Heating, ventilation, and air-conditioning (HVAC) systems play a pivotal role in demand response (DR) by enabling load modulation to enhance energy flexibility. However, traditional strategies often optimize only a single variable—such as indoor temperature or chilled water temperature—limiting coordinated system control. In addition, the influence of dynamic occupant distribution on building energy performance and flexibility is rarely considered, especially in high-occupancy spaces like libraries.To address these limitations, this study proposes a multidimensional synergistic control strategy that simultaneously optimizes indoor temperature setpoints, chilled water supply temperature, and fresh air unit operation to enhance energy efficiency and DR performance. A TRNSYS-based simulation model of a university library in Hunan Province was developed to evaluate the strategy. Key performance indicators included peak load reduction, energy savings, and indoor thermal comfort, benchmarked against a baseline control strategy. The impact of occupant seating patterns on control effectiveness was also examined.Results show that, compared to the baseline strategy (ST1), the proposed strategy (ST6) reduces energy consumption during DR periods by 34.3%, daily energy use by 14.92%, and electricity costs by 20.00%. Concentrated occupant distribution further improves load regulation and system efficiency. This study demonstrates that integrating occupant behavior into multidimensional HVAC control offers a scalable and effective solution for enhancing DR capacity, building energy performance, and operational cost savings.
