Experimental investigation of R600a/TiO₂/mineral oil as a drop-in replacement for R134a/POE oil in a household refrigeration system

This paper presents the coefficient of performance (COP), power consumption and the pull-down time of a domestic refrigerator using TiO₂ nanolubricant (0.4 and 0.6 g/L) in R600a refrigerant as a drop-in replacement for R134a refrigerant in a household refrigerator. The system was connected with type K thermocouples at the inlet and outlet of the major component (compressor, condenser, evaporator, expansion valve) of the system. The discharge and suction pressure are also determined by pressure gauges connected to the inlet and outlet of the compressor. The measurements output was used to determine the performance of the system using Refprop 9.0. The result showed that 0.4 g/L of TiO₂ nanolubricant has the highest COP, lowest power consumption and evaporator temperature compared to R134a in the system.