Enhancing energy efficiency and thermal comfort in residential towers through multi-objective optimization and energy hub systems

Existing high-rise residential buildings often exhibit high energy consumption and inadequate thermal comfort, while building retrofit decisions are rarely coordinated with subsequent district-scale energy-system operation. This study develops a two-stage framework that links building retrofit optimization with multi-energy hub scheduling. First, a validated EnergyPlus model of a residential unit in a 17-story tower is coupled with NSGA-II to optimize insulation, glazing, external shading, and heating and cooling setpoints with simultaneous consideration of energy use and thermal comfort. The model is validated against three years of measured electricity and natural-gas consumption, with deviations of − 6.18%, − 2.87%, and + 1.49% for 2022–2024, respectively. The selected retrofit solution reduces annual energy consumption from 33,336.28 kWh to 28,384.04 kWh (14.85%) and decreases the average predicted percentage dissatisfied (PPD) from 29.51 to 18.69%. Second, the optimized demand profile is scaled to 816 residential units and integrated into a MILP-based energy hub incorporating CCHP generation, renewable energy, electrical and thermal storage, and demand response. Relative to the baseline, storage reduces operating cost by 12.14%, while storage combined with demand response achieves a 19.90% reduction. The results demonstrate that coordinating long-term retrofit decisions with short-term multi-energy scheduling can simultaneously improve building efficiency, thermal comfort, and district-scale operational flexibility.