The development history of automotive air conditioning refrigerants reflects humanity's continuous balancing act between pursuing comfort and environmental protection. From early toxic substances to modern eco-friendly solutions, this evolutionary process demonstrates the joint progress of technology and environmental awareness.

First-Generation Refrigerants: Early Exploration (1930s-1950s)

Automotive air conditioning systems first appeared in the 1930s, initially using sulfur dioxide (SO₂) and methyl chloride (CH₃Cl) as refrigerants. While these substances provided cooling effects, they had significant drawbacks: sulfur dioxide had a strong irritating odor and was toxic, while methyl chloride was highly flammable. In 1930, General Motors collaborated with DuPont to develop R-12 (dichlorodifluoromethane, CFC-12), a chlorofluorocarbon (CFC) that quickly became the industry standard. R-12 offered excellent cooling performance, chemical stability, and was non-flammable, but its environmental hazards were not yet understood at the time.

Second-Generation Refrigerants: The Golden Age of CFCs (1950s-1990s)

Post-war economic prosperity drove the popularization of automotive air conditioning, with R-12 becoming the absolute dominant refrigerant. This period witnessed the transformation of car air conditioning from a luxury feature to a standard equipment. However, in 1974, scientists discovered that CFCs were damaging the ozone layer, leading to the signing of the Montreal Protocol in 1987, which mandated the gradual phase-out of CFCs. The automotive industry began searching for alternatives to R-12.

Third-Generation Refrigerants: HFCs Transition Period (1990s-2010s)

In the 1990s, the automotive industry turned to hydrofluorocarbons (HFCs), primarily R-134a (tetrafluoroethane). R-134a contained no chlorine atoms and didn't harm the ozone layer, becoming the global standard for automotive air conditioning refrigerants. However, it still had a high global warming potential (GWP=1430). As climate change concerns grew, environmental regulations became stricter. The EU's 2006 Mobile Air Conditioning Directive required all new cars from 2011 onward to use refrigerants with GWP below 150.

Fourth-Generation Refrigerants: Eco-Friendly Solutions (2010s-Present)

Facing stricter environmental requirements, the automotive industry explored various alternatives: R-1234yf (tetrafluoropropene): Developed by Honeywell and DuPont, with GWP=4 and good compatibility with existing systems, though it raised mild flammability concerns. Currently adopted by mainstream manufacturers like Mercedes and BMW. CO₂ (R-744): A natural refrigerant with GWP=1, but requiring high-pressure systems (about 100bar), with Volkswagen Group as its main proponent. Blend refrigerants: Such as R-152a (difluoroethane) and others, balancing performance and environmental friendliness.

Future Trends and Challenges

The future development of automotive refrigerants faces multiple challenges:

Increasingly stringent environmental regulations: Global restrictions on high-GWP substances continue to tighten

Special requirements of electric vehicles: EV air conditioning systems must address both cooling and battery temperature management

Balancing system efficiency and cost: New refrigerants often require system redesigns, increasing costs

From R-12 to R-1234yf and CO₂, the evolution of automotive air conditioning refrigerants embodies the combination of technological innovation and environmental responsibility. Moving forward, with the advancement of carbon neutrality goals, refrigerant technology will continue to develop toward zero environmental impact while meeting growing demands for automotive comfort. This history is not only a microcosm of technological progress but also a testament to the awakening of human environmental awareness.