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Vertical Facade Integration of Bifacial PV Modules: Outdoor Testing & Optical Modelling
B. Soria, E. Gerritsen
Bifacial, Ray Tracing, Outdoor, Facade, Module Architecture
Subtopic: PV Modules
Event: 28th European Photovoltaic Solar Energy Conference and Exhibition
Session: 4AV.5.19
3216 - 3221
ISBN: 3-936338-33-7
Paper DOI: 10.4229/28thEUPVSEC2013-4AV.5.19
0,00 EUR
Document(s): paper, poster


Bifacial modules integrated in a double skin vertical façade have been studied using a reduced scale test bench and a ray-tracing model. The influence of opto-geometrical parameters (double skin distance, reflector, and apertures) as well as that of the module architecture (electrical and optical) is reported. We found good agreement between experimental and simulated data for both sunny and cloudy days (R²>96.6%). The optimal distance and maximum bifacial gain compared to a monofacial reference are comprised between +18% and +20% for distances between 0.5h and 0.75h (h being the height of the module). In the optimal configuration the bifacial module temperature is found to be lower than the monofacial temperature, up to -2°C at 1 sun. For shorter distances the non-uniformity of backside irradiance limits the module electrical output. For this case we tested a module architecture which uses half-cell strings connected in parallel. Compared to a standard module we obtained a gain up to 4% in a 36° tilted south orientation (front only) which is attributed to lower resistive losses. However the small scale test bench did not allow to get experimental evidence of this structure being beneficial under non-uniform backside irradiance. We also evaluated glass with a unidirectional surface texture on front and backside of a module. This type of glass texture showed a 3% gain in a 36° south configuration by improved harvesting of low solar angles and diffuse background radiation. On our vertical façade test bench the textured glass gave a gain between +4% and +6%, originating mainly from the frontside.