Photovoltaic/thermal (PV/T) systems hold great promise for integrated solar energy harvesting, as they simultaneously generate electricity and useful heat. While numerous theoretical and numerical studies have explored nanofluid-based PV/T enhancements, there is a lack of experimental investigations that systematically compare the energy and exergy performance of mono-, binary-, and ternary-component nanofluids under identical operating conditions. This work addresses this gap by presenting the first comprehensive experimental evaluation of water-based nanofluids—including GO, TiO2, Fe3O4, their binary combinations, and a ternary GO/TiO2/Fe3O4 blend—in a sheet-and-serpentine-tube PV/T collector tested under a controlled solar simulator. Mass flow rates (20–80 kg/h) and nanoparticle concentrations (0–1 %) were systematically varied. Results reveal that the ternary nanofluid consistently achieves the highest overall performance, reaching maximum energy and exergy efficiencies of 89.95 % and 15.36 %, respectively-exceeding the best binary formulation by 2.50 % (energy) and 0.38 % (exergy), and outperforming the leading mono-component by 4.86 % and 1.23 %. These findings provide experimental validation of the synergistic thermophysical advantages of ternary nanofluids, offering practical guidelines and new benchmarks for designing high-efficiency PV/T systems.
