Thermal performance evaluation of a new type of green roof system

The increase thermal capacity of green roof compared with common roof may lead to bad indoor conditions sometimes. This paper proposes a new type of green roof system with ventilation layer. And the new green roof could lower internal surface temperature in summer and increase internal surface temperature in winter in five typical climate zones of China. And the modelling results show that maximum average temperature reduction of internal surface reaches 0.1℃ on typical summer day, and the maximum average temperature rise of internal surface temperature reaches 0.4℃ on typical winter day. Finally, the thermal performance of green roof system under different substrate depth, leaf area index and initial water content ratio are analyzed in details.