Fraunhofer Institute for Solar Energy Systems ISE| Duration: | January 2010 - December 2013 |
| Contracting Authority/ Sponsors: | German Federal Ministry of Education and Reserach (BMBF) |
| Project Partners: | Fraunhofer Center for Silicon Photovoltaics CSP; Technical University Dresden; Masdar PV GmbH; Solarion AG, Leipzig; MS SunStrom GmbH, Dresden; SMA Solar Technologie AG, Niestetal |
Solarvalley-BIPV – Operating Performance of Complex BIPV Systems with a-Si/μ-Si Modules
Fig.1 : Angle-selective PVShade® triple glazing units in the spandrel zone.
Fig. 2: Differently oriented, vertical a-Si/μ-Si modules at MasdarPV in Ichtershausen.
Fig. 3: Ratio of the DC power from the system in Ichtershausen for parallel-connected, east/west oriented, vertical module strings without:with separate MPP tracking; black – from measured DC power values, red – from simulated values, green – irradiance in the horizontal plane.
Within the ”Solarvalley-BIPV“ research project that was coordinated by Fraunhofer ISE, both novel BIPV components and also methods for detailed yield analyses were developed for building integrated photovoltaic systems (BIPV). In addition, high-quality measurement data sets were acquired for two grid-connected systems with a-Si/μ-Si modules. Comparison of the simulated results with measured data provides insights for BIPV component development and yield optimisation under typical BIPV conditions, such as higher module temperatures and differently oriented subsystems.
For the first time, the concept developed by Fraunhofer ISE for angle-selective PV glazing, PVShade®, was implemented in a BIPV pilot plant. Ten PVShade® triple glazing units with a total area of about 15 m2 were installed in the new building of Fraunhofer ISE in Freiburg. The angular selectivity is achieved by laminating two thin-film modules, which each feature an identical striped pattern, to each other with the stripes juxtaposed. The angle-selective configuration allows outward viewing and simultaneously provides solar control that varies with the season and time of day (Fig. 1).
For the yield simulation, the geometrically complex module configuration and shading by a neighbouring building wing were taken into account by ray-tracing calculations. The effect of high module temperatures and the interaction between the modules and the inverter were also modelled. The agreement between measured data from the scientific monitoring programme and simulated values for the DC current was very good, with an average difference of less than 3%.
The effect of connecting differently oriented module areas was investigated for a further a-Si/μ-Si system (Fig. 2). Both the measurements and the yield simulations for the year up to September 2013 resulted in an electric mismatch factor below 1% (Fig. 3). On this basis, the additional complexity of separate MPP tracking for each orientation is hardly justified for this type of system.