AIR AGE – EVALUATION METHODS

AIR AGE – EVALUATION METHODS

Paper in proceedings outside WoS and Scopus

The article discusses the utilization of controlled ventilation and Computational Fluid Dynamics (CFD) tools to optimize Indoor Air Quality (IAQ) and eliminate contaminants.Given the high uncertainty in boundary conditions during detailed modeling of contaminant spread (e.g., infectious disease transmission), it is recommended to focus on a simplified assessment of ventilation effectiveness using Age of Air (AoA) and Air Change Effectiveness (ACE).The work highlights critical pitfalls in the validation of CFD simulations and the experimental measurement of AoA, such as CFD Limitations, Experimental Inaccuracies, Influence of Geometry, and Measurement Methods.CFD Limitations: Commercial software shows issues with modeling more complex geometry (e.g., in the area of diffusers/outlets) and setting up the computational mesh, primarily failure to meet the y^+ criterion. This fundamentally affects the accuracy of the resulting velocity field and AoA.Experimental Inaccuracies: The measurement of tracer gas concentration (CO2) is burdened by high sensor error (on the order of tens of ppm), calibration problems, and the sensitivity of sensors to direct airflow.Influence of Geometry and Measurement Methods: The text points to the deformation of acrylic panels in experimental chambers, which changes the direction of flow and the position of measured points. Errors also occur in the measurement of velocity in ducts using an anemometer (blocking effect) and in optical methods (LDA/PIV) due to inaccurate assembly or inappropriate use of tracing particles.Achieving accurate results requires detailed consideration of both precise geometry and a high-quality computational mesh in simulations, as well as the elimination of all inherent errors in experimental methods.

The article discusses the utilization of controlled ventilation and Computational Fluid Dynamics (CFD) tools to optimize Indoor Air Quality (IAQ) and eliminate contaminants.Given the high uncertainty in boundary conditions during detailed modeling of contaminant spread (e.g., infectious disease transmission), it is recommended to focus on a simplified assessment of ventilation effectiveness using Age of Air (AoA) and Air Change Effectiveness (ACE).The work highlights critical pitfalls in the validation of CFD simulations and the experimental measurement of AoA, such as CFD Limitations, Experimental Inaccuracies, Influence of Geometry, and Measurement Methods.CFD Limitations: Commercial software shows issues with modeling more complex geometry (e.g., in the area of diffusers/outlets) and setting up the computational mesh, primarily failure to meet the y^+ criterion. This fundamentally affects the accuracy of the resulting velocity field and AoA.Experimental Inaccuracies: The measurement of tracer gas concentration (CO2) is burdened by high sensor error (on the order of tens of ppm), calibration problems, and the sensitivity of sensors to direct airflow.Influence of Geometry and Measurement Methods: The text points to the deformation of acrylic panels in experimental chambers, which changes the direction of flow and the position of measured points. Errors also occur in the measurement of velocity in ducts using an anemometer (blocking effect) and in optical methods (LDA/PIV) due to inaccurate assembly or inappropriate use of tracing particles.Achieving accurate results requires detailed consideration of both precise geometry and a high-quality computational mesh in simulations, as well as the elimination of all inherent errors in experimental methods.

building ventilation; air age (AoA); CFD simulation; concentration measurement; validation; tracer gas; scaled model

building ventilation; air age (AoA); CFD simulation; concentration measurement; validation; tracer gas; scaled model

KUČÍREK, P.; ŠIKULA, O.

30.11.2025

SSTP

Bratislava

978-80-8284-050-9

16

24

9

https://www.sstp.sk/podujatia/kalendar-podujati/indoor-climate-of-buildings-2025-333_146sk.html