What Is Non-Condensable Gas And Why Important To Refrigerantion System

- Sep 12, 2020-

Non-condensable gas refers to air, hydrogen, nitrogen, lubricating oil vapor, etc. mixed in the refrigeration system. These gases circulate in the system with the refrigerant, do not condense with the refrigerant, and do not produce a cooling effect.

The harm of non-condensable gas to refrigeration system

The principle of refrigeration of general refrigerators The role of the compressor is to compress the lower-pressure steam into higher-pressure steam, so that the volume of the steam is reduced and the pressure is increased. The compressor sucks in the lower-pressure working fluid vapor from the evaporator, increases its pressure and sends it to the condenser, where it is condensed into a higher-pressure liquid. After being throttled by the throttle, it becomes a higher pressure liquid. After the low liquid, it is sent to the evaporator, where it absorbs heat and evaporates to become a lower pressure vapor, and then is sent to the inlet of the compressor to complete the refrigeration cycle.

The presence of non-condensable gases will increase the condensing pressure of the refrigeration system, thereby increasing the condensing temperature, the compressor discharge temperature, the power consumption increase, and the refrigeration efficiency; at the same time, the excessive discharge temperature may cause lubricating oil Carbonization affects the lubrication effect and burns the refrigeration compressor motor in severe cases.

Causes of non-condensable gas

The non-condensable gas in the refrigeration system is mainly the leaked air. When the refrigerant and lubricating oil are filled, the outside air takes the opportunity to enter, or the system is not tightly sealed, which causes the air to enter the system. In addition, non-condensable gas may also be generated due to decomposition of refrigerating oil, impure refrigerant and corrosion of metal materials.

The main manifestation of non-condensable gas in the system

1. The discharge pressure and temperature of the compressor increase, the pressure gauge pointer on the condenser (or accumulator) swings violently, the compressor cylinder is hot, and the condenser shell is very hot.

2. Uneven frosting on the surface of the evaporator.

3. When there is a large amount of non-condensable gas, the ambient temperature cannot drop due to the decrease of the cooling capacity of the device, the compressor runs for a long time, and even the compressor stops due to the action of the high-pressure relay.

Simply put:

1. Make your car more fuel-efficient

2. Make your air conditioner not cooling

3. Let your car air conditioner accelerate the aging


1. Before the refrigeration system is charged with refrigerant, vacuum thoroughly.

2. During the operation of the refrigeration equipment, the amount of non-condensable gas in the system will also increase. This is due to the fact that the outside air enters when the refrigerant or lubricating oil is filled, or the air is not tightly sealed in the system. Enter the system. At this time, a non-condensable gas separator and discharge valve can be added to the system to discharge the non-condensable gas in the system regularly or automatically. 

Most importantly, use refrigerants with low non-condensable gas content!

The national standard for non-condensable gases in the refrigerant industry is 8 (25°C) φ/%, while the Zhejiang manufacturing standard used by Juhua refrigerant is 3 (25°C) φ/%, which is lower than the national standard.