Hydrocarbon refrigerants as natural refrigerants are becoming increasingly more significance. In terms of environmental impact, they have significant advantages over fluorinated refrigerants. Typical representative such as R-290, R-1270, R-600a have a high thermal resistance are chemically stable and show good material compatibility. However, the main advantage is the very low global warming potential (GWP) of 3 to 6. Hydrocarbon refrigerants show good miscibility with conventional refrigeration oil types. Homogeneous mixtures are formed over a wide temperature range with both mineral oil and synthetic lubricants such as PAO or polyol esters. 
The solubility of hydrocarbons in mineral oils and other conventional refrigeration oils is relatively high, which leads to a strong dil ...