Many owners of household appliances do not even think about what makes their refrigerator cool food while the device is properly performing its function. However, when ice stops forming in the freezer and it becomes warm in the refrigerator compartment, the first thing people think about is “freon.” This is what they call it in everyday life - a working substance that circulates through a system of tubes, taking heat from the internal volume of the chamber and releasing it into the environment. Understanding what a refrigerant is will help you quickly diagnose a breakdown and avoid dangerous situations when operating equipment. refrigerant - a working substance that circulates through a system of tubes, taking heat from the internal volume of the chamber and releasing it to the environment. Understanding what refrigerant is will help you quickly diagnose a breakdown and avoid dangerous situations when operating equipment.
The physical principle of operation of this substance is based on the property of easily changing from a liquid to a gaseous state and back when the pressure changes. This process, called phase transition, is accompanied by the absorption or release of a huge amount of energy. Without this mechanism, the modern refrigerator would simply be a sealed box, unable to maintain a low temperature. In this article we will analyze in detail what types of gases are used today, how they differ from those that were used decades ago, and what to do if the system has lost its tightness.
Operation principle and the role of the working substance
The main task of the refrigerant is to transfer thermal energy. The cycle begins with a compressor, which compresses the gaseous substance, sharply increasing its pressure and temperature. In this heated state, the gas enters the condenser - the same black lattice coil on the back wall that can often be seen on older models. Here the substance cools down and enters the liquid phase, giving off heat to the air in the room.
Next, the liquid passes through capillary tube or the throttle valve, where the pressure drops sharply. Once in the evaporator (inside the freezer), the liquid refrigerant boils at a very low temperature, intensively absorbing heat from the food. It is this process that provides the familiar cold. After the evaporator, the gas returns to the compressor again, and the cycle repeats endlessly as long as the refrigerator is plugged in.
- 🧊 Evaporation: heat absorption inside the chambers when changing into gas.
- 🔥 Compression: increase in pressure and temperature compressor.
- 💨 Condensation: heat transfer to the outside when it passes into liquid.
It is important to understand that the efficiency of the entire system directly depends on the quantity and quality of the filled gas. If an “air lock” forms in the circuit or a leak occurs, the thermodynamic cycle is disrupted. The compressor begins to wear out, trying to compensate for the lack of pressure, but the temperature does not drop to the desired values. In modern models, this process is monitored by electronics, which can block the motor from starting in case of critical errors.
The evolution of refrigerants: from ammonia to isobutane
The history of the development of refrigerants is a constant search for a balance between efficiency, safety and environmental friendliness. In the first industrial and domestic installations it was often used ammonia (R717). This substance had excellent refrigerating properties, but was toxic and explosive if leaked. For a long time, engineers have been looking for an alternative that would be safe for humans in domestic conditions.
In the middle of the 20th century, the revolution began chlorofluorocarbons (CFC), known under the trademark Freon-12 (R12). They were inert, did not burn and had no odor. However, it later became clear that when these compounds enter the atmosphere, they destroy the Earth’s ozone layer. This led to the Montreal Protocol and the gradual ban of ozone-depleting substances. They were replaced by hydrochlorofluorocarbons (HCFC), which are also now being phased out.
⚠️ Attention: Never try to replace the refrigerant in an old refrigerator with a modern one yourself analogue without completely flushing the system and changing the oil. Different types of oils and gases can enter into a chemical reaction, which will lead to blockage of the capillary system and failure of the compressor.
Today, two main types of substances dominate in household refrigerators. The first is R134awhich does not destroy the ozone layer, but has a high global warming potential. The second, and most common in modern models, is isobutane (R600a). This is a hydrocarbon gas that is absolutely environmentally friendly, but is flammable. That is why in the instructions for new refrigerators you can find warnings about prohibiting the use of open fire near the circuit.
Why is R600a better for the environment?
Isobutane (R600a) has zero ozone depletion potential and negligible potential global warming compared to fluorine-containing analogues. It naturally decomposes in the atmosphere without accumulating or forming harmful compounds.
Comparative table of the main types of refrigerants
To better understand the differences, let's consider the main characteristics of substances that can be found in various technologies. Understanding these differences is important not only for environmentalists, but also for repairmen, since each type requires specific equipment for charging and diagnostics.
| Refrigerant type | Designation | Safety | Application |
|---|---|---|---|
| Freon-12 | R12 | Safe, but harmful to ozone | Old refrigerators (before the 90s) |
| Tetrafluoroethane | R134a | Does not burn, is not toxic | Medium and large refrigerators |
| Isobutane | R600a | Explosive when mixed with air | Modern compact models |
| Ammonia | R717 | Toxic, pungent odor | Industrial installations |
As can be seen from the table, modern household models most often use R600a or R134a. Manufacturers choose isobutane due to its high energy efficiency and low noise level during compressor operation. However, the presence of hydrocarbon gas imposes special requirements on the tightness of connections during production and repair.
It is worth noting that mixing different types of refrigerants is strictly prohibited. Even a small admixture of R12 in a system designed for R134a can change the boiling and condensation pressure, which will lead to incorrect operation of the thermostat and overload of the motor. The amount of refrigerant in a domestic refrigerator is usually from 30 to 150 gramswhich is a very small volume compared to industrial chillers.
