Adopting Zero-ODP

8/13/2019 Adopting Zero-ODP

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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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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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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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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).



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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)



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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.



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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



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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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