Beyond Air Changes Per Hour: Applications of CFD Modeling for Effective and Energy-Efficient Ventilation
The COVID-19 pandemic put a spotlight on building ventilation systems due to increasing awareness of aerosol transmission of respiratory pathogens. To mitigate the spread of SARS-CoV-2, innumerable guidelines and best practices documents recommended enhanced ventilation as measured by the number of air changes per hour achieved for an indoor space. However, simply increasing airflow in its current configuration does not consider the performance of the air distribution system at preventing stagnation zones, and relying on dilution alone is inadequate for contaminants that present a high risk at very low doses. Furthermore, there are significant energy impacts associated with increasing air exchange rates, creating a potential conflict between decarbonization and infection control objectives. Computational fluid dynamics (CFD) modeling is a powerful tool to improve the design of building ventilation systems to reduce the mean age of air in the breathing zone relative to the well-mixed condition. Using CFD we can design systems that reduce infection risk without necessitating exorbitant increases in airflow. This presentation illustrates case studies of CFD applications to increase both ventilation effectiveness and contaminant removal effectiveness at a much lower incremental energy cost than increasing the air exchange rate to achieve comparable performance.
Mr. Mikszewski, PE, CEM is the East Region leader for Resilience & Sustainability at Wood plc with a diverse professional background in environmental engineering and energy management in buildings and facilities. Prior to joining Wood, Alex worked in the public and non-profit sector in NYC helping to implement the One City: Built to Last initiative, whereby NYC committed to reducing its GHG emissions by 80 percent over 2005 levels by 2050. First, he worked on the NYC Agency side as an energy and facilities manager for Brooklyn Public Library and the Metropolitan Museum of Art, and then worked directly for the NYC Division of Energy Management (DEM). At DEM Mr. Mikszewski oversaw the expense-funded building energy retrofit program and NYC’s innovative energy technology demonstration program. During the COVID-19 pandemic, Mr. Mikszewski served on a Ventilation Task Force for NYC public buildings and developed novel risk assessment tools for aerosol transmission of SARS-CoV-2 to inform reopening strategies. He is part of the multidisciplinary, international research project “Making Australia resilient to airborne infection transmission” funded by the Australian Research Council.