Potential and limits of Natural Ventilation for comfort in retrofit buildings in tropical climates

The space cooling demand is growing very fast in the world in conjunction with the increase of life standards and the climate change. A major stake for the future in buildings is to provide human comfort and to limit the cooling energy consumption. In this context, natural ventilation turns to be an interesting solution in tropical zones where 40% of the world's population lives. This paper aims to assess the potential and limitations of wind induced crossed natural ventilation for comfort in tropical environments. A method based on correlations from the literature is proposed, integrating all the links in the physical chain of natural ventilation, i.e. from outdoor climatic conditions to indoor comfort. The application of this method is done through a case study in Reunion Island and gives orders of magnitude of comfort time proportion according to different parameters such as the opening surface, the indoor thermal and humid loads and the orientation of the considered building. Finally, the limitations of the method are discussed, as well as the need for research to define design rules to favour natural ventilation for housing and office retrofit