Effect of nano-copper-structure on thermal energy storage performance of phase change materials-copper composite

Abstract

Abstract Phase change materials have been widely applied in thermal energy storage, while its applications are quite limited due to the long melting time. In the present work, the metallic 2-dimensional porous structure was probed for shortening the melting time. For straightforward prediction of melting time, a theoretical formula was firstly developed in this work, which matches the numerical results well. Then the influences of various structure characters on the heat transfer were analyzed, including the heat transfer direction, pore size, pore geometry, and volume fraction. Results turn out that: to obtain relatively short melting time, the heat-transfer direction should be parallel to the axis of the copper pore, and the pore size should be larger than 500 nm but smaller than 1 mm. The composite at nanoscale is a better choice than that at macroscale due to their larger heat storage density. In the manufacture, the pore geometry with a large sphericity is preferable for shortening melting time. This study is expected to supply some information for the selection of proper structures for a thermal energy storage system to reduce melting time.