Studies on the optimum double-skin curtain wall design for high-rise buildings in the Mediterranean climate

The fast growing numbers of high-rise buildings around the world, a product of expanding urbanization and population growth, dictate the implementation of design strategies towards the reduction of their high energy loads. This study focuses on an office high-rise building in the Mediterranean climate of Tel Aviv and the reduction of high cooling loads relevant to this climate. In this process, the design of the building envelope becomes the most important constituent between indoor and outdoor environment, by dictating the required use of energy for achieving thermal comfort. A double skin façade (DSF) layer is proposed as a more advanced envelope design compared to the single skin curtain walls (controlled ventilation, acoustic insulation etc.). A previous study based on thermal simulations in Tel Aviv, revealed that a ventilated DSF design with the LowE glazing as the exterior layer of the DSF reduced cooling loads by 15% on average, in comparison with a typical DSF design in temperate climates where the LowE glazing is on the interior layer of the DSF, and by an average of 50% from the option of single skin envelope with LowE glazing. This study draws from the conclusions of previous data, and tests the energy efficiency of different DSF cavities in the Mediterranean climate. Results revealed that by increasing the cavity width from 0.2 m to 0.5 m, cooling loads decrease significantly, while there are also substantial reductions, from 0.5 m to 1.0 m, and from 1.0 m to 2.0 m DSF cavity width.