je0c00338_si_001.pdf (388.51 kB)
(R)Evolution of Refrigerants
journal contribution
posted on 2020-07-02, 20:03 authored by Mark O. McLinden, Marcia L. HuberAs we enter the “fourth
generation” of refrigerants,
we consider the evolution of refrigerant molecules, the ever-changing
constraints and regulations that have driven the need to consider
new molecules, and the advancements in the tools and property models
used to identify new molecules and design equipment using them. These
separate aspects are intimately intertwined and have been in more-or-less
continuous development since the earliest days of mechanical refrigeration,
even if sometimes out-of-sight
of the mainstream refrigeration industry. We highlight three separate,
comprehensive searches for new refrigerantsin the 1920s, the
1980s, and the 2010sthat sometimes identified new molecules,
but more often, validated alternatives already under consideration.
A recurrent theme is that there is little that is truly new. Most
of the “new” refrigerants, from R-12 in the 1930s to
R-1234yf in the early 2000s, were reported in the chemical literature
decades before they were considered as refrigerants. The search for
new refrigerants continued through the 1990s even as the hydrofluorocarbons
(HFCs) were becoming the dominant refrigerants in commercial use.
This included a return to several long-known natural refrigerants.
Finally, we review the evolution of the NIST REFPROP database for
the calculation of refrigerant properties.