Design and modeling of a hybrid reversible solid oxide fuel cell - organic Rankine cycle

A combined-cogenerative system is here presented and analyzed in order to prove the concept and viability of coupling two of the most promising technologies nowadays available on the market of renewable and storage energy. A model based on reversible Solid Oxide Fuel Cell and Solid Oxide Electrolyzer (rSOFC/SOE) system is coupled with an Organic Rankine Cycle (ORC) system to exploit the waste heat coming from the hydrogen conversion process. The ORC is able to recover a considerable part of the waste heat energy coming from both the power-to-hydrogen and water-to-hydrogen processes. The fuel cell analyzed is able to operate as SOE system producing hydrogen when electric power is available from the grid. The design optimization of the comprehensive layout, however, is nontrivial because there exist many design variables and practical considerations. The model is based on data available from previous experimental campaigns and it is used to complete the design of the layout and to properly size the system's components. A simplified approach to implement the Steady State (SS) behavior of the whole system is then proposed. Figure 1, the “ideal” flows of the three valuable sources of the system studied (thermal, electric power and hydrogen).