NH3 thermosiphon oil cooler

[Josip]

Hi, cygbob

300KW, tube counts:717, circulation ratio:3:1, oil inlet/outlet temperature:80/40 Deg C, ammonia: 38/39 Deg C.

Here you have dT=1-2 C

251KW, oil:87.7/49, ammonia:33.3/35.4,

And here you have dT= 14-16 C

Are you sure in this values

Speaking about your scheme is the venting line from siphon receiver to condenser really connected in that way

Best regards, Josip

[cygbob]

Hi, cygbob



Here you have dT=1-2 C



And here you have dT= 14-16 C

Are you sure in this values

Speaking about your scheme is the venting line from siphon receiver to condenser really connected in that way

Best regards, Josip

Hi Josip,
Thnak you! Your question is very important, I don't why, but the values are measured a few days ago, I think except some measured errer they should be correct.

Another problem is that the fulid out of the condenser has a 9℃ sub-cooling! There must be something wrong with the system!

Best regards
cygbob

[US Iceman]

What is the diameter of the vent line pipe? And, what are the dimensions of the pilot receiver?

[cygbob]

What is the diameter of the vent line pipe? And, what are the dimensions of the pilot receiver?

the diameter of the vent line pipe is DN100,the pilot receiver dimension is about 1 m3

[US Iceman]

Based on a very quick review, the pipe sizes you have listed appear to be OK. The pilot receiver volume also appears sufficient.

In your last drawing you stated the liquid drain temperature from the condenser is 26.6 C (79.9 F), but after the liquid flows through the receiver the liquid ammonia temperature suddenly increases to 34.4 C (93.9 F).

What is the condensing pressure?

Can you provide a drawing of the internals of the receiver also please?

[cygbob]

Based on a very quick review, the pipe sizes you have listed appear to be OK. The pilot receiver volume also appears sufficient.

In your last drawing you stated the liquid drain temperature from the condenser is 26.6 C (79.9 F), but after the liquid flows through the receiver the liquid ammonia temperature suddenly increases to 34.4 C (93.9 F).

What is the condensing pressure?

Can you provide a drawing of the internals of the receiver also please?

ok! the condensing pressure is 12.7barg. the delivery gauge is about 35.5 ℃. the receiver is empty!
but ,I don't understand why the dT is so large!

best regarsds
cygbob

[NH3LVR]

You have a lot of subcooling! This may be affecting the continuous flow needed to keep the Thermosyphon vessel filled.
I recently ran into this problem. We had multiple condensers and plenty of capacity, but high head pressure and high subcooling. The piping for the equalizing line was questionable.
We valved off the inlet to one of the condensers and saw no major improvement. We started the purger (which was not piped well) and the head came down and everything worked fine.

[Andy]

Hi Cybob

I will go for the old favorites

1. liquid supply trapped going to the oil cooler

2.Incorrectly sized wet return riser from the oil cooler to the condenser

3. Oil trapped in the refrigerant shell.


If you check this and rule them out it will help you reach a valid conclusion

Kind Regards Andy