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[Tycho]

Tycho,
Any reason you know of as to not use PHE economizer?
less liquid in system, compact, maybe cheaper.
Just a thought
Put it in suggestion box at work, see what engineering department say.

I know what the engineering department would say to a PHE, and from the designs I have seen, I am prone to agree with them.

You would need some kind of thermostatic expansion valve on the cold side (compressor economizer suction) to control the superheat through the economizer PHE, and unless you have a very stable liquid feed from the HP receiver to the LP receiver (through the economizer), you will get a very erratic economizer pressure, as I see it, and very little subcooling of the liquid from the hp receiver as it passes through the PHE to quickly.


While the tank we are using has might hold 100 kg of nh3, it has 50 meters of pipe coiled inside that are submerged in liquid -20 - -15 liquid, so even when the compressor is working with full slide, but low load on the system, we still get subcooled liquid and a higher load on the economizer port.


if that makes sense