Comprehensive energy analysis of a photovoltaic thermal water electrolyzer

Abstract

The use of photovoltaic thermal (PVT) technologies enables improvement in the electrical efficiency of a photovoltaic (PV) module by reducing the temperature of the PV module via active waste heat removal. In current PVT systems, the removed heat is mainly used for specific applications, such as water and/or room heating, but their need is intermittent and seasonal. For a more efficient and versatile use of the removed waste heat, we propose a new architecture where the PV module is integrated with a dual-functional electrolyzer that removes the waste heat by active cooling and produces hydrogen via electrolysis. The excess heat from the PV cell is utilized to enhance the reaction kinetics of the electrolysis process (due to an increase in temperature) inside an electrolyzer, which is located below the PV module. In this paper, we used finite-element analysis (FEA) simulations to optimize the geometry and operating conditions of an electrolyzer to maximize overall energetic efficiency and hydrogen production. To evaluate the practical feasibility of the approach, we performed a comprehensive energy analysis of the PVTE system using data from Phoenix, AZ. The energetic efficiency of the proposed PVTE system was calculated to be 56–59%, which is comparable to those of current PVT systems. Additionally, the integration of the electrolyzer with the PV module led to an almost 2.5-fold increase in hydrogen production compared to a stand-alone electrolyzer operated at ambient temperature. The analyzed hybrid approach potentially represents a viable and useful alternative for utilization of waste heat energy from PV cells. This approach may further increase the use of photovoltaic technologies as a renewable energy source.