Currently, outpatient areas in hospital buildings daily accommodate a significant number of patients with various diseases, presenting a dual challenge of augmenting architectural energy efficiency while concurrently elevating levels of indoor comfort. This research introduces a novel approach to enhancing hospital optimal design: by incorporating Phase Change Materials (PCM) within the architectural walls and using automated machine learning to integrate multi-objective optimization for developing PCM wall system strategies under a comprehensive criteria framework. The findings demonstrate that the incorporation of PCM into the walls of buildings markedly improves indoor comfort while simultaneously reducing the demand for energy. However, these benefits come at the cost of certain financial efficiencies. Specifically, after achieving the targeted optimal thermal comfort, the extent of thermal comfort enhancement across various patient groups ranged from 37.0% to 43.5%. Concurrently, energy efficiency improvements were observed to range between 7.64% and 7.98%. The Life Cycle Cost (LCC) of these optimization strategies falls within a range of 44,950 to 83,894 CNY. In summary, these findings underscore the potential of using PCM within the building wall system to advance thermal comfort management and energy conservation design.