Life cycle assessment of buildings and city quarters comparing demolition and reconstruction with refurbishment

Abstract

In the building sector, the energy and the greenhouse gases embodied in the building materials are becoming increasingly important. Combined with the operational primary energy demand and the end-of-life, the whole life cycle of buildings can be assessed.In this paper, a comprehensive method for calculating the life cycle of individual buildings is presented. First, their material composition has been determined and generic values for the embodied energy, embodied greenhouse gases, energy needed and greenhouse gases emitted during disposal of the different building materials have been calculated. Subsequently these values have been integrated into an urban energy simulation software to simulate energy and emission values for buildings.A given building geometry with four different building standards was considered. The results can help to decide between building refurbishment or demolition and new construction. For example it could be shown that the share of the life cycle stage production compared to the total value rises with a better building insulation standard, as the share of the use stage decreases. The highest building refurbishment standard resulted in the best life cycle performance when compared with less ambitious refurbishment or construction of a new building of today’s standards.