I?ve performing an energy model to compare VFD Chiller
pumping and Constant Volume Chiller pumping for a multi-story office building
using eQUEST v 3.65. Although I expect to save pump energy utilizing VFD
pumping I?m not seeing a savings and I believe this is due to my ?Pump
Properties Inputs?.

For both the VFD and constant volume pump scenarios I?ve
input the scheduled pump flow (1,300 gpm) and head (200 ft) and the other pump
inputs are default values. The energy difference between the two pumping
scenarios is negligible, however, if I set the pump gpm to a default, which
inputs a 1.00 Flow Ratio, the energy savings is significant in the VFD pumping
model.

Am I over defining the pumps by inputting the scheduled pump
gpm? Should the pump gpm always be set to default?

Thanks,

Michael