[Equest-users] VFD Pumping

[Joe Fleming]

Hi Michael,

 

To add to what Paul mentioned about 2-way valves;

 

What are your building loads looking like in the eQuest output reports?
There are 2 potential scenarios that may lead to limited savings from a
properly modeled VFD installation;

1.       If the pump is under sized for the loads input 

2.       If the loads are constant and mostly internal

 

Kind Regards

 

 

Joe Fleming |  PE, LEED AP BD+C, BEMP

Commissioning Agent & Energy Consultant | The Spinnaker Group

 <mailto:joe at thespinnakergroupinc.com> joe at thespinnakergroupinc.com

Cell  561-602-3132  |  Office  754-800-3100 

 

From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On
Behalf Of Mike Schaefer
Sent: Thursday, June 18, 2015 2:49 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] VFD Pumping

 

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
  

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