R11 refrigerant once played a significant role in the refrigeration industry, but it is now being phased out because of environmental concerns. If you work with HVAC systems or industrial cooling, understanding R11 helps you see how refrigerants have evolved and why environmental regulations matter today.
In this guide, you’ll learn what R11 refrigerant is, what characteristics it has, where it was used, and why it has been banned.
What is R11 Refrigerant?
You may hear R11 refrigerant called by different names, including R11, Freon 11, F-11, or CFC-11. Its chemical name is Trichlorofluoromethane (CCl₃F), a type of chlorofluorocarbon (CFC).
In the early days of the refrigeration industry, R11 was one of the most widely used refrigerants. It played a key role in large-scale central air conditioning systems and other industrial cooling equipment.
As environmental concerns grew, the use of R11 is now restricted because of its ozone-depleting properties and contribution to the greenhouse effect.
Today, many developed countries and some developing nations have banned the use of R11 in new systems and restricted its use in existing equipment.
R11 Refrigerant Properties
Physical Properties
At standard temperature and pressure, R11 usually exists in liquid form. Except in very hot conditions, you can store R11 and transport it in ordinary sealed containers. However, when using it, you should keep it away from dust and moisture.
R11 has a relatively high molecular weight of 137.4, which means it delivers less cooling per unit volume. For example, compared to some medium-temperature refrigerants, R11 provides less cooling capacity for the same volume. This is one of the reasons why it is better suited for use in specific large-scale refrigeration equipment.
Here are the physical properties of R11 refrigerant.
| Features | R11 Refrigerant |
| Composition | Trichlorofluoromethane |
| Chemical Formula | CCl₃F |
| Purity | ≥99.8% |
| Molecular Weight | 137.37 g / mol |
| GWP | 4750 |
| ODP | 1.6 |
| Boiling point | 23.8 ℃ |
| Freezing point | -111℃ |
| Critical Temperature | 198.0 ℃ |
| Critical pressure | 4.41 Mpa |
| Liquid specific heat, 30ºC | 0.21 KJ/(Kg·℃) |
| Vapour pressure (25°C) | 102 kPa |
| Safety classification | A1 |
| Packaging sizes | Steel drum 250kg/200L |
Chemical Properties
In terms of chemical properties, R11 has a certain degree of stability. Under normal temperature and pressure conditions, it does not easily react with other substances.
However, it is important to note that R11 must not come into contact with open flames. When R11 comes into contact with an open flame, it becomes dangerous. Because the R11 molecule contains three chlorine atoms, it can break down into highly toxic phosgene gas when exposed to an open flame.
Phosgene is an extremely toxic gas that can cause severe damage to the human respiratory and nervous systems, and may even be life-threatening. Therefore, in facilities such as machine rooms where R11 refrigerant is used, open flames and high-temperature operations must be avoided to prevent dangerous accidents.
R11’s solubility in water and oil is similar to that of the common R12 refrigerant, and its corrosiveness to metals is also comparable to R12. Under normal operating conditions, it does not cause significant corrosion damage to metal equipment.
Advantages of R11 Refrigerant
Stable and Reliable Performance
In the early stages of refrigeration technology development, R11 possessed unique advantages that made it an ideal choice for specific refrigeration applications. As a high-temperature refrigerant, R11 has a high boiling point. You can use it in systems that require higher evaporation temperatures.
For example, in centrifugal chillers used in large central air conditioning systems, R11 meets the system’s refrigerant requirements and effectively achieves the desired cooling performance.
In these large-scale systems, R11’s physical and thermodynamic properties align with the equipment’s design and operating parameters.
Good Heat Transfer Properties
R11 has heat transfer properties similar to those of R12, enabling efficient heat transfer in refrigeration systems.
In heat exchange equipment such as evaporators and condensers, R11 refrigerant can effectively absorb or release heat, which improves system efficiency. Its excellent heat transfer properties allow refrigeration equipment to operate at relatively low pressures and temperatures, reducing energy consumption and lowering operating costs. This helps reduce operating costs for large-scale refrigeration projects with specific energy efficiency requirements.
