Organic Rankine Cycle as the Waste Heat Recovery Unit of Solid Oxide Fuel Cell: A Novel System Design for the Electric Vehicle Charging Stations Using Batteries as a Backup/Storage Unit

Abstract

The novelty of this study is to suggest a novel design for electric vehicle charging stations using fuel cell technology. The proposed system benefits from the Organic Rankine Cycle (ORC) to utilize the exhaust energy of the Solid Oxide Fuel Cell (SOFC) stacks in addition to the Lithium-Ion battery to improve the efficiency by partial-load operation of the stacks at night. The study is supported by the thermodynamic analysis to obtain the characteristics of the system in each state point. To analyze the operation of the system during the partial-load operation, the dynamic performance of the system was developed during the day. Furthermore, the environmental impacts of the system were evaluated considering eighteen parameters using a life-cycle assessment (LCA). LCA results also revealed the effects of different fuels and working fluids for the SOFC stacks and ORC, respectively. Results show that the combination of SOFC and ORC units can generate 264.02 kWh with the respective overall energy and exergy efficiencies of 48.96% and 48.51%. The suggested 264.02 kWh contributes to global warming (kg CO2 eq) by 5.17 × 105, 8.36 × 104, 2.5 × 105, 1.98 × 105, and 6.79 × 104 using methane, bio-methanol, natural gas, biogas, and hydrogen as the fuel of the SOFC stacks.