Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

variable speed primary chilled water system 1

Status
Not open for further replies.

dk2499

Mechanical
Joined
Oct 4, 2005
Messages
1
Location
US
What is the best control strategy for not going beyond a chillers maximum rate of flow change, while still controlling the VFD's based off of zone differential pressure. IE if the controller sees a sudden drop in zone dp, it will increase the drive speed to compensate. In doing so, you could exceed the recommended 10% per minute change in flow rate.
 
The recommended maximum % change in flowrate generally corresponds to a temperature control with a precision of +/-0.50C and it depends upon how tight a control you require. However, you can have your VSD run with a set ramp up rate to match the recommended maximum change.

This is for a variable primary flow application. If you have only secondary variable flows, this doesn't matter at all.

 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top