precast, CLT, SIP, GFRC, energy efficiency, condensation-moisture-rain-vapor, design processes, parametric workflows, computational design, academic/industry partnerships, pre-fabrication, climate, THERM, WUFI, HoneyBee
Facades developed in response to climactic factors increase performance and human comfort while reducing energy loads. A single building envelope will perform differently in different climates. Different assembly types perform differently from one another in a given climate. However, the time consuming process of evaluating the performance of a range of envelope options using multiple software programs is a significant hurdle, resulting in projects defaulting to regional traditions. A simple process for determining the most energy efficient assembly in any given climate is lacking. However, this process can be achieved by using a generalized computational design workflow that is platform agnostic. This research presents a generalized workflow designed to make climate oriented facade selection simple. With ASHRAE 189.1 as a basis for selecting R values for climates and assembly types, the performance of five facade systems are compared against each other in eight Climate Zones of North America. Facade systems compared include: glass-fiber reinforced concrete on metal frame, metal panel rain screen over cross laminated timber, exposed precast, and metal rain screen over structural insulated panel. For consistency, the facades are deployed onto a prototypical classroom building called ‘Sprout Space’, designed by Perkins+Will. The results indicate those assembly types that have the highest performance in each Climate Zone. The workflow developed for modeling (Rhino and Grasshopper) and analyzing the energy performance of the facade (WUFI, THERM and Honeybee) assemblies is explained. The influence of the building geometry on results is discussed. The influence of ASHRAE 189.1’s baseline R values on results is discussed. The ability to identify the highest thermal performance facade system within each climate. The workflow can enable facade consultants, engineers, and designers to understand the behavior of the different envelope types in each climate, leading to the selection of higher-performance facades.
Hypothesis: Computational tools can assist designers to automate the identification, analysis, and selection of prefabricated building envelopes based on climate-specific requirements.
The building envelope is a protective layer that separates
Various climate-specific design methods are being used by designers. CLIMATE ID (Van, 2009) and CROFT (Bilow, 2012) are concepts that suggest design solutions based on the climate. CROFT concepts are
The methodology uses Grasshopper to integrate multiple software programs to evaluate the performance of predesigned building envelopes in various climate contexts. The purpose of COPBE is to assist designers in
Energy Simulation of Sprout Space for All Climate Zones
The energy simulation for Sprout Space was done based on the constructions (32 type of assemblies) specific to the Climate
ASHRAE 189.1 minimum R-value requirements are fundamental assumptions of this research. By comparing assemblies meeting the minimum ASHRAE R-value requirements for each Climate Zone, the COPBE method compares apples to
In summary, a method for evaluating and ranking prefabricated envelopes for their performance in multiple Climate Zones is needed. Regional traditions and experience often dictate the assemblies used in the
The authors wish to thank the following people and institutions for reviewing, commenting, contributing and funding this research:
USC Committee: Professor Joon Ho Choi, Professor Douglas E. Noble
Perkins+Will Technical Committee: Bill Schmalz, Paul Allen, Eric Brossy de Dios, Aleks Janjic, Alex Minard, Merv Burtnett, Henry De Jesus, Bertrand Piquet
Perkins+Will Researchers: Santiago Diaz, Tyrone Marshall, John Haymaker, Anton Szilasi
Clark Pacific Commenters: Matt Katz, Dima Franchuk
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All images by the authors.