When a household refrigerator stops freezing or makes strange sounds, many owners immediately remember the need to top up the “liquid”. However, in technical usage and among repairmen you will not find such a term. The correct name of the working substance is refrigerant, and in everyday life it is most often called freon. This substance is the heart of the refrigeration machine, it is thanks to its circulation and change in the state of aggregation that heat is removed from the chambers.
Many people mistakenly believe that freon is a single substance, but in fact it is a whole group of chemical compounds. Different models and years of production of equipment may use completely different gases, which are not always compatible with each other. Understanding what what type of refrigerant is used in your unit is critical when diagnosing leaks or planning repairs.
In this article we will take a closer look at the chemical composition of different types of refrigerants, their physical properties and their impact on the environment. You will learn why some gases are prohibited for use, while others are considered the modern standard. We will also touch upon safety issues, since improper handling of some species working fluid can be dangerous to human health.
Scientific name and principle of operation
The technically correct name for the liquid circulating in the refrigerator circuit is refrigerant or refrigerator. In chemical nomenclature, these substances belong to the class of fluorine- and chlorine-containing hydrocarbon derivatives. Their main task is to effectively absorb heat during evaporation and release it during condensation, working in a closed cycle.
The cooling process is based on the physical property of these substances to boil at very low temperatures even at normal atmospheric pressure. The compressor compresses the gas, turning it into a high-temperature liquid, which then releases heat through the condenser (the grill at the back of the refrigerator). Passing through the capillary tube and evaporator, the pressure drops sharply and the refrigerant boils, taking heat from the products. freon, turning it into a high-temperature liquid, which then releases heat through the condenser (the grill at the back of the refrigerator). Passing through the capillary tube and the evaporator, the pressure drops sharply and the refrigerant boils, taking heat from the products.
Why is freon not consumed?
In a working refrigerator, freon circulates in a closed circuit and is not consumed like gasoline in a car or tap water. If you are told that you need to “top up freon” every six months, this means that there is a leak in the system that needs to be fixed before refueling.
It is worth noting that modern environmental standards dictate their own rules. Old types of refrigerants containing chlorine destroy the ozone layer, so they are gradually being abandoned in favor of safer analogues. That is why during repairs it is important to know the exact markings so as not to violate environmental standards and the efficiency of the equipment.
⚠️ Attention: Never try to open the copper circuit yourself or disconnect the tubes if there is pressure left in the system. A sudden release of gas under pressure can lead to eye injuries or frostbite of the skin.
Main types of refrigerants: R12, R134a, R600a
The history of the development of refrigeration technology goes back more than a century, and during this time the formulas of refrigerants have changed several times. The most common in Soviet times and in the early 90s was R12 (difluorodichloromethane). This substance had excellent refrigeration properties, but turned out to be extremely destructive for the ozone layer of the planet, which led to its complete ban by the Montreal Protocol.
R12 was replaced by R134a (tetrafluoroethane). This gas no longer contains chlorine, so it is considered safe for the ozone layer, although it has a high global warming potential. It is still widely used in many mid-range refrigerator models. R134a operates at higher pressure than its predecessor, which requires the use of more powerful compressors.
The most modern and environmentally friendly solution today is R600a (isobutane). It is a hydrocarbon gas that does not destroy ozone and has minimal impact on the climate. However, it has one significant drawback - high flammability. That is why refrigerators based on R600a require special care during repairs and a special explosion-proof design of electrical components.
- 🧊 R12 - obsolete freon, prohibited for production, is found only in very old equipment.
- 🌍 R134a - safe for ozone, but effective only under moderate loads, requires synthetic oil.
- 🔥 R600a —the most energy efficient and environmentally friendly, but explosive when the concentration in air is more than 3%.
Physical properties and safety
Despite the fact that all refrigerants perform the same function, their physical properties can differ radically. Most of them are colorless and odorless, making the leak invisible and inaudible to a person without special equipment. Some types, such as ammonia (R717)used in industrial installations, have a pungent odor, but in household refrigerators only inert gases are used.
The issue of toxicity is often controversial. Modern household freons (R134a, R600a) are low-toxic during short-term inhalation of small concentrations. However, in a confined space, a large leak can displace oxygen, causing asphyxiation. In addition, upon contact with an open flame, some refrigerants can decompose to form phosgene a chemical warfare agent.
Particular attention should be paid to the boiling point. When leaving the system, liquid freon instantly evaporates, causing sudden local cooling. Contact with a jet of liquid refrigerant on the skin causes a serious thermal burn, similar to frostbite. Therefore, any work on filling the circuit should be carried out wearing protective gloves and goggles.
Comparison table of refrigerant characteristics
To better understand the differences between types of working substances, it is worth considering their technical parameters in comparison. These characteristics help technicians select the right equipment for refueling and diagnose problems in the system.
| Parameter | R12 (Outdated) | R134a (Modern) | R600a (Eco-standard) |
|---|---|---|---|
| Chemical formula | CF2Cl2 | CH2FCF3 | C4H10 |
| Boiling point (°C) | -29.8 | -26.3 | -11.7 |
| Effect on ozone | High (destroys) | Zero | Zero |
| Flammability | Does not burn | Does not burn | Flammable |
| Oil type | Mineral | Synthetic (POE) | Mineral |
As can be seen from the table, the transition to new types of refrigerants required a change in the design of the refrigerators themselves. For example, R134a is incompatible with the mineral oils used in older compressors, so when converting the system, the oil and filter drier would have to be completely changed.
