DALLAS — While much of the buzz at the AHR Expo was on dwindling supplies of
new HCFC-22, reclamation of that refrigerant, and use of alternative HFCs in
retrofits, a number of conversations centered on alternatives beyond familiar
HFCs. Even with the regulatory landscape unclear, the high global warming
potential (GWP) of some HFCs was causing a stir on the show floor.
Low-GWP HFCs
While HFC-410A was firmly encamped as the refrigerant of choice for air
conditioning in a large number of applications, its high GWP was turning
attention in Dallas to use of HFC-32 as a stand-alone refrigerant. HFC-410A,
which was introduced to the industry more than a decade ago as an alternative to
R-22 in new equipment, carries a high GWP. R-32 has a much lower GWP (675 vs.
2088). This is a topic that has been in the industry for a number of years,
since it first surfaced as a high-profile topic in 2010 at industry conferences
hosted by Purdue University.
Danfoss furthered this notion at its AHR Expo booth, where it displayed its
SG scroll compressor with the signage: “Get ready for Green Solutions with
R-32.”
HFOs on Display
HFO refrigerants are widely recognized as the next generation of
refrigerants. The alternative garnered its fair share of attention at the expo
as well.
On the show floor, Honeywell was issuing a statement about its HFO
refrigerant 1234ze which it markets as Solstice L-41. The manufacturer compared
its refrigerant, stating that their refrigerant offers “significant advantages
over another (R-410A) alternative, R-32, which has a higher GWP and limitations
related to high-discharge temperatures, which can affect performance and
durability in hot climates, and may also require new lubricants.”
Honeywell boasted that Solstice L-41 offers a 75 percent reduction in GWP
compared to R-410A and is intended to replace R-410A in residential and light
commercial air conditioning and heat pump applications. In addition to its lower
GWP, Solstice L-41 offers excellent energy efficiency, is cost effective, and
can be used in existing equipment designs with minimal changes.
“Honeywell has been working closely with leading equipment manufacturers to
optimize Solstice L-41 to meet the demanding requirements of both stationary air
conditioning and heat pump applications across a broad range of operating
conditions,” said Tom Morris, director of commercial development for Honeywell
Fluorine Products. “Solstice L-41 will allow these manufacturers to offer more
environmentally friendly air conditioning and heat pump systems to help address
climate change.”
Solstice L-41 is based on Honeywell’s HFO-1234ze technology, which was “first
introduced in 2008 and has since been proven and commercialized for chillers,
insulating-foam, and aerosol applications. A new HFO-1234ze manufacturing plant
is currently under construction to meet the needs of equipment
manufacturers.”
Even with its involvement with R-32 in some applications, Danfoss was waving
the HFO flag. The company used a press conference to announce its involvement
with HFO-1234ze in its Turbocor line and the commercialization of TG310
compressors, which were released as a developmental prototype in early 2012. The
company said the compressors “utilize the ultra-low GWP, zero ozone depletion
potential (ODP) refrigerant HFO-1234ze.”
Safety First
As the HFO sector evolves it is becoming clear that there are HFOs with A1
(nonflammable) safety ratings and those that have A2L (slightly flammable)
safety ratings. A1s generally carry higher GWPs than A2Ls. This means the sector
will have to sort itself out. If regulations set especially low GWP maximums,
only A2Ls would be allowed to establish a beachhead; which would require UL
certification, as well as building code modifications, for the installation of
such equipment in certain portions of the country.
One HFO topic that appears to be sorting itself out is in the automotive
sector. After automaker Daimler expressed some safety concerns over the use of
HFO-1234yf in vehicle air conditioners last fall, General Motors issued a
statement at the time of the expo pledging to move ahead with the use of that
HFO in its vehicles — saying that in all its testing, the refrigerant proved
safe and effective.
HCs and CO2
A number of manufacturers showed equipment for natural refrigerants such as
HCs and especially CO
2 at the expo.
During a Danfoss press briefing, Scott Martin, director of sustainable
technologies, Hill Phoenix, spoke about CO
2 developments that his
company has been doing in conjunction with Danfoss. He said that his company’s
systems that utilize CO
2 technology offer several distinct advantages
over traditional DX-refrigeration systems. “These CO
2 sub-critical
systems deliver superior refrigeration performance with enhanced sustainability,
reduced refrigerant-charge requirements, and greatly reduced refrigerant-leak
rates. Simply, they are the most energy-efficient and environmentally friendly
refrigeration systems available in the industry today.”
He also noted advances in CO
2 in transcritical-application use of
which are growing in North America. That was reinforced on the show floor at the
Bitzer booth where a transcritical-CO
2 compressor was displayed.
The editors of the European-based online publication R744.com also walked the
floor at AHR and provided a viewpoint for its global readership regarding the
future direction of CO
2 use in the United States.
“The pure number of booths displaying CO
2 refrigerant components
and systems has not significantly increased from last year’s trade show.
However, the showcase of breakthrough innovations, prototypes, and optimized
product lines in R-744 (CO
2) compressors, heat pumps, or air
conditioners, as well as commercialization announcements expected for the next
12 months are all solid indicators that the U.S. market is getting serious about
R-744.”