adopting zero-odp
TRANSCRIPT
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Safety Considerations for Adopting zero-ODP
and low-GWP Refrigerants
Ozone2 Climate Technology Road Show and Industry Roundtable
Beijing, China
J ay Kohler
April 12, 2012
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Safety Considerations for Adopting zero-ODP and low-GWP
Refrigerants
Presentation will focus on the safe application of refrigerants to
HVAC&R equipment
I will also address environmental considerations
My presentation will provide an update on some relevant ASHRAEsafety Standards.
This presentation has a US emphasis, but also touches on safety
standards and applications in other regions.
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Considerations for Refrigerant Selection
Characteristics that Manufacturers Consider in the Selection of
Refrigerants:
Performance- Efficiency and Capacity
No Ozone Depleting Potential (ODP)
Lowest Global Warming Potential (GWP) Practical
Affordable for end-users
Available
Can be safely applied Focus of this presentation
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Environmental Considerations
Brief discussion of Global Warming considerations.
GWP is important, but it is not the only consideration. In many
cases, it is not even the most important consideration.
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How Can We Relate Performance to Low GWP?:
5
Safety
Considerations
Cost
Considerations
Total Equivalent
Warming Impact
(TEWI)
Indirect
Effects
DirectEffects
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(TEAP 2010)
How Low is Low GWP?
n Different types of equipment have different
refrigerant requirements based on:
n Maintenance practices
n Equipment life
n Recovery / End of Life
n 95% of global HFC use is currently between 700 and
4000 GWP
n TEAP proposed to classify GWPs by considering Use
Patterns
GWP Classification
GWP >30 Ultra-low-GWP
GWP > 100 Very low-GWP
GWP > 300 Low-GWP
GWP > 1000 Moderate-GWP
GWP > 3000 High-GWP
GWP > 10,000 Very High GWP
GWP > 10,000 Ultra-High GWP
n Application
n Charge size
n Leak rate
Low and High GWP are
relative terms,
applications need to be
treated differently
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Safety Considerations: Flammability and Toxicity of Refrigerants
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ASHRAE Standard 34-2010ASHRAE Standard 15-2010
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Toxicity
Chronic Exposure measures
Class A
No known toxicity at < 400 ppm
Class BEvidence of toxicity at < 400 ppm
Based on PEL or OEL measures
Acute Toxicity
Reflected in the RCL (Refrigerant ConcentrationLimit), which looks at both flammability and
toxicity measures
Designation and Safety Classification of Refrigerants ASHRAE
Standard 34-2010
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Designation and Safety Classification of Refrigerants
ASHRAE Standard 34-2010
A3A3
A2A2
A1A1
B3B3
B2B2
B1B1
lowertoxicity
lowertoxicity
highertoxicity
highertoxicity
refrigerant safety groups
higher
flammability
higher
flammability
lowerflammability
lowerflammability
no flamepropagation
no flamepropagation
Historical classification has included 6 safety groups, with three
flammability groups
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Flammability Classification
Class 1 - No Flame Propagation
Class 2 - LFL > 0.10 kg/m^3
and heat of combustion < 19 MJ/kg
Class 3 - LFL 0.10 kg/m^3
or heat of combustion 19 MJ/kg
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Designation and Safety Classification of Refrigerants
ASHRAE Standard 34-2010
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Designation and Safety Classification of Refrigerants
ASHRAE Standard 34-2010
A3A3
A2A2
A1A1
B3B3
B2B2
B1B1
lowertoxicity
lowertoxicity
highertoxicity
highertoxicity
refrigerant safety groups
higherflammability
higherflammability
lowerflammability
lowerflammability
no flamepropagation
no flamepropagation
Recently added was an optional flammability classification of 2L
A2LA2L B2LB2L new 2Lnew 2Ldifficult to ignite
and sustain
difficult to igniteand sustain
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New 2L flammability classification
Similar to class 2, except for an additional requirement. Refrigerant must have a
maximum burning velocity of10 cm/s (3.9 in./s) when tested at 23.0C (73.4F)
and 101.3 kPa (14.7 psia).
Combustion tests have shown burning velocity to be a significant parameter. As
compared with refrigerants with a higher burning velocity, 2L refrigerants are:
More difficult to ignite
Have a less stable flame
Are less likely to cause a rapid pressure buildup (i.e. explosive event)
The 10 cm/s criterion is not reflective of a sudden change in combustion
behavior, but rather is a convenient condition for differentiating combustion
behavior of lower and higher burning velocity refrigerants
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Designation and Safety Classification of Refrigerants
ASHRAE Standard 34-2010
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Why the interest in 2L refrigerants?
Need for low GWP refrigerants with short atmospheric lifetime
Such refrigerants are less stable than other refrigerants.
Need a balance of stability in refrigeration systems, short atmospheric lifetime,
and flammability characteristics.
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Designation and Safety Classification of Refrigerants
ASHRAE Standard 34-2010
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ASHRAE Standard 15-2010 provides
requirements for the safe design, construction ,
installation, and operation of refrigeration
systems. It is applied to buildings (stationary
applications).
Requirements based on three classifications:
1.Occupancy (Section 4)
2.Refrigeration System (Section 5)
3.Refrigerant (Section 6 & Standard 34)
Safety Standard for Refrigeration Systems ASHRAE Standard 15-2010
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ASHRAE Standard 15-2010 has limitations on the application of flammable and
toxicity class B refrigerants.
Section 7.5.2 Applications for Human Comfort. Group A2, A3, B1, B2, and B3
refrigerants shall not be used in high probability systems for human comfort (with
some exceptions).
