by Maryam Hussain
Why do refrigerators’
compressor runs for longer durations & waste electrical energy?
Required compartment
temperatures:
The ideal temperature inside (the
lower section of) a refrigerator is between 36˚ and 38˚ F. For a freezer, the
temperature should range between –5˚ and 5˚ F.
If you think that your
refrigerator and freezer are too warm or too cold, test them by putting a
thermometer in the refrigerator and freezer cabinets for a couple of hours
each, and check the readings. If they’re high or low w.r.t above mentioned
ranges, adjust the temperature controls up or down to reach the correct
temperature. If the temperature controls don’t fix the problem, further
troubleshooting is required.
Leaky gaskets of a
refrigerator door:
The doors of the refrigerator and
freezer of your unit are fitted with rubber gaskets to seal the cold air
inside. If the gasket is worn out, the compressor has to work with overtime to
keep up, which increases the electricity bill and decreases the health of the
compressor. Check the seal for cracks or other damage by holding a thin
glazing paper or thin polythene piece at the door’s edge, and close the
door. Then pull the paper out; You should feel the gasket gripping the paper.
If it slips out without resistance, the gasket may need to be replaced. Consult
a technician for replacement.
Restarting the fridge after
shutdown and repair:
After installation of the new gasket,
recheck the integrity of the seal by the method explained above and note the
ambient temperature.
Now ensure that the fridge is
empty, and the temperature controller is set at the 3rd or
4th position then start the fridge and note the time.
After the compressor stops automatically, note the compressor operation time
interval.
Now place the food items
such that hotter items are placed on lower racks & colder ones on upper
racks. Then find again the compressor operation time interval. Now these two-time
intervals are your reference readings at the noted ambient temperature. If
the compressor operation time remains about the same at about the same ambient
temperature, then it is all is well!
Why & how to clean the
condenser of a refrigerator?
The mankind invented a
refrigerator to cool a refrigerated space or to maintain the temperature within
a dwelling below that of the surroundings in order to provide comfort to
mankind. In a refrigerator, the inside compartment acts as the cold body,
and the ambient air surrounding the refrigerator is referred to as the hot
body. There are four major components of a refrigerator;
Cabinet of the refrigerator:
1). A cabinet that maintains a
temperature well below the outside temperature. This cabinet is made of heat-insulating
materials that help reduce the heat transfer rate from an outside hot
environment to an inside cold environment. This cabinet is usually divided into
two compartments. One is called a freezer and the other is merely called a
refrigerator.
Compressor for pump the
refrigerant:
2). A compressor, like a pump,
moves the refrigerant through all components of the refrigerator by compressing
the refrigerant to a relatively high pressure and temperature, therefore a
compressor is usually hot and is located outside of the cabinet of a
refrigerator.
Condenser for rejecting heat
of food stuff to the surroundings:
3). Next, the refrigerant passes
through the condenser, where the refrigerant condenses and there is heat
transfer from the refrigerant to the cooler surroundings. Condenser tubes have
temperature gradients and are naturally cooled. Condenser is located at the
rear outside of the cabinet and is usually black in color to radiate heat to
the environment in addition to supporting conductive-convective heat transfer
modes. Its external fouling increases resistance to conduction & radiation
heat transfers.
Capillaries for cooling the
refrigerant:
4). Finally, the highly pressurized and condensed refrigerant enters a thin throttling capillary that reduces the pressure of the refrigerant significantly and gives a significant cooling effect (Joule-Thomson effect). This component is also located outside of the cabinet component.
Clean the condenser coils of a
fridge:
Every domestic refrigerator is
fitted with a network of condenser coils at its rare side. Removing dust and
spider webs from it improves the heat rejection to the outside of the
refrigerator and returns the desired cooling in a reduced time interval.
Cleaning the coils once a year saves energy and helps the
refrigerator last longer.
To start the job, unplug the
refrigerator from the electric supply. Roll the refrigerator away from the
wall. Smoothly & gently rub the coils with a medium-sized soft and
dry paint brush from top to bottom direction. Prepare a detergent-water mixture
and smoothly & gently rub the coils with it via the same brush. Then rub
the coil, once or twice, with neat water and washed brush. Clean the floor,
roll the fridge back into position. Wait for about 30 minutes to settle any
tilted compressor oil & to allow the water to evaporate from the
condenser, compressor, junction box etc.
Now plug the refrigerator. Keep the condenser coils one foot away from the wall. Restart the fridge as per guidelines.
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