I am a Mech Eng with no HVAC experience, but have been asked to help with a 25yr old Glycol chiller. System has been "badgered" over the years, and documumentation is almost non existant. I have been trying to reverse engineer the thing, but have a few questions. First - what I do know:
Continental NUPAC air cooled chiller (w remote condenser)
9 ton (nominal) capacity
fluid: 40% EG
flow rate: 50gpm
Ent temp: 15 deg F
Lvg temp: 10 deg F
Ambient Temp: 65 deg F
Low Ambient to -20 deg F
hot gas bypass
head pressure control + 2 speed condenser fan
My first thought was to get into the pressure enthalpy diagram. Is a good assumption for the design high pressure side to be:
65 + 30 = 95 deg F - corresponds to 129 psia
What is a good assumption for the low pressure side design temp/pressure? Would it be 10 deg F (leaving glycol) minus some standard # for the evaporator?
I have dug up alot of information on all of the individual components in the system. Just not the "nominal" operating conditions. Any suggestions or help with a "plan of attack" would be much appreciated....
Just FYI - the system is not meeting spec, and I have been asked if I can figure out why not.