Case study assessment for natural ventilation performance of heritage buildings in the Mediterranean city of Alexandria (Egypt)

Historic buildings are an important aspect of any city in their capacity to provide cultural reference points. Demonstrating capacity for better levels of energy efficiency and thermal comfort has become a critical challenge to such buildings’ survival. Wind driven natural ventilation in buildings is one way of reducing energy use by dependence on mechanical ventilation. This paper is a case study assessment of a nineteenth-century listed residential building located in the historic business district of the Mediterranean city of Alexandria (Egypt). From an architectural perspective, the European style courtyarded building offers good potential for healthy indoor air replacement, and the Mediterranean climate of the city provides enhanced possibilities for promoting indoor thermal comfort. Yet observation of the building today demonstrates that occupants rely heavily on mechanical ventilation (air conditioning) . It is clear that the building’s original layout has been modified. In this research, we use 3D RANS CFD simulation to investigate the potential for the original layout of the building to enable natural air flow patterns. Simulations are validated against air speed measurements in parts of the building. The results show a detailed natural ventilation deficiency performance in the case study building as modified today, and indicate potential for future improvement. This investigation can help in the understanding of conservation approaches that not only preserve the building’s cultural value but also reclaim its natural ventilation performance.