The function of refrigeration oil in vapor compression refrigeration system is to lubricate and pressurize the compressor. When the system runs, refrigeration oil will circulate in the system with refrigerant. It is helpful to improve the lubricating ability of friction surface in compressor and heat transfer performance of refrigerant-oil mixture by adopting appropriate nano-refrigeration-oil. As a result, energy effciency and reliability of the refrigeration system will be improved. When the refrigerant c...