Speaker
Description
Buildings are the backbone of urban development and one of the greatest contributors to global environmental degradation. In rapidly urbanising cities like Kumasi, Ghana, sustainable urban development is urgent. In this regard, the roof, which is most exposed to solar radiation, is a key area of intervention. Among the strategies being adopted globally is the green roof. Green roofs can improve energy efficiency, reduce operational carbon and increase thermal comfort. In Ghana, studies on the thermal performance of buildings with green roofs are lacking. This study fills that gap by using an integrated Building Information Modelling (BIM) and Life Cycle Assessment (LCA) to evaluate the environmental impact of green roofs as compared to concrete roofs. An Experimental Hub at Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, was used as a case study to develop and validate detailed BIM models. Parametric modelling and environmental simulations were done using Rhinoceros 3D, Grasshopper, Ladybug, and Honeybee, and embodied carbon and life cycle inventory data were obtained from the Inventory of Carbon and Energy (ICE) and EcoInvent databases. The analysis focused on embodied carbon emissions, operational energy demand, and thermal performance under local climatic conditions. The study demonstrates reductions in annual cooling loads, lower operational carbon emissions, and improved indoor thermal comfort compared with the concrete roof. The recorded embodied carbon was 1.2 times greater in the concrete roof than in the green roof. Moreover, energy consumption was 1.23 times less in the green roofing system than in the concrete roof. The study offers empirical evidence that can be used in sustainable design practices and in policy-making to reduce the environmental impact of the construction industry in Ghana. In addition, this study demonstrates the usefulness of BIM-LCA integration as a methodological approach to building performance evaluation in developing nations.
Keywords: Building Information Modelling (BIM), Life Cycle Assessment (LCA), Green Roofs, Embodied Carbon, Operational Carbon, Thermal Performance, Ghana.