If you work with commercial low-temperature refrigeration, you probably know R502. It used to be the go-to refrigerant for medium- and low-temperature systems, and even though it’s being phased out, it’s still a classic you should understand.
Here is what R502 refrigerant is, its properties, its applications, and its limitations and alternatives.
What Is R502 Refrigerant?
R502 refrigerant is a blend of R22 and R115. It was made to perform better in medium- and low-temperature systems. It is HCFC-22 (dichlorodifluoromethane) and CFC-115 (pentachlorofluoroethane) in a mass ratio of 48.8% to 51.2%, and is classified as a hydrochlorofluorocarbon (HCFC) refrigerant.
It was developed to perform better in medium- and low-temperature systems. You’ll find it in older commercial refrigeration equipment, where it delivers reliable cooling.
R502 refrigerant keeps its composition stable during evaporation and condensation, which prevents performance issues common with other blends.
Even as it is phased out due to environmental regulations, understanding its characteristics remains essential for the proper maintenance and replacement of legacy equipment.
Properties of R502 Refrigerant
Physical Properties
As an azeotropic mixture, R502 refrigerant exhibits stable physical properties and distinct characteristics as a refrigerant.
Boiling Point
At standard atmospheric pressure, you’ll notice that R502 has a lower boiling point than R22, making it ideal for freezing applications.
Operating Pressure
Its pressure is moderate, so your compressors and piping don’t need special reinforcement.
The evaporation pressure of R502 refrigerant is higher than atmospheric pressure. When operating a refrigeration system, there is no need to worry about negative pressure developing inside the system.
Cooling Capacity
R502 refrigerant cools more efficiently than R22. If you run a single-stage compressor, your system can get 5–30% more cooling at the same evaporation temperature. In very low temperatures, you’ll see even bigger improvements.
Heat Transfer Efficiency
R502 heat transfer efficiency is high, so your system cools quickly and consistently.
Here is the chart of physical characteristics that make it suitable for high-efficiency refrigeration equipment.
| Physical Properties | R502 |
| Composition | 48.8 % R22 & 51.2 % R115 |
| Other Name | Chlorodifluoromethane, Chloropentafluoroethane |
| Environmental Classification | CFC |
| Molecular Weight (g/mol) | 111.6 |
| Boiling Point (1atm, ℃) | -45.4 |
| Critical Pressure (psia) | 582.8 |
| Critical Temperature (℉) | 177.3 |
| Critical Density (lb./ftˆ3) | 35.5 |
| Liquid Density (70℉, lb./ftˆ3) | 77 |
| Vapor Density (bp.lb./ftˆ3) | 0.388 |
| Heat of Vaporization (bp, BTU/lb.) | 74.2 |
| Specific Heat Liquid (70 ℉, BTU/lb. ℉) | 0.2958 |
| Specific Heat Vapor (1atm, 70 ℉, BTU/lb. ℉) | 0.1641 |
| ODP | 0.249 |
| GWP | 4657 |
| Safety Rating | A1 |
| Oil | MO and alkylbenzene |
Chemical Properties
Chemical Stability
R502 is stable under normal conditions. It won’t react or break down easily. You can safely use it with common metals, seals, and oils in your system, keeping your equipment running reliably.
Decomposition Risks
Avoid high heat or strong oxidizers. R502 may break down, producing harmful gases such as hydrogen fluoride, hydrogen chloride, or even phosgene. During storage and use, it is essential to prevent contact with these adverse factors and ensure proper ventilation and protective measures.
Lubricant Compatibility
R502 mixes well with mineral oils and alkylbenzene oils, so your compressor stays well-lubricated without risk of oil separation. However, it doesn’t dissolve in water, so moisture in the system can create ice plugs and reduce cooling efficiency.
Corrosion Resistance
R502 is non-corrosive to common metals such as copper, iron, and aluminum. It is also compatible with standard rubber seals, helping prevent leaks and extending the life of your equipment.
R502 Refrigerant Pressure Temperature Charts
| Temp (℉) | Temp (℃) | R502 (psig) | R502 (MPa) |
| -40 | -40 | 4.1 | 0.028 |
| -35 | -37.2 | 6.5 | 0.045 |
| -30 | -34.4 | 9.2 | 0.063 |
| -25 | -31.7 | 12.1 | 0.083 |
| -20 | -28.9 | 15.3 | 0.105 |
| -15 | -26.1 | 18.8 | 0.13 |
| -10 | -23.3 | 22.6 | 0.156 |
| -5 | -20.6 | 26.7 | 0.184 |
| 0 | -17.8 | 31.1 | 0.214 |
| 5 | -15 | 35.9 | 0.248 |
| 10 | -12.2 | 41 | 0.283 |
| 15 | -9.4 | 46.5 | 0.321 |
| 20 | -6.7 | 52.4 | 0.361 |
| 25 | -3.9 | 58.8 | 0.405 |
| 30 | -1.1 | 65.6 | 0.452 |
| 35 | 1.7 | 72.8 | 0.502 |
| 40 | 4.4 | 80.5 | 0.555 |
| 45 | 7.2 | 88.7 | 0.612 |
| 50 | 10 | 97.4 | 0.672 |
| 55 | 12.8 | 107 | 0.738 |
| 60 | 15.6 | 116 | 0.8 |
| 65 | 18.3 | 127 | 0.876 |
| 70 | 21.1 | 138 | 0.951 |
| 75 | 23.9 | 149 | 1.027 |
| 80 | 26.7 | 161 | 1.11 |
| 85 | 29.4 | 174 | 1.2 |
| 90 | 32.2 | 187 | 1.289 |
| 95 | 35 | 201 | 1.386 |
| 100 | 37.8 | 216 | 1.489 |
| 105 | 40.6 | 232 | 1.6 |
| 110 | 43.3 | 248 | 1.71 |
| 115 | 46.1 | 265 | 1.827 |
| 120 | 48.9 | 283 | 1.951 |
| 125 | 51.7 | 301 | 2.075 |
| 130 | 54.4 | 321 | 2.213 |
| 135 | 57.2 | 341 | 2.351 |
| 140 | 60 | 363 | 2.503 |
Advantages of R502 Refrigerant
When using R502 refrigerant, you will clearly experience its core advantages, which are the key to its long-term dominance in the medium- and low-temperature refrigeration market. R502 stands out in three areas that matter to you: strong cooling performance, stable operation, and easy compatibility with most systems.
