Short Answer- The HVAC industry has undergone substantial changes in refrigerant usage, with a shift towards environmentally friendly options. Refrigerants, whether in liquid or gas form, play a crucial role in cooling systems by absorbing and releasing heat. The Different Types of Refrigerants in HVAC: Most Common List includes R-12, R-22, R-32, R-134A, R-404A, R-407C, R-410A, and R-454B. While some older refrigerants like R-12 and R-22 have been phased out due to their environmental impact, newer alternatives like R-32 and R-454B offer better efficiency and reduced environmental harm.
The HVAC (Heating, Ventilation, and Air Conditioning) industry has seen a significant evolution in the types of refrigerants used over the years. As technology advances and environmental concerns grow, the industry has been shifting towards more eco-friendly refrigerants. Here we explain the different types of refrigerants in HVAC: the most common list used in HVAC systems, along with a brief overview of each of these.
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Introduction to Different Types of Refrigerants
A refrigerant is an element in the form of a liquid or a gas. A specific area in the refrigeration system cools down using the refrigerant. The process seizes heat from space and then releases it into another space. This is the act of a refrigerant.
Refrigerants in refrigerating systems (air conditioners) absorb heat and release heat. Apart from this, Thermodynamic phenomena of phase change are also used by refrigerants. This helps the liquid convert to gas and gas into a liquid.
The process of refrigerant starts in the evaporator component of the system. The refrigerant liquid will absorb heat and change to vapor under low pressure. The vapor travels to the compressor component of the system.
The compressor pressure and temperature tend to increase. The release of heat from the vapor happens at this stage. The release of heat happens in the condenser component.
The refrigerant then changes back to liquid form. It travels back to the evaporator. Repetition of the process happens again and again with the same liquid. There are different types of refrigerants.
Modern refrigerant equipment includes ACs, cooling systems, freezers, and refrigerators. Despite their usefulness, refrigerants also contribute to global warming.
Different Types of Refrigerants In HVAC:
The classification of refrigerants into different groups is due to their chemical composition. The most common refrigerants include Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs), Hydrofluorocarbons (HFCs), and Natural Refrigerants. Freon or halocarbons are synthetically produced. The classification also depends on their chemical elements, Chlorine (CL), Hydrogen (H), Carbon (C), and Fluorine (F).
- Chlorofluorocarbons (CFCs) – R11, R12, R113, R114, R115
- Hydrochlorofluorocarbons (HCFCs) – R22, R123
- Hydrofluorocarbons (HFCs) – R134a, R404a, R407C, R410a
The two numbers that characterize all refrigerants are:
- Ozone Depletion Potential (ODP)
A measure of a substance’s ability to harm the ozone layer compared to the reference substance, trichlorofluoromethane (R-11 or CFC-11). A substance with an ODP of 1 has the same ozone-depleting potential as R-11, while an ODP of 0 has no potential to deplete the ozone layer.
The value range of ODP is 0 – 1. ODP closest to 1 is harmful to the ozone layer. CFCs have significant ODP values. This is because they contain chlorine. Currently, CFCs are not used due to their harmful environmental impact.
- Global Warming Potential (GWP)
A measure of how much heat a greenhouse gas traps in the atmosphere compared to the amount trapped by carbon dioxide (CO2) over a specific period, typically 100 years. A substance with a GWP of 1 has the same climate impact as CO2, while a substance with a higher GWP has a greater impact.
GWP value ranges from 0 to several thousand. If the GWP value is high, the refrigerant is more harmful and can cause global warming. Inorganic refrigerants like carbon dioxide and ammonia have small GWP values. HCFCs are being phased out. The only HCFCs allowed nowadays are those without chlorine.
The different types of refrigerants that make the most common list include:
- R-12
- R-22
- R-32
- R-134A
- R-404A
- R-407C
- R-410A
- R-454B
1. R-12
R-12 has had a significant impact on the evolution of air conditioning and refrigeration systems. It is a colorless gas at room temperature and atmospheric pressure, transitioning into a liquid when subjected to pressure or cooler temperatures. In the past, R-12 was highly favored because of its excellent thermodynamic performance, which made it extremely efficient as a refrigerant.
