What is Refrigerants and its Classification in Detail ?

State Board of Technical Education, SBTE

Mechanical Guruje

6th Semester, Subject - RAC 

Unit-3, Topic- Refriegrants and its type

What is Refrigerants ?

The Medium which transfer heat through the phase change during the Refrigeration process (Evaporation, Condensation, Compression & Expansion) is known as Refrigerants. Its absorbed heat from the low temperature system and exert the absorbed temperature in the high temperature system.

Natural ice and mixture of ice and salt was the first refrigerants which had used. After that ammonia, ether, Sulphur dioxide, Methyl Chloride and Carbon Dioxide also used as refrigerants.

Many firstly used refrigerant are discarded for the use due to their lack of chemical and thermal stability and also due to lack of safety.

Classification of Refrigerants :

Generally Refrigerants are classified in to two parts-

• Primary Refrigerants
• Secondary Refrigerants

What is Primary Refrigerants ?

The Refrigerants which used directly for cooling (chilling) purpose in Refrigeration Process is known as Primary Refrigerants. 

What is Secondary Refrigerants ?

The Refrigerants which first cooled (chilled) through the Primary Refrigerants and then it is used for cooling in Refrigeration Process is known as Secondary Refrigeration.

Types of Primary Refrigerants :

Primary Refrigerants also divided into four parts -

• Organic Refrigerants (Halo Carbon Refrigerants)
• Inorganic Refrigerants
• Azeotrope Refrigerants
• Hydro Carbon Refrigerants

What is Organic Refrigerants (Halo Carbon Refrigerants) :

The Halo Carbon Refrigerants are synthetically produced and its developed as feron familiy. The first Halo Carbon Refrigerants is R-12 which is developed by Thomas Midglay in 1930. There are total 42 Halo Carbon Compound are available as Refrigerants but only few are used.

What is Inorganic Refrigerants :

The Refrigerants which used before the introduction of Halo Carbon but till now used due to their inherent physical & thermal Properties is known as Inorganic Compound.

There are total 5 Inorganic Refrigerants -

• R-717 (Ammonia)
• R-729 (Air)
• R-744 (Carbon Dioxide)
• R-764 (Sulphur Dioxide)
• R-118 (Water)

What is Azeotrope Refrigerants :

Azeotrope Refrigerants is the stable mixture of two Refrigerants whose vapour and liquid phases are identical composition over a wide range of temperature. However these mixtures have differ properties from either of their components.

What is Hydro Carbon Refrigerants :

The Refrigerants which have better and satisfactory thermodynamic properties but are highly flammable and explosive is known as Hydro Carbon Refrigerants.These type of Hydro Carbon Refrigerants are used in Industrial & Commercial installation.