Multi-objective optimization and thermo-economic analysis of an enhanced compression-absorption cascade refrigeration system and ORC integrated system for cooling and power cogeneration

Waste heat recovery techniques can greatly improve the energy efficiency and relieve the energy crisis. The integration of compression-absorption cascade refrigeration system (CACRS) and Organic Rankine Cycle (ORC) can achieve cooling and power cogeneration utilizing waste heat. However, the simultaneous optimization of integrating configuration and operating parameters has not been considered in recent studies, neglecting the complex interactive relationship within the integrated system consequently. To overcome these limitations, an enhanced CACRS-ORC integrated system, containing more coupling possibilities and more routes in driving the integrated system with waste heat, is proposed and investigated in this paper. To examine the trade-off in the economic and thermodynamic performances, a multi-objective optimization-based method, aiming at the simultaneous minimization of the total annualized cost (TAC) and the total exergy destroy (Extotal destroy), is developed to determine the optimal configuration and operating parameters of the integrated system. The derived Pareto solutions reveal the contradictory relationship between the two objectives, and the thermo-economic analysis is executed to show the impact of system configuration and operating parameters on economy and thermodynamics. Sensitive analysis is also performed to reveal the effects of key parameters on the structural configuration and thermo-economic performances.