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Why CFC Free?
Chlorofluorocarbons, or CFC’s, have
served the air conditioning and
refrigeration industry for more than 50
years. One of their primary attributes ...
stability ... has been found to be a cause
of harm to our environment. And,
therefore, the international community
has agreed on regulations to bring about
their phaseout.
More recently it has been found that
CFC’s are powerful global warming gases,
Figure 2. Although CFC’s make up only
0.0000001 percent of the volume of the
atmosphere, they contribute 21 percent of
global warming. Clearly, the message is
to quickly reduce and eliminate the use of
CFC’s.
Figure 2: Global warming gases.
CFC’s are the primary cause of the ozone
depletion. Contributions to ozone
depletion, with CFC’s making up more
than 70 percent of the man-made ozone
depleting chemicals in the atmosphere
today, are shown in Figure 1.
What Are The Alternatives
To CFC’s
Figure 1: Stratospheric chlorine
(Copenhagen agreements).
The primary alternatives to become CFC
free in chillers are shown in Table 2.
Extensive testing has been completed
and all three are available globally.
Critical Questions
The international community has agreed
to phase out the use of CFC’s, with
schedules for developed and developing
countries, Table 1.
5
What is the status of global warming
regulations and how will it affect our
industry?
6
How do we evaluate the combined
effects of ozone depletion and global
warming?
7
What is the future of so called “third
generation” refrigerants?
8
What are the best practices owners are
using to manage the CFC-free transition
with the least possible cash outlay?
1
What are the alternatives to CFC’s?
2
Are the alternative refrigerants safe?
3
How can microprocessor-based
technology be used to reduce refrigerant
emissions and improve safety of all
refrigerants?
4
What is the status of ozone depletion
regulations and how will it affect the
long-term availability of all refrigerants?
Table 1: Montreal Protocol CFC phaseout dates.
Date
Developed Countries
January 1, 1996
CFC Phaseout
July 1, 1999
January 1, 2005
January 1, 2007
January 1, 2010
Developing Countries*
CFC’s capped
CFC’s reduced by 50%
CFC’s reduced by 85%
CFC phaseout
Table 2: Alternative refrigerant choices.
Existing
Alternative
CFC-11
HCFC-123
CFC-12
HFC-134a
HCFC-22
HCFC-22/410A/407C
Are The Alternative
Refrigerants Safe?
Proud. The dictionary defines proud as
...“having or displaying earned self-respect
or self-esteem”. Using this definition,
our industry can truly be proud of its
accomplishments in handling the safety of
alternative refrigerants.
Clearly, in the early 1990’s, the safety
of alternative refrigerants was, at first,
questioned. Today, after years and years
of testing and experience, we know
that …for the HVAC industry… the
alternative refrigerants are actually
as safe or safer than the refrigerants
they replace.
* Article 5 countries.
©American Standard Inc. 1998
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Table 3: Comparison of various refrigerants.
Low Pressure
Acute
CFC-11
HCFC-123
Anesthetic Effect
35.000 ppm (10 min)
40,000 ppm (10 min)
LC50 (40 hr)
26,000 ppm
32,000 ppm
Cardiac Sensitization
5,000 ppm
20,000 ppm
Pressure at 72 F
1.5” Hg vacuum (liquid)
5.6” Hg vacuum (liquid)
High Pressure
HCFC-22
HFC-134a
140,000 ppm (10 min)
205,000 ppm (4 hr)
>300,000 ppm
>500,000 ppm
50,000 ppm
75,000 ppm
126 psig pressure (gas)
74 psig pressure (gas)
Definition of ppm: parts per million.
It’s important that one understands what
the phrase ”the alternative refrigerants are
safe“ means. The position supported by
every major industry organization
(ASHRAE, ARI, U.S. EPA, all federal and
state agencies and all of the code writing
bodies) is that “All refrigerants, both
traditional and alternative, can be used
safely as long as two criteria are met:
•
Safe handling refrigerant practices are
followed and
•
Equipment rooms conform to ASHRAE
Standard 15-1994 requirements.”
Today, this sounds so logical that the
question may be “What was the
problem?”, especially for some of the first
alternative refrigerants, i.e. HCFC-123 and
HFC-134a.
After an entire lifetime of highconcentration exposures to both HCFC123 and HFC-134a, only very late in the life
of test animals did a higher incidence of
benign tumors develop. However, when
people heard benign tumors, all they really
heard was “tumors.” And when “tumor”
is the only word heard, it’s human nature
to think “cancer.” This simply is not true.
Benign is the operative word and benign
means nonmalignant… noncancerous.
Clearly this is good news for our industry.
With more and more tests complete,
there is more good news. The tumors that
were discovered have shown to be
relevant to the test animals, but showed
little or no relevance to man. Quoting Dr.
William Brock, senior toxicologist at
DuPont, in the August 1997 issue of
Building Operating Management,
“…the tumors that occurred with HCFC123 have little or no relevance to human
beings.” Armed with this information,
DuPont (the leading manufacturer of the
alternative refrigerants) has raised HCFC123’s acceptable exposure limit (AEL) to
50 ppm. In addition, DuPont’s move
follows the recommendation of the
American Industrial Hygiene Association (a
totally independent group) to set HCFC123’s workplace environmental exposure
limit (WEEL) at the 50 ppm level.
Figure 3
The significance of this move is that
HCFC-123’s AEL was 10 ppm. With more
testing, it was moved to 30 ppm and now,
with even more testing complete, has
moved up to 50 ppm, Figure 3.
In over 20,000 machine installations, the
industry has proven that equipment room
exposure levels can typically be held at
levels less than .5 ppm. That is over a
magnitude lower than the 10 ppm AEL set
in 1991. The move up first to 30 ppm and
now to 50 ppm increases the difference
between typical exposures and the
established AEL to two magnitudes. Or,
said a different way, exposures are most
often over a hundred fold less than
HCFC-123’s established AEL of 50 ppm.
However, with all of this good news, it’s
imperative we don’t miss the most
important point; the principle concerns
originally raised resulted from lifelong
exposure testing. While lifelong exposure
concerns may be appropriate for a worker
working in a chemical plant that has an
inexhaustible supply of material, it
certainly is not the primary issue for the
HVAC industry. An HVAC service
technician or an operator simply cannot
not be exposed to lifetime refrigerant
limits. There simply isn’t enough
refrigerant in the machines to sustain a
lifelong exposure at the concentrations of
the established AEL, let alone the
concentrations used to expose the test
animals.
For the HVAC industry, the issue is not
one of long-term exposure but of shortterm exposure. If a service technician or
operator is doing what they have to do by
law today, recovering the refrigerant,
exposures are extremely short-term in
nature ... typically less than five minutes.
That is precisely why, for the HVAC
industry, the issue is short-term and not
long-term exposure. And, from a shortterm exposure standpoint, the alternative
refrigerants are less ... not more ... toxic
than the refrigerants they replace; a fact
confirmed repeatedly in a number of
industry and U.S. EPA. publications.
Table 3.
There are three key indicators of
short-term exposures:
•
Anesthetic effects
•
LC50
•
Cardiac sensitization.
In every case, HCFC-123 exposure
ratings are better than those of CFC-11,
the refrigerant it replaces.
Anesthetic effects: This is the ability of
the chemical to cause drowsiness in the
test animals. HCFC-123’s 10-minute
anesthetic exposure level is a full 10
percent higher (less toxic) than the
CFC-11, the time-tested refrigerant it
replaces.
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Figure 4
in less than seven minutes and, without
mechanical ventilation, could fill a space
25 by 30 by 7 feet with 1,000,000 parts
per million. Now, if it can get to a million
parts per million in less than seven
minutes, how long would it take to reach
the 75,000 parts per million cardiac
sensitization threshold of HFC-134a. Not
long! This is precisely why mechanical
ventilation of all refrigerants is so
important.
The point is, there is a lower risk of getting
to the lower exposure numbers with a
lower pressure refrigerant. From this
perspective, lower-pressure refrigerants
do have a safety advantage.
LC50: LC50 stands for the lethal
concentration at which 50 percent of the
test animals perish after a given period of
time; in this case, four hours. HCFC-123’s
LC50 exposure level is 25 percent higher
(less toxic) that CFC-11. Further, to put
these values into perspective, HCFC-123’s
LC50 is 32 times higher (less toxic) than
what the U.S. Occupational Safety and
Health Administration (OSHA) defines as
toxic and over 320 times higher than
OSHA’s definition of highly toxic.
