The heat transfer with nanomaterial enhanced phase change materials in different container shapes

Abstract

The heat transfer is studied during the melting and solidification of sp11 and sp24 phase change materials in different container shapes. The materials are further mixed with nano-alumina and nano CuO enhancements. We aim to identify the most favorable phase change material for free-cooling in summer and free-heating in winter. Ansys Fluent 20.2 is used to analyze the 2D models for the melting and solidification mechanisms of the phase change samples in cylindrical, square, rectangular, and elliptical-shaped capsules. The nanomaterial-enhanced phase change material improves the melting and solidification behavior over the base phase change material by as much as 9.8%. It is further observed that the nanomaterial-enhanced phase change material particularly in the rectangular-shaped containers has faster melting and solidification rates by over 43% compared to the others. The material sp24 with 4% nano-alumina in a rectangular profile has the shortest melting times ~70-100 mins, when the inlet temperatures are 313 and 318 K. The same material has the shortest solidification time of 426 mins, two times faster compared to the 928 mins observed with the cylindrical capsule under the same conditions. The Sp11 with the nano-alumina in a rectangular capsule also has a short melting time of 134 mins. The rectangular profile is found capable of achieving the highest temperature drop about 3.3 K during free cooling of inlet air using nano-enhanced sp24. A progress is realized in unmasking the potential of the thermal energy battery using hybrid geometry and nanomaterial enhancements.