Developing a multi-objective optimization model for improving building's environmental performance over the whole design process

This study is built upon two previous articles which focus on identifying the key design variables affecting the life-cycle environmental impacts in each design stage of the building design process. This research aims to investigate the trade-offs between embodied and operational impacts and explore potential reduction in the total environmental impacts of a building by varying the identified design variables in each stage of the design process. A multi-objective optimization model based on BIM and LCA integration has been developed to find out the design solution with the optimal trade-offs between the embodied and operational impacts and the option with the minimal environmental impacts. Applying the proposed model to a mid-rise residential building, the results showed that the design process has the potential to lower the environmental impacts of the building by approximately 47.6 %. Moreover, the potential for reducing carbon emissions is greater in the early design stages, with the potential to lower emissions by up to 32.5 %, compared to the lower emission reduction potential of approximately 7.5 % in the detailed and construction design stages. Furthermore, solutions aimed at addressing the trade-off between embodied and operational impacts were identified in each design stage. The study provides an insight into the understanding of how building design can be optimized to mitigate envi-ronmental impacts.