An even distribution of room air can improve indoor air quality, lower energy costs, and create thermally comfortable environments. This paper investigates the influence of the design of plaque diffusers on the efficiency of supply air. For better comfort and more accurate observations, the isothermal flow investigation was made in a small scale chamber with the air supply and exhaust on opposite walls. The supply air was spread radially and symmetrically over the vertical inlet wall. Plaques of different sizes, both solid and perforated were tested.

Cooling ceilings are more and more proposed, in order to eliminate excess heat in office buildings without consuming much energy in air transport. On the other hand, piston ventilation is proposed to efficiently eliminate contaminants. These two systems may however interact and experiments were planned to look at these interactions. Measurements of the age of air and air change efficiency were performed, together with more classical temperature and air velocity measurements, on various ventilation systems installed in the test chamber of Sulzer Infra, in Winterthur.

Ventilation of buildings is necessary, both to insure adequate indoor air quality and to protect the building itself against condensation and mould growth. On the other hand, ventilation rates must not lead to excessive energy consumption. French regulation doesn't appreciate directly the indoor air quality but fixes requirements for the value of exhaust stale air in service rooms ; furthermore heat losses related to cross ventilation due to wind effects are also taken into account.

A combined thermal and ventilation model has been used to investigate the seasonal variation of air infiltration rates and ventilation heat losses in modern industrial buildings. The model was initially compared to measurements of ventilation rates, temperatures and heating loads in such a building, and was found to agree well. The model was then used to predict infiltration rates, temperatures, ventilation heat losses and space heating loads for a standard heating season for that building.

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.