Thermal, Energy and Daylight Analysis of Different Types of Double Skin Facades in Various Climates

Abstract

This article explores thermal, energy and daylighting performance of double skin facades (DSFs) in different climate types, specifically focusing on three typologies: box window, corridor and multi-story DSFs.  These systems were investigated and analyzed to determine how different DSFs perform in comparison to each other, as well as a typical curtain wall (single skin glazed facade used as a baseline), in a multitude of climate applications. The utilized research methods included two-dimensional heat transfer analysis (Finite Element Method analysis), Computational Fluid Dynamics (CFD) analysis, energy modeling, and daylight simulations. Heat transfer analysis was used to determine heat transfer coefficients (U-values) of all analyzed facade types, as well as temperature gradients through the facades for four exterior environmental conditions. CFD analysis investigated three-dimensional heat flow, airflow and air velocity within air cavity of DSFs. Energy modeling and daylight simulations were conducted for an office space, which was enclosed by the analyzed facade types. Individual energy models were developed for each facade type and for fifteen different climates representing various climate zones and subzones, from very hot to arctic. For daylighting simulations, multiple models were developed to study investigated typologies of DSFs, depth of air cavity between the two skins, orientations and four climate types, as well as different sky conditions. Results indicate that there is not a lot of variation in thermal performance of the different DSF types, but that all DSF facades would have significantly improved thermal performance compared to the baseline single skin facade. Energy modeling results indicate significant differences in performance between the DSFs and single skin facade, but fewer variations between the different typologies of investigated DSFs. Moreover, the results show the effect of DSFs in different climate types on energy performance, heating, cooling and lighting loads. Daylighting results indicate that all types of DSFs would decrease daylight levels compared to a conventional curtain wall, however, the differences between lighting levels are also dependent on the orientation, air cavity depth, facade type and climate.