The impact of optical liquid filters on PV panel performance

The goal of this research is to investigate the effect of utilizing selective liquids as absorption filters to prevent PV module overheating by blocking the undesirable part of the spectrum (long wavelength) while allowing the beneficial part of the spectrum (visible light and near infrared) to pass through. The fluids were evaluated on two different panels, and their results were compared to those of a control panel. In this work, two liquids were used and tested: copper sulfate solution (CuSO₄·5H₂O) and distilled water as absorption filter; each was arranged in such a way that it flows evenly over the surface of a PV module through a cavity mounted on the top side of the PV module. In addition, a standard PV panel was employed as a comparison. The average power produced by the PV when pure was used as an optical filter is 31.3%, while it was 11.3% when copper sulfate solution was used compared with base unit. Furthermore, the cooling effect of pure water on the PV was more efficient than that of copper sulfate solution, with an average PV temperature drop of 15% compared with 7.5% when copper sulfate is used compared with the base unit panel's performance improved by an average of 31.3% when distilled water was used as the absorption filter, compared to the reference panel's performance, while the copper sulfate solution improved the panel's performance by an average of 11.3% compared to the reference panel's performance.