Test: Refrigerants - 1 - Mechanical Engineering MCQ

Desirable properties of an ideal refrigerant:
-Low boiling point
- High critical temperature
- High latent heat of vaporization
- Low specific heat of liquid
- Low specific volume of vapour
- Non-corrosive to metal
- Non-flammable and non-explosive
- Non-toxic
- Low cost
- Easy to liquify at moderate pressure and temperature
- Easy of locating leaks by odour or suitable indicator
- Mixes well with oil

A single atom of Cl released from CFC reacts taking out 10⁵ O₃ molecules.

Ammonia (NH)₃
Reciprocating & screw compressors Cold storages ice plants, Food refrigeration
Water (H₂0)
Water-lithium bromide Steam ejector system only for air-conditioning
R-12
Reciprocating compressors in small unit Domestic refrigerators, water coolers
CO₂
Frozen-food transport refrigeration
R-11
Used with centrifugal compressors in large capacity central air-conditioning plants.

For ammonia leaks, a burning sulphur taper is used which in presence of ammonia forms white fumes of ammonia sulphate

An electronic leak detector is most sensitive and is used in the manufacturing and assembly of refrigerant equipment. The operation of the instrument depends on the flow of current due to the ionization of the leakage gas between two opposite-charged platinum electrode.