Types and differences of various refrigerants

　　【】1, R22 is widely used in our country. Some experts believe that if R123 can finally lift the ban, then the day when R22 is lifted will not be far away. They are also working hard, hoping to also classify R22 as an environmentally friendly refrigerant, thinking that it is comprehensive in terms of environmental protection, safety, efficiency, etc. Considering that R22 is an excellent refrigerant for z*, and the destruction of the ozone layer and the greenhouse effect are not just the influence of refrigerants. R22 cannot be eliminated due to choking. Some experts in my country pointed out that my country’s ability to use R22 to 2040 was achieved at political and diplomatic costs. If R22 is now banned in advance according to the requirements of certain manufacturers, the impact on the economy will be too great. Refrigerants and lubricants Both need to be imported, because our country is irresponsible to itself; besides, the fate of R123 and R22 is not yet certain.

　　2, R123, like R22, is also an HCFC refrigerant. Now some manufacturers are promoting R123 as a substitute for R22. In addition, these manufacturers use R123 to run under negative pressure in the evaporator of the refrigeration system and have less leakage as the reason. They are trying their best to work with related departments, hoping to classify R123 as an environmentally friendly refrigerant.

　　3, R134az* first appeared as a substitute for R12. Its thermophysical properties and unit volume cooling capacity are similar to R12. Now it has been widely used in places such as heat pump units and household refrigerators. R134a is also mainly used as refrigerant in chillers. However, because its volumetric cooling capacity is only 2/3 of R22 (smaller when the evaporating temperature is lower than -23°C), it is not widely used in positive displacement compressors. In addition, R134a has a GWP of 1600, especially TEWI is higher than R22, which is a refrigerant restricted by the Kyoto Protocol. In addition, when the evaporation temperature is lower than -15°C, R134a is not recommended.

　　4, R407C is a mixed refrigerant composed of 23% R32, 25% R125 and 52% R134a by mass percentage. z* first appeared as a substitute for R22 and received a lot of attention before 2002, but it has not been popular in recent years. Theoretically speaking, the thermal physical properties of R407C are similar to R22. However, as a mixed refrigerant, R407C has a temperature drift of 7°C. In a small, air-cooled refrigeration system, it can make good use of its temperature drift characteristics to improve the system However, this feature cannot be used well in large-scale refrigeration systems. The actual cooling capacity and COP of similar units are more than 10% lower than R22 units, and the mass transfer resistance is large, and the heat exchange is relatively poor, so It is difficult to be favored, and it is basically no longer used in recent years.

　　5, R410A is a mixed refrigerant composed of 50% R32 and 50% R125 by mass percentage. Although R410A is a non-azeotropic refrigerant, its slip temperature is only about 0.1°C, which can almost be counted as an azeotropic refrigerant. Z* was not widely accepted at first because of the high pressure, but it has attracted much attention in the past two years. The refrigeration capacity per unit volume of R410A is about 145% of R22, COP is about 5% lower than R22, GWP and TEWI are not too high, originally it is a good alternative refrigerant, but because of the high pressure, at the same temperature, saturation The pressure is about 50% higher than the saturation pressure of R22, which leads to safety and material issues that need to be resolved. According to the current development trend, R410A should be paid more and more attention in the next few years. At present, it is mainly used on small units.

　　6, R404A is a mixed refrigerant composed of 44% R125, 52% R143a, and 4% R134a according to mass percentage. The slip temperature is about 0.6°C. At the same temperature, the saturation pressure is about 5-10% higher than that of R22. The volumetric cooling capacity of R404A is about 5% higher than that of R22, but the COP is about 5-10% lower than that of R22. There are more applications in the case of low evaporation temperature.

　　7, R134a, R407C, R404A, R410A, and R507 need to use synthetic oil, such as POE oil. Such oils and refrigerants are highly hydrophilic. The use of these alternative refrigerants greatly increases the requirements for operation and maintenance.

　　 8. CFCs (chlorofluorocarbon): fully halogenated, without hydrogen in the molecule. Due to the presence of fluorine atoms, the molecules are stable, have a long life in the atmosphere, and will diffuse to the stratosphere. Cl causes the destruction and attenuation of the ozone layer. (Such as R11, R12, R113).

　　9, HCFCs (hydrochlorofluorocarbon): Partially halogenated, the molecule can contain hydrogen, chlorine, and fluorine at the same time. (Such as R22, R123).

　　10, FC (perfluorocarbon fluorocarbon): The molecule contains only carbon atoms and fluorine atoms. (Such as R116, RC318).

　　11, HFC (hydrofluorocarbon): no chlorine freon, part of the halogenated hydrogen in the molecule, does not destroy the ozone layer, ODPu003d0. (Such as R125, R134a, R245).