Convenient for Storage and Transportation
Since R11 is liquid at standard temperature and pressure, it can be stored and transported in ordinary sealed containers, except during high-temperature periods such as summer. This characteristic makes the transportation and storage of R11 relatively straightforward, requiring no special equipment or conditions.
Compared to some refrigerants that must be stored and transported under high-pressure or low-temperature conditions, R11 has lower storage and transportation costs and is more convenient to handle. This contributed to the widespread adoption of R11 in the early refrigeration market.
Disadvantages of R11 Refrigerant
High Ozone Depletion Potential (ODP)
R11 belongs to the CFC (chlorofluorocarbon) class, which is a Class 1 ozone-depleting substance (ODS). It is the reference value used to measure ozone depletion caused by refrigerants.
It has a significant destructive effect on the ozone layer. When released into the atmosphere, R11 gradually rises into the stratosphere. In the stratosphere, when exposed to ultraviolet radiation, R11 breaks down into chlorine atoms, which react with ozone molecules and destroy the ozone layer.
The thinning or disappearance of the ozone layer leads to increased ultraviolet radiation reaching the Earth’s surface, leading to serious environmental problems, such as an increase in human skin cancer and cataract incidence, crop damage and reduced yields, and disruption of the ecological balance. Furthermore, R11 contributes to the greenhouse effect, exacerbating the trend of global warming.
High Toxicity
R11 is slightly more toxic than R12 and is more prone to decomposing into highly toxic phosgene when exposed to open flames, which can put your safety at risk. During the installation, maintenance, and operation of refrigeration equipment, improper handling leading to an R11 leak—especially when exposed to open flames or high-temperature environments—can result in phosgene poisoning incidents.
Therefore, strict safety measures must be implemented when using R11 refrigerant, such as enhancing ventilation in equipment rooms and providing protective equipment, which increases both operating costs and operational complexity.
Low Cooling Capacity
Due to R11’s relatively high molecular weight, its cooling capacity per unit volume is relatively low. This means that to meet the same cooling capacity requirements, a larger volume of R11 refrigerant is needed, thereby increasing the size and weight of the refrigeration system.
In applications with strict restrictions on equipment size and weight—such as vehicle air conditioning systems—the use of R11 is somewhat limited. Furthermore, the increased volume and weight also raise manufacturing and transportation costs.
Why Has R11 Refrigerant Been Phased Out?
R11 is a class ozone-depleting substance (ODS). Because of its high ozone depletion potential (ODPc=1.00）, the production and consumption of R11 were phased out under the Montreal Protocol in most countries.
Today, R11 is only found in some legacy centrifugal chillers and specialised industrial systems.
Regulations Concerning R11 Refrigerant
As global concern for environmental protection continues to grow, reducing the use of substances that deplete the ozone layer is now a global priority. R11 has a high ozone depletion potential (ODP), which means it can seriously damage the ozone layer.
Because of this, it has been banned in many countries under international agreements. This has greatly limited the use of R11 in the refrigeration sector, leading to its gradual replacement by environmentally friendly refrigerants.
The Montreal Protocol
Developed Countries: Production and consumption of CFCs such as R11 were completely phased out as of January 1, 1996.
Developing Countries: The final phase-out date was 2010, but many developing countries completed the phase-out ahead of schedule.
United States
The U.S. Environmental Protection Agency (EPA), in accordance with regulations such as the American Innovation and Manufacturing Act, has imposed restrictions on the use of refrigerants like hydrofluorocarbons (HFCs).
Although these regulations primarily target HFCs, they reflect the U.S. government’s emphasis on and promotion of environmentally friendly refrigerants.
With the phase-out of CFCs and HCFCs, the use of refrigerants such as R11 in the U.S. market has significantly decreased. At the same time, the United States encourages companies to research, develop, and adopt more environmentally friendly refrigerant alternatives.
European Union
F-Gas Regulation: The European Union has enacted strict F-Gas regulations that restrict the use of hydrofluorocarbons (HFCs). Although the regulation primarily targets HFCs, the EU is also actively promoting the phase-out of ozone-depleting substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).
