Abstract With the rapidly increasing capacity of renewable energy production, the volatile nature of, e.g., wind and solar power necessitates solutions for storing excess energy. A finite-element model for simulating a geomembrane energy storage system is developed, in order to aid the development of the system and provide first insights into the performance of the system. Conceptually, energy is stored by pumping water from a nearby surface reservoir into a subsurface reservoir confined by a geomembrane, which lifts the overlying mass of soil, thereby increasing the potential energy due to gravity. An axisymmetric finite-element model is developed employing fluid cavity elements and fluid exchange links to simulate inflow and outflow of the reservoir, which resembles energy storage and energy re-harvest, respectively. A sophisticated constitutive model for a granular soil is employed using a hypoplastic model with intergranular strain extension, which includes essential characteristics as stress and density dependency, critical-state behavior as well as stress reversals. Analysis of repeated storage cycles provides realistic but undesirable deformation patterns, encountered by increasing irreversible displacements with advancing cycles. The reliable results of the model directly provides estimates of energy efficiency and can serve as a tool for further development and optimization of the energy storage system.

中文翻译：

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使用流体腔元件的地下充气岩土储能系统的整体模拟

摘要 随着可再生能源生产能力的迅速增加，风能和太阳能等的波动性使得存储过剩能量的解决方案成为必要。开发了一种用于模拟土工膜储能系统的有限元模型，以帮助系统的开发并提供对系统性能的初步了解。从概念上讲，能量是通过将水从附近的地表水库泵入由土工膜限制的地下水库来存储的，土工膜提升了上覆的土壤质量，从而增加了重力势能。开发了一个轴对称有限元模型，采用流体腔单元和流体交换链接来模拟储层的流入和流出，分别类似于能量存储和能量再收集。颗粒土的复杂本构模型使用具有粒间应变扩展的亚塑性模型，其中包括应力和密度依赖性、临界状态行为以及应力反转等基本特征。重复存储周期的分析提供了现实但不受欢迎的变形模式，随着周期推进，不可逆位移增加而遇到。该模型的可靠结果直接提供了对能源效率的估计，并可作为进一步开发和优化储能系统的工具。重复存储周期的分析提供了现实但不受欢迎的变形模式，随着周期推进，不可逆位移增加而遇到。该模型的可靠结果直接提供了对能源效率的估计，并可作为进一步开发和优化储能系统的工具。重复存储周期的分析提供了现实但不受欢迎的变形模式，随着周期推进，不可逆位移增加而遇到。该模型的可靠结果直接提供了对能源效率的估计，并可作为进一步开发和优化储能系统的工具。