Andy Pearson

8/6/2019 Andy Pearson

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Using Ammonia Effectively Overcoming Obstacles and Maximising Benefits

Dr Andy Pearson

Star Refrigeration



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Introduction – Ammonia: the paradoxes

• The Paradoxes

– Natural or not? – Good or evil?

– Safe or dangerous?



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Using Ammonia Effectively – Presentation Contents

• Introduction

– Reasons for wanting to use ammonia

– Range of possible applications

– Scope of potential advantages

• Overcoming Obstacles

– Toxicity

– Flammability

– Public Image

• Strategy for Success

– Design considerations

– Legislative Framework



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• Introduction





– Toxicity

– Flammability

– Public Image






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Reasons for wanting to use ammonia



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• High Temp Heat Pump

• District Heating

• Process Heating

• Air cooled chiller

• Water cooled chiller • Process chiller

• Ice rink

• Cold Store• Air Blast Freezer

• Spiral Freezer




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A = subcooling

A B

B = condensing

C

C = desuperheating

D

D = oil cooling

E = more subcool

E

Ammonia as a heat pump fluid



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A = subcooling

A B

B = condensing

C

C = desuperheating

D

D = oil cooling

E = more subcool

E

R-134a as a heat pump fluid



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IPLV =3.7

4.0 for 45%

3.4 for 42%

2.6 for 1%

3.7 for

12%

R-134a as a chiller fluid



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Ammonia as a chiller fluid

IPLV =4.6

5.0 for 45%

4.1 for 42%

3.0 for 1%

4.8 for 12%



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• Factory tested

• Guaranteedperformance

• Plug and play

• Good turndown• Compact Design

• Low charge

• Low noise levels• Efficient fans

• Long-life package

Ammonia as a chiller fluid



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• Introduction





– Toxicity

– Flammability

– Public Image






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Overcoming Obstacles - Toxicity

• Toxic effect is related to dose

• Dose for ammonia exposure is a combination:

• Concentration of ammonia in the atmosphere….

• ….and length of time the exposure lasts

• In the short term high doses can be tolerated:• For example a dose of 5000ppm would likely be fatal

after two hours exposure….

• ….but it is not likely to cause any injury whatsoever if

the exposure lasts for less than one minute



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?


8 hour TLV

300ppm

IDLH

700ppm IDLH?1000ppm

IDLH?

15 min TLV

30

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* Henderson and Haggard (1943) cited in AIHA “Hygienic Guide Series” (1971)



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• Accidents occur when the rules are notfollowed, so….

• ….make the rules easier to follow• Do not impose excessive constraints or

restrictions;

• ….too much PPE can cause accidents!

• Have a canister respirator tohand when opening a system

• Wear the respirator when the

ammonia smell is “strong”

• If in doubt, retreat!• Only experts should use

SCBA

Andy Pearson

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