Evaluation of PV module designs at irregular operation conditions

Building integrated PV systems are interesting due to a double use of PV modules as facade or roof elements though PV facades suffer often from the effect of partial shading. Usual strategies apply bypass diodes for solar cell protection. This however requires unwelcome and costly centre taps of the strings to a junction box at large area PV facade modules. The choice of a suitable protection scheme demands information regarding the effects of irregular operating conditions like shading. This contribution shows the influence of PV module design regarding thermal effects at partial shading without bypass diodes. Current module designs in glass/glass technique do not allow renunciation of bypass diodes. Modified designs regarding cell connectors or rear back covers could make it possible to work without bypass diodes and with that to simplify electrical module layout with such "Hot Spot resistant" facade modules.