Development of coupled facade technologies based on green roof and hybrid facade elements for integration into AI-supported building energy concepts (GreenQ)

To meet these requirements, this project aims to develop multifunctional facade elements with integrated green roofs or coupled glass-on-glass photovoltaic systems to support the building’s heating and cooling needs. On the one hand, green roofs can help mitigate climate change, as green buildings require less energy for indoor climate control and thus emit less CO₂. On the other hand, green roofs are a measure for adapting to ongoing climate change, as they help reduce temperatures inside the building and in outdoor areas during heat waves, thereby improving living conditions for people.

The physical effects of green roofs examined in the project are:

1. Cooling through evaporation of water from the plant surfaces and the substrate in which the plants grow
2. Shading provided by the plants
3. Increase in the building’s heat capacity
4. Reduction in heat loss from the building due to lower convection coefficients at the building’s surface

These effects are being investigated by HSWT as part of the project. Direct measurements for the assessment of the influence of green roofs on indoor temperatures are difficult, as it is generally not possible to find multiple identical buildings that differ only in the presence or absence of a green roof for measurement purposes. For this reason, measurements are being conducted on test buildings (see Figure 1). Parameters related to the aforementioned physical effects are being determined from these measurements and laboratory studies. A physical model for building greening is being developed, in which the determined parameters are used to conduct an assessment of the impact of greening on realistic residential buildings via a software tool created from this model. With the help of the developed software tool, green roof systems will then be designed for real buildings.

The following points will be addressed:

1. Adaptation of existing test rigs and new laboratory experiments to investigate greening elements, including those on facades and in combination with irrigation systems
2. Development of a physical model for roof and facade greening elements in combination with irrigation systems
3. Determination of model parameters through test bench measurements and laboratory experiments, as well as the development and validation of a calculation tool
4. Thermal design of the greening elements and the control strategy for irrigation and hydraulics using the developed calculation tool
5. Assessment of the measurement data by project partners

Particular attention is being paid to the development of irrigation strategies for the greening systems. The cooling capacity of the greening systems depends on the type of irrigation. Furthermore, the study examines how the cooling capacity can be optimally distributed throughout buildings via connected hydraulic systems (heat exchangers).

In addition to Weihenstephan-Triesdorf University of Applied Sciences (HSWT), the following institutions and companies are participating in the project:

• Bauhaus University Weimar
• eft-system GmbH
• Flachglas Sülzfeld GmbH
• Adaptis Technologies Canada Inc.
• ZinCo GmbH