The effect of voltage and electrode types on hydrogen production powered by photovoltaic system using alkaline and PEM electrolyzers

Abstract

In this present work, we have investigated the performance of two kinds of electrolyzers: Proton exchange membrane (PEM) and Alkaline water electrolyzers (AWE), which are powered by a photovoltaic (PV) system. The results showed that PEM needs less voltage than Alkaline to produce the same amount of hydrogen. For the Alkaline electrolyzer, two types of solutions have been used as an electrolyte: Potassium Hydroxide (KOH) and saline water. Experimental tests revealed that the optimal concentration ratio to achieve the best flow rate of hydrogen corresponds to 100 % seawater. The best production of hydrogen, using the Alkaline electrolyzer, has been found with KOH as the electrolyte. In fact, the accumulated quantities of hydrogen produced, during the same experiment time of 10 h, are 10300 ml/day if using PEM electrolyzer, 3600 ml/day and 450 ml/day if using alkaline with the KOH solution and sea water, respectively. So, it requires to use almost 8 units of sea water as an electrolyte to get the same daily hydrogen production if using KOH solution as electrolyte. It is observed that the hydrogen production increases with the increase of the incident solar irradiation. Also, the system (PV-PEM) has higher efficiency than the system (PV-Alkaline) and the total system efficiency decreases from 15 % to 8 % with the increase of incident solar irradiation. The results indicated that the higher production of hydrogen is obtained by using aluminum electrodes than copper or stainless-steel electrodes.