Fraunhofer Institute for Electron BeamThe DesignPV project, funded by the Federal Ministry for Economic Affairs and Energy as part of the 7th Energy Research Program, aims to advance building-integrated photovoltaics (BIPV) through innovative technologies and appealing design. The focus is on developing cost-effective, durable, and visually appealing solutions to harness previously unused façade areas for energy generation.
A key aspect of the project is the integration of decorative films onto both PV-active and non-active façade elements to enable a uniform appearance. The decorative films are based on ETFE substrate films, which are already well-established in architectural applications due to their excellent weather resistance. However, because ETFE's low surface energy makes it difficult to apply decorative layers, Fraunhofer FEP developed a plasma process that roughens the films on a nanometer scale, significantly improving the adhesion of those layers.
The decorative films are patterned using roll-to-roll nanoimprint lithography (NIL). This process enables the large-area patterning of films with feature sizes ranging from a few nanometers to millimeters. In this process, a patterned master roller is pressed into a coating layer while the coating is simultaneously cross-linked by electron beam irradiation. This continuous technology allows for highly productive manufacturing with web widths of up to 1,250 mm and process speeds of up to 100 meters per minute. In addition, it allows for the integration of pigments and particles to create surfaces that closely replicate the tactile and visual properties of natural materials.
Initial Results
At the project’s midpoint, several decorative patterns were initially applied to PET films and successfully installed and tested on both PV-active and non-active façade elements. The results show that the decorated PV modules are visually almost indistinguishable from conventional façade elements and – depending on the decorative pattern – achieve an output of up to 80% of that of the uncoated reference modules. This represents significant progress, as aesthetic considerations are often seen as a barrier to the acceptance of BIPV solutions.
Outlook
In the next step, the results obtained will be transferred to ETFE substrate films. In addition, testing of further decorative patterns and color variations, as well as comprehensive investigations into long-term stability and weather resistance, are planned. The goal is to further increase the integration of BIPV in architecture and to make the technology usable for the energy-efficient retrofitting of existing buildings.
With DesignPV, Fraunhofer FEP is making a significant contribution to the energy transition and to the sustainable design of urban spaces.
Project Partners
FLACHGLAS Sachsen GmbH
Fraunhofer Institute for Electron Beam and Plasma Technology FEP
Institute for Solar Energy Research GmbH Hamelin
Ronge GmbH
SURTECO GmbH
TOMASIC Engineering GmbH
