An integrated approach of building information modelling and life cycle assessment (BIM-LCA) for gas and solar water heating systems

Buildings are responsible for the energetic consumption and potential greenhouse gas emissions during their life cycle. Water heating system contribute to a building's energetic consumption, mainly in residential units, throughout the building's operational phase. Variability in energy sources, reservation and distribution systems of hot water along with the types of construction materials used in these building systems are key decisions to make in the initial design phases of a building project. Often, the definition of the most appropriate water heating system for a building is made via a technical-economic decision. However, the decision is rarely based on natural resource consumption and environmental impact generation throughout the life-cycle of the heating systems and of buildings as a whole. This study presents an application of a specific environmental management tool, based on an integrated Building Information Modelling (BIM) and Life-Cycle Analysis (LCA) method for selection of hot water systems, during the early design building phase. The proposed approach is implemented in the pre-operational phase, in order to enable decision makers to appreciate the resulting environmental performance of water heating systems in buildings. The applicability of the framework is tested via a comparative study of solar heating water systems and natural gas heating water systems for a residential multifamily building to be constructed in Rio de Janeiro, Brazil. For the indicators damage to human health and damage to ecosystem, results indicate that the greatest impact on global warming comes from the natural gas heating system, while for solar heating, free particulate matter was the highest negative contribution. The operation phase for the natural gas system was highest for climate change while for solar heating system, it was the fresh water that was impacted the most during the pre-operational phase of the system's use.