Numerical investigation of a new combined energy cycle based on Miller cycle, Organic Rankine cycle, Stirling engine and alkaline fuel cell

Using a combined energy cycle based on conventional and/ or clean energy sources can be a suitable option to dominate the limitations in the field of energy. Meanwhile, the select of the prime power source in such processes is a challengeable issue. The selection of the prime power source from renewable sources and in addition the use of system waste heat can lead to enhance power generation. In the present work, an energy system based on conventional energy sources and clean technology is introduced and investigated. The new integrated hybrid energy cycle is composed of Miller cycle engine (MC), alkaline fuel cell (AFC), alkaline electrolyzer, Organic Rankine cycle (ORC) system and Stirling engine. MC and AFC are used as the main power sources of the cycle. On the other hand, ORC and Stirling engine for generating more electricity from the waste heat of the cycle are applied. The electrolyzer embedded in the cycle receives its electricity from the MC and provides the required inputs of the AFC. Although many studies had been done on the integration of various power generation sources with different energy cycles, attempts had not been done to establish a study on the hybrid of MC, AFC, alkaline electrolyzer, Stirling engine and ORC to produce additional electricity. Results revealed that the introduced energy system generates 3.75 kW of electric power. The portion of MC, fuel cell, ORC, and Stirling engine in electric power production is 71.2, 10.8, 9.5 and 8.5%, respectively. However, the alkaline electrolyzer consumes 2.06 kW of power and generates 48.2 g/h of H2 fuel. It was also found that the cycle exergy destruction is 3.34 kW. In addition, the use of MC and AFC heat dissipation heat can enhance power generation. © 2021 The Authors