Many modern office and residential buildings in Sweden include an atrium. The atria are often mechanically ventilated and sometimes they are heated. Very little is know about the ventilation and air infiltration in built atria. These issues were examined in an apartment building with a non-heated and mechanically ventilated atrium, built in 1986 in Sweden. The ventilation of the atrium is coupled to the apartments.

The role of ventilation in the housing stack is to provide fresh air and to dilute internally-generated pollutants in order to assure adequate indoor air quality. Providing this ventilation service requires energy either directly for moving the air or indirectly for conditioning the outdoor air for thermal comfort. Different kinds of ventilation systems have different energy requirements. Existing dwellings in the United States are ventilated primatiy through leaks in the building shell (i.e., infiltration) rather than by mechanical ventilation systems.

A total of 177 measurements have been performed in apartments in multi-story buildings without mechanical ventilation. The buildings comprised renovated and non-renovated buildings built between 1930 and 1960. Measurements of air change rate and relative humidity have been performed using passive measurement techniques including a passive multiple tracer gas technique, the so-called PFT-technique. In each apartment the main bedroom has been investigated separately. In addition, the occupants completed a questionnaire concerning their use of the dwelling.

This paper reports results from the ventilation and air tightness measurements in Swedish dwellings as part of the 1992 Swedish Energy and Indoor Climate Survey (the ELIBstudy). The indoor climate in a random sample of 1200 single- and multi-family houses from the Swedish housing stock were investigated. Among different parameters the ventilation and the air-tightness of the houses were measured.

To predict the thermal and indoor air quality performance of vertical displacement ventilation systems using two-zone modeling, it is necessary to account for the different nature of the air flow due to thermal and contaminant mixing within these zones. Two zone modeling of vertical displacement ventilation was performed assuming piston flow in the clean zone, uniform mixing in the dirty zone, and no recirculation between the zones except via heat source plumes.