A novel renewable energy storage system based on reversible SOFC, hydrogen storage, Rankine cycle and absorption refrigeration system

A global shift towards a more sustainable and eco-friendly future has prominently emphasized on the need to develop cleaner and renewable energy sources for various applications in our day-to-day life. A fuel cell is an electrochemical system that directly transforms the chemical energy of the fuel into electrical power without passing through any intermittent thermal layers. As a result, the Carnot's performance has no bearing on it. High efficiency and low noise pollution are some of the key advantages of fuel cells. Power generation from fuel cells can curtail costly transmission lines and minimize the losses during the transmission for a distributed system. Moreover, the power plant size is independent of fuel cell performance. The utilization of the trigeneration system increases the efficiency of high-temperature solid oxide fuel cell because the heat dissipated by the fuel cell is now utilized for cogeneration. In this paper, energy analysis of an integrated system consisting of a solid oxide fuel cell operating in fuel cell mode and electrolyser mode coupled with Rankine cycle, metal hydride system and absorption refrigeration system for power generation, heating and cooling applications has been performed. The study shows a significant improvement in the performance of the integrated plant compared to the power generation using combination of the solid oxide fuel cell and the Rankine cycle alone. It was found that the maximum efficiency in fuel cell mode occurs at an inlet flow temperature of 900 K. The net efficiency with and without organic Rankine cycle (ORC) in this case is estimated to be 44.41 % and 40%, respectively. However, maximum net efficiency occurs at a current density of 0.6 A/cm(2), wherein efficiency with and without ORC is 46.54 % and 45.84%, respectively. In the electrolyser mode, the maximum overall efficiency of the system was observed to be 88.82 %.