Energy storage with PCM in fluidized beds: Modeling and experiments
Energy storage with PCM in fluidized beds: Modeling and experiments
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DOI：
10.1016/j.cej.2014.11.107
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发表时间：
2015-03
影响因子：
15.1
通讯作者：
M. A. Izquierdo-Barrientos;C. Sobrino;J. A. Almendros-Ibáñez
中科院分区：
文献类型：
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作者：
M. A. Izquierdo-Barrientos;C. Sobrino;J. A. Almendros-Ibáñez
近年来，由于相变材料的高潜热和高储能密度，相变材料的发展为提高系统的储能能力提供了新的途径。这项工作的目的是模拟以相变材料作为储能装置的沸腾床的充填过程。利用流态化两相理论对流态化加料过程中的床层温度进行了模拟。密相被认为是完全混合的，气泡相被认为是推流。该数值模型考虑了床料的相变过程在一定温度范围内发生的事实，并估算了床壁和分布板中储存的能量。考虑了在一定温度范围内发生相变时，相变对温度的依赖关系，以焓的形式数值求解了稠相的能量方程。用两种颗粒材料的实验数据验证了模型的有效性：沙子是一种典型的流态化材料，而颗粒相变材料的平均粒径为0.54 mm，相变温度约为50℃。对于沙子，数值计算得到的温度分布与实验测量值非常吻合。对于粒状相变材料，选择较慢和相似的升温速率进行实验，以及用DSC测量来确定相变材料的热焓-温度曲线时，曲线的拟合度较好。
In recent years, the development of phase change materials (PCMs) has introduced new ways to increase the energy storage capacity of a system due to the high latent heat and high storage density of these materials. The aim of this work is to model the charging process of a fluidized bed with PCMs operating as an energy storage device. The temperature in the bed during the charging process of the fluidized bed has been modeled using the two phase theory of fluidization. The dense phase is taken to be perfectly mixed, and the bubble phase is taken to be in plug flow. The numerical model presented takes into account the fact that the phase change process of the bed material occurs over a temperature range and also estimates the energy stored in the wall of the bed and in the distributor plate. The energy equation of the dense phase is numerically solved in enthalpy form, considering the dependence of enthalpy on temperature for phase changes occurring over a range of temperatures. The model’s validity is verified against experimental data for two granular materials: sand, a typical material used in fluidized beds, and a granular PCM with a mean particle diameter of 0.54 mm and a phase change temperature of approximately 50 °C. For the sand, the temperature profiles obtained numerically perfectly agree with the values measured experimentally. In the case of the granular PCM, the fitting of the curves is improved when slow and similar heating rates are selected for the experiments and for the DSC measurements used to determine the PCM enthalpy–temperature curve.