CLOSE CIRCUIT PRESSURE
CLOSE CIRCUIT PRESSURE
(OP)
Hello.
we have a close circuit chilled water system suppling the water to a heat exchanger located at 30 meters height, the pump is located at ground, the suction pressure is 4 barg and the dischrge is 8 barg.
when the pump is stopped what will be the pressure in the return line at 30 m height and at ground? will it be the same pressure?
what are the rules to calculate the pressures in close pumping circuits/
regards,
roker
we have a close circuit chilled water system suppling the water to a heat exchanger located at 30 meters height, the pump is located at ground, the suction pressure is 4 barg and the dischrge is 8 barg.
when the pump is stopped what will be the pressure in the return line at 30 m height and at ground? will it be the same pressure?
what are the rules to calculate the pressures in close pumping circuits/
regards,
roker





RE: CLOSE CIRCUIT PRESSURE
If you have high flowrates and suddenly stop a pump you can run into water hammer problems. Then a dynamic analysis is required to give you the transient pressure profile.
Cheers,
Joerd
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: CLOSE CIRCUIT PRESSURE
RE: CLOSE CIRCUIT PRESSURE
Do you have a chilled water surge and expansion drum near the suction of the pump? This would be my experience and joerd's as well I note.
The pressure at which this drum is operated at shutdown will be needed to determine the pressures at points of the system based on the elevation relative to that drum. From the info you have given, the pressure at the top of the loop (30m) could be 1 bar (i.e. holding 4bar on drum minus 30m of elevation) or vacuum (if water is allowed to slump into the drum at shutdown).
best wishes,
sshep