Comprehensive Modeling Study of the Electrical Performance of a Sono-Electrolyzer under a Voltage and Current Sources Supply: From Grey to Green Hydrogen

Hydrogen production from water electrolysis is seen as a promising technology to produce hydrogen with high purity of 99.99%. However, the increase of the ohmic resistance in the electrolyte remains a challenge for the electrolytic technique. In the present work, we study the transition from grey hydrogen to green hydrogen using alkaline electrolysis (25% w/w KOH solution electrolysis). We compare hydrogen production efficiency using a voltage source simulating the conventional DC generator, and a current source simulating the PV power supply. Water electrolysis was coupled to an indirect ultrasound source in order to investigate its effect on hydrogen production process in both cases of power supply. The question was tackled experimentally using an H-cell electrolyzer and an ultrasonic bath, and numerically using a MatLab code. Energy conversion efficiency and hydrogen production rate were determined both experimentally and through simulation. It was demonstrated that the integration of sonication reduces the ohmic resistance within the electrolyzer and thus decreases the cell voltage for the same current, which enhances the energy efficiency in the case of current source for the same hydrogen production rate. For instance, an enhancement of 1% was recorded in the energy efficiency using a current source of energy, while is equals 2.68% in the case of voltage source. Therefore, the coupled of sono-electrolysis process to solar PV seems to be a promising pathway for an environmentally friendly hydrogen production technique from an energetic perspective.