Numerical analysis on mechanical ventilation impact on indoor air quality in a basement

Abstract

Indoor air quality (IAQ) in confined spaces like bank vaults and basements is influenced by complex factors such as building layout and HVAC systems. This study examines how mechanical ventilation impacts IAQ in a bank building's occupied basement vault, addressing significant challenges posed by pollutant exposure in these air-tight environments. This study advances safe IAQ in confined spaces, crucial for occupant health and safety, using CFD (ANSYS Fluent Workbench 16.0) and CONTAM 3.2 software for multi-zone ventilation and air quality analysis. It analysed three indoor pollutants: Radon (Rn), Carbon dioxide (CO2), and Particulate Matter (PM2.5), enhancing the reliability and applicability of the findings. The findings indicated that the simulated indoor pollutants concentrations did not exceed the indoor air quality guideline levels. The CFD simulations predicted average steady-state values of 27.2 Bq/m3 for Radon, 574.80 ppm for CO2, and 69.36 µg/m3 for PM2.5 in the basement. For different outdoor air floor rates, an optimal ventilation rate of 4.7 ACH and a cooling load of 17 kW were determined to maintain Radon concentrations below 15 Bq/m3. This provides a practical and actionable solution for maintaining safe IAQ in confined spaces, which is a significant step forward compared to similar studies. These results align with other experimental research, validating the use of numerical techniques in indoor air quality studies. By optimizing HVAC systems to maintain IAQ and minimize energy consumption, the study supports SDG 7 (Affordable and Clean Energy) by enhancing energy efficiency, SDG 3 (Good Health and Well-being) by reducing exposure to indoor pollutants, and SDG 11 (Sustainable Cities and Communities) by improving air quality management in confined spaces. The findings are particularly relevant for Africa, offering practical solutions, informing policy direction, and supporting the African Union's Agenda 2063 and SDGs 3, 7, and 11.