A comparative life cycle assessment between green walls and green facades in the Mediterranean continental climate

Abstract

The building and construction sector is a large contributor to anthropogenic greenhouse gas emissions and consumes vast natural resources. Improvements in this sector are of fundamental importance for national and global targets to combat climate change. In this context, vertical greenery systems (VGS) in buildings have become popular in urban areas to restore green space in cities and be an adaptation strategy for challenges such as climate change. However, only a small amount of knowledge is available on the different VGS environmental impacts. This paper discusses a comparative life cycle assessment (LCA) between a building with green walls, a building with green facades and a reference building without any greenery system in the continental Mediterranean climate. This life cycle assessment is carried according to ISO 14040/44 using ReCiPe and GWP indicators.Moreover, this study fills this gap by thoroughly tracking and quantifying all impacts in all phases of the building life cycle related to the manufacturing and construction stage, maintenance, use stage (operational energy use experimentally tested), and final disposal. The adopted functional unit is the square meter of the facade. Results showed that the operational stage had the highest impact contributing by up to 90% of the total environmental impacts during its 50 years life cycle. Moreover, when considering VGS, there is an annual reduction of about 1% in the environmental burdens. However, in summer, the reduction is almost 50%. Finally, if the use stage is excluded, the manufacturing and the maintenance stage are the most significant contributors, especially in the green wall system.