Methods for the Synthesis of Phase Change Material Microcapsules with Enhanced Thermophysical Properties—A State-of-the-Art Review

Thermal energy storage (TES) has been identified by many researchers as one of the cost-effective solutions for not only storing excess or/wasted energy, but also improving systems’ reliability and thermal efficiency. Among TES, phase change materials (PCMs) are gaining more attention due to their ability to store a reasonably large quantity of heat within small temperature differences. Encapsulation is the cornerstone in expanding the applicability of the PCMs. Microencapsulation is a proven, viable method for containment and retention of PCMs in tiny shells. Currently, there are numerous methods available for synthesis of mPCMs, each of which has its own advantages and limitations. This review aims to discuss, up to date, the different manufacturing approaches to preparing PCM microcapsules (mPCMs). The review also highlights the different potential approaches used for the enhancement of their thermophysical properties, including heat transfer enhancement, supercooling suppression, and shell mechanical strength. This article will help researchers and end users to better understand the current microencapsulation technologies and provide critical guidance for selecting the proper synthesis method and materials based on the required final product specifications.