TRANSITIONING TO LOW-GWP
• ALTERNATIVES IN UNITARY AIR CONDITIONING
Background
This fact sheet provides current information on low Global Warming Potential (GWP) alternatives for new equipment in unitary air conditioning (AC)
relevant to the Montreal Protocol on Substances that Deplete the Ozone Layer}
The unitary AC sector comprises systems that cool enclosed spaces ranging from single rooms to large exhibition halls. These systems have a typical
lifetime of 15 years and generally fall into four categories:
Small Self-Contained Air Conditioners
• Window-mounted, portable, and through-the-wall
• Capacities of 1-10.5 kW
• Average charge size of 0.7 kg
Non-Ducted or Duct-Free Split Residential
and Commercial Air Conditioners
• Compressor/heat exchanger units installed outside the
space to be cooled/heated
• Capacities of 2-20 kW for a mini split (single evaporater),
4.5-135 kW for a multisplit system
• Charge sizes of 0.5-90 kg
Ducted Split Residential Air Conditioners
• Duct supplies cooled/heated air to each room or zone
3 Used primarily in developed countries, especially in North
America
• Capacities of 5-17.5 kW
• Charge sizes of 1-6 kg
Ducted, Commercial, Split and Packaged Air
Conditioners
2010 HFC Consumption
(Estimates Presented in MMTC02eq.)
Solvents
(1%)
Fire Extinguishing.
(4%)
Aerosols
(5%)
Foams
(11%)
Global HFC Consumption Total: 1,087 MMTC02eq.
Global HFC Consumption Unitary AC: 91 MMTC02eq.
Global Ref/AC Sector Total: 858 MMTC02eq.
Global HFC Consumption Unitary AC: 91 MMTC02eq.
China's Experience
China manufactures half of the world's 50 million mini-split AC systems
annually. It's the largest manufacturer of AC equipment in the developing
world. A significant portion of production is for the export market—China
supplies nearly 85% of the window, wall, and mini-split AC imports to the
United States. While R-22 continues to dominate unitary AC domestically, the
country manufactures both R-22 and R-41OA units. The R-41OA units are in
high demand as exports to developed countries. China has commercialized
room ACs with R-290 and is researching unitary AC products with R-32.
• Mounted on roofs or on the ground adjacent to buildings
• Capacities typically range from 5-420 kW
This equipment accounts for an estimated 87 million metric tons of carbon dioxide equivalent
(MMTC02eq.) or 8% of global HFC consumption in 2010. In the refrigeration/AC sector, unitary
AC accounts for 11 % of consumption. This percentage is expected to increase as the transition
from HCFCs to MFCs matures. An estimated 38% of HFC consumption in the unitary AC sector (35
MMTC02eq.) is in developing countries.
HFC Alternatives and Market Trends
Today, most unitary AC systems use HCFC-22. Since 2000, developed countries have been transitioning
to R-410A and to some extent, R-407C. Most developing countries continue to rely on R-22. Currently,
R-22 represents approximately 85% (1.2 million tons) of refrigerant stocks in existing unitary AC
systems worldwide. Of the units sold today, R-22 accounts for approximately 60%, while R-41 OA and
R-407C account for most of the remainder; propane (R-290) accounts for less than 1 %.
Carbon Dioxide (R-744)
• Research to improve efficiency is underway
• Custom-built applications and demonstration units are available
• Increased use is expected in cool to moderately warm climates
Refrigerant
R-410A
R-22
R-407C
HFO blends
R-32
R-1234ze
R-1234yf
R-290
R-744
GWP
2,088
1,810
1,774
<1 ,032b
675
6
4
3.3
1
ODPa
0
0.055
0
0
0
0
0
0
0
3ODP=ozone depletion potential.
bValue shown is based on HFO blend that mirrors the
composition of R-407C, substituting R-1234yfwith
R-134a.
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R-290
• Performs very similarly to R-22
• Charge size is about 40% of an R-22 unit
• Refrigerant costs less than R-22
• Successfully used in small units with <1 kg of refrigerant:
3 Largest Chinese AC manufacturer has commercialized room AC
units using R-290
3 Portable units have been sold in Europe for years
• Use in low charge units expected to increase globally, but use in more
common applications (e.g., ducted split systems, non-ducted mini- and
multi-splits) will require more time
HFC-32
• Higher capacity and efficiency than R-410A
• Investigated as a replacement for R-22, especially in Japan
HFO-1234yf and HFO-1234ze2
• Research may be underway to identify lower GWP compounds using
these agents
Refrigerant Transition in the Unitary AC End-Use51
'Solid arrows represent alternatives already available in the market for these systems;
dashed arrows indicate those likely to be available in future.
• May be used to replace R-41OA, but would require system redesign
due to lower pressure
• Could be used in the small and medium AC markets over the coming
decades
Challenges and Potential Solutions
Some climate-friendly alternatives in unitary AC equipment face technical challenges, such asflammability and toxicity. Additional research is needed to
identify appropriate substitutes for unitary equipment, particularly given the relatively recent and gradual transition from R-22 to MFCs.
