Investigation of the effect of R134a/Al₂O₃ -nanofluid on the performance of a domestic vapour compression refrigeration system

The quest for the conservation of energy resources and production of energy systems that are more efficient have introduced the use of nanoparticles in heat transfer fluids. The study investigated the effect of Al2O3 nanoparticles on the working fluids of a vapour compression refrigeration system (VCRS) when used with refrigerant R134a. The nanorefrigerant was used in the vapour compression system without system retrofit. The system's performance analyses were carried out via the freeze capacity tests and energy consumption analysis. The outcome showed that the performance of the Al2O3-dispersed nano-working fluid outperformed that of the conventional working fluid mixture. Specifically, the outcome demonstrated that the system with the nanorefrigerant achieved faster cooling, better performance and improved energy consumption. Thus, using Al2O3 nanoparticles in combination with the working fluids of domestic refrigerators was shown to be feasible. Further to this, based on the performance results, it was necessary to find out the very reason behind the improved thermal performance of the nanoparticle dispersed working fluid. This led to the determination of the thermophysical property of the nanolubricant. The results indicate better thermal conductivity and salinity, implying that the nanolubricant has better heat transfer ability than the base oil (Capella D). In addition to this, the results of the viscosity test showed that the presence of the nanoparticles caused a reduction in the lubricant's viscosity thus portraying a reduction in the energy consumption. However, the pH test results indicate that there may be the need for an improved compressor material selection if the nanorefrigerant will be employed for vapour compression refrigeration purposes in the future.