Safety Standard for Refrigeration Systems ASHRAE Standard 15-2010
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ASHRAE Standard 15-2010 has additional limitations on the application of
flammable refrigerants including, but not limited to:
1.Restrictions for specific occupancies (Section 7.2)
2.Charge quantity limitations (Section 7.5.1)
3.Special machinery room requirements (Sections 7.4.2, 8.11, and 8.12)
4.Class 3 limitations (Section 7.5.3)
5.Relief valve discharge requirements (9.7.8)
6.Leak test requirements (9.14, 10.1)
Safety Standard for Refrigeration Systems ASHRAE Standard 15-2010
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ASHRAE Standard 15-2010 does not presently have requirements for class 2L
refrigerants. The cognizant committee is evaluating such requirements. An
Advisory Public Review was published in July 2011. Comments were received
and will be taken into consideration for the next Public Review document. The
committee is working towards a version of the standard that incorporates 2L
refrigerants and can be referenced by US building codes.
Safety Standard for Refrigeration Systems ASHRAE Standard 15-2010
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ASHRAE Standard 15-2010 considerations for use of 2L refrigerants include:
Existing Standard 15 structure and classification system, including use of RCL
methodology to limit charge quantities in occupied areas
Existing requirements for ammonia (R-744), which is now a 2L refrigerant and
has a history of application in accordance with the standard Results of analysis and testing of 2L refrigerants. Those results show the
difficulty in igniting and sustaining combustion, particularly in an environment with
moving air.
Need for an ignition source of sufficient energy and temperature
Maximum quantity limitations, which are less restrictive than those for class 2refrigerants
Safety Standard for Refrigeration Systems ASHRAE Standard 15-2010
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ISO 817 - Refrigerants Designation and Safety Classification
n Requirements are similar to those of ASHRAE 34. Undergoing FDIS approval. Includes
2L classification, similar to ASHRAE 34.
UL-1995 - Heating and Cooling Equipment
n
A working group is evaluating changes to incorporate 2L refrigerants
ISO 5149 - Refrigerating systems and heat pumps Safety environmental
requirements
n A WG has been working for several years to update this standard. A FDIS version exists
that includes 2L refrigerants
EN-378 - Refrigerating systems and heat pumps - Safety and environmental
requirements
n Work is ongoing
Other Relevant Standards
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Safety Considerations: When can Flammable Refrigerants Be Used?
Flammable refrigerants will be applied as allowed by safety codes.
Experience in the industrial refrigeration sector as well as early adoption in
northern European commercial AC &R sectors provides experience for the
future.
Safe use in developing countries will require a significant amount of training and
education throughout the supply and value chain. Infrastructure will need to be
created to ensure safety codes and procedures are followed. Until this happens,
HFCs and non-flammable HFO blends will need to remain available.
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Examples of Successful Commercial Applications for Flammable Refrigerants
London Heathrow T5 is cooled by ammonia chillers.
Oslo, Gardamoen, and Copenhagen International Airports are cooled with NH3
District heating systems are being installed in Norway with ammonia heat pumps
Aarhus University Hospital, Skejby in Denmark is cooled and heated by HC chillers and
heat pumps.
Hotel Scandinavia and the connected Aarhus Congress Centre in Aarhus installed NH3chillers in 1996.
McDonalds in Denmark has installed cascade system using HC and CO2 in their
restaurants.
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Natural Refrigerants remain excellent solutions in some very specificapplications:
nAmmonia for refrigeration
n C02 cascaded systems for supermarket refrigerators/freezers
n Propane and isobutane in domestic refrigerators and appliances
n Hydrocarbons in small packaged air-cooled equipment
Energy efficiency of resulting systems must remain at HFC levels or better.
System cost and application cost can be a barrier to adoption.
HC Air-Cooled
Chillers
CO2
When do Natural Refrigerants Make Sense?
Ammonia
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Because of the requirements of safety, efficiency, and cost, synthetic refrigerants
must remain an option in many regions and applications:
n HFCs and Blends of HFOs and HFCs can provide highly efficient non-
flammable solutions for developing regions.
n Large commercial air-conditioning systems with significant charge amounts
n Large refrigeration applications in densely populated areas
Equipment Size and application will dictate types used:
Most economical solution when higher GWPs can be tolerated
When do HFOs and HFCs Refrigerants Make Sense?
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The Influence of Affordability on Adoption: What Role will Installed Cost
Play?
In order to produce a competitive product manufactures must consider the
following cost related to refrigerants:
Cost of refrigerant itself
Cost of an increases in heat exchange surface, compressor modifications, structural
changes needed to meet or exceed capacity or efficiency requirements
The cost of any safety features or controls to ensure safe operation of the machine
The installed cost of any safety features or alarms that ensure safe application to the
built environment
Maintenance and service cost over the life of the equipment
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How does the availability of refrigerant options affect short term
decision making?
Synthetic Refrigerants are used in many other applications than just stationary
HVAC&R equipment. Often the justification for refrigerant manufacturers to bring
a product to market depends on quantities well beyond our demand level.
While the various refrigerant companies have been actively researching new
alternatives, very few, if any are available now in production quantities.
Industries such as mobile AC and the production insulating foams will dictate the
timing and composition of synthetic refrigerants that enter the marketplace in the
future.
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Summary
Manufactures must consider many factors when selecting future refrigerants.
Global Warming concerns must consider broad measures such as TEWI.
Safety codes presently address toxicity and flammability issues.
New refrigerant flammability class of 2L exists in ASHRAE Standard 34.
Safety codes are under revision to address 2L requirements. Those
requirements will be less stringent than those for existing class 2 refrigerants.
As we move toward natural refrigerants and flammable synthetic options,
training, education, and safety codes will be essential for universal adoption.
Synthetic refrigerants serve an important role where efficiency and safety are
a primary concern.
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Questions?