BIM-based investigation of total energy consumption in delivering buildings as a product

Considerable efforts have been made to reduce buildings' operational energy use over the last decades, but little attention has been paid to reduce the material, transportation and construction energy. Focusing only on the operation phase forgoes the opportunity to reduce other building-related energy consumption, and even if the environmental impacts arising from construction and transportation are small as compared to the operation phases, its cumulative impact at the national level is of concern. Assessment of the energy associated with the material production, transportation and construction of buildings provides an opportunity for reducing the use of energy and improving sustainability. Building Information Modeling (BIM) provides a platform to incorporate sustainability information in the design of buildings. However, interoperability of BIM with Life Cycle Assessment (LCA) tools needs further investigation. Previous research in this area has either partially employed BIM; data was exported from the main BIM authoring tool and then auxiliary tools were utilized to evaluate the model, thereby causing a disconnect between the model and analysis resulting in non-interoperable systems, or has ignored the importance of retaining the LCA results within the BIM environment. To address this issue, this study presents a framework to estimate the embodied energy content within the BIM environment. The implementation of this framework is illustrated by the development of a tool for estimation of material embodied energy, transportation energy and construction energy. Simulation models are created, which can be used as templates for energy optimization during transportation and construction. By analyzing different resource combination scenarios, lower energy consumption can be achieved. The presence of embodied energy results gives way to the potential of sensitivity analysis to optimize the embodied energy content. Therefore, there is a need for a formal and standard definition of embodied energy content in BIM. Such inclusion is necessary to perform related model sharing through main stream BIM data exchange protocols such as Industry Foundation Classes (IFC). Therefore, this study also proposes an extension of the IFC model to incorporate embodied energy information. Matching the aspects of cost associated with the building elements and processes, a new resource of energy is proposed. Consequently, the abstraction of this energy resource is further embedded by establishing the relationship with other model entities. A prototype tool has been implemented on a case project to establish the workability of the framework.