English

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.

Several new scales have been developed to quantify fresh air diffusion and contaminant dispersion in ventilated spaces. The local purging effectiveness is proposed for analyzing the individual contribution of each supply opening for a multi-inlet system. The local specific contaminant-accumulating index is defined to indicate the tolerance of a ventilation flow to contaminants. Furthermore, the regional purging flow rate, Up, is re-embodied in a simple expression different from the previous description.

A Computational. Fluid Dynamics technique is employed to predict the two dimensional turbulent air flow which is created by an Aaberg slot exhaust hood reinforced by a two-dimensional wall jet flow. The standard turbulent k-e model, control volume method and SIMPLE algorithm are tised to simulate the air flow. The numerical results for the effect of the Aaberg slot exhaust hood on the air flow pattern, shape of the capture region and the velocity distribution of the capture region in the system are presented.

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.

At Hermann-Rietschel-Institute systematic tests of the limits for the ventilation with openable windows are under way. The parameters temperature distribution and air velocity are the most attended values. Window ventilation in office buildings has limits in application. An open window can remove cooling loads out of the room. With one window and a room with a depth of 5 m, the maximum cooling load is about 20 to 30 W/m2. These limits are determined by air velocities within thermal comfort.

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.

This paper discusses the experimental study of direct delivery of cold air into a full scale environmental chamber using different diffusers, i.e. a multi-cone circular ceiling diffuser, a vortex diffuser and a nozzle type diffuser. Comparisons have been made of the following: mean flow patterns, temperature distribution and condensation risk. The vortex diffuser exhibits a higher induction effect than that of the nozzle type diffuser. However, the air speed generated by the vortex diffuser is generally lower than that of nozzle type diffuser.