R22 is a refrigerant with the chemical name of chlorodifluoromethane, which is commonly used in air conditioners and other refrigeration equipment. If your air conditioner is more than ten years old, it is likely to use R22 refrigerant, that is what we often call Freon. In the past, R22 was frequently detected in both residential and commercial air conditioners.
Although it was later found that R22 is destructive to the ozone layer and will make it thinner, it still plays an important role in the refrigeration industry.
R22 refrigerant needs a high latent heat of vaporization so that it can produce good cooling effect at a moderate circulation rate. In each refrigeration cycle, it can absorb and reject more heat.
Employing R22 refrigerant necessitates a smaller compressor and lower compressor motor power due to the high gas density at the compressor suction port. R22 does not expand very much after passing through the evaporator, which means that the degree of volume increase when it changes from liquid to gas is moderate.
A larger refrigerant mass flow rate will reduce the circulation rate in the system, so the compression ratio of the compressor will be lower.
R22 is non-flammable, non-corrosive, and non-toxic, so it unlikely do harm air conditioners, human health, or food. Metal components, however, cannot be electrochemically corroded by it. It must be compatible with non-metallic parts, such as nitrile rubber tubes and O-rings.
When R22 refrigerant is compressed at high pressure and temperature in the compressor, it cannot explode or catch fire in the system and must remain non-flammable.
If there is water in the system, highly corrosive chemicals, usually acids, will be produced, which will react with the compressor lubricant and other elements in the system, including metals.
R22 has a relatively low ozone depletion potential of 0.055, which is the lowest among chlorinated halides. Therefore, it is often used to replace refrigerants that are more harmful to the ozone layer, such as CFC-11 and CFC-12.
However, R22 itself is a greenhouse gas with a particularly high global warming potential of 1,810 ℉, which means that its greenhouse effect is 1,810 times that of carbon dioxide. Because hydrofluorocarbons (HFCs) have lower ozone depletion potentials, HFCs are often used to replace R22, even though HFCs have high global warming potentials.
R22 is also an important raw material in commercial organic fluorine chemistry, such as in the manufacture of tetrafluoroethylene. R22 cylinders are bright green. However, because of the ozone depletion potential and high global warming potential of R22, developed countries are phasing it out. However, demand for R22 is still increasing in some other places, so global use of R22 continues to grow.
