Minimum discharge pressure for ammonia systems

[Mark Sanchez]

Andy,

Great point. I would like to see the chart as well. I'm sure someone has one for the States.

We have installed a few systems with the wetbulb sensors.
It would really only seem to matter if you're operating a large system with a low disch. press. setting, and it was set below the actual saturation corresponding to WB. Mainly in the middle of summer.
Chicago has a design of 95/78 (not if you refer to the latest ASHRAE, but the NH3 guys still use it) so a corresponding saturation = approx 132# Disch.

If you did not have the WB feature, the system would try and run more condenser fans/ pumps w/ no avail. as the saturated Disch press. setting was not attainable. Or you can stop a VFD on a condenser fan from driving higher if in fact you have already achieved the WB/ Saturation.

I'll have to look into the Sabroe system.
This sounds very interesting.
I'll forward the link for this site to Greg @ M&M to see if he knows anything about it.

It's great too see so many technicians & engineers involved with this site!!

Cheers
Mark.

I'll introduce myself if I see you at IIAR