Quantifying the Effects of HVAC Operation to Mitigate Aerosol Concentration in a Classroom using CFD
Thesis - Open Access
Master of Science (MS)
Department / School
Heating, ventilation, and air conditioning (HVAC) is a complex mechanical system for the transition of air between outdoor and indoor areas. These systems are directly responsible for temperature, humidity, and air flow into any given space, thereby providing a level of comfort to those who live indoors. These systems account for 52 percent of U.S. energy consumption. When designing HVAC systems, indoor air quality (IAQ) is the main focus for achieving safe and clean air, such as in the case of airborne diseases. HVAC systems are responsible for the flow of air in indoor spaces and thereby expand the transmissible pathways of any given airborne virus. As a result, engineering and health organizations such as the World Health Organization (WHO), the Centers for Disease Control (CDC), and the American Society of Heating, Refrigeration, and Air conditioning Engineers (ASHRAE) have issued many guidelines. The focus of this study was to scientifically prove these guidelines and to determine whether the blanket statements provided by these organizations are supported by simulation results of various layouts in a university classroom setting. Computational fluid dynamics (CFD) is used as the foundation for software to determine the effects of mitigation strategies on the transmission of infectious aerosols. In this study, a university classroom located on South Dakota State University (SDSU) campus was modeled in computer-aided design (CAD) software and then imported into CFD software with a set of baseline physics conditions that would be used for various mitigation strategy. The mitigation strategies proposed in this study for the same university classroom are as follows: (1) airflow modification, (2) introduction of an acrylic barrier, (3) room layout adjustments, and (4) air redistribution techniques. Results show that the best and worst results are unique and there is no overlap between heating and cooling simulations sets. For instance, a bad result would be an overall increase in aerosols being distributed throughout the breathing zone of the room, whereas a good result would be a decrease in overall aerosols being distributed. Furthermore, there appears to be no one-size-fits-all solution throughout the calendar year, and each room under the influence of an HVAC system will have a unique strategy to mitigate the transmission of infectious aerosols.
Library of Congress Subject Headings
Classrooms -- Heating and ventilation.
Computational fluid dynamics.
Infection -- Prevention.
Number of Pages
South Dakota State University
DePrez, Scott, "Quantifying the Effects of HVAC Operation to Mitigate Aerosol Concentration in a Classroom using CFD" (2023). Electronic Theses and Dissertations. 615.