Trade-off between embodied and operational carbon emissions of residential buildings in early design stage

Buildings are responsible for a significant portion of the global energy use and carbon emissions. There is great potential to reduce a building's environmental impact in the early stages of design. Over the past decade, there has been a concerted effort to create energy-efficient and net-zero buildings by reducing operating energy. However, additional materials and new applications are needed to reduce energy demand. This may result in an increase in embodied carbon, which is the carbon emitted during the materials and construction phase. Since there is a trade-off between embodied and operational environmental environment, it is important to consider both in the design process. However, there is a lack of research that addresses this issue. To help with this challenge, a multi-objective optimization model that combines machine learning, building information modelling, and life cycle assessment has been developed. This model can help in making design decisions that balance embodied and operational carbon emissions. An actual building project has been used to verify the model developed. The findings reveal that early design stage has the potential to save 32.5% emissions for mid-rise buildings in hot summer and cold winter climate zone in China. Moreover, window-to-wall ratio and number of floors largely affecting the trade-off between embodied and operational impacts. The findings of this study can provide low-carbon and energy-efficient design solutions for residential buildings in the early stages of design.