TY - JOUR
T1 - Outdoor thermal performance of green roofs across multiple time scales
T2 - A case study in subtropical China
AU - Zheng, Xiandi
AU - Kong, Fanhua
AU - Yin, Haiwei
AU - Middel, Ariane
AU - Liu, Hongqing
AU - Wang, Ding
AU - Sun, Tao
AU - Lensky, Itamar
N1 - Funding Information:
This research was supported by the National Key R&D Program of China (No. 2017YFE0196000 ), and the National Natural Science Foundation of China (Nos. 51878328 and 31670470 ).
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/7
Y1 - 2021/7
N2 - In recent years, roof greening technologies have been developed and implemented worldwide, as green roofs are an effective nature-based solution for alleviating outdoor heat and reducing building energy costs. While most observational green roof studies have investigated the cooling effect of model or test plots, few studies have conducted full-scale measurements; however, to guide green roof implementation, the thermal performance of full-scale roofs is crucial. This experimental study explored the ability of extensive green roofs to reduce outdoor temperatures on multiple time scales. The outdoor cooling effect of green roofs and the main factors that drive its performance were analyzed using long-term observational data collected from May 2016 to April 2019 in Nanjing, China. The results suggest that the cooling effect of green roofs exhibits significant diurnal, seasonal, annual, and vertical trends, and that the cooling performance across different time scales corresponds to weather and soil characteristics. The best cooling effect occurred at a height of 60 cm. The green roof displayed a temporary diurnal warming effect but had a good cooling effect on a seasonal time scale, with the largest amount of cooling occurring during the summer (average of 0.28 °C). The findings of this study can support the development, management, and maintenance of green roofs in subtropical areas.
AB - In recent years, roof greening technologies have been developed and implemented worldwide, as green roofs are an effective nature-based solution for alleviating outdoor heat and reducing building energy costs. While most observational green roof studies have investigated the cooling effect of model or test plots, few studies have conducted full-scale measurements; however, to guide green roof implementation, the thermal performance of full-scale roofs is crucial. This experimental study explored the ability of extensive green roofs to reduce outdoor temperatures on multiple time scales. The outdoor cooling effect of green roofs and the main factors that drive its performance were analyzed using long-term observational data collected from May 2016 to April 2019 in Nanjing, China. The results suggest that the cooling effect of green roofs exhibits significant diurnal, seasonal, annual, and vertical trends, and that the cooling performance across different time scales corresponds to weather and soil characteristics. The best cooling effect occurred at a height of 60 cm. The green roof displayed a temporary diurnal warming effect but had a good cooling effect on a seasonal time scale, with the largest amount of cooling occurring during the summer (average of 0.28 °C). The findings of this study can support the development, management, and maintenance of green roofs in subtropical areas.
KW - Extensive green roof
KW - Influencing factors
KW - Multiple time scales
KW - Outdoor thermal performance
KW - Subtropical monsoon climate
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U2 - 10.1016/j.scs.2021.102909
DO - 10.1016/j.scs.2021.102909
M3 - Article
AN - SCOPUS:85103767754
SN - 2210-6707
VL - 70
JO - Sustainable Cities and Society
JF - Sustainable Cities and Society
M1 - 102909
ER -