Entropy Flow Analysis of Thermal Transmission Process in Integrated Energy System Part II: Comparative Case Study

Abstract

The dynamic characteristics of thermal energy play an important role of multi-scale coupling among heterogeneous energy sources in integrated energy systems (IES). In Part I, for the purpose of accurately describing the dynamic processes of thermal energy transmission, the theoretical approach and models were proposed and verified by numerical simulation. In this part, an innovative analytical method based on entropy flow was derived on the basis of theory developed in Part I, which can assess the quantity and quality of thermal transport. A comparative case study indicates that the change trend of entropy flow of each node is consistent with the change of available power, but independent of temperature. The node entropy flow is increased compared with the algebraic sum of branch entropy flow, which reflects the phenomenon of entropy generation in the mixing process; while the change of available power is just the opposite. This means the irreversible entropy generation at the node leads to loss of the available thermal power. Therefore, it is more accurate to describe the dynamic thermal transmission process on the scale of entropy. This proves the effectiveness of the models proposed in Part I as well as the methods in this part from the perspective of application.