Manual for Refrigeration Servicing Technicians - UNEP - Division of ...

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Refrigerants
Hydrofluorocabons (HFCs)
HFCs consist of hydrogen, fluorine, and carbon. The most common
refrigerants in this group are R134a, R32, R125 and R143a (mostly
within blends, such as R404A, R407C and R410A). They have been
in large scale use since the 1990s, in nearly all applications that
have traditionally used CFCs and HCFCs, including domestic and
commercial refrigeration, cold storage, vehicle air conditioning,
transport refrigeration, stationary air conditioning and chillers.
HFCs are generally chemically very stable, and tend to have good
compatibility with most materials. However, they are not miscible
with traditional lubricants, so other types of synthetic oils must be
used. Across the range of HFCs, there are a variety of pressuretemperature
characteristics. Their thermodynamic and transport
properties range from fairly to very good, thereby offering the
potential for good efficiency. Although some HFCs have an A1 safety
classification, some have A2 (low-toxicity, lower-flammability) safety
classifications. Unlike CFCs and HCFCs, they contain no chlorine,
and are thus not damaging to the ozone layer (Chapter 1). However,
due to their long atmospheric lifetime, they are typically strong
greenhouse gases with high GWP. They are controlled by the Kyoto
Protocol. Currently, HFCs carry a moderate price, with the blends
being more expensive. Although numerous countries are developing
legislation to control the use and/or emissions of HFCs, many are
widely available, and will continue to be so for the foreseeable future.
Those without ozone depleting potential 4
Heat transfer fluids 4
Using Refrigerant Blends – issues and concepts 4
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