Effect of enhanced surfaces and materials in boiling heat transfer with HFO Refrigerants: A review

Abstract

The boiling heat transfer of refrigerants on these surfaces generates more active nucleation sites and it depends on the properties of refrigerants and surface materials. Heat improvement consequence within the boiling heat transfer mainly depends on thermo-physical features of material & the working fluid, modification of surface techniques, thin-film (nano-scale, micro-scale, macro-scale surfaces, and hybrid scale), coating method, working fluid (water or refrigerants) and additives for fluids. This paper describes the current investigations on hydrofluoroolefin (HFO) refrigerants in pool boiling heat transfer. In boiling heat transfer process, a heat enhancement depends on the solid surfaces materials (surface design, surface geometry, surface material, surface finish condition), working fluid (water and refrigerants) and fluid additives, etc. Heat transfer enhancement improves the system performance of the thermal system and reduces the size of heating applications parts. In recent years, refrigerant emissions have become a serious concern as it is responsible for depleting the ozone layer. Under this circumstance, HFO refrigerants are considered as an alternative of chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). Hydrofluoroolefin (HFO) refrigerants have some excellent properties such as zero ozone depletion potential (ODP), low global warming potentials (GWP), low toxicity, mild flammability (manageable) and same system performance as HFCs for any surface tested. Based on the literature review, this paper proposed a brief future study to identify existing shortcomings.