Flexible and optimized operation of integrated energy systems based on exergy analysis and pipeline dynamic characteristics
Flexible and optimized operation of integrated energy systems based on exergy analysis and pipeline dynamic characteristics
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DOI：
10.3389/fenrg.2023.1203720
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发表时间：
2023-06
期刊：
影响因子：
--
通讯作者：
Xiaolu Li;Tong Wu;Shunfu Lin
中科院分区：
文献类型：
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作者：
Xiaolu Li;Tong Wu;Shunfu Lin
面对能源危机和严重的环境污染，提高综合能源系统的能源利用效率显得尤为重要。现有的IES优化运行的研究大多是基于热力学第一定律，没有考虑能量的质量和方向属性。所获得的策略通常不能准确地反映能量质量的差异。根据热力学第二定律，首先分析了不同形式能量的能质系数，并将火用流表示为能质系数与能流的积。基于能量网络理论，建立了电-气-热一体化能源系统的分析模型。其次，对燃气热力网络的动态特性和相应的储能容量进行了建模和分析。考虑到燃气热力管网的动态特性，根据天然气和热能系统的能质系数，分析了管网中储存的有效能，并结合机组运行情况分析了各子系统的柔性能力。然后对电-气-热IES 39-20-6系统进行了仿真分析。结果表明，从能量角度来看，耦合设备中的损失仅占总能量损失的29.05%，而从火用角度来看，其比例高达46.47%。此外，在火用分析下，考虑了燃气热力管网的动态特性后，系统的弃风率从11.22%降低到8.27%。
Given the energy crisis and severe environmental pollution, it is crucial to improve the energy utilization efficiency of integrated energy systems (IESs). Most existing studies on the optimal operation of IESs are based on the first law of thermodynamics without considering energy quality and direction attributes. The obtained strategies generally fail to accurately reflect the difference in energy quality. Based on the second law of thermodynamics, we first analyzed the energy quality coefficients of energy in different forms and expressed the exergy flow as the product of energy quality coefficients and energy flow. An exergy analysis model of the electric–gas–thermal integrated energy system was also established based on the energy network theory. Second, modeling and analyzing the dynamic characteristics of gas–thermal networks and the corresponding energy storage capacities were explored. Considering the dynamic characteristics of the gas–thermal pipeline network, the useful energy stored in the pipelines was analyzed based on the energy quality coefficients of natural gas and the thermal energy system, and the flexibility capacity of each subsystem was also analyzed in combination with the operation of units. A simulation analysis was then conducted on the electric–gas–thermal IES 39-20-6 system. The results demonstrated that from an energy perspective, the loss in the coupling equipment only accounts for 29.05% of the total energy losses, while from an exergy perspective, its proportion is as high as 46.47%. Besides, under the exergy analysis, when the dynamic characteristics of the gas–thermal pipeline network are taken into account, the wind curtailment rates of the system decrease from 11.22% to 8.27%.