Many owners of refrigeration equipment are wondering about the possibility of repurposing their device, especially at times when there is an urgent need to freeze a large volume of food or a separate chest freezer has broken down. It would seem that logic dictates that if the unit cools down to +4°C, then it should also cope with lower temperatures with proper settings. However, the physics of the operation of compression systems and thermodynamics dictate their own strict rules that cannot be ignored.
Technically standard refrigerator is not intended for operation in deep freezing mode, since its heat exchangers and refrigerant are designed to maintain positive temperatures. Trying to force the device to operate at its maximum capacity can lead to serious breakdowns, failure of expensive components and food spoilage. It is important to understand where the line is between an emergency measure and constant operation.
In this article we will analyze in detail the design features of refrigerators, explain why they cannot become full-fledged freezers, and consider exceptions to the rules. You will learn about the risks associated with working thermostat and compressor in abnormal modes, and also receive answers to frequently asked questions.
Fundamental differences in temperature modes
The main difference between the refrigerator and freezer compartments lies in the target temperature and, as a consequence, in the design of the heat removal system. The refrigerator compartment designed for short-term storage of products at temperatures from +2°C to +6°C. In this range, biological processes slow down, but the water remains in a liquid state, which preserves the structure of the tissues of vegetables and fruits.
In turn, freezer compartment should provide a temperature of -18°C and below. This is critical for long-term storage, since at such values the water in the products crystallizes, turning into ice, which completely stops the activity of bacteria. A difference of 20-25 degrees seems insignificant only on paper, but in thermodynamics it requires a completely different approach to thermal insulation and compressor power.
If you try to set the thermostat of a regular refrigerator to the lowest possible value, the internal temperature may drop to 0°C or -1°C. However, stable maintenance of -18°C cannot be achieved due to design limitations evaporator. It is simply not capable of removing heat with the intensity required to freeze a large volume of food.
In addition, the humidity in the refrigerator compartment is higher than in the freezer. When trying to freeze, the products will be covered with frost, but they may remain thawed inside, which will lead to the proliferation of pathogenic microflora. A critical mistake is to assume that if a product is hard to the touch, then it is safely frozen for long-term storage.
Design limitations of household refrigerators
Engineers design refrigerators designed for a certain range of loads. Heat exchangerlocated inside the refrigeration chamber (often this is the back wall or hidden element), has a limited area. The freezer requires more powerful radiators and forced air circulation, which is implemented in freezer systems, but is rarely found in the main compartment of the refrigerator. No Frost freezers, but is rarely found in the main compartment of the refrigerator.
Another important element is thermostat (thermostat). In conventional models, its calibration is configured to open the compressor power circuit when it reaches +3...+4°C. Even if you turn the knob to maximum, the mechanical limit may not allow the temperature to drop below -2...-4°C. Electronic control modules also have software restrictions that do not allow them to go into deep minus.
⚠️ Attention: Long-term operation of the compressor without shutting down (cycling) leads to overheating of the motor windings and burnout of the starting relay. Do not try to “deceive” the thermostat by jamming its contacts.
It is also worth considering the thickness and quality thermal insulation of the walls. In the refrigerator compartment, it is designed to maintain cold when the temperature difference with the environment is about 20 degrees. For a freezer where the delta is 40-50 degrees, a thicker layer of polyurethane foam is required. Otherwise, the compressor will work continuously, trying to compensate for heat inflows.
The impact on the operation of the compressor and refrigerant
An attempt to use a refrigerator as a freezer creates extreme conditions for compressor. This is the heart of the system, which circulates the refrigerant throughout the circuit. In normal mode, the compressor operates cyclically: it turns on, cools the chamber, turns off, and rests. When trying to reach low temperatures, the operating time increases and the rest time is reduced to zero.
Under such conditions refrigerant (freon) may not have time to completely evaporate in the evaporator and return to the compressor in a liquid state. This phenomenon is called “hydraulic hammer” and is fatal to the piston group. The liquid does not compress, which leads to valve failure or motor jamming.
Lubricating oil circulating along with freon can thicken in the circuit at low temperatures, losing its properties. This leads to increased friction and wear of parts. If your refrigerator uses an inverter compressor, the electronics may block operation when abnormal loads are detected, but older models will work “until victory,” that is, until they break down.
- 🔥 Overheating: The motor windings may not withstand prolonged load, which will lead to an interturn short circuit.
- ❄️ Freezing: Moisture from the air will actively condense and freeze on the elements, disrupting heat transfer.
- 📉 Falling efficiency: The efficiency of the system will drop sharply, and electricity consumption will increase by 2-3 times.
Rules storing food at low temperatures
Food safety directly depends on temperature conditions. In the zone freshness or zero chamber, the temperature is kept around 0°C, which allows you to store meat or fish for several days. However, for freezing it is necessary to quickly pass through the crystallization zone so that small ice crystals are formed that do not destroy the cells of the product.
A conventional refrigerator cools slowly. As a result, large ice crystals form inside the piece of meat, which tear the fibers. After defrosting, such a product will lose juice and become dry and tasteless. Moreover, slow freezing does not guarantee the death of all bacteria; some of them simply fall into suspended animation.
