Abstract
The results of the experimental study of the thermophysical properties of the R141b refrigerant, R141b/Span-80 surfactant solution and R141b/Span-80 surfactant/TiO 2 nanoparticles nanofluid are presented. The content of both the surfactants and TiO 2 nanoparticles in the objects of the study was 0.1 wt. %. The measurements have been performed along the liquid-saturation line in the temperature ranges of (273...293) K for the density, (293...343) K for the surface tension, (300...335) K for the kinematic viscosity, (293...348) K for the thermal conductivity and (261...334) K for the specific isobaric heat capacity. It was shown that the effect of surfactants and TiO 2 nanoparticles on the density of the R141b refrigerant was insignificant and within the uncertainty of the experimental data (up to 0.08%). Additions of both the surfactants and TiO 2 nanoparticles contributed to a decrease in the surface tension of R141b by up to 0.3% in comparison with pure R141b. Additives of both the surfactants and TiO 2 nanoparticles in R141b contributed to an increase in viscosity of (0.8...1.0) %, and additives of surfactants led to a significant decrease in viscosity – by (3.5...5.0) % compared to the viscosity of pure R141b. It was shown that surfactant additives in R141b did not significantly influence the thermal conductivity (the effect did not exceed 0.25 %), and additions of both the surfactants and TiO 2 nanoparticles lead to an increase in the thermal conductivity of the refrigerant by (0.3...1) %. A decrease of the specific isobaric heat capacity by (1.5...2.0) % was observed by adding the surfactants and TiO 2 nanoparticles to R141b. The slight increase in the specific isobaric heat capacity by adding the surfactants to R141b was observed (up to 1.0 %). It was concluded that the influence of the addition of nanoparticles and surfactants on the thermophysical properties of the R141b refrigerant is ambiguous and unpredictable. The results of experimental studies on the effect of nanoparticles on the thermophysical properties of a refrigerant confirm the importance of developing methods for predicting these properties. This method can be based on taking into account the presence of a structured phase of the base fluid or surfactant molecules on the surface of nanoparticles
Highlights
Application of nanofluids as working fluids is one of the methods to improve the vapor compression refrigeration systems performance, and reduce the costs of cold production.Nanofluids are colloidal systems containing the nanoparticles of solid metals, metal oxides, or carbon allotropic modifications
The results indicate that the nucleate pool boiling heat transfer deteriorated with increasing particle concentrations, especially at high heat fluxes
TiO2 nanoparticles are the industrial product with low cost and they are often considered by researchers as a promising additive to halogenated hydrocarbons refrigerants [4, 11, 14]
Summary
Application of nanofluids as working fluids is one of the methods to improve the vapor compression refrigeration systems performance, and reduce the costs of cold production.Nanofluids are colloidal systems containing the nanoparticles of solid metals, metal oxides, or carbon allotropic modifications. Application of nanofluids as working fluids is one of the methods to improve the vapor compression refrigeration systems performance, and reduce the costs of cold production. The nanofluids are named “nanorefrigerant” in a case the hydrocarbons or halogenated hydrocarbons (the working fluids of vapor compression refrigeration systems) are used as the base fluid. Performed in the past two decades studies have shown that the addition of small amounts of nanoparticles can significantly change the thermophysical properties of the base fluid [1,2,3,4,5,6,7,8,9,10]. The application of nanofluids as coolants and working fluids in thermal power systems (including refrigeration) can contribute to the intensification of heat transfer processes in various heat exchangers [11,12,13]. New empirical information on the thermophysical properties of nanorefrigerants is needed both for the development of calculation models for predict-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
