In the old times of the formation of air conditioners as an original class of devices, it was customary to use toxic and harmful ammonia as a refrigerant. This gaseous substance posed a great danger to the human body. Ammonia was replaced by the so-called freons. For the first time, a chemical substance, later called Freon, was synthesized in 1928 by a chemist from General Motors Corporation.

Technically, calling refrigerants freons is not entirely correct. The term stuck thanks to the American company DuPont, which registered the trademark "FREON". For many years, this name has been used as a general technical term for refrigerants. The designation of refrigerants was introduced in the early 1930s by the Kinetic Chemical Company. It was one of the first to establish the industrial production of refrigerants. Refrigerants were marked with the letter R (from the Refrigerant). These principles are still used today.

One of the most "old" brands of refrigerant used in air conditioners is R22. Let's start the "debriefing" with it. We will not dive deep into technical details, but will analyze the key features of all popular types of refrigerants for air conditioning systems.

R22

R22 refrigerant is a non-flammable inert gas from the group of chlorofluorocarbons. The substance is colourless and has a slight odor of chloroform. For many years, R22 has been very popular in air conditioning systems. It is inexpensive, characterized by high cooling properties and uniform composition (isotropy). When the substance is used, its components disappear gradually and evenly – after the discovery of the fact of leaks in the refrigerant circulation circuit, there are no problems in refueling the air conditioner with freon. Another positive feature of the R22 refrigerant is its low operating pressure, due to which freon has almost no effect on the elements of the refrigerant circuit. Mineral oils are used in air conditioner compressors operating on R22 refrigerant.

Different types of refrigerant are supplied in cylinders of different colors. R22 is produced in green cylinders.

According to the “harmfulness” scale, the R22 refrigerant belongs to substances of the 4th hazard class. Excessive concentration of this gas promises dizziness, drowsiness, overexcitation, exhaustion of the body and even loss of consciousness. And at extremely high temperatures above 250 °C, R22 freon decomposes into toxic products. The main blow falls on the ozone layer of the planet – the refrigerant has a detrimental effect on it.

The first step to abandon the R22 refrigerant in favor of more gentle types of freon was the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer (in 1987). Since about 2010, the use of this refrigerant in air conditioners has been banned in the United States and European Union countries. New models of air conditioning equipment based on R22 freon are not produced, but old ones can still be found in stores. For their "refueling", the production of small volumes of R22 refrigerant continues.

Pros of R22 refrigerant :

  • affordable cost;
  • low working pressure;
  • isotropic properties (homogeneity of composition);
  • good cooling capacity.

Cons of R22 refrigerant :

  • health hazard in high concentrations;
  • detrimental effect on the ozone layer;
  • decomposes into toxic gases at high temperatures.
Air conditioners with R22 refrigerant

R407C

To replace the environmentally unsafe R22 , the R407C refrigerant was invented, which has a minimal detrimental effect on the ozone layer. This is a zeotropic mixture of freons R125, R32 and R134a in proportions of 25%, 23% and 52%, respectively. In terms of cooling capacity and saturated vapor pressure, the composition of R407C is very close to the characteristics of R22. As a result, it can be used in equipment designed for R22 without significant changes to the cooling systems. You only need to replace the mineral oil with polyester to lubricate the internal components of the compressor.

R407C refrigerant is a zeotropic mixture. Due to the heterogeneity of the composition, it almost went out of wide use.

The term "zeotropic mixture" in the properties of the R407C refrigerant hides the heterogeneity of the composition. With leaks in the circuit, the evaporation of a substance occurs unevenly, since its components have different boiling points and different volatilization rates. Even with minimal violations of the integrity of the cooling circuit, R407C freon changes its properties – the situation can be corrected only by a complete refilling of the air conditioner. And such maintenance is not cheap.

The R407C refrigerant has found its application mainly in semi-industrial and industrial air conditioning systems.

Pros of R407C refrigerant :

  • high power consumption efficiency;
  • reduced level of toxicity;
  • environmental safety;
  • the possibility of using as a replacement for the R22 refrigerant without significant modifications to the cooling systems.

Cons of R407C refrigerant :

  • zeotropic properties (heterogeneous composition);
  • the need to completely replace the refrigerant in the circuit in case of leaks and, as a result, the high cost of such maintenance.

R410A

Unlike R407C, refrigerants labeled R410A are azeotropic – although they consist of a mixture of two gases, however, their components have the same properties in terms of boiling point and volatilization of substances during evaporation. R410A freons are a mixture of difluoromethane R32 and pentafluoroethane R125 gases in a 50/50 ratio. In the event of a leak in the refrigeration circuit, the composition of the refrigerant does not change, so that the system can be topped up instead of completely refilled.

The vast majority of modern air conditioners operate on R410A refrigerant, but they have already begun to actively switch to R32 freon.

