This research article discusses the methods for designing sustainable, high-performance facades, and the necessary steps in ensuring that the environmental factors and energy-efficiency strategies are integrated with the design process. The facade is one of the most significant contributors to the energy budget and the comfort parameters of any building. Control of physical environmental factors must be considered during the design process, as well as design strategies which improve occupants' comfort. High-performance facades need to block adverse external environmental effects and maintain internal comfort conditions with minimum energy consumption, and the location and climate become one of the crucial factors in selecting appropriate design strategies. The article discusses climate-based approaches for designing high-performance facades, characteristics and properties of sustainable facade systems, tools and building performance analysis steps that can assist during the design process, as well as a case study that illustrates how these approaches have been implemented on a real architectural project.

The facade is one of the most significant contributors to the energy budget and the comfort parameters of any building. Control of environmental factors must be considered during the design process. High-performance facades need to block adverse external environmental effects and maintain internal comfort conditions with minimum energy consumption. The purpose of this research was to analyze thermal behavior and energy performance of different facade types, as well as impacts of climate change on facade performance. The study was conducted by modelling conductive heat transfer in seven different exterior wall types, considering conventional and thermally improved opaque and glazed systems. Conventional facade systems included brick cavity wall, rainscreen facade with terracotta cladding, rainscreen facade with glass-fiber reinforced concrete cladding and a conventional curtain wall, while thermally improved systems included rainscreen facade with thermal spaces, rainscreen facade with thermal isolators and a curtain wall with thermally broken framing. Heat transfer and thermal gradients through these systems for four exterior environmental conditions were simulated, considering outside temperatures of 90°F, 60°F, 30°F and 0°F. Also, heat transfer coefficients (U-values) were calculated and compared to determine thermal performance. Impacts on energy use were also investigated, where energy usage was modeled for an office space enclosed with the analyzed facade types for all U.S. climate zones and 12 orientations, and for window-to-wall ratio of 20 and 40 percent, using historical weather data. The results show relative performance of analyzed exterior wall types, in terms of thermal performance and energy usage. Then, future climate conditions were considered, where the impacts of climate change on changing weather patterns were investigated. Specifically, predicated climate change weather files for the years 2050 and 2080 were used to model energy usage for the office space enclosed with analyzed exterior wall types. The results show the impacts of climate change on the energy performance, and show that the energy usage is increased for all investigated wall types and in almost all climates.

This paper explores thermal and energy performance of double skin facades (DSFs) in different climate types, specifically focusing on three typologies: box window, corridor type and multistory DSFs. These systems were investigated and analyzed to answer the question of how the different DSFs perform in comparison to each other, as well as a typical curtain wall (single skin facade used as a baseline), in a multitude of climate applications. The utilized research methods included twodimensional heat transfer analysis (finite element analysis), Computational Fluid Dynamics (CFD) analysis and energy modeling. 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 (exterior temperatures of 90°F, 60°F, 30°F and 0°F). Results indicate that there is little 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. Then, CFD analysis investigated three dimensional heat flow, airflow and air velocity within air cavity of DSFs. Results indicate that the differences between the different types of DSFs influence airflow in the air cavity. Lastly, energy modeling was conducted for an office space, which would be enclosed by the analyzed facade types. Individual energy models were developed for each facade type and for 15 different climates, representing various climate zones and subzones in the U.S. The results were analyzed to compare energy performance of DSFs and baseline single skin facade, as well performance of DSFs in various climate types. The results indicate significant differences between the DSFs and single skin facade, but less variations between the different typologies of investigated DSFs. Moreover, the results show what would be the effect of DSFs in different climate types on energy performance, heating and cooling loads.

ABSTRACT Developments in information technology are providing methods to improve current design practices, where uncertainties about various design elements can be simulated and studied from the de...