LAUSR

Abstract This paper experimentally investigated low concentration of TiO 2 , SiO 2 and Al 2 O 3 nanoparticles dispersed in a mineral oil lubricant, in a domestic refrigerator system, using LPG as the working fluid. The performance of the system was investigated with test parameters including: power consumption, thermal conductivity and viscosity at the suction and discharge end of the compressor, evaporator air temperature (pull-down time) was also considered. Findings showed that all nano-lubricant based LPG had lower steady state evaporator air temperatures than LPG with pure mineral oil at 180 min. In addition, TiO 2 and SiO 2 nano-lubricants gave 13 and 12% reductions in power consumptions than the base refrigerant (LPG), whereas higher power consumption of the refrigerator system was found with utilization of Al 2 O 3 -lubricant when compared with base refrigerant (LPG). Futhermore, error analysis conducted using Mean Absolute Bias Error (MAPE) and Root Mean Square Error (RMSE) showed that Al 2 O 3 -lubricant gave the best fit with pure-lubricant LPG than TiO 2 and SiO 2 . Application of nanoparticles in refrigeration systems was found to improve the performances of the system, but TiO 2 followed by SiO 2 will be prefered among the nanoparticles, as Al 2 O 3 -lubricant was found to be incompartible with hydrocarbon refrigerant having led to a high power consumption.