Cardiac sensitization: Of the three,
industrial hygienists frequently agree that
cardiac sensitization, which is the ability to
cause cardiac arrhythmia under stress, is
the most important. In this case, the
exposure level of HCFC-123 is 400
percent better than that of CFC-11.
In every category, HCFC-123 short-term
exposure ratings are higher, better, less
toxic than the time-tested CFC-11.
However, when compared to HCFC-123,
HFC-134a’s numbers are even higher.
Therefore it would appear HFC-134a, from
a short-term perspective, is less
dangerous than HCFC-123. That is not
necessarily true. In fact, in case of an
accidental release of refrigerant, such as a
crack in a sight glass or a line breaking
because of vibration or a valve packing
failure, one will typically have a higher risk
of getting to higher concentrations with
HFC-134a than the lower concentrations
with HCFC-123.
To explain: HCFC-123 is a low-pressure
refrigerant, which means that if there is a
leak the air usually leaks into the machine
instead of refrigerant leaking out. HFC134a, however, is a high-pressure
refrigerant in which case the refrigerant
cannot only leak out, it can rush out.
To demonstrate this point, imagine using
two cylinders. One cylinder is in a vacuum
while the other is pressurized to 35 psig
(HFC-134a’s pressure at 40 F). The
evacuated cylinder simulates the
operation of a low-pressure machine,
which typically operates in a vacuum.
The pressurized cylinder, in turn, simulates
the operation of a high-pressure machine
with HFC-134a; even at its lowest
pressure point, the evaporator.
Now imagine attaching a balloon to
each cylinder. When the valve on the
evacuated cylinder is opened, it will
simply try to draw the balloon/air into
the cylinder. Similarly, if a leak were to
develop on a low-pressure machine, air
will typically be drawn into the machine
instead of refrigerant leaking out.
However, when the valve is opened on
the tank that has been pressurized to 35
psi, it can be compared to a tire blowout,
Figure 4. A high-pressure refrigerant will
not only leak out, it can rush out. For
example, a 500-ton HFC-134a machine
uses three to five pounds of refrigerant
per ton. Even at three pounds per ton,
that’s 1,500 pounds of refrigerant.
Essentially, the entire 1,500-pound charge
can exit the machine through a 1-1/2” hole
There is also a second, and perhaps
more important, safety advantage with
low-pressure refrigerants. Ask any
experienced service technician. They will
tell you that one of the single greatest
dangers of all halogenated refrigerants is
asphyxiation. That danger was
underscored by an accident in Anchorage,
Alaska, where an installation used an ice
making machine with somewhere
between 2,000 and 4,000 pounds of
R-22. A young assistant rink manager, not
fully trained on the equipment, walked on
the job that fateful Monday morning. He
had been told to change out the core on
the filter dryer.
Because
the machine was making ice,
he was afraid to shut it down and he
didn’t know what the valves did, so he
was afraid to shut them off. He took a
wrench and started to back out the bolt.
When the bolt got to the last land, it
blew… so fast that the 24-year-old
assistant did not make it out of the
equipment room. Further, because the
room was not designed to today’s
ASHRAE Standard 15 requirements, the
refrigerant escaped engulfing the skating
rink and the swimming pool, injuring
another 34 people.
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It is not difficult to understand why
asphyxiation is one of the greatest
dangers of all refrigerants. All halogenated
refrigerants are heavier than air. They all
displace air, which means they can
displace oxygen. And that means a person
can asphyxiate ... or drown ... in refrigerant
just as surely as they can drown in water.
The point: If asphyxiation is one of the
single greatest dangers of all refrigerants
…and it is… is there not a significant
advantage in using low-pressure
refrigerants? Remember, with lowpressure refrigerants, air will typically leak
in. High-pressure refrigerants will typically
rush out.
If the young assistant in Anchorage had
been working on a low-pressure machine
and backed out the bolt, when the bolt
reached the last land he’d have heard the
air being sucked in and would still be alive
today. Low-pressure machines have two
safety advantages:
1
A lower risk of getting to the established
exposure levels and
2
A significantly lower risk of asphyxiation.
Does this mean that one cannot safely
use high-pressure refrigerants? No! Refer
again to the position held by ASHRAE, the
EPA and many others. Every one of the
alternative refrigerants can be used safely,
as long as safe refrigerant handling
practices and ASHRAE Standard 15-1994
requirements for equipment room design
are followed.
How Can MicroprocessorBased Technology Be Used To
Reduce Refrigerant Emissions
And Improve Efficiency Of
All Refrigerants?
One of the key questions asked today is
“How can microprocessor-based
technology be used to reduce refrigerant
emissions and improve the safety of all
refrigerants?”
ASHRAE Standard 15-1994 requires
refrigerant monitoring for all refrigerants.
The key question is, “At what level is the
microprocessor-based monitor able to
detect refrigerant concentrations?” Only
with a refrigerant monitor that can
accurately measure low refrigerant
concentrations, in the range of 1 to 3
ppm, can minute leaks be detected.
When detected, the monitor not only can
activate the necessary alarms; it can also
automatically alert the appropriate service
The point is that “minutes of operation”
can be used to indicate whether a
machine is “tight” or not.
company to the potential of a refrigerant
leak so it can be fixed. Monitoring can
provide an inexpensive means by which
trained experts can constantly oversee
equipment room operation and have the
ability to respond quickly; even to very
small refrigerant loss, providing an
excellent refrigerant asset management
tool.
Monitoring also allows refrigerant
concentrations to be documented,
providing a number of benefits:
•
Helps employees know they are working
in a safe environment.
•
Documents via printed reports that
refrigerant concentrations were
consistently maintained below the
appropriate AEL.
•
Generates automated reports providing
unquestionable documentation that even
minute levels of refrigerant concentrations
have been monitored and recorded. This
benefit is especially important since EPA
regulations for reduced emission levels
may increasingly include requirements for
verification of operating procedures that
control CFC, HCFC and HFC equipment
room emissions.
•
Provides an extra measure of safety for all
refrigerants. Oxygen deprivation sensors
were required by ASHRAE Standard 151992 for “A1” refrigerants and were
typically set to alarm when the
percentage of oxygen was less than 19.5
or 195,000 ppm. By monitoring refrigerant
levels with highly accurate sensors, it is
possible to provide an extra margin of
safety for all refrigerants. For this very
reason, ASHRAE Standard 15-1994 was
revised to require refrigerant sensors for
all refrigerants.
•
Detects even the minute refrigerant leaks
so they can be repaired quickly.
Another good idea that has come of age
deals with the purge unit. There are
purges on the market today with
essentially zero emission of refrigerant
losses. For example, Trane’s purge loses
less than .002 pounds of refrigerant/
pound of dry air or, on a typical 500-ton
centrifugal chiller, less than half an ounce
of refrigerant per year. This purge also has
a secondary advantage: It incorporates a
microprocessor-based run-time meter that
displays operation in minutes.
The key is that you can readily tie the
purge’s run-time meter into a Trane Tracer®
building automation system to log, report
and, should the controller start to log
excessive operation, dial out an alarm to
the service company alerting it to the fact
that a leak is developing and needs to be
fixed.
However, the purge’s run-time is but one
of a myriad of “good ideas” listed in
ASHRAE Guideline 3-1996. This document
offers a number of good common-sense
ideas and excellent examples of how
microprocessor-based controls can be
applied to improve the refrigerant asset
management of all refrigerants.
As refrigerants become more and more
expensive, they are essentially becoming
an asset. Ideas like tying both the
refrigerant sensor and the purge to the
automation system, as well as other
refrigerant asset management strategies
outlined in ASHRAE Guideline 3, are
becoming standard practice. This is
especially true now that both the purge
and sensor can be factory tied into the
Tracer building automation system using
nothing more than a twisted pair
of wires.
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“ Near Zero” Refrigerant
Emissions Chiller
As early as 1993, Trane made available a
“near zero” refrigerant emissions HCFC123 centrifugal chiller, Figure 5. This is a
technological breakthrough that produces,
through the use of a total systems
approach, a more than 50-fold reduction in
chiller refrigerant emissions when
compared to machines manufactured 15
years ago.
Figure 5: Trane “near zero” emissions centrifugal chiller.
