Strengths and Limitations of Exergy Analysis

An exergy analysis identifies the location, the magnitude and the sources of thermodynamic inefficiencies in a thermal system. This information, which cannot be provided by other means (e.g., an energy analysis), is very useful for improving the overall efficiency and cost effectiveness of a system or for comparing the performance of two systems. This paper deals with the use of exergetic variables, i.e., those variables calculated in an exergy analysis to characterize each component and some streams of the system. Their critical review will identify the strengths and the limitations of an exergy analysis. The following discussion is limited to systems at steady-state operation. The results can easily be extended to other systems