Towards More Efficient Refrigeration: A Study on the Use of TiO2 and Al2O3 Nanoparticles.

Improvement of vapor-compression refrigeration systems taking into account ecological requirements will undoubtedly lead to the use of modern ozone-safe and non-greenhouse effect refrigerants. Increase of heat transfer and thermodynamic efficiency in general has raised the problem of selection of material and concentration of nanoparticles in the working mixture of refrigerant with mineral oil of compression refrigeration systems. The purpose of this study is to determine the influence of TiO2 and Al2O3 nanoparticles on the energy efficiency of refrigeration systems. Research methods: The study of operational and energy characteristics of compressor operation on the investigated mixtures was carried out on the experimental unit. Isobutane R600a refrigerant was used for the study. Efficiency is determined by power consumption, cooling capacity and efficiency. The refrigerant flow rate and nanoparticle concentration are varied during the experiment. Results: The experimental results concluded that Al2O3 nanoparticles with a mass concentration of 0.5% maximized the performance of the compressor refrigeration system. The addition of nanoparticles resulted in a significant increase in the cooling capacity, especially when compared to the original refrigeration-oil mixture with the cooling capacity parameter of 70 W. This parameter is about 79 W with the addition of TiO2 nanoparticles regardless of their concentration. When Al2O3 nanoparticles are added at concentrations of 0.1 and 0.5 wt.%, respectively, these parameters are 88 W and 102 W. [ABSTRACT FROM AUTHOR]