Regardless whether you’re cooling batteries on an electric bus, managing HVAC in a mining truck, or controlling temperatures in a battery energy storage system, refrigerants and F-gases sit at the heart of every modern thermal management system.
For engineers working in bus and coach, off-highway, special vehicle and stationary power applications, the latest F-gas regulations are changing how systems are specified, designed, tested and maintained. The rules don’t just affect which refrigerant you select; they also have implications for component choice, system architecture, total charge, service strategies and long-term platform roadmaps.
In this thermal academy article, we’ll look at:
- The key EU and UK regulations that apply to heavy vehicles and stationary power
- The key EU and UK regulations that apply to heavy vehicles and stationary power
- How these rules intersect with wider emissions legislation
1. What Are F-gases and Why Do They Matter for Thermal Management
If you’re reading this, you may already know the significance of a fluorinated gas (F-gas), but in case you don’t, here’s a quick refresher.
F-gases are a group of man-made greenhouse gases widely used in refrigeration, air conditioning, heat pumps, and thermal management systems. They are effective refrigerants because of their stability and thermodynamic properties, but they also have a high Global Warming Potential (GWP) – sometimes referred to in the context of Total Equivalent Warming Impact (TEWI).
In practical terms, many F-gases have a significantly higher GWP than carbon dioxide (Figure 1 demonstrates the GWP of main refrigerants), meaning that even small amounts leaking from a system can have a major environmental impact.
| Refrigerant | GWP | Category |
|---|---|---|
|
HFC-R404A |
3922 |
Very high > 2500 |
|
HFC-R410A |
2088 |
High-700-2500 |
|
HFC-R407C |
1774 |
High – 700-2500 |
|
HFC-R134a |
1430 |
High 700-2500 |
|
HFC-R32 |
675 |
Medium 150-700 |
|
HFC/HFO-R513A |
631 |
Medium 150-700 |
|
HFC-R454C (3) |
148 |
Low < 150 |
|
HFO-R1234ze |
7(1), 1(2) |
Low < 150 |
|
HFO-R1234yf |
4(1), 0(2) |
Low < 150 |
|
R290 (Propane) |
3 |
Low < 150 |
|
R744 (CO2) |
1 |
Low < 150 |
|
R717 (NH3) |
0 . |
Low < 150 |
Because of their impact, F-gases have become a major focus in climate legislation in the EU, USA and UK. F-gas regulations are designed to phase down their use, reduce leakage and accelerate the adoption of lower-GWP alternatives, helping to support net-zero targets.
For engineers and OEMs, this makes refrigerant selection, system design and long-term compliance critical considerations in both new and retrofit thermal management projects across vehicles and stationary power systems.
Figure 1: GWP of main refrigerants (4th IPCC report)
(1) 2010 SAP report (Scientific Assessment Panel),
(2) 5th IPCC report (Intergovernmental Panel on Climate Change)
(3) Has been added into the table, not part of IPCC report. From https://nationalref.com/products/r454c/.
We’ll now explore what the latest regulations actually say – and what that means in practice.
Understanding Regulations and Standards in the Industry
Where F-Gases are concerned, the transport, industrial machinery and stationary power industries must adhere to strict regulations intended to reduce overall emissions. To comply with these required standards, both manufacturers and operators must adopt appropriate cooling architectures, use specific refrigerants and follow defined procedures for handling, leak checking and service.
EU Regulations and Laws
In alignment with the European Climate Law, the European Commission proposed a new F-gas Regulation, leading to the adoption of Regulation (EU) 2024/573 on 7 February 2024, which became effective on 11 March 2024.
This updated regulation:
- Introduces stricter measures to reduce hydrofluorocarbons (HFCs)
- Aims for a complete phase-out of HFCs in the EU by 2050
- Extends coverage to more equipment and gases
- Enforces measures to prevent leakage during transportation, installation, servicing and disposal
From 2025, EU production of HFCs will be capped, with producers receiving rights equivalent to 60% of their average annual production from 2011 to 2013, reducing to 15% by 2036. This effectively tightens supply and pushes the market toward low-GWP and natural refrigerants.
