A nationwide assessment of energy flexibility from predictive-controlled heat pump and active thermal energy storage system for building electrification

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.