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TRANSCRIPT
Component technologies for low GWP refrigerants in Air Conditioning
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Torben Funder-Kristensen, Head of Public Industry Affairs
Content
• Issues in Future AC systems
• Risk Awareness
• Safety Standards
• Improving Energy Efficiency
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• Heat Exchangers
• Controls
• Compressors • Scroll – R32 – R290• TurboCor – R1234ze
• Conclusion
Issues in future Air Conditioning systems
� The need for Air conditioning will follow the growth in the developing countries
� The increase in the market will predominantly be in very hot climates
GWP
R410a
R404a
R12
R11
HFC
CFC
HCFC
HFO
Natural
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predominantly be in very hot climates
� Energy supply will be a factor to observe
� Keep up long term performance
� Demand for peak load reduction
� Safety precautions using low GWP refrigerants to be embedded in service procedures and behaviour
TEWI
R134a
R744(CO2)
R1234(yf, ez)
R32
R717 (ammonia)
R718(water)
R22flammable
R152a
Scenario
R290(propane)
44
33
22
11
Actual risklogic line
“New” RefrigerantUser experience
Industry
Actual risklogic line
“New” RefrigerantUser experience
Industry
Risk awareness
Make Standard for framing Product activities with flammable refrigerants
Perform process of Risk Assessment & conclude on probability of Scenarios
Propose scenarios based on application
experience
Establish knowledge on Standards &
Legislation
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Perceived risk
Mature Refrigerants
Industry Competence
Perceived risk
Mature Refrigerants
Industry Competence
• What level of risk is acceptable ?
• Orderly risk handling to ensure safety in all aspects
Adverse and get acceptance of
Insurance Company
Top Management approval
Product manager deployment
Safety Standards
ISO5149 does not support flammable refrigerants
ISO 5149 supports flammable refrigerant (like HC) including 2L flammability (R32 and HFO’s)International
International for large systems
Safe systems can be built by ensuring that systems design and service follow international standards:
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2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
EN 378 supports flammable refrigerants EN 378 aligned with ISO 5149 on 2L flammability
flammable refrigerants including 2L flammability (R32 and HFO’s)
Chinese national standard does not support flammable refrigerants
Chinese national standard copies the new ISO5149 with full support of flammable refrigerants
IEC 60335-2-40 supports some flammable refrigerants
IEC 60335-2-40 aligned with ISO 5149 on 2L flammability
UL 60335-2-40 does not support flammable refrigerants
Chinese A/C & HP, no support of flammables
Chinese national standard for A/C & HP supports flammable refrigerants, but no special support of 2L
International and Regional standards
Selected National standards
large systems
EU for large systems
International for A/C and HP
China for A/C and HP
China for large systems
UL 60335-2-40 support 2L flammability, but not HC
US for A/C and HP
Improving Energy Efficiency
BAT cycle
Condenser
Compressor
� Each Component must be optimized to obtain a BAT (Best Available Technology) cycle
� Heat Exchangers to
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Theoretical Optimal Cycle
Evaporator
Injectio
n
� Heat Exchangers to have more efficient heat transfer with the help of Injection devices and optimized fans
� Compressor to use efficient motors and designed to run with minimum internal losses
Consequences using GWP refrigerants
Low GWP refrigerants are theoretically as good as any high GWP HFC
In reality flammability will put restrictions to demands for systems and
Real cycle
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restrictions to demands for systems and components
• Higher classification grades (i.e. PED)
• Limits to charge sizes (to obey EN378)
Especially the Heat exchangers are key to reduction of charge sizes.
Theoretical Optimal Cycle
The heat exchanger challenge
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Drive Technology ToMinimize Refrigerant Charge
Refrigerant to air HEX
Finn and Tube heat exchangershas been substituted by Micro Channel heat exchangers
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• Reduce charge up to 70%
• Improve efficiency
BPHE - Braze Plate Heat Exchangers
Traditional designs can still bechallenged to
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challenged to
• Reduce charge up to 30 %
• Improve efficiency
Injection & other controls
� TXVs are suitable for all low GWP refrigerants as R290, R32
� EXVs are suitable too but need to be evaluated with regard to ATEX
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evaluated with regard to ATEX
� Internal motors are not a problem
� External coil – ATEX approval
� Injection components can be found on the market where legislation allows for usage
Impact of refrigerant on compressor design
R290 compressor vs R22
� R290 is in the A3 classification with high
flammability, which means the R290
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compressor needs to meet ATEX
requirements.
� As R290 is a strong solvent, a new lubricant
needs to be developed.
Impact of refrigerant on compressor design
R32 compressor vs R22
� High pressure involve redesign of major mechanical
parts
� High volumetric cooling capacity leads to smaller
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swept volume
� Lower mass flow rate leads to increased motor
cooling demand.
� Discharge temperature needs to be controlled from
the compressor side or the system side.
� Lubrication & Miscibility , a POE oil (instead of
Mineral) need to be used
Scroll Compressor R32Based on R410A compressor platform
R32 impacts on compressor design are
� Cooling capacity + 7%
� Drive torque +9%
Involute pressure ratio Reduce volumetric
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� Involute pressure ratio Reduce volumetric
ratio
=> Keep same displacement
� Lower mass flow rate -30%
=>New gas path design
� Highest Discharge temperature+22%
=> Use liquid injection
Centrifugal Compressors
• Large systems
• Needs heavy molecules
• R134a was the choice for decades
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• R134a was the choice for decades
• R1234ze has shown to be a very good substitution for R134a
• R1234ze can be run in oil free systems
Conclusion
Low GWP refrigerants become viable for air conditioning. Components are or will soon be available.
The hazards associated with low GWP refrigerants are being mitigated in standards and legislation –however – consistency must be made to align
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however – consistency must be made to align system and components standards with building safety standards.
Education of service sector must have a high priority to avoid accidents
R290 is an obvious global choice for smaller systems. R32 can for safety reasons substitute on larger systems. R1234ze has a high potential for becoming a future refrigerant for large chillersystems.
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