The parabolic trough collector (PTC) is one of the most advanced solar concentrating technology available. The study employed experimental synthesis and numerical modeling to present possible solutions to the challenges of nanofluids application in solar collectors. A green alternative of using nanoparticles synthesized from green biomatter (Olive leaf extract OLE) and agricultural waste (barley husk BH) is proposed. The synthesized nanoparticles were characterized using analytical and morphological techniques and were found to be efficient corrosion inhibitor, non-toxic and cheap to produce when compared to the conventional ones. The study presents an innovative thermal performance evaluation of a parabolic trough collector operating with green-synthesized nanofluids: water/BH-SiO2 and water/OLE-TiO2. The model of the PTC was developed on the engineering equation solver (EES) and validated using the experimental results of the Sandia National Laboratory (SNL), AZTRAK platform LS-2 test. The results of the analysis show that a 0.073% mean enhancement in the thermal efficiency is observed with the use of water/BH-SiO2 nanofluids and 0.077% mean enhancement with the use of water/OLE-TiO2 nanofluids. The heat transfer performance of the nanofluids shows a mean enhancement in heat transfer coefficient of 128% and 138% for water/OLE-TiO2 and water/BH-SiO2 nanofluids respectively. The mean variation in pressure losses between the nanofluids and base fluid was also observed to be less than 14.85% at a 3% volumetric fraction of nanoparticles.