To date, around three quarters of all photovoltaic systems are on roofs, and a further quarter are on open spaces. The share of building-integrated systems (also called BIPV) is in the per mille range. Yet such systems have enormous advantages: In addition to electrical energy generation, BIPV also offers many of the functions of a classic facade, such as protection from wind and weather, shading or daylight utilization, with comparable quality. Regarding solar module technology, thin-film modules based on copper, indium, gallium and selenium (CIGS) offer the same aesthetic design possibilities as glass facades, since their cell structure is hardly visible, unlike in silicon photovoltaics, enabling homogeneous glass surfaces in subtle colors. This speaks in favor of facade PV - especially since it is necessary to exploit the entire PV generation potential in Germany as part of the energy turnaround.
As part of a research project led by ZSW, scientists are working with partners from research and industry to optimize CIGS thin-film photovoltaics for facade applications. In the process, both manufacturing technology and system technology issues are to be solved. Together with the industry and research partners, the overall system will be optimized by varying the module design in terms of energy yield, shade tolerance, ease of assembly and flexibility of module size and by adapting it to the other system components. In addition, the project participants are looking at the energy-economy potential of CIGS facade systems with regard to possible electrical and thermal energy coverage contributions at the building level.
The ZSW is responsible for design calculations, laboratory and field investigations at component and system level, and the collection of operating data. The comparative field tests of the different system variants with regard to function and yield are carried out on the Widderstall test field. The operating data of the CIGS facade systems test facade at the new ZSW institute building in Stuttgart are also included. These will also be used to calculate the energy-economy potential of CIGS facade systems.
