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Natural Refrigerant Technologies

TFA contamination from fluorinated gases used in mobile air-conditioning systems and already available PFAS-free alternatives (R290, R744)

Summary

As the automotive industry transitions toward PFAS-free solutions, refrigerant selection is becoming an increasingly important topic. This white paper explores the relationship between PFAS regulations and refrigerants used in vehicle air-conditioning and heat pump systems, including their potential impact on trifluoroacetic acid (TFA) emissions.

It also highlights practical pathways toward PFAS-free mobility, including the successful commercialization of R744 (CO₂) technology and advancements in utilizing R290 (propane).

Key Findings

Regulatory urgency

Since implementing R1234yf in passenger vehicles in 2017, the annual TFA emissions are rising strongly in Europe. This will continue for the next ten years at least, unless a PFAS restriction leads to an early switch to natural refrigerants. Only a strict and timely adoption of natural refrigerants prior to 2035 could avoid an extremely high environmental TFA burden for the coming decades.

Technical readiness

Thermal management systems using the PFAS-free natural refrigerant R744 (CO2) are already established in series applications in battery electric vehicles. Concepts using refrigerant R290 (propane) are under active development and validation. This shows that compliance with stricter PFAS regulation is technically achievable and more importantly, already available for the mass market.

Policy aspect

It is a fact that for all vehicles that use an electric compressor in their thermal management system, alternatives are available and have been proven over one million times in the field. This includes BEVs, PHEVs and all HEVs with system voltages of at least 48 V. Comparison of regulatory scenarios indicates that refrigerant choice can reduce TFA emissions more quickly by making use of all these already available alternatives in all vehicles with an electric compressor.

Table of Contents

  1. Introduction
  2. History of mobile A/C system refrigerants
  3. R1234yf: Environmental Considerations and TFA Trends
    1. Degradation mechanisms of R1234yf and R134a
    2. Wet deposition causes TFA concentrations in precipitation
    3. TFA modeling of the passenger car fleet in Europe
  4. TFA measurements
    1. Precipitation
    2. Non-agricultural materials such as tree needles
    3. Food and beverages
    4. Human blood
  5. Effects of TFA on the human body
  6. Availability of Alternatives (AoA)
    1. More than one million VW MEB vehicles with PFAS-free refrigerant
    2. Thermal management with R290
    3. R744 thermal management systems – next generation
  7. Global view on fluorinated gases and TFA
  8. Conclusions
  9. References
  10. Annex
    1. TFA Model assumptions and input data

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