Signs of leakage and fault diagnosis
The refrigeration circuit is a closed system, and in good condition, the gas does not go anywhere for years. If you notice that the refrigerator has stopped freezing, the compressor runs continuously or turns on rarely, and it is warm inside, most likely depressurization has occurred. A leak can be caused by corrosion of tubes, mechanical damage during transportation, or a manufacturing defect in a weld.
It is almost impossible to determine a leak visually, since most modern gases are colorless and odorless. However, there are indirect signs that should alert the owner. First of all, pay attention to the operation of the engine: if it hums constantly, without turning off, but there is no cold, this is a sure sign. There may also be swelling of the side walls of the housing in the places where the evaporator is laid.
- 🌡️ Temperature: products in the refrigerator compartment begin to deteriorate faster than usual.
- ❄️ Ice: ice melts in the freezer, water or an uneven “snow coat” appears shapes.
- 🔊 Sound: the appearance of gurgling or hissing sounds that were not there before.
⚠️ Attention: If you hear hissing or smell a specific chemical odor (typical for older models with R12), immediately ventilate the room. Although modern gases are less toxic, the concentration of vapors in a small room can cause suffocation or headaches.
For accurate diagnostics, technicians use leak detectors - devices that respond to the concentration of halogens or hydrocarbons in the air. The nitrogen pressure test method is also used: the system is filled with inert gas under pressure and the pressure gauge is monitored. If the arrow falls, it means the seal is broken. Finding a leak on your own without equipment is extremely difficult, especially if it is a microphone leak.
Danger to humans and safety rules
The issue of refrigerant safety often causes a lot of controversy. Old freons (R12) upon contact with an open flame could form phosgene, a chemical warfare agent. Modern analogues (R134a, R600a) are safer in this regard, but have their own risks. Isobutane, used in most new refrigerators, is a flammable gas. In a confined space, at a concentration of 13% to 30%, it forms an explosive mixture with air.
However, the amount of gas in a household refrigerator is so small (usually less than 100 grams) that to create an explosive concentration in a standard 10-square-meter kitchen, the leak would have to be complete and instantaneous, which is technically unlikely. However, operating rules require caution. It is prohibited to store the refrigerator in rooms with potential sources of sparks if the instructions indicate the use of flammable refrigerant.
If liquid refrigerant gets on your skin, this may cause data-i="123">, since the boiling point of these substances is very low (up to -30°C and below). Upon contact with the skin, the liquid instantly boils, taking heat away from the tissues. Therefore, any work on servicing the system must be carried out wearing protective gloves and goggles. frostbite, since the boiling point of these substances is very low (up to -30°C and below). Upon contact with the skin, the liquid instantly boils, taking heat away from the tissues. Therefore, any work on servicing the system must be carried out wearing protective gloves and goggles.
☑️ Actions in case of a severe gas leak
The process of refueling and restoring the system
Restoring the refrigerator after a leak is a complex technological process that is impossible can be done at home without special tools. The procedure begins with finding and eliminating the leak. If you just add gas, it will go away again in a couple of days or weeks. After sealing the hole, the system is vacuumized.
Vacuuming is necessary to remove moisture and air. Moisture in the system is the main enemy, since at low temperatures it freezes in the capillary tube, forming an ice plug that blocks circulation. In addition, water reacts with oil and refrigerant, forming acid, which corrodes the compressor windings from the inside.
The dosage of refrigerant is carried out strictly by weight, accurate to the nearest gram, according to the data on the nameplate (technical sticker) of the refrigerator. Overfilling or underfilling will lead to incorrect operation. Different gauge stations and oils are used for different types of gases. For example, R134a requires synthetic polyester oil (POE), which actively absorbs moisture, so working with it requires special speed and accuracy.
After refueling, a test run is carried out. The technician checks the suction and discharge pressure, the temperature of the evaporator and condenser, as well as the current consumption of the compressor. Only after making sure that all parameters are normal, the service fitting is sealed and the refrigerator is handed over to the owner. The whole process can take from 1 to 3 hours, depending on the complexity of access to the evaporator.
Is it possible to refill the refrigerator yourself?
Theoretically, it is possible if you have access to professional equipment: a vacuum pump, a pressure gauge station, scales and a cylinder with the required type of freon. However, the cost of such a set of tools exceeds the price of calling a specialist. In addition, without experience, it is easy to make a mistake leading to combustion of the compressor.
How long does the refrigerant last in a refrigerator?
With a working system and no mechanical damage, the refrigerant lasts as long as the refrigerator itself - 10-15 years or more. It is not consumed during operation, but only circulates in a closed circuit. The need for refueling arises only when there is a leak.
What is the danger of freon from an old refrigerator?
Older generations of freons (R12) can release toxic substances when heated. They are also heavier than air and can displace oxygen in low areas of the room, causing suffocation. When disposing of old equipment, the gas must be pumped out by specialists.
Why is there less gas in new refrigerators?
Modern refrigerants, such as isobutane (R600a), have a higher specific cooling capacity. To achieve the same cooling effect, they require significantly less mass than old freons. This also reduces the environmental footprint during production and disposal.
What to do if the refrigerator stops freezing?
Do not panic. Check if the light inside is on and if the compressor is running. If the engine hums, but there is no cold, there is probably a leak. If the motor is silent, the problem may be in the electrics or thermostat. In any case, a specialist is needed to diagnose the cooling system.