Design and study of metal foam parameters on whole melting-solidification cycle in phase change heat storage system

In this study, the improved heat transfer properties of metal foam in a phase change heat storage (PCHS) system are studied. A 3-D transient numerical model of a horizontal square cavity PCHS unit is built to analyze the impact of metal foam (MF) on a complete melting and solidification process. An experimental PCHS system is then constructed to validate the numerical model accuracy during heat storage and release. Taguchi design method is utilized to examine the effect of porosity and pore density of MF on the total time of phase transformation, and heat charging/discharging time during complete melting and solidification. The results show that the effect of metal foam porosity on the phase transformation process is more significant than that of pore density. The melting-solidification time of Case 3 (porosity = 0.97, PPI = 30) determined by Taguchi method is 67.46 % shorter than that of Case 9 (porosity = 0.99, PPI = 30). In addition, compared with Case 9, the heat charging efficiency of Case 3 in the melting process is increased by 199.33 %, and the heat release efficiency in the solidification process is increased by 196.35 %, while the heat absorbed and released in a heat charge/heat release cycle is slightly weakened.