Economic Evaluation and Sustainable Optimisation of Envelope Parameters of Building Energy-Efficiency Design Standards in Cold Regions: A Case Study of Shijiazhuang, China

To address the global environmental crisis and achieve sustainable development in the construction industry, the thermal-engineering requirements for building envelope structures in China have been increasing year by year. However, the contradiction between the long-term environmental benefits brought by high-level energy-saving standards and the short-term initial-investment increment has become increasingly prominent. Based on the marginal benefit theory and multi-objective optimisation algorithm, this study constructed a sustainable optimisation framework for the envelope parameters of building energy-saving design standards in cold regions of China. Taking residential buildings and public buildings in the typical city of Shijiazhuang as examples, the optimal marginal benefit values of the thermal parameters of the building envelope were obtained, as well as a multi-objective-optimisation optimal solution that comprehensively weighs the three-dimensional goals of energy efficiency, life-cycle cost, and thermal comfort. This sustainable optimisation framework can provide a scientific and quantified decision-making basis for relevant stakeholders, such as government departments, builders, or architects.