Trane’s total systems approach not only
includes improved construction. It also
radically improves purge unit efficiencies,
modified leak testing technologies,
improved refrigerant handling and
recovering techniques, and the use of a
low-pressure refrigerant design where air
tends to leak into the machine versus
refrigerant leaking out.
This total system concept means that the
chillers can be operated with “near zero”
emissions during all three phases of chiller
operation:
1
Normal operation.
2
Minor service.
3
Refrigerant transfer/major service.
Figure 7: Trane Zero Emission™ purge check.
By examining each of these three phases
of operation, one can see how these new
technologies are used to produce a “near
zero” emissions centrifugal chiller.
Losses During Normal Operation
“Near zero” emissions Trane chillers have
unique early warning systems to detect
and warn of chiller leaks. These controls
alarm at the first indication of unusual
purge operation. They directly monitor the
presence of refrigerant that has escaped
from the chiller. The loss of refrigerant due
to unnoticed catastrophic leaks can
virtually be eliminated.
Leaks: Leaks have historically accounted
for over 41 percent of the refrigerant loss;
and flare fittings have been identified as a
major contributor to these leaks.
The “near zero” centrifugal chiller has over
85 percent fewer flare fittings than
machines produced just 10 years ago.
However, flare fittings are only a part of
the over 200 design changes included in
the “near zero” emissions chiller. The
“near zero” emission level is made
possible by the low-pressure chiller
design. In the only section of the machine
that is pressurized during operation, the
condenser, the pressure differential to
atmosphere is over 20 and 30 times less
than medium-pressure and high-pressure
refrigerant, respectively (Figure 6).
This is significant because pressure
differential is the driving force of leaks.
Combining the substantially improved
hermetic integrity with inherent low
pressure characteristics of HCFC-123 is
critical to obtaining the “near zero”
emissions of these chiller designs.
Another major factor in the “near zero”
emissions chiller design was the
development of a Zero Emissions™ purge,
Figure 7. This purge has refrigerant losses
of less than .002 pounds of refrigerant per
pound of air, which equates to within two
significant digits... a zero emissions purge.
Figure 6: Leaks are pressure dependent.
This means that, on a typical 500-ton
machine, the loss from the purge is less
than half an ounce of refrigerant annually.
These improvements mean that purge
losses have been virtually eliminated as a
source of refrigerant loss.
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Losses During Minor Service
Minor service for centrifugal chillers is
characterized by procedures such as
changing purge and oil filters, etc. The
“near zero” emissions centrifugal chiller is
equipped, as standard, with a complete
system of isolation valves to allow
evacuation and extraction of nearly all
refrigerant from the filtration system,
Figure 8, reducing emissions during
minor service to near zero losses.
Loss During Refrigerant Transfer
The “near zero” emissions chillers are
equipped with special valving
arrangements that allow refrigerant to be
added to the equipment and recovered
with virtually nonmeasurable losses of
refrigerant.
Low Total Loss Rate – Prove It
In the largest study of its kind, a study
involving nearly 3,000 machines of which
some had been installed for nearly a
decade, Trane did exactly that… proved it!
Results of the study indicate that not only
the leak rate, but the entire loss rate, was
less than .46 percent. The results shown
in Figure 9 are outstanding for two
reasons: First, the rate was nearly 10
percent better than the .5 percent rate
claimed. And second, these values
represent total “loss” rate, which means
they also include accidental losses
through rupture disks, etc. This study
provided formal documentation of the fact
that these machines loss rates are so low
they are essentially a closed system.
Figure 9
These valves are specially designed to be
used with high efficiency recovery and
evacuation equipment, also manufactured
by Trane, that captures over 99.94 percent
of the refrigerant charge of the machine.
This means that if a typical 500-ton
machine were to be opened up for major
service, such as motor repair, less than
0.5 pounds of refrigerant would be lost to
the atmosphere.
Finally, the key to designing the “lowest”
emissions chiller is to turn to the
technology that inherently allows for low
emissions. This statement simply
acknowledges the fact that the driving
force of leaks is pressure differential to the
atmosphere. Figure 6 illustrates the
substantially lower pressure, i.e. low
potential for leaks of a low-pressure
HCFC-123 system vs the higher-pressure
HFC-134a or HCFC-22 design.
Figure 8: Service isolation valves
reduce minor service emissions.
Why A “Near Zero”
Emissions Chiller?
One question the reader may be asking is
“Why did Trane spend hundreds of man
years and millions of dollars developing
the “near zero” emissions chiller?” Clearly,
there are major environmental benefits in
using an essentially closed system.
However, one of the additional benefits is
that it provides a sound answer to a
concern raised on the long-term availability
of the alternative refrigerants.
Refrigerant Availability:
Economic Perspective
Many times, refrigerant availability is
viewed from an emotional perspective
when it should be viewed from an
economic perspective. Consider the
following: An obvious statement is “If a
chiller never lost refrigerant, one would
never have to be concerned about
replacement refrigerant availability.” Said
another way, “If one were to minimize
emissions or, ideally, reduce them to zero,
the cost of assuring replacement
refrigerant availability would be very low
indeed.” Therefore, the fundamental task
is to assess the replacement refrigerant
availability/emissions risk and to weigh it
against the cost savings generated via
improved efficiency and lower
maintenance costs.
This effort to reduce refrigerant emissions
is one of the major reasons why Trane
developed the “near zero” emissions
centrifugal chiller.
To put a 0.5 percent emission rate into
perspective, consider the following
example: A typical 500-ton Trane
CenTraVac® chiller, assuming two pounds
of refrigerant per ton, has an operating
charge of 1000 pounds. At a 0.5 percent
emissions rate, this chiller would lose only
five pounds of refrigerant per year.
(1000 pounds of refrigerant x .005
emission rate = five pounds of refrigerant
per year.)
In a 30-year lifetime, the chiller would lose
only 150 pounds of refrigerant; an amount
that can be contained in two six-gallon
jugs, Figure 10. (Containers shown are
illustrative only. Proper containers must be
used for actual storage of refrigerant.)
And what would be the cost of this
lifetime supply of refrigerant? Today, the
cost of HCFC-123 is about $4/pound.
Therefore, 150 pounds... or a lifetime
supply of HCFC-123 for a typical 500-ton
chiller... would be only $600. In fact, one
could buy a complete charge of refrigerant
for $4,000 and put it into a properly
constructed vessel or put it into a
refrigerant bank. In a worst-case scenario
where the chiller would lose a complete
charge, something that is unlikely to
happen with a low-pressure chiller, a
lifetime of refrigerant plus one complete
extra charge could be purchased for
$4,600.
Figure 10
Compare this cost to the operating cost
savings for a typical HCFC-123 chiller.
Today HCFC-123 centrifugals are
frequently five to 10 and, in many cases,
20 percent more efficient than their HFC134a or HCFC-22 counterparts. Trane
centrifugals are selectable at a 0.48 to
0.49 kW/ton or better at ARI conditions,
from 300 to nearly 2500 tons.
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HFC-134a and HCFC-22 centrifugals are
typically limited to 0.54 to 0.60 kW/ton
and higher. Owners and designers can
easily prove that this efficiency difference
exists simply by taking the different
centrifugal chiller manufacturers for an
efficiency test drive, at both full and partload conditions. Ask the various
manufacturers for their best efficiencies at
the job’s specific conditions. One will find
that, indeed, HCFC-123 chillers are
typically five to 20 percent more efficient.
What’s the point? The point is that the
efficiency difference is worth a great deal
of money. Amounts not only many times
that of the cost of a lifetime supply of
refrigerant, but frequently more than
twice the initial cost of the entire chiller.
Life-Cycle Costing
It is a sound idea to perform a life-cycle
cost analysis and, clearly, the best way to
perform life-cycle analysis is to use
credible energy analysis programs such as
Trane’s TRACE® or System Analyzer™.
These programs can account for full-load,
part load and ambient relief factors on an
hour-by-hour or bin weather analysis basis,
respectively. We encourage the use of
these programs whenever possible.
However, an equivalent full-load hour
analysis provides a close estimate of the
operating cost savings; and the beauty
is that each step is simple and easy
to follow.
Consider a job with the following
characteristics:
•
A 500-ton centrifugal.
•
2000 equivalent full load hours (EFLH).
