A critical review of ventilation effectiveness in naturally ventilated spaces from the perspective of sustainability and health

Ventilation effectiveness is a term which describes the ventilation supply air distribution characteristics in a space. The metrics used to assess ventilation effectiveness have a direct bearing on important design factors including, energy efficiency, indoor air quality and airborne infection risk. This study provides a critical review of the ventilation effectiveness literature, to document: i) the relationship between ventilation effectiveness and its relevant fields of application, ii) state-of-the-art knowledge of ventilation effectiveness in naturally ventilated buildings, iii) major shortcomings in the use of these metrics in the field and iv) recommendations for improvements in the application of such metrics.
The findings show that ventilation effectiveness studies in naturally ventilated buildings are relatively sparse and are often poorly implemented. In contrast, there has been much more work applying ventilation effectiveness concepts to mechanically ventilated spaces. Furthermore, critical analysis of ventilation effectiveness studies in naturally ventilated systems reveals that there are considerable shortcomings in existing studies. Common issues included: poor adaptation of methods intended for mechanically ventilated spaces to naturally ventilated spaces, drawing potentially misleading conclusions based on misapplication of established metrics, and a lack of robustness in the use of computational fluid dynamics methods for modelling ventilation effectiveness.
These shortcomings highlight the urgent need for ventilation effectiveness research focused on providing a better understanding of the influential parameters, in relation to designing and operating healthier and more energy efficient naturally ventilated buildings.