Adaptive supervisory control for optimizing buildings’ energy flexibility with hybrid HVAC systems under variable climates and operation conditions

Adaptability to various climates is a key part of comprehensive green retrofitting. As Heating, Ventilation, Air Conditioning, and Cooling (HVAC) systems performances are highly climate-dependent, designing control strategies must be evaluated across varied meteorological contexts. This study introduces an adaptable Demand Side Management (DSM) framework to maximize the buildings’ flexibility and maintain thermal comfort. Three case studies, including a single-zone apartment, a multi-zone residential building, and a large nearly zero-energy commercial building, are simulated using validated EnergyPlus models, with model accuracy confirmed using ASHRAE Guideline 14–2002. DSMs are developed using three main control approaches: Optimized Fuzzy Sliding Mode Controller (OFSMC), Model Predictive Control (MPC), and a traditional relay controller. Supervisory optimization is designed based on Genetic Algorithm (GA) to enhance the buildings’ flexibility across relay controller. Long-term simulations (1 year, 10-minute resolution) across eight ASHRAE 169 climate zones show that OFSMC increases the Flexibility Index (FI) by 27.7 % on average in residential buildings and achieves 36.3 % FI improvement in commercial buildings, while maintaining indoor temperatures within the comfort range for up to 90 % of the year. MPC-GA increases residential buildings FI by 30.1 % on average, but its performance in the commercial building is limited based on thermal-comfort infraction under varying climate conditions and uncertain occupants’ schedules. These results highlight that controller performance depends strongly on climate severity, model accuracy, and HVAC system complexity. The study demonstrates that OFSMC provides the most-robust performance in energy flexibility and thermal comfort, under diverse operational conditions, whereas MPC-GA performs best in well-modeled systems with lower uncertainty. • The controllers’ performances are assessed in 8 climate zones and 3 case studies. • The methods’ efficacies are analyzed in energy flexibility & zones temperature. • MPC-GA and OFSMC enhance flexibility by 30.1 % and 19.25 % in residential buildings. • OFSMC boosts flexibility by 27.7 % on average vs. relay control. • OFSMC suits uncertain buildings, while MPC-GA fits precisely modeled buildings.