[Equest-users] VFD in chillers

[James Hess]

Your option is to request 20 data points from the chiller manufacturer, for various temperatures and loads, then let eQuest curve fit that data, so that you have custom performance curves which represent the VFD operation.

You could use more data than 20 points and do the curve fits yourself in Excel, and then transfer the coefficients back to eQuest.  If you research curve fits on this forum, there are some excellent posts covering this.

I think 20 points to represent chiller performance is adequate.

My experience is that if a firm has a good relationship with chiller vendors (i.e. works on several projects with chillers), the chiller vendors should work with you to provide the requested data.  The chiller vendors will want their chillers shown in the best possible light with regards to energy savings, LEED, etc.  The best way to do that is via custom performance curves which more accurately reflect chiller performance.

Hope this helps.

Regards,

JAH

James A. Hess, PE, CEM, BEMP
Energy Engineer
TME, Inc.
Little Rock, AR
Mobile: (501) 351-4667

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Sambhav Tiwari
Sent: Wednesday, May 08, 2013 7:32 AM
To: equest-users
Subject: [Equest-users] VFD in chillers

Hi Equesters,
                     I have one building where the screw chillers have VFD control but the provision of doing this is not available in software.

Kindly let me know how can i claim the saving.

Thanks
Sambhav Tiwari
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