Experimental investigation of an innovative water-based photovoltaic/thermal module in moderate climate of Cracow, Poland

Renewable energy sources in energy production have become imperative as the world transitions toward a greener future. The growing demand for sustainable and efficient energy has led to the emergence of photovoltaic/thermal systems as a promising approach to enhance solar energy utilization. These hybrid systems simultaneously convert solar energy into electrical and thermal energy offering advantages over stand-alone photovoltaic and solar-thermal systems. However, many photovoltaic/thermal system designs reported in the literature suffer from complex structures, low efficiencies, and limited practicality for real-world deployment. This paper proposes a novel water-based photovoltaic/thermal module that integrates a highly efficient cooling system with a photovoltaic module. An experimental analysis of the proposed system was conducted in a town located 60 km from Cracow, Poland. The outdoor experiments showed that at an inlet mass flow rate and temperature were 360 kg/h and at an inlet temperature of 16.3 °C, the photovoltaic/thermal module reached the maximum thermal efficiency of 98.0 % under solar irradiance of 875 W/m² and an ambient temperature of 29 °C. The integrated cooling system reduced the rear surface temperature of the photovoltaic module by 54.3 °C. A theoretical model of the system was also developed and validated using the experimental data. A case study on domestic hot water supply for a single-family house demonstrated the practical applicability of the system. Results drawn prove that the designed photovoltaic/thermal system can contribute substantially to decarbonization and green energy transition for commercial and residential buildings where available space is scarce.