Eco-efficiency of control configurations using Exergy

For general multi-input multi-output (MIMO) processes, thermodynamic properties like exergy have been previously used for the development of eco-efficiency analysis tools e.g. Relative Exergy Array (REA) [1, 2], and Exergy Eco-efficiency Factor (EEF) [3]. The REA is easy to use, compares several control scheme candidates for single units and ranks them according to their exergy interactions between control loops. The EEF provides means to determine the effect of a control scheme on the eco-efficiency of the whole process. In this paper, our intention is to justify the use of EEF and REA, compare EEF recommendations to REA, and consider EEF for the whole process eco-efficiency and discuss the similarities and differences between REA and EEF. Furthermore these results of testing REA and EEF on a realistic case study will be analysed to provide some practical recommendations on their usage.