In the EU market, refrigeration equipment containing controlled substances such as R11 is subject to strict restrictions, and its import and sale are even prohibited.
What Refrigerants Can Replace R11 Refrigerant?
Since R11 has been phased out due to its high ozone depletion potential, you can no longer use it in new refrigeration and chiller systems. If you are maintaining older equipment, several refrigerants can serve as alternatives depending on your system design and performance requirements.
The best replacement depends on factors such as cooling capacity, operating pressure, energy efficiency, and environmental regulations.
| Replacement | ODP | GWP | Typical Use |
|---|---|---|---|
| R123 | 0.02 | 77 | Existing centrifugal chillers |
| R245fa | 0 | 1030 | Industrial chillers |
| R514A | 0 | 2 | New low-GWP chillers |
R11 vs R123
R11 and R123 are both low-pressure refrigerants commonly used in centrifugal chillers. However, R123 was developed as a replacement for R11 because it has a much lower impact on the ozone layer and the environment.
While both refrigerants offer similar operating characteristics, R123 provides a safer long-term solution for maintaining older chiller systems and meeting environmental regulations.
| Property | R11 | R123 |
|---|---|---|
| Chemical Formula | CCl₃F | CHCl₂CF₃ |
| Refrigerant Type | CFC | HCFC |
| ASHRAE Safety Class | A1 | B1 |
| ODP | 1.0 | 0.02 |
| GWP | 4,750 | 77 |
| Boiling Point | 23.8°C | 27.8°C |
| Flammability | Non-Flammable | Non-Flammable |
| Environmental Status | Phased Out | Transitional Replacement |
Applications of R11 Refrigerant
Large-Scale Central Air Conditioning Systems
In the early days, R11 was primarily used in refrigeration equipment such as centrifugal chillers for large-scale central air conditioning systems. These systems are typically installed in large commercial buildings, industrial facilities, and buildings with high cooling capacity.
R11’s high-temperature refrigeration characteristics and excellent heat transfer properties enable it to meet the demands of these large-scale systems. For example, in large shopping malls and hotels, centrifugal chillers use R11 as a refrigerant to cool and regulate indoor air.
Other Industrial Applications
In addition to large-scale central air conditioning systems, R11 is also used in various other industrial sectors. For instance, it is widely used as a blowing agent for polyurethane foam.
During the production of polyurethane foam, R11 acts as a physical blowing agent. The gas generated by its vaporisation causes the polyurethane foam to expand, forming a foam material with a specific pore structure and performance characteristics. This foam material is extensively used in building insulation, furniture manufacturing, and other fields.
Additionally, R11 serves as an extractant, solvent, and dry cleaning agent, playing a significant role in industries such as chemicals and textiles.
Conclusion
R11 refrigerant is no longer used in modern systems, but you may still find it in older equipment. Knowing its risks and regulations helps you handle it safely and choose better alternatives.
If you want to know about eco-friendly refrigerants and drive the refrigeration industry toward a greener and more sustainable future, you can contact me. I will give you some suggestions.
FAQ
Is R11 refrigerant still used today?
No. R11 production has been phased out in most countries under the Montreal Protocol. Today, it is mainly available through reclaimed or recycled supplies for servicing older equipment.
Why is R11 banned?
R11 damages the ozone layer. It releases chlorine atoms that break down ozone in the atmosphere.
What refrigerants replace R11 refrigerant？
Common R11 replacements include R123, R245fa, and newer low-GWP refrigerants such as R514A, which have lower environmental impact.
Is R11 dangerous?
R11 is low in toxicity under normal conditions. However, if it is exposed to an open flame, it can form toxic phosgene gas.
Can you still buy R11 refrigerant?
In most countries, new R11 refrigerants are no longer produced. Only recycled or reclaimed R11 may be available under strict regulations.
Can you retrofit R11 refrigerant?
In some cases, older centrifugal chillers can be retrofitted to use R123 or other alternatives, but modifications to the equipment and manufacturer approval are usually required.
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