Subjective experiments were conducted during the summer season and the winter season in order toclarify the multiplied effects of humidity and indoor chemical pollutants on subjective comfort and productivity. Lower concentration of formaldehyde was observed at low humidity than at high humidity. Subjects rated the acceptability of air lower at the beginning of the exposure in the environments polluted with formaldehyde. On the other hand, lower humidity caused subjects to rate air quality higher in clean air.
The IAQ characteristics and the corresponding health symptoms and thermal sensation of the occupants of child care centers in Singapore under 3 different ventilation strategies are reported. The 3 child care centers studied were centrally air-conditioned and mechanically (ACMV) ventilated (Case A), naturally ventilated (Case B) and hybrid (natural and air-conditioning) ventilated (Case C).
Experiences from cleanroom installations has frequently shown that displacement ventilation has a much higher efficiency than mixing ventilation with respect to particle and CO2 reduction, cooling efficiency etc. Another cleanroom experience is that low particle concentration benefits asthma and allergy sufferer. Low particle concentrations reduces the impact of other pollutants and enhance the quality of life for everybody. In an office, the level of discomfort this means less tiredness, better concentration and lower absenteeism.
Nowadays, the need to keep indoor air quality under control is widely known due to the fact that people spend most of their time indoors. In order to show a useful working-tool this paper aims to present a guide to evaluate indoor air quality. This work was structured in the following stages: visual inspection, check list, data analysis, experimental measurements of the physical and chemical pollutants and an analysis of the improvement of indoor environmental quality.
Thermal sensation of tropically acclimatized subjects performing sedentary tasks under personalized ventilation (PV) was explored in this study. The study was conducted in an Indoor Air Quality (IAQ) chamber, which is capable of simulating typical office conditions in Singapore. An experimental design involving interventions in indoor ambient temperature, PV supply temperature and PV supply airflow rate, introduced blind to subjects, was conducted.
Experiments have been carried out to measure unsteady velocity fields near the coughing subject (mannequin) and also understand unsteady transport process resulting from this type of transient flow. Representative human cough waveforms were reproduced using a flow simulator and the measurements were made using Time Resolved Particle Image Velocimetry (TRPIV). Initial high velocity as well as rapid velocity decay with time and distance were observed, and velocity time history and vorticity variations were characterized.
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.
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