Which refrigerant replaced R-12 in automotive systems?

The correct answer, HFC-134a, is significant in the context of refrigerants because it was specifically developed as a replacement for R-12, which was phased out due to its ozone-depleting potential. HFC-134a, also known as 1,1,1,2-Tetrafluoroethane, features a much lower impact on the ozone layer while still providing effective thermal performance in automotive air conditioning systems.

The transition to HFC-134a was part of a broader effort to comply with international agreements aimed at protecting the ozone layer, such as the Montreal Protocol. This change was necessary as R-12, a chlorofluorocarbon (CFC), was found to contribute significantly to ozone depletion.

In contrast, R-22, while used often in residential and commercial refrigeration, was not a direct replacement for R-12 in automotive applications. Also, R-410A and R-32 are primarily used in residential and commercial air conditioning systems rather than in automotive systems. Thus, HFC-134a remains the correct and widely recognized replacement for R-12 in automotive contexts.