Computational fluid dynamics (CFO) was used in a study of the air flow characteristics in the occupied building zone. Correlation equations between the mean air speeds and the percentage dissatisfied with the macroscopic flow numbers were derived. Ten macroscopic flow numbers including the total ventilation rate, the air change rate, ventilation rate, air diffusion performance index, modified jet momentum number, two new flow numbers and three expressions of jet momentum ratio were investigated.
The properties of particulate filters and gas adsorption filters have been studied to determine the opportunities available for effectively cleaning the outdoor air supplied to buildings located in urban environments. Class F85 fine filters were studied to determine their collecting efficiency for both atmospheric dust and particulate P AH. Activated carbon adsorption filters were tested to establish their collecting efficiency for toluene, m-xylene and benzene in the concentration range of 1-10 ppm. Long-term tests were also run on a carbon filter in a building in central Stockholm.
The pressure field in fluid systems reflects the flow configuration. Measurements of the pressure along the perimeter of a slot ventilated room have been conducted for different room sizes. The momentum of the jet at the end of the room is decreased with increasing room length. The impingement region (region where the influence of the opposing wall is present) starts, independent of room size, when the distance from the supply device is about 70% of the room length. Corner flows could not be predicted by CFD using the linear eddy viscosity or standard stress models. However.
The design of natural, including passive, ventilation systems assumes one of two genericforms: the nasty design problem where the designer seeks to size ventilation openings givenclimatic conditions and thermal comfort criteria or the nice design problem where the designerseeks to size ventilation openings given climatic conditions, indoor temperature distributions,and specified airflow rates - presumably determined from separate thermal or air qualityconsiderations.
Includes sections on modelling and control algorithms, equipment and envelope characteristics, ventilation performance and building airtightness, ventilation strategies and pollutant transport, NATVENT - overcoming technical barriers, and cooling and indoor air quality in commercial and public buildings.
This paper considers methodologies how desired level, target level, of industrial air quality can be defined taking into account a feasibility issue. The method is based on the health-based risk assessment and the technology-based approach. Because health-based risk estimates at low contaminant concentration regions are rather inaccurate, the technology-based approach is emphasized. The technological approach is based on information on the prevailing contaminant concentrations in industrial work environment and the benchmark air quality attained with the best achievable control technology.
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