English

Several studies have shown that the lowest concentrations of contamination in operating theatres are achieved by using fabric covered laminar airflow systems. These systems are distinguished due to the low turbulence intensities in the protective areas. An examination in a special designed test facility was done to get further information about the relation between the turbulence intensity and airborne contaminations. In a first stage the dispersion of airborne contaminations was examined.

A new experimental set-up to investigate the physical process of dust deposition and resuspension on and from surfaces is introduced. Dust deposition can reduce the airborne dust concentration considerably. As a basis for developing methods to eliminate dust related problems in rooms, there is a need for better understanding of the mechanism of dust deposition and resuspension.

Task-ambient air conditioning system is one of the systems developed to achieve quality indoor thermal environment and energy conservation simultaneously. The purpose of this study is to find the optimum supply air conditions of floor air outlet required to make thermally comfortable environment in the task area without cold draft. To achieve the purpose were carried out the experiments with subjects, who were allowed to control the supply air volume and the direction of inclined jet according to their tastes.

The process of air exchange can be described through both planar and spatial network system. It depends on a few random variables (those related to climate) and also on controlled variables (i.e. those like arrangement, etc.). Consequently, the air exchange problems are solved only approximately. In order to avoid that, a neural model was applied as well as estimation in the so-called learning process with simultaneous weight correction. On the basis of comparison with experimental data it can be claimed that solutions presented in the paper demonstrate high result congruence.

This paper introduces the infrastructure of Microflo CFO modelling system in conjunction with the virtual simulation environment. The theoretical basis is described and particularly the graphical user interfaces for pre and post processing are described in detail. Features of the Microflo system are further demonstrated through its application in the design projects.

Cheap 3D models for visualization of room ventilation applications are now available. VRML (Virtual Reality Modelling Language) is found to be a good format to describe buildings, rooms and furniture. A 3D model in VRML can be placed on an World Wide Web www page and others can see the model in "Walk Through" mode. Use of VRML is described with examples as for instance in planning of measurements and as a basis for geometry in CFD calculations. The advantage of 3D and VRML is that it is much easier to see, find and correct problems than using traditional drawings.

Future information age technology will demand cleaner and more cleanrooms for the manufacture, assembly and repair of electronic components. Many special processes can be very sensitive to trace contaminants which are not removed by conventional air conditioning, filtering and distribution. High efficiency particulate air filters, high velocity streamline air flows, relatively dry air, clean ducts and plenums, cooling, noise reduction and perhaps disinfection are needed.

The concept of air exchange efficiency of ventilation, a quantity entirely determined by the spatial distribution of the local mean age of air, is discussed. A divergence-type conservation equation for the local mean age of air is derived. This equation is solved numerically for a room ventilated by the desk displacement ventilation concept, using a CFO-routine. The CFO-calculated mean-age-of-air pattern is compared with mean age results from tracer experiments in a corresponding laboratory configuration.

The occupants of buildings are exposed to a range of aerosol contaminants, of both indoor and outdoor origin; at present, filtered mechanical ventilation is the only effective means of airborne particulate control in polluted urban areas. Significant energy costs may be incurred, however, through the large pressure drops associated with membrane filtration. An alternative to filtration might be the enhancement of aerosol deposition on a protruding surface which is parallel to the incoming airflow direction, but which does not significantly retard the airflow.