Assessment of Airborne Disease Transmission Risk and Energy Impact of HVAC Mitigation Strategies

Abstract

The COVID-19 pandemic has focused renewed attention on the ways in which building HVAC systems may be operated to mitigate the risk of airborne disease transmission. The most common suggestion is to increase outdoor-air ventilation rates so as to dilute the concentrations of infectious aerosol particles indoors. Although this strategy does reduce the likelihood of disease spread, it is often much more costly than other strategies that provide equivalent particle removal or deactivation. To address this tradeoff and arrive at practical recommendations, we explain how different mitigation strategies can be expressed in terms of equivalent outdoor air (EOA) to provide a common basis for energy analysis. We then show the effects of each strategy on EOA delivery and energy cost in simulations of realistic buildings in a variety of climates. Key findings are that in-duct filtration is often the most efficient mitigation strategy, while significant risk reduction generally requires increasing total airflow to the system, either through adjusted HVAC setpoints or standalone disinfection devices.

Review of Engineering Controls for Indoor Air Quality: A Systems Design Perspective

“…In response to the COVID-19 pandemic, UVGI has been reviewed and highlighted as one important technology for disinfection [276][277][278][279][280]. Concerning the fact that increasing ventilation rates are not desirable due to high energy impact, UVGI is considered an alternate approach to mitigate the infection risk [281] during the winter season [282] and in crowded spaces in hot/humid climates [283].…”

Ventilation Requirements and Recommendations for Controlling SARS-CoV-2 and Variants Outbreaks in Indoor Gathering Places with Close Contact

“…This control strategy should be considered by putting in the facility management office on disaster management, similar to ensure fire safety management as pointed out to be under facility management [45]. Energy use impact for ventilation in controlling virus transmission through air should be handled properly with further studies [46].…”