Ventilation systems play an important role in providing a good indoor air quality in dwellings. Mechanical exhaust ventilation systems implement natural vents, also called trickle vents, to supply outdoor air to the dwelling. The airflow through these natural supply vents depends on the natural driving forces, i.e. wind and the stack effect, which vary in time.
This study examines several interventions to minimise the influence of the stack effect and wind on the operation of a classical mechanical exhaust ventilation system as defined by the current Belgian standard NBN D50-001 (1991). These interventions contain the overall use of smaller natural supply vents, additional mechanical extraction in the bedrooms, the use of natural supply vents only in the hallway, the use of mechanical transfer openings, balanced airflow rates per building level, increased air flow rates and the use of larger transfer openings. This paper covers a simulation study using CONTAM to investigate the effectiveness of the different interventions on the operation of a mechanical exhaust ventilation system in two types of single-family dwellings, i.e. a detached 3-bedroom dwelling and a terraced 2-bedroom dwelling. The operation of the mechanical exhaust ventilation system is evaluated in terms of the exposure of the occupants to CO2 in the living spaces.
All of the above described interventions have a positive effect, to a greater or lesser extent, on minimising the influence of wind and the stack effect on the operation of the mechanical exhaust ventilation systems in both types of dwellings. However, some of the interventions are not as efficient to be considered as a valid solution to minimise the influence of the stack effect and wind.