Commercial refrigeration engineers, installers, OEMs, and cold room owners need to move toward lower-GWP refrigerants to comply with F-Gas regulations and other refrigerant regulations. Choosing the right refrigerant depends on the application, temperature range, operating conditions, system type, component compatibility, safety requirements, and whether the project is a new installation or a retrofit.
There is no one-size-fits-all refrigerant solution. No single refrigerant operates efficiently across all temperature ranges, applications, and operating conditions, so each refrigerant should be evaluated against the environment, equipment, and system requirements.
Is there a simple way to select the right refrigerant?
There is no single refrigerant that fits every commercial refrigeration application. The right refrigerant depends on system needs, refrigerant properties, operating conditions, component availability, safety requirements, cost, and long-term regulatory availability.
For new systems, refrigerant selection is usually more straightforward because the system can be designed around the chosen refrigerant. For retrofits, the process can be more complex because existing compressors, valves, oils, controls, pipework, and safety devices must be checked for compatibility.
What should be considered when choosing a refrigerant for a new system?
For new commercial refrigeration systems, refrigerant selection should consider long-term availability, component availability, cost, flammability, charge limits, safety requirements, specific capacity, pipe sizing, total system GWP, and energy efficiency.
| Consideration | Why it matters |
|---|---|
| Long- and short-term refrigerant availability | Helps ensure the refrigerant remains viable for future service and supply. |
| Component availability | Determines whether compatible compressors, valves, controls, and system components are available. |
| Cost | Affects system investment and future service costs. |
| Flammability | Determines whether additional safety requirements apply. |
| Charge limitations and safety requirements | Important for system design, installation, and compliance. |
| Specific capacity | Affects system sizing and performance. |
| Pipe sizing | Helps ensure the refrigeration system is correctly designed for the refrigerant. |
| Overall system GWP / TEWI | Helps evaluate the total environmental impact of the system. |
| Energy efficiency impact | Different components and refrigerants can affect system energy performance. |
What should be considered when retrofitting an existing system?
For retrofits, the selected refrigerant must be compared with the current refrigerant and existing system design. The most important considerations are capacity deviation, compressor and oil compatibility, component compatibility, flammability, discharge temperature, glide, superheat settings, safety device settings, and pipe sizing.
| Retrofit consideration | Why it matters |
|---|---|
| Long- and short-term refrigerant availability | Helps ensure future serviceability and supply. |
| Capacity deviation from the current refrigerant | Shows whether the replacement refrigerant can meet the required cooling demand. |
| Compressor, oil, and component compatibility | Determines whether existing equipment can continue to be used. |
| Flammability class | Higher flammability classes may introduce additional safety requirements. |
| Discharge temperature | Must remain within safe operating limits. |
| Glide | High-glide refrigerants may require additional attention during selection and setup. |
| Superheat setting | Expansion valves may require adjustment for correct operation. |
| Safety device settings | Pressure switches and safety devices may need adjustment for the new refrigerant. |
| Pipe sizing | Existing piping must be suitable for the replacement refrigerant and system operation. |
Which refrigerants can replace R404A and R507?
Lower-GWP alternatives for R404A and R507 include A1, A2L, and A3 refrigerants. R448A, R449A, R407H, and R452A are A1 non-flammable alternatives; R454A, R454C, and R455A are A2L mildly flammable alternatives with GWP below 150; and R290 propane and R600a isobutane are A3 highly flammable alternatives.
| Existing refrigerant | Alternative refrigerants | Safety class / note |
|---|---|---|
| R404A / R507 | R448A, R449A, R407H, R452A | A1, non-flammable |
| R404A / R507 | R454A, R454C, R455A | A2L, mildly flammable, GWP below 150 |
| R404A / R507 | R290 propane, R600a isobutane | A3, highly flammable |
| R404A / R507 | R744 CO₂ | Alternative option, but requires different system design because it operates at considerably higher pressure |
Which refrigerants can replace R134a?