•
0.50 kW/ton HCFC-123 centrifugal
compared to a 0.60 kW/ton HFC-134a
centrifugal chiller or a .10 kW/ton
difference.
•
$.10 kWh energy cost, including
demand.
500 tons x 2000 EFLH x 0.10 kW/ton
difference x $.10/kWh = $10,000/year
x 30 years = $300,000.
That $300,000 in energy savings is five
hundred times greater than the $600 lifecycle cost of the refrigerant consumed by
the chiller. Said another way, an HCFC-123
centrifugal chiller with a 0.10 kW/ton
efficiency advantage will provide more
energy savings in one month than the
replacement refrigerant would cost
throughout its lifetime, which is $600.
Finally, because the chiller’s first cost is
approximately $250/ton or $125,000, the
$300,000 represents an amount over
twice the entire initial cost of the machine.
This means that the chiller could be retired
a little over halfway through its life and an
entirely new machine purchased with the
savings.
Why the efficiency advantage for HCFC123? First and foremost, HCFC-123 has
the highest thermodynamic efficiency of
all alternative refrigerants, Figure 12.
Figure 12: Efficiency comparison
for various refrigerants.
A way to visually internalize the
importance of life-cycle costing is to
review Figure 11. To understand the
relative differences between the cost of
refrigerant, the cost of the chiller and the
cost to operate the chiller is to understand
why efficiency is so important and why
focusing solely on what refrigerant a chiller
uses is simply inadequate.
Figure 11: Operating cost comparison.
Energy Efficiency Is The Key
One cannot simply concentrate on the
ODP or GWP of a refrigerant. The key to
environmental responsibility lies in energy
efficiency. And on the energy front, there
is good news. With 1998 as the base year,
Table 4 shows that in just 20 years the
industry has made more than a 50
percent improvement in efficiency.
Table 4: Chiller efficiency progress.
Efficiency kW/Ton
Year*
Average
Good
1978
.80
.72
1980
.72
.68
1990
.65
.62
1991
.64
.60
1993
.63
.55
1995
.61
.52
1997
.60
.49
1998
.59
<.48
*1978-1998…over 50 percent improvement.
Today, HCFC-123 chillers are leading this
trend and typically demonstrate a five to
20 percent efficiency advantage over
chillers using other alternative refrigerants.
Specifically, Trane’s HCFC-123 Earth•Wise
CenTraVac can be selected at .48 to .49
kW/ton or better across the line, from 300
to nearly 2500 tons at ARI conditions.
Second, and equally important, is the
inherent design of the Trane machine,
including:
•
A direct-drive design that eliminates gear
losses.
•
A multi-stage compressor design to
optimize the efficiency and maximize the
operating range of the compressor.
•
The use of a refrigerant economizer cycle.
•
The use of low condenser and evaporator
approach temperatures (leaving water
temperature less refrigerant temperature),
results in more heat transfer surface.
However, the .48 to .49 kW/ton is at full
load conditions. Via the use of patented
inlet guide vanes or an Adaptive
Frequency™ drive, the part-load
performance is even better. One only has
to compare the applied part load values
(APLV) of the various chillers to see that
the Earth•Wise CenTraVac is not only
more efficient at full load, but even more
so at part load; differences that can be
confirmed via factory witness tests.
This efficiency not only significantly
reduces operating cost, it has a major
environmental impact as well. Consider
this example: If every centrifugal chiller in
the world were a .48 kW/ton vs a .56 kW/
ton, it would mean annual savings of over
17 billion pounds of power plant generated
CO2, 64 billion grams of SO2 and over 27
billion grams of NOX. In CO2 emissions
alone, this is the equivalent of taking over
two million cars off the road or planting
nearly a half billion trees.
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What Is The Status Of Ozone
Depletion Regulations And
How Will It Affect The
Long-Term Availability Of
All Refrigerants?
The headlines of the September 22, 1997,
issue of Air Conditioning, Heating and
Refrigeration NEWS summed up the
outcome of the Montreal Protocol
Amendment Meeting on ozone depletion,
“Montreal Protocol meeting retains
schedule on HCFC’s.” The article quoted
Clifford H. (Ted) Rees, Jr., president of the
Air Conditioning and Refrigeration Institute
(ARI), “This reaffirmation of the HCFC
phaseout timetable gives equipment
owners, manufacturers and government
officials certainty they need to assure a
timely and successful transition.”
Mr. Rees’ statements underscore the fact
that regulations are stable and that
owners can be assured of long-term
reaffirmation of the
“ This
HCFC phaseout timetable
gives equipment owners,
manufacturers and
government officials certainty
they need to assure a timely
and successful transition.
”
availability of alternative refrigerants. This is
clearly good news for the HVAC industry.
And, to understand why this is true in the
case of HCFC-123, one only has to
examine the details of the 1995 Vienna
Amendment to which there was no
change during the 1997 Montreal
Amendment Meeting.
U.S. 1989 HCFC Production Data
Compound (ODP)
MM lbs (ODP weighted)
CFC-11
185.42
CFC-12
382.57
CFC-113
177.27
CFC-114
12.58
CFC-115
10.54
CFC Total
708.38
708.38 x 2.8% = 19.83 ODP Units
U.S. 1989 HCFC Production Data
Compound (ODP)
MM lbs (ODP weighted)
HCFC-22
*
HCFC-141b
*
HCFC-142b
*
HCFC Total
14.76
Total
19.83 + 14.76 = 34.59 ODP Units
*Individual breakdown not available from the producers.
Year
1996
2002
2009
2014
2019
2029
2030
Percent of Cap
100
100
65
35
10
.5
0
To put this ODP weighting data into
perspective, consider the 1989 United
States CFC and HCFC production data in
Table 5.
Clifford H. Rees, Jr.
President, ARI
Table 5: U.S. CFC production data.
Table 6: HCFC production allowance
(developed countries).
HCFC Regulations
As a result of the 1995 Vienna
Amendment to the Montreal Protocol, the
phaseout of HCFC’s uses a cap, or limit,
based on an ozone depletion potential
(ODP) unit concept. The base of this cap is
determined via the following formula:
1989 CFC production x ODP x 2.8% +
1989 HCFC production x ODP = total
ODP weighted cap.
Table 7: HCFC production allowance
(U.S. Clean Air Act).
Year
1996
2002
2009
2014
2019
2029
2030
ODP Units
34.59
34.59
22.48
12.11
3.46
0.17
0
Table 8: U.S. Clean Air Act phaseout schedule.
January 1, 1996
Cap at 2.8% of 1989 consumption of
CFC’s plus HCFC
January 1, 2003
HCFC-141b: 0%
January 1, 2010
HCFC-142b: 0%
HCFC-22:
0% (new product)
January 1, 2020
HCFC-22:
0% (service)
HCFC-123:
0% (new product)
January 1, 2030
HCFC-123:
0% (service)
HCFC calculated cap: 1989 CFC (ODP
weighted) = 708.38 MM lbs. 708.38 x
.028 = 19.83 MM lbs. 1989 HCFC (ODP
weighted) = 14.76 MM lbs. Total cap then
equals 19.83 MM lbs. + 14.76 MM lbs. =
34.59 MM lbs. With the total ODP weight
cap as the base, the phaseout schedule in
Table 6 defines the maximum allowable
for all developed countries.
Using the total ODP unit base previously
calculated for the U.S., this phaseout
schedule then converts to pounds of ODP
units per year shown in Table 7. Of special
interest is how much HCFC-123 the onehalf of one percent limit in the years 2020
to 2030 converts to in pounds of
refrigerant.
Allowable quantity of HCFC -123 from
2020 to 2030, if it were all HCFC-123: 0.17
MM lbs. of ODP units ÷ .014 (HCFC-123’s
ODP) = 12.1 million lbs/year of HCFC-123.
(The .077 kilogram/year, referenced in
Figure 13, page 11, can be converted to
pounds by multiplying by 2.2; .077 million
kilograms/year x 2.2 pounds/kilograms =
.17 million lbs/year, the value used in this
example.)
So far we have only discussed the UNEP
regulation for developed countries. What
does this mean, specifically, to countries
like the United States? Here in the U.S.,
the key is to understand how the U.S. EPA
regulations have been changed to comply
with the Vienna and Montreal
Amendments. Table 8 provides the Clean
Air Act Amendment’s phaseout dates,
dates that have not changed since 1992.
