Types of refrigerants
1.R134a
R134a remains the most widely used automotive air conditioning refrigerant in China. However, the Kigali Amendment to the Montreal Protocol adopted in October 2016 mandates strict limitations on non-CO₂ greenhouse gases like HFCs. This regulation took effect in China in 2021. R134a faces restrictions primarily due to its high GWP (Global Warming Potential ≈ 1,430).
Global Regulatory Timeline
EU: Banned R134a in new vehicles since 2017 (GWP < 150 required)
USA: Phased out R134a from 2020
2. R1234yf (Honeywell/DuPont)
GWP: 4 (near-zero climate impact)
Advantages:
Drop-in replacement compatible with existing R134a systems
Nearly identical thermodynamic properties
Status: Adopted by 90%+ new EU/US vehicles ([Ref 1][2])
3. CO₂ (R744)
GWP: 1 (lowest among synthetic refrigerants)
Breakthrough:
Transcritical CO₂ cycle (pioneered by G. Lorentzen, Norway [3]) solves high-temperature efficiency issues
Regulations:
German industry standards established in 2015 [4]
Growth Driver: Compatibility with heat pump systems for EVs
4. R290 (Propane)
Eco-profile:
GWP: 3 | ODP: 0 (Ozone Depletion Potential)
Source: Derived from LPG processing
Application: Emerging solution for compact systems
Under the EU’s proposed PFAS (Per- and Polyfluoroalkyl Substances) restriction, synthetic low-GWP refrigerants like R1234yf will be phased out from new vehicles.
Challenges with Alternatives:
R290 (Propane):
Flammability risks (Class A3 per ASHRAE 34) raise safety concerns for automotive applications.
Ongoing debate regarding its viability in mobile AC systems.
CO₂ (R744) as the Future Solution:
Natural refrigerant with near-zero environmental impact (GWP=1, ODP=0).
Comprehensive advantages in safety, eco-friendliness, cost, and performance.
Compressor Oil
The compressor compresses the refrigerant and moves it through the system. Compressor oil reduces friction between moving parts, minimizing wear on components.
Types of Automotive Air Conditioning Compressor Oils
Polyalkylene Glycol (PAG) Oil:
1. Most Common Type: Widely used in modern A/C systems with refrigerants like R134a and R1234yf.
2. Advantages: Provides excellent lubrication and compatibility.
3. Disadvantages: Hygroscopic in nature, absorbing moisture, which reduces its efficiency over time.
Polyol Ester (POE) Oil:
1. Widely Used in Electric Compressors: POE oil is a popular choice in electric and hybrid vehicles, as it is compatible with electric compressors.
2. Advantages: It is less hygroscopic than PAG oil, making it less prone to moisture issues, and is widely compatible with various refrigerants, including natural refrigerants like R744 (CO2).
3. Applications: POE is often used in hybrid and electric vehicle A/C systems, where electrical insulation properties are needed.
4. Disadvantages: Slightly more expensive than PAG, but offers better electrical insulation and broader compatibility.
Mineral Oil:
1. Older Systems: Previously used in A/C systems with refrigerants like R12, now largely phased out due to environmental concerns.
2. Modern Use: Rarely used today in newer automotive systems.
Polyalphaolefin (PAO) Oil:
1. Non-Hygroscopic: PAO oil does not absorb moisture, making it suitable for systems sensitive to water ingress.
2. Advantages: PAO oil offers excellent lubrication, stability at high temperatures, and low moisture absorption.
3. Disadvantages: More expensive than other oils and may not be compatible with all refrigerants.
Rubber seal material resistant to refrigerants and compressor oil
Our EPDM and HNBR materials can be applied to air conditioning systems and are compatible with mixed liquids of refrigerants and compressor oil.
EPDM has a better cost advantage compared to HNBR, and we will prioritize recommending EPDM materials. For the application of R290 refrigerant, we recommend flame-retardant HNBR material.
The following are the basic characteristics of EPDM/HNBR materials applied to HVAC systems.
| HNBR | ||||
| Serial | Characteristic | Unit | Test method | Result |
| 1 | Hardness | Shore A | ASTM D2240 | 73 |
| 2 | Tensile strength | MPa | ASTM D412 | 24 |
| 3 | Elongation | % | ASTM D412 | 243 |
| 4 | Compression set:72h at 150°C | % | ISO 815-1 TypeB | 22 |
| 5 | TR10 | ℃ | ASTM D746 | -24 |
| EPDM | ||||
| Serial | Characteristic | Unit | Test method | Result |
| 1 | Hardness | Shore A | ASTM D2240 | 80 |
| 2 | Tensile strength | MPa | ASTM D412 | 14 |
| 3 | Elongation at break | % | ASTM D412 | 270 |
| 4 | TR10 | ℃ | ASTM D746 | -45 |