Effect of charging/discharging temperatures upon melting and solidification of PCM-metal foam composite in a heat storage tube

Solar energy has addressed the significant issue of energy conservation and emission reduction through providing an alternative solution to the building energy utilization. To solve the inherent intermittency problem, latent heat phase change module is designed to even the fluctuation of energy supply. This paper designs a phase change heat storage/release unit and builds a visual test system for phase change heat storage/release. To study the influence of different heating and cooling temperatures upon thermal cycle of melting and solidification, a series of experiments are carried out. Melting front evolution, temperature field and response, and uniformity analysis are assessed. Experimental results demonstrate that the phase interface changes from top to bottom in the melting process. However, solidified covers appear evenly up and down during solidification process. Reasonably increasing the heating temperature effectively shortens the complete melting time. 56.0% reduction in full melting time is achieved if increasing the heating temperature from 65 °C to 85 °C. However, this is done at the expense of decreasing the temperature uniformity of the PCM. The results proved guidance for the design strategy on passive building energy utilization.