Exergy-Based Analysis of Aircraft Environmental Control Systems – Integration into Model-Based Design and Potential for Aircraft System Evaluation

The analysis of complex thermodynamic systems with exergetic and 2nd law methods is continually performed for various fields of engineering. This also applies to environmental control systems (ECS) of aircraft. This paper focuses on methods of exergy and energy analysis applied to ECS. It gives a survey of the published material and identifies the state of the art. Furthermore, this analysis includes an example with a conventional ECS cycle on how these methods can be integrated into a corresponding model-based design process. Conventional exergy methods allow the location of exergy destruction throughout a system, but ignore the mutual interdependencies of the system components. Advanced exergy analysis provides a splitting of the exergy destruction in each component into different parts. This method enables a realistic assessment of the potential for improving the thermodynamic efficiency of each component. The different methods are discussed with an evaluation of a conventional ECS cycle regarding their optimization potentials and conclusions are drawn.