The role of Life Cycle Assessment (LCA) and energy efficiency optimization during the early stage of building design

The environmental impact of buildings could not be minimized only by optimizing the operational energy since the reduction of operational energy frequently consumes more embodied energy due to the increase of materials and systems used for energy efficiency. Meanwhile, although LCA has been widely used to evaluate the environmental footprint, few studies explored its role in the early building design stage during which majority of the prominent decisions actually already have been made. This paper tries to offer a roadmap by incorporating LCA with energy optimization during the early design phase, to make LCA a more useful guidance tool for improving the design sustainability rather than a method only for the final verification. The workflow of integrating these two approaches is proposed. Several mainstream LCA software are compared and simplified LCA approaches are introduced for the implementation. In the same time, limitations related to this integrative work are also pointed out. For instance, the nature of design is a sequential processing work which fights against the demand of simulation software.