An experimental approach to study thermal and tribology behavior of LPG refrigerant and MO lubricant appended with ZnO nanoparticles in domestic refrigeration cycle

Abstract

The present article experimentally examines the application of ZnO nanoparticles in refrigeration cycle. Nanoparticles overcome the energy consumption issue by improving the compressor lubrication characteristics. In this study, the ZnO nanolubricant is proposed as a promising lubricant to improve the lubrication characteristics of domestic refrigerator compressors. Effect on compressor suction-discharge characteristics as well as energy consumption of refrigeration cycle has been observed using ZnO nanoparticles with pure refrigerant (Liquid Petroleum Gas). The physics involved behind the communication of nanoparticles with base refrigerant has been more clarified by performing tribological tests (i.e., measurement of viscosity and friction coefficient) of compressor lubricant for dissimilar fractions of nanoparticles. Thermal conductivity test on lubricant with distinct fractions of nanoparticles has also been conducted. The results showed that ZnO nanoparticles additive in mineral oil increases the viscosity which leads to a significant reduction in friction coefficient inside the compressor piston cylinder assembly which leads to a significant improvement in compressor energy consumption. The friction coefficient of nanolubricant with fraction of 0.7 g/L are about 11.1–25% lower than that of base lubricant. The compressor energy consumption was saved about 0.44–10% for employing ZnO nanolubricant with a mass fraction about 0.1 g/L to 0.7 g/L. Thermal conductivity was significantly enhanced (about 41%) using ZnO nanoparticles in mineral oil. The results of the present study assure better, effective and suitable performance of LPG as alternative refrigerant in refrigeration cycles.