Thermophysical properties of Nano-enhanced phase change materials for domestic heating applications

A major problem worldwide is the increase in global energy consumption due to the drastic growth in population and requirements to meet human thermal comfort. The residential sector is one of the biggest energy consumers, and the most significant share is attributed to space and water heating. Renewable technologies are the path for a more sustainable future, and their full potential has not yet been achieved due to technical and economic limitations. The use of phase change materials (PCMs) as latent heat storage media has gained interest among researchers due to its potential and desirable characteristics to broader the deployment of renewable energies. In PCMs, low thermal conductivity is a significant drawback, and many techniques were developed to improve it. This review article mainly focuses on the processes and methods of using highly conductive nanoparticles as a thermal conductivity enhancement technique of low-temperature PCMs (temperatures from 20 to 70 °C) as a promising storage media in residential applications. The paper presents a comprehensive and up-to-date overview of the preparation methods used for Nano-enhanced PCMs (NEPCMs), the impact of nanoparticles on the thermophysical properties, stability of NEPCMs, the hybrid heat transfer enhancement techniques using nanoparticles, the promising low-temperature applications with NEPCMs, and the research gaps in the field. One of the main findings obtained from this review is that majority of the studies focused on the material properties with an application in mind, without ever studying the material in the actual application. More studies are required to be conducted, experimentally and numerically, on NEPCM domestic applications.