A general model (semi empirical) to predict temperatue efficiency of displacement ventilation systems.

Temperature efficiency is an important index to estimate the ventilation effectiveness. Usually ,the temperature efficiency is determined through field or model tests such as gas-tracing technology. The heat source structure(location, size, heat emission, etc) has a strong effect on the temperature efficiency. The heat sources present themselves or may be arranged in three basic models:(A)heat sources uniformly distributed in the space; (B) heat sources uniformly distributed on the floor; (C)concentrated heat sources at the bottom of a room.

Study of the ventilation efficiency under some typical air flow conditions in a mechanically ventilated room.

The present study deals with indoor air quality and is mainly based on an experimental work. The experimental set up is a full scale test cell with a ventilation system which comprises a fixed air supply and a mobile extract. A source of pollutant continuously supplies tracer gas at the centre of the cell. We carried out 12 tests under steady state and with various conditions. The test parameters were the exhaust location, the fresh air now rate and the supply air temperature.

Experimental study of ventilation performance in dwelling-cells.

In order to assess ventilation systems, ventilation and thermal comfort parameters are calculated. Parameters are temperature and ventilation efficiency and PMV I PPD. Two ventilation configurations are set: the supply grille is under the ceiling and tests are performed for 2 exhaust positions. Both are opposite the ceiling: the first one is under the ceiling and the second one is on the floor. In regards with extract position, the ventilation system is better when extract is on the floor. It appears that the air renewal does not influence neither ventilation nor temperature efficiency.