Another important piece of legislation is the EU 517 / 2014 regulation, as amended in 2022, which was established to check for leaks. Under Article 4.4, operators are obligated to repair leakage without undue delay, and the frequency of leak checks is based on the refrigerant charge in tonnes of CO₂ equivalent per circuit.
When a leakage detection system is installed:
- The required inspection frequency is halved
- The system must alert the operator and itself be checked at least once a year
| Leakage Detection | Periodically Check | ||||
|---|---|---|---|---|---|
|
System WITHOUT Leakage Detection |
No Check |
Every 12 months |
Every 6 months |
Not Allowed |
|
|
System WITH Leakage Detection |
No Check |
Every 24 months |
Every 12 months |
Every 6 months |
|
|
Refrigerant Charge per Circuit (CO2 equivalent) |
< 5 ton |
5 ≤ Charge < 50 ton |
50 ≤ Charge < 500 ton |
Charge > 500 ton |
|
|
Refrigerant Charge per Circuit (kg) |
R134a (GWP 1430) |
Charge < 3.5 kg |
3.5 ≤ Charge < 34.9 kg |
34.9 ≤ Charge < 349.7 kg |
Charge > 349.7 kg |
|
R407c (GWP 1774) |
Charge < 2.8 kg |
2.8 ≤ Charge < 28.2 kg |
28.2 ≤ Charge < 281.9 kg |
Charge > 281.9 kg |
|
|
R410A (GWP 2088) |
Charge < 2.4 kg |
2.4 ≤ Charge < 23.9 kg |
23.9 ≤ Charge < 239.5 kg |
Charge > 239.5 kg |
|
|
R32 (GWP 675) |
Charge < 7.4 kg |
7.4 ≤ Charge < 74.1 kg |
74.1 ≤ Charge < 740.7 kg |
Charge >740.7 kg |
|
|
HFO R1234ze |
Charge < 2.0 kg |
2.0 ≤ Charge < 10.0 kg |
10.0 ≤ Charge < 100.0 kg |
Charge > 100.0 kg |
|
Figure 2: EU 517 / 2014 amendment 2022 F-gas Regulation – Leak Checks (“ton” means tonnes of CO₂ equivalent (t CO₂-eq), not metric tons of refrigerant)
For full details on regulations and laws in the UK, refer to the official GOV.UK guidance on F-gases and HCFCs.
Euro VI and how it connects to F-gas legislation
Euro VI is a strict EU regulation aimed at reducing harmful emissions from heavy-duty vehicles like trucks and buses. It focuses on exhaust emissions – NOₓ, CO, hydrocarbons and particulate matter – rather than refrigerants themselves.
However, Euro VI sits alongside F-gas legislation as part of a broader environmental push. The drive to lower overall emissions and improve vehicle efficiency under Euro VI has encouraged OEMs and suppliers to scrutinise every source of greenhouse gas emissions, including those from thermal management systems.
Although Euro VI doesn’t set specific limits for refrigerant emissions, it works in combination with F-gas rules to encourage:
- Lower-GWP refrigerant selection
- Improved system efficiency
- Reduced leakage and better maintenance practices.
In a future Grayson Thermal Academy article, we’ll explore the upcoming Euro 7 emissions standards, the changes they bring and what they mean for thermal system design. You can sign up to The Thermal Exchange newsletter to be notified when it’s published. Sign up to our newsletter here to ensure you’re in the know.
The Combined Impact on Thermal Management:
As emissions limits become tighter, attention increasingly turns to auxiliary systems such as:
- HVAC for driver and passenger comfort
- Battery cooling and power electronics cooling
- Thermal management for hybrid and electric drivetrains
In electric and hybrid vehicles especially, thermal management affects both range and performance. Moving away from high-GWP refrigerants and into better-optimised systems is now part of the broader emissions-reduction strategy.
Designing F-Gas Compliant Thermal Management Systems
Switching to alternative refrigerants is not just a case of swapping one gas for another. Engineers must reassess system design, components and controls under new operating conditions – while keeping an eye on cost, logistics and long-term serviceability.
System Efficiency and Component Compatibility
Refrigerants like R1234yf require carefully managed operating pressures and temperatures to maintain efficiency and avoid unnecessary system strain. Refrigerant-specific heat exchangers and system architectures are vital to maximise heat transfer without compromising safety or durability.
