, respectively. The roof mist spray can significantly improve indoor thermal comfort, the average drops of the indoor air temperature and mean radiant temperature are 0.2-0.3 ℃ and 0.2-1.0 ℃, respectively. This technique can also reduce the heat flux entering the room by 21.3% and 33.9% in the morning and afternoon, respectively, which has a positive effect on reducing the building cooling load. Besides, the roof cooling effect is most affected by solar radiation, followed by wind speed, and lastly the wet-bulb temperature. This technique can not only be applied to hot-humid areas, but also can generate good cooling effect in other areas with strong radiation.