The internal structure of a household refrigerator often remains a mystery to the average user until it breaks down or requires service. The central element in the cooling system is not the compressor itself, but the substance circulating through the tubes - the refrigerant. It is this gas, changing its state of aggregation, that takes heat from the chambers and releases it into the environment, providing a low temperature for storing products.
Many people mistakenly believe that all models use the same substance, but this is not the case. Over the past decades, the industry has moved from toxic compounds to environmentally friendly but flammable compounds. Understanding what is in your unit is critically important during repairs, since different refrigerants require different oils and maintenance technologies. which gas exactly charged in your unit, is critically important during repairs, since different refrigerants require different oils and maintenance technologies.
In this article we will take a detailed look at the evolution of refrigerants, their chemical properties, impact on the ozone layer and climate, and also answer the main questions about safety modern isobutane systems. You will learn why old freons are prohibited and how they differ from those used in new models Liebherr or Bosch.
What is freon and why it is called differently
The term “freon” has become a common noun to refer to any refrigerants, although technically this is a trademark of the company Chemours (previously DuPont). In the professional environment and in documentation, designations according to the ASHRAE standard are more often found, for example R-12 or R-134a. These codes indicate the chemical formula of the substance, its flammability and toxicity.
Refrigerants are divided into several classes depending on their chemical composition. The first generations were chlorofluorocarbons (CFCs), followed by hydrochlorofluorocarbons (HCFCs), and finally hydrofluorocarbons (HFCs) and hydrocarbons (HCs). Each class has its own physical and chemical characteristicswhich determine the pressure in the system and the type of compressor oil used.
⚠️ Attention: Never try to determine the type of gas by smell or color. All refrigerants are colorless and most are odorless in their pure form. Incorrect identification during refilling will lead to compressor failure.
Modern standards require manufacturers to indicate the type of refrigerant on a special sticker located on the back wall or inside the chamber. Ignoring this information during repairs is unacceptable, since mixing different types of gases can cause a chemical reaction or explosion.
Evolution of refrigerants: from R12 to modern analogues
The history of refrigeration technology knows several key stages in the change of working fluids. For a long time, the standard was R-12 (difluorodichloromethane). It was an ideal agent: non-flammable, non-toxic, with excellent refrigeration properties. However, in the 1970s, scientists discovered that chlorine vapor released from this gas in the upper atmosphere was destroying the Earth's ozone layer.
As a result of the Montreal Protocol, the production of R-12 was almost completely stopped. It was replaced by R-134a (tetrafluoroethane). This gas no longer contained chlorine and was safe for the ozone layer, but had a high global warming potential. However, it became a mass standard for household appliances in the late 90s and 2000s.
Today there is a trend towards the use of natural refrigerants such as isobutane. This is a return to the roots, but at a new technological level. Modern systems with R-600a are quieter, consume less electricity and require less substance for effective cooling.
It is important to understand that the transition to new gases required a change in the design of the entire system. Compressors have become hermetically sealed, the diameter of the tubes has changed, and the requirements for evacuation of the circuit have increased manifold. If in the era of R-12 the system could simply be purged with nitrogen, then for R-134a and R-600a a deep vacuum is required.
Comparison table for the main types of refrigerants
To systematize information about what gas is used in refrigerators, it is convenient to use a comparison table. It shows the key differences between the main types of agents used in different decades.
| Refrigerant type | Chemical formula | Safety | Ecological impact |
|---|---|---|---|
| R-12 (Freon) | CCl2F2 | Non-toxic, non-flammable | Depletes the ozone layer |
| R-134a | CH2FCF3 | Non-toxic, non-flammable | High warming potential |
| R-600a (Isobutane) | C4H10 | Explosive when mixed with air | Environmentally neutral |
| R-290 (Propane) | C3H8 | High fire hazard | Environmentally neutral |
The table shows that safety for humans often comes into conflict with safety for the planet. R-12 was safe in everyday life, but destructive for nature. R-600a is ideal for the environment, but requires strict adherence to fire safety measures during production and repair.
Modern manufacturers, such as Electrolux or Haier, are actively introducing R-600a, since this gas allows the creation of more energy-efficient models of class A++ i above. A smaller amount of substance in the circuit also reduces the load on the compressor.
Detailed analysis of R-134a: the standard of the last decade
Refrigerant R-134a has become the golden mean in the history of refrigeration. It replaced R-12 and was used in the vast majority of refrigerators manufactured from the mid-90s to the mid-2010s. Its main advantage is inertia. It does not burn, does not explode and is not toxic when inhaled in small concentrations.
