EFFECTIVENESS AND EFFICIENCY OF VENTILATION SYSTEM IN EASTLINK

Abstract

Individual units in EASTLink utilized mixing ventilation system to supply fresh air into the environment and it was found that this form of ventilation strategy is ineffective and inefficient in providing a good indoor environment to the occupants where there is an increase in the concentration of carbon monoxide (CO) and temperature over a 1 hour period, with presence of high relative humidity and low wind speed registered in an unit as well. Even though the concentration of CO is well within the emission limits from Code of Practice on Pollution Control administered by National Environment Agency (NEA), the existing ventilation system is calculated to be only 37.5% efficient when compared to CP 13: Code of Practice for Mechanical Ventilation and Air-Conditioning in Buildings. Hence, this brings out the importance to predict ventilation performance of the building during the design stage through the use of Computational Fluids Dynamics (CFD). A base model was generated using CFD software Gambit and Fluent 6.3 to represent the actual conditions onsite and the converged base model is validated against field measurements to determine its accuracy. 7 CFD models with different ventilation strategies are proposed with the aim to reduce the concentration of CO in the unit effectively and efficiently while keeping parameters defined in the base model constant so as to evaluate and determine the optimal ventilation strategy. From the 7 models, it was discovered that the best model requires the possession of certain characteristics such as there must be no presence of negative pressure in the unit coupled with effective dilution of the concentration of CO, as well as efficient reduction in the concentration of CO when air is drawn out of the unit from high pressured to low pressured areas.