A comprehensive review of fundamentals, preparation and applications of nanorefrigerants

Nanofluids attract researchers in many ways for their enhanced heat transfer properties. Nanorefrigerant is one kind of nanofluids. It has better heat transfer performance than traditional refrigerants. Thermal conductivity, viscosity and density are the basic thermophysical properties that must be analyzed before performance analysis. This paper presents a comprehensive review of nucleate pool boiling, flow boiling, condensation and two-phase flow of refrigerant-based nanofluids. The effects of nanolubricants on boiling and two-phase flow phenomena are presented as well. Furthermore, studies of applications and preparation of refrigerant-based nanofluids are presented. For the limited studies done so far, there are some controversies from one study to another. Based on results available in the literatures, it has been found that nanorefrigerants have a much higher and strongly temperature-dependent thermal conductivity at very low particle concentrations than conventional refrigerant. This can be considered as one of the key parameters for enhanced performance for refrigeration and air conditioning systems. Because of its superior thermal performances, latest up to date literatures on this property has been summarized and presented in this paper as well.