Multi-Objective Optimization of the Vapour Cycle System of an Aircraft Environmental Control System using Exergy Analysis

Abstract

The adoption of exergy analysis for aircraft systems is slow. For single phase systems the equations are relatively simple for calculating the exergy destruction and slightly easier to formulate from fundamentals. When it comes to two-phase systems, the dependence on correlations, in the absence of analytical equations, especially for the compact heat exchangers employed in the aircraft environmental control systems, requires a careful look at all the aspects to carry out the exergy analysis. A typical vapor cycle system for the aircraft application is analyzed to carry out the multi-objective optimization of the system using exergy analysis. Using the correlations from open literature for the evaporation and condensation, a trainer aircraft VCS configuration using R134 refrigerant was analyzed for its design case. Mathematical model developed for this was solved using the MATLAB optimization module to arrive at the core dimensions of the evaporator and the condenser. Compared to the dimensions of the units on the aircraft there is a scope of 40% reduction in the weight of the system at the same time optimizing the exergy destruction.