The Influence of Operating Temperature on the Performance of BIPV Modules

Abstract

To investigate the effect of the operating temperature on the performance of building integrated photovoltaic modules, two different crystalline silicon (c-Si) module types (glass/backsheet and glass/glass) with two different mounting configurations (ventilated and insulated) were installed in Canobbio, Switzerland and monitored over more than four years outdoors. The differences in the performance loss rates (PLRs) between module types and mounting configurations were determined by using the year-over-year methodology. The glass/backsheet module was markedly affected by the higher operating temperature: PLR changed from 0.01%/yr for ventilated to -0.42%/yr for insulated. However, the glass/glass module showed an opposite and unexpected trend: PLR changed from -0.10%/yr for ventilated to 0.26%/yr for insulated. Analysis of the IV curve parameters revealed that the decreased performance of the insulated glass/backsheet module was chiefly due to the loss in the fill factor with increased resistance; however, the gain in the short-circuit current (I-sc) was the main driver for the increased performance of the insulated glass/glass module. Real-world temperature coefficients were further examined and they were mostly found to be in line with the values measured indoors. Lower power-temperature and higher current-temperature dependence of the insulated glass/glass module, compared to the ventilated construction, supported the observed performance and current behavior of this module.