Unsteady wind effects can be important in natural ventilation, but their treatment requires knowledge of instantaneous surface pressure distributions which are extremely difficult to obtain. The paper describes a theoretical investigation aimed at determining the effects of unsteadiness and, perhaps more important, the conditions for which it may be worth accounting for them in the design process. For generality the study uses nondimensional parameters. The effects of unsteadiness on both mean and instantaneous flow rates are covered.
Several models have been developed to study the airflow pattern and thermal distribution in buildings. This paper describes the development of a zonal model that may be incorporated into existing building energy analysis programs. The modeling is detailed in three applications describing how such a model can be simply applied. The model predictions were then compared with measurements and/or Computational Fluid Dynamics (CFD) model prediction.
The wind and buoyancy pressure driving forces for natural ventilation of buildings are very low, typically less than 10 Pa. Depending upon the prevailing climatic and thermal conditions, or even the location of a building on a site in relation to other surrounding buildings and landscape, the predominant pressure force incident on a purpose-provided natural ventilation opening can either be closer to the lower range of pressure differentials (< 2 Pa) or vary over a wider range of higher pressures (2 - 10 Pa).
Ventilation is one of the most important measures to dilute indoor air pollutants. In order to maintain a clean indoor air environment, not only the total ventilation rate of the building but also the distribution of outdoor air to each area must be taken into consideration. A performance evaluation of various ventilation systems, which have different air supply and exhaust equipment, has been made. This investigation was undertaken over a heating period, in a full-scale test house.
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