Refrigerator, Oil-free System, Inverter Linear Compressor
Lubricant oil is essential for lubricating moving parts and cooling the components in a refrigerant compressor. However, the oil deteriorates heat transfer performance in the heat exchangers, and increases pressure drop in a refrigeration circuit. In this study, investigation of the effects of lubricant oil circulating in heat exchangers on the performance of the domestic refrigerator-freezer was carried out by performing some experiments. The experiments were conducted for conventional and oil-less systems with using a linear compressor in an environmental chamber to compare the cooling capacity, power consumption, and operating characteristics such as temperatures and pressures at inlets and outlets of each component, mass flow rate, and cooling time. The cooling capacity and power consumption of two systems were measured during the on-off cyclic tests. Comparing the experimental data for the conventional and the oil-less systems, the discharge temperature of the oil-less system is higher than that of the conventional system more than 20℃. However, due to the oil removal, the heat transfer performance was improved and the condenser outlet temperature was measured lower than the conventional about 1℃. The power consumption of the oil-less system was reduced by about 4.0% compared to the system with the lubricant oil.