Experimental Investigation on Vapour Compression Refrigerator System Using Propane as Working Fluid with Graphene Oxide Nanoparticles & Pag Lubricant

Abstract

The effectiveness of different GO nanoparticle concentrations in PAG oil lubricant as a retrofit to R134a in a domestic refrigeration unit is investigated in this experimental study. In order to evaluate suction, discharge, condensing pressures, temperatures, and power utilization in compliance with ISO 8187 requirements, the test rig is outfitted with a K type thermocouple, watt-meter, and pressure gauges. Pull-down time, compressor power input, thermal conductivity, coefficient of performance, and viscosity were all evaluated as performance factors. The results revealed that all of the selected parameters of propane refrigerant infused with various concentrations of nano-lubricants reached -7°C (ISO 8187) or lesser evaporator temperatures at minimum refrigerant charges when compared to the domestic refrigerator with R134a refrigerant. All of the nanolubricant-based refrigerants shows better performance than R134a refrigerant, with COP values ranging from 2.07 with a 50-gram charge of propane using 0.6g/L GO nanolubricant to 2.67 with a 50-gram charge of propane using 0.2g/L GO lubricant. The compressor consumes 52 W (with a 50g charge of propane using 0.2g/L) and 83 W (with a 100g charge of R134a refrigerant using pure compressor oil lubricant) for all mentioned charges of GO-lubricant-based propane compared to R134a refrigerants. Furthermore, the power intake of the compressor increased at high concentrations of nanoparticles in the lubricant and dropped at low concentrations of nanoparticles in the propane refrigerant. The suction and discharge ends of the compressor for R134a with pure mineral oil lubricant had low thermal conductivity values, whereas the suction and discharge ends of the compressor for the retrofit working fluid (pure propane refrigerant and propane with various concentrations of nano-lubricants) had high thermal conductivity values.