A study of different envelope scenarios towards low carbon high-rise buildings in the Mediterranean climate - can DSF be part of the solution?

The numbers of high-rise buildings around the world increase rapidly. However, this fast pace is not in tandem with the expertise gained on how to design this building typology to best adjust it to local climates. In addition, the increased transparency of the building envelope from the mid-twentieth century onwards, resulted in high-energy loads, especially prominent in high-rise construction. With planning policies moving towards targets for low carbon built environments, this challenging typology needs further research and experimentation. This study focuses on the building envelope, as a passive design strategy towards reduced energy loads. Simulations of different envelope scenarios in the Mediterranean climate are conducted with EnergyPlus thermal simulation engine, and comparisons are made on energy loads in relation to height. Initial simulations between three single-skin envelope scenarios and a ventilated double skin façade (DSF) revealed the importance of lowering the high cooling loads relevant to the hot and humid climate, while external shading performed better from a double-skin envelope with LowE glazing as the interior layer. The focus then shifted on increasing the energy efficiency of the DSF, as a more advanced envelope option (controlled ventilation, acoustic insulation etc.), by drawing comparisons between four DSFs. Simulations showed that the most energy efficient DSF in the Mediterranean climate is with LowE glazing as the outside layer. In the final step, the comparison between the building envelope with the proposed DSF and the one with external shading was in favour of the DSF option. Conclusions are drawn on the relationship of the building envelope with climate, with a preference on DSF towards a low carbon building design, while suggestions are made for further DSF research.