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

Abstract

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%.

Energy, economic, and environmental impacts of enhanced ventilation strategies on railway coaches to reduce Covid-19 contagion risks

“…By analysing the obtained results, starting from the no mask case, it is possible to notice that, for a ventilation rate equal to 18 vol/h (RS), an infection probability of 2.38% is achieved, which is above the 1% threshold value considered as a safe one, as also specified in literature [ 22 ]. By rising the ACH to 31 vol/h (PS2 and PS2.1), an infection probability reduction equal to ∼ 40% vs. RS is detected.…”

“…The role of mechanical ventilation is investigated also in Ref. [ 22 ] where the authors study a high rise institutional building located in Montreal. The analysis focuses on the assessment of the optimal outdoor airflow rate guaranteeing a Covid-19 contagion risk below 1% (assumed as a safe threshold), at the variation of quanta emission rate.…”

Dynamics of SARS-CoV-2 spreading under the influence of environmental factors and strategies to tackle the pandemic: A systematic review

“…Higher ventilation is suggested to reduce the risk of airborne infection, also known as dilution ventilation ( Qian et al, 2020 ). However, high ventilation also increases energy consumption and operating cost Sha et al (2021) . suggested ventilative cooling and dilution ventilation that could reduce energy consumption in high-rise buildings and, thus, reduce the risk of virus transmission Henriques et al (2021) .…”

Nationwide assessment of energy costs and policies to limit airborne infection risks in U.S. schools

“…Several recent studies have explored the energy consumption of HVAC systems in different buildings when maintaining a low risk of COVID-19 transmission. For instance, Sha et al [ 43 ] investigated the relationship between increased ventilation rate and energy consumption in high-rise buildings, and found a ventilation rate of 5.2 ACH is required to maintain infection risk under 1% when conducting social distance and wearing masks for 8-h exposure, leading to energy consumption of 265 MWh for chiller system, and 252 MWh for fans. Wang et al [ 44 ] found that the standard minimum airflow rate is insufficient to maintain the infection risk at low level, and the energy consumption can reach up to 2.9 kWh for 1-h exposure when limiting the infection risk below 2%.…”