[Equest-users] Baseline chiller unusual part load COP

[Rushi Quest]

Thanks David for taking out time to reply, will go through your suggestions
and follow up for any further queries.

On Thursday, March 25, 2021, David Eldridge <DEldridge at grummanbutkus.com>
wrote:

> Here’s another paper on the topic, the paper is old the methods should
> hold up if you make your own spreadsheet.
>
> Tools and Techniques to Calibrate Electric Chiller Component Models
> (taylor-engineering.com)
> <http://www.taylor-engineering.com/wp-content/uploads/2020/04/ASHRAE_Symposium_AC-02-9-1_Electric_Chiller_Model.pdf>
>
>
>
> David
>
>
>
> *David S. Eldridge, Jr.**, P**.**E**.**, BEMP, BEAP, HBDP, GGA*
>
> Associate
>
>
>
> Direct: (847) 316-9224 | Mobile: (773) 490-5038
>
>
>
> *Grumman/Butkus Associates* | 820 Davis Street, Suite 300 | Evanston, IL
> 60201
> <https://www.google.com/maps/search/820+Davis+Street,+Suite+300+%7C+Evanston,+IL+60201?entry=gmail&source=g>
>
> Energy Efficiency Consultants and Sustainable Design Engineers
>
>
>
> *grummanbutkus.com <http://grummanbutkus.com/>* | *Blog
> <http://grummanbutkus.com/blog>* | *Facebook
> <https://www.facebook.com/pages/GrummanButkus-Associates/1385285015032526>*
> | *Twitter <https://twitter.com/grummanbutkus>*
>
>
>
> *From:* Equest-users <equest-users-bounces at lists.onebuilding.org> *On
> Behalf Of *Rushi Quest via Equest-users
> *Sent:* Wednesday, March 24, 2021 12:36 PM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] Baseline chiller unusual part load COP
>
>
>
> Hi everyone,
>
>
>
> I am working on a office building project (e-quest 3.65-7175) in which
> baseline case is modelled following ASHRAE-90.1-2010 standard.
>
>
>
> Two centrifugal type chillers of 690TR each are assigned to the chilled
> water loop with full load COP value entered as 6.16 in chiller input tabs.
>
>
>
> As I was analysing the hourly reports for chiller, it was observed that
> chiller COP values (based on corrected EIR values in hourly report) are
> quite high ranging from 11 to around 25 at part load values in the range of
> 50% to 0.1%.
>
>
>
> This seems very unusual considering that as per chiller manufacturer part
> load datapoints the part load COP values starts decreasing below 35-30%
> part load; whereas using e-quest default chiller curves, the chiller COP
> value seems to go on increasing even at lower part load values.
>
>
>
> Has anyone observed this before, or am I going wrong somewhere?
>
>
>
> Also due to above issue, when part load data points provided by chiller
> manufacturer are entered in proposed model and default e-quest performance
> curves are used in baseline model, expected energy savings under space
> cooling consumption are not achieved during comparison.
>
>
>
> I have attached screen-shots showing e-quest default curve coefficients
> (EIR-FT, EIR,-fPLR & Cap-FT curves) for centrifugal chiller and a sample
> manufacturer's part load details for reference.
>
>
>
> Do I need to change the default curve coefficients from e-quest to get
> more accurate results? If so, please kindly let me know the changes to be
> made or the process for finding correct part load curve coefficients for
> chiller.
>
>
>
> Thanks in advance.
>
>
>
>
>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20210325/ab1d430d/attachment.htm>