Thermodynamic analysis of an air conditioner using R22/HC blend with TiO2/Mineral oil nanolubricant to retrofit R22/POE oil

Abstract

This research was performed experimentally and determined the first and second law performance (energetic and exergetic) of a split type air conditioner. A blend of R22 and R600a (80:20 by mass) was used as a refrigerant with TiO2/Mineral oil (MO) as a lubricant for a varied concentration of TiO2 (0.1–0.4%) as a drop-in replacement of R22/POE. The obtained data were analyzed to investigate the thermodynamic performance including compression work, compressor discharge temperature, cooling effect, coefficient of performance (COP), and exergy destroyed in the compressor, total exergy destruction, sustainability, and exergy efficiency. The analysis was based on temperature, pressure readings recorded from the appropriate gauge, and the physical and thermal properties of the refrigerants were extracted from REFRPROP 7.0 software. Experimental outcomes showed that both energetic and exergetic performance was improved for a blend with nanolubricants compared to R22. The compressor outlet temperature was found to be decreased by 15 ​°C for the blend with 0.4% TiO2/MO nanolubricant. Again, COP was improved by 10–19.5% for the various concentration of nanolubricant. The exergetic performance was also increased with the increase of concentration of nanolubricants and exergy destruction was reduced by 20.1–37.4% for the nanolubricant. It was found that exergy efficiency was also increased by 38–42.88% compared to R22. Also, exergy destruction and entropy generation were found to be maximum for the compressor compared to other components. Based on this experimental work, it can be concluded that nanolubricant and refrigerant blends worked safely without any modification in this system.