Improvement in methods of air flow pattern scale modelling in large enclosure requires above all, précising the conditions necessary in the model in order to maintain Reynolds number independence of the mean flow, as well as defining ways in which the flow turbulent structure could be simulated. The paper presents the results of experimental analyses of air velocity fields in scale models in the range of Reynolds number 1850 to 98000. The field maps of air velocity mean value were tested.

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.

Previous full scale experiments gave us a global and qualitative understanding of the gas circulation in a ventilated room in case of fire. In order to go thoroughly in the knowledge of these phenomena, we have built a scale model to perform more precise temperature measurements and more complete tracer gas experiments. The results show the existence of two zones when the air inlet is near the floor. At the opposite, when it is near the ceiling the room can be considered as a one single zone.

Displacement ventilation is acknowledged to be an efficient system for the removal of contaminants and excess heat from occupied zones of rooms, this system is aiming at supplying clean undiluted supply-air directly to the zone of occupation. Air flow rate, temperature and the design of the supply device strongly influence the parameters that determine thermal comfort. In the paper, one kind of displacement ventilation systems - ohair air supplying system is investigated.

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 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.

Contaminant dispersion and potential draft risk in a workshop with displacement venti.la tion were investigated with computational fluid dynamics (CFD) techniques. Three factors were considered: the location of the worker, the temperature of the supply air and the supply air flow rate. The capacity of CFD is demonstrated in optimizing the operation of a ventilation system by weighting two significant aspects, i.e., the indoor air quality and the worker's thermal sensation.

A test room and measurement system were developed for the full-scale measurements of the active displacement air distribution. The room represents a 3-meter wide module of a larger hall. The requirements for the room included minimisation of the errors caused by air leaks, thermal conductance and flow obstacles. The measurement of the flow pattern is carried out with ultrasonic and thermal anemometers. Automated traversing system was built to move the sensors in the vertical symmetry plane of the room.

One of the major factors in human comfort is the air quality, which occupies a specific environment and is usually renewed through natural ventilation. However, isolated underground spaces do not benefit from this factor and are often subject to high relative humidity, poor air quality, pollutant emissions and penetration of moisture from the surrounding soil and ground base. Due to such negative characteristics, underground spaces are generally recognized as undesirable living environments by most of Koreans.