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

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Presentation on theme: "1 Using Ammonia Effectively Overcoming Obstacles and Maximising Benefits Dr Andy Pearson Star Refrigeration."— Presentation transcript:

1 1 Using Ammonia Effectively Overcoming Obstacles and Maximising Benefits Dr Andy Pearson Star Refrigeration

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

3 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 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 5 Reasons for wanting to use ammonia

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7 7 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 Reasons for wanting to use ammonia

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

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

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

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

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

13 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 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 15 ? Overcoming Obstacles - Toxicity 8 hour TLV 300ppm IDLH 700ppm IDLH? 1000ppm IDLH? 15 min TLV * Henderson and Haggard (1943) cited in AIHA Hygienic Guide Series (1971)

16 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 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 MJ/kg 20MJ/kg Class 2 LFL > 3.5 v/v HOC < 19MJ/kg LFL (ppm v/v) HOC (MJ/kg)

18 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 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 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

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22 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

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24 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 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 26 Overcoming Obstacles - Public Image (2)

27 27 Overcoming Obstacles - Public Image (2)

28 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 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 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: –Dont believe everything you read in the papers

31 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


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