Many owners of household appliances wondering what exactly the liquid in the refrigerator that provides the cold is called. In everyday life, this substance is often referred to simply as “coolant,” but the technically correct name is refrigerant or freon. It is the circulation of this substance in a closed circuit that allows you to maintain a low temperature in the chambers, keeping the food fresh.
It is important to understand that in a working device this liquid does not disappear anywhere and does not require replacement during its entire service life. It is not consumed like water or electricity, but constantly changes its state of aggregation, passing from gas to liquid and back. If you are faced with the fact that the refrigerator has stopped freezing, the reason may be refrigerant leak due to mechanical damage to the tubes or corrosion.
Modern models of refrigerators can use different types of gases, each of which has its own chemical properties and environmental characteristics. The energy efficiency of the device and its impact on the environment depend on the choice of a specific type. Let us examine in detail what types of substances are used today and how they differ from each other.
What is freon and how does it work
Freon is the trade name of a group of saturated aliphatic fluorinated hydrocarbons that are widely used as refrigerants. In the context of refrigeration technology, this word refers to any substance that, when compressed, turns into a liquid, and when expanded, into a gas, actively absorbing heat from the environment. This physical process underlies the operation of a compression refrigerator.
The refrigeration cycle begins in the compressor, where gaseous refrigerant is compressed under high pressure. In this state, it becomes hot and is sent to a condenser (usually a grate on the back wall), where it cools and turns into a liquid. Next, the liquid passes through a capillary tube, where the pressure drops sharply, and it boils, turning into gas and removing heat from the internal space of the chambers.
⚠️ Attention: Freon is odorless and colorless, so it is almost impossible to detect its leak by external signs without special equipment. If you smell a strange chemical smell, this may indicate an oil leak from the compressor or food spoilage, rather than the gas itself.
The key element of the system is compressorwhich acts as the heart of the refrigerator, pumping refrigerant through the system. Without its proper operation, circulation of the substance is impossible, and cold will not be generated. Modern inverter models allow you to regulate the speed of the compressor, which makes the cooling process smoother and quieter.
The main types of refrigerants in household appliances
The history of the development of refrigeration technology goes back more than a hundred years, and during this time the chemical composition of the working substances has changed several times. Early models could use ammonia or sulfur dioxide, which were effective but extremely toxic and a fire hazard. Today, the industry has switched to safer synthetic compounds.
The most common substance for many years remained R-12 (dichlorodifluoromethane). It was safe for humans, did not burn or explode. However, it was later discovered that when released into the atmosphere, it destroys the planet’s ozone layer. Because of this, the Montreal Protocol banned its production, and new formulations came to replace it.
The following types of refrigerants can most often be found in modern refrigerators:
- 🧊 R-134a — tetrafluoroethane, the most popular substitute for R-12, does not destroy the ozone layer, but has a high global warming potential.
- ❄️ R-600a (isobutane) is a natural hydrocarbon gas that is becoming the standard for European and many Asian brands due to its high energy efficiency.
- 🌍 R-407C and R-410A - mixtures of various freons, more often used in air conditioners, but sometimes found in industrial refrigeration units.
Each type of gas requires the use of a specific type compressor oil and has its own characteristics of pressure in the system. For example, R-600a works at a lower pressure, which makes it possible to make the tube walls thinner, but it is flammable, which requires special care during repairs.
Characteristics and comparison of R-134a and R-600a
Choice between the two main modern refrigerants — R-134a i R-600a — is determined by manufacturers based on the requirements for energy consumption and environmental friendliness. R-134a has long been the uncontested leader because it is inert and safe. However, it requires more powerful compressors and more substance to achieve the same cooling effect.
Isobutane (R-600a) has excellent thermodynamic properties. It requires significantly less weight (only about 30-50 grams versus 100-150 grams for R-134a), which makes refilling cheaper. In addition, it is better soluble in oil, which improves the lubrication of the rubbing parts of the compressor and reduces the noise level during operation of the unit.
For a visual comparison of the main parameters, we present a table:
| Parameter | R-134a (Tetrafluoroethane) | R-600a (Isobutane) | R-12 (Obsolete) |
|---|---|---|---|
| Chemical formula | CH2FCF3 | C4H10 | CCl2F2 |
| Toxicity | No | No (but flammable) | No |
| Impact on ozone | Safe | Safe | Destroys |
| Pressure in the system | High | Low | Average |
| Refueling consumption | ~140 grams | ~35 grams | ~150 grams |
Despite the advantages of isobutane, the transition to it requires the restructuring of production lines, since intrinsically safe assembly of electrical components is necessary. This is why you can still find R-134a in some budget or older models.
