[Equest-users] Customized Chiller Performance Curve

[Brian Fountain]

Nitin,

I do not believe you have sufficient data points in your part load curve to define the chiller curves.  While you have selection points for chiller capacity and chiller EIR with varying condenser water temperature and with varying loads, in all cases the chilled water temperature is constant at 45F.  This means the coefficients on chilled water temperature are unconstrained.  I suspect that is leading to the odd results.  To properly define the chiller part load curve you additionally need chiller selections with the condenser water held constant as the chilled water and loads are both varied..

Chilled water temperature is not shown in your hourly report but I would expect that as chilled water moves away from your 45F design point the capacity and input power will move further from realistic expectations.

I hope this helps.

Brian



Footprint

Brian Fountain


From: Equest-users <equest-users-bounces at lists.onebuilding.org> On Behalf Of Nitin Harjai via Equest-users
Sent: Friday, March 12, 2021 5:41 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Customized Chiller Performance Curve

CAUTION: EXTERNAL SENDER
Hi Everyone,

I am facing a problem in my project regarding the output of chiller equipment when I am considering the customized chiller curve using the chiller details form chiller datasheet.

We know how the eQuest do the calculation for the space cooling energy consumption:- "There is a formula to calculate the corrected EIR by software i.e., Correction to EIR for PLR x Correction to EIR for temperature x AHRI EIR at 100% and this calculated corrected EIR is multiplied to operating capacity of chiller to work out the space cooling energy consumption."

It has been noticed using the customized hourly report for chillers that the correction to EIR for temperature & AHRI EIR at 100% is negative throughout the year. I have attached the hourly results report for your reference.

Further if I do the reverse calculation for AHRI EIR at 100% using the values available from customized hourly report (Correction to EIR for PLR x Correction to EIR for temperature & corrected EIR ) it never comes the same as what I have entered EIR at chiller lever.

Please find the attached screenshot of customized chiller curve entered, screenshot of EIR at 100% entered at the chiller level and chiller part load details from manufacturer.

Has anyone faced the same issue? Waiting for the valuable reply from you all eQuest champs.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20210312/c790bc6b/attachment.htm>