Assessment of the effects of environmental factors on air flow in and around buildings

This paper assesses air flow characteristics in and around buildings under different environmental conditions using computational fluid dynamics modeling techniques. It argues that any "generic" representation of air flow without explicitly stating the quantification of the parameters assumed in deriving those representations (as commonly encountered in architectural design guides or similar publications), may be erroneous and should be used with caution. To illustrate this point, an experimental approach is adopted to select certain air flow phenomena or design guidelines offered in some "representative" publications where the environmental context may not have been explicitly communicated in qualitative and quantitative terms. Demonstrative sets of quantitative values are then applied to the relevant design input parameters within certain assumed environmental context to simulate the air flow performance using an air flow modeling tool CFD-ACE+ (2000). The results from the parametric experimental set-ups demonstrate that any change in the environmental factors can significantly affect the boundary conditions and consequently the indoor air flow in both velocity and distribution pattern. It reinforces the main assertion of this work that it is critical for the building design team to clearly define the performance goals of the project as well as the contextual conditions, covering both the qualitative and the quantitative aspects as comprehensively as possible. This will facilitate a productive design process that will yield clear and accountable solutions accordingly.