However, R-134a has its own characteristics that the master should know. This gas operates at higher pressures than R-12 and requires the use of synthetic polyester oil (POE). Unlike mineral oils, synthetics are very hygroscopic, that is, they actively absorb moisture from the air.
Moisture entering a system with R-134a and synthetic oil leads to the formation of acids that corrode the compressor windings and cause blockage of the capillary tube. Therefore, when repairing such systems, the open circuit time should be minimal.
Why is R-134a gradually disappearing from the market?
Although R-134a does not destroy the ozone layer, it is a potent greenhouse gas. Its global warming potential (GWP) is thousands of times higher than CO2. New environmental regulations (for example, F-gas regulation in the EU) limit its use, forcing manufacturers to switch to R-600a.
Diagnostics of R-134a leaks also has its own nuances. Since this gas is odorless, electronic leak detectors that react to halogens or a nitrogen and soap solution pressure test technique are used to search for damage.
Isobutane R-600a: a modern and environmentally friendly choice
Today, the answer to the question “what gas is used in refrigerators” is most often heard - isobutane (R-600a). It is a hydrocarbon that is a by-product of petroleum refining. It has excellent refrigeration properties and allows you to reduce the energy consumption of the device by 10-15% compared to R-134a.
The main feature of isobutane is its flammability. In concentration with air it forms an explosive mixture. That is why you can see a warning sign in the form of a flame on the back wall of modern refrigerators. However, you should not be afraid of this: the amount of gas in the circuit of a household refrigerator is negligible (usually 30-60 grams), which is not enough for a serious explosion in an ordinary kitchen.
Manufacturers are implementing many protective measures:
- ⚡ Use of intrinsically safe compressors with a sealed start relay.
- 🛡️ Use of special valves that prevent gas from escaping when tubes rupture.
- 🚫 Refusal of electrical components inside the chambers (light bulbs are replaced with LEDs with a remote driver).
Working with R-600a requires highly qualified specialists. It is forbidden to turn on the compressor when the circuit is open, and soldering of pipelines can only be done after thoroughly purging the system with nitrogen or using special solders with a low melting point.
⚠️ Attention: If you smell gas in the kitchen and you have a modern refrigerator, do not turn on the lights or use open fire. Ventilate the room and call a professional. Self-repair of systems with R-600a is strictly prohibited without special equipment.
Leakage problems and fault diagnosis
Refrigerant leak is one of the most common reasons for calling for service. Symptoms of this process are insufficient cooling, operation of the compressor without stopping, or, conversely, its complete failure (if the thermal relay has tripped). In older models with R-12, leaks often occurred through the condenser (the “warm wall” at the back), which rusted over time.
In modern models with a foamed evaporator, the situation is more complicated. If the gas has escaped and there is no visual damage, most likely corrosion has eaten the tube inside the polyurethane foam layer. Repair in this case is often unprofitable, as it requires opening the housing and installing an external “crying” evaporator.
To find leaks, technicians use:
- 🔍 Electronic leak detectors (sensitive to freon vapors).
- 🎈 Pressure testing with nitrogen under pressure (usually 10-15 atm) with pressure gauge control.
- 🧼 Soap solution (for rough localization of fistulas).
It is important to note that you cannot simply “add gas”. The refrigerator system is sealed, and if the gas escapes, then there is a hole. Until it is eliminated, a new portion of the refrigerant will also evaporate. In addition, oil leaves the system along with the gas, and its lack will lead to a wedge of the compressor.
☑️ Signs of a freon leak
FAQ: Frequently asked questions about refrigerants
Can gas from a refrigerator cause poisoning?
Modern gases (R-134a, R-600a) with a single short-term inhalation in household quantities do not cause severe poisoning. However, R-600a displaces oxygen, which can cause asphyxiation in confined spaces. R-12 and R-22, when in contact with an open flame, can form phosgene, a chemical warfare agent, so you cannot solder pipes without venting the gas.
Why is there less gas in new refrigerators?
This is due to the increased efficiency of heat exchangers and compressors. Isobutane (R-600a) has a greater refrigerating capacity per unit mass than old freons, so to cool the same volume of chambers, significantly less of it is required (sometimes 3-4 times).
Do you need to regularly refill the refrigerator with gas?
No. A refrigerator is a sealed system designed for its entire service life (10-15 years or more). If the gas escapes, it means that a depressurization has occurred (corrosion, mechanical damage) that must be eliminated. There is no scheduled refilling.
Is freon harmful to the ozone layer?
Old freons (R-12, R-22) containing chlorine actually destroyed the ozone layer. Modern refrigerants (R-134a, R-600a, R-404a) do not contain chlorine and are safe for the ozone layer, although some of them can affect the greenhouse effect.