Influence of Refrigerant Type, Nanoparticle’s Concentration and Size on the Performance and Exergy Efficiency of the Vapour Compression Refrigeration System Using Al2O3 Based Nanolubricant

Vapour compression refrigeration systems (VCRS) are commonly used in the tropic region for the cooling and preservation of household and industrial items. The performance, power consumption and exergy efficiency of the vapour compression refrigeration system (VCRS) can be improved by replacing the lubricant with nanolubricants. In this study, nanolubricants were prepared at different mass concentrations of 1%, 3%, 5%, 10%, and 20% using aluminium oxide (Al2O3) nanoparticles of nominal diameter 10 nm, 20–30 nm and 80 nm. Scanning electron microscopy (SEM) and X-ray diffraction analyses were carried out on the aluminium oxide (Al2O3) nanoparticles. Using R600a and R134a refrigerants to investigate heat transfer behaviour of nanorefrigerant, the addition of nanoparticles into the VCRS enhanced the performance and exergy efficiency of the system. This was achieved by reducing the energy consumed and destroyed within the compressor of VCRS. Smaller nominal diameter nanoparticles of 10 nm performed better and possess better exergy efficiency for nanoR600a while the 20–30 nm had the best performance for nanoR134a refrigerant. The average value of coefficient of performance (COP) obtained was observed to be higher for R600a using 10 nm sized nanoparticles compared with R134a.