From R1234fy to R290/R744,new challenge on rubber seals

The transition of automotive air conditioning refrigerants

Over the past few decades, automotive refrigerants have undergone significant technological changes, transitioning from R12 to R134a/R1234yf and then to R290/R744. These changes come from the specific requirements of automotive air conditioning for refrigerants:

1. Environmental protection: With increasing global concern about climate change, the environmental performance of refrigerants has become a crucial criterion for selection. Low Global Warming Potential (GWP) and zero Ozone Depletion Potential (ODP) are the main goals for current refrigerant development.
2. High Energy Efficiency Ratio: While ensuring cooling effectiveness, refrigerants should have a high energy efficiency ratio to reduce energy consumption and operational costs.
3. Stability and Safety: Refrigerants must maintain chemical and physical stability.They must remain stable across varying temperatures and pressures.This stability prevents corrosion and damage to air conditioning systems. At the same time, it is essential to ensure safe use, especially in high-temperature and high-pressure environments.

R1234yf: R1234yf, a hydrofluoroolefin (HFO), features an extremely low global warming potential (GWP). As one of today’s most widely adopted eco-friendly refrigerants, it effectively reduces greenhouse gas emissions and protects the ozone layer. These environmental benefits drive its dominance in modern refrigeration systems.

R290/744:Recently, the European Chemicals Agency (ECHA) announced that it will soon ban PFAS. The ban on PFAS will lead to the gradual phasing out of R1234yf refrigerants currently used in automobiles. As a result, natural refrigerants like R290 (propane) and R744 (carbon dioxide) may be considered for the next generation of air conditioning systems.

Research demonstrates that R290 and its blends deliver superior performance in air conditioning and heat pump systems. With a lower boiling point than R1234yf, R290 refrigerant operates efficiently in heat pumps even under colder ambient temperatures.

Challenges to use R290/744:The flammability of R290 is a major challenge and the high-pressure technical requirements of R744 also need to be addressed.

Automotive Air Conditioning Compressors and oil

The automotive air conditioning compressor is the core of a car’s AC system. It compresses refrigerant, circulates it through the system, and enables cooling.

Compressor oil is used to lubricate the moving parts within the compressor, reducing friction and extending the compressor’s lifespan. The type of compressor oil varies depending on the vehicle type and the refrigerant used.

Fuel-powered vehicles:

PAG (Polyalkylene Glycol) oil: 
Commonly used in fuel-powered vehicles and compatible with R-134a refrigerant. PAG oil offers good lubricity and chemical stability.

Electric and hybrid vehicles:

POE (Polyol Ester) oil: 
Typically used in electric and hybrid vehicles that use R-1234yf or R-134a refrigerants. Since these vehicles' compressors are driven by electric motors, POE oil is widely used for its better electrical insulation and chemical stability.

Rubber seal O Rings used for HVAC system

OBT Rubber Seal has developed EPDM and HNBR material for different mixture of refrigerant and compressor oil.

We have validated EPDM rubber material has been validated with the refrigerant and compressor oil(POE oil). These mixture include: R134a:SPA2(9:1), R134a :SE-A2(9:1), R134a:Shrieve POE(9:1), R1234yf:SPA2(9:1), R1234yf:Shrieve.

Here is one of the cases of our HNBR material: 
Fluid Resistance 500h at 150℃ in ZE-GLES RB100EV(POE Oil)+R134a(10:90)

Flame retardant grade HNBR material have to be chosed for R290 system.High hardness EPDM material has to be considered for R744 system.

Please contact us for the sealing solution on air conditioning HVAC system.

Reference Reading:

How to measure the hardness: shore A,B,C,D?
How to measure the density of rubber material?
How to Evaluate the Resistance of Rubber to Oils and Other Solvents？
How to Evaluate the Low-Temperature Performance of Rubber?
How to Evaluate the Resistance of Rubber to Oils and Other Solvents？
How to choose between HNBR and AEM?
How to choose between HNBR and FKM(Viton) for O-Ring/gasket?
How choose Between FKM vs FVMQ?
When to use HNBR and Low Temperature HNBR(LT HNBR)?
Low Temperature FKM Rubber: Ideal for Automotive, Aerospace, and Chemical Processing