A global heat flow topology for revealing the synergistic effects of heat transfer and thermal power conversion in large scale systems: Methodology and case study

• Published in: Energy (Oxford) 2024-03, Vol.290, p.130203, Article 130203
• Main Authors: Wang, Zhe, Cao, Menglong, Tang, Haobo, Ji, Yulong, Han, Fenghui
• Format: Article
• Language: English
• Subjects: algorithms; case studies; cold; energy recovery; entransy; Entransy transfer; exergy; gasification; Global modeling and optimization; heat flow; Heat flow topology; heat tolerance; heat transfer; Large scale complex system; mathematical models; seawater; synergism; Synergistic effects; temperature; topology
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2023.130203

In the processes of modeling, optimization, heat transfer analysis, and thermal power conversion analysis in large-scale complex systems, challenges are encountered regarding intricate design and optimization. In this paper, a global heat flow topology is proposed that reveals the synergistic effect of heat transfer and thermal power conversion in large-scale systems. The approach involves the construction of a heat flow topology, mathematical model development, analysis of specific parameters, and multi-objective optimization. It integrates various methods and tools, including heat flow topology, numerical simulation tool, entransy transfer analysis, global thermal resistances visualization, genetic algorithm (GA), and technique for order preference by similarity to ideal solution (TOPSIS). By using the LNG cold energy recovery and regasification process in floating storage and regasification units (FSRU) as a case study, the methodology provides a comprehensive understanding of the interactions and conversions between heat transfer and thermal power within the system. The results demonstrate that the optimal configuration achieves a maximum thermal efficiency of 21.73 % and a maximum cold recovery efficiency of 58.48 %. Additionally, the interaction between LNG pressure and seawater temperature exhibits limited synergistic impact on both LNG cold exergy efficiency and entransy transfer efficiency. Similarly, the combined influence of LNG pressure and evaporator temperature shows weak synergistic effects on parameters such as supply/demand ratio, thermal efficiency, and entransy transfer efficiency. The analysis of the global thermal resistance bubble chart reveals the significant impact of evaporator temperature and seawater temperature on the evaporator resistance, as well as the notable impact of LNG pressure on the condenser resistance. [Display omitted] •Proposed a global modeling and optimization method for large-scale system.•Constructed heat flow topology to describe heat transfer and heat-work conversion.•Energy, exergy, entransy analysis and multi-objective optimization are carried out.•The global overall thermal resistances change is visualized by bubble diagram.