Techno-economic optimization of the integration of an organic Rankine cycle into a molten carbonate fuel cell power plant

This study proposes a simple economic model to optimize the integration of an organic Rankine cycle into a molten carbonate fuel cell power plant. The optimization was conducted with five different types of working fluids, and an exergetic optimization was also done for comparison. In addition, sensitivity analysis was conducted to provide better insight into the behavior of the ORC system. The optimization results show that the optimum economic point and the optimum exergetic point are different, and a maximum profit can be achieved for the ORC system with economic optimization. Overall, in most cases, the profit is highest when the ORC system uses n-butane; however, R152a yields better profit when the ambient temperature is below 5 degrees C. In addition, all ORC systems show positive profit when the price of electricity is above 0.05 USD/kWh. For sensitivity analysis, two simulation experiments were conducted to observe the effect of changes in the feed gas temperature and the sales price of electricity on the optimization results. As a result, changes in the sale price of electricity are very critical, but changes in the feed gas temperature are not important.