For example, Grayson’s CM-series CTMS has been developed to offer optimised performance compatible with next-generation refrigerants, supporting stable thermal control for high-voltage applications of up to 850 V. Our CTMS range can be configured for both vehicle and stationary power applications, providing centralised management of multiple thermal loops.
Future-proofing designs with flexible refrigerant options
Grayson’s product portfolio is engineered with future refrigerant transitions in mind. Products such as:
- CTMS – complete thermal management systems
- M1 BTMS – battery thermal management
- CA-Series Cabin HVAC – driver climate
are designed so that they can be adapted for different refrigerants and thermal duties, whether managing battery packs, power electronics or passenger cabins.
By integrating these systems, OEMs can meet evolving regulatory requirements, retain flexibility for future refrigerant changes or upgrades, and reduce the risk of costly redesigns later in the platform lifecycle.
This future-ready approach helps de-risk system development and prolongs the operational relevance of OEM platforms.
Grayson CTMS RM-Series
Engineering Considerations for Switching to Alternative Refrigerants
Transitioning to new refrigerants demands a system-wide engineering review. Aspects for engineers to evaluate include:
- Material compatibility
- Seal integrity
- Lubricant selection
- Pressure rating
- Thermodynamic properties
Approaches to lower system refrigerant requirements, such as heat exchangers and secondary coolant loops (indirect condensing), are increasingly used to minimise environmental risk and improve serviceability.
If you’d like a refresher on this topic, we cover the differences and use cases of direct and indirect condensing in a separate Grayson Thermal Academy blog.
Additionally, incorporating smart control strategies for refrigerant management, temperature balancing, and fault detection enhances system reliability. Grayson’s expertise in integrated thermal systems, combined with the capability to adapt to future regulations and industry standards, enables OEMs to navigate these transitions efficiently while delivering high-performance, compliant systems.
Adopting Proactive Measures to Anticipate Regulatory Changes
Responding to regulations only when they come into force can leave engineering programmes scrambling. A more effective approach is to monitor regulatory trends and technology developments proactively.
This often includes:
- Investing in R&D to validate new refrigerants and system architectures ahead of time
- Assessing how proposed changes may impact current and future platforms
- Building flexibility into system designs so you can pivot without major rework
By taking this proactive approach, OEMs can implement design changes before new emissions or F-gas requirements are mandatory, allocate resources more effectively and avoid last-minute redesigns. In addition, companies reduce the risk of programme delays, rushed engineering changes and unexpected field issues.
In short, a proactive stance can turn compliance from a constraint into a competitive advantage for forward-thinking OEMs.
The Role of Data in Enhancing Compliance and Operational Efficiency
Telematics systems and data analytics also play an important role in monitoring compliance in real time, as well as allowing businesses to track operational efficiency and ensure adherence to safety protocols.
Armed with this data, companies can monitor parameters like vehicle emissions in real time, and use systems to obtain actionable insights which help to optimise their fuel usage, reduce overall costs and ensure vehicles are operating safely.
For fleets and stationary power operators, this means they can:
- Monitor factors such as energy consumption, cooling performance and system alarms
- Use the insights to optimise fuel or energy use, reduce costs and maintain uptime
- Demonstrate compliance with internal and external standards
Grayson’s products, including the CM-series and RM-series CTMS ranges, use CAN communication to share detailed system information with vehicle and fleet systems. As data becomes increasingly integral to vehicle and stationary power operations, leveraging these insights will be key to improving both compliance and operational effectiveness.
Common Alternative Refrigerants and Next-Generation Solutions
As the industry phases down high-GWP F-gases, alternative refrigerants are becoming increasingly central to new system designs.
Low-GWP and Natural Refrigerant Options
Options such as R-454C are gaining traction because they offer significantly lower GWP (R454C has a GWP of 148), while still delivering good performance. However, each alternative comes with its own handling, design and safety requirements that must be considered when specifying components and system layouts.
