Abstract
Green roofs are becoming a common application in order to improve building energy performance, runoff water control with several additional environmental benefits. Models are essential in the building science due to a necessity of prediction how different structures perform. This knowledge helps to choose right materials and material dimensions. A green roof structure is a complex system of different layers, including growing media and plants. Those two layers make the green roof modelling entirely different from ordinary modelling. Nowadays, several green roof models cover different phenomena and use different physical principles. However, a green roof model is still can be improved. Therefore, this study develops a green roof model- HAMFit-GR that better covers heat and moisture movement sources. The model is based on Heat-Air-Moisture model called HAMFit and Fast All-Season Soil Strength models from US Army Corps of engineers. A combined model is proposed to be more accurate than the most comprehensive green roof models. The result is achieved by adding uncovered components, such as coupling heat and moisture transport in growing media and runoff water flow. Green roof parameters that are required for accurate modelling are measured through laboratory and field experiments. The benchmark data is obtained from the field experiment that is being performed at Whole Building Performance Research Laboratory (WBPRL) of Building Science Centre of Excellence at British Columbia Institute of Technology (BCIT), Burnaby. A case study is prepared with the validated model. The case study includes analysis of green roof parameters impact on roof hydrothermal performance.