Why is isobutane flammable, but safe in the refrigerator?
Isobutane does burn, but in the refrigerator its amount is minimal (less than 60 grams). For ignition, a concentration is required that is significantly higher than what can be formed even with a complete depressurization of the system in an ordinary kitchen. In addition, the electrical contacts in such models are sealed or removed from places of possible leakage.
Signs of refrigerant leakage from the system
Since the cooling system is sealed, the liquid in the refrigerator normally does not go anywhere. However, over time, microcracks may appear in the evaporator or pipe soldering areas. It is possible to understand that gas has escaped by indirect signs, since the gas itself cannot be seen.
The first and most obvious symptom becomes increase in temperature in the refrigerator and freezer compartments. Food begins to deteriorate, the ice in the freezer melts, and a “snow coat” may appear on the walls or, conversely, complete dryness when the compressor is running. In this case, the compressor can work without stopping, trying to reach the set temperature.
Other signs of malfunction:
- 🔊 Constant hum motor - the compressor turns on and does not turn off for hours.
- 🌡️ Hot condenser — the rear grille remains cold or barely warm, although the motor is running.
- 💧 Blistering of the sides walls —in some models the evaporator is foamed into the walls, and corrosion may cause swelling of the paint.
- 🚫 No cold with the light and fan running.
⚠️ Attention: If you find oil around the compressor tubes or on the floor under the refrigerator, this is an almost guaranteed sign of depressurization. Oil comes out along with the gas, and this cannot be ignored - the compressor may burn out due to lack of lubrication.
It is difficult to find the leak on your own, as it requires the use of a leak detector or a soap solution on the removed elements. In foamed evaporators, leakage can often be determined only by indirect signs or by opening the thermal insulation.
Is it possible to refill the refrigerator yourself
The question of refilling the refrigerant yourself worries many amateur craftsmen. Theoretically, having a set of equipment (vacuum pump, pressure gauge station, scales and a cylinder with freon), it is possible to carry out the procedure. However, in practice refrigerator repair doing the refrigerant yourself is extremely difficult and often economically unfeasible.
The main problem is not in letting gas in, but in preparing the system. Before refueling, you must:
- Find and eliminate the leak (solder the tube or replace the evaporator).
- Replace the filter drier, which absorbs moisture from the air.
- Create a deep vacuum in the system to remove all air and water vapor.
- Fill the system with a strictly defined amount of refrigerant (an error of 5-10 grams is critical).
Using the wrong oil or getting moisture inside the system will lead to the formation of acids that will corrode the compressor windings from the inside. Clogging of the capillary tube is a frequent consequence of poor-quality repairs, after which the refrigerator has to be sent to a specialized service for complete bulkheads.
☑️ What is needed for professional refueling
Environmental friendliness and safety during operation
Modern requirements for household appliances dictate not only efficiency, but also safety for the planet. New generation refrigerants, such as R-600ahave zero ozone depletion potential. However, their production and disposal must be carried out according to strict rules.
When disposing of an old refrigerator, it is important not to just throw it in a landfill. Residual gas, even in small quantities, when burning garbage can release toxic compounds. Therefore, large retail chains and special equipment collection points are obliged to transfer the units to processing plants, where the freon is pumped out and neutralized.
For the user, safety lies in the correct location of the device. Do not place the refrigerator close to heating devices or cover it with a cloth that prevents heat transfer. This reduces operating efficiency and can lead to an increase in pressure in the system, which creates an emergency situation.
Is freon dangerous for humans when inhaled?
In small concentrations that can be formed during a micro-leakage in a room, modern freons (R-134a, R-600a) are not toxic. However, at high concentrations they displace oxygen, which can cause suffocation. In addition, upon contact with an open flame, some types of freons can decompose into phosgene, a chemical warfare agent. Therefore, smoking near a running refrigerator or a leak is strictly prohibited.
Why does the refrigerator hum after refilling freon?
The hum can be caused by several reasons: incorrect dosage of gas (system overload), air getting into the circuit, a malfunction of the compressor itself, or vibration of the tubes. If after professional refueling the noise increases, you need to call a technician to check the pressure and operation of the motor.
How often do you need to change the freon in the refrigerator?
Unlike the oil in a car, the freon in the refrigerator does not have an expiration date and does not require scheduled replacement. It circulates in a closed loop for decades. It needs to be changed or refilled only if a leak is detected, which is a sign of a malfunction, and not a normal operation.