The table below shows what we are replacing current refrigerants (R134a and R407C) with and provides a comparison table of the characteristics when we want to achieve 10kW cooling capacity at 50°C ambient:
| Current | Next Generation | |||||||
|---|---|---|---|---|---|---|---|---|
|
|
Unit |
R134a |
R513A |
R1234yf |
R407C |
R454C |
R290 |
CO2 |
|
Condensing Temperature |
℃ |
50 |
50 |
50 |
50 |
50 |
50 |
30 |
|
Condensing Pressure |
bar |
13.18 |
13.77 |
13.02 |
19.88 |
18.7 |
17.13 |
71.2 |
|
Power Input |
kW |
2.73 |
2.37 |
2.22 |
2.86 |
2.6 |
2.71 |
6.21 |
|
COP |
– |
5.22 |
5.15 |
-0.64 |
5.17 |
4.98 |
6.77 |
16.7 |
|
Requested Cooling Capacity |
kW |
10 |
10 |
10 |
10 |
10 |
10 |
10 |
|
Mass flow |
kg/h |
342 |
342 |
342 |
342 |
342 |
342 |
342 |
|
GWP |
– |
1430 |
573 |
< 1 |
1774 |
150 |
3 |
1 |
|
Safety Group |
– |
A1 |
A1 |
A2L |
A1 |
A2L |
A3 |
A1 |
Figure 3: Replacements of current refrigerants
Trade-Offs in Efficiency, Cost and Safety
While low-GWP refrigerants deliver environmental benefits, they can introduce new design trade offs:
- Natural refrigerants like CO₂ require higher operating pressures, demanding more robust components and controls.
- Hydrocarbons are efficient and cost-effective but introduce flammability risks, which means enhanced safety mechanisms and careful enclosure management.
- Engineers must also account for characteristics like refrigerant glide. This is the temperature range over which a refrigerant blend evaporates or condenses at constant pressure. It occurs in zeotropic blends (like R-407C) because their components have different boiling points, causing phase change over a range of temperatures rather than at a single point (see figure 5).
- Pure refrigerants and azeotropic blends have little or no glide (see figure 4). This affects heat exchanger design, system efficiency, and maintenance.
Other considerations must also be taken into account, like thermodynamic properties and compatibility with existing infrastructure, balancing upfront cost, operational safety and long-term system efficiency.
What’s Next for the Industry?
The future of refrigeration lies in systems designed around ultra-low-GWP refrigerants, intelligent controls, and modular thermal management.
As the electrification of vehicles and machinery accelerates, thermal systems will need to manage both refrigerant-based cooling and battery/electronics thermal loads in one integrated platform.
With this in mind, you should expect to see further development in:
- Sealed system designs
- New heat pump applications
- Thermal loops optimised around specific refrigerants and use cases
OEMs that partner with experienced thermal management specialists will be better placed to adapt to these rapid changes, while still meeting performance, reliability and regulatory requirements.
What This Means for Your Next Thermal Management Project
F-gas regulations are reshaping the way thermal systems are specified and designed across bus and coach, off-highway, special vehicle, and stationary power applications. They touch everything from refrigerant selection to system architecture, testing, serviceability, and even the digital data that underpins compliance monitoring.
For OEMs and engineers, that means looking beyond immediate project needs and designing with the future in mind, from understanding how refrigerant GWP, charge limits and leak-checking requirements, to new phase-down schedules could affect your platforms over their lifetime.
For decades, our team of thermal management and F-gas specialists has worked directly with design, systems, and validation engineers to help navigate these complexities. We combine over forty years of experience in refrigerant-based cooling, battery and power electronics thermal control, and climate systems for heavy vehicles, with up-to-date understanding of the latest F-gas regulations, standards, and technologies.
Whether you’re developing a new platform or adapting existing systems for upcoming changes, we can help you:
- Identify the most suitable refrigerants and architectures for your application
- Balance performance, compliance, and serviceability
- Integrate flexible, future-proof designs that keep pace with evolving legislation
Our team of thermal experts are here to make sure you stay compliant and stay ahead.
If you’re reviewing refrigerant options or planning your next generation of thermal systems, speak to our team today. We’ll help you turn regulatory challenges into smarter, more efficient, and future-ready designs.
