How to Select Compressor Refrigeration Oil?

Due to the different use occasions and refrigerants, the refrigeration equipment has different choices of refrigerant oil. The requirements for refrigeration oil are as follows.

(1) Viscosity

The viscosity of refrigeration oil is an important parameter in the characteristics of oil, and different refrigerants are used to choose different refrigeration oil accordingly. If the viscosity of refrigeration oil is too large, it will increase the mechanical friction power, friction heat and starting torque. Conversely, if the viscosity is too small, it will not be able to form the required oil film between the moving parts, so as not to achieve the desired lubrication and cooling effect. (Copeland compressor)

(2) Turbidity point

The turbidity point of refrigeration oil refers to the temperature when the temperature is lowered to a certain value, and the paraffin wax starts to precipitate in the refrigeration oil, so that the lubricant becomes cloudy. The cloud point of refrigeration oil used in refrigeration equipment should be lower than the evaporation temperature of refrigerant, otherwise it will cause blockage of throttle valve or affect the heat transfer performance.

(3) Freezing point

The temperature at which the refrigerant oil cools to stop flowing under experimental conditions is called the freezing point. The freezing point of refrigerant oil used in refrigeration equipment should be as low as possible (such as the compressor of R22, the refrigerant oil should be below -55℃), otherwise it will affect the flow of refrigerant and increase the flow resistance, which will lead to the consequence of poor heat transfer effect. (Copeland compressor)

(4) Flash point

The flash point of refrigerating oil is the lowest temperature at which the lubricant is heated to the point where its vapors ignite when in contact with a flame. Refrigeration equipment used in refrigeration oil flash point must be higher than the exhaust temperature of 15 ~ 30 ℃ or more, so as not to cause the burning and coking of lubricants.

(5) Others

Such as chemical stability and oxygen resistance, moisture and mechanical impurities and insulation properties.