Primary refrigerant :-

• Primary refrigerant are those refrigerant fluid, which are directly used in refrigerant.

• Primary refrigerant is cooled the substance or specific area directly by absorbing latent heat. i.e this refrigerant directly absorbs heat.

• When primary refrigerant system used in refrigeration system then that system is called as directed expansion system.

• Primary refrigerant fluid is directly used in refrigerant that means no any chemicals process used before primary refrigerant used in refrigerant.

• Primary refrigerant fluid provides refrigeration by undergoing the phase change in evaporator.

Primary refrigerant examples -

• Ammonia
• Feron
• Carbon dioxide (Co2)
• SO2
• Water

Selection of primary refrigerant depends upon -

• Properties of refrigerant, like flammability, toxity, reactivity, chemical stability etc.
• Environment acceptability like Average life, Global warming potentical, Ozon depletion potential
• Cost and efficiency of refrigerants

Secondary refrigerant :-

• Secondary refrigerant are those refrigerant fluid, which are not directly used in refrigerant.
• Secondary refrigerant is cooled the primary refrigerant. i.e secondary refrigerant heat absorption from primary refrigerant.
• Secondary refrigerant is liquid that used for transforming energy from primary refrigerant.
• Secondary refrigerant fluid is not directly used in refrigerant.
• Secondary refrigerant fluid provides refrigeration without the phase change in evaporator.
• Secondary refrigerant are those liquid which transform thermal energy from one place to another place.

Secondary refrigerant examples -

• Brines
• Water
• Air