The investigations show that an undeniable part of future smart energy system, which is to be based on 100% clean energies, is energy storage units. Indeed, due to the intermittent inherent of the main source of renewable energies, e.g., wind and solar, energy storage systems will be highly in service in the future. In this regard, investigation of the impacts of combining nanopowders on the thermal behavior of PCM through a thermal energy storage bed in various operational conditions has been an interesting topic of study in the literature. The current article presents entropy generation assessment of a heat storage unit with a water-based nanoparticle-enhanced PCM under the impact of Lorentz forces. In this system, the nanoparticles are dispersed in the pure phase change material (water) to augment the conductive rate, speeding up the solidification (i.e., the discharging) process. For this, the governing equations are derived with impose of Darcy’s law for the permeable media and homogeneous model for the CuO–water nanomaterial features. The numerical solution method is Galerkin finite element method using FlexPDE software. The results of the simulations are presented for the entropy generation components (including friction, magnetic and thermal effects) and solid fraction contours for various Rayleigh numbers and flow conditions.

中文翻译：

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具有纳米增强相变材料并在磁力作用下的多孔结构外壳的第二定律分析

调查表明，未来的智能能源系统不可否认的一部分是储能单元，该系统将基于100％的清洁能源。实际上，由于主要的可再生能源（例如风能和太阳能）的间歇性固有特性，未来储能系统将得到高度服务。在这方面，在各种操作条件下研究组合纳米粉对通过热能存储床的PCM的热行为的影响一直是文献研究中的一个有趣课题。本文介绍了在洛伦兹力的作用下，带有水基纳米颗粒增强型PCM的储热单元的熵产生评估。在该系统中，纳米颗粒分散在纯相变材料（水）中以提高导电率，加快固化（即排出）过程。为此，根据达西定律对渗透介质推导了控制方程，对CuO-水纳米材料特征推导了均质模型。数值求解方法是使用FlexPDE软件的Galerkin有限元方法。给出了针对各种瑞利数和流动条件的熵产生分量（包括摩擦，磁和热效应）和固体分数轮廓的仿真结果。