Adopting an integrated building energy simulation and life cycle assessment framework for the optimisation of facades and fenestration in building envelopes

Abstract

Delivering sustainability in the buildings and construction sector requires innovation in the materials used and tools adopted to help promote low-carbon, zero-energy and resource-efficient buildings. This study has proposed an integrated building energy simulation (BES) and life cycle assessment (LCA) framework to inform the selection of sustainable facades and fenestration for a building. The influence of distinct facade systems, enhanced glazing options and varying window-to-wall (WWR) ratios are examined for a theoretical office nearly zero-energy building (NZEB) located in a temperate maritime climate. The embodied and operational environmental impacts – carbon, energy and resources – are quantified and compared for each facade system. The results presented an 8.3% reduction in operational energy demands with enhanced glazing yet translated to a 10% increase in the embodied impacts; equating to an additional 7.0–7.6 months towards the cumulative environmental payback. The optimal conditions for combined heating and cooling performance in the building was a 0.2 variable WWR layout. This can reduce the total energy consumption by 2% or 4.8 kWh/m2/year when compared to equivalent uniform WWR configurations. The proposed integrated BES-LCA framework provides guidance for NZEB facade and fenestration assessment, demonstrating the value of quantitative environmental assessments of building components during the design process. Further framework enhancements can ensure additional life cycle considerations are accounted for, such as circularity, life cycle costing and geospatial considerations.