Defrosting :- Due to very low temperature, below freezing (upto -23 deg.cel) in evaporator small white crystals of ice start to accumulate over the surface of evaporator and make formation of solid ice. To melt this ice a defrosting system is installed in refrigeration system. This defrosting system automatically sense the ice formation of ice and start to increase the temperature on the evaportor coil. When ice melts down completely it stops to heat the evaporator coil and refrigeration cycle automatically starts once again. In old refrigerators a switch with red color near the ligting bulb, inside the refrigerator was provided to manually defrost the refrigerator.
If defrosting switch is not provided, air circulation through the coil will be stopped by ice formation and cooling may not happen in whole refrigerator.
Defrosting systems are classified as below :-
1. Mechanical defrosting system
2. Electric defrosting system
1. Mechanical defrosting :- In this defrosting system a solenoid valve is provided in the refrigeration piping circuit. At the time of ice formation this solenoid valve gets energized and open the valve which by pass the expansion valve or cappillary tubes and refrigerant coming from condenser at high temperature and pressure directly passes through the evaporator and ice starts to melt.
2. Electric defrosting system :- In this system a electric heater is provided on the evaporator fins and it automaitically works with a sensor on coil. This heat usually looks likea coil but it only a electrical heater with proper insulation to provide leak proofing. This heater is connected to a timer which can be adjusted manually.
If defrosting switch is not provided, air circulation through the coil will be stopped by ice formation and cooling may not happen in whole refrigerator.
Defrosting systems are classified as below :-
1. Mechanical defrosting system
2. Electric defrosting system
1. Mechanical defrosting :- In this defrosting system a solenoid valve is provided in the refrigeration piping circuit. At the time of ice formation this solenoid valve gets energized and open the valve which by pass the expansion valve or cappillary tubes and refrigerant coming from condenser at high temperature and pressure directly passes through the evaporator and ice starts to melt.
2. Electric defrosting system :- In this system a electric heater is provided on the evaporator fins and it automaitically works with a sensor on coil. This heat usually looks likea coil but it only a electrical heater with proper insulation to provide leak proofing. This heater is connected to a timer which can be adjusted manually.