Related Articles
Regardless whether you’re cooling batteries on an electric bus, managing HVAC in a mining truck, or controlling temperatures in a battery energy storage system, refrigerants and F-gases sit at the heart of every modern thermal management system.
For engineers working in bus and coach, off-highway, special vehicle and stationary power applications, the latest F-gas regulations are changing how systems are specified, designed, tested and maintained. The rules don’t just affect which refrigerant you select; they also have implications for component choice, system architecture, total charge, service strategies and long-term platform roadmaps.
In this thermal academy article, we’ll look at:
• What F-gases are and why they have become a regulatory focus
• The key EU and UK regulations that apply to heavy vehicles and stationary power
• How these rules intersect with wider emissions legislation
• What this means for refrigerant choice and thermal system design
• How OEMs can build more future-ready, F-gas-compliant systems
1. What Are F-gases and Why Do They Matter for Thermal Management
If you’re reading this, you may already know the significance of a fluorinated gas (F-gas), but in case you don’t, here’s a quick refresher.
F-gases are a group of man-made greenhouse gases widely used in refrigeration, air conditioning, heat pumps, and thermal management systems. They are effective refrigerants because of their stability and thermodynamic properties, but they also have a high Global Warming Potential (GWP) – sometimes referred to in the context of Total Equivalent Warming Impact (TEWI).
In practical terms, many F-gases have a significantly higher GWP than carbon dioxide (Figure 1 demonstrates the GWP of main refrigerants), meaning that even small amounts leaking from a system can have a major environmental impact.
| Refrigerant | GWP | Category |
|---|---|---|
|
HFC-R404A |
3922 |
Very high > 2500 |
|
HFC-R410A |
2088 |
High-700-2500 |
|
HFC-R407C |
1774 |
High – 700-2500 |
|
HFC-R134a |
1430 |
High 700-2500 |
|
HFC-R32 |
675 |
Medium 150-700 |
|
HFC/HFO-R513A |
631 |
Medium 150-700 |
|
HFC-R454C (3) |
148 |
Low < 150 |
|
HFO-R1234ze |
7(1), 1(2) |
Low < 150 |
|
HFO-R1234yf |
4(1), 0(2) |
Low < 150 |
|
R290 (Propane) |
3 |
Low < 150 |
|
R744 (CO2) |
1 |
Low < 150 |
|
R717 (NH3) |
0 . |
Low < 150 |
Because of their impact, F-gases have become a major focus in climate legislation in the EU, USA and UK. F-gas regulations are designed to phase down their use, reduce leakage and accelerate the adoption of lower-GWP alternatives, helping to support net-zero targets.
For engineers and OEMs, this makes refrigerant selection, system design and long-term compliance critical considerations in both new and retrofit thermal management projects across vehicles and stationary power systems.
Figure 1: GWP of main refrigerants (4th IPCC report)
(1) 2010 SAP report (Scientific Assessment Panel),
(2) 5th IPCC report (Intergovernmental Panel on Climate Change)
(3) Has been added into the table, not part of IPCC report. From https://nationalref.com/products/r454c/.
We’ll now explore what the latest regulations actually say – and what that means in practice.
Understanding Regulations and Standards in the Industry
Where F-Gases are concerned, the transport, industrial machinery and stationary power industries must adhere to strict regulations intended to reduce overall emissions. To comply with these required standards, both manufacturers and operators must adopt appropriate cooling architectures, use specific refrigerants and follow defined procedures for handling, leak checking and service.
EU Regulations and Laws
In alignment with the European Climate Law, the European Commission proposed a new F-gas Regulation, leading to the adoption of Regulation (EU) 2024/573 on 7 February 2024, which became effective on 11 March 2024.
This updated regulation:
• Introduces stricter measures to reduce hydrofluorocarbons (HFCs)
• Aims for a complete phase-out of HFCs in the EU by 2050
• Extends coverage to more equipment and gases
• Enforces measures to prevent leakage during transportation, installation, servicing and disposal
From 2025, EU production of HFCs will be capped, with producers receiving rights equivalent to 60% of their average annual production from 2011 to 2013, reducing to 15% by 2036. This effectively tightens supply and pushes the market toward low-GWP and natural refrigerants.
