I have some questions about modeling VFD pumps in a closed loop is it the only way to model VFD pumps by putting the values for Speed vs efficiency curve as below figure? and if so let say if i enter 8 points this means that we define 8 characteristic curves for the one VFD pump?
and for the BEP flow and BEP efficiency if i have 8 characteristic curves this means i should add BEP for each one or just for pump at full speed ?
and the same for the curve Multi points flow Vs Head what points exactly to enter ?? i have max allowable flow, Min allowable flow and duty , should i enter all of them at full speed or for the 8 curves?
what data should be enter for the VFD pumps to run the software without any issues ??
The way I would analyze this situation is to create an EPS run with a time pattern for speed (Pattern > Pump pattern) such that the speed changes fro 1, .95, .9, .85, .8 ... In the pump property grid, pick Pattern Based and select that pattern
Make an EPS run that covers the range of speeds and plot, the pump curves (right click on pump and pick Pump Curve). Pick all the times you want and plot them.
This will show you the flow, head and efficiency at each speed.
It will also show you how the pump head curve and efficiency curve vary over the range of speeds.
Also note that there is a difference between the variable speed option for defining the efficiency, and modeling a pump whose speed changes (scaling the pump curve up and down). See: "Is variable speed drive?" vs "Is variable speed pump?"
Jesse DringoliTechnical Support Manager, Haestad ProductsBentley Communities Site AdministratorBentley Systems, Inc.
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