The choice of refrigerant type also affects energy consumption. R600a allows you to create quieter and more economical refrigerators, since it has better heat capacity. That is why most modern models of class “A++” and higher operate on isobutane.
Diagnostics of leaks and signs of freon shortage
Since freon is not consumed during operation, its shortage always indicates a violation of the tightness of the system. It is almost impossible to detect a leak visually, since the gas is transparent. However, there are indirect signs that should alert the owner of the equipment.
First of all, pay attention to the operation of the compressor. If it works almost non-stop, and the temperature in the chambers does not drop to the required values, this is a sure sign of loss of refrigerant. There may also be insufficient cooling or a complete absence of cold when the motor is running.
- 👂 The compressor hums continuously or turns on too often.
- ❄️ The freezer compartment freezes poorly, and in the main chamber the temperature is above +10°C.
- 💧 The appearance of ice in only one corner of the evaporator or its complete absence.
- 🔥 Excessive heating of the side walls of the refrigerator or condenser at the back.
☑️ Signs of a freon leak
Sometimes craftsmen use a soap solution to find a leak, applying it to the joints of the tubes. The appearance of bubbles will indicate the release of gas. However, in sealed factory systems, where the tubes are mounted in the housing, this method is ineffective, and the use of electronic leak detectors or ultraviolet additives in the oil is required.
⚠️ Attention: If you find mechanical damage to the tubes (for example, you pierced the evaporator with a knife during defrosting), do not turn on the refrigerator. The entry of moisture and air into the system through the hole will lead to rapid failure of the compressor.
Is it possible to refuel the refrigerator yourself?
The question of refueling the refrigerator yourself often arises among home craftsmen, but the answer is clear: without special equipment and a license, this is impossible and dangerous. The charging process requires not only a gas cylinder, but also a vacuum pump, a pressure gauge station and dosage scales.
Before charging new refrigerant, the system must be thoroughly evacuated. This is to remove air and, more importantly, moisture. Moisture in the system is the main enemy of the refrigerator: it freezes in the capillary tube, forming an ice plug, and reacts with the oil, forming acid, which destroys the compressor windings from the inside.
Procedure for a professional:1. Finding and eliminating leaks (soldering).
2. Pressure testing with nitrogen to check tightness.
3. Evacuation of the system (up to -1 atm).
4. Refueling is strictly based on weight (grams!).
5. Checking operation and tightness.
In addition, the amount of refrigerant in a household refrigerator is measured in grams (usually from 30 to 150 grams). Refilling even 10-20 grams above normal will lead to a sharp increase in pressure, triggering emergency protection and possible rupture of the circuit. Underfilling will also not give the desired cooling effect.
Environmental aspects and disposal
Modern legislation strictly regulates the handling of refrigerants. The release of freon into the atmosphere is considered an environmental violation in many countries. This is especially true for old freons, but new types, although safe for ozone, are greenhouse gases.
When disposing of an old refrigerator, it is necessary to hand it over to specialized collection points. There, technicians carefully sift out the remaining refrigerant and oil, after which they are sent for recycling or destruction. Throwing equipment into a regular landfill is strictly prohibited, since if the housing is damaged, gas will escape into the atmosphere.
Manufacturers are constantly working to reduce the amount of refrigerant used in new models. Modern designs make it possible to reduce the filling mass to a minimum while maintaining high efficiency. This not only reduces the environmental footprint, but also reduces the risk of serious consequences in the event of depressurization.
Is freon from an old refrigerator dangerous for people?
Freon itself (R12, R134a) in small quantities is not toxic to humans. However, when heated, it can release harmful substances. The main danger is that the heavy gas can displace oxygen at low points in the room, causing asphyxiation. In addition, old freons form phosgene when in contact with fire.
Why can’t you mix different types of freon?
Mixing different refrigerants (for example, R12 and R134a) leads to unpredictable chemical reactions, the formation of acids and sediment. This is guaranteed to damage the compressor and clog the capillary tube. Each type of gas requires its own type of oil and filter-drier.
How can I find out what kind of freon is in my refrigerator?
Information about the type of refrigerant and its quantity (in grams) is always indicated on a special sticker (nameplate). It is usually located inside the refrigerator compartment on the side wall, on the back wall, or on the plinth at the bottom of the refrigerator. Look for the inscription “Refrigerant” or “Coolant.”
Can a refrigerator operate without freon?
No, operation without refrigerant is impossible. The compressor will drive the void, trying to create pressure, but no heat exchange will occur. Long-term operation without refrigerant (especially if there is a leak) can lead to overheating and combustion of the compressor windings, since freon and oil are also involved in cooling the motor.
How much does it cost to refill a refrigerator with freon?
The cost depends on the type of refrigerant, the amount of work and the region. It is important to understand that you pay not so much for gas (its cost is relatively low), but for the work of a specialist in finding leaks, soldering, vacuuming and precise filling. Cheap “refueling” without repair is a waste of money.