Survey of the existing approaches to assess and design natural ventilation and need for further developments

In the last years many building designers have turned their attention to natural ventilation, due to the potential benefits in terms of energy consumption related to ventilation and air-conditioning, especially in mild and moderate climates. Consequently, several calculation techniques have been developed to design and predict the performance of natural ventilation.  This article presents a review of the existing approaches to predict natural ventilation performance, including simple empirical models, nodal models (mono-zone and multi-zones), zonal models and CFD models. For each approach, we analyse the physical basis, the main modelling assumptions, the necessary input data and the area of applicability. Thus, the integration of these methodologies in the available simulation programs is examined, with reference to the different phases of the natural ventilation design process and some examples of application are given. The aim of the review is to identify the main practical limits of existing programs in designing natural ventilation and in predicting its performance and the consequent need for further developments.