Refrigeration & Equipment Engineering

Unit 4 - Refrigerants

4.2.1.2.In-organic Refrigerants
The inorganic refrigerants were exclusively used before the introduction of hydrocarbon refrigerants these refrigerants are still in use due to their inherent thermodynamic and physical properties.

The various inorganic refrigerants are as follows

Refrigerant number	Chemical	Chemical name
R-717	Ammonia	NH3
R-744	Carbon dioxide	CO2
R-764	Sulphur dioxide	SO2
R-729	Air	-
R-118	Water	H2O

• R-717, (NH3) Ammonia
• Most widely used refrigerant
• Used in commercial reciprocating compression system and in aborption system.
• Boiling point is -33.30C
• Latent heat of vapourisation is 1315KJ/Kg (-150c)
• Poisonous, irritating to eyes nose and throat

• R-744 (Co2) carbon dioxide

• Boiling point is -73.60C
• used in dry-ice
• Non toxic, non irritating and non flammable
• Low efficiency as compared to ammonia

• R-764 (SO2) sulphur dioxide

• Boiling points-100C
• Latent heat of vaporization 396 KJ/Kg (-150C)
• Non flammable non explosive, unpleasant and irritating odour, Not injurious to food.

• R-729 (Air)

• The dry air used as a gaseous refrigerant in compression system particularly in air- craft air conditioning

• R-118 (Water)

• Use of water is as ice
• Used as a refrigerant vapour in some absorption systems and in systems with steam jet compressor
• Hydro carbon refrigerants

Hydro- carbon refrigerant
Most of the hydro- carbon refrigerant are successfully used in industrial and commercial installations. They possess satisfactory threnodynamic properties but are highly flammable and explosive. The various hydro carbon refrigerants are as follows,

Refrigerant number	Chemical name	Chemical formula
R-170	Ethane	C2H6
R-290	Propane	C3H3
R-600	Butane	C4H10
R-6009	Isobutene	C4H10
R-1120	Trichloroethylene	C2H4C13
R-1130	Dichlorethylene	C2H4C12
R-1150	Ethylene	C2H4
R-1270	Propylene	C3H6