Performance evaluation of hybrid green roof system in a subtropical climate using Fluent

Energy disaster is one of the major obstacles in the progress of human society. There are some on-going researches to overcome this for a sustainable environment. Green roof system is one of them which assist to reduce energy consumption of the buildings. The green roof system for a building involves a green roof that is partially or completely covered with vegetation and plant over a waterproofing membrane. Green roofs provide shade and remove heat from the air through evapotranspiration, reducing temperatures of the roof surface and the surrounding air. This paper reports the thermal performance of hybrid green roof system for a hot and humid subtropical climatic zone in Queensland, Australia. A thermal model is developed for the green roof system using ANSYS Fluent. Data were collected from two modelled rooms, one connected with green roof system and other non-green roof system. The rooms were built from two shipping containers and installed at Central Queensland University, Rockhampton, Australia. Impact of air temperature on room cooling performance is assessed in this study. A temperature reduction of 0.95˚C was observed in the room with green roof which will save energy cost in buildings. Only 1.7% variation in temperature was found in numerical result in comparison with experimental result.