This paper presents an analysis of the emission of chemical compounds and their diffusion in a room by the technique of computational fluid dynamics. A polypropylene styrene-butadiene rubber (SBR) plate was chosen as the TVOC emission source. The emission rate and room-averaged concentration are analyzed under various conditions of ventilation rate and temperature. Further, the concentration distribution of TVOC within a room is also examined and evaluated from the viewpoint of ventilation efficiency.
In many new buildings the indoor air quality is affected by emissions of volatile materials. The emission process may be controlled either by diffusion inside the material or evaporation from the surface but it always involves mass transfer across the boundary layer at the surface-air-interface. Experiments at different velocity levels were performed in a full-scale ventilated chamber to investigate the influence of local airflow on the evaporative emission fr-0m a surface.
A mathematical model is developed to predict Volatile Organic Compound (VOC) emission rates from homogeneous materials. The model considers both mass diffusion and mass convection processes in the boundary layer between the material surface and the air flow. Establishing the relationship between the surface air flow and emission rate: the model therefore can predict the material emission rate under different environmental conditions.
The purpose of this paper is to evaluate the performance of 4 kinds of ventilation systems from the point of view of indoor air pollution and energy need during heating season under Japanese conditions by numerical simulation. TVOC was selected to characterize the indoor air quality impact to residents. The results show that in the case of mechanical exhaust ventilation system, TVOC level is the highest among all the systems. Mechanical central supply and exhaust ventilaton system shows its advantages for minimizing energy consumption and maintaining an acceptable indoor air quality.
The Field and Laboratory Emission Cell (FLEC) is a tool for non-destructive emission testing of materials with even surfaces. Measurement of air velocities inside the cell showed an inhomogenous flow field with a high-velocity area around the inlet axis and an area of comparatively low air velocities perpendicular to the inlet axis. These results suggest that punctual emission sources may lead to different VOC-concentrations depending on the position of the source.
Emission of volatile organic compounds (VOCs) from materials is traditionally determined from tests carried out in small-scale test chambers. Howeyer, a difference in scale may lead to a difference in the measured emission rate in a small-scale test chamber and the actual emission rate in a full-scale ventilated room when the emission is fully or partly evaporation controlled.