Creating an efficient ward environment is crucial for the sustainable development of healthcare buildings. This study proposes a methodological framework integrating a phase change material-based thermal energy storage outdoor air system (PCM-TES-OAS) to enable personalized ward environments, aiming to enhance patient comfort and respiratory health with low energy consumption. Four representative cities from different building climate zones in China, namely Beijing, Shenyang, Chengdu, and Shenzhen, were selected for a conceptual case study. The proposed system was theoretically evaluated against a conventional fan coil unit (FCU) plus dedicated OAS (FCU + DOAS) for its summer operational performance, indoor air quality impact, and energy-saving potential. The results indicate that the PCM-TES system remains operational for over 60 % of the time across all four cities. Moreover, the new system achieves an air change rate (ACH) of 8 h⁻¹ to 10 h⁻¹ while maintaining ward CO₂ concentrations consistently at a low level (below 500 ppm). In terms of energy performance, the total summer electricity savings are estimated to be no less than 60 kWh/m² in all evaluated cities. These theoretical findings demonstrate the system’s conceptual potential to simultaneously improve patient comfort, enhance inhaled air quality, and reduce energy consumption in ward environmental control. Additionally, it is recommended that the maximum cooling capacity of the OAS and FCU in the new system be approximately 3 times and 0.3 times that of the conventional system, respectively. This study is anticipated to offer a conceptual framework and a promising new approach to designing comfortable, healthy, and sustainable ward environments.