Excess Energy Consumption Assessment of Natural Ventilation due to COVID-19 Expansion in a Bank Building

• Ventilation optimization reduced COVID-19 infection risk by up to 38.78%. • Natural ventilation lowered cooling energy consumption by 16.65%. • Electrochromic glass cut cooling demand by 16.7% during peak summer. • Infection risk dropped from 4.5% to 1.51% using electrochromic windows. • NSGA-II algorithm identified trade-offs between energy, infection risk, and occupancy. The COVID-19 pandemic has significantly reshaped the design priorities of indoor environments, emphasizing the need for effective strategies to mitigate airborne transmission while maintaining energy efficiency. This study investigates optimizing of ventilation strategies in a bank building, focusing on the combined use of mechanical systems, natural ventilation, and electrochromic glazing. Various scenarios were simulated under extreme climatic conditions to assess their impact on HVAC energy consumption and infection risk. Ventilation flow rates ranging from 0.25 to 0.45 m³/s were evaluated by ASHRAE and WHO guidelines. The analysis revealed that increased ventilation significantly lowers infection probability, especially at lower occupant densities, but leads to higher energy consumption beyond a certain threshold. Natural ventilation proved effective in reducing both energy use and infection risk, particularly during the hottest week. Moreover, the implementation of electrochromic glass resulted in a 16.7% reduction in cooling energy demand and a substantial decrease in infection risk from 4.5% to 1.51%. The novelty of this research lies in its integrated multi-objective optimization framework using the NSGA-II algorithm, which simultaneously considers infection risk, energy use, and occupant density. Additionally, the study employs a co-simulation approach combining EnergyPlus and MATLAB, and uniquely evaluates the role of electrochromic glazing in enhancing pandemic resilience. The outcomes offer practical insights for designing energy-efficient, health-conscious indoor environments during and beyond pandemic conditions.