Another important piece of legislation is the EU 517 / 2014 regulation, as amended in 2022, which was established to check for leaks. Under Article 4.4, operators are obligated to repair leakage without undue delay, and the frequency of leak checks is based on the refrigerant charge in tonnes of CO₂ equivalent per circuit.
When a leakage detection system is installed:
• The required inspection frequency is halved, a
• The system must alert the operator and itself be checked at least once a year
| Leakage Detection | Periodically Check | ||||
|---|---|---|---|---|---|
|
System WITHOUT Leakage Detection |
No Check |
Every 12 months |
Every 6 months |
Not Allowed |
|
|
System WITH Leakage Detection |
No Check |
Every 24 months |
Every 12 months |
Every 6 months |
|
|
Refrigerant Charge per Circuit (CO2 equivalent) |
< 5 ton |
5 ≤ Charge < 50 ton |
50 ≤ Charge < 500 ton |
Charge > 500 ton |
|
|
Refrigerant Charge per Circuit (kg) |
R134a (GWP 1430) |
Charge < 3.5 kg |
3.5 ≤ Charge < 34.9 kg |
34.9 ≤ Charge < 349.7 kg |
Charge > 349.7 kg |
|
R407c (GWP 1774) |
Charge < 2.8 kg |
2.8 ≤ Charge < 28.2 kg |
28.2 ≤ Charge < 281.9 kg |
Charge > 281.9 kg |
|
|
R410A (GWP 2088) |
Charge < 2.4 kg |
2.4 ≤ Charge < 23.9 kg |
23.9 ≤ Charge < 239.5 kg |
Charge > 239.5 kg |
|
|
R32 (GWP 675) |
Charge < 7.4 kg |
7.4 ≤ Charge < 74.1 kg |
74.1 ≤ Charge < 740.7 kg |
Charge >740.7 kg |
|
|
HFO R1234ze |
Charge < 2.0 kg |
2.0 ≤ Charge < 10.0 kg |
10.0 ≤ Charge < 100.0 kg |
Charge > 100.0 kg |
|
Figure 2: EU 517 / 2014 amendment 2022 F-gas Regulation – Leak Checks (“ton” means tonnes of CO₂ equivalent (t CO₂-eq), not metric tons of refrigerant)
For full details on regulations and laws in the UK, refer to the official GOV.UK guidance on F-gases and HCFCs.
Euro VI and how it connects to F-gas legislation
Euro VI is a strict EU regulation aimed at reducing harmful emissions from heavy-duty vehicles like trucks and buses. It focuses on exhaust emissions – NOₓ, CO, hydrocarbons and particulate matter – rather than refrigerants themselves.
However, Euro VI sits alongside F-gas legislation as part of a broader environmental push. The drive to lower overall emissions and improve vehicle efficiency under Euro VI has encouraged OEMs and suppliers to scrutinise every source of greenhouse gas emissions, including those from thermal management systems.
Although Euro VI doesn’t set specific limits for refrigerant emissions, it works in combination with F-gas rules to encourage:
• Lower-GWP refrigerant selection
• Improved system efficiency
• Reduced leakage and better maintenance practices.
In a future Grayson Thermal Academy article, we’ll explore the upcoming Euro 7 emissions standards, the changes they bring and what they mean for thermal system design. You can sign up to The Thermal Exchange newsletter to be notified when it’s published. Sign up to our newsletter here to ensure you’re in the know.
The Combined Impact on Thermal Management:
As emissions limits become tighter, attention increasingly turns to auxiliary systems such as:
• HVAC for driver and passenger comfort
• Battery cooling and power electronics cooling
• Thermal management for hybrid and electric drivetrains
In electric and hybrid vehicles especially, thermal management affects both range and performance. Moving away from high-GWP refrigerants and into better-optimised systems is now part of the broader emissions-reduction strategy.
Designing F-Gas Compliant Thermal Management Systems
Switching to alternative refrigerants is not just a case of swapping one gas for another. Engineers must reassess system design, components and controls under new operating conditions – while keeping an eye on cost, logistics and long-term serviceability.
