Performance evaluation and optimization design of integrated energy system based on thermodynamic, exergoeconomic, and exergoenvironmental analyses

With increased cooling load demand and long-term system operation, an existing integrated energy system (IES) has the problems of insufficient cooling capacity, aging of equipment, and high carbon emissions. This paper conducts thermodynamic, exergoeconomic, and exergoenvironmental analyses to evaluate the performance and improvement potential of the system. Then, the advanced exergy analysis is performed to further determine the specific optimization measures. Finally, an optimal IES integrated with parabolic trough collectors, absorption heat pump, and absorption refrigeration is designed. The comparison results show that the natural gas consumption of the optimal IES is reduced by 22.53% while the cold output is improved by 50%, and the system energy efficiency and the system exergy efficiency are increased by 12.90% and 1.99%, respectively. Meanwhile, the total cost rate and the total environmental impact rate of the system are decreased by 26.25% and 35.87%, respectively. Furthermore, the parameter study is carried out to evaluate the effects of various parameters on the performance of the optimal IES. The research could provide theoretical and practical application guidance for performance evaluation and transformation optimization of the IES.