**Abstract**

Evolution of refrigerants has a history since the introduction of air conditioning systems by Sir Willis Carrier. The first generation air conditioning systems used natural refrigerants like air, water, carbon dioxide etc. But the need of low temperature requirements in residential and industrial air conditioning systems has forced the air conditioning field to use chloro flouro carbon type refrigerants, which was introduced by Dupon in the previous century. Physical and chemical properties of CFC type refrigerants were very good and satisfactory and so it was used in almost all refrigeration and air conditioning systems. The main disadvantage of CFC type refrigerants is harming the ozone layer and contributing much to the global warming. This chapter reviews the use of CFC type and introducing alternate type of refrigerants.

**Keywords:** Refrigerants, Chloro Flouro Carbon, Ozone, Global Warming, Emission, Environment, Alternate refrigerants
