Traditionally air has been supplied from the ceiling to the occupants below opposing the buoyancy effects due to heat convected from people, lights and machines. There has also been concern that if air supply outlets are installed at low level near people the chances of draughts and noise are high. The development of swirl air diffusers in Sweden and Germany overcomes these problems and allows a wider consideration of air distribution systems when designing buildings. This also offers flexibility in planning the distribution of electrical systems and piped services.
In displacement ventilation systems, air flow rates, temperature and the design of the air supply device strongly influence the parameters which decide the thermal comfort. This paper reviews experiments and theoretical models which show the connection between t.hese parameters. It is indicated that the Archimedes number of the supply air is the parameter which decides the air velocity in the area close to the floor. (The Archimedes number is the ratio between buoyancy and inertia forces).
Outdoor air pollution can have a bearing on the effectiveness of indoor air and the quality of ventilation. There is a pressing need to reflect on the potential type and effect of occurrences (e.g. smog, or chemical accidents) and to develop technical, operational and organisational measures which must be taken with mechanical ventilation units in the case of polluted outdoor air situations. A polluted outdoor air situation is present when a ventilation process leads to the intake of pollutants in the interior and to the enrichment of these pollutants to an unacceptably high concentration.
This work deals with problems of the air humidity in inhabited dwellings. A new approach is presented here which renders the definite diagnosis of humidity problems possible. The room air humidity from two buildings with different air ventilation systems with eight dwellings each is examined, The efficiency of the different ventilation systems is presented applying the new value, the so called "standardized room air humidity".
To avoid the shortcomings and problems that occur in today's ventilation systems a ventilation concept for future dwelling-houses is under development. The concept responds to the way of living and building in the future. The real living functions are chosen to design principles, that's why the system has to be capable of operating at varying air flow rates. The building in the future is based on a hierarcical modulated system, from which, with a small set of standard components can be assembled versatile alternatives.
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