Experimental and numerical investigation on enhancing heat transfer performance of a phase change thermal storage tank

Abstract

There are extensive research and application prospects in the fields of solar energy utilization and waste heat recovery of low and medium temperature latent thermal energy storage (TES), but the low thermal conductivity of phase change material (PCM) seriously weakens the thermal response rate and the rate of heat storage and release of TES. In order to solve this problem, this paper adopts a multi-scale heat transfer enhancement technique. The following parameters by grouping experiments are investigated: expanded graphite (EG) particle content, the diameter and placement position of copper rods. Then the experimental results are analyzed by the statistical response surface method (RSM). At the same time, a 3D model of the phase change heat storage of a single tank is established considering the natural convection of liquid PCM. Meanwhile, the influence of the placement of copper fin on the charging process was analyzed numerically. RSM analysis and simulation results show that copper rod diameter and EG particle content are two important parameters affecting the melting of PCM. Meanwhile, it is predicted that in the range of D Cu = 4-6mm, if the EG particle content is 2 wt.%, it has a shorter melting time and higher economic performance. The placement of the copper rod has no obvious effect on the charging process, but the placement of the annular copper fin has an obvious effect on the melting process of PCM. This study will provide guidance for the heat transfer optimization design of a single tank TES.