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MrReds
11-03-2012, 08:41 PM
Hi there,
Hope you are fine.
I was analyzing the evaporators utilizing NH3 as refrigerant.
I have noticed that they have a tube diameter bigger than evaporators utilized for standard HFC refrigerants, ex 5/8 Vs .
As consequence, the internal volume is bigger.

According to my point of view, the reasons are
- ammonia coolers are utilized for larger thermal loads than standard DX coolers. Since they are used in a flooded mode they are used in systems where mass flow is higher than DX ones.
- Ammonia liquid density is lower than other refrigerants density. Therefore it is needed an higher tube section.

Please, what is your point of view ? Do you agree with my interpretation ?
Many thanks

Magoo
12-03-2012, 12:07 AM
Ammonia gives you more bang for the dollars compared to the other options, [ circulated volume for refrigeration effect ] the application can often dictate the use of piping and material options available for evaporators. The newer generation evaporators are using thin wall and small bore stainless steel tubing.