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

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Refrigerants
Those with ozone depleting potential
Chlorofluorocarbons
CFCs consist of chlorine, fluorine, and carbon. The most common
refrigerants in this group are R11, R12 and R115 (within the blend
R502). As mentioned above, they have been in widespread use
since the 1930s, in nearly all applications, including domestic
refrigeration, commercial refrigeration, cold storage, transport
refrigeration and vehicle air conditioning. Because they contain
no hydrogen, CFCs are chemically very stable, and tend to have
good compatibility with most materials and traditional lubricants
such as mineral oils. Across the range of CFCs, they have a variety
of pressure-temperature characteristics, thus covering a fairly
wide range of applications. Their thermodynamic and transport
properties are generally good, thereby offering the potential for
good efficiency. Their good stability also results in lower toxicity and
non-flammability, thus usually achieving an A1 safety classification.
However, because they contain chlorine, CFCs are damaging to
the ozone layer (section 1), and due to their long atmospheric life,
the CFCs have a high ODP. Similarly, they are strong greenhouse
gases with high GWP. However, they are not controlled by the Kyoto
Protocol because they are controlled and are being eliminated by
the Montreal Protocol. Traditionally, CFCs have been very cheap
and widely available, although with their current phase-out, prices
will rise considerably and availability will lessen.
Hydrochlorofluorocarbons
HCFCs consist of hydrogen, chlorine, fluorine, and carbon. The
most common refrigerants in this group are R22, R123 and R124
(within various blends). As mentioned above, they have been in
widespread use since the 1930s, in nearly all applications, including
commercial refrigeration, cold storage, transport refrigeration,
stationary air conditioning and chillers. Because they contain
hydrogen, HCFCs are theoretically less chemically stable than
CFCs, but nevertheless tend to have good compatibility with most
materials and traditional lubricants such as mineral oils. Across
the range of HCFCs, there are a variety of pressure-temperature
characteristics. Their thermodynamic and transport properties are
typically very good, thereby offering the potential for very good
efficiency. Although some HCFCs have an A1 safety classification,
due to their less stable nature, some HCFCs have A2 (low-toxicity,
lower-flammability) and B1 (higher toxicity, non-flammable) safety
classifications. As with CFCs, because of the chlorine content,
they are damaging to the ozone layer (Chapter 1), although with
a relatively low ODP. Similarly, they are strong greenhouse gases
with high GWP. Again, they are not controlled by the Kyoto Protocol
because they are controlled and are being eliminated by the
Montreal Protocol. Currently, HCFCs are very cheap and widely
available, although with the forthcoming accelerated phase-out,
prices will rise considerably and availability will lessen.
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