Ceiling-Mounted Personalized Ventilators Effectiveness in Reducing the Spread of Particles in Office Spaces

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Now-a-daysNowadays offices are becoming more crowded with occupants with short distances separating stations, which increase the probability of respiratory cross-infection between workers via two different paths. One path is transmission through air resulting in direct inhalation of contaminant and the other path is through body contact of contaminated surfaces of furniture and walls. Significant relationship was shown to exist between particle pollution and people’s mortality and morbidity due to increase of risks of cardiovascular diseases, lung cancer and other health problems as asthma and a variety of respiration diseases. For this reason, multi-stations offices should be carefully designed to prevent cross-contamination between the occupants by both the direct and indirect paths while insuring thermal comfort. However, such solutions need to be implemented with consideration of efficient use of the space by minimizing the distance between the occupants and proper selection of an energy efficient system. Therefore, the challenge is to propose a practical energy efficient air distribution system that will prevent direct and indirect cross contamination between workstations when placed close to each other. The aim of this work is to come up with a simple localized/personalized air conditioning system for crowded offices. The performance of three ventilation systems will be considered. These systems are: 1) Single personalized ventilation (PV) nozzle added to ceiling diffuser; 2) Single PV nozzle aided with desk fan; and 3) Coaxial PV nozzle integrated with a peripheral ceiling diffuser. These systems’ effectiveness will be assessed with respect to preventing the spread of particle matter and reducing not only the inhaled fractions but also the number of deposited particles on surfaces in the proximity of the occupant. The energy saving will be quantified when compared to conventional system. The systems will be compared in order to come up with recommendations that could be implemented in the design and applications of personalized ventilation systems which would lead to improved air quality and reduced risk of cross-contamination in office buildings.