Abstract As significant electricity consumers, buildings offer a notable potential for demand-side flexibility through advanced heating, ventilation, and air conditioning (HVAC) systems. A heat pump (HP), critical for building electrification and decarbonization, combined with active Thermal Energy Storage (aTES), especially using Phase Change Materials (PCM), can effectively shift electrical loads to alleviate grid stress during peak demand periods. This study evaluated an integrated HP-aTES system controlled by economic model predictive control (eMPC) via simulations using a Spawn of EnergyPlus framework across diverse climates in the United States (i.e., Atlanta, GA, Buffalo, NY, New York City, NY, and Tucson, AZ), aiming to minimize operating costs through load shifting while ensuring occupant thermal comfort. The studied HP-aTES system utilized a commercial-off-the-shelf water-to-air heat pump in parallel with a PCM-based thermal storage tank to explore their synergistic effects on cost savings, energy flexibility, and grid responsiveness through advanced controls in cooling applications. The simulation results demonstrated the HP-aTES system’s considerable potential, consistently maintaining comfort while achieving significant peak load shifting, exceeding 80% in climates such as Atlanta, GA, Buffalo, NY, and New York City, NY, with prediction horizons of 9–12 hours, and up to 70% in Tucson, AZ. Operating cost savings were highly dependent on utility tariffs, exceeding 40% in high-incentive regions such as New York City, NY, and Atlanta, GA, but remained around 12% under flat rates like those in Tucson, AZ. This was primarily achieved through load shifting rather than an absolute reduction in energy. Furthermore, this study confirms eMPC’s effectiveness for unlocking energy flexibility, emphasizing the crucial role of a sufficient controller prediction horizon and tariff design, and establishes a virtual testbed for future research into sensing, simplified controls, and validation.

Abstract Current research on air-conditioning system flexibility primarily evaluates the peak-shaving effect of individual strategies, lacking a comprehensive quantitative comparison of the benefits and costs of multi-strategy coordination. This paper proposes an integrated evaluation method for multiple flexible regulation strategies that incorporates the rebound effect as a demand response cost. Using an office building as a case study, the comprehensive performance of three standalone strategies (temperature adjustment, supply water temperature adjustment, and precooling) and their combinations under three typical response durations is compared. The results demonstrate distinct scenario applicability of the three strategies due to their inherent characteristics in regulation capacity, rebound costs, and timeliness. In the 60-minute demand response scenario, the indoor temperature increase strategy offers the strongest peak shaving (approximately 60%), but with a high load rebound rate of up to 85%, making it better suited for subsidy-driven demand response programs. The precool strategy provides moderate peak shaving (approximately 10%). Its key advantage is an extremely low rebound (approximately 0.4%), preserving arbitrage potential under time-of-use pricing and making it better suited to price-driven demand response programs. Featuring moderate rebound and minimal occupant impact, water supply temperature increase can improve system COP to achieve energy savings, making it ideal for efficiency-focused demand response. The integrated strategy does not significantly enhance overall performance, demonstrating equivalent peak shaving capacity to individual strategies but with more pronounced rebound. This study provides quantitative support and strategy optimization methods for flexible regulation of air conditioning loads in high-temperature regions.