Evolution of CO2 concentration in indoor-room environments with different ventilation modes
Measuring and controlling ventilation rates (VRs) in buildings is important to meet requirements on indoor air quality and energy efficiency. Measurements of CO2 steady-state concentrations can be used for this purpose, but the accuracy of this method is limited, and reaching saturation under realis...
| Autores: | , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2026 |
| País: | España |
| Institución: | Universidad Nacional de Educación a Distancia |
| Repositorio: | e-spacio (DSpace). Repositorio Institucional de la UNED |
| Idioma: | inglés |
| OAI Identifier: | oai:dnet:e-spacio(ds_::961bf6eb26e0016da217b29a8f8b53e6 |
| Acceso en línea: | https://hdl.handle.net/20.500.14468/32712 |
| Access Level: | acceso abierto |
| Palabra clave: | 12 Matemáticas 22 Física indoor air quality indoor CO2 concentration CO2-balance model mixed-mode ventilation ventilation rate room occupancy estimation ODS 3 - Salud y bienestar ODS 9 - Industria, innovación e infraestructura |
| Sumario: | Measuring and controlling ventilation rates (VRs) in buildings is important to meet requirements on indoor air quality and energy efficiency. Measurements of CO2 steady-state concentrations can be used for this purpose, but the accuracy of this method is limited, and reaching saturation under realistic constant occupancy levels can be challenging and time-consuming. Here, the general solution of the CO2-balance equation is employed to model and fit transient CO2 concentrations measured in large indoor rooms at high occupancies. The evolution of CO2 concentration was recorded for real-use conditions over several hours or days in a conference room, an auditorium, and a large multipurpose room during a multitudinous conference. Each space has one or several modes of ventilation, namely a ventilated air-conditioning system, natural ventilation, and/or infiltration. Total and mode-specific VRs were derived, evaluated, and compared with current standards. By assuming mean CO2 generation rates per person, room occupancies during different events in each room could be estimated. The same procedure was repeated for a regular coworking office, demonstrating the applicability of this method to smaller rooms and lower occupancies. Additionally, a non-dimensionalization of the balance equation is employed to assess the accuracy of steady-state CO2 concentrations predicted by transient-state fits. The obtained non-dimensional relations provide a basis for designing ventilation systems in new buildings to avoid excessive CO2 levels at maximum occupancy and ensure sufficient ventilation. These results emphasize the importance of adequate ventilation to maintain acceptable indoor air quality for variable or even low occupancy. |
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