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Optimization for structural performance and energy usage in conceptual building design

A traditional goal of structural optimization has always been material reduction, which can lower both the cost and embodied energy of a design. However, when structural optimization is applied to buildings, the relationship between embodied energy of the structure and operational energy of the building is often ignored. In many cases there are clear tradeoffs between the two that can be seen even in conceptual design. In order to use optimization methods to explore the trade-offs between structure and energy usage, a translation and conversion must take place between the “sticks” analyzed by structural software and the “surfaces” analyzed by energy modeling software. Once this translation has been made, it is possible to explore different conceptual designs with reference to their structural and energy usage performance. It is also possible to scale the structural performance score by embodied energy to understand the relative importance of these different design objectives in term of a single unit – emissions.

In this talk, we will present a number of case studies in which a conceptual architectural design is optimized with the multiple objectives of structural efficiency and minimized operational energy usage. The designs are first developed and parameterized using the geometric drawing software preferred by architects, and then analyzed by FEM and energy simulation programs that easily plug into this design environment. In a multiple-objective optimization problem in an architectural context, important tradeoffs occur and designers may exhibit preferences in different areas. For this reason, the rapid generation and evaluation of conceptual design alternatives in terms of both structure and operational energy gives the designer an opportunity to optimize towards a diverse range of high performing solutions. These case studies suggest a more generalized process for pursuing multiple-objective optimization in conceptual building design, which lays the groundwork for a potentially valuable tool for architectural and structural designers.

Author(s):

Nathan Brown    
Massachusetts Institute of Technology
United States

Caitlin Mueller    
Massachusetts Institute of Technology
United States