This paper describes an investigation into the ventilation performance and the indoor air quality of a portable classroom. Both field measurements and numerical simulations based on CFD (Computational Fluid Dynamics) technology were used. Field measurements in an unoccupied classroom used smoke to visualize the flow pattern, and hot-film probes to quantitatively measure air velocity. These field measurements provided the boundary conditions for CFD simulations and the experimental data to examine the accuracy of the CFD simulations.
Tracer gas measurements have Jong been used to quantify the performance of ventilation systems by exploring such scales as the air exchange efficiency, the local mean age of the air, the residence time distribution and so on. The present work deals with a numerical reexamination and calibration of some relations previously derived from tracer gas analysis.
The Building Air Tightness is an important parameter on ventilation systems performanceand energy losses.Yet, the total amount of leakage is as important on performances as their effective positionin the room.Some calculations have been run according to prEN 13465 from TC156 WG2 for differentbuildings (single house, dwellings and commercial buildings) varying air tightness, valueand repartition for different ventilation systems (natural, mechanical exhaust, mechanicalexhaust and supply).All these calculations have been compared focusing on ventilation losses during heatingseason in Paris.So
This article briefly describes a research program undertaken by the National Institutes of Health Office of Research Services to investigate ventilation performance of different laboratory configurations, and their affect on the hood. It focuses on some specific recommendations identified by the work which should help designers optimise performance. The intent is to provide a basis for guidelines to maximise lab hood containment performance, while minimising the impact of the lab layout and ventilation system.
Until now, there is no widely accepted way to express any index for this purpose and takinginto account the large variety of possible pollutants. Things can be simptied if the aim k tocompare different systems and strategies rather than to give an absolute value of quality.For the study of a pollutant source, the main important point for comparison is the pattern ofits production, whatever this pollutant is. The detailed data for each inhabitant is the curve ofthe number of hours above a pollutant level concentration.
As everybody knows, today the air quality of an indoor environment may have several effects on our health; the beginning of serious breathing pathologies and of some forms of cancer, are with no doubt due to the presence of polluting and extremely noxious agents in the places we most frequently use. That's the reason why it is very important that indoor rooms are correctly aired also in our homes where, due to several incidental factors, the healthiness of the environment is still guaranteed by the mere and discretionary operation of users of opening the windows.
Smoking restrictions in the workplace and increased health consciousness at home have seen a sizable reduction in the number of spaces where smoking is permissible. The aim of this study was to investigate the effects of ventilation in public houses, one of the few remaining public spaces where smoking is still socially acceptable. Little is known about the situation with shared occupancies, where relatively large areas are intended to accommodate both smokers and non-smokers.
The ventilation system of a 60 seats conference room was retrofitted to improve indoor air quality. The old, mixing type installation was replaced by a displacement ventilation system. However, the building layout did not allow an optimum location of air inlets and outlets. It was therefore interesting to measure the actual performance of the new system. Using tracer gas techniques, the age of air was mapped within the room, and the ventilation effectiveness was measured in various configurations. The actual air flow rates were also measured in the ventilation system.
This paper presents results of a study where computational fluid dynamics (CFD) was the numerical tool used to analyze the ventilation performance in stations of the Buenos Aires Metro subway system. Both natural and mechanical ventilation options were studied. The study showed that although natural ventilation was sufficient to maintain the temperature criteria, it presented a potential egress problem by letting hot gases leave through the entranceways.
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