Green roof set-up analysis: Monitoring and simulation of water and thermal transfer using HYDRUS-1D

Abstract : Urban climate is becoming a real challenge for city planners and one of its main concerns is the Urban Heat Island (UHI) phenomenon. The need to improve inhabitants comfort leads to cooling buildings which can have an impact on UHI and on the energy requirements of buildings. Cooling is attributed to the combined effect of evapotranspiration from soil and plants, shading by vegetation canopy, and thermal insulation by the substrate-drainage layers of the green-roof system (Jim and Peng, 2012). Vegetation can be considered as a renewable heat sink for cooling purposes. Because green roof (GR) is part of the building envelope, its capacity to dissipate energy through evapotranspiration can be a solution especially during summer season and heat waves. The assessment of the evapotranspiration (ET) rate due to GRs is important for the evaluation of the latent heat flux, part of the surface energy balance that influences the urban microclimate. The type of building, but also the vegetation species used, and the growing media are important factors to determine.