Concerning pollution in Hong Kong, the situation is particularly serious in public transfer locations such as public taxi transfer interchanges. Those locations are normally built at ground level under large building complexes, and poorly ventilated. The exhaust gas from vehicles are trapped and the air within those locations is smoky, filthy, and harmful for the passengers. This paper deals with a study on pollutant dispersion and distribution inside that type of sites at off-peak and peak hours. Measurement and analysis of field data are presented.
The second part of the paper deals with the measurements of the indoor thermal environment and the ventilation performance of a commercial kitchen.Measurements were made with a tracer gas (SF6) which is non-toxic and odorless.A smoke machine (ROSCO) was placed on the floor of the middle of the kitchen while operating the ventilated ceiling system. Air inlets near the floor or at the lower parts of the walls brought fresh air in the lower part of the kitchen and pushed the smoke upward.The results almost agreed with the results of the previous numerical simulation ( in part 1).
The first part of this paper deals with the performance of a ventilated ceiling system. Field measurements were made in a kitchen of a dietitics school in Kyoto practising mass cooking. The kitchen was half equipped with air canopy hoods to compare with the ventilated ceiling system.
A numerical simulation was conducted with CFD in order to understand the trends of the indoor thermal environment of the kitchen.
This paper aims at showing the difference between the two approaches used to evaluate the capture efficiency of a local ventilation system : an experimental research using the tracer gas method ( CO2) and the numerical modelling using CFD code ( STAR-CD). Comparison between the two methods show that the CFD modelling can provide results in good agreement with the experiment.
An innovative thermal comfort meter has been developed. It can simulate the human body evaporative losses. The sensor has been calibrated in a climatic chamber with different air temperature, velocity and humidity.
Three methods : step-up velocity change, step-down velocity change, and the cut-off frequency method were tested for the dynamic response of two low velocity thermal anemometers.This paper had the objective to identify whether those methods recommended in the standards and guidelines always succeed in determining accurately the frequency response curves and the time constant of low velocities anemometers.
The experiment was conducted by means of a scaled-room wtih floor supply ventilation system, it intended to know the vertical distribution of contaminant concentration emitted from a human body. The validity of the models has been proved in so far as the calculated concentrations were almost equal to the measured values.
Measurements are made first in a full-scale room ventilated with a mixing ventilation, and later with a displacement ventilation. A new method to design mixing ventilation is established. A comparison shows the thermal comfort obtained with the two systems.
This paper presents the behaviour of a thermal plume combine with a forced ventilation. A method to locate the position of the thermocline in a ventilated room is shown. It also gives and compares the results obtained by means of a solutal simulation on an hydraulic model and from full-scale experiments in a climatic chamber.