Exergy Based Analysis for the Environmental Control and Life Support Systems of the International Space Station

摘要

When optimizing the performance of complex systems, a logical area for concern is improving the efficiency of useful energy. The energy available for a system to perform work is defined as a system's exergy content Interactions between a system's subsystems and the surrounding environment can be accounted for by understanding various subsystem exergy efficiencies. Exergy balance of reactants and products, and enthalpies and entropies, can be used to represent a chemical process. Heat transfer exergy represents heat loads, and flow exergy represents system flows and filters. These elements allow for a system level exergy balance. The exergy balance equations are developed for the subsystems of the Environmental Control and Life Support (ECLS) system aboard the International Space Station (ISS). The use of these equations with system information would allow for the calculation of the exergy efficiency of the system, enabling comparisons of the ISS ECLS system to other systems as well as allows for an integrated systems analysis for sytem optimization.