Effect of water electrolysis temperature of hydrogen production system using direct coupling photovoltaic and water electrolyzer

Abstract

We propose control methods of a photovoltaic (PV)-water electrolyzer (ELY) system that generates hydrogen by controlling the number of ELY cells. The advantage of this direct coupling between PV and ELY is that the power loss of DC/DC converter is avoided. In this study, a total of 15 ELY cells are used. In the previous researches, the electrolyzer temperature was constantly controlled with a thermostat. Actually, the electrolyzer temperature is decided by the balance of the electrolysis loss and the heat loss to the outside. Here, the method to control the number of ELY cells was investigated. Maximum Power Point Tracking efficiency of more than 96% was achieved without ELY temperature control. Furthermore we construct a numerical model taking into account of ELY temperature. Using this model, we performed a numerical simulation of 1-year. Experimental data and the simulation results shows the validity of the proposed control method. KEYWORDS Photovoltaic-water electrolyzer system; hydrogen energy system; control method; MPPt efficiency ARTICLE HISTORY