Before it was phased out, R-12 was commonly used in automotive air conditioning, household refrigerators, and some commercial refrigeration applications. Under normal conditions, R-12 is non-flammable and exhibits low toxicity, which contributed to its popularity. However, when exposed to extreme heat or open flames, R-12 can break down and produce toxic byproducts such as phosgene gas, which poses a serious health hazard if inhaled.
Working with or around R-12 demands adequate ventilation and strict adherence to safety protocols. Due to its negative effects on the ozone layer, the production and usage of R-12 were officially phased out under the Montreal Protocol, an international agreement aimed at protecting the ozone layer. By the mid-1990s, R-12 had largely been replaced by R-134a, especially in the automotive air conditioning sector, as R-134a does not contain ozone-depleting substances.
In other applications, various environmentally safer refrigerants have been introduced depending on system-specific requirements. If you are operating a legacy system that still uses R-12, it is crucial to handle it responsibly. Ensure there are no leaks or unauthorized releases into the atmosphere. During servicing or system disposal, the R-12 refrigerant must be captured, recycled, or reclaimed in compliance with local environmental regulations and safety guidelines.
2. R-22
R-22 is another refrigerant that has been extensively used throughout the HVAC industry, particularly in residential and commercial air conditioning systems. Like R-12, R-22 exists as a colorless gas under normal atmospheric conditions, and it transforms into a clear, colorless liquid when cooled or compressed. Its thermodynamic efficiency made it ideal for numerous cooling applications.
R-22 was once the primary refrigerant used in residential heat pumps, central air conditioning systems, and even in cold storage units. Though it is less damaging to the ozone layer compared to earlier refrigerants such as R-12, R-22 still contains chlorine, a compound that contributes to ozone depletion.
When released into the atmosphere, the chlorine in R-22 breaks down ozone molecules in the stratosphere, which weakens the protective ozone layer and allows more harmful UV radiation to reach the Earth. Moreover, R-22 is a potent greenhouse gas, meaning its emissions also contribute to climate change and global warming.
Owing to these environmental risks, the production and import of R-22 were phased out under the Montreal Protocol, a global initiative to limit substances that deplete the ozone layer. For instance, in the United States, the complete phase-out of R-22 was finalized by 2020. However, it is still possible to service older systems with recycled or stockpiled R-22, although it is becoming increasingly scarce and expensive.
3. R-32
R-32 is a modern refrigerant that is gaining attention as a more eco-friendly and energy-efficient alternative in the HVAC industry. It remains a colorless gas at room temperature and standard pressure but becomes a liquid when compressed or cooled. Unlike older refrigerants such as R-22 and R-410A, R-32 is mildly flammable, which necessitates new safety guidelines for storage, handling, and usage.
Despite its flammability, R-32 can be safely used in air conditioning systems with the proper equipment and procedures in place. It is utilized both as a standalone refrigerant and as a component in refrigerant blends. A well-known blend is R-410A, which consists of 50% R-32 and 50% R-125. However, since R-125 has a higher global warming potential (GWP), the industry is increasingly shifting toward using pure R-32, particularly in split AC systems.
R-32 offers multiple advantages, including higher cooling efficiency, lower environmental impact, and lower GWP, making it a viable choice for the future of sustainable air conditioning solutions. As the HVAC sector continues to prioritize eco-friendly innovations, R-32 is expected to play a crucial role in shaping energy-efficient and ozone-safe cooling technologies.
4. R-134A
R-134A, commonly known as Norflurane, is a haloalkane refrigerant with exceptional thermodynamic properties. It is a single-component refrigerant, unlike R-22 or R-12, which are blends. This simplifies its recovery and recycling process, as there is no need for specialized equipment to separate different refrigerant components.
The Environmental Protection Agency (EPA) mandates that devices handling refrigerant blends must use separate recovery machines for each component. In contrast, R-134A does not require such differentiation, streamlining its use.
R-134A is the only approved refrigerant alternative for retrofitting old R-12 automotive air conditioning systems across all vehicle types. However, the retrofitting process must be executed with caution. It typically involves replacing the dryer/receiver or accumulator, removing old compressor oil, and changing the high-pressure switch. If the system isn’t thoroughly flushed, cross-contamination with residual R-22 can occur, significantly reducing system reliability.
