FPSC performance has remained low despite technical developments. Innovatively constructing solar energy collecting systems to maximize efficiency needs more investigation. This study examines the thermal performance of a flat-plate solar energy harvesting system using a cutting-edge collector design and hybrid nanofluid. A spiral tube collector (STC) is designed as a single flow tube by replacing the header-connected riser tubes in a parallel tube collector (PTC). By modifying the collector's design, a noteworthy enhancement in thermal performance was achieved. STC's experimental testing shows 18.98%, 28.86%, and 18.97% enhancement in thermal efficiency, exergy efficiency, and energy gains compared to PTC design. STC design reduces pressure drop by 6.25% and entropy generation by 28.86%. The current investigation may help choose an appropriate collector design for efficient solar energy harvesting purposes.