MARGRET Bioshade – Quantification of Shading and Cooling Performance Provided by Building-Integrated Greening

MARGRET Bioshade focuses on the scientifically robust quantification of the effects of building-integrated greening systems as a measure for climate change adaptation. Green roofs and façades can reduce urban heat island effects, positively influence the urban water balance, and decrease heat gains in buildings and the surrounding urban environment. Despite their growing relevance, reliable and standardised performance indicators are still largely lacking. Quantifying dynamic, plant-based systems is particularly challenging compared to static, conventional building components, especially due to the required establishment and growth phase and the associated changes in performance over time.

Building on the highly instrumented test infrastructure established in the predecessor project MARGRET, MARGRET Bioshade directly addresses these research gaps. The project aims to develop transferable performance indicators for planning, simulation and standardisation. The shading performance of vertical greening systems in front of window surfaces is systematically quantified and compared with conventional shading devices using parameters such as transmittance and g-values. In addition, the water balance and energetic effects of different roof and façade greening systems are analysed, with a particular focus on runoff behaviour during heavy rainfall events, reduced heat gains and evaporative cooling.

Measurements are conducted on five vertical greening systems as well as on test rigs with intensive and extensive green roofs at an advanced growth stage. Innovative measurement and characterisation methods are applied, including area-based solar transmittance measurements using pyroscanners, camera-based transmittance analyses, water balance assessment methods, and standardised plant characterisation (e.g. wall leaf area index and coverage ratio). A digital twin with real-time data visualisation supports data evaluation and comparability.
The project is expected to deliver reproducible, seasonally differentiated indicators for the energetic and hydrological performance of building-integrated greening systems, providing a solid basis for integrating green infrastructure into energy performance certificates, guidelines and simulation models.