Alternative
Challenges
Potential Solutions
R-290
• High Flammability - Challenges For Use in Equipment
With a High Refrigerant Charge (i.e., >1 kg)
• Safety Code Restrictions
• Liability Concerns
• Safety Devices
• Secondary Refrigerant Loop for Larger R-290 Systems, If Leakage and Performance
Penalties Can Be Avoided
• Leak Testing and Pump Down Circuits
• Standards, Service Procedures, Training and Education
• Engineering Design, Research and Development
R-744
• Acute Toxicity/Safety Risks
• High Operating Pressure
• Low Critical Temperature; Can Lead to Low Efficiency
• Engineering Design
• Training and Education
• Research is Being Conducted to Overcome Safety and Efficiency Barriers
R-32
• Low Flammability
• High Pressure
• Has not been Submitted to EPA's Significant New
Alternatives Policy (SNAP) Program
» Engineering Design - Limited Technical Challenges
»Research and Development
»Regulatory Approval
R-1234yf,
R-1234ze
• Low Flammability
• Relatively Low Pressure That Would Require Significant
System Redesign
»Engineering Design
• Use in a Blend with HFCs to More Closely Match the Performance of R-22 and R-410A
»Research and Development
Future Outlook
Taken together, the suite of known alternative chemicals, new technologies, and better process and handling practices can significantly reduce HFC
consumption in both the near and long term, while simultaneously completing the HCFC phaseout. Although there is much work to do to fully
implement these chemicals, technologies and practices, and some unknowns still remain, the industries currently using HCFCs and HFCs have proven
through the ODS phaseout that they can move quickly to protect the environment.
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References
GTZ-Proklima International. 2009a. "Showcase Production of Hydrocarbon Room Air-Conditioning Systems in China."
GTZ-Proklima International. 2009b. "Gree Electric R290 Air Conditioner." Presented on behalf of Gree by Dr. Volkmar Hasse, GTZ-Proklima International,
at the Joint West Asia and South Asia Network Meeting. May 10,2009. Available online at: http://www.hydrocarbons21.com/files/papers/Gree-
presenattion.ppt
ICF International. 2007. "Assessment of HCFC-Based Air Conditioning Equipment and Emerging Alternative Technologies." Final Report prepared for the
World Bank. September 2007.
International Panel on Climate Change (IPCC). 2007. "Climate Change 2007:The Physical Science Basis." Contribution of Working Group I to the
Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.
Tignor, and H.L. Miller (Eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Available online at:
http://www.ipcc. ch/publications_and_data/ar4/wg1/en/contents.html
International Panel on Climate Change (IPCC)/Technology and Economic Assessment Panel (TEAP). 2005. "Safeguarding the Ozone Layer and the
Global Climate System: Issues Related to Hydrofluorocarbons and Perfluorocarbons." Metz, B., K. Lambert, S. Solomon, S.O.Andersen, 0. Davidson, J.
Pons, D.d. Jager, T. Kestin, M. Manning, and L. Meyer (Eds.). Cambridge University Press, United Kingdom. Available online at:
http://www.ipcc.ch/publications_and_data/publications_and_data_reports_safeguarding_the_ozone_layer.htm
Technology and Economic Assessment Panel (TEAP). 2010. "TEAP 2010 Progress Report. Volume 1: Assessment of HCFCs and Environmentally Sound
Alternatives, Scoping Study on Alternatives to HCFC Refrigerants under High Ambient Temperature Conditions." May 2010. Available online at:
http://www.unep. ch/ozone/Assessment_Panels/TEAP/Reports/TEAP_Reports/teap-2010-progress-report-volume1-May2010.pdf
Technology and Economic Assessment Panel (TEAP). 2009. "Task Force Decision XX/8 Report. Assessment of Alternatives to HCFCs and HFCs and
Update of the TEAP 2005 Supplement Report Data." May 2009. Available online at:
http://www.unep.ch/ozone/Assessment_Panels/TEAP/Reports/TEAP_Reports/teap-may-2009-decisionXX-8-task-force-report.pdf
United Nations Environment Programme (UNEP). 2007. "Study on the Strategy for the Long Term Management of HCFCs in China (Presented by
Germany)." February 19,2007. Available online at: http://www.multilateralfund.org/files/51/51inf3.pdf
United Nations Environment Programme (UNEP). 2003. "Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee-
2002 Assessment." January 2003. Available online at: http://ozone.unep.org/teap/Reports/RTOC/RTOC2002.pdf
United Nations Environment Programme Division of Technology, Industry and Economics (UNEP DTIE). 2010. "Alternatives to HCFCs in the Refrigeration
and Air Conditioning Sector - Practical Guidelines and Case Studies for Equipment Retrofit and Replacement." February 9,2010. Retrieved September
20,2010 from: http://www.unep.fr/ozonaction/topics/hcfc_alternatives.htm
1 The four factsheets in this series covering domestic refrigeration, commercial refrigeration, MVACs, and unitary AC represent
approximately 85% of HFC consumption in the refrigeration/AC sector. The remaining HFC consumption in the refrigeration/AC sector
is from chillers, cold storage, industrial process refrigeration, and refrigerated transport. Any service-related consumption is attributed
to the specific end-use. .
US Environmental Protection Agency
2 HFOs (hydrofluoro-olefins) are unsaturated HFCs. HFO-1234yf refrigerant is commonly referred to as HFC-1234yf or R-1234yf, as it EPA-430-F-10-044 • www.epa.gov • September 2010
is referred to in the remainder of thisfactsheet. HFO-1234ze is commonly referred to as HFC-1234ze or R-1234ze. j^ Printed on 100% recycled/recyclable paperwith a minimum
50% post-consumerwaste using vegetable-based inks.
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