Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems
Highly integrated energy systems are on the rise due to increasing global demand. To capture the underlying physics of such interdisciplinary systems, we need a modern framework that unifies all forms of energy. Here, we apply modified Lagrangian mechanics to the description of multi-energy systems....
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| Format: | Article |
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MDPI AG
2024-09-01
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| Series: | Entropy |
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| Online Access: | https://www.mdpi.com/1099-4300/26/9/791 |
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| author | Ke Xu Yan Qi Changlong Sun Dengxin Ai Jiaojiao Wang Wenxue He Fan Yang Hechen Ren |
| author_facet | Ke Xu Yan Qi Changlong Sun Dengxin Ai Jiaojiao Wang Wenxue He Fan Yang Hechen Ren |
| author_sort | Ke Xu |
| collection | DOAJ |
| description | Highly integrated energy systems are on the rise due to increasing global demand. To capture the underlying physics of such interdisciplinary systems, we need a modern framework that unifies all forms of energy. Here, we apply modified Lagrangian mechanics to the description of multi-energy systems. Based on the minimum entropy production principle, we revisit fluid mechanics in the presence of both mechanical and thermal dissipations and propose using exergy flow as the unifying Lagrangian across different forms of energy. We illustrate our theoretical framework by modeling a one-dimensional system with coupled electricity and heat. We map the exergy loss rate in real space and obtain the total exergy changes. Under steady-state conditions, our theory agrees with the traditional formula but incorporates more physical considerations such as viscous dissipation. The integral form of our theory also allows us to go beyond steady-state calculations and visualize the local, time-dependent exergy flow density everywhere in the system. Expandable to a wide range of applications, our theoretical framework provides the basis for developing versatile models in integrated energy systems. |
| format | Article |
| id | doaj-art-d425ecce4d574a50b5e1265dd9cb1bcf |
| institution | OA Journals |
| issn | 1099-4300 |
| language | English |
| publishDate | 2024-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Entropy |
| spelling | doaj-art-d425ecce4d574a50b5e1265dd9cb1bcf2025-08-20T01:55:27ZengMDPI AGEntropy1099-43002024-09-0126979110.3390/e26090791Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy SystemsKe Xu0Yan Qi1Changlong Sun2Dengxin Ai3Jiaojiao Wang4Wenxue He5Fan Yang6Hechen Ren7Electric Power Research Institute of State Grid, Tianjin Electric Power Company, Tianjin 300010, ChinaElectric Power Research Institute of State Grid, Tianjin Electric Power Company, Tianjin 300010, ChinaCenter for Joint Quantum Studies, Department of Physics, Tianjin University, Tianjin 300350, ChinaElectric Power Research Institute of State Grid, Tianjin Electric Power Company, Tianjin 300010, ChinaCenter for Joint Quantum Studies, Department of Physics, Tianjin University, Tianjin 300350, ChinaCenter for Joint Quantum Studies, Department of Physics, Tianjin University, Tianjin 300350, ChinaCenter for Joint Quantum Studies, Department of Physics, Tianjin University, Tianjin 300350, ChinaCenter for Joint Quantum Studies, Department of Physics, Tianjin University, Tianjin 300350, ChinaHighly integrated energy systems are on the rise due to increasing global demand. To capture the underlying physics of such interdisciplinary systems, we need a modern framework that unifies all forms of energy. Here, we apply modified Lagrangian mechanics to the description of multi-energy systems. Based on the minimum entropy production principle, we revisit fluid mechanics in the presence of both mechanical and thermal dissipations and propose using exergy flow as the unifying Lagrangian across different forms of energy. We illustrate our theoretical framework by modeling a one-dimensional system with coupled electricity and heat. We map the exergy loss rate in real space and obtain the total exergy changes. Under steady-state conditions, our theory agrees with the traditional formula but incorporates more physical considerations such as viscous dissipation. The integral form of our theory also allows us to go beyond steady-state calculations and visualize the local, time-dependent exergy flow density everywhere in the system. Expandable to a wide range of applications, our theoretical framework provides the basis for developing versatile models in integrated energy systems.https://www.mdpi.com/1099-4300/26/9/791integrated energy systemsexergy flowLagrangian fluid mechanics |
| spellingShingle | Ke Xu Yan Qi Changlong Sun Dengxin Ai Jiaojiao Wang Wenxue He Fan Yang Hechen Ren Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems Entropy integrated energy systems exergy flow Lagrangian fluid mechanics |
| title | Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems |
| title_full | Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems |
| title_fullStr | Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems |
| title_full_unstemmed | Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems |
| title_short | Exergy Flow as a Unifying Physical Quantity in Applying Dissipative Lagrangian Fluid Mechanics to Integrated Energy Systems |
| title_sort | exergy flow as a unifying physical quantity in applying dissipative lagrangian fluid mechanics to integrated energy systems |
| topic | integrated energy systems exergy flow Lagrangian fluid mechanics |
| url | https://www.mdpi.com/1099-4300/26/9/791 |
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