subcooler ammonia

[davidlleida]

Hi everybody,
first, please forgive my bad english
My question is:
In a 2 stage cicle with ammonia overfeed, what option is better:
1) discharge from low stage compressor (-30, -10) to a subcooler where there is subcooling of liquid feeding -30ºC separator
2) or discharge from LS compressor directly to separator at -10ºC
I think is better a subcooler because that way the separator is not inflenced for the discharge from LS compressor,
are there differences in returning of oil from compressors ?
thank you for your help
davidlleida

[US Iceman]

1) discharge from low stage compressor (-30, -10) to a subcooler where there is subcooling of liquid feeding -30ºC separator

The liquid subcooling is better because the cold liquid improves the refrigeration effect of each pound (kilogram) of ammonia. The subcooling also allows you have 100% liquid (no flash gas) at the expansion devices.

[davidlleida]

Thank you so much!, I understand that it's the same example as comparing a tipical shell and coil intercooler where the liquid gets colder than a flash intercooler where there is no liquid cooling...?

[US Iceman]

I think you have it correct.