Optimizing Shading and Thermal Performances of Vertical Green Wall on Buildings in a Hot Arid Region

Abstract

Due to global concerns about energy issues, global warming, and urban quality, vertical greening systems (VGS) are receiving more attention in construction and design research. Therefore, VGS has become part of building envelope design as a passive technique for saving energy in building sectors. The current study aimed to investigate shading and energy performances of VGS in buildings in hot climate regions and to optimize VGS design as a building design element. The study was conducted through simulation and field experiments in a student housing building at a university campus (Irbid, Jordan). Field measurements were taken to assess the thermal effect of the green wall and daylight performance as well as the efficiency of the typical green wall design configura-tion. Furthermore, a methodology for accurately representing green walls was established and used. Both simulation and experimentation demonstrated that the thickness of the air cavity and the per-centage of foliage coverage can have a substantial impact on the performance of the green wall sys-tem. Results showed that green wall systems are effective natural sunscreens and shading systems. A green wall helped to reduce the exterior wall surface temperatures by a range of 6 to 11 °C compared to the base case of the wall without a VGS on different days. In addition, it decreased the interior surface temperature of the investigated southern façade by an average of 5 °C compared to the base case. Green wall design configurations for hot climate regions, such as Jordan, will help designers to use the VGS as a design element. Our findings indicate that GW could help to improve the thermal and daylight environment and thus the results could be taken as indicative for GW wall design in other areas or buildings.