Fundamentals, Thermophysical Properties, and Heat Transfer Characteristics of Nanorefrigerants: A Review

Abstract

Cooling applications that utilize latent heat property of fluids involve large heat transfer and throw more space for energy conservative research studies. Heating ventilation air-conditioning and refrigeration systems, which have now grown as an integral part in human life, circulate refrigerants and necessitate developments to become energy-efficient. The heat removal characteristics of the fluids in such large capacity systems can be enhanced using nanoparticles seeded in to them. Being smaller in size, the nanoparticles possess larger effective surface area and believed to help in expediting the conduction rate of heat from the refrigerants in the HVAC-R systems. Spectrums of nanoparticles are studied for their heat transfer behavior either in pure refrigerants or with refrigerant/oil mixtures. Suspension of the particles in the refrigerants for a prolonged time is found to be critical and must be validated prior to its implementation in the systems. Seeding of nanoparticles exclusively in a phase change fluid inside the refrigeration systems is reported to be of challenging. Additionally, to harvest the benefits of nanoscale particles, literature proposes the usage of surfactants which may lead to complex situation in a vapor compression refrigeration system. In the present work, all the relevant study details specifically on synthesis and characterization, thermophysical properties, and heat transfer characteristics about the nanorefrigerants are presented.