What Are Different Types of Refrigerant Gas?

21 10 月, 2024
3:08 上午

A refrigerant is a substance used in cooling systems to transfer heat, and it is widely used in air conditioners, refrigerators, and other cooling equipment. Its main function is to absorb heat from the environment and release it at another location, thereby achieving a cooling effect. Refrigerants typically accomplish this process through reversible phase changes, such as gas-liquid phase changes.

An ideal refrigerant is non-toxic, non-explosive, non-corrosive to metals and non-metals, non-flammable, easy to detect when leaking, chemically stable, non-destructive to lubricating oil, has a high latent heat of evaporation, and is harmless to the environment.

Which refrigerant meets these criteria as an ideal refrigerant in the industry? Let’s delve into different types of refrigerant gas to get the answer in this article.

How are refrigerants named?

Before introducing the types of refrigerants, we will introduce their naming rules first so that you can identify the refrigerant models in the following articles.

General Standard

The designation for refrigerants was initially established for Freon, and the globally accepted standard at that time was set by the American Society of Heating, Refrigerating and Air-Conditioning Engineers in 1967 (ASHRAE Standard 34-67). If you know the chemical formula of a refrigerant, you can determine its designation. The designation consists of the letter “R” followed by numbers. “R” stands for refrigerant (refrigeration medium), while previously “F” stood for Freon. Internationally recognized designations use “R” when referring to refrigerants. For example, the designation for difluorochloromethane is R22.

There are many types of refrigerants, and the naming rules differ among these types.

1. Halogenated Hydrocarbons and Alkane Refrigerants

The molecular formula for alkane compounds is CmH2m+2; for halogenated hydrocarbons, it is CmHnFxClyBrz where 2m+2=n+x+y+z. Their shorthand notation is designated as R(m−1)(n+1)(x)B(z). For example, difluoro chloromethane, with the molecular formula CHF₂Cl, has m−1=0, n+1=2, x=2, and z=0 z=0, thus its designation is R22.

2. Inorganic Compound Refrigerants

For example, ammonia is designated as R717 (molecular formula NH₃). The “7” represents inorganic compounds, and 17 is the integer part of its molecular weight. Carbon dioxide is designated as R744 (molecular formula CO₂).

3. Azeotropic Mixture Refrigerants

These are mixtures of two or more completely miscible single refrigerants mixed in a certain proportion at room temperature. The shorthand notation for azeotropic mixture refrigerants is R5( ), where the parentheses contain a series of numbers representing the order in which the refrigerant was named, starting from 00.

4. Non-Azeotropic Mixture Refrigerants

These are solutions formed by mixing two or more immiscible single refrigerants. The shorthand notation for non-azeotropic mixture refrigerants is R4( ), where the parentheses contain a series of numbers representing the order in which the refrigerant was named, starting from 00.

Different Refrigerant Types Classified by Halogen Molecules

There are many standards for classifying refrigerants. The most common and widely used method is classification based on halogen molecules, which divides refrigerants into CFC, HCFC, HFC, and HFO categories.

1. CFC Refrigerants

Chlorofluorocarbons, abbreviated as CFC refrigerants, contain chlorine (Cl), fluorine (F), and carbon (C), but no hydrogen (H). They have high Ozone Depletion Potential (ODP) and Global Warming Potential (GWP) values.

Common Used CFC Refrigerant

For examples, R11, R12, R113, R114, R115, R500, R502, and others.

The Impact of CFC Refrigerant

CFCs are the first generation of chlorofluorocarbon refrigerants. While they have strong performance, they do badly in protecting the environment. When CFCs enter the atmosphere, they release chlorine atoms that have strong oxidative properties, which break down O₃ in the ozone layer, directly leading to its depletion.

In 1977, a British scientific expedition discovered an ozone hole over Antarctica. To address the damage caused by CFCs to the ozone layer, 26 United Nations member countries signed the Montreal Protocol in 1987. This agreement aimed to protect the ozone layer and atmospheric environment by gradually phasing out the use of CFCs. It uses Ozone Depletion Potential (ODP) and Global Warming Potential (GWP) as important indicators for assessing the environmental friendliness of fluorinated gases.

GWP is a metric used to measure the impact of fluorinated gases on climate warming, using carbon dioxide as a baseline. Carbon dioxide is assigned a GWP of 1, and other substances are calculated relative to this. For example, R134a has a GWP of 1300, meaning that emitting one kilogram of R134a into the atmosphere is equivalent to emitting 1300 kilograms of carbon dioxide.

Currently, the global phase-out of CFCs has been completed.

2. HCFC Refrigerants

Hydrochlorofluorocarbon refrigerants, abbreviated as HCFCs, contain chlorine (Cl), fluorine (F), carbon (C), and hydrogen (H). They have low Ozone Depletion Potential (ODP) but high Global Warming Potential (GWP).

Common HCFC Refrigerants

These mainly include refrigerants R22, R123, R141b, R142b, and others.

HCFCs are the second generation of fluorinated refrigerants. They replace some chlorine atoms in CFCs with hydrogen atoms, significantly reducing the ODP. Their ozone depletion potential is only a fraction of that of R11. Therefore, China’s national plan for phasing out ozone-depleting substances considers HCFCs as the most important transitional substitutes for CFCs.

Although HCFCs reduce ODP by an order of magnitude, they still do not completely eliminate damage to the ozone layer.

3. HFC Refrigerants

Hydrofluorocarbon refrigerants, abbreviated as HFCs, contain fluorine (F), carbon (C), and hydrogen (H). They are the third generation of fluorinated refrigerants, replacing all chlorine atoms in HCFCs with hydrogen atoms, resulting in zero ODP, thus completely resolving the issue of ozone depletion. However, HFCs have very high GWP, which increasingly contributes to global climate warming.

Common HFC Refrigerants

These mainly include refrigerants R134a, R125, R32, R407C, R410A, and R152a.

4. HFO Refrigerants

To reduce HFC’s impact on climate warming, developing the next generation of environmentally friendly fluorinated gases is urgent. As a leading supplier of fluorinated gases, LECRON SHARE is actively involved in the application development of fourth-generation fluorinated gases, creatively developing hydrofluoroolefins, abbreviated as HFOs.

Common HFO Refrigerants

These include HFO-1234yf, HFO-1234ze, and HFO-1233zd.

HFO refrigerants contain fluorine, carbon, and hydrogen, with zero ODP, meaning they do not harm the ozone layer. Additionally, HFOs have a unique double-bond structure that allows them to break down quickly in the atmosphere, with an atmospheric lifetime of only a few weeks. This results in an ultra-low GWP, having minimal impact on climate warming. For example, while HFC-134a (GWP 1300) has an atmospheric lifetime of over 14 years, HFO-1234yf (GWP < 1) has a lifetime of less than 28 days.

The excellent environmental performance of HFOs makes them ideal replacements for HCFCs and HFCs.

Conclusion

The choice of refrigerants significantly impacts both the ozone layer and global warming potential, making it essential to opt for options that minimize environmental harm. As the world becomes increasingly aware of climate change and its effects, the transition to environmentally friendly refrigerants is not just a regulatory requirement but a moral imperative.

LECRON SHARE, as one of the leading refrigerant suppliers in China, will also contribute to the innovations in low-GWP refrigerants, such as hydrofluoroolefins (HFOs) . If you are interested in our HFO, HFC, HCFC refrigerant products, feel free to contact us to get more information!

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