What is a refrigerant?
Refrigerant is a substance through which the refrigeration cycle is carried out, in other words, the main component of such a well-known and necessary equipment as a refrigerator, air conditioner, freezer or refrigerator.
The refrigeration cycle is possible due to the fact that the refrigerant at one and the same pressure due to the change in its aggregate state can change its temperature.
Evaporating in the evaporator, the refrigerant removes the heat from the cooled volume, and then, after compression with the compressor and transition to another aggregate state, - the liquid, gives it the heat to the environment.
Therefore, the substance to be used as a refrigerant should have a number of specific properties and characteristics.
A bit of history.
For a long time, the main refrigeration agents were ammonia, carbon dioxide and sulfur dioxide, - NH3, CO2, SO2, respectively.
In 1930, dichlorodifluoromethane Cl2F2C was created, which drastically changed the situation in the field of cold production. At that time, this refrigerant, named "freon" and labeled R12, seemed perfect in its characteristics and properties.
Subsequently, on the basis of fluorochlorocarbons, a number of new freons with distinct R12 properties were obtained. Mark them decided by chemical composition: the first digit after R is the number of carbon atoms, reduced by one, the second - the number of hydrogen atoms, increased by one, and the third digit - the number of fluorine atoms.
Effect of refrigerants on the environment.
After widespread use of refrigerants in industry, research has shown a significant impact on the environment.
One of such serious impacts is the greenhouse effect that arises due to the fact that some gases of the earth's atmosphere delay the infrared radiation of the Earth. Just coolants with chlorine content and belong to such gases to a much greater extent than the notorious carbon dioxide.
Even more dangerous for the atmosphere of the planet is the ability of refrigerants with chlorine to destroy the ozone layer of the Earth.
Therefore, at the end of the last century, at the international level, decisions were made to reduce and even ban the manufacture and use of refrigerants, which in one way or another destroy the ozone layer of our planet.
Classification of refrigerants for environmental impact and current trends in their production and use
Just the ability of the refrigerant to influence the formation of the greenhouse effect and the ozone layer and led them to classify them according to the properties.
- The most dangerous in this respect are freons CFC chlorofluorocarbons with the highest ozone-depleting ability. This group includes refrigerants R11, R12, R502. Freon R11 has been banned since 1996. Two others are partly used in household refrigerators and low-temperature refrigeration units, but the production of equipment working on refrigerants in most developed countries at the moment is also discontinued.
- HCFC - a group of hydrochlorofluorocarbons, - refrigerants with low ozone-depleting activity. It includes R21, R123, R124, R141B, R142B and the most commonly used in the production of household air conditioners freon R22 until recently. The threat of further destruction of the ozone layer has prompted the international community to take a decision on the phasing out of the use of this group of refrigerants, with a complete replacement of them for safe species. So, the production of domestic air conditioners in the EU countries, the USA, Canada and Japan at Freon R22 is no longer implemented.
- For today, the most promising in terms of ecology is the use of ozone-friendly refrigerants. These include freons containing no chlorine, a group of HFCs, as well as alternative refrigerants that are actively developed in developed countries.
The HFC group includes freons R125, R132, R134a, R152a, R32, R600, R717, and others.
Alternative refrigerants can be either pure substances or mixtures of other freons in appropriate proportions. For example, a known substitute for freon R22 in domestic air conditioners, - the refrigerant R410A is a mixture of two safe freon R32 and R125 in the proportion of 50/50. This imposes certain nuances on the service and repair of this technique, because even with partial leakage freon need to completely change the refrigerant. However, the technical indicators and the cost-effectiveness of such equipment is an order of magnitude higher.