A three-dimensional mathematical model to solve the mixing, displacement and vortex ventilation systems in the removal of pollutants with a thermal source is described. The study carried out to investigate the effectiveness of each of the individual ventilation systems showed that the vortex ventilation system performed better than the other two systems in providing moderate occupancy thermal comfort but very effective in purging pollutants away from a typical office room environment

The paper presents a mathematical model, implemented in a general computer code, that can provide detailed information on velocity and temperature fields as well as pollutants concentrations prevailing in three-dimensional buildings of any geometrical complexity, for given external meteorological conditions. The model involves the partial differential equations governing flow and heat transfer in large enclosures containing heat sources. Turbulent flow is simulated and buoyancy effects are taken into account.

We examine transient displacement flows in naturally ventilated spaces that are subject to an increase in internal heat gains as in, for example, an empty lecture theatre which is then occupied by an audience. Heat gains create a layer of warm air at the ceiling which initially increases in depth and temperature, and descends towards the occupied regions. A theoretical model is developed to predict the time-dependent movement of the interface that separates the warm upper and cool lower layers of air, and comparisons are made with the results of laboratory experiments.

The purpose of this study is to find more information of the complicated air flow pattern in the SchOnbrunn palace. The aim is to improve the control of the air infiltration. We have used a passive tracer gas technique, a special case of the constant injection technique, called the homogeneous emission technique. The results gives Air Change Rate's (ACH) of 0,7 to 1,7 in different rooms and parts of the palace. Wind driven ventilation dominates stack driven ventilation. We found a considerable air flow between floors.

The purpose of this study is to identify the ventilation effectiveness of a displacement ventilation system in a concert hall with 501 seats, where a large amount of outside air is required for ventilation. Displacement ventilation was considered appropriate to reduce the amount of outside air. Light bulbs were placed on all the seats to simulate the heat source from the audience. From the measured concentrations, the local mean age of air at the breathing point with the displacement ventilation system was found around one third of that of the fully mixed condition.

A numerical simulation method is developed for predicting the effective radiation area and the projected area of a human body for any postures. This method is based on the solar heat gain simulation for buildings. To confirm the validity of the present method, predicted effective radiation area factors and projected area factors for both standing and seated person are compared with those by the measurements. It was found that predicted values agree quite well with those by the subjective experiments within 10% accuracy.

The paper deals with the differences in the air quality between that perceived by the occupants (breathing zone) and that in the occupied zone as a whole. An environmental chamber with a displacement ventilation system has been used to carry out the measurements with the presence of a heated mannequin and heat sources. Measurement of the age of air distribution in the chamber were carried out for different room loads. It has been found that the perceived air quality for a seated mannequin is about 40% better than the average value in the occupied zone.