What is the predominant oil of choice for systems using HFC refrigerant?

When dealing with HFC (hydrofluorocarbon) refrigerants, the predominant oil of choice is polyol ester. This is primarily due to the compatibility of polyol ester oils with these types of refrigerants. HFCs are generally not compatible with mineral oils because they require a lubricant that can effectively dissolve and circulate within the refrigerant.

Polyol ester oils have excellent thermal stability and can maintain their properties over a wide temperature range, which is essential for the efficient operation of HVAC systems. Additionally, they have good miscibility with HFC refrigerants, ensuring effective lubrication throughout the system. This miscibility is crucial because it allows for proper oil return to the compressor, which helps to prevent damage from oil starvation and ensures efficient system operation.

In contrast, while synthetic oil is a broader category that can include various types of lubricants, it does not specifically indicate the properties or compatibility with HFC refrigerants like polyol ester does. The other options such as mineral oil and polyethylene glycol do not provide the necessary lubrication and compatibility features that modern HFC systems require. Consequently, polyol ester is clearly the superior choice for systems utilizing HFC refrigerants.