Lower-GWP alternatives for R134a include A1, A2L, and A3 refrigerants. R513A, R450A, and R513B are A1 non-flammable alternatives; R516A and R445A are A2L mildly flammable alternatives with GWP below 150; and R290 propane and R600a isobutane are A3 highly flammable alternatives.
| Existing refrigerant | Alternative refrigerants | Safety class / note |
|---|---|---|
| R134a | R513A, R450A, R513B | A1, non-flammable |
| R134a | R516A, R445A | A2L, mildly flammable, GWP below 150 |
| R134a | R290 propane, R600a isobutane | A3, highly flammable |
| R134a | R744 CO₂ | Alternative option, but requires different system design because it operates at considerably higher pressure |
Can CO₂ replace R404A, R507, or R134a?
R744, also known as CO₂, is an alternative for R404A, R507, and R134a. However, CO₂ operates at considerably higher pressure, so it requires a different system design and should not be treated as a like-for-like drop-in replacement.
Can existing R404A or R507 systems be retrofitted with A2L or A3 refrigerants?
Existing R404A and R507 systems should be retrofitted with A1 refrigerants only. A2L and A3 refrigerants are for new installations.
Using lower-GWP A1 refrigerants to retrofit R404A, R507, and R134a systems avoids the need to check flammable refrigerant requirements. If the new refrigerant has a higher flammability class, charge limits and safety requirements must be checked in applicable standards and regulations.
What should be checked before retrofitting an old system?
When retrofitting an existing commercial refrigeration system, compare the new refrigerant with the current refrigerant and check whether the existing system can operate safely and efficiently with the replacement.
Before retrofitting, check:
- how close the new refrigerant is to the current refrigerant’s pressure and capacity
- whether the refrigerant is A1, A2L, or A3
- charge limits and safety requirements if the refrigerant has a higher flammability class
- refrigerant charge limits in EN 378-1:2016 table C2 and application-specific standards in the IEC 60335-2-xx series
- whether auxiliary electrical equipment could become an ignition source when using a flammable refrigerant in a new system
- whether the refrigerant has high glide
- whether the old refrigerant has been recovered and kept separate from other refrigerants
Will a new refrigerant force me to use new components?
A new refrigerant does not always require a completely new set of components. In some cases, the same compressors, heat exchangers, valves, and controls can continue to be used, but components must always be checked to confirm whether they need modification or replacement before they are ready for the new refrigerant.
Component checklist for refrigerant transition
| Component or setting | What to check |
|---|---|
| Compressor and oil | Check compressor approval and oil compatibility for the new refrigerant. If not compatible, replace with a compatible compressor. |
| Components with gaskets | Check gasket compatibility with the new refrigerant and oils. |
| Thermostatic expansion valves | Check whether adjustment is enough or whether a new valve version is needed. A compatible bulb charge may be required for good superheat control. |
| Electronic expansion valve controllers | Check whether new refrigerant-specific parameters are required. Set the new refrigerant in the superheat controller. If the refrigerant is not listed, use user-defined parameters. |
| Pressure switches and control devices | Adjust control devices to match the new refrigerant pressures. |
What should be checked for expansion valves and controllers?
Thermostatic expansion valves may need adjustment or replacement when changing refrigerant. A new valve version may be needed if the bulb charge must be compatible with the new refrigerant to allow good superheat control.
Electronic expansion valve controllers may need new refrigerant-specific parameters. The new refrigerant should be set in the superheat controller for the electric expansion valve. If the refrigerant is not listed, user-defined parameters can be entered. Danfoss controllers already include many lower-GWP refrigerants.
Where can I learn more about low-GWP refrigerants?
Danfoss provides resources to help cold room operators, installers, OEMs, and refrigeration professionals select low-GWP refrigerants. The guide points users to the low-GWP refrigerant resource library at Refrigerant center and component selection at Coolselector.
