What Happens When R124 & R134 Are Mixed?

The Problem

• The damage that CFCs can do to the ozone layer is well-documented; in fact, the research goes all the way back to 1974, when M.J. Molina and F.S. Rowland first theorized the potential damage in "Nature" magazine. Because the ozone layer protects the Earth from UV radiation, which leads not only to skin cancer in humans but is also dangerous for such species as phytoplankton, stopping ozone layer depletion was a vital priority.

Solving the Problem -- R134a

• Many researchers sought a coolant solution that was either a single compound or an azeotropic (or almost azeotropic) mixture. An azeotrope maintains consistent physical properties and composition even after evaporation, which is less damaging to the ozone layer. R134a was identified as a refrigerant that could work in a mixture, because it doesn't have any chlorine in it.

Combining R134a

• Scientists began looking for another component to mix with R134a to make a stable mixture. R124 combines with R134a to form a mixture that maintains a stable vapor pressure, even after evaporating, and has less of a harmful effect on the ozone layer than many other mixtures. Research for a patent on this mixture shows that these two virtually act like an azeotropic mixture when combined, meaning that the damage to the environment falls far more within tolerances than other mixtures or refrigerants.

Current Patentholders

• At the time of publication, Jack Jones, at the California Institute of Technology, holds U.S. Patent #5,512,197 for this combination between R134a and R124. Currently, he combines 79 to 90 percent R134a and about 10 to 30 percent R124. The patent was filed in October, 1993, and remains one of the leading alternatives to more harmful refrigerants.