Using Ammonia Effectively Overcoming Obstacles and Maximising Benefits

1. Using Ammonia EffectivelyOvercoming Obstacles and Maximising Benefits Dr Andy Pearson Star Refrigeration

2. Introduction – Ammonia: the paradoxes • The Paradoxes • Natural or not? • Good or evil? • Safe or dangerous?

3. 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

4. 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

5. Reasons for wanting to use ammonia

6. Reasons for wanting to use ammonia

7. Reasons for wanting to use ammonia • 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

8. A B C D E A = subcooling B = condensing C = desuperheating D = oil cooling E = more subcool Ammonia as a heat pump fluid

9. A B C D E A = subcooling B = condensing C = desuperheating D = oil cooling E = more subcool R-134a as a heat pump fluid

10. R-134a as a chiller fluid 4.0 for 45% 3.7 for 12% 3.4 for 42% 2.6 for 1% IPLV =3.7

11. Ammonia as a chiller fluid 5.0 for 45% 4.8 for 12% 4.1 for 42% 3.0 for 1% IPLV =4.6

12. Ammonia as a chiller fluid • Factory tested • Guaranteed performance • Plug and play • Good turndown • Compact Design • Low charge • Low noise levels • Efficient fans • Long-life package

13. 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

14. 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

15. Overcoming Obstacles - Toxicity 8 hour TLV ? 300ppm IDLH 30 15 min TLV 15 700ppm IDLH? 1000ppm IDLH? * Henderson and Haggard (1943) cited in AIHA “Hygienic Guide Series” (1971)

16. Overcoming Obstacles - Toxicity • Accidents occur when the rules are not followed, so…. • ….make the rules easier to follow • Do not impose excessive constraints or restrictions; • ….too much PPE can cause accidents! • Have a canister respirator to hand when opening a system • Wear the respirator when the ammonia smell is “strong” • If in doubt, retreat! • Only experts should use SCBA

17. Flammability: detonation, explosion or conflagration? • There are two main considerations when discussing flammability: • How easy is the gas to ignite? • How much damage does it do when it burns? • These are assessed in EN378 by considering: • Lower flammable limit • Heat of Combustion LFL > 3.5 v/v HOC (MJ/kg) HOC < 19MJ/kg 20MJ/kg Class 2 0MJ/kg 0 5 10 15 20 25 30 LFL (ppm v/v)

18. Flammability: detonation, explosion or conflagration? • Some new factors are being considered: • Burning velocity • Minimum Ignition Energy • These are not currently assessed in EN378 • MIE is an alternative to LFL (how easy…?) • BV is an alternative to HOC (how damaging…?)

19. Flammability: detonation, explosion or conflagration? Key Questions: • Does this change do anything to make systems safer? • Are these new parameters easier to measure? • Do we need more than 2 classes: • Non-flammable • Flammable • Do we need more than 3 classes: • Non-flammable • Mildly flammable • Highly flammable

20. Overcoming Obstacles - Public Image (1) • 10 August: Fatal accident on Malaysian trawler kills six workers, five injured. Ammonia in refrigeration system is blamed in the press

22. Overcoming Obstacles - Public Image (1) • 10 August: Fatal accident on Malaysian trawler kills six workers, five injured. Ammonia in refrigeration system is blamed in the press • 18 August: Further investigation suggests that ammonia was not to blame, but the workers were overcome by hydrogen sulphide

24. Overcoming Obstacles - Public Image (1) • 10 August: Fatal accident on Malaysian trawler kills six workers, five injured. Ammonia in refrigeration system is blamed in the press • 18 August: Further investigation suggests that ammonia was not to blame, but the workers were overcome by hydrogen sulphide • 25 August: It later transpires that the refrigeration system used R22, not ammonia • Questions: how far did the original news spread? How far did the later correction spread?

25. Overcoming Obstacles - Public Image (1) • 10 August: Fatal accident on Malaysian trawler kills six workers, five injured. Ammonia in refrigeration system is blamed in the press • 18 August: Further investigation suggests that ammonia was not to blame, but the workers were overcome by hydrogen sulphide • 25 August: It later transpires that the refrigeration system used R22, not ammonia • 1 October: ACR News – “An ammonia leak on a refrigeration system at a fish plant in Malaysia claimed six lives last month. The victims all died from ammonia inhalation”

26. Overcoming Obstacles - Public Image (2)

27. Overcoming Obstacles - Public Image (2)

28. 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

29. Design Considerations: Recommendations • Purchaser: • Specify EN378 as minimum design • Mandate detectors and alarms in unoccupied areas • Prohibit automatic plant room ventilation • Designer/Installer: • Ensure compliance with EN378 parts 2 and 3 • Design for minimum charge • Design for lifetime operation and efficiency • Operator: • Ensure that the plant is designed for maintenance • Conduct a HAZOP before the design is finished

30. Legislative Framework: Recommendations • Toxicity: • Raise the IDLH to 1000ppm • Mandate detectors and alarms in unoccupied areas • Prohibit automatic plant room ventilation • Flammability: • Stick with 3 classes (non-f, mildly-f and highly-f ) • Use other metrics if appropriate but apply them simply and consistently • Make the metric easy to measure and easy to validate • Public Image: • Don’t believe everything you read in the papers

31. Conclusions • Ammonia is safe if it is used correctly • It is easy to use, and reliable in operation • It offers exceptionally good efficiency • The two key drivers for increased adoption are: • Reduced charge systems • Enlightened regulation • Incentive will come from: • Training and familiarity • Technical Development • Economies of Scale