Vertical Greening Systems and Urban Heat Island related aspects: outcomes of a research project

Vegetation in architecture can be assumed as a proper design strategy aimed at improving climate in cities and towns. Vertical Greening Systems (VGSs) and green roof are both building systems introduced extensively in recent times in architecture design. The interest about such systems is remarkable and it is often due to both their physics and environmental performances. A variety of ecological benefits can be ascribed to VGSs, i.e. heat island effect mitigation, noise abatement, heating and cooling energy demand reduction, absorption of particulate matters as well as of VOC, enhancement of biodiversity. Furthermore a noteworthy contribution is given towards those aspects related to extreme weather events affecting nowadays European cities, such as heat-waves and urban flooding. Within an industrial research project, focused on the design, manufacture and performance assessment of a VGS, a number of environmental issues were tackled in. The study was aimed, on one hand, identifying a methodology to select materials to be used in the module assembly and, on the other hand, at testing its performance during actual operating use. In this paper results are presented concerning the aspects related to UHI at the mere building envelope scale, as the assessment of the CO2 equivalent emissions due to manufacturing processes, the analysis of VGS thermal behavior and of its potential in reducing the wall external surface temperatures. These experimental results will constitute the starting point for a research activity aimed at evaluating, through the use of simulation tools, the UHI mitigation at building and urban scale