Dynamic Analysis and Simulation of Exergy Based on the Energy Network Theory

The integrated energy system modeling method based on the energy network theory can break down theoretical and technical barriers between different energy subsystems. This study proposed a novel exergy analysis method based on the energy network theory. The proposed method taps the energy efficiency potential of an integrated energy system. To capture common exergy transfer characteristics, the universal transmission law of exergy based on the second law of thermodynamics was proposed. Different forms of dynamic exergy transfer mechanisms including electrical exergy, thermal exergy, and pressure exergy were then analyzed in a time- varying energy network with the energy network theory modeling method. With the same exergy analysis method, the dynamic evolution mechanism of exergy in energy conversion elements was also proposed. Furthermore, a Runge Kutta algorithm and the generalized Kirchhoff law were combined to calculate the exergy in an integrated energy system, which could be simplified into an energy network topological diagram. A case study was used to analyze the cause, distribution, and size of the exergy loss and storage in different energy networks, verifying the feasibility of the proposed exergy analysis model and method.