DSF studies towards energy efficiency for a tall building design in the Mediterranean climate

Abstract

Tall buildings around the world are increasing at an accelerating pace. However, this fast-pace development is not in tandem with today’s environmental considerations towards reducing high carbon emissions, mainly relating to the building sector (close to 50% of carbon dioxide (CO2) emissions). The vast scale and energy demands of tall buildings call for an in-depth study of this building typology towards improving energy efficiency. An important consideration for lowering energy demands is the configuration of the building envelope that acts as the mediator between indoor and outdoor conditions, according to the climate and microclimate of the building’s location. Current architectural practices of fully glazed curtain wall envelopes make this relationship problematic, by resulting in high-energy loads for achieving thermal comfort. Over the last few years, a step forward towards energy efficiency is the use of a double-skin façade (DSF). Its application, however, is lacking consideration of the specific climatic conditions that will essentially result in an energy efficient design. Previous research revealed that the most energy efficient DSF in the Mediterranean climate is with LowE glazing as the outside DSF layer. Further studies on DSF cavity width for a hot climate, were in favour of wider cavities, as these reduce the high cooling loads that are associated with this climate. Additionally, simulations of an office building in the Mediterranean climate, confirmed that cooling energy is also present during winter (airtight DSF), suggesting for a more active DSF envelope design throughout the year. A further study is then conducted through simulations, where the DSF design alternates between an open / closed DSF, and comparisons are made in relation to DSF width, building height above ground, outdoor environmental conditions and interior thermal comfort, for further improving the energy efficiency of tall building design.