The potential of liquid-based spectrally-selective optical filtration and its use in hybrid photovoltaic/thermal solar systems

The overheating of photovoltaic (PV) cells in various PV systems has been a serious problem that academics and academicians have spent many hours trying to solve. Optical Filtration is a revolutionary method that has been created to address the issue of overheating as well as the drawbacks of directly exposing PV cells to the entire spectrum of solar light. The study sheds light on recent research on liquid-based optical filtering. Installing liquid optical filtration in front of the panel can improve electrical performance. It provides more control over the incident solar-radiation spectrum as well as increased heat absorption through the filtration fluid. The incident radiation is filtered for both conventional PV and PVT systems to improve thermal control. The electrical and thermal performance of the filtering fluid was of critical importance. Due to the restricted variety of fundamental fluid properties, nanofluids were offered as an alternative. It was lauded for its capacity to regulate the optical and thermal properties of basefluids. More power was produced at lower nanomaterial loadings and diameters, as well as lower filtration optical lengths. Thermally, nanofluid filtration was more efficient, but its transmittance and electrical output were lower than that of basefluid filtration. Among several basefluids, deionized water was the best for filtration due to high transmittance and heat extraction. On the other side, the water/core–shell silver-silicon oxide (water/Ag-SiO₂) nanofluid presented a high agreement with the efficient spectral range of the PV cells. Due to the high thermal viability of liquid-based optical filtering employing nanofluids, handling overheated cells was a challenging task. Low transmittance and solar energy received by the panel may be offset by excessive side-cooling of PV cells. In high sun intensities, optical filtration was required to protect the panels.