High Cooling Efficiency
R502 cools quickly and reaches below -40°C fast, making it ideal for freezers and low-temp storage. You’ll get much better performance than with R22 or R12. It offers exceptional operational stability. As an azeotropic refrigerant, its gas and liquid phases maintain consistent composition throughout the evaporation and condensation processes, with no temperature drift or phase separation issues. It ensures a stable system operating pressure and temperature.
Low Discharge Temperature
The discharge temperature of R502 compressors is 10–25°C lower than that of R22, roughly equivalent to R12. R502 keeps compressor temperatures lower, so your equipment lasts longer and runs more reliably.
Easy Compatibility
It has low requirements for system components and is compatible with air-cooled condensers, eliminating the constraints of water-cooling conditions and expanding its range of applications. It offers excellent chemical stability, is resistant to degradation, and does not corrode equipment. The system has a low failure rate, requires simple daily maintenance, and features convenient storage and charging operations that do not require special processes, thereby reducing operational and maintenance costs.
Shortcomings of R502 Refrigerant
All refrigerants have their limitations, and those of R502 are particularly pronounced. This is the primary reason it is gradually being replaced by environmentally friendly refrigerants. You must clearly understand these shortcomings to properly plan for equipment use and replacement.
Ozone Depletion
R502 harms the ozone layer and has a very high global warming potential. Because of international environmental agreements such as the Montreal Protocol, you can’t use R502 in new systems, and spare parts are harder to find. Its cost is rising, and handling it requires care due to toxic gases if overheated.
High Cost
With the tightening of environmental policies, production of R502 has long since ceased. Only recycled material remains on the market, leading to scarce supply and continuously rising prices. Procurement costs have increased significantly, making long-term use economically unfeasible. For some small refrigeration equipment manufacturers and users, using R502 refrigerant increases both equipment costs and operating expenses.
Compatibility
New generations of refrigeration equipment are no longer designed to accommodate R502, and spare parts for older units are gradually being phased out. This makes repairs difficult and costly when equipment fails. R502 decomposes toxic gases, posing safety problems at high temperatures. Furthermore, it is non-biodegradable, and leaks can cause persistent environmental pollution.
Applications of R502 Refrigerant
You’ll find R502 in supermarket freezers, ice cream machines, and refrigerated trucks. Labs, pharma, and quick-freezing lines also use it. But remember, you can only use it in older equipment.
What refrigerants can replace R502?
R502 is being phased out, so you’ll need a replacement that works well with your system and meets environmental rules.
R404A Refrigerant
R404A was an early mainstream alternative refrigerant and belongs to the HFC class of blended refrigerants. It has a 0 ODP and doesn’t deplete the ozone layer. Its cooling performance and operating pressure are very similar to those of R502, allowing for direct replacement without major equipment transformation. Fit for medium- and low-temperature commercial refrigeration and cold chain equipment, it is the preferred alternative for older R502 systems. Its GWP value is relatively high, and it is currently being gradually replaced by low-GWP refrigerants.
R507 Refrigerant
R507 is one of the long-term alternatives to R502. It is an HFC substance with an ODP value of zero and contains no ozone-depleting substances, meeting environmental requirements. Its cooling efficiency and low-temperature performance are superior to R404A, and its operating parameters are compatible with R502. You can retrofit the system easily, making it fit for industrial refrigeration and cold chain transportation equipment with high cooling efficiency requirements. It offers strong stability, simple operation, and maintenance.
R448A & R449A Refrigerant
R448A and R449A are a new generation of low-GWP refrigerants. As HFO/HFC hybrid refrigerants, they can reduce GWP values and have a low environmental impact.
Their cooling performance and operating conditions are very similar to those of R502, combining high-efficiency cooling with eco-friendly benefits. They are the main choice for replacing R502 in commercial and industrial refrigeration equipment at present, suitable for both new installations and retrofits of systems at present.
If your system still uses R502, you can switch to R507 or R448A to improve efficiency and compliance.
Final Thoughts
Knowing R502 helps you understand what options you have today. If you choose the right replacement, you can keep your systems more eco-friendly. If you still have questions about R502 refrigerant, please contact our professional team for assistance.
FAQ
Can I replace R502 with R404A without changing my equipment?
Yes. You can change R502 for R404A in the old systems. The cooling performance is similar, so major equipment changes are not needed.
How does R502 compare to R22 in cooling efficiency?
R502 is stronger. You’ll get 5–30% more cooling with the same compressor, especially in very low-temperature systems.
Why is R502 being phased out?
R502 contains CFC-115, which damages the ozone layer. International rules limit its production.
Can I retrofit my system from R502 to R507 or R448A?
Yes. These refrigerants are compatible with most R502 systems. You may check lubricants and system components for a safe retrofit.
What safety measures should you pay attention to when using R502?
You should make sure the area is ventilated. Avoid heat and sparks because R502 can decompose toxic gases if it breaks down.
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