Performance of metal and non-metal coated phase change materials microcapsules when used in compressed air energy storage system

Abstract

Using phase change material microcapsules (PCMCs) in direct contact with a compressed air in an adiabatic compressed air energy storage system (ACAES) is an effective approach to capture the heat generated during air compression and to recover it later during decompression. In this work, three different PCMCs were investigated, including those coated with metal. The PCMCs were placed inside air-storage cylinder and compressed to 200 bar. The PCMCs stability against air compression/decompression after 20x cycles was investigated using particle size distribution analyser (PSD), differential scanning calorimeter (DSC) and scanning electron microscope (SEM). The Micronal PCMCs show better thermal storing/releasing performance than other microcapsules showing no significant changes in its thermal behaviour after 20 cycles. In terms particle size distribution, Micronal 5038X and metal-coated Microtek24D MPCMCs retained their sizes after 20 cycles. From the DSC analysis, Micronal capsules show minor reduction in heat storage capacity after 20 cycle and retained good morphology based on SEM photo.