A test room which was built at a scale 1:5 to the original one has been used to investigate air-conditioned rooms. The original room was specified by the international project IEA ANNEX 20. A lot of experiments were made on different inlet geometries and air change rates. Velocities and turbulent quantities were measured not only in the inlet plan but also in the room itselfby means of hot wire anemometry. The ammonia absorption method according to Kruckels has been applied to determine the heat transfer coefficients at the walls. Qualitative results were obtained by laser light sheets.
The efficiency of removing excess heat by employing mixing ventilation is based on the properties of jets. Therefore the behaviour of jets in enclosures is important. A correct supply design is essential otherwise the jet will separate from theceiling and drop into the occupied zone. This will give rise to unacceptable high velocities. the basic properties of jets in ideal situations like an infinite space are well known. However, in a room the jet interacts with the room air and the room surfaces.
A new miniature mechanical ventilation system with both supply and extract air and an air-to-air heat exchanger has been developed in Great Britain and Denmark. The system which is intented to ventilate a single room has the dimensions of a shoe box and can be placed/installed on the inside wall in an existing air vent. The system can operate with two air flows, 40 or 70 m³/h. At the low speed the noise is insignificant, intended to be "not disturbingN in sleeping rooms.
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.
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