Low-GWP refrigerant selection summary
| Question | Short answer |
|---|---|
| Is there one best refrigerant for all systems? | No. No single refrigerant operates efficiently across all temperature ranges, applications, and operating conditions. |
| Is refrigerant selection easier for new systems or retrofits? | New systems are usually more straightforward; retrofits are more complex because existing components must be checked. |
| Which refrigerants can replace R404A and R507? | Options include A1 refrigerants such as R448A, R449A, R407H, and R452A; A2L refrigerants such as R454A, R454C, and R455A; A3 refrigerants such as R290 and R600a; and CO₂ with different system design. |
| Which refrigerants can replace R134a? | Options include A1 refrigerants such as R513A, R450A, and R513B; A2L refrigerants such as R516A and R445A; A3 refrigerants such as R290 and R600a; and CO₂ with different system design. |
| Can A2L and A3 refrigerants be used for existing R404A/R507 retrofits? | Existing R404A/R507 systems should be retrofitted with A1 refrigerants only. A2L and A3 refrigerants are for new installations. |
| Does a new refrigerant always require new components? | Not always. Some existing compressors, heat exchangers, valves, and controls can be reused, but compatibility must be checked. |
FAQ
How do I choose the right low-GWP refrigerant?
- Choose a low-GWP refrigerant by matching refrigerant properties to the application, operating conditions, temperature range, component availability, safety requirements, system cost, pipe sizing, TEWI, and energy efficiency needs.
Is there a one-size-fits-all low-GWP refrigerant?
- No. There is no one-size-fits-all solution because no single refrigerant operates efficiently across all temperature ranges, applications, and operating conditions.
What refrigerants should I consider instead of R404A or R507?
- Options include R448A, R449A, R407H, R452A, R454A, R454C, R455A, R290, R600a, and R744 CO₂, depending on system type and application.
What refrigerants should I consider instead of R134a?
- Options include R513A, R450A, R513B, R516A, R445A, R290, R600a, and R744 CO₂, depending on system type and application.
Can I retrofit an existing R404A or R507 system with A2L refrigerants?
- Existing R404A and R507 systems should be retrofitted with A1 refrigerants only. A2L and A3 refrigerants are for new installations.
Does CO₂ require a different system design?
- Yes. R744 CO₂ is an alternative for R404A, R507, and R134a, but it operates at considerably higher pressure and requires a different system design.
Will I need new components when changing refrigerant?
- Not always. In some cases, existing compressors, heat exchangers, valves, and controls can be used, but they must be checked for compatibility and may need adjustment, modification, or replacement.
How do I retrofit a walk-in cooler from R404A to a low-GWP refrigerant?
- Replace seals, check oil compatibility, adjust expansion valve, and recharge with approved low-GWP refrigerant. Check to make sure that super heat adjustment alone will be sufficient to adjust for the changes. If not, a dedicated TXV for that refrigerant will be necessary.
What should I check on thermostatic expansion valves?
- Thermostatic expansion valves may need adjustment or replacement, especially if a compatible bulb charge is needed to provide good superheat control with the new refrigerant.
What should I check on electronic expansion valve controllers?
- Electronic expansion valve controllers may require refrigerant-specific parameters. The new refrigerant should be set in the superheat controller, and if it is not listed, user-defined parameters can be entered.
My walk-in cooler is 15 years old. Should I upgrade the components or replace the whole thing — and do refrigerant phase-out rules force my hand?
- Replace if insulation, compressor, or panels are degraded; upgrade if only controls or fans need improvement.
What refrigerant strategy should a supermarket chain adopt as R404A is phased out?
- Transition to low-GWP refrigerants like CO₂ or A2L blends, considering retrofit feasibility.
What are A2L refrigerants and why is the industry switching to them?
- A2L refrigerants are mildly flammable, low-GWP alternatives to HFCs, meeting regulatory phase-down goals.
Where can I find Danfoss refrigerant and component selection resources?
- Danfoss refrigerant resources are available at Refrigerant center, and component selection support is available at Coolselector.
Downloads
This page summarizes the key decision points from the Danfoss low-GWP refrigerant FAQ. Download the full PDF for the original article, refrigerant lists, retrofit considerations, component checklist, and supporting guidance.