Near-optimal temperature setpoint transition strategies for peak load reduction and thermal comfort in grid-integrated school buildings

This paper presents a framework for managing peak space-conditioning loads and indoor comfort in grid-interactive buildings using optimized temperature setpoint transition strategies. While the conventional thermostatic night setback approach relies on zone air temperature control for regulating building heating/cooling demand, this study employs a novel sensor technology that provides real-time effective room temperature integrating radiant and convective thermal effects in its measurements. Grey-box thermal models calibrated with this effective temperature, which closely approximates operative temperature, are used to control peak heating loads and rebound effects in a classroom with convective heating system during winter conditions. To unlock building energy flexibility while ensuring indoor thermal comfort during active demand response (DR) events, two rule-based control scenarios are evaluated and compared: a reference case using step-change setpoint curves to control room air temperature, and flexible scenarios using near-optimal setpoint curves to control room operative temperature. Results show that for a single-phase DR event considering morning peak demand only, the flexible scenarios reduced peak heating load by 46% compared to the reference case. For multi-phase DR events including prebound, peak and rebound periods, operative temperature control reduced preheating demand by 42%, fully curtailed on-peak load, and lowered subsequent rebound peaks by approximately 60%. Additionally, the flexible control scenarios achieved considerable energy cost savings under time-of-use and flat-rate pricing while maintaining satisfactory indoor comfort. The findings demonstrate that integrating operative temperature feedback with optimized setpoint transition strategies enhances HVAC responsiveness and grid operation, offering a promising approach for scalable DR participation in grid-connected buildings. • A framework integrating operative temperature control with optimized setpoint transitions reduces peak loads in grid-interactive buildings is presented • Methodology is validated through field demonstration in an all-electric school classroom during cold Québec winter conditions. • Optimized temperature setpoint ramps fully eliminated on-peak heating demand and reduced rebound power by 60% compared to conventional step changes. • Energy cost savings of 86% are achieved under time-of-use pricing without compromising indoor comfort.