Cooling systems No Frost and Frost Free, what is it?

Cooling systems No Frost and Frost Free, what is it?

We are talking about the defrost of the evaporator of the refrigerator. We all know perfectly well that it is impossible to operate the refrigerator with a large snow jacket on the evaporator.  Firstly, there will be a high temperature in the chamber – the products can deteriorate. Secondly, the refrigerator will consume too much electricity. So, both “No Frost” and “Frost Free” mean that the best upright freezer works without frost.

Are you going to buy a refrigerator? Have you been to the stores? Have you heard from the manager that the refrigerator has a “No Frost” system? Maybe it was “Frost Free”? And you do not know what it is and, most importantly, do you need it? Let’s figure it out.

You should not literally understand the phrase “refrigerator without frost”. The evaporator surface has a negative temperature, and the atmospheric air is always wet. In such conditions, moisture from the air will always settle on the cold surface of the evaporator and freeze. Thus, in the systems “No Frost”, “Frost Free” it is not a question of the lack of frost itself, but about the ways of defrosting the evaporator.

The  “drop type of thawing” is the most common nowadays.

In such refrigerators, the evaporator is structurally composed of two parts. The main part of the evaporator is located in the low-temperature compartment, and a small part is located in the mid-temperature compartment.

How does the evaporator defrost in such refrigerators?

The part of the evaporator is located in the low-temperature compartment, thaws traditionally. But the real need for defrosting this evaporator occurs every 4-6 months.

We know that the compressor of the refrigerator turns on periodically. There are so-called working parts and non-working parts of the cycle. In the working part of the cycle, the compressor is turned on, the evaporator takes a negative temperature and a frost is formed on it.

When the compressor is turned off, the non-operating part of the cycle, the evaporator will heat up from the air in the chamber. The moisture will flow out of the chamber into the tray above the compressor.

The defrost system of the evaporator “No Frost”. Sometimes such a defrost is called a “windy type of thawing”.

A mandatory attribute of the refrigerator with the “No Frost” system is a fan. It ensures a constant circulation of air inside the cooled volume. Warm air from the cooled volume, through special channels, is driven by the fan through the evaporator, cooled and through other channels returns to the refrigerator chamber.

 

What will happen with hoarfrost in such refrigerators? In the working part of the compressor cycle,it will intend on the evaporator. During the non-working part of the cycle, the frost, formed on the evaporator, will be thawed with a small electrical heater – TEN, and moved out of the refrigerator compartment. In some models, the defrost of the evaporator is carried out periodically – after a certain period of time – 10-16 hours – the timer switches off the compressor and turns on the heaters.

The system “Frost Free”.

In refrigerators with the defrost system “Frost Free” in the low-temperature compartment, a “No Frost” system is mounted, and in the medium-temperature one a droplet type of thawing is used.

Refrigerators with “Full no Frost” have both in the low-temperature and mid-temperature compartments SEPARATE “No Frost” evaporator defrosting systems.

Thus, the “Frost Free” and “Full no Frost” systems are characterized only by the degree of use of the “No Frost” system.

Let’s consider advantages and disadvantages of this system.

Advantage of refrigerators with “No Frost” system:

– uniform temperature regime in the cooled volume. If in the refrigerator with drip thawing the temperature difference in the height of the medium temperature chamber can reach 5-6 ° C, then with the “No Frost” system is 1-2 ° C;

– high speed of temperature recovery in the cooled volume after opening the door or loading a large number of warm products;

– a high rate of cooling and freezing products.

Disadvantages of refrigerators with “No Frost” system:

–  the shrinkage of unpackaged products increases.

–  more power to the additionally installed air cooler motor. The additional electric motor introduces additional noise and vibration.

– the technical saturation of refrigerators with the “No Frost” system leads to a certain decrease in their reliability.


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