Integration of a green envelope model in a transient building simulation program and experimental comparison

Green roofs and green walls have several benefits on buildings and cities. They are most often used for water management and for the aesthetical value they provide to the urban environment. These green coatings have a positive impact on the sustainability of building materials. They can improve building energy performance and reduce the amplitude of diurnal variations of the surfaces temperature in summer. The energy saving or comfort improvement is more obvious for hot climates. This paper presents a green envelope model integrated in a transient building simulation program (TRNSYS). This software integration allows dynamic thermal simulations of multizone buildings with green roofs or green walls. The reliability of the model is tested through comparisons to measurements performed on a reduced scale model of buildings during summer period. The impact of the vegetated envelope on cooling energy demand is modeled for various climates.