Multi-objective context-aware deep reinforcement learning for energy flexible control of a large multizone office building under extreme heatwave conditions

The increasing frequency and severity of climate-driven heatwaves intensifies cooling demand in buildings, exacerbating peak electricity loads and threatening grid stability. Large multizone office buildings pose challenges with complex thermal dynamics, delayed HVAC responses and strict thermal comfort requirements. Reinforcement learning has shown promise for building energy management, but existing studies focus on nominal weather conditions, small scale buildings, dual-objective optimization and instantaneous state representations, limiting their performance under extreme heat events. To address these gaps, this research proposes a context-aware deep reinforcement learning (DRL) framework based on Soft Actor-Critic to enhance energy flexibility in large multizone office building during heatwaves. The approach includes historical HVAC actions and zone temperatures to capture delayed thermal responses with instantaneous states. It also leverages exogenous weather and electricity price forecasts and dynamic occupancy context. A tri-objective optimization minimizes cooling energy cost, occupant discomfort and peak power demand. Photovoltaic and thermal energy storage are accommodated to support load shifting and grid-responsive operation. The framework is evaluated using EnergyPlus-Python co-simulation with real weather and electricity market data during the 2023 Cerberus heatwave in Italy. Compared to rule-based control, it achieves a 76.55% mean reduction in occupant discomfort, 17.15% reduction in energy costs, 16.45% reduction in total energy consumption and 15.28% reduction in peak power demand. Energy flexibility metrics indicate load shifting index of 20.55% and self-consumption ratio of 95.46%. These results demonstrate the potential of context-aware DRL as a robust and scalable strategy for grid-responsive buildings under increasingly frequent and severe heatwaves.