Refrigerant is a liquid used in air conditioners and refrigerators, to take heat from the contents of the refrigerator or room and dissipate heat in the earth's atmosphere. A refrigerant undergoes phase change from liquid to gas (absorbs heat) and returns to liquid (when the compressor compresses it). The ideal refrigerant choice is made based on favorable thermodynamic, non-corrosive nature, and safety (non-toxic and non-flammable) properties. Although many liquids can be used as coolants, in the 20th century, CFCs became the most popular refrigerants.
Freon R22