Comprehensive Assessment of a Coupled LiBr/H2O Absorption Refrigeration/ORC System for Low-Grade Residual Heat Recovery Based on Advanced Exergy and Exergoeconomic Analysis

Conventional and advanced exergy and exergoeconomic analyses are investigated on a coupled LiBr/H2O cycle/ORC system, which recovers low-grade residual heat to generate electricity. Exergy destruction rates, exergy destruction cost rates, and investment cost rates are calculated based on the exergy balance, cost balance, and auxiliary equations. The results indicate that 32.02% of the irreversibility rates, 37.66% of the irreversibility cost rates, and 25.83% of the investment cost rates can be eliminated. The ORC evaporator contributes to the highest irreversibility rate, and the LiBr absorber has the supreme investment cost rate. 83.17% of the exergy destruction rates are endogenous, which means that each component itself has a critical effect on system performance. In the advanced exergoeconomic analyses, 77.30% of the investment cost is generated by the components themselves. Except for LiBr pumps, other components reduce their exergy destruction cost rates preferentially. Optimizing methods to decrease the irreversibility of the system are also provided by this analysis.