Numerical and experimental study on the effect of metal wire matrix on the melting heat storage efficiency of n-octadecane heated from below

Abstract

Phase change materials (PCM) enhanced with a metal wire matrix improve energy storage efficiency. However, the interplay between enhanced thermal conduction and suppressed natural convection (NC) during the melting process remains inadequately understood. This paper presents a systematic numerical analysis of the influence of metal wire on heat storage efficiency by improving thermal conductivity, reducing NC, and altering the melting mode. The accuracy of the analysis was validated by comparison with experimental melting results. The results show that the high thermal conductivity channel constructed by the 5 × 5 metal wire can reduce the TMT reduction radio to 40.2 %. Under the competition between thermal conduction and NC, the heat storage efficiency initially decreases and then increases with the increase of metal wire cells, with the 2 × 2 metal wire structure showing the lowest efficiency. Similarly, with increasing metal wire wall thickness, the effect on energy storage efficiency initially shows suppression and then enhancement. By analyzing these effects, the critical wall thickness for various metal wire configurations were determined, providing parameter support for the design of metal wire enhanced PCM.