Experimental comparison of the electrical efficiency of photovoltaics and photovoltaics-thermal hybrid system in real operation conditions

This study presents an experimental investigation of the electrical performance of a conventional photovoltaic (PV) panel and a photovoltaic–thermal (PVT) hybrid system under real meteorological conditions in Bosnia and Herzegovina. The impact of varying water mass flow rates (0.017–0.067 kg/s) through a carbon steel heat exchanger on the PVT panel temperature, electrical efficiency, power output, thermal efficiency, and thermal energy storage (TES) was analyzed, with ambient temperature, solar irradiance, and wind speed recorded throughout the experiments. Experiments conducted in July demonstrated that the PVT system consistently maintained lower operating temperatures (maximum 48.86 °C) compared to the reference PV panel (maximum 61.22 °C), resulting in improved electrical efficiency and reduced temperature-related losses. The PVT system exhibited higher electrical efficiency than the reference PV panel, with efficiency improvements ranging from 4.2 % at the lowest mass flow rate (0.017 kg/s) to 7.1 % at the highest flow rate (0.067 kg/s). At this highest flow rate, the PVT system achieved its best overall performance, with an electrical efficiency of 16.21 %, an average electrical power output of 73.01 W, a daily TES temperature rise of 6.6 °C, and a thermal efficiency of 41.46 %. These results confirm that enhanced heat removal directly supports improved photovoltaic performance and demonstrate that appropriate thermal management enables simultaneous improvement of electrical and thermal energy conversion, highlighting the potential of low-cost carbon steel heat exchangers for practical and efficient PVT operation under real operating conditions.