Experimental Investigation of Usage of POE Lubricant with Al₂O₃, Graphene or CNTs Nanoparticles in a Refrigeration Compressor

Abstract

In this study, usage of nanolubricants containing Al2O3, graphene, and CNTs nanoparticles at various mass fractions in a refrigeration compressor was experimentally investigated. Thus, the required compressor electrical power was measured to determine effects of usage of nanolubricants. Nanoparticles, which were used preparation of nanolubricant were gradually added to the lubricant to determine optimum nanoparticle mass fraction for each nanoparticle kind. Consequently, it was observed that the compressor worked safely and efficiently with nanolubricants. Additionally, optimum mass fractions were determined as 0.750% for Al2O3, 0.250% for graphene, and 0.250% for CNTs for operating conditions of this study. As a result, the required compressor electrical power decreased by 6.26, 6.82, and 5.55% with the addition of Al2O3, graphene, and CNTs nanoparticles at optimum mass fractions of 0.750, 0.250, and 0.250% to the lubricant compared to the compressor using pure oil, respectively. Furthermore, density and dynamic viscosity of the nanolubricant samples used in experiments were also measured, and their kinematic viscosity, which are an important parameter for lubricants, were calculated. It was determined that kinematic viscosity increased continuously with the increase of the nanoparticle fraction. In conclusion, nanolubricants containing nanoparticles above optimum mass fraction increase the required compressor electrical power. It is noted that nanoparticle fractions should not be used more than optimum value in the nanolubricant applications.