mechanical exhaust ventilation

More than 70% of the dwellings in Chile were built before 2000, when the use of thermal insulation in the roofs of residential buildings became mandatory. This explains why less than 2% of dwellings are considered energy efficient. Social housing is no exception. Several studies have shown poor thermal performance of the envelope of social housing throughout the country, with low levels of thermal comfort and indoor air quality that affect the health of its occupants.

Chile has 1,626 social housing complexes with a total of 350,880 dwellings. Several studies have demonstrated a low thermal performance and high air permeability of the envelope of social houses throughout the country, causing surface condensation on walls, high heat losses in winter and low levels of thermal comfort for their occupants. The presence of high levels of indoor pollutants and/or indoor humidity has also been observed, causing respiratory and cardiovascular diseases in the occupants.

Ventilation systems play an important role in providing a good indoor air quality in dwellings. Mechanical exhaust ventilation systems implement natural vents to supply outdoor air to the dwelling. Natural driving forces, i.e. wind and thermal draught, influence the flow rates through these supply vents. Therefore, the flow rates depend on the weather conditions and vary in time. This study considers the influence of the wind and thermal draught on the operation of a mechanical exhaust ventilation system in a reference dwelling.