Cooling effects of a mist-spraying system on ethylene tetrafluoroethylene cushion roofs in hot-humid areas: A case study in Guangzhou, China

作者：Mao, Huijun; Meng, Qinglin; Li, Shan; Qi, Qianlong; Wang, Shixiao; Wang, Junsong^*

来源：Sustainable Cities and Society, 2021, 74: 103211.

DOI：10.1016/j.scs.2021.103211

• ETFE cushion roof
• Roof spraying
• Cooling and shading effect

Ethylene tetrafluoroethylene (ETFE) cushion roofs are used for improving indoor natural lighting. However, their poor thermal insulation compromises the indoor thermal environment. Water spraying offers promising potential in roof cooling, but its cooling and shading effects on ETFE cushion roofs have not been examined. This paper on roof-mount spraying systems aimed to address this gap with numerical simulation and a full-scale field experiment. Our findings indicated that exterior surface temperatures of ETFE cushion roofs should be kept below 33.7 degrees C to establish a thermally tolerable indoor environment. Secondly, under limitations of field conditions, decreases in exterior and interior surface temperatures yielded by the spraying system respectively ranged from 4.8 degrees C to 19.5 degrees C and from 0.2 degrees C to 4.9 degrees C. Thirdly, the shading effects generated by spraying have been insignificant, with the average solar radiation shading rate being only 0.23. Lastly, decreases in temperatures for both exterior and interior roof surfaces could be expressed as a function of only four parameters with good accuracy (R2 = 0.93 and 0.87, respectively). Decreases in exterior surface temperatures were most affected by exterior surface temperatures, followed by solar radiation, wind speed, and lastly the wet-bulb temperature, whereas decreases in interior surface temperatures were most affected by solar radiation.