A comparative study for improving indoor air quality between two types of supply air diffusers at different occupants density.

The need of a clean indoor environment has received a lot of attention in recent years as a result of the rise of diseases and viruses around the world, and acceptable indoor air quality and maximum thermal comfort are particularly essential markers of passenger comfort. This research focuses on resolving indoor air quality (IAQ) issues in office environments, as well as analysing the principle of the influence of occupant density under mixing ventilation on office room thermal comfort. Two office rooms were simulated under a mixing ventilation system using the program ANSYS 15.0 (ICEPAK). The relative humidity, air temperature distribution, carbon dioxide concentration (CO2) and thermal efficiency were numerically estimated for each room and a comparison was made between the two rooms to show the effect of the diffuser type on the comfort of the occupants. Three tests were conducted for each room, depending on the number of persons in the room (3,4,6 persons). The air supply temperature and flow rate of the two rooms differ according to the heat acquired from the external environment, where the air temperature and flow rate (19.8 oC) and (0.45 m3/s), respectively, were recorded in the office room (under-linear slot diffuser), while in the office room (under-round ceiling diffuser) were the air supply temperature and flow rate (16 oC) and (0.1766 m3/s), respectively. The results of the tests found that the indicators of thermal comfort (ADPI), (PPD), (PMV) improves with reducing the number of person in the room. When comparing the two rooms, the results show that the office room (under-round ceiling diffuser) gives better indicators of thermal comfort than the office room (under-linear slot diffuser). In the present office area, the air distribution efficiency of the (MV) system using round ceiling diffuser was an average of (10%) greater than a similar system utilizing linear slot diffuser; this disparity reduces by around (2%) with each increase in the number of persons. [ABSTRACT FROM AUTHOR]