Impact Of HCFC Cap
With all of these numbers and phaseout
dates, what does this really mean to the
HVAC industry? Will there be sufficient
volumes of HCFC-22 and HCFC-123
to meet expected demand?
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In answering these questions, it is
important to understand that the U.S. EPA
carefully calculated total HCFC needs and
the agreement will allow the U.S. to make
full and effective use of these important
refrigerants.
of 2020 and 2030. With reclamation and
recovery, HCFC-22 and HCFC-123 are
projected to be available for another 35
and 45 years, respectively; far beyond the
lifetime of the HVAC equipment in which
they are used.
To demonstrate this point, refer to
Figure 13, which overlays the U.S. EPA’s
calculated HCFC usage on top of the
UNEP cap limits. Because the scale is so
small for the year 2020 and beyond, it is
critical to remember that in the years 2020
to 2030 the one-half of one percent cap
would equate to 12.1 million pounds of
HCFC-123. The question then becomes: Is
12.1 million pounds annually enough to
service the HCFC-123 chillers in operation
at the time? Consider the following.
•
Assume every chiller in North America, all
80,000 plus of them, is operating on
HCFC-123.
•
Assume the average size chiller is 500 ton
with the average pounds of refrigeration to
be two pounds/ton.
•
The average charge, per machine, would
then be 1000 pounds. Result: The total
installed charge would be 80,000 chillers x
1000 pounds/chiller or 80,000,000 pounds.
•
Now assume a total loss rate of 0.5
percent (the field tested and proven loss
rate of Trane “near zero” refrigerant
emission Earth•Wise™ CenTraVac® chillers).
•
Then, the annual service requirement
would be 80,000,000 pounds x 0.5 percent
leakage rate = 400,000 pounds per year.
In developing world countries, HCFC’s are
not scheduled for phase out until 2040;
again sending owners the message that
they can move to alternative refrigerants
and be assured they will be available
throughout and beyond the life of the
equipment in which they are used.
The bottom line, as demonstrated by
these calculations, is that over 30 times
the necessary volume needed for service
is available, even if every chiller in North
America were an HCFC-123 chiller. And,
the Vienna and Montreal Agreements
makes this more true than ever before in
that it reserved the HCFC production from
2020 to 2030 solely for use in air
conditioning and refrigeration applications.
Figure 13: Weighted U.S. HCFC use and Montreal Protocol HCFC consumption cap.
What Is The Status Of Global
Warming Regulations And How
Will It Affect Our Industry?
The headline of a December 22, 1997,
issue of the Air Conditioning, Heating and
Refrigeration NEWS provided insight into
both of those questions. The article also
gave details of an agreement that said,
“It (the Kyoto Protocol)... could change the
HVACR industry even more fundamentally
than the Montreal Protocol.”
“...could change the
HVACR industry even more
fundamentally than the
”
Montreal Protocol.
Air Conditioning, Heating and
Refrigeration NEWS
December 22, 1997
Details of the
Kyoto agreement include:
•
More than 160 countries agreed to a
legally binding protocol on December 11,
1997, in Kyoto, Japan.
•
The protocol calls for an average 5.2
percent reduction of greenhouse gas
emissions by the 38 participating
industrialized countries. Emission
reductions of 8, 7, 6 and 6 percent were
agreed to for the European Union, the
U.S., Japan and Canada, respectively.
These targets are to be met by the fiveyear emissions average over the years
2008 to 2012 and are compared to the
base year 1990. (Countries can choose to
use 1995 levels for three of the six
regulated gases: PFC’s, SF6 and HFC
gases.)
•
Six gases are covered by this treaty:
carbon dioxide (CO2), nitrous oxide (NOx),
methane (CH4), perfluorocarbon (PFC’s),
sulfur hexafluoride (SF6) and
hydrofluorocarbons (HFC’s).
Clearly there are sufficient quantities of
HCFC-123. But how about HCFC-22?
Figure 13 illustrates that there are
sufficient allowances for HCFC-22 use,
with the understanding that its phaseout
date is 2010 for new equipment and 2020
total production ban.
Further, just as CFC refrigerants are
proving to be available for an additional five
to 10 years, via recovery and reclamation,
HCFC-22 and HCFC-123 will be available
for an estimated five to 10 years after their
respective total production ban phaseouts
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•
The protocol will be opened for signature
for one year from March 16, 1998, to
March 15, 1999, and will enter into force
after it has been ratified by 55 countries
representing 55 percent of the total 1990
emissions for developing countries.
•
Currently, developing countries are not
covered by this treaty but will be the focus
of future meetings of the parties.
What impact will this treaty have on
industry, including HVAC? Again, we
believe the headline of the December 22,
1997, NEWS article said it best.
This focus on highest efficiency and
lowest emissions is precisely why Trane
has focused on using the technologies
that allow the design and manufacture of
the Earth•Wise CenTraVac, which is
literally the world’s most efficient, lowest
total refrigerant emissions machine. To
substantiate the efficiency claim, one only
has to ask the various manufacturers for
ARI certified selections at both full and
part-load to prove it.
Is it wise to invest in this efficiency?
Owners are encouraged to invest in
what’s called “no regrets” opportunities;
investments that are good for both
business and for the environment. And
further, while no one can foresee the
future, investments in efficiency are
starting to be seen as insurance;
insurance against potentially substantial
increases in the cost of fuels.
True, seven or eight percent doesn’t seem
like a tremendous reduction; thus, one
might assume it should not be hard to
achieve. Be careful! Those reductions are
from 1990 levels. In the U.S., for example,
Figure 14 shows the full extent of the
reduction required and the various major
market segments that are impacted.
Figure 14
Global Warming:
Higher Energy Costs?
What makes you think that the global
warming threat will bring about higher
energy costs? It already has. Denmark,
the Netherlands, Norway, Sweden and
Finland have already enacted carbon taxes
ranging from $1.20 to $24.20 per ton of
carbon.
A recent U.S. Department of Energy study
concluded that, in order for the U.S. to
return to 1990 emissions levels by 2010,
an “...aggressive program of targeted
research and development would be
required, along with the equivalent of a
$50 tax on each metric ton of carbon.”
It is not unreasonable to believe a primary
market driver will increasingly be efficiency.
How Do We Evaluate The
Combined Effects Of Ozone
Depletion And Global
Warming?
The international community moved
swiftly when it recognized the magnitude
of ozone depletion being caused by CFC’s.
More recently we learned of the threat of
global warming and saw HFC’s included
on the list of controlled gases. Now the
questions become:
•
How should one evaluate the combined or
total environmental impact of alternative
refrigerants?
•
How will this affect our choices of
refrigerants in the future?
These critical questions are being raised
by the scientific and regulatory
communities. In a recent article in
Science magazine for example, Professor
Donald Wuebbles, a leading atmospheric
scientist, and James M. Calm, renowned
industry consultant, built a scientificallybased case that the use of HCFC-123 in
chillers would have negligible impact on
ozone depletion. Further that, because of
its inherent higher efficiency which in turn
offers the opportunity to reduce utility
generated greenhouse gas emissions,
HCFC-123’s phaseout date should be
carefully examined. The article states,
“Phaseout serves no purpose for
compounds that have indiscernible impact
on the ozone...” and “Chemicals that
combine short atmospheric lifetimes with
the potential for energy savings, as shown
for HCFC-123, offer benefits that
outweigh the consequences of very low
ODP and GWP.”
revision to the Montreal
“...a
Protocol to allow continued
use of HCFC-123 in closed
refrigeration systems would
have negligible effects
...on chlorine loading.
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”
Dr. Donald J. Wuebbles
James M. Calm
Science Magizine
November 1997
“
It is probable that HCFC-123
and several other CFC
replacements would have
survived the ban if the global
warming regulations had been
implemented before the ones
for ozone.
Figure 15: Chiller emissions of
HCFC-123 have virtually no impact
on atmospheric chlorine levels.
“..indiscriminate elimination
of classes of compounds, without
regard to offsetting benefits for
those of low concern, may force
less desirable compromises.
R-123 is a clear example.
”
”
are many other
“ There
chemicals that also have
special uses, small impacts,
and where the replacements
for them would cause other
problems. In such cases, it
might make more sense to
consider current policy and
allow the continued use of
some chemicals.
