Cornell University’s College of Architecture, Art, and Planning hosts the annual Robert James Eidlitz Travel Fellowships competition. Established by Sadie Boulton Eidlitz in 1938, these awards are intended to assist recipients in supplementing their professional education through travel study. This year, my proposal titled SkinNY was chosen by the Eidlitz committee. SkinNY is an investigation of double skin facades. Its aim is to assess the enclosure strategy by profiling the environmental context, system design, and occupant experience of existing structures.
SkinNY was prompted by a project that challenged facade consultants to propose highly efficient skin systems to meet Passivhaus standards for the recladding of an education complex in upstate New York. The double skin facade stood out as a strong sustainable option for its climate-sensitive thermal performance and reuse of existing materials. Yet, when compared to alternative enclosure systems, the double skin facade performance did not warrant its cost or complex systems integration.
Double skin facades have been acclaimed for their optimization of daylight, acoustics, thermal comfort, and energy use. By encasing an air corridor between two glass skins, the double skin facade creates a buffer zone between the external and internal environments. Ideally, the buffer zone prevents interior temperature fluctuation, thereby reducing heating and cooling loads and improving the overall energy efficiency of the building. The success of a double skin facade is very much dependent on climate and integrated building systems. Without proper consideration of these factors, a double skin facade will not live up to its green reputation.
The first double skin facade was implemented in 1903 for the German Steiff Factory to “maximize daylighting while taking into account the cold weather and strong winds of the region” (Poirazis). Today, double skin facades are common in Europe due to high energy costs. However, there are only approximately 16 double skin facades in the US (Vaglio). The acceptance of double skin facades has been slow in the US for a number of reasons, including:
1) the absence of consultants in the early phases of design
2) the cost of initial implementation of double skin facades
3) the traditional segregation of trades
4) the absence of an engineering discipline responsible for shading systems
5) the low healthy work environment standards
Interdisciplinary communication in the initial design phase is critical to the prediction of building energy consumption and the selection of appropriate facade strategy. The key factors to evaluate building energy consumption are location, function, and climate, which are all typically available in the initial design phase (Vaglio).
The initial implementation of double skin facades is more costly than conventional facades, however building life-cycle costs may justify this early investment. The evaluation of post-occupancy performance, in particular energy consumption, maintenance, and occupant experience, can predict a structure’s cost of operations over its entire life (Aksamija). Moreover, this information can be used to assess facade strategies and improve future designs.
SkinNY intends to study German examples of double skin facades to gain insight on how US designers can overcome the above mentioned obstacles, with particular emphasis on early phase integrated design and life-cycle cost assessment. The two week travel proposal includes visits to three cities Frankfurt, Dusseldorf, and Berlin, with the intention to review double skin facade precedents, meet with facade consultants, and visit glass manufacturing facilities.
The proposal will produce a detailed case study for each precedent by collecting onsite documentation and comparing these findings to post-trip analysis models. Onsite documentation will include facade system and daylighting photographs, site analysis, and occupant experience surveys. This information will be used to produce two distinct sets of analysis models. The first will model the thermal performance of facade systems using Therm, a conduction heat-transfer analysis based on the finite-element method. The second will model annual daylight and glare of a typical interior space using Honeybee/Ladybug, an environmental analysis plugin that connects Grasshopper with RADIANCE and Daysim energy simulation engines.
The onsite documentation will be paired with the post-trip analysis on a SkinNY website. This digital catalogue will combine case study data with occupant experience to assess double skin facade strategies. Moreover, the SkinNY website will speculate on how US practices can learn from specific German examples and will provide tutorials for designers to study basic thermal and daylighting analysis methods.
Harris Poirazis, “Double Skin Facades: A Literature Review” from IEA SHC (2006).
Jeff Vaglio, Mic Patterson, Stacey Hooper, “Emerging Applications and Trends of Double-Skin Facades” from Enclos Insight 01 (2010).
Jeff Vaglio, Mic Patterson, “Seeing Double” from Enclos Insight 02 (2012).
Ajla Aksamija, Ph.D., “Context Based Design of Double Skin Facades: Climatic considerations during the design process” from Perkins+Will Research Journal Volume 01.01 (2009).