System Efficiency and Component Compatibility
Refrigerants like R1234yf require carefully managed operating pressures and temperatures to maintain efficiency and avoid unnecessary system strain. Refrigerant-specific heat exchangers and system architectures are vital to maximise heat transfer without compromising safety or durability.
For example, Grayson’s CM-series CTMS has been developed to offer optimised performance compatible with next-generation refrigerants, supporting stable thermal control for high-voltage applications of up to 850 V. Our CTMS range can be configured for both vehicle and stationary power applications, providing centralised management of multiple thermal loops.
Future-proofing designs with flexible refrigerant options
Grayson’s product portfolio is engineered with future refrigerant transitions in mind. Products such as:
• CTMS – complete thermal management systems
• M1 BTMS – battery thermal management
• CA-Series Cabin HVAC – driver climate
are designed so that they can be adapted for different refrigerants and thermal duties, whether managing battery packs, power electronics or passenger cabins.
By integrating these systems, OEMs can meet evolving regulatory requirements, retain flexibility for future refrigerant changes or upgrades, and reduce the risk of costly redesigns later in the platform lifecycle.
This future-ready approach helps de-risk system development and prolongs the operational relevance of OEM platforms.
Grayson CTMS RM-Series
Engineering Considerations for Switching to Alternative Refrigerants
Transitioning to new refrigerants demands a system-wide engineering review. Aspects for engineers to evaluate include:
• Material compatibility
• Seal integrity
• Lubricant selection
• Pressure rating
• Thermodynamic properties
Approaches to lower system refrigerant requirements, such as heat exchangers and secondary coolant loops (indirect condensing), are increasingly used to minimise environmental risk and improve serviceability.
If you’d like a refresher on this topic, we cover the differences and use cases of direct and indirect condensing in a separate Grayson Thermal Academy blog.
Additionally, incorporating smart control strategies for refrigerant management, temperature balancing, and fault detection enhances system reliability. Grayson’s expertise in integrated thermal systems, combined with the capability to adapt to future regulations and industry standards, enables OEMs to navigate these transitions efficiently while delivering high-performance, compliant systems.
Adopting Proactive Measures to Anticipate Regulatory Changes
Responding to regulations only when they come into force can leave engineering programmes scrambling. A more effective approach is to monitor regulatory trends and technology developments proactively.
This often includes:
• Investing in R&D to validate new refrigerants and system architectures ahead of time
• Assessing how proposed changes may impact current and future platforms
• Building flexibility into system designs so you can pivot without major rework
By taking this proactive approach, OEMs can implement design changes before new emissions or F-gas requirements are mandatory, allocate resources more effectively and avoid last-minute redesigns. In addition, companies reduce the risk of programme delays, rushed engineering changes and unexpected field issues.
In short, a proactive stance can turn compliance from a constraint into a competitive advantage for forward-thinking OEMs.
The Role of Data in Enhancing Compliance and Operational Efficiency
Telematics systems and data analytics also play an important role in monitoring compliance in real time, as well as allowing businesses to track operational efficiency and ensure adherence to safety protocols.
Armed with this data, companies can monitor parameters like vehicle emissions in real time, and use systems to obtain actionable insights which help to optimise their fuel usage, reduce overall costs and ensure vehicles are operating safely.
For fleets and stationary power operators, this means they can:
• Monitor factors such as energy consumption, cooling performance and system alarms
• Use the insights to optimise fuel or energy use, reduce costs and maintain uptime
• Demonstrate compliance with internal and external standards
Grayson’s products, including the CM-series and RM-series CTMS ranges, use CAN communication to share detailed system information with vehicle and fleet systems. As data becomes increasingly integral to vehicle and stationary power operations, leveraging these insights will be key to improving both compliance and operational effectiveness.
Common Alternative Refrigerants and Next-Generation Solutions
As the industry phases down high-GWP F-gases, alternative refrigerants are becoming increasingly central to new system designs.
Low-GWP and Natural Refrigerant Options
Options such as R-454C are gaining traction because they offer significantly lower GWP (R454C has a GWP of 148), while still delivering good performance. However, each alternative comes with its own handling, design and safety requirements that must be considered when specifying components and system layouts.
