Performance of nanofluid-based photovoltaic/thermal systems: A review

Recently, applying nanofluids in PV/T systems for improving the performance of these systems has been fascinating many researchers. In this kind of research, nanofluids are employed in the PV/T systems as coolant or optical filter. To emphasis the capability of the nanofluids in PV/T systems, the present study aims first, to comprehensively review the features, structures, and the outcomes of PV/T system that applied nanofluids and investigated the effectiveness of nanofluids, and second, to comprehensively analyze the effective parameters on the performance of a nanofluid-based flat plate photovoltaic/thermal system in both laminar and turbulent regime. In this study, with respect to literature, a vast attempt has been done to study the effects of nanofluids parameters including volume fraction (0-4%), size (21 nm and 100 nm) and type of nanoparticles (TiO2 and Al2O3), as well as type of base fluid (water and mixture of ethylene glycol-water). The accuracy of proposed mathematical model was demonstrated through the comparison of predicted results and the available data in the literature. It can be concluded from the results that, to improve the performance of the system, adding nanoparticles is more efficient in laminar regime compared to turbulent one. The results also indicated that using nanoparticles of larger diameter leads to greater total energy and exergy efficiency in the turbulent regime, while contrary behavior is observed in laminar flow. Moreover, it was observed that employing aluminum oxide in nanofluids improves the system performance more than titanium oxide, where water based nanofluids show higher energy and exergy efficiency compared to ethylene glycol-water based nanofluids.