IAM Losses in Colored BIPV: From the Lab to the Field

The aesthetic challenge in deploying building-integrated photovoltaics (BIPV) is addressed by exploring coloration solutions, particularly absorptive materials. These, aside from the direct coloration losses, also introduce additional absorption and reflection losses, which increase with the incidence angle and vary significantly depending on the color. In this study, BIPV modules with colored interlayer foils are investigated, revealing significant differences in incidence angle modifier (IAM) behavior between the five colors studied. The Martin and Ruiz model captures the overall trend but faces difficulties in fitting the IAM of colored samples, especially when combined with satinated or structured glass. In contrast, the polynomial Sandia IAM model achieves a solid fit. Furthermore, this study compares the lab-determined angular optical losses with outdoor measurement data. This involves modeling effective irradiance and power output, accounting for color-dependent module efficiency, temperature effects, and IAM losses. The study also indicates that apart from IAM losses, spectral mismatch variation has a significant effect on the performance of colored BIPV.