”
Dr. Donald J. Wuebbles
James M. Calm
Science Magizine
November 1997
The question of whether the HCFC-123
phaseout date should be considered was
raised by Dr. Steven O. Anderson, director
for the U.S. EPA, in a September 1997
ASHRAE Journal article when he
stated “...it may become appropriate
to ask whether the environment can
best be protected by reconsidering the
phaseout of HCFC-123. HCFC-123 appears
to have a technical advantage in energy
efficiency and, because it has a low
atmospheric pressure, it can be virtually
contained and recycled indefinitely.”
Dr. David A. Didion
James M. Calm
Trade-offs in Refrigerant Selections:
Past, Present, and Future
In Figure 15, the fact that the yellow
triangles (representing no HCFC-123 phase
out in centrifugal chillers) are directly on
top of the red circles (representing
complete phase out of HCFC-123 in
centrifugal chillers) demonstrates the lack
of any measurable effect by HCFC-123 on
the stratospheric chlorine content.
Also in support of continued use of
HCFC-123, Dr. Sherwood Rowland, Nobel
Prize winning scientist and 1974 founder of
the ozone depletion theory, said in a 1993
speech before 600 ASHRAE members:
“I do have the view that the Montreal
Protocol is working very well, but could
perhaps be improved by allowing the use
for an extended time of HCFCs with short
atmospheric lifetimes such as HCFC-123.”
“...I’ve always felt that there are some
HCFCs that have lifetimes of on the order
of one to two years and there are others
that have lifetimes of 20 to 25 years ...
“...So, I am certainly in favor that HCFCs
should be divided according to their
lifetimes, and the [HCFC]-123, for
instance, has a short lifetime. I don’t see
the sense in including it in with the very
long lifetime molecules, because most of
it is not going to make it to the
stratosphere.”
“...If the world’s governments had asked
me for my advice, I would have divided
(chlorine-containing compounds)
somewhere along the line of lifetimes
shorter than five years. I would put them
in different categories and not be worried
about them for the present time.”
A similar message was heard at the
October 1997 NIST Conference. The
presentation paper titled “Tradeoffs
In Refrigerant Selections: Past,
Present, and Future,” written by Dr.
David Didion of NIST, an individual
internationally recognized for his
research in refrigerants and heat
transfer, and James M. Calm.
It is not just recently that the question
of balancing ozone depletion and global
warming has been raised. As early as
1990, the EPA published a report
showing that as long as refrigerant
emissions were below seven percent,
use of HCFC-123 in centrifugal chiller
applications would have virtually no impact
on the stratospheric chlorine content.
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Table 8 provides a list of atmospheric
lifetimes, ODP’s and GWP’s of the
alternative refrigerants.
U.S. EPA Support
One of the major reasons the U.S. EPA
has supported HCFC-123 and, in fact,
uses it in their headquarters building in
Washington, DC, is because it offers an
excellent balance between all three major
environment issues: Ozone depletion.
Direct-effect global warming potential.
And energy efficiency. (Figure 16.)
Further, it offers a technology where
refrigerant emissions can be reduced to
near zero.
Table 8: U.S. EPA supports HCFC-123
because of its balance of critical environmental factors.
Atmospheric Life
Ozone Depletion
(Years)
Potential
HCFC-123
␣ 1.4
0.014
HCFC-22
12.1
0.04
HFC-134a
14.6
0.0
Global Warming
Potential
90
1500
1300
Figure 17: Galaxy vs. solar system phase.
To underscore this point, Figure 17 is one
of the charts used by a U.S. EPA
spokesperson at a CFC conference. The
point made was that it was originally
chemicals such as CFC-11 and CFC-12
that were the targets. That was a galaxy
approach. In the solar system phase,
where the issue is today, if 0/0 on both
axes is the most environmentally friendly,
it’s easy to see why chemicals such as
HCFC-123, HFC-152a, HFC-32 and HFC134a are being looked at favorably.
The Future Is In the Balance
Does this mean that HCFC-123 is the only
alternative refrigerant of the future? While
HCFC-123 is the most balanced
alternative refrigerant, it is not the only
alternative refrigerant of the future. Today’s
owners and system designers have good
choices:
•
HCFC-123 for low-pressure machines that
have run in the past on CFC-11.
•
HFC-134a for medium-pressure machines
that have been using CFC-12 or 500.
•
HCFC-22 continues to be a good choice
for high-pressure applications.
Figure 16: HCFC-123 is the most
environmentally balanced alternative
refrigerant.
Trane believes it is time for the industry to
stop the infighting that has characterized
the CFC free issue to date and caused
confusion and skepticism among building
owners. Clearly, while this publication
focuses on HCFC-123, the message is
that all alternative refrigerants are
acceptable; a position actively supported
by the U.S. EPA in a technology brief titled
Choosing An Optimal Chiller In The Face
Of A CFC Phaseout. “The key point is this:
building owners should not choose chillers
based solely on one criteria - for instance
ozone depletion potential or lowest first
cost. This is an arbitrary decision that is not
necessarily the best for the overall
environment, and may also lead to
adverse long term economic
consequences. The optimal choice is to
consider all alternatives as acceptable,
viable alternatives, and to choose those
that best meet the criteria and produce
the highest return on investment.”
Understanding that, we would caution
owners, engineers and contractors not to
miss the forest for the trees. In the rush to
make refrigerant decisions, we must not
overlook the basics that have always
played an important role in the selection of
large water chillers. Chiller purchase
decisions should be based on life-cycle
cost plus the criteria that has always been
used:
•
Reliability.
•
Efficiency.
•
Availability of local service and parts.
•
Sound.
A chiller represents a major purchase
decision. Because of its environmental
balance, HCFC-123 is the right alternative
refrigerant for low-pressure technology.
More importantly, the Trane CenTraVac
centrifugal chiller is the right machine. Of
the 46,000 Trane machines built over the
last 50 years, at the start of the CFC-free
transition over 92 percent were still running.
A track record unmatched in the industry.
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What Is The Future Of
So-Called “Third Generation”
Refrigerants?
Until now, this publication has addressed
the second generation alternative
refrigerants in the marketplace. However,
we are frequently asked, “When will we
see the third generation alternatives?”
Table 10 is helpful in understanding the
traditional refrigerants, the commercialized
second generation alternatives and
“potential” third generation refrigerants. It
also raises a series of questions.
1
Will HFC-245ca and/or HFC-245fa replace
HCFC-123 and will HFC-152a replace
HFC-134a? If so, when?
2
Is HCFC-22 still a viable, high pressure
alternative refrigerant?
3
What are refrigerants 407C and 410A and
what kind of nomenclature do these
numbers and characters represent?
Will HFC-245ca/HFC-245fa replace
HCFC-123 and will HFC-152a
replace HFC-134a? If so, when?
Table 11 highlights potential “third”
generation alternative refrigerants that
have several interesting physical
properties: HFC-245ca, HFC-245fa and
HFC-152a. As one can see, the advantage
HFC-245ca and HFC-245fa have when
compared to HCFC-123 is an ozone
depletion potential (ODP) of zero vs. .014.
And, the direct-effect global warming
potential (GWP) of HFC-152a is
approximately nine times lower than HFC134a, i.e. 140 vs 1300. So, at least at first
glance, there appears to be an
environmental advantage with these
potential third generation alternatives.
When might we expect to see these
alternatives in the marketplace? While no
one knows the future, the most likely
answer is never. Why? By today’s test
methods, HFC-245ca and HFC-152a are
classified as Class 2 flammable
refrigerants which imposes, via codes and
standards, vessel sizing (tonnage)
restrictions on equipment designs and a
host of equipment room design
requirements. In addition, most chemical
companies, HVAC manufacturers and end
users in the U.S. are not likely to accept
the greater degree of risk associated with
the use of flammable refrigerants. For this
reason, it is very unlikely these
refrigerants will replace the current
second generation alternatives in the
United States. HFC-245fa, on the other
hand, may well be a low-pressure
candidate in higher tonnage applications;
typically 1250 to 2500 tons and above.
Unlike HFC-245ca, it will not be rated as a
flammable refrigerant. However, pressure
characteristics are such that it would
require ASME pressure vessel construction.
Further, in the case of HCFC-123, there is
a question of “in the balance”... does
HFC-245fa offer an environmental
advantage. While HFC-245fa does have
zero level of ODP, its direct effect GWP is
over six times higher than HCFC-123 and
its theoretical cycle efficiency is less than
HCFC-123. Because of the significant
impact that efficiency has on chiller
greenhouse gas emission, this efficiency
difference could result in increased power
plant emissions of CO2, SO2 and NOx
compared to a HCFC-123-based chiller
design.