The R410A refrigerant does not contain chlorine, has no toxic effect on human health, and has minimal ozone depletion potential. The use of this freon allows you to achieve greater cooling capacity with a minimum of power consumption. Many split systems on R410A refrigerant support heating operation at outdoor air temperatures down to about -15 °C.

The reverse side of the R410A freon coin is the need to withstand high pressure in the refrigerant circulation system. This point puts forward serious requirements for the strength and reliability of the cooling circuit, and also complicates the procedure for pumping refrigerant into the air conditioner, which affects the final cost of the maintenance.

Pros of R410A refrigerant :

  • excellent cooling capacity with minimal power consumption;
  • reduced level of toxicity;
  • the possibility of refueling the cooling circuit in case of depressurization.

Cons of R410A refrigerant :

  • high operating pressure makes serious demands on the strength and reliability of the cooling circuit;
  • the complexity of refueling and the high cost of maintenance.

Today R410A freon is the most popular type of refrigerant used in air conditioning systems. But it was not destined to remain so for long. By 2030, this refrigerant should be withdrawn from circulation at least in European countries – EU regulations require a significant reduction in the use of fluorinated greenhouse gases, and therefore it became necessary to switch to safer refrigerants. In particular, R32.

Air conditioners with R410A refrigerant

R32

Previously , the R32 refrigerant has already been used in air conditioning equipment as a component of R407C and R410A freons. However, it was decided to bring it into a separate type of refrigerant. Many factors contributed to it: difluoromethane R32 has almost no effect on the ozone layer of the planet, freon of this brand is low-toxic, hardly flammable and energy efficient. In addition, the density index of R32 is a good third lower than that of R410A – with equal cooling capacity, this makes it possible to use less refrigerant in air conditioning systems.

Freon R32 is the most friendly to the environment and the ozone layer of the planet.

Air conditioning equipment, in the circuit of which R32 refrigerant circulates, works more efficiently and consumes less energy. Air conditioners of the highest ranks of energy efficiency work on R32 freon. Also, difluoromethane is a one-component substance, and therefore it is very convenient to use due to the possibility of additional refueling of the circuit without the need to completely remove the refrigerant from the system.

The main disadvantage of models with this type of refrigerant is a high price. Moreover, it is connected not so much with the cost of the R32 itself, but with the specific requirements for the design of the refrigeration circuit. Nevertheless, R32 freon is rightfully considered the safest among all refrigerants that exist today. It is the best choice for new generation air conditioners, including models with inverter control.

Pros of R32 refrigerant :

  • excellent cooling capacity;
  • low toxicity and flame hardly flammable properties;
  • the best level of environmental safety;
  • the possibility of refueling the cooling circuit in case of depressurization;
  • the low density of R32 allows the use of less refrigerant in the cooling circuit;
  • high rates of efficiency and energy saving.

Cons of refrigerant R32 :

  • serious requirements for the strength and reliability of the cooling circuit;
  • the high cost of the refrigerant and the high cost of maintenance.
Air conditioners with R32 refrigerant

How to detect a refrigerant leak

Refrigerant is the main working substance in air conditioning systems. With a decrease in the concentration of freon in the refrigeration circuit, the first thing that happens is that the efficiency of the air conditioner decreases. Instead of cold air, the air conditioner starts to blow out barely cool or warm air. If the leak is not fixed in time, it promises serious damage in the future, up to the failure of the compressor due to overheating. Moisture can also get into a depressurized system – its interaction with the refrigerant leads to the formation of acid, which causes damage to the windings of the discharge element.

Diagnosis and refueling of the air conditioner with refrigerant must be trusted to specialists.

To check the system for refrigerant leaks, the following methods are usually used:

1. Visual inspection by characteristic oil stains on valves or tubes.
2. Application of a soap solution in places of alleged leaks (with free access to them).
3. Checking the error code on the display of the indoor unit of the air conditioner (if any).

If it was not possible to identify the problem, you should use the help of maintenance specialists. They will check the system for tightness under high pressure, if necessary add ultraviolet dyes to the circuit, remove small elements from the air conditioner for visual inspection for leaks under water (some elements in the air conditioning system can be removed without violating the tightness of the circuit, but it is not recommended to do it yourself ). Another option for searching for leaks involves the use of a specialized tool such as an electronic or ultrasonic leak detector.

Visual inspection for leaks is carried out at pipe joints and near valves. Soap solution will help to identify the depressurization of the circuit.

How often do you need to refill the air conditioner with freon

To avoid refrigerant leaks and breakdowns of the working units of the air conditioner, it is necessary to call specialists every two to three years for a preventive inspection of equipment and refueling it with freon. Also, regular monitoring of the operation of the device will help prevent the occurrence of problems. This must be done every time the equipment is turned on, monitoring the correspondence of the mode with the real temperature. And from time to time it wil be useful to perform a visual inspection of the junctions of the tubes with the units.


Long and trouble-free operation for your air conditioner!