ABSTRACT This article discusses energy-efficient retrofitting design strategies for commercial office buildings, and examines their effect on energy consumption. The objective of the research was to study how to integrate passive design strategies and energy-efficient building systems to improve building performance, and reduce the energy consumption of existing buildings in three different climate types (cold, mixed and hot climates). First, properties of existing buildings were analyzed based on national CBECS database to determine typical characteristics of office buildings located in Chicago, Baltimore and Phoenix, including size, building envelope treatment and building systems. Then, fourteen different prototypes were developed, varying the building shape and orientation to represent different building stock, and energy modeling was conducted to establish energy usage baseline. Multiple design considerations were investigated based on extensive energy simulations and modeling, where low-impact and d...

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.

AbstractThis research article discusses methods for designing high-performance facades with a focus on minimizing heat transfer and improving energy usage. The facade is one of the most significant contributors to the energy budget and comfort parameters of any building. Control of physical environmental factors, including methods for minimizing heat transfer, must be considered during the design process. High-performance facades need to block adverse external environmental effects and maintain internal comfort conditions with minimal energy consumption. The research was conducted by initially modelling conductive heat transfer in four different exterior wall types, including a brick cavity wall, a rain-screen facade with terracotta cladding, a rain-screen facade with glass fiber–reinforced concrete cladding, and a curtain wall, to compare their relative thermal performances. Then, heat-transfer modelling was conducted for three thermally improved systems, including curtain walls with thermally broken fra...

This article discusses results of a research study that investigated daylight performance of glazed double-skin facades (DSFs) in various climate types. The objectives of the study were: 1) to analyze the daylight levels in different types of DSFs (box window, corridor type, and multistory) in four different climates; 2) to compare daylight performance against the conventional single skin glazed facade (curtain wall); 3) to investigate the effects of facade orientations on daylight; and 4) to investigate the impacts of facade characteristics (different depth of air cavities in DSFs) on daylight levels. The research methods consisted of daylight simulations in Radiance software program of an office space, which would be enclosed by the investigated facade types. Multiple models were developed to investigate different typologies of DSFs, depth of air cavity between the two skins, orientations and climate types, as well as sky conditions, totaling a dataset of 336 simulation models. Daylight simulations were performed for sunny, overcast and cloudy sky conditions, for four different locations (Miami, San Francisco, Chicago and Duluth). Results indicate that all types of DSFs would decrease daylight levels compared to a conventional curtain wall; however, the air cavity depth and DSF facade type have a significant impact on the daylighting performance. Moreover, the results show that the discrepancies are largest in the area closest to the glazed facade. The article presents detailed results and discusses the effects of each variable on daylight levels. Author

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 two-dimensional 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 32°C, 16°C, -1°C and -18°C). 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 three types of DSFs influence airflow in the air cavity. Lastly, energy modeling was conducted for south-oriented 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. 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.

Today’s design professionals are faced with challenges on all fronts. They need not only to keep in step with rapid technological changes and the current revolution in design and construction processes, but to lead the industry. This means actively seeking to innovate through design research, raising the bar in building performance and adopting advanced technologies in their practice. In a constant drive to improve design processes and services, how is it possible to implement innovations? And, moreover, to assimilate them in such a way that design, methods and technologies remain fully integrated?