Such contamination can cause the compressor’s head pressure to increase to dangerous levels, potentially leading to system failure. R-134A uses a specialized oil—either polyol ester (POE) or polyethylene-based oil—designed for compatibility. Due to its environmentally favorable profile and non-ozone-depleting nature, R-134A remains a preferred choice in both automotive and light commercial refrigeration systems.
5. R-404A
R-404A serves as a safe and efficient alternative to R-22 and is widely utilized in commercial refrigeration systems that operate within a temperature range of -45°C to 15°C (-49°F to 59°F). This broad range makes R-404A suitable for applications in the industrial sector and refrigerated transport industry.
It shares many of the same performance characteristics as R-22, but with enhanced stability and safety. R-404A is colorless, odorless, and non-flammable, and it does not react aggressively with water or air. These properties make it a highly reliable option in diverse cooling environments.
Despite its overall safety, users must implement proper safety precautions when handling the refrigerant. Direct skin contact with R-404A can result in frostbite, and exposure to high temperatures or open flames may cause the refrigerant tank to rupture under pressure. R-404A is commonly available in HVAC supply stores that cater to both cooling and heating equipment.
6. R-407C
R-407C is known for its strong thermodynamic performance and is frequently used as a replacement refrigerant for retrofitting systems originally designed for R-22. It is a hydrofluorocarbon (HFC) blend consisting of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134A).
This refrigerant is commonly found in ductless mini-split systems, packaged rooftop air conditioners, water chillers, and direct expansion systems used across residential, commercial, and light industrial properties. It also functions well in medium-temperature refrigeration systems, making it a versatile choice for modern HVAC applications.
Many new appliances and refrigeration systems, especially those shipped with nitrogen as a holding charge, are engineered to be compatible with R-407C. These systems typically use polyol ester (POE) oil, which is specifically formulated for HFC refrigerants.
When retrofitting older R-22 units with R-407C, a complete oil change is necessary to ensure optimal system performance and to prevent any compatibility issues. As a non-ozone-depleting refrigerant, R-407C is considered a more sustainable alternative to Freon and is widely used in new-generation cooling equipment.
7. R-410A
This refrigerant is a blend of difluoromethane, hydrofluorocarbon refrigerants, and pentafluoroethane. R-410A is a non-ozone-depleting refrigerant. It provides more energy efficiency than R-407C and R-22. Chlorine is not even there.
The high refrigeration capacity and pressure make it more suitable than R-22. This helps in providing better performance.
The process of buying an R-410A is easy. Companies that manufacture refrigeration systems and air conditioning make units that use R-410A. R-410A is popular for air conditioning, commercial refrigeration, and chilling units.
The alternative to Freon will not be effective in R-22 a/c units. This is because of the higher pressure in R-410A. The need is for a different pressure gauge than what is usually there in R-22. The charge of the refrigerant is in its liquid form. The charge is only in short bursts.
8. R-454B
R-454B is one of the newer refrigerants introduced to the market as a more environmentally friendly alternative to some of the older, high-GWP refrigerants. It is a blend of two hydrofluoroolefins (HFOs): 68.9% R-32 (Difluoromethane) and 31.1% R-1234yf (Tetrafluoropropene).
It has been designed to closely match the properties of R-410A, making it a potential drop-in replacement in some systems. Furthermore, R-454B does not deplete the ozone layer. It is classified as an A2L refrigerant, meaning it’s of low toxicity (A) and mildly flammable (2L). The mild flammability requires specific handling and installation procedures to ensure safety. However, it can be used safely in various applications with the right precautions.
R-454B is a promising refrigerant that offers a balance between performance and environmental responsibility. As the HVAC industry continues its shift towards more sustainable solutions, refrigerants like R-454B are likely to become more prevalent.
The Future of Refrigerants in HVAC
So there you have it – Different Types of Refrigerants in HVAC: Most Common List.
The HVAC industry is continually evolving, with a clear trend towards environmentally friendly refrigerants. As research continues, we can expect the introduction of newer refrigerants with even lower environmental impacts.
So, when choosing a refrigerant for an HVAC system, it is essential to consider not only its cooling properties but also its environmental impact, safety, and cost. As the industry moves forward, we hope to find a balance that offers efficient cooling while minimizing harm to our planet.
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