CFD simulation of a TES tank comprising a PCM encapsulated in sphere with heat transfer enhancement. (October 2018) - Aziz, S.
Highlights: Thermal enhancement for PCM in sphere were studied by both simulation and experiment. CFD simulation procedures on TES with PCM sphere are well presented in this paper. Pins and copper plating were employed to enhance the heat transfer rate of PCM sphere. For sphere with pins design, PCT was reduced by 27% relative to a plain PCM sphere. Copper coating sphere with pins reduced PCT by 37% relative to a plain PCM sphere. Abstract: Phase change materials (PCMs) are known to have a critical drawback of low thermal conductivity that resulted to an ineffective thermal storage system. This paper aims to investigate the effect of the heat transfer enhancement in a thermal energy storage (TES) system comprising a PCM encapsulated in sphere. To enhance the performance, the design modification method by the employment of pins and copper plating were adopted and carried out by computational fluid dynamics (CFD) and experimental studies. The phase change times (PCTs) of the systems were analysed as a performance measure. Consistent with the experimental results, simulation analysis in ANSYS CFX showed that utilising pins for heat transfer enhancement reduced the PCT of the PCM by 27% while design modification with copper coating and embedded pins reduced the PCT by 37% relative to a plain sphere. Good correlation of the PCT was found between the graphs plotted from CFD analysis and experimental data. This study prescribes that the CFX model developed can accurately predict the PCM behaviour of the sphere, with and without modification. These improved results facilitate the use of a conductor and copper plates as an alternative technique for the performance improvement of a PCM encapsulated in a sphere.