Compressor Designs, Lubricant Options and Refrigerant Selections: Putting the Puzzle Together

Several different compressor mechanisms varying in design, material and condition of operation are required to meet the breathe of system needs. The heart of the compressor is the mechanism designed to provide needed work of compressing and moving refrigerant. The mechanisms can vary in complexity of the main operating component and subsequent secondary mechanisms all of which are usually designed to be lubricated. The choice of refrigerant is determined by the application parameters and then usually the lubricant is chosen to meet refrigerant and lubricant interaction requirements. Even before the choice is made of refrigerant and lubricant, engineers have ideas about bearing design, material, surface finish and lubricant distribution to meet minimum film thickness constraints. This paper will focus on next generation refrigerants, compressor design and approaches along with options for successful lubricant selections. Properties and terminology such as viscosity index, working viscosity, solubility, miscibility, compression ratio and delta pressure will be utilized and understood to help put the pieces of the puzzle together.