Automotive Engineering - December 2022 - 12

TECHNOLOGY REPORT
HVAC
A new A/C refrigerant joins the global-warming fight
A tri-part blend refrigerant, R-456A, has
been introduced as a service replacement
for the original refrigerant in R-134a automotive
air-conditioning systems. The reaction
likely is: Why would anyone want
this? A blend would seem to raise all
manner of complications; R-134a itself
proved safe and works well, so a changeover
to R-456A might seem pointless.
That once was true. R-134a had been
relatively cheap and it even has even
been used to change over systems from
R-12, which was phased out for environmental
reasons including ozone layer depletion.
But a law enacted last year, the
American Innovation and Manufacturing
(AIM) Act, upset that picture.
The AIM Act sets a 15-year schedule
for a U.S. phaseout of HFCs (hydrofluorocarbon
gasses) to reduce global warming
and the phaseout already has affected
worldwide supplies of R-134a, a
primary HFC application. Europe has a
more aggressive HFC phaseout schedule
and has just begun to use the R456A
blend, because R-134a supplies there are
tight and prices are soaring. The U.S. is
not far behind: R-134a prices have more
than tripled, typically running up to
$400 for a 30-lb. (13.6-kg) tank.
And that's with just the first step in
the U.S. phaseout (10% cut in production,
based on 2011-2013 usage). A 40%
HFC reduction is required within five
years, 70% in 10 years, and finally, 85%
in 15 years (by 2036). Reducing production
is not a matter of just " closing a
spigot, " so being sure to run just ahead
of a regulation can lead to severe shortages
in the phaseout period.
Sub-700 GWP
R-456A is being sold by Koura Global, a
long-established fluorochemical company
previously known as Mexichem and ICI
(for Imperial Chemical Industries), producer
of the refrigerant brand " Klea. "
Koura is being followed to market by a
Honeywell-developed three-part refrigerant
blend. Marketed under the Solstice
brand, Honeywell's product consists of
45% R-134a, 49% R-1234ze (a mildlyflammable
refrigerant in a class of gasses
12 December 2022
Worldwide automotive R-134a systems number in the hundreds of millions, creating a huge market
for a non-HFC substitute.
Pressure-temperature
graph shows how close
are the R-134a and
R-456A curves, which
obviates any concern with
system calibration parts.
called hydrofluoroolefins) and 6% R-32-
another mildly flammable refrigerant that
is added to improve cooling performance.
The fluorochemical industry's supply
approach is to use the R-456A blend as
an R-134a supply extender, by combining
it with R-1234ze, which although mildlyflammable,
has a near-zero global warming
impact. This supply extension originally
led to R-513A, a blend of R-134a
and R-1234yf, another HFO that replaced
R-134a in cars. The R-513A blend was
introduced by Honeywell and Chemours
in 2021 as an R-134a substitute for chillers
and related non-automotive applications
and is widely sold in Europe.
Worldwide, automotive R-134a systems
number in the hundreds of millions. The
refrigerant was used from 1992 until the
2013 introduction of mildly flammable
HFO R-1234yf, with A/C system modifications
to mitigate the flammability risk. So,
a non-HFC automotive substitute for
R-134a service should have a large market.
The R-456A blend is a near-azeotrope,
which means there is minimal separation
of the component gasses
throughout the refrigeration cycle.
As the accompanying pressure-temperature
graph shows, R-456A is very
close to R-134a. Combined with the
near-azeotropic characteristic of the
blend, it's unnecessary to change the
operating calibration parts of the R-134a
system to use R-456A. Unlike the previous
major A/C refrigerant retrofits (R-12
to R-134a), R-456A is a true drop-in.
Paul Weissler
AUTOMOTIVE ENGINEERING
FROM TOP: KIA; KOURA GLOBAL

Automotive Engineering - December 2022

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