Which one of the following statements is correct?
In a domestic refrigerator periodic defrosting is required because frosting
Option (A)
causes corrosion of materials
Option (B)
reduces heat extraction
overcools food stuff
partially blocks refrigerant flow
Correct Option:
Question Solution:
When air is cooled below its ‘dew point temperature’, it gives up the moisture and deposits on nearest colder surface. Since the colder surface in a refrigeration area is evaporator. Therefore the moisture (in the from of dew) deposits on the surface of the evaporator. When the temperature of the evaporator fall below 0°C, the moisture freezes and from a coating of frost. If this frost is not removed periodically, it acts as an insulator and retards the evaporator which causes the compressor to run at a lower suctions, the capacity and efficiency of the refrigerating system decreases.