The article presents an experimental investigation of the charging of phase change material (PCM) inside a concentric annular cavity of horizontal and vertical heat exchangers. A heat transfer fluid (HTF) passes through the inner pipe at three temperatures of 60, 70 and 80 °C. The experimental results exhibited that conduction dominates the initial stages of the charging process. As time advances, the buoyancy-driven convection develops and speeds up the charging at the upper portion of the two heat exchangers’ orientations. It is also observed that the charging rate is influenced by the inlet water temperature and the orientation of the heat exchangers. The melting times are reduced by about 27.5%, 46.3% for an inlet temperature change from 60 to 70 °C and 60 to 80 °C, respectively, in the horizontal heat exchanger. The melting time decreases by 32.6% and 50.2% in the vertical heat exchanger for the same temperature differences. In addition, the transient Nusselt number has the same behaviour for two orientations and changes positively with an inlet temperature of HTF. Moreover, the stored energy within PCM increases with the amount of transferred energy from HTF and its temperature.

本文介绍了水平和垂直热交换器同心环形腔内相变材料（PCM）装料的实验研究。传热流体（HTF）在60、70和80°C的三个温度下通过内管。实验结果表明，传导在充电过程的初始阶段起主导作用。随着时间的流逝，浮力驱动的对流不断发展，并加快了两个换热器方向上部的充气速度。还观察到，装料速率受入口水温和热交换器的方向影响。在卧式换热器中，入口温度分别从60到70°C和60到80°C时，熔化时间分别减少了约27.5％，46.3％。在相同温度差的情况下，立式换热器的熔化时间分别减少了32.6％和50.2％。此外，瞬态Nusselt数在两个方向上具有相同的行为，并且会随着HTF的入口温度而发生正向变化。此外，PCM中存储的能量随着从HTF传递的能量及其温度的增加而增加。