The cold thermal energy storage (CTES) is of great significance for the sake of decline of fossil energy usage. However, there exhibits a low energy charging and discharging efficiency, due to the poor thermal conductivity of phase change material (PCM). In this context, the metal foam is utilized to improve the ice storage performance of the CTES device in this paper. The solidification performance of PCM in a horizontal shell-tube CTES system with fins is numerically studied with consideration of natural convection. The ice front evolutions and the dynamic temperature distribution for the case with metal foam is analyzed and compared with these without metal foam. Moreover, the influence of the porosity on the ice storage performance for the CTES system with metal foams is analyzed as well. The results imply that the addition of metal foam effectively improves the thermal performance of the CTES system, the distribution of the temperature in the shell-tube CTES system is more uniform and the freezing speed of PCM is faster due to coupled effects of thermal conduction enhancement and the suppression of the natural convection. The porosity of the metal foam plays an essential role in the ice storage performance of the CTES system. The smaller porosity of the metal foam induces faster freezing speed and more uniform temperature distribution. Therefore, a smaller porosity is recommended for faster energy discharging rate in practical engineering applications.

中文翻译：

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金属泡沫对冷热能储存（CTES）系统冰储存性能的作用

冷热能储存（CTES）对于减少化石能源的使用具有重要意义。然而，由于相变材料（PCM）的导热性差，其能量充电和放电效率较低。在此背景下，本文利用泡沫金属来提高CTES装置的蓄冰性能。在考虑自然对流的情况下，对带翅片的水平壳管式 CTES 系统中 PCM 的凝固性能进行了数值研究。分析了有金属泡沫情况下的冰锋演变和动态温度分布，并与没有金属泡沫情况进行了比较。此外，还分析了孔隙率对泡沫金属CTES系统蓄冰性能的影响。结果表明，泡沫金属的添加有效提高了CTES系统的热性能，由于热传导增强的耦合作用，壳管式CTES系统内的温度分布更加均匀，相变材料的冻结速度更快。以及自然对流的抑制。泡沫金属的孔隙率对 CTES 系统的蓄冰性能起着至关重要的作用。泡沫金属的孔隙率越小，冷冻速度越快，温度分布越均匀。因此，在实际工程应用中，建议较小的孔隙率以获得更快的能量释放速率。