Therefore all indications are that the
low-pressure and medium-pressure
alternatives that will continue to serve the
HVAC industry for the foreseeable future
will be HCFC-123 and HFC-134a,
respectively.
Is HCFC-22 still a viable, high
pressure alternative refrigerant?
Absolutely! To understand the reasons
behind that answer is to appreciate why
the answer is stated so emphatically.
1
The total production of HCFC-22 is
currently not scheduled for phaseout until
2020, which is more than 20 years away.
And HCFC-22 is expected to be available
for at least five to 10 years after its
phaseout via reclamation and recovery.
When we consider that the vast majority
of HCFC-22 is used in unitary and
residential equipment with a projected life
of 15 to 20 years, we can understand why
we say HCFC-22 continues to be a viable
alternative.
2
It’s true there are some European
countries calling for an accelerated
phaseout of HCFC-22. However, the U.S.
EPA, ASHRAE, ARI, Australia, Japan,
Canada, the vast majority of developing
countries have all called for a stabilizing of
the current phaseout dates to allow for an
effective transition away from CFC
refrigerants; a message underscored by
both the Vienna and Montreal
Agreements.
3
For refrigerant-in-tube designs, like unitary
and residential applications, the industry is
working on developing alternatives. With
over 43 million HCFC-22 units in North
America alone, as these alternatives start
to replace HCFC-22 in refrigerant-in-tube
applications it will be available via
reclamation and recovery for HCFC-22based chillers where a direct replacement,
minimal capacity loss chemical may or
may not be available.
Table 10
Traditional
CFC-11
CFC-12
HCFC-22
Low Pressure
Medium Pressure
High Pressure
Second
Generation
HCFC-123
HFC-134a
HCFC-22
Table 11: Refrigerant environmental properties
Atmospheric
Lifetime
ODP
HCFC-123
1.4
.014
HFC-245ca
7
0
HFC-245fa
8
0
HFC-134a
15
0
HFC-152a
1.5
0
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GWP
90
560
820
1300
140
“Potential”
Third Generation
HFC-245a
HFC-152a
407C/410A
Theoretical
Efficiency
7.43 COP
7.40
7.31
6.94
7.20
What are refrigerants 407C
and 410A and what kind of
nomenclature do these numbers
and characters represent.
In 1991, the Air Conditioning and
Refrigeration Institute (ARI) initiated a
program called the Alternate Refrigerants
Evaluation Program (AREP) to study the
potential alternatives for HCFC-22. As
Table 12 shows, there were 18
alternatives considered; a consideration
that analyzed efficiency, capacity, material
compatibility, flammability and safety.
Currently, there are two leading
candidates to replace HCFC-22 in
refrigerant-in-tube comfort cooling
applications. These refrigerants are not
referred to by this chemical formula but,
instead, by their ASHRAE nomenclature
407C and 410A.
Here is a more detailed look at each of
these two chemicals. 407C is a ternary
zeotropic blend compromised of HFC-32,
HFC-125 and HFC-134a, with mass
compositions of 23, 25 and 52 percent,
respectively. This blend has zero ODP, a
GWP of 1700 and is manufactured under
brand names like DuPont SUVA-9000, ICI
Klea 66 and AlliedSignal Genetron 407C.
Why these particular chemicals and why
this specific mixture ratio? Because the
blend of these three chemicals in the
ratios listed produces a non-flammable
blend that closely mimics the pressure,
capacity and efficiency characteristics of
HCFC-22. How close? As early as 1995,
Trane displayed a four-ton HCFC-22
rooftop unit running on DuPont SUVA9000. The capacity and efficiency were
101 and 97 percent, respectively, of the
unit’s HCFC-22 performance.
And, the good news is that the traditional
seals and gaskets are typically compatible
with this new HFC blend. This means that
the seals, gaskets and hermetic motor will
not have to be replaced, other than for
normal wear or maintenance, when
switching to the 407C alternative
refrigerant.
However, the oil will have to be changed
from the current mineral oil-based
lubricants to polyester-based (POE) oils.
In many current unitary and residential
unit designs, removal of the oil will require
the unsweating of the compressor and
physically turning the compressor upside
down to remove the mineral oil.
Table 12: Possible HCFC-22 replacements.
HFC-134a
R-125/143a [45/55]
Propane (R-290)
R-23/32/134a [1.5/20/78.5]
Ammonia (R-717)
R-23/32/134a [1.5/27/71.5]
R-32/125 [50/50] - 410A
R-23/32/134a [2/29.4/68.6]
R-32/125 [60/40]
R-32/125/134a [10/70/20]
R-32/134a [20/80]
R-32/125/134a [23/25/52] - 407C
R-32/134a [25/75]
R-32/125/1345a [24/16/60]
R-32/134a [30/70]
R-32/125/134a [25/20/55]
R-32/134a [40/60]
R-32/125/134a [30/10/60]
NOTES: Refrigerants are not listed in any particular ranking order.
Compositions are nominal and do not include deviations of charged or circulating compositions from nominal.
All refrigerant components are HFC’s except R-290 and R-717.
Further, here are several examples of why
testing is required, application by
application.
•
In some compressor designs, the
lubrication system took advantage of the
fact that, in the compressor, the mineral
oils foamed a good deal. This foaming,
technically called splash lubrication or
misting, was used to lubricate
components like piston pins.
Unfortunately, the POE-based oils do not
exhibit this foaming action, which means
that selected compressors will have to be
carefully tested and certified to run with
the HFC refrigerants and POE-based oils.
•
407C is a zeotrope. Zeotropic mixtures do
not evaporate at a constant temperature
as do pure fluids. A temperature “glide”
of eight to 10 degrees occurs with 407C.
Evaporator designs need to be able to
accommodate this difference. For
example, water-source heat pumps would
have to be designed to accommodate this
glide without freezing water in the
evaporator.
•
Superheat and subcooling sensors may
need to be changed to accommodate
different leaving conditions from the
evaporator and condenser. Inadequate
subcooling can occur due to this glide in
the condenser. Unstable expansion valve
operation can also occur in such cases.
•
Condenser fan staging settings for aircooled machines need to be changed
(compared to nominal HCFC-22 settings)
to adjust for the different temperatures
and pressures in the condensers due to
glide.
•
Air-to-air heat pumps will have different
frost and defrost patterns due to glide.
Defrost cycles must be carefully tested.
New defrost sensor location and defrost
logic change is needed in most cases.
These are examples of why, while there
are good alternatives, testing will take
time; time afforded by the current
phaseout schedule for HCFC-22, time to
ensure tomorrow’s products are as
reliable or even more so than today’s
products.
410A is a binary, near azeotropic blend of
HFC-32 and 125 with a 50/50 mass ratio.
An example of 410A is sold commercially
by AlliedSignal under the brand name AZ
20 or DuPont’s brand name SUVA 9100.
This blend operates at significantly higher
pressures than HCFC-22; approximately
50 percent higher. Condensing pressure
at 100 F for HCFC-22 is 196 psi and 410A
is 336 psi. Therefore, it certainly is not a
direct replacement for existing HCFC-22
units.
Then why is it being considered as a
future alternative for HCFC-22 products?
The major reason is because it functions
as a near azeotrope, minimizing the
potential for fractionation. An additional
benefit is that units may be made smaller
because of the higher pressure. However,
the cost advantage of the smaller unit will
be somewhat offset by the need for
stronger, and potentially thicker, materials
in some parts of the unit. Further, the
industry will not only have to totally
redesign the products. It will have to
retool factories to build the new designs; a
task that represents millions and millions
of dollars of investments.
So which one will win out: 407C or 410A?
And in what tonnage sizes?
It is unlikely that there will be one solution
for all applications. Rather, both will have
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their appropriate applications; potentially,
one for new equipment (410A) and one for
replacement applications (407C). While
progress is being made, it will be several
years before equipment with these
chemicals will be commonly available in
the marketplace and service technicians
are trained in their use; once again
stressing the importance of the continued
availability of HCFC-22 under the future
Montreal Protocol Amendments.
What will be a likely alternative refrigerant
for HCFC-22 for non-in-tube applications
such as flooded evaporators?
