Power generation in organic Rankine cycle from wasted heat of geothermal energy and boilers to produce hydrogen using a proton exchange membrane electrolyzer

The use of water electrolysis to produce hydrogen gas has received much attention in recent years, because in this method, water is decomposed into hydrogen and oxygen gas without any pollution. In this research, an organic Rankine cycle (ORC) is simulated and analyzed to utilize waste heat to run an electrolyzer. The power generated by ORC is used to produce hydrogen gas in proton exchange membrane electrolyzer (PEME). Model and codes for the electrolyzer is done by EES software, and thermodynamic analyzes are utilized in order to examine the performance of the proposed model. For the evaporator temperature of 67 ℃, the ORC power and thermal efficiency are obtained at 220 kW and 8.5 %, respectively. The production capacity of the electrolyzer considered in this research is 27 kg per hour of hydrogen gas with a temperature of 80 ℃ and a pressure of 101 kPa. Water electrolysis is performed using direct current between two electrodes, anode and cathode, which are separated by a membrane. To validate the simulated model, membrane potential at different values of current density is calculated.