Values for total dust concentration in indoor air in day-care centres, offices and schools with no reported problems are measured. These are: day-care centres 41 14 g/m3, offices 16 5 g/m3, schools 20 10 g/m3. In parallel the particle size distribution in six interval from 0.3 m - >20 m are reported. No seasonal variation in total dust concentration could be seen. Sudden increase in number of the particles in the smallest intervals are found at night for some systems when they are shut down or working on reduced speed.
This paper gives the results of a field study in Danish office spaces with displacement ventilation systems. Draught was identified as a serious problem. Half of the 227 occupants were not satisfied with indoor air quality. Occupants counteract draught discomfort in blocking air supply diffusers or asking the maintenance staff to increase the supply air temperature. So a very careful design for displacement ventilation is required in order to perform satisfactorily in practice.
Prediction of airflow and pollutant transfers in a simple multizone building may use different approaches such as zonal or nodal modeling methods. This paper proposes to improve the modeling of pollutant transport by coupling nodal and zonal models in the SPARK simulation environment.
Nodal model gives mass airflow rates used as boundary conditions in the zonal model to predict pollutants mass transport. Simulation results are compared with experimental data from the 2 zones testing room Minibat.
Variations in heat source positions in a room bring changes in the ventilation effectiveness. Those changes are studied using experimental data and CFD results. Results show that a good ventilation effectiveness can be achieved when the contaminant and the heat source are located close to the zone containing the exhaust opening.
The concentration of fungal spores is higher in the crawl space than inside houses. Domestic mechanical exhaust ventilation systems may create air flow between crawl space and base floor through leaks. This study used data from eight buildings to develop a model providing relation between indoor and crawl space fungal spores concentrations. Results show that the correlation between the fungal spores in the crawl spaces and indoors depends on the size range of microbe species.
In an air-conditioned office building in Singapore, 3 different filtration systems have been evaluated under similar fresh air intake and ventilation rate conditions (electrostatic filtration, electrostatic filtration with chemical adsorption, and media filtration) . Chemical and microbial contamination levels under different filtration strategies have been monitored.
This paper describes a method for the determination of optimal indoor conditions, using three parameter indexes: PMV (predicted mean vote) for thermal comfort, CO2 concentration for indoor air quality and cooling/heating load for efficient use of energy. A performance index of the HVAC system is calculating by adding square errors between actual and desired values. It is then minimized to find optimal indoor air conditions.
This paper deals with the simulation of air flow pattern in an office in Singapore (22.5 m x 84 m) with a typical day environmental conditions. Thermal comfort and indoor air quality audit, as well as ventilation measurements are used for validation of the simulation results.
Provision of good IAQ in buildings located close to a busy road requires application of air filtration systems which are efficient for submicrometer and especially ultra fine particles, since traffic emissions are associated with particles in these size ranges. A study has been conducted in which a filtration system of an office building was designed according to measured outdoor air conditions and theoretically predicted indoor air conditions. The performance of the system was then validated by field measurements of particle concentration levels indoors and outdoors.
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