Comparative study of energy performance of R600a/TiO₂ and R600a/MWCNT nanolubricants in a vapor compression refrigeration system

In this paper, multiwalled carbon nanotubes (MWCNT) and TiO2 nanoparticles were dispersed in mineral oil to form nanolubricant concentration (0.4 g/L) as an alternative to pure lubricant - oil - in a domestic vapor compression refrigeration system (VCRS). The temperature and pressure measuring instruments were fixed to the compressor inlet and outlet of the system components to capture the temperature and pressure at each condition. The measured outputs of the experiment were used in determining the performances of the system using the REFPROP software version 9.0. The result showed that R600a with MWCNT and with TiO2 nanolubricants have a lower pulldown time, evaporator-air temperature, higher coefficient of performance (COP), cooling capacity with the decrease in power consumption compared to the base lubricant. The COPs of R600a in both MWCNT and TiO2 nanolubricants were higher than that of the base lubricant. The power consumption of the refrigerator compressor with MWCNT and TiO2 nanolubricants decreases within the range of 0.9-25.5% and 6.1-18.0%, respectively. Therefore, MWCNT and TiO2 nanolubricants are potential substitutes for the pure mineral oil in domestic refrigeration systems.