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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