Chiller Primary & Secondary Pump Flow Rate

[Timothi]

Experts,
I request your valuable comments on the case below,

Two numbers of 80 TR (W,S) chillers are installed for a commercial building of 100 TR cooling demand. Chillers are designed considering 20% diversity factor. There is a constant flow primary pump set with water flow rate 200 GPM (2.5gpm/TR). Should we maintain VFD secondary pump set water for at 250 gpm or 200 gpm is sufficient? Kindly advise




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[BronYrAur]

The whole point of having a VFD on your secondary system is that the flow will vary. So you will not have a constant 200 GPM or 250 GPM. You most likely have 2-way valves on the air handler coils, so the secondary flow can get much lower than 200 GPM during light load conditions.

 

[dbill74]

A diagram/schematic of the system would be helpful.