Energy, exergy, exergoeconomic, environmental (4E) evaluation and multi-objective optimization of a novel SOFC-ICE-SCO2-HRSG hybrid system for power and heat generation

Abstract

To achieve sustainable development of the global energy system, it is essential to develop efficient and cost-effective cogeneration systems. This paper introduces a new cogeneration system named SOFC-ICE-SCO2-HRSG, which combines solid oxide fuel cells (SOFC), internal combustion engines (ICE), supercritical carbon dioxide (SCO2) power cycles, and heat recovery steam generators (HRSG) to generate electricity and heating simultaneously. The proposed system offers a promising solution for achieving high efficiency and cost-effective clean power generation and heating. Energy, exergic, exergoceconomic, and environmental analyses were conducted to evaluate the system's performance. The impact of fuel flow, steam carbon ratio, and other parameters on the system's efficiency was also analyzed. The system was optimized using a genetic algorithm, and the optimal operating condition was determined using the TOPSIS method. The results indicate that the proposed system can achieve a total output power and net output power of 345.58 kW and 288.94 kW, respectively, under optimal conditions, with a 1:1 fuel flow ratio between the SOFC and ICE systems. The total unit cost of the product can be as low as 42.98 $/GJ, while the theoretical and actual generation efficiencies can reach 48.00% and 40.13%, respectively. The overall energy efficiency and exergy efficiency were found to be 65.82% and 42.28%, respectively. Additionally, the system can achieve a CO2 emission rate of 0.4712 kg/kW·h, and the social cost for pollutant emissions was estimated to be 3.34 $/GJ. This study provides evidence that the proposed hybrid system has excellent performance in terms of efficiency, cost, and environmental impact. As an advanced energy conversion technology, it holds great potential for practical applications in meeting energy demands while reducing environmental pollution.