chilled water variable secondary pumping & Controls
chilled water variable secondary pumping & Controls
(OP)
We are going to install 1200 TR chiller with Variable Secondary Pump(1140 cmh) & Fixed Primary Pump(452 cmh).
The variable secondary Pump will be suitable to Handle 3000TR.
The present Load is only 800 TR
Which is the best economic way to control the secondary pumps.
with 3000TR flow , when it"s feeding to 800TR with VFD, the pressure head will be sufficient to serve the end use point.
whether we can control the VFD of secondary loop upto 30% of the rated Flow.
Please guide me in details.
Navas
The variable secondary Pump will be suitable to Handle 3000TR.
The present Load is only 800 TR
Which is the best economic way to control the secondary pumps.
with 3000TR flow , when it"s feeding to 800TR with VFD, the pressure head will be sufficient to serve the end use point.
whether we can control the VFD of secondary loop upto 30% of the rated Flow.
Please guide me in details.
Navas





RE: chilled water variable secondary pumping & Controls
RE: chilled water variable secondary pumping & Controls
The specified condition is to be followed. so i need a better guidance for the above.
RE: chilled water variable secondary pumping & Controls
RE: chilled water variable secondary pumping & Controls
If the chiller capacity is 1200TR then the primary pump capacity should atleast be 727 cmh. The maximum secondary pump capacity should be equal to that of primary pump capacity. Multiple primary pumps and one secondary pump is exactly opposite to what an optimum design should be. Review your design once and cover the loop holes.
As far as your question is concerned, 30% is not a very bad flowrate for the secondary pumps to run but not very good either. You pump speed control should be done not based on flowrate but on the DP across the secondary supply and return headers. This will ensure that necessary head is developed by the pump at all load conditions.
RE: chilled water variable secondary pumping & Controls
the temperature difference is 8C & The secondary pump is of 62 m Head. i am worried if VFD works at 30% speed , then sufficient head will be developed or not.
Please guide me
RE: chilled water variable secondary pumping & Controls
RE: chilled water variable secondary pumping & Controls