[KixxPedia] A Comprehensive Guide to Refrigeration Compressor Oil: What It Is and How It Works

If we were to name the greatest invention in human history that has reshaped our way of life and enriched our lifestyle, many would likely point to the refrigeration system used in refrigerators, air conditioners, and more. Providing both cooling and refrigeration effects, it has not only transformed how we consume food but has also contributed to a reduction in cases of fatal diseases. Life without them is simply unimaginable. 

Like most other equipment, the refrigeration system also requires lubricants for optimal performance. Refrigeration compressor oil, a special type of lubricant used for the refrigeration system, provides lubrication, wear protection and sealing and cooling effect, while also carrying the essential substance for the systems. Learn the basic mechanism of refrigeration, the importance of selecting the appropriate refrigeration compressor oil, and the latest industry trends and demands.  

How Does Refrigeration System Work?  

Before delving into refrigeration compressor oil, it’s essential to understand how a refrigeration system works. 

A refrigeration system is a system used for cooling, refrigerating and sometimes heating. Common examples include air conditioners, refrigerators and refrigerated trucks. Heat is transferred within the system and rapid temperature change occurs by compressing a chemical substance called refrigerant.  

Refrigerant is a fluid that absorbs and releases heat within the refrigeration system as it undergoes phase transfer, or the physical process of transition between one medium to another. Refrigerant goes through four stages: evaporation, compression, condensation and expansion, and cooling effect occurs during the expansion and compression process during which refrigerant turns from liquid into gas and back again. 

Refrigerant goes through the four stages of evaporation, compression, condensation, and expansion, during which it undergoes phase transition and creates cooling effect.

What is the Role of Refrigeration Compressor Oil and What is Required of it? 

Refrigeration compressor oil helps transfer these refrigerants more efficiently while lubricating and protecting machinery, especially the compressor, in high-temperature and high-pressure environments. The lubricant’s role in minimizing friction and wear and preventing oxidation is crucial because, without proper lubrication, the efficiency of the entire refrigeration system would decrease due to loss in pressure and friction caused by heat. It also provides a sealing effect, preventing the leakage of gas or liquid, as well as cooling effects, such as reducing heat caused by excessive friction. 

Refrigeration compressor oils have specific requirements to maintain system efficiency, and one crucial factor is lubricant-refrigerant miscibility, which is an evaluation of how well the refrigeration compressor oil mixes with the refrigerant. This is tested by observing the low-temperature point at which they separate, quantified as the “floc point,” and must meet the appropriate standards depending on the type of refrigerant and the hardware characteristics. The oil and refrigerant should not mix too well, as this could reduce viscosity, nor too poorly, as this could lower system efficiency.  

Other performance requirements include wear protection, thermal stability and chemical stability to protect the machinery from an extreme environment where rapid change in temperature and pressure occurs. 

Key Performance Requirements of Refrigeration Compressor Oils.

The Evolution of Eco-Conscious Refrigerants and Refrigeration Compressor Oils to Tackle Climate Issues 

During the use or disposal of the refrigeration system, refrigerants can leak, this can cause environmental contamination depending on the type of the refrigerant. One example is Freon gas, known to cause global warming. In response, many industries are making efforts to reduce the emission of greenhouse gases or other harmful substances, and this is particularly relevant in the refrigerant industry.  

The Montreal Protocol, finalized in 1987, named Freon gas (chlorofluorocarbon, CFC), well known as the first-generation refrigerant, as a substance which expedites the deterioration of the ozone layer, resulting in the phasing out of the substance in mainstream refrigerants. As a result of the gradual rise in the demand for refrigerants with minimal impact to both the climate and human health, today’s refrigerants are required to have low ozone depletion potential (ODP) and low global warming potential (GWP), while also meeting the fluorinated greenhouse gas (F-Gas) regulations.  

The refrigerant industry is constantly changing to meet the increasingly rigid climate goals.

As the refrigeration industry moves towards these eco-conscious trends, refrigerants made with hydrofluoroolefin (HFO) or other substances with minimum climate impact have now become the mainstream. Following such a shift, refrigeration compressor oils, crucial to carrying refrigerants within the system, are also going through a rapid evolution. As the types of refrigerants have expanded for greenhouse gas reduction, the need for compatibility with the increasingly diverse refrigerants has become more emphasized. 

Don’t miss our next episode, where we’ll dive into the development of Kixx RF P 85 and discover why it’s leading the way in the lubricant industry.