Predictive Analysis on the Influence of Al2O3 and CuO Nanoparticles on the Thermal Conductivity of R1234yf-Based Refrigerants

Abstract

Nano-enhanced refrigerants are substances in which the nanoparticles are suspended in the refrigerant at the desired concentration. They have the potential to improve the performance of refrigeration and air-conditioning systems that use vapour compression. This study focuses on the thermal conductivity of alumina (Al2O3) and cupric oxide (CuO) nanoparticles immersed in 2,3,3,3-tetrafluoropropene (R1234yf). The thermal conductivity of nano-refrigerants was investigated using appropriate models from earlier studies where the volume concentration of particles and temperatures were varied from 1% to 5% and from 273 K to 323K, respectively. The acquired results are supported by prior experimental investigations on R134a-based nano-refrigerants undertaken by the researchers. The main investigation results indicate that the thermal conductivity of Al2O3/R1234yf and CuO/R1234yf is enhanced with the particle concentrations, interfacial layer thickness, and temperature. Also, the thermal conductivity of Al2O3/R1234yf and CuO/R1234yf decreases with particle size. The thermal conductivity of Al2O3/R1234yf and CuO/R1234yf nano-refrigerants become enhanced with a volume concentration of nano-sized particles by 41.2% and 148.1% respectively at 5% volume concentration and 323K temperature. The thermal conductivity of Al2O3/R1234yf reduces with temperature, by upto 3% of nanoparticle addition and after that, it enhances. Meanwhile, it declines with temperature, by upto 1% of CuO nanoparticle inclusion for CuO/R1234yf. CuO/R1234yf has a thermal conductivity of 16.69% greater than Al2O3/R1234yf at a 5% volume concentration. This paper also concludes that, among the models for thermal conductivity study, Stiprasert’s model is the most accurate and advanced.