An analysis to understand how the shape of a concrete residential building influences its embodied energy and embodied carbon

Abstract

The built environment is recognized as a major hotspot of resource use and environmental impacts. Life Cycle Assessment (LCA) has been increasingly used to assess the environmental impacts of construction products and buildings and a new trend is characterized by the application of LCA to larger systems such as neighborhoods during early design phases. Assessing urban development projects at the master-planning stage raises the issue of inventory data collection, especially for building materials which are reported to account for about 20% of primary energy consumption in buildings, and up to 45% of associated greenhouse gas emissions. Urban planners focus on the urban morphology and little information is known about the buildings characteristics apart from their general shape. This paper proposes a simplified model for the assessment of buildings embodied energy and embodied carbon in relation with urban planners’ design levers. The model relies on the decomposition of buildings into functional elements in order to be sensitive to the shape of the buildings. A detailed sensitivity analysis and contribution analysis of the model is conducted on two types of generic building forms, in order to investigate the influence of parameters relating to shape on the embodied energy and embodied carbon of a building. The sensitivity analysis shows that the parameters relating to shape (such as the dimension of the buildings) are more influential on the embodied energy and embodied carbon per square meter of building than the ones relating to the elements themselves (such as the wall thickness). The contribution analysis also brings evidence of the relation between the compactness factor and the embodied energy and embodied carbon of a building.