Current Development Status of HFC-134a for Automotive Air Conditioning

HFC-134a is the refrigerant of choice to replace CFC-12 in automotive air conditioning. The purpose of this bulletin is to communicate the current test status of HFC-134a for use in new automotive air conditioning systems. It expands on the SAE Technical Paper (#890305)-“Performance Comparison of HFC-134a and CFC-12 in an Automotive Air Conditioning System” presented by Du Pont at the 1989 SAE International Congress and Exposition. Topics covered in this paper include:

• Environmental Impact
• Refrigerant Properties
• Heat Transfer
• Refrigeration Performance
• Materials Compatibility
  • Hoses
  • Elastomers
  • Desiccants
  • Metals
• Lubricants
  • Solubility
  • Lubricity

Based on the test work completed, HFC-134a is not a “drop-in” replacement for CFC-12 in most existing systems. Depending on the system, certain design modifications may be required to achieve optimum performance and durability. The significant conclusions from this study are listed on page 12.