As ventilation is a significant consumer of energy the rates of ventilation have often been minimized, particularly after the energy crisis in the early 70s, in order to reduce equipment and energy costs. This has caused in many countries indoor air quality problems. It has been shown that ventilation rates have adverse effects on communicable respiratory illnesses; on sick building syndrome symptoms; on productivity and perceived air quality. Often the prevalence of SBS symptoms is higher in air-conditioned buildings than in naturally ventilated buildings.
Underfloor air distribution (UFAD) strategy is gaining popularity during the last years, howeverresearches about the performance of such systems still need to be deepened.One of the appreciated features of this technology is the use of an underfloor plenum below a raised floor. This plenum is used to distribute the conditioned air in the rooms and makes possible to avoid large air ducts to be installed.
Arthur Rosenfeld cited a study showing that the huge link between IAQ and productivity in anoffice building and the serious initiative to improve indoor air quality will have a tremendous return. This study attempts to analyze the working spaces with different variances. The chamber measurements in the laboratory constructed in Shu-Te University will be taken, and the numerical simulation using CFD techniques will also be applied. The results from both should be compared. The different inlet layout of HVAC system, especially the UFAD system, and the boundary conditions will be discussed.
The air exchange rate is a determinant factor for the indor air quality in a given spaces. If it is lower than the required it may cause the so caled sick building syndrome. The ultimate result depends, obviously, also on the nature and strength of the sources emisions. In this work the natural
An experimental study was conducted in a field environmental chamber with the aim of comparingceiling-based mixing ventilation (MV) system and under-floor supply system (UF) from the perspectives of indoor air quality and thermal comfort. Six tropically acclimatized female subjects participated in the experiments and they were required to complete a set of questionnaire pertaining to IAQ and thermal sensation every 20 minutes during each exposure of 2 hours.
An experiment was carried out to determine the effect of photocatalytic air cleaning on perceivedair quality. Thirty-eight subjects assessed the air quality in a low-polluting, 108 m3 office, with pollution sources either present or absent behind a partition. The pollution sources were carpet, linoleum and chipboard. The office was ventilated with outdoor air at 0.6, 2.5, and 6 h-1. The air temperature was 22C and the relative humidity 40%.
The perceived intensity is investigated by a trained group of 10 to 15 persons. Until now fieldstudies have to be made at the location of interest. All members of a trained group have to visit e.g. a building in order to estimate the perceived intensity of the indoor air. The trained group is influenced by the local environment. This paper presents a new method to sample and to store air probes at arbitrary locations. The air probes can then be transported to the laboratory where a standard group test can be made in the neutral and clean environment of an air quality lab.
Amongst various sources of polluting substances the open space gas-range have an impact onthe quality of living spaces. Carbon-dioxide and nitrogen-oxides occurring during burning considerably impair the air quality. Emission of polluting substances has been examined in the Laboratory of Air Quality of Dept. of Building Service. The results of the research supported by the Ministry of Education (T0375 96) will be presented here.
In the light of ever increasing oil prices and rapidly depleting fossil fuel resources, energyconservation strategies in buildings become popular and necessary design goals. However, it is important to note that resulting poor ventilation in the occupied zones at part-load operating conditions or even unanticipated peak-load conditions due to a different occupancy pattern can often lead to major problems associated with poor Indoor Air Quality (IAQ).
A detailed study using Computational Fluid Dynamics (CFD) was conducted on the influenceof the difference in the effective diameters of air supply outlets (wind velocity, assuming the airflow rate to be constant) when using personal air conditioning with isothermal air currents. A method to analyze the new age of air (SVE3*) and the residual lifetime of air (SVE6*) was proposed and studied focusing on the individual supply openings and exhasut openings in a room with multiple supply openings and exhasut openings when using personal air conditioning.
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