Green wall design approach towards energy performance and indoor comfort improvement: A case study in Athens

In the 21st century, sustainable development is high on the international agenda, with the implementation of green walls contributing significantly to achieving environmental and social benefits, mainly in the frame of sustainable improvement of the building sector. The installation of a greening system can provide engineered solutions for stormwater management and climate change mitigation at both the urban and building level. This facilitates improving indoor comfort conditions and reducing energy needs. In order to improve the features of products and to facilitate the implementation of a proper technical standard, this paper proposes a critical bibliographic analysis of more recent scientific works. Moreover, by means of a numerical model of an existing single-family apartment, placed in the Mediterranean climate zone, a building envelope refurbishment with a living wall is carried out. A parametric analysis provides evidence for the application of different plants' types and insulation materials. The results are analyzed considering the energy needs, the thermo-hygrometric comfort, and the outdoor surface temperature variation of the building envelope, emphasizing that a multi-criteria design approach is needed for green vertical systems. The paper provides data and an approach useful for designers and researchers in the evaluation and optimization of the performance of greening systems.