Abstract This paper is focused on modularized concrete sensible thermal energy storage systems with thermal oil as heat transfer fluid; the thermal storage systems have been conceived to be integrated into a concentrated solar power plant. This work is mainly focused on the effect of the modules’ arrangement on the overall performance of the thermal energy storage system. Series and parallel arrangements are investigated, to determine the most performant solutions in terms of exchanged thermal energy as a function of the main operating conditions: oil mass flow rate and pressure drop, both in heating and cooling phase. Two different boundary conditions are considered: adiabatic and diabatic external walls. The simulations are carried out using an extended version of a model proposed by the present authors for a single concrete block, that was validated with experimental data. The exchanged thermal energy, the oil mass flow rate, the pressure drops, and the duration of the process are changed to evaluate the storages under different operating conditions. The best thermal energy storage configuration is determined by a thermal energy assessment: it coincides with the first one that reaches the asymptotic values with the minimum number of elements. Furthermore, in the diabatic case, the loss heat flux toward the environment has a significant role and highlights the differences between charging and discharging phases, its presence contributed to a more aware choice of the most suitable and performant modularized system.

中文翻译：

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混凝土蓄热系统的数值分析：模块布置的影响

摘要 本文研究了以导热油为传热流体的模块化混凝土显热储能系统；蓄热系统被设计成集成到一个集中式太阳能发电厂中。这项工作主要集中在模块布置对热能存储系统整体性能的影响上。研究了串联和并联布置，以确定作为主要操作条件的函数的交换热能方面的最佳解决方案：加热和冷却阶段的油质量流量和压降。考虑了两种不同的边界条件：绝热和非绝热外壁。模拟是使用当前作者为单个混凝土块提出的模型的扩展版本进行的，这是用实验数据验证的。交换的热能、油的质量流量、压降和过程的持续时间会发生变化，以评估不同操作条件下的存储量。最佳热能储存配置由热能评估确定：它与第一个达到渐近值且元素数量最少的配置一致。此外，在非绝热情况下，流向环境的热通量损失具有重要作用，并突出了充电和放电阶段之间的差异，它的存在有助于更明智地选择最合适和高性能的模块化系统。并且改变过程的持续时间以评估不同操作条件下的存储。最佳热能储存配置由热能评估确定：它与第一个达到渐近值且元素数量最少的配置一致。此外，在非绝热情况下，流向环境的热通量损失具有重要作用，并突出了充电和放电阶段之间的差异，它的存在有助于更明智地选择最合适和高性能的模块化系统。并且改变过程的持续时间以评估不同操作条件下的存储。最佳热能储存配置由热能评估确定：它与第一个达到渐近值且元素数量最少的配置一致。此外，在非绝热情况下，流向环境的热通量损失具有重要作用，并突出了充电和放电阶段之间的差异，它的存在有助于更明智地选择最合适和高性能的模块化系统。