Researchers Analyze the Impact of Texturized Glass on Building-Integrated Photovoltaics

Researchers from Poland have evaluated the effects of texturized glass, used as the front cover for building-integrated photovoltaic (BIPV) panels, on their performance. Their findings indicate that power yield could be up to 5% lower compared to modules made with conventional glass, with reflection parameters reaching as high as 88% in the visible spectrum.

A team from the John Paul II Catholic University of Lublin conducted an analysis of the optical and electrical properties of texturized glass in BIPV systems, revealing that such glass significantly influences photovoltaic power generation and increases light reflection.

“In urban installations, low reflectance is crucial to reduce glare that can blind drivers,” explained lead author Paweł Kwaśnicki. “As BIPV becomes more popular, especially for facades, walls, and various types of glazing, aesthetic aspects are increasingly important.”

Textured glass is produced by heating glass sheets, softening them, and then passing them between engraved rollers. For this study, the researchers used two commercially available textured glass sheets. The first sample featured a surface topography with height differences of 45 μm and a regular pattern with features measuring 400 μm in diameter. The second sample had a height variation of 10 μm with an irregular pattern, containing objects ranging from 50 μm to over 1 mm.

Three modules were constructed for the analysis: one with sample 1, another with sample 2, and a third with standard clear glass as a reference. A lamination foil was placed between the glass and the cell, which had a measured power output of 2.89 W. The fill factor of the bare cell was recorded at 71%, with an open-circuit voltage of 0.699 V and a short-circuit current of 5.83 A.

The researchers noted, “The solar direct absorptance for the reference sample was almost 13 times lower than that of sample 1 and 5 times lower than that of sample 2.” Both textured samples exhibited significantly lower transmittance in the near-infrared (NIR) region compared to the reference glass. Additionally, sample 1 showed slightly lower transmittance in the infrared (IR) region compared to sample 2. In the visible light (VIS) spectrum, sample 1 demonstrated an 8.5-fold lower reflection, while sample 2 showed a 1.6-fold reduction.

Regarding electrical performance, the reference cell achieved a maximum power output of 2.86 W, while sample 1 produced 2.79 W and sample 2 yielded 2.74 W. The fill factor, open-circuit voltage, and short-circuit current for the reference module were 72.4%, 0.73 V, and 5.425 A, respectively. For sample 1, these figures were 72.9%, 0.727 V, and 5.27 A, and for sample 2, they were 73.2%, 0.728 V, and 5.143 A.

The analysis concluded that power yield in modules utilizing texturized glass could be up to 5% lower than in those using conventional glass, with reflection parameters reaching up to 88% in the VIS region. “As infrared radiation can negatively impact silicon photovoltaic cells—limiting energy absorption, causing thermal effects that reduce efficiency, and leading to optical losses due to carrier recombination—using textured glass in PV modules is advantageous,” the researchers stated. They also noted that prolonged exposure to IR radiation can accelerate material degradation, affecting the stability and lifespan of PV modules.

These findings were published in the article “Texturized Glass in the Application of Architectural Photovoltaics” in Cleaner Engineering and Technology. In addition to the John Paul II Catholic University of Lublin, Kwaśnicki is associated with Polish PV supplier ML System.