Refrigerants
This page contains
details of some of the most common refrigerant chemicals used in todays air
conditioning equipment. The are 3 tables below, each describing one aspect of
the given refrigerant under the following headings:
Refrigerant Chemistry
The table below
contains details as to the properties of the given refrigerants chemicals, such
as its effect on the Ozone layer and Greenhouse effect, as well as its
efficiency as a thermal transfer medium. Below are descriptions of some of the
terms used.
MCE
The MCE, or Maximum Cycle Efficency, is the maximum theoretical effiecy that can
be achieved when using the given refrigerant for heat/thermal transfer. It makes
assumptions such as how well the heat exchanger that is used will work.
ODP
The ODP, or Ozone Depletion Potential, is the the potential for a single
molecule of the refrigerant to destroy the Ozone Layer. All of the refrigerants
use R11 as a calibation and thus R11 has an ODP of 1.0. The less the value of
the ODP the better the refrigerant is for the Ozone Layer and the Environment.
GWP
The GWP, or Global Warming Potential, is a measurement of how much effect the
given refrigerent will have on Global Warming in relation to Carbon Dioxide.
This is usually measured over a one hundred year period. In this case the lower
the value of GWP the better the refrigerant is for the environment.
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Refrigerant
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Chemistry
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R11
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R11
is a single chlorofluorocarbon (CFC) compound. It has a high
chlorine content and ozone depletion potential (ODP) and high direct
global warming potential (GWP).
Maximum cycle efficiency = 90.5%, ODP = 1.0, GWP = 4000
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R22
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R22
is a single hydrochlorofluorocarbon (HCFC) compound. It has a low
chlorine content and ozone depletion potential and only a modest
direct global warming potential. Maximum cycle efficiency = 83.3%,
ODP = 0.05, GWP = 1700
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R134a
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Is
a single hydrofluorocarbon (HFC) compound. It has no chlorine
content, no ozone depletion potential, and only a modest direct
global warming potential. Maximum cycle efficiency = 83.5%, ODP =
0.0, GWP = 1300
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R404A
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R404A
is a ternary blend of hydrofluorocarbon (HFC) compounds (44% = R125,
52% = R143a, 4% = R134a). It has no chlorine content, no ozone
depletion potential, but a high direct global warming potential.
Maximum cycle efficiency = 75.7%, ODP = 0.0, GWP = 3750
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R407C
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R407C
is a ternary blend of hydrofluorocarbon (HFC) compounds (23% = R32,
25% = R125, 52% = R134a). It has no chlorine content, no ozone
depletion potential, and only a modest direct global warming
potential. Maximum cycle efficiency = 80.41%, ODP = 0.0, GWP = 1610
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R410A
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R410A
is a binary blend of hydrofluorocarbon (HFC) compounds (50% = R32,
50% = R125) It has no chlorine content, no ozone depletion
potential, and only a modest global warming potential. Maximum cycle
efficiency 76.3%, ODP = 0.0, GWP 1890
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Refrigerant Legislation
The table below contains details of the current EU
guidelines for the use of different refrigerant chemicals.
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Refrigerant
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Legislation
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R11
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The
EU is proposing to ban the sale of all new and recycled CFC
refrigerants within the EU from 31 December 1999. For maintenance
and servicing there is a proposed ban on CFC refrigerants within the
EU from 31 December 2000. This will apply to virgin, recovered,
recycled and reclaimed refrigerant.
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R22
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Proposed
ban on use in new cooling systems (>100kW) from 2001. Ban on use
in all new cooling systems from 2003. Ban on use in new heat pumps
from 2004. From 2010 only recycled and reclaimed refrigerant will be
permitted for service.
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R134a
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There
are no current restrictions on use of this refrigerant
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R404A
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There
are no current restrictions on use of this refrigerant
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R407C
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There
are no current restrictions on use of this refrigerant
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R410A
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There
are no current restrictions on use of this refrigerant
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Refrigerant Suitability
The table below contains details of the suitability, of
the different refrigerant chemicals, when used in an air conditioning, or heat
exchanger based, system.
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Refrigerant
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Suitability
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R11
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The
low pressures / high volume flows of this refrigerant make it most
suitable for centrifugal chillers. Still found in many chillers
installed during 70's and 80's.
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R22
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Still
the most widely used refrigerant. Its high pressures / low volumes
make it particularly suited to positive displacement compressors
(reciprocating, screw, scroll, and rotary). Wide application range
because of high critical temperature. Excellent performance in heat
pumps and suits all heat exchanger types.
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R134a
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Low
pressures / high volume make R134a most suited to centrifugal and
high speed screw compressors. High critical temperature allows wide
application range. Offers good performance in heat pumps and suits
all types of heat exchanger.
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R404A
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The
high pressures / low volume flows of this refrigerant suits positive
displacement compressors (see R22). Limited application range
because of low critical temperature. Poor performance in heat pumps.
Suits all types of heat exchanger.
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R407C
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The
high pressures / low volume flows of this refrigerant suit positive
displacement compressors (see R22). High critical temperature allows
wide application range. Requires counterflow heat exchangers to
minimise effect of glide and thereby yield optimum performance. Not
suitable for flooded exchangers.
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R410A
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Very
high pressures / low volume flows suit positive displacement
compressors. It has a limited application range because of low
critical temperatures. Suits all heat exchanger types. Very high
operating pressures restricts applications to small units and
systems (<100kW).
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