The principle of refrigeration is very simple! The cycle of refrigeration is used to remove the unwanted heat from a space to become desired design conditions. The equipment is used in this cycle, are capable to extract the heat and discharged it into some other place like atmosphere.   In our home, we use air conditioner, where it conditions our rooms with its principle of refrigeration. Heat is removed from the room to make it condition and discharged into the atmosphere. A medium called refrigerant is used for heat transfer from room to outside with the help of its phase changes.