The ability to accurately predict air movement and temperature distribution in spaces offers the potential for design engineers to evaluate and optimise room air distribution systems at an early stage, leading to improved thermal comfort and ventilation effectiveness. The computer models which are used for detailed analyses are based on computational fluid dynamics [1,2] and employ sophisticated numerical algorithms to satisfy the basic laws of physics. The programs are such that they are more complex and more difficult to use than those with which design engineers may be more familiar.
Mechanical ventilation system performance involves the provision of adequate amounts of outdoor air, uniform distribution of ventilation air within the occupied space, and the maintenance of thermal comfort. Standardized measurement techniques exist to evaluate thermal comfort and air exchange rates in mechanically ventilated buildings; field techniques to evaluate air distribution or ventilation effectiveness are still being developed. This paper presents field measurements of air exchange rates and ventilation effectiveness in an officepibra-y building in Washington, DC.
Reviews definitions of ventilation efficiency and outlines physical concepts, measurement methods and calculation techniques. Includes bibliographic list of author affiliations.
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