Electricity consumption mismatch between model and bill

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Hello,

I am currently struggling with a problem concerning the electricity consumption of the building I modeled in eQuest. eQuest predicts a way higher electricity consumption than it actually was billed for by the power provider. eQuest predicts a usage of about 330 MWh a year and the actual bills were at 73MWh for a year. Being sure that the power provider doesn't give away free electricity, I am currently trying to figure out where I made a mistake.

One possible problem could be, that I included all the mechanicals (like pumps, AHU, fan, unit heater, boiler,...) in the plug loads (misc. equipment), which I read later, I should not do. But I am also not able to find where I can correct it without going back to the wizard and losing all my changes made in detailed mode. Now it is only shown as equipment load which (if I understand correctly) includes my plug loads and also the electricity consumption calculated by eQuest of the HVAC system. So is the consumption of the HVAC system accounted for twice? Since I only want to redo my plug loads, how can I do that without interfering with the eQuest calculation of the HVAC electricity usage? Any help with that?

Also, these loads should not be a majority of the building and the overall consumption will still be too high (at least that's my guess). Anyone ever had the same problem?
Lights consumption is about correct.

Thank you for your help.

Inga Goebel

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Hi Inga,

As per my understanding the correction that i can suggest is the correction
in schedules.
The electrical consumption that you are inferring in the eQUEST as 330 MWh
and the actual bills are 73 MWh.
Now you are as a suggestion is required to fetch the actual working hour of
the type wise hourly use of the segments.
There can be minor or major mismatch in the hourly usage which sometime can
have slight or above mismatch.
Kindly get the hourly usage data from the electrical consultant and if seen
do the correction in the schedules.
This is the only correction that i am able to think right now.
Hope this might help.

*Thank sand Regards,*
Sharad.Kumar
Freelancer
India..

-----------------------------------------------