Performance enhancement of integrated energy system using a PEM fuel cell and thermoelectric generator

Coupling different energy conversion systems together to have more sustainable energy systems can be a promising way to cope with the challenges of the energy consumption crisis. In the current work, an organic Rankin cycle (ORC) has been coupled with some other units like the Kalina cycle and some other subunits including a proton exchange membrane (PEM) electrolyzer, fuel cell, and thermoelectric generator (TEG). Two layouts of systems have been considered for evaluation. In the modified system to enhance the overall performance of the unit, fuel cells and a TEG have been utilized. Having analyzed the system from technical and economical viewpoints it is concluded that the proposed system has an energy and exergy efficiency of 16.77% and 61.69%, respectively. The results show that 0.0001632 mol/h of hydrogen can be produced with the electrolyzer system. The comparison of the suggested system with basic plant indicated that the suggested system generated 155.33 kW electrical power while the basic system generated 146.2 kW. Exergy examination represents that the condenser with 20.13 kW has the highest rate of exergy destruction rate. A parametric analysis has been performed for different parameters of the system and the calculation represents that the energy efficiency and overall exergy destruction rate with the defined electricity cost rate show a different behavior, which indicates the necessity of multi-objective optimization. For the improved plant according to the four parameters, multi-objective optimization has been done according to the genetic algorithm and the most optimal state of the system has been extracted based on three-objective optimization. In the optimum state, the exergy efficiency of the system and electricity cost obtained 62% and 10.72 $/h.