Review of Natural Ventilation Models

Abstract

Natural ventilation (NV) is an important and efficient passive technique to reduce building cooling energy need and improve indoor air quality. NV design requires profound knowledge and accurate prediction of air flow and heat transfer in and around buildings. This paper reviews the important NV models and simulation tools and the comparisons of their prediction capabilities. In one hand, a review of the analytical models reveals that these models are generally only applicable to specific geometries and driving forces. In other hand, results of comparison and assessment between airflow models have shown that the current one can be used to model most NV mechanisms, with an exception of wind-driven single-sided ventilation. For the predictable cases, the most accuracy is achieved for cases with small and simple openings. For larger openings and especially complicated openings, the model's predictions are less accurate. Furthermore, the model is heavily dependent on several somewhat ambiguous coefficients including: wind profile exponent, pressure coefficient, and discharge coefficient.