Thermodynamic performance of cycle combined large temperature drop heat exchange process:Theoretical models and advanced process

High-temperature-drop heat exchange technology, which can be realized by the proper configuration of heat-driven heat pump cycles, is an important solution for the Large-scale District Heating project. Cycle combined heat exchange process model is a theoretical standard for the analysis of High-temperature-drop heat exchange process, the thermodynamic performance and the heat-work conversion relationship of the this kind of process need to be researched to approach the theoretical optimal heat exchange effect. In this paper, with the analytical method, the thermodynamic performance including the medium temperature variation, useful work transmission, operation efficiency and heat exchange effect. Various values of heat engine high-grade temperature, heat exchange efficiency and endo-irreversibility factor are considered to analyze their effects on the outlet temperature lift/drop. The quantity and location of the exergy destruction distribution is also researched. Moreover, the relation between the heat exchange effect and the distribution of the exergy loss is researched, by which the advanced process model is proposed. With re-distribution of the exergy destruction, the advanced process has a promoted heat exchange effect compared with the original one. The result and conclusion of the this paper will offer a guidance principle for the component configuration of the practical application.