The table below shows what we are replacing current refrigerants (R134a and R407C) with and provides a comparison table of the characteristics when we want to achieve 10kW cooling capacity at 50°C ambient:
| Current | Next Generation | |||||||
|---|---|---|---|---|---|---|---|---|
|
|
Unit |
R134a |
R513A |
R1234yf |
R407C |
R454C |
R290 |
CO2 |
|
Condensing Temperature |
℃ |
50 |
50 |
50 |
50 |
50 |
50 |
30 |
|
Condensing Pressure |
bar |
13.18 |
13.77 |
13.02 |
19.88 |
18.7 |
17.13 |
71.2 |
|
Power Input |
kW |
2.73 |
2.37 |
2.22 |
2.86 |
2.6 |
2.71 |
6.21 |
|
COP |
– |
5.22 |
5.15 |
-0.64 |
5.17 |
4.98 |
6.77 |
16.7 |
|
Requested Cooling Capacity |
kW |
10 |
10 |
10 |
10 |
10 |
10 |
10 |
|
Mass flow |
kg/h |
342 |
342 |
342 |
342 |
342 |
342 |
342 |
|
GWP |
– |
1430 |
573 |
< 1 |
1774 |
150 |
3 |
1 |
|
Safety Group |
– |
A1 |
A1 |
A2L |
A1 |
A2L |
A3 |
A1 |
Figure 3: Replacements of current refrigerants
Trade-Offs in Efficiency, Cost and Safety
While low-GWP refrigerants deliver environmental benefits, they can introduce new design trade offs:
• Natural refrigerants like CO₂ require higher operating pressures, demanding more robust components and controls.
• Hydrocarbons are efficient and cost-effective but introduce flammability risks, which means enhanced safety mechanisms and careful enclosure management.
• Engineers must also account for characteristics like refrigerant glide. This is the temperature range over which a refrigerant blend evaporates or condenses at constant pressure. It occurs in zeotropic blends (like R-407C) because their components have different boiling points, causing phase change over a range of temperatures rather than at a single point (see figure 5).
• Pure refrigerants and azeotropic blends have little or no glide (see figure 4). This affects heat exchanger design, system efficiency, and maintenance.
Other considerations must also be taken into account, like thermodynamic properties and compatibility with existing infrastructure, balancing upfront cost, operational safety and long-term system efficiency.
What’s Next for the Industry?
The future of refrigeration lies in systems designed around ultra-low-GWP refrigerants, intelligent controls, and modular thermal management.
As the electrification of vehicles and machinery accelerates, thermal systems will need to manage both refrigerant-based cooling and battery/electronics thermal loads in one integrated platform.
With this in mind, you should expect to see further development in:
• Sealed system designs
• New heat pump applications
• Thermal loops optimised around specific refrigerants and use cases
OEMs that partner with experienced thermal management specialists will be better placed to adapt to these rapid changes, while still meeting performance, reliability and regulatory requirements.
What This Means for Your Next Thermal Management Project
F-gas regulations are reshaping the way thermal systems are specified and designed across bus and coach, off-highway, special vehicle, and stationary power applications. They touch everything from refrigerant selection to system architecture, testing, serviceability, and even the digital data that underpins compliance monitoring.
For OEMs and engineers, that means looking beyond immediate project needs and designing with the future in mind, from understanding how refrigerant GWP, charge limits and leak-checking requirements, to new phase-down schedules could affect your platforms over their lifetime.
For decades, our team of thermal management and F-gas specialists has worked directly with design, systems, and validation engineers to help navigate these complexities. We combine over forty years of experience in refrigerant-based cooling, battery and power electronics thermal control, and climate systems for heavy vehicles, with up-to-date understanding of the latest F-gas regulations, standards, and technologies.
Whether you’re developing a new platform or adapting existing systems for upcoming changes, we can help you:
• Identify the most suitable refrigerants and architectures for your application
• Balance performance, compliance, and serviceability
• Integrate flexible, future-proof designs that keep pace with evolving legislation
Our team of thermal experts are here to make sure you stay compliant and stay ahead.
If you’re reviewing refrigerant options or planning your next generation of thermal systems, speak to our team today. We’ll help you turn regulatory challenges into smarter, more efficient, and future-ready designs.
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