Anhydrous ammonia (NH3), or R-717, is an efficient refrigerant that has environmental advantages, including non-ozone depleting properties and low climate impact. While ammonia is effective and requires smaller components than other refrigerants, it is also toxic and corrosive, necessitating safety precautions during use. Systems containing ammonia must adhere to strict regulations based on their size, and personal protective equipment is essential for those working in environments with ammonia.

1. Anhydrous Ammonia (NH3)
as a Refrigerant
An Overview

2. Introduction:
 What is Ammonia?
 Why is it used as a refrigerant?
 What are some of it’s properties?
 How does it compare to other refrigerants?
 Is it safe?

3. Anhydrous Ammonia (NH3):
 Also known as R-717
 It is a single component refrigerant.
 One part nitrogen, three parts hydrogen.
 Anhydrous means void of water content.

4. Environmentally Friendly:
 Does not deplete the ozone.
 Does not contribute to climate change.
 Leaks are easily detectable.

5. Properties:
 Ammonia has less volume than comparable
refrigerants. On large systems it requires smaller
piping and smaller components.
EXAMPLE:
Tons of refrigeration per 100 equivalent feet of
pipe. R-134a: 11/8” copper = 28.4 tons liquid
2.3 tons suction
R-717: 1” iron pipe = 126 tons liquid
3.8 tons suction

6.  Ammonia and oil do not mix well, so
keeping oil in the compressor is less
difficult.
 Ammonia is miscible with water, so it is
easily diluted, and easily washed away.
 Ammonia is corrosive to copper alloys

7. How Does it Compare?
 R-12 Boils at –20 degrees at 0 lbs.
 R-134a Boils at –14 degrees at 0 lbs.
 R-717 Boils at –28 degrees at 0 lbs.
Ammonia is 3% more efficient than R-22 & 10%
more efficient than R-134a
EXAMPLE: At 32 psig suction
R-12 = 34 degrees
R-134a = 37 degrees
R-717 = 19 degrees

8. Safety:
 Ammonia is toxic and corrosive.
 When mixed with oxygen it will burn.
 Ammonia is lighter than air.
 Ammonia can be easily diluted with water.
 Small amounts of can be dispersed into a container of water.
 Personal Protective Equipment (PPE) should always be used
when working with Ammonia.
(i.e. neoprene gloves, eye goggles, full face shield, canister type respirator)

9.  Equipment rooms must be well ventilated.
 Egress should be well marked and unobstructed.
 Make others aware that you are working on the
equipment.
 Equipment rooms must have a detection & alarm
system.
 Systems under 10,000 lbs. on site fall under the state
and the EPA
 Systems over 10,000 lbs. fall under Home Land
Security. Every pound must be tracked and
accounted for.

10.  The average odor threshold is 5 ppm.
 100-200 ppm: Eyes irritated.
 500 ppm & below: No permanent eye damage.
 300 ppm: Immediate throat irritation.
 1700 ppm: Coughing
 2400 ppm: Threat to life after 30 minutes exposure.
 5000 ppm: Vapor – Full body chemical suit required.
 5000 ppm: Liquid – Second degree burns and blisters.

11. Check out some pictures of an ammonia
refrigeration system!

12. Computer control panel on a 500 ton Frick screw machine

13. Labeled ammonia piping in the machine room

14. Ammonia piping in the machine room

15. Thermal siphon tank in the machine room

16. Liquid ammonia receiver tank

17. 500 ton Frick screw machine

18. 500 ton Frick screw machine

19. Ammonia accumulator

20. Torn down liquid ammonia pump

21. Ammonia transfer vessel and pump

22. Value station for an evaporator

23. Valve station for an evaporator

24. Evaporative condensers for ammonia plant

25. Main plant and valve station control center

26. Three 500 ton Frick screw machines in plant

27. The End