Optimal control of high-rise building mechanical ventilation system for achieving low risk of COVID-19 transmission and ventilative cooling

As suggested by many guidelines, a high ventilation rate is required to dilute the indoor virus particles and reduce the airborne transmission risk, i.e., dilution ventilation (DV). However, high ventilation rates may result in high energy costs. Ventilative cooling (VC), which requires high ventilation rates like DV, is an option to reduce the cooling energy consumption. By combining DV and VC, this paper investigated the operation of the mechanical ventilation system in high-rise buildings during the COVID-19 pandemic, aiming to minimizing the cooling related energy consumption and reducing COVID-19 transmission. First, a modified Wells-Riley model was proposed to calculate DV rates. The ventilation rate required to achieve VC was also introduced. Then, a new ventilation control strategy was proposed for achieving DV and VC. Finally, a case study was conducted on a real high-rise building, where the required DV rate and the impact of the settings of the mechanical ventilation on the energy savings were evaluated. The results indicate that the required ventilation rates vary from 36 m(3)/s to 3306 m(3)/s depending on the protective measures. When the occupants follow the protective measures, the proper settings of the mechanical ventilation system can reduce energy consumption by around 40%.