Simulation of humidity and temperature distribution in green roof with pozzolana as drainage layer: Influence of outdoor seasonal weather conditions and internal ceiling temperature
Mostafa Kazemi, Luc Courard
Abstract
The outdoor seasonal weather conditions can influence the insulation performance of extensive green roof. In addition, the thermal behavior of extensive green roof can be affected by the thickness of its layers including substrate and drainage layer. On the other hand, the replacement of polyethylene modular panel with porous aggregates as drainage layer can affect the water retention capacity of green roof. Therefore, in this study, the green roofs with pozzolana (porous volcanic gravel) as drainage layer under constant and variable inside temperatures were modeled and subjected to the weather conditions of winter and summer to assess the humidity and temperature variations in the depth of the systems. The results showed that there was a decrease in temperature through the depth of the green roof system for the winter period, while the reverse occurred for the relative humidity. During the winter period, the green roof model with the 10-cm substrate and 8-cm pozzolana was recommended to be used. However, the model with the 8-cm substrate and 6-cm drainage layer had the best insulation performance, particularly for the summer period. Moreover, the internal ceiling temperature fluctuation of system under variable inside temperature was higher than that under constant inside temperature.