ASHRAE Journal - March 2021 - 31

ROUNDTABLE

designed for working pressures
above 15 psig (100 kPa) and carry
ASME certiﬁcation.
R-514A is a blend (75%
R-1336mzzZ/25% R-1130E)
designed to be close to R-123 in
pressures and capacities. Like
R-123 it is a higher toxicity ﬂuid
(ASHRAE " B1 " ), which may limit
its market acceptance. It is primarily used in existing R-123
Ivan Rydkin., Associate
Member ASHRAE,
designs for new equipment
Refrigerants Technical
applications.
Lead, North America, Daikin
Sarah Kim: In addiAmerica, Rochester, N.Y., vice
tion,
I would like to add that
chair of SSPC 147.
R-1233zd(E) has a very low GWP
of 1,1 which makes it suitable as a long-term solution.
With advancement in technology, it is expected that
R-1233zd(E)-based low pressure solutions will replace
some of the medium pressure smaller capacity chillers
due to its superior efﬁciency and the nonﬂammable
nature of the ﬂuid per Standard 34-2019.
Are any of these more optimal solutions than others?
Johnston: R-1233zd(E) has been the refrigerant of
choice for new equipment designs, with multiple manufacturers designing new chillers based on this ﬂuid. The
" A1 " rating, high efﬁciency and single working ﬂuid are
key attributes driving this.
Kujak: All alternatives in this category are acceptable for use in large capacity water cooled chillers.
They are all high efﬁciency and all easy to handle. Even
though a number of these replacements are not designcompatible replacements for R-134a, manufacturers
are announcing their use as primary options to replace
existing R-134a products.
Can any of these alternatives be used to retroﬁt existing R-123
chillers?
Charles Allgood: Yes, R-514A was developed speciﬁcally as a replacement for R-123 in both existing R-123
chillers and new systems similar in design to traditional
R-123 systems.
Kujak: Yes, R-514A is a near design-compatible option
for R-123 designs, and engineered retroﬁts are available.
Any refrigerant retroﬁt requires proper considerations
to the impact on the application and the chiller performance. In the last transition, a large number of R-11
units were retroﬁtted to R-123. R-123 with a GWP of 77 is

already considered a low GWP, so the cost of future R-123
will be unaffected by a GWP based refrigerant allocation
restriction. Thirty years of experience with R-11 shows
that R-123 will be available long into the future beyond
the expected life of the equipment.
Johnston: With proper preparation, it would be possible to use R-514A in an existing R-123 chiller. For example, an oil ﬂush and change is required, and impeller
and/or gear changes may also be needed. It would be
best to consult the chiller manufacturer about the possibilities and performance impacts.
What about using natural refrigerants in large water cooled
chillers?
Kujak: Natural refrigerants like ammonia (R-717) are
seeing incrementally more adoption in this area for
comfort cooling, but its toxicity is limiting its use in large
refrigerant charge systems. Hydrocarbons are not being
adopted in this area because of signiﬁcant safety concerns, and carbon dioxide (R-744) efﬁciency is too low and
its pressure is too high to warrant any consideration.
Johnston: Due to their highly toxic and highly ﬂammable properties, refrigerants such as R-717 or hydrocarbons are not preferred in these types of high charge
size systems, especially when installed outside of industrial settings. Many of these large building chillers are
in use in densely populated urban environments where
the risks of using ammonia are too high, or simply not
allowed by local regulations.
What are potential alternatives for R-134a and what attributes
make these good low GWP alternatives for R-134a?
Allgood: R-513A is the leading nonﬂammable, low
GWP replacement for R-134a in a wide variety of applications including low temperature ice rink chillers,
low-temperature/medium temperature commercial
refrigeration systems (stand-alone, cascade, distributed
architectures) and comfort cooling chillers. Numerous
OEMs have commercialized equipment based on
R-513A. Its similarity to R-134a in terms of capacity, efﬁciency and pressures with ~50% reduction in GWP have
also made it the preferred choice when retroﬁtting an
existing R-134a system in the ﬁeld.
Kujak: The HFC GWP regulations are a phasedown
process rather than a phaseout process that was required
during the ozone depletion regulation. As such, the regulation realizes that as refrigerant technology matures,
interim moderate GWP refrigerants may be required as
transitional ﬂuids to enable the phasedown process and
MARCH 2021

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