Measurement-informed simulation assessment of CO2-aware and thermal-buffer-aware ventilation control in a school classroom

Passive-first operation can reduce avoidable energy use in buildings, but its effectiveness in occupied classrooms depends on interactions among thermal buffering, ventilation, comfort, and indoor air quality. This study presents a measurement-informed simulation assessment of passive-first thermal buffering and constrained ventilation operation in a Finnish school classroom. Indoor temperature, CO 2 concentration, occupancy, airflow, heating demand, cooling demand, fan electricity, and outdoor weather were analysed at 15-min resolution. Measured Building Management System operation was the reference and was compared with three simulated rule-based scenarios (CO 2 -aware, passive-first, and integrated ventilation–thermal control), a parameter-tuned Integrated benchmark on a held-out period, and simulated SAC and TD3 benchmarks under the same boundary conditions and constraints. The measured data showed strongly damped indoor temperature variations relative to outdoor conditions. In simulation, the rule-based scenarios reduced fan electricity from 8.14 to 3.70 kWh/day and operating cost by 30.3–30.4%, while heating demand was also reduced. The simulated SAC and TD3 benchmarks reduced daily fan electricity consumption to 3.05 and 2.77 kWh, respectively, corresponding to operating-cost reductions of 37.7% and 41.6%. Thermal-comfort compliance remained above 95% in all scenarios. The findings show that passive-first classroom operation should be evaluated using component-level energy, cost, comfort, and CO 2 performance indicators together.