4 Refrigerant Types and Some Related Knowledge
Refrigerant is the work substance in the refrigeration system. More than 80 kinds of substances can be used as refrigerants. The most common refrigerant types are Freon (including R22, R134a, R407c, R410a, R32, etc.), ammonia (NH3), water (H2O), carbon dioxide (CO2), a small number of hydrocarbons (such as R290, R600a).
In this article, we talk about several refrigerant types
1. Usually, according to the condensing pressure and standard evaporation temperature of the refrigerant, it is divided into three refrigerant types: high, medium, and low temperature. (Standard evaporation temperature refers to the evaporation temperature at standard atmospheric pressure, which is the boiling point.)
- High temperature (low pressure): Standard evaporation temperature (tS)>0℃, condensation pressure (PC)≦0.2～0.3Mpa, commonly used R123, etc.
- Medium temperature (medium pressure): 0℃>tS>-60℃, 0.3Mpa<2.0Mpa, commonly used are ammonia, R12, R22, R134a, propane, etc.
- Low temperature (high pressure): tS≦-60°C, commonly used are R13, ethylene, R744 (CO2), etc.
2. According to the chemical composition, refrigerants can be divided into five refrigerant types: inorganic compound refrigerants, freon, saturated hydrocarbon refrigerants, unsaturated hydrocarbon refrigerants, and azeotropic mixture refrigerants.
- Inorganic compounds. Water, ammonia, carbon dioxide, etc;
- Derivatives of saturated hydrocarbons, commonly known as Freon. Mainly derivatives of methane and ethane. Such as R12, R22, R134a, etc;
- Saturated hydrocarbons. Such as propane, isobutane, etc;
- Unsaturated hydrocarbons. Such as ethylene, propylene, etc;
- Azeotropic mixed refrigerant. Such as R502, etc;
- Non-azeotropic mixed refrigerants. Such as R407c, R410, etc.
3. In daily use or sales, refrigerant types are often divided into CFC, HCFC, HFC, HC, PFC, and HFO according to environmental impact.
- CFC Refrigerant – chlorofluorocarbon products, referred to as CFC. Mainly including R11, R12, R113, R114, R115, R500, R502, etc., due to the destructive effect on the ozone layer and the largest, it is listed as a class of controlled substances by the “Montreal Protocol.”
- HCFC Refrigerant – hydrochlorofluorocarbon products, referred to as HCFC. Mainly including R22, R123, R141b, R142b, etc., the ozone depletion coefficient is only a few per cent of R11; chlorine, hydrogen, and low-pollution substances are transitional.
- HFC Refrigerant – hydrofluorocarbons: referred to as HFC. Mainly including R134A, R125, R32, R407C, R410A, R152, etc., the ozone layer destruction coefficient is 0, but the climate warming potential value is very high.
- HC Refrigerant—hydrocarbon, chlorine-free, fluorine-free, and pollution-free can be used as a substitute. Hydrocarbon refrigerants mainly have the two advantages of energy saving and environmental protection: air conditioners using hydrocarbon refrigerants can save energy consumption by about 15% to 35% compared with R134 and R22 air conditioners. Environmental protection: hydrocarbon refrigerants are natural working fluids, so they have no pollution to the atmosphere, no damage to the ozone layer, and almost zero greenhouse effect.
- PFC Refrigerants are fully halogenated hydrocarbons. They only contain fluorine (F) and carbon (C). Mainly include PFC-14, PFC-116, PFC-218.
- HFO Refrigerants – It is the fourth generation of fluorine-based refrigerants. HFC refrigerants comprise hydrogen, fluorine, and carbon atoms, and single bonds connect the atoms. HFO refrigerants are also composed of hydrogen, fluorine, and carbon atoms. The ODP of HFO refrigerants is also 0, with a low GWP value.
4. According to the safety level of the refrigerant
Refrigerants should have acceptable safety, which mainly includes toxicity and flammability, so generally, according to the corresponding standards, the toxicity of refrigerants is also divided into Class A (low chronic toxicity) and Class B (high chronic toxicity). The flammability is divided into category 1 (no flame propagation), category 2L (weakly flammable), category 2 (flammable), and category 3 (flammable and explosive). Safety is subdivided into 8 categories, namely: A1, A2L, A2, A3, B1, B2L, B2, and B3, among which A1 is the safest and B3 is the most dangerous.
- Category A1: R11, R12, R13, R113, R114, R115, R116, R22, R124, R23, R125, R134a, R227ea, R236fa, R1233zd(E), R1336mzz(Z), R218, RC318, R401a, R401b, R402a, R402b, R403a, R403b, R404a, R407a, R407b, R407c, R407d, R408a, R409a, R410a, R417a, R422d, R500, R501, R502, R507a, R508a, R508b, R509a, R513a, R744
- Category A2: R142b, R152a, R406a, R411a, R411b, R412a, R413a, R415b, R418a, R419a, R512a
- A2L category: R143a, R32, R1234yf, R1234ze(E)
- Category A3: R290, R600, R600a, R601a, R1270, RE170, R510a, R511a
- Category B1: R123, R245fa
- B2L category: R717
How to choose refrigerant?
Refrigerant selection should have good thermodynamic properties, physical and chemical properties, and excellent environmental characteristics. You can refer to the following principles:
1) No damage to the human ecological environment. Does not destroy the ozone layer of the atmosphere and does not produce a greenhouse effect.
2) The critical temperature is higher. The refrigerant can liquefy at normal temperature or ordinary low temperature. It is hoped that the critical temperature is much higher than the ambient temperature to reduce the refrigerant’s throttling loss and improve the circular economy.
3) Within the operating temperature range, there should be an appropriate saturated vapour pressure; at least, the evaporation pressure should not be lower than the atmospheric pressure to prevent external air from infiltrating into the system; the condensation pressure should not be too high; otherwise, it will cause increased power consumption of the compressor, and require The system has a higher pressure bearing capacity, which increases the equipment cost.
4) Large cooling capacity per unit volume. Can reduce compressor gas delivery.
5) Low viscosity and density. Reduce flow resistance losses in the system.
6) High thermal conductivity. The heat transfer coefficient of the heat exchanger can improve, and the heat exchange equipment’s heat transfer area and material consumption can reduce.
7) No burning, no explosion, non-toxic. It does not corrode metal materials, has no chemical effect on lubricating oil, and does not decompose under high temperatures.
8) The isentropic index is small. It can reduce the exhaust temperature and power consumption in the compression process and is conducive to safe operation and improved service life.
9) The solidification temperature is low. Avoid freezing at evaporating temperatures.
10) Has good insulation properties.
11) The price is low and easy to obtain.
12) The compression work per unit volume is small.
In actual selection, having a refrigerant that fully meets the above requirements is difficult. Generally, it should be fully considered according to the application conditions and your specific situation. Fluorine refrigerants, such as small hermetic compressors, are often used for household installations. Ammonia is mostly used in large-scale industrial refrigeration, and hydrocarbons are mostly used in the petrochemical industry.
The above are several refrigerant types and selection principles of refrigerants. If there are any inaccurate descriptions or questions about refrigerant sales, please leave a message to contact us.