Experimental evaluation of a newly designed photovoltaic thermal collector featuring a ring inserter as a flow enhancement mechanism

The ongoing inefficiencies in collector designs continue to pose a major challenge in advancing photovoltaic thermal (PVT) systems. To address this, a newly designed collector featuring circular inner tubes and perforated ring inserts was introduced. The indoor experiments were performed under controlled conditions, with a solar simulator providing consistent irradiance and water employed as the working fluid. The tests were conducted over varying mass flow rates of 0.01–0.06 kg/s and under solar irradiance levels ranging between 250 and 1000 W/m 2 . Optimal performance was achieved at an irradiance of 750 W/m 2 with a flow rate of 0.06 kg/s. Under these conditions, the system attained a maximum thermal efficiency of 77.379% and the highest electrical efficiency of 11.48%. Compared to a conventional smooth tube PVT system, the new design demonstrated a significant 17.25% increase in electrical energy efficiency, primarily due to improved cell temperature regulation. The system also reached a maximum power output of 25.19 W under the optimal conditions. • Mass flow rate and solar irradiance strongly affected PVT performance, lowering cell temperature and alteringthermal/electrical responses; the novel tube produced the largest cell-temperature drop (21.29 °C at 1000 W/m 2 ). • The new perforated-ring PVT consistently exceeded the smooth-tube thermal performance: 71.97% vs 65.35% at 250 W/m 2 , peaking at 77.38% (750 W/m 2 ). • Electrical efficiency improved for the new design under all conditions, with a maximum gain of 20.37% at 750 W/m 2 and 0.06 kg/s due to better thermal regulation. • The highest measured power output was 25.19 W when using the newly designed tube, confirming its superior cooling and energy-conversion capability.