English

Indoor aerosol particles, their concentration and deposition in displacement, their movements in two ventilated rooms are compared numerically. For the simulation of particle tracks, the discrete trajectory model is adopted whereas the Eularian method is used for solving the continuous fluid flow.

This paper reports mainly on field studies were indoor overnight CO2 levels are monitored along with outdoor ventilation rates in bedrooms where room air conditioners are employed.The results of laboratory experiments using two typical RACs (room air conditioners) are also reported and discussed.

The principle of displacement ventilation involves air supply and distribution in a room by upwards displacement, i.e. as direct as possible through-flow in the occupied zone in order to achieve high ventilation efficiency. In addition, air distribution by displacement generally makes it possible to supply a larger quantity of air than for conventional mixing ventilation, which requires concentrated supply at high velocity.

For that study, the constant concentration dosing method and the decay method were used to test air changes performances in an office equiped with a VAV mechanical ventilation system and in a domestic apartment with natural ventilation . The measurement results from those two tracer gas methods are compared.

There is a resurgence of interest in naturally ventilated offices. Most of the time, cooling the buildings is possible with the opening of windows. Simulations with the softwere TAS were made and showed that window opening allow a sufficient day or night ventilation rate, even if wind characteristics are not favourable. The optimal size, shape and location of the window apertures to reach sufficient ventilation rates has been studied along with the impact of the wind orientation and the building degree of protection on these ventilation rates.

For that study, IAQ measurements were carried out in 3 residential Singapore dwellings. CO2 levels were higher in air-conditioned bedrooms than in naturally ventilated bedrooms. Another survey demonstrated that almost all occupants using air-conditioners while sleeping presented one or more SBS symptoms than when using natural ventilation.

How to avoid or reduce the influence of suddenly released contaminant when emergency occurs ? A 3D Full scale room with displacement and mixing ventilation system is numerically studied assuming contaminant released at certain positions in the room. IACS is adopted as an index that can be applied to determine ventilation strategy with the aim of defending indoor environment against contamination.

Investigations in six car parks were carried out. Measurements of carbon monoxide levels were made during the peak hours to compare the performance of the different types of ventilation systems : the performance is better with a combined supply and exhaust system than the exhaust only system though more energy is consumed.

For that study the measurement of parameters in the indoor environment were carried out with a simultaneous survey with questions dealing with elements of the indoor environment, health status and health problems. That study reveals a significant role for the psychological state and psychological factors of the respondents of natural ventilation when sujectively describing the indoor environment.

In experimental chambers, the ventilation effectiveness and thermal comfort of a task ventilation system has been investigated. The method and results of the experiment are presented in this paper. The conclusion of that thermal comfort survey is that task ventilation systems maintain the occupants thermally comfortable while saving energy.