Photovoltaic–thermal (PVT) collectors often experience limited heat extraction under laminar cooling conditions, and the influence of controlled flow pulsation on full-scale PVT performance has not been clearly established. This study experimentally investigates a water-cooled PVT system operated under pulsating flow using an indoor solar simulator to quantify its thermal and electrical response. Flow pulsations were generated using a solenoid valve at frequencies of 0.25, 0.5, 1, and 2 Hz across inlet flow rates of 1–4 L/min, with average irradiance maintained between 700 and 800 W/m². System performance was benchmarked against uncooled and continuous-flow reference cases. Pulsating operation reduced the PVT surface temperature and produced a clear enhancement in thermal performance relative to continuous flow, while electrical efficiency exhibited a smaller but consistent improvement that followed the same thermal trend. A pulsation frequency of 0.5 Hz yielded the most favorable results, achieving thermal efficiencies exceeding 50% at higher flow rates without any measurable increase in average pressure drop. Electrical efficiency stabilized at approximately 9.82%, slightly higher than that obtained under continuous-flow operation. The results indicate that low-frequency pulsating flow can significantly improve thermal energy extraction in PVT systems under controlled conditions, with modest associated electrical gains, and provide a basis for further investigation of flow-modulation strategies for thermally driven PVT applications.