It appears that because of concern over
fractionation, 407C will likely not be the
alternative refrigerant of choice for flooded
evaporator designs. Instead, the nod will
go to HFC-134a even though, without
redesign, the capacity losses would
typically be in the 25-33 percent range.
With an optimized redesign, the industry
can minimize this impact on the ultimate
cost/performance of the equipment.
Further, extensive testing is and will
continue to be done to determine the
efficiency/cost performance potential of
410A in select applications.
Today we do have viable alternatives.
Viable alternatives that will be around
throughout the lifetime of the equipment.
Alternatives that include HCFC-123 for
low-pressure applications, HFC-134a for
medium-pressure applications and HCFC22 for high-pressure applications. And, for
tomorrow’s refrigerant in-tube
applications, 407C or 410A.
What Are The Best Practices
Owners Are Using To Manage
The CFC-Free Transition With
The Least Possible Cash
Outlay?
It’s very clear. The HVAC industry must
work together to effectively manage a
CFC-free transition.
It will take careful planning to meet this
challenge with the least possible capital
outlay.
Regarding this important planning process
for chillers, we see owners in one of four
phases of planning even today, years after
the phaseout of the CFC refrigerants.
•
Ignore
•
Containment
•
Retrofit
•
Replacement
The Ignore Phase
Unfortunately, there are still a number of
owners who are in the ignore phase.
However, let’s be clear. They are not
ignoring the issue. What they are ignoring,
because of uncertainties and a host of
conflicting information and even some
misinformation, is the need to take action.
The number one suggestion is to move to
the containment phase, at a minimum.
The Containment Phase
In the containment phase, there are
certain things owners will have to do;
there are other things they will want to
do. Examples of the “have to do’s”
include:
•
Technicians are no longer allowed to
voluntarily vent CFC, HCFC or HFC
refrigerants.
•
Service technicians must receive the
appropriate training and must be certified.
•
Appropriate refrigerant purchase and use
records must be kept. To aid in this
record-keeping effort, low-cost,
computerized refrigerant management
programs are available from Trane as well
as several other companies.
If these are examples of the “have to
do’s,” then an excellent example of “want
to do” is to replace older purge systems
with new high-efficiency purge systems
and to implement the state-of-the-art
containment ideas found in ASHRAE
Guideline 3-1996.
At a minimum, today’s owners need to be
in the containment phase.
Each and every one of these alternatives
will play a major role in one of the most
important and difficult challenges this
industry has faced: The transition away
from CFC refrigerants.
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The Retrofit/Replacement Phase
Clearly this is an either/or phase. Owners
who advance to these phases will either
choose to convert their machines to the
alternative refrigerants or to replace their
machines with chillers designed to use
CFC-free alternatives. It is in this phase
where some of the toughest decisions
exist. Why? Because it is in this phase that
the major expenditures are incurred.
Hence, the need for careful evaluation and
analysis of the options.
The evaluation process frequently starts
with categorizing the machines relative to
their age, efficiencies, service and
maintenance expense, ease of
replacement, leakage of refrigerant, etc.
Of these various categories, one of the
most useful is the ability to bracket based
on age. Specifically, it is useful to bracket
the chillers into three age categories: ages
up to 10, 10-20 and 20 years and above.
20 Years And Above: Chillers in this
category are frequently good candidates
for replacement. Why? Because the
chillers may be beginning to reach the end
of their useful life. And, new chillers are
much more efficient than the chillers of 20
to 30 years ago. For example, a late 1970’s
version of water-cooled centrifugal chillers
would have had efficiencies in the range
of 0.7 - 0.9 kW/ton. Today’s water-cooled
centrifugals can boast of efficiencies in the
range of .48 - .60 kW/ton or better at ARI
rated conditions.
Even in a typical office building application,
where operating hours are much less than
a hospital or process cooling application,
this difference in efficiency can result in a
three-year payback or less. This is
extremely advantageous because, even
with a three-year payback, the entire
changeout chiller installation can be
financed and the monthly interest and
principal payments can be less than the
monthly energy savings. Therefore, from
day one, the owner will experience a
positive cashflow. Obviously a positive
cashflow alternative is very attractive for
the private sector. And it also makes
sense for public sector installations.
Up To 10 Years of Age: The chillers in this
category are typically good candidates for
retrofit. Because these machines are
newer, they typically reflect the improved
efficiencies of today’s designs. In addition,
these machines inherently have much of
their useful life remaining.
Especially in this category, planning can
save capital expenditures. One prime
example of using planning to conserve
capital is to plan to do retrofits at the time
of major overhauls; overhauls that are
recommended by all major chiller
manufacturers every five to 10 years.
Consider the following reasoning. During
an overhaul:
1
The seals and gaskets are changed,
providing an ideal opportunity to replace
the traditional seals and gaskets with ones
that are compatible with both the
traditional and the alternative refrigerants.
2
Normally the motor is analyzed and, in
some cases, sent to a motor rewind shop
to be inspected or rewound. This is an
excellent time to replace hermetic motors
with ones that are compatible with both
the traditional and the alternative
refrigerants.
3
While the machine is open, if required, the
gear/impeller sets can be replaced for
gear-driven machines or the impellers can
be modified for direct-drive machines.
By doing the retrofit at the time of a major
overhaul, owners can realize substantial
savings. Experience shows that owners
can save between $10,000 and $15,000
on the retrofit of a typical 500-ton
hermetic centrifugal, if the retrofit is done
at the time of overhaul. The key planning
advice to owners is to use a computerized
spread sheet or other planning tool to
schedule and budget, year by year, for
future major overhauls. And to incorporate
the retrofit at the time of the overhaul.
10-20 Years Of Age: This category was left
for last because it is frequently the most
difficult age bracket of machines for which
to decide appropriate action. The owner
must choose between the more
expensive, but more efficient,
replacement option and the less
expensive, but less efficient, retrofit
option.
Experience has shown that a valuable first
step in making this difficult choice is to
contact the original equipment
manufacturer (OEM). From chiller records,
the OEM can ascertain the original
performance characteristics and then run
computer programs that will provide the
capacity and efficiency data; not only on
the traditional refrigerant, but on the
alternative refrigerant. In addition,
information can be obtained regarding the
cost of reaching various capacity and
efficiency levels.
Once the cost and efficiency numbers are
known for both the retrofit and the
replacement options, design professionals
can use computerized life-cycle cost
analysis programs to provide information
such as simple payback, internal rate of
returns, cashflow or other valuable
financial data to allow the owner to make
an informed decision.
To put this decisionmaking process into
perspective, a retrofit typically costs 20 to
40 percent of the total installed cost of a
replacement chiller. However, depending
on the efficiency differences, the entire
first-cost difference may be paid back in a
short time period; a time period that can
be determined accurately
and dependably.
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Total Systems
The Message Is Clear
One final message. When owners are
making decisions in the process of
becoming CFC free, they are encouraged
to look at all aspects of the chiller plant
system. This includes items such as the
cooling tower, pumps and controls, and to
examine all options: electric, absorption,
ice storage or a combination of all of
these.
Today there are answers. Today it is
critical to become CFC free and to plan
to improve the overall system efficiency
in the process. The key to the future lies
in products, systems and services that
offer the environmentally balanced
solutions combined with the ability to
deliver the very highest in energy
efficiency with the very lowest in total
emissions.
In the 1990’s, and beyond, focus on
improved energy efficiency and multiple
fuel sources, i.e. hybrid chiller plants, will
become absolutely critical. This message
must be understood and internalized.
Because of the focus on energy in the
process of becoming CFC free, owners
are encouraged to actively search for ways
to improve efficiency by addressing all
aspects of the system rather than
focusing solely on the chillers themselves.
Trane has the expertise and tools to aid in
this system approach.
If you would like additional information on
any aspect of the CFC-free issue and/or
assistance with your planning efforts, we
encourage you to contact your local Trane
commercial sales representative.
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Page 1
Worldwide Applied Systems Group
The Trane Company
North American Group
3600 Pammel Creek Road
La Crosse, WI 54601-7599
www.trane.com
An American Standard Company
Printed on recycled paper as part of
The Trane Company’s recycling program.
Since The Trane Company has a policy of continuous
product improvement, it reserves the right to change
design and specification without notice.
CFC-ARTICLE-1
July 1998
Supersedes CFC-ARTICLE-1 April 1996