Optimising building envelope retrofits under future climates: Integrating passive, active, and renewable strategies

This study aims to enhance building energy efficiency and resilience during retrofitting stages to address future climate change impacts by examining a representative commercial building model across various cities. To this end, comprehensive retrofit parameters for the building envelope, including passive, active, and renewable design elements, were integrated into a simulation-based optimisation framework to minimise building energy use, enhance thermal comfort, and reduce life-cycle costs. The optimisation process revealed the significant influence of varying climate scenarios on building performance and the effectiveness of different retrofit strategies. Results demonstrate that renewable energy generation has the potential to meet cooling, heating, and lighting demands under diverse conditions. Seasonal and temperate climates show potential for retrofitted buildings to meet net-zero energy buildings (NZEB) by 2050, with retrofit costs maintaining comparable to current levels. However, due to global temperature warming, the risk of overheating is anticipated to increase significantly across all cities, from an average of 4.91% under current conditions to 23.98% in future scenarios, posing substantial challenges in managing heat-related stress for occupants. Moreover, by employing the heuristic multi-criteria decision-making (MCDM) framework to identify optimal retrofit solutions for different regions, the findings underscore the limitations of current climate-based design approaches and recommend tailored strategies that consider both interactions between retrofit parameters and local climate conditions to effectively achieve zero-energy targets in the future.