Compressor Lubrication -the key to Performance

Today, Low Global Warming Potential Refrigerants are being evaluated, optimized and applied. Higher-pressure refrigerants, refrigerant blends, and new chemical families of refrigerants are candidates. Compressor designs and system components are being evaluated to deliver the desired capacity, efficiency and reliable performance for intended applications.Once the Refrigerant family is chosen based on Environmental and Heat transfer properties, System Chemistry between the Refrigerant and Lubricant families are scrutinized for optimum miscibility and solubility. These directly affect the Phase separation between the 2 liquid phases and reduction of viscosity. Over the entire Operating Envelope, the "oil return" and "viscosity reduction" problems are assessed. Compatibility aspects between chemicals (Refrigerants, Lubricants) and materials of construction (metallic, polymeric, elastomeric) are verified to avoid failures in use. System Components, compressor bearings, expansion devices and heat transfer coils are adversely affected due to contaminants circulating in systems. Rust, Copper plating, Formicary corrosion, elastomer swelling are example. Advances in Analytical Chemistry Techniques help the compressor and system manufacturers characterize the problems. Further, System Chemistry guides selection of lubricant additives.This presentation explains how lubricant selection is accomplished using Tribology and System Chemistry aspects.