Systemic implementation of Vertical Greenery Systems

Climate adaptation of cities is one of the most pressing current problems in light of increasingly frequent extreme events such as heat waves, droughts, and heavy rainfall. At the same time, climate adaptation must be in line with the decarbonization of the building sector, which is to be achieved in the European Union by 2050. Technological end-of-pipe solutions are widely used but, in turn, often have negative impacts on the climate themselves when their entire life cycle is considered. Vertical Greenery Systems (VGS) are recognized as climate adaptation measures that can strengthen climate resilience, while providing a carbon sink. Due to their low horizontal space requirement, they are particularly suitable for implementation in densely built-up areas. Although empirical studies provide information on the thermal impacts and water requirements of VGS, there is a need for process-based, standardized assessment methods that can be applied to different locations, building morphologies, and VGS designs. This thesis aims to provide transferable process-based calculation methods for (1) the required irrigation water, (2) recycling potentials using alternative irrigation water sources (i.e., rainwater and greywater), and (3) potentials in cooling energy reduction on the building level for ground-based VGS. First, a model adaptation concept for the daily reference evapotranspiration of a VGS was developed. The most relevant meteorological parameters were identified and adapted to the micro-climatic conditions at a specific urban site. The model’s performance was evaluated using onsite measured meteorological and lysimeter data. We found the best predictions of VGS water demand when meteorolgical input data is verticalized, i.e., adapted to the facade and height-adapted. While using daily data leads to robust results, further research is needed for hourly resolution. Using the verticalized evapotranspiration approach, the water recycling potential of VGS for alternative water sources (i.e., rainwater and greywater) for six case study buildings differing in their climatic conditions, architecture, and occupancy has been evaluated. VGS was found to be a suitable water recycling measure. The water management potential depends on climatic factors but can be overruled by the building features determining greenable areas and the provision of alternative water sources. We found quarter- or district-based planning should be preferred over planning for single buildings. Finally, assuming sufficient water supply, the cooling energy-saving potential of VGS in the existing building stock has been quantified. Therefore, relevant building types in Berlin, Germany, and Ljubljana, Slovenia, have been identified. Thermal effects and cooling energy savings during summer have been calculated using a process-based one-dimensional heat-mass-transfer model. Findings suggest VGS is most effective for walls with moderate insulation (U-values) and low thermal inertia. Suitability of VGS for cooling should be quantified dynamically and case-specifically. The presented thesis provides transferable, process-based methods and analyses to evaluate VGS as an interface in the water cycle and urban energy balance. It is thus contributing to evidence-based planning of VGS for urban water management and energy efficiency and fostering climate resilience in cities.

Author dc:creator

• Hoffmann, Karin

Advisor dc:contributor.advisor

• Paton, Eva

Licence dc:rights.uri

• https://creativecommons.org/licenses/by-nc-nd/4.0/

Language dc:language.iso

en

Identifier URI

https://doi.org/10.14279/depositonce-22396

OAI identifier oai:identifier

oai:depositonce.tu-berlin.de:11303/23582