Life cycle assessment approach for the optimization of sustainable building envelopes: An application on solar wall systems

Design of sustainable building envelopes requires the analysis of environmental performances in every stage of their life cycle. As a matter of fact, the production phase of building materials and components can significantly contribute to the total energy consumption and environmental loads of buildings. However, façade systems such as passive solar systems, ventilated walls and double skins, are usually not designed considering aspects related to their life cycle. Furthermore, there are still few studies concerning the optimization and the combined effect of different design features of complex façades on environmental and energy performances. This paper introduces an integrated approach for the optimization of energy and environmental performances of complex building envelopes that combines life cycle assessment, energy simulation and optimization analysis with factorial plan technique. The environmental performance was calculated in terms of energy demand and CO2 emissions in the production phase and operational phase. The methodology was applied to an exemplary case study with solar wall systems. The results showed that solar walls have high environmental impact both in the production and operational phases. Results of the optimization analysis demonstrated that it is possible to reduce the CO2 emissions and cumulative energy demand of solar walls for both the production and use phases up to 55% in comparison with a traditional design. This methodology may be generally applied to the sustainability analysis, design and optimization of efficient façade systems.