Characteristics and potential applications of nano-enhanced phase change materials: A critical review on recent developments

Owing to incessant proliferation of challenges pertaining to energy storage systems to attain optimum design and efficient performance, massive research is underway on the development of optimal storage medium (used to overcome the low thermal storage capacity of most of the thermal transport fluids). Phase change materials (PCMs) are of the high energy storage capacity and extensively used in various applications for thermal energy storage purposes. However, the poor thermal conductivity of PCMs limits their potential in different applications. Substantial research is being conducted on the dispersion of thermally conductive nanoparticles to tackle the low thermal conductivity of PCMs. This article reviews the recent numerical and experimental studies on the nano-enhanced PCMs (nano-PCMs) to analyse the effects of nanofillers on the thermophysical properties (latent heat and thermal conductivity) of the nano-PCMs. Comprehensive details of stability enhancement techniques such as dispersant addition, sonication, and surface treatment as well as concomitant challenges along with stability measurement techniques have also been presented in this paper. Furthermore, various applications, preparation, and characterization methods of nano-PCMs are also discussed. Lastly, this review article suggests the potential research directions of nano-enhanced PCMs for the storage of thermal energy.