In this study, we monitored the carbon dioxide (CO2) concentration in a high-speed train passengercabin by the in-situ non-dispersive infra-red (NDIR) method in order to investigate the effects of variousfactors, such as number of passengers and the presence of tunnels on the CO2 concentration levels.We found that the CO2 concentration was strongly related with the number of passengers andcorrelated with the presence of tunnel regions. The CO2 concentration increased with increasingnumber of passengers and increasing tunnel residence time.
Heating, Ventilation and Air Conditioning (HVAC) systems, often do not achieve the same level as itachieved at commissioning. An appropriate system analysis for Fault Detection and Diagnosis (FDD)can save material and energy significantly. FDD technology optimizes the use of the components ofthe system, so that they only be replaced or corrected when they are no longer useful. This paperpresents a complete methodology of introducing warning signal component in building managementsystem, which gets automatically activated as and when faults occur.
We have sought to accurately quantify automobile HVAC air flow rates in four passenger vehicles,under a range of different ventilation settings and speeds. We used Sulphur Hexafluoride (SF6) as atracer gas, coupled with a portable doser/sampler system to quantify flow rates and leakage.Results of this work indicate a linear increase in HVAC air flow rate with increasing vehicle speed forall vehicles. Older vehicles were much less airtight than newer vehicles, a likely reflection on improveddesign and reduced door seal deterioration observed in the newer vehicles.
It is well known that volatile organic compound (VOC) emissions from construction materials and officeappliance occasionally have influence on human health. It is a social request that manufacturersreduce VOC emissions from their products. To measure emissions from materials, a high-precisionchamber is required that can control environmental conditions such as ventilation, temperature,humidity, air flow, and VOC concentrations.
Conventional method to predict ventilation rate induced by wind is based on the orifice equationassociated with the discharge coefficient and wind pressure coefficient. In the cross-ventilationphenomena, however, this method has a problem due to the difficulty to predict resistance of thebuilding related with total pressure loss. In this paper, therefore, the stream tube caught by the inletopening is analyzed to investigate the pressure loss due to the transformation (and possiblyconvergence and divergence) of the stream tube.
The wind pressure coefficient is the basic driving force of wind-induced natural ventilation. The windvelocity along the building wall is also important for wind environment in balcony (veranda) or windowsand is the moment of inertia for the air flowing into rooms. These two values of the five-storiedapartment building with/without veranda were measured by wind tunnel test using scaled model. Theexperimental conditions are the faade type, the shape of veranda and wind direction.
Since 1970s, kinds of condensing boilers (CB) have been widely applied in HVAC engineering, theirexit flue gas temperature is very lower, even down to about 40?-45?, and their thermal efficiency isvery higher, even up to about 107%~109%, based on low heat value. The application of CBs in HVACsystem or hot water supply system can increase thermal efficiency and reduce the consumption of fuel,because of the utilization of latent heat of vapour in the exit flue gas.
This study was performed to investigate an influence of ventilation rate change on the level of aerialcontaminants in the confinement pig building. There was not significant difference in total dust and totalairborne microorganisms among three levels of ventilation rate (p>0.05) whereas the increasedventilation rate lowered the levels of respirable dust and gaseous compounds (p
Increase in high-rise residential building has changed the envelope of residential building to aluminumcurtain wall which requires the use of the single-sided ventilation to be used instead of the crossventilation. It causes dissatisfaction mainly with indoor air velocity and ventilation volume. Therefore,the objective of this study is to improve the natural ventilation performance of high-rise residentialbuilding by opening design. To improve the natural ventilation performance in single skin faade, theeffect of different types of window will be evaluated.
The purpose of this paper is to analyze the indoor thermal environment and ventilation efficiencycreated by various heating and ventilation systems using CFD. In the case of one room, the value ofmean local air exchange efficiency????*1 of breathing zone*2 becomes about 1.0, because fresh airspreads completely in the room when air-conditioners are operated. In contrast, when air-conditionersare not operated, the mean ?? becomes smaller than 1.0, and the area of poor ventilation efficiencybecomes large.
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