Exposures to respirable suspended particles (RSP) and both the particulate and vapour phases of environmental tobacco smoke (ETS) were monitored in eight European cities. Over 1500 housewives and office workers participated in the studies by wearing personal monitors over a 24-h period to assess exposures in the home and workplace. Based upon median 24-h time weighted average (TWA) concentrations, the most highly exposed subjects throughout Europe were office workers living and working with smokers.
Under the conditions that the air in each room is in the state of perfect mixing and ventilation is in steady state, a method to estimate steady state concentration distribution to match an arbitrary contaminant generation distribution is proposed, using concentration data obtained from short-time tracer gas experiment. Also, a method is proposed, which is used to estimate ventilation rate by adding other available equations.
A three-dimensional mathematical model to solve the mixing, displacement and vortex ventilation systems in the removal of pollutants with a thermal source is described. The study carried out to investigate the effectiveness of each of the individual ventilation systems showed that the vortex ventilation system performed better than the other two systems in providing moderate occupancy thermal comfort but very effective in purging pollutants away from a typical office room environment
In this work a numerical model that permits to simulate the human body thermal system is presented. This computational model is based on the integral energy balance equation for the human body tissue, arterial and venous blood and mass balance equation for the blood.
The purpose of this study is to identify the ventilation effectiveness of a displacement ventilation system in a concert hall with 501 seats, where a large amount of outside air is required for ventilation. Displacement ventilation was considered appropriate to reduce the amount of outside air. Light bulbs were placed on all the seats to simulate the heat source from the audience. From the measured concentrations, the local mean age of air at the breathing point with the displacement ventilation system was found around one third of that of the fully mixed condition.
The calculation of the infrared absorption in humid air (Schenker et al. 1995) has suggested an influence on the temperature and velocity profiles of the natural convection boundary layer. The profiles have been measured and confirm a small effect on the profiles in the laminar region of the flow but a strong one on the transition from laminar to turbulent flow. In a first approach based on the analytical solution for the conduction regime expressions could be deduced showing at least qualitatively the same modification of the temperature and the velocity profiles as measured.
The purpose of the presented investigation is the comparison between measured data of the laminar and turbulent mixed convection and their approximation by wall functions. New wall functions were implemented in a FVM-research-code using unstructured grids, which was developed by the author. Numerical results are compared with a turbulent closed cavity flow.
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.
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