This study constructs a system dynamics (SD)-based energy efficiency model for retrofitting existing residential buildings by considering urban residential buildings in Liaoning Province, China. In this study, we sorted the boundaries of building energy efficiency accounting, analyzed the current status of related research and system dynamics theory, determined the influencing factors and transmission mechanisms of residential building energy efficiency renovation, set the research boundaries and assumptions, drew the circuit diagrams of various subsystems, determined the main equations and parameters of the model, and ensured the reliability of the model through stability and historicity tests. Through scenario simulation and analysis, it was found that, from 2016 to 2035, the comprehensive benefits of urban residential building renovation will grow slowly in the early stage and rapidly in the late stage, which will potentially have large benefits. The socio-economic environment, governmental policies, energy-saving technologies, market demand, and other factors influence each other, among which the progress of energy-saving technologies has the greatest impact on the comprehensive benefits. Changing the inputs of a certain aspect cannot make the benefits of energy consumption, environment, and economic tripartite grow equally. The energy consumption benefit potential of centralized heating renovation is larger. The results of this study provide a theoretical basis and decision support for the energy-saving transformation of existing residential buildings.

Facing the goal of “double carbon” in our country, this research focuses on the quantitative benefits of BIM technology in the promotion and application process based on the development needs of green buildings. Through the establishment of green building evaluation index system, the impact of BIM technology on energy saving rate, light benefit and other core indicators is quantitatively analyzed. At the same time, research and construction of BIM based green building design optimization model, which can solve the optimal economic and comfort scheme. This supports scientific decision-making on green building projects. In addition, the paper evaluates the economic benefits of BIM technology application, as well as the technology promotion path of policy and market two-wheel drive. The results show that: 1) BIM technology can significantly improve the economic, social and environmental benefits of green buildings; 2) BIM technology used in green building design optimization is conducive to obtaining positive technical and economic benefits; 3) The evaluation and analysis framework established in this research can provide theoretical reference and empirical support for promoting the deep integration of BIM technology and green buildings in our country.