Preparation and Performance of Highly Conductive Phase Change Materials Prepared with Paraffin, Expanded Graphite, and Diatomite

Abstract

Low thermal conductivity of phase change materials (PCM) leads to low discharge powers of heat storage. In this paper, the thermal conductivity of paraffin is enhanced by expanded graphite and diatomite. A series of highly conductive phase change materials is prepared. The content of paraffin is as much as 70% by wt. and no leakage liquid was observed even when the temperature is over paraffin's melting point. The thermal characteristics such as melting point and latent heat of the prepared PCM were determined by Differential Scanning Calorimetry (DSC). In addition, the heating and cooling curves of the prepared PCM were measured to investigate their storage–release rate. The experimental results show that expanded graphite with porous structure not only adsorbs PCM but also greatly enhances the thermal properties of PCM.

Keywords:

• Phase change materials (PCM)
• Thermal conductivity
• Expanded graphite
• Diatomite

ACKNOWLEDGEMENT

The authors gratefully acknowledge the financial support for this research by National Natural Science Foundation of China (50808042), 11th Five Years Key Programs for Science and Technology Development of China (2007BA000875-04), the Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, Jiangsu Province “Six Talent Peak” Higher-Level Talent Project (1112000053), and Research Program for Excellent Young Teachers of Southeast University.