There are special zones, for example Super Cool or the “Deep Freezing Zone” at the top of single-chamber refrigerators. There the temperature can drop to -6...-8°C. This is suitable for short-term storage (several days) or pre-freezing, but not for long-term supplies.
It is important to remember about the product proximity. If you do decide to freeze food, isolate it from other odors. At low temperatures, volatile substances spread differently, and milk can absorb the smell of fish even in a closed package if it is not sealed.
Is it possible to reconfigure the thermostat or sensor?
Theoretically, a mechanical thermostat can be replaced with a model with a lower shutdown threshold. However, such a procedure requires deep knowledge in the field of refrigeration technology. It is necessary not only to change the sensor, but also to recalibrate the system, and also make sure that the remaining components will withstand the new conditions.
In modern electronically controlled refrigerators control module (board) has hard-wired algorithms. Even if you replace the temperature sensor with one that shows lower values, the controller logic will not command cooling below the minimum set by the software. Bypassing these limitations is only possible by flashing the firmware, which is impossible under domestic conditions and will void the warranty.
| Parameter | Refrigerator compartment | Freezer compartment | Risk of reconfiguration |
|---|---|---|---|
| Temperature | +2...+6°C | -18...-24°C | High |
| Humidity | High (up to 90%) | Low | Icing |
| Cyclicity | 30-40% of operating time | 60-80% of operating time | Wear compressor |
| Thermal insulation | Standard | Reinforced | Continuous operation |
Independent replacement of the thermostat with a “colder” analogue can lead to that the refrigerator will turn off, for example, at -10°C. But, as we found out, structurally it will not be able to achieve even this value stably. As a result, you will end up with a wasted compressor and spoiled products.
☑️ Check before the experiment
Comparison of single-chamber and double-chamber models
In single-chamber refrigerators the freezer compartment (freezer) is usually located at the top and separated from main chamber with a plastic door or flap. Here, freezing occurs precisely in this small compartment where a separate evaporator is installed. The main chamber in such models will never become a freezer.
Two-chamber models have independent circuits or an air distribution system. In systems Total No Frost one powerful evaporator is located in the freezer compartment, and cold air is forced by a fan into the refrigerator compartment. Theoretically, if you close the air supply channels to the upper chamber and direct all the cold there, you can get the effect of a freezer, but this will upset the balancing of the system.
There are models with the function Holiday Mode (Vacation), which maintain a temperature in the fridge compartment of about +10...+15°C to save money energy. This is the opposite of what we need. Some premium brands offer a feature that temporarily lowers the temperature in the freezer, but this is also not designed to turn the refrigerator compartment into a freezer. Power Freeze, which temporarily lowers the temperature in the freezer, but it is also not designed to turn the refrigerator compartment into a freezer.
⚠️ Warning: The door seals in the refrigerator compartment may not be designed to withstand extreme temperature changes. When trying to deep freeze, the rubber may become rough and lose its seal.
If you are critically short of space in the freezer, it is better to consider purchasing a separate chest freezer or cabinet rather than putting the main unit at risk. Modern compact models take up minimal space and consume little energy.
What will happen to vegetables at a temperature of -2°C?
Water vegetables (cucumbers, tomatoes, lettuce) lose turgor at temperatures below 0°C. The cell walls are destroyed, and after defrosting they turn into mush. Potatoes may acquire a sweetish taste due to the breakdown of starch.
Alternative solutions and emergency measures
If you need to freeze food right now, and the freezer is full, you can use several life hacks that do not require rebuilding the refrigerator. The first way is to use the wind cooling effect. Place the products at the outlet of cold air (in zones Multi Air Flow), having previously wrapped them in a thin cloth to accelerate heat transfer.
The second method is to create a “cold battery”. Freeze several bottles of water in your existing freezer, then transfer them to the main compartment, placing them next to foods that require refrigeration. This will help lower the temperature locally, but not for long.
The third option is to temporarily disable the mode Super Cool (if it exists) in neighboring zones in order to transfer the compressor resource to one point. But remember that this is a temporary measure for 2-3 hours, no more.
Frequently asked questions (FAQ)
You can Is it possible to keep meat in the refrigerator for a week if you set the minimum temperature?
No, even at a temperature of 0...+1°C it is safe to store meat for no more than 3-4 days. Long-term storage is only possible with deep freezing (-18°C), which a conventional refrigerator compartment cannot provide. The risk of poisoning is too great.
Why does ice form on the back wall of the refrigerator during strong cooling?
This happens because the temperature of the evaporator drops below the dew point and freezing point of the moisture contained in the air of the chamber. In normal mode, this moisture should have time to evaporate into the drainage system, but with extreme settings the defrost cycle does not have time to work.
Are there refrigerators that can also work as freezers?
Yes, there are combined models or refrigerators with a variable freshness zone (Vario Zone), where the temperature in one of the compartments can be changed over a wide range range from -20°C to +10°C. However, these are special, more expensive models.
How to quickly defrost a refrigerator after experimenting with low temperatures?
Do not use a hairdryer or hot water to avoid damaging the plastic and seals. Simply unplug the device, open the doors and leave for 4-6 hours. Place towels to absorb melt water.