Efficient structural roof form as a tool for energy savings in building design

Opportunities for increasing energy-efficiency in the built environment may be found by dividing the energy consumed by buildings into three life-cycle phases: the Pre-use phase (embodied energy), Use phase (operational energy), and Post-use phase (demolition, re-use, or recycling). Today it is well known that as operational energy use is reduced, the relative importance of embodied energy becomes more apparent. Within the initial embodied energy of a building, the structural system can be the major component. Currently, reinforced concrete frame technologies constitute a standard structural system commonly employed in low-rise buildings.. This ongoing study, conducted in a seismically active desert region, examines the potential life-cycle energy savings that may be achieved by the exploitation of alternative structural roof forms, which by carrying their loads efficiently may greatly reduce the reliance on cement and reinforcing steel, both of which contribute to the high energy-intensity of typical building structures. A complex energy-based optimization framework is proposed, using computational tools for design, analysis and prediction. The objective is to minimize the use of high-embodied-energy building materials and their effect on the whole life-cycle energy consumption, while satisfying mandatory national building code performance requirements for structural reliability and serviceability. The analysis of optional designs takes into consideration the particular characteristics of the local area – such as climatic considerations, transportation distances, seismic risk, etc. Hence, the optimization method proposed integrates a number of techniques: a form-finding process which includes structural analysis, a thermal simulation, and a life-cycle energy assessment (LCEA) evaluation over a 50-year life span. The method may serve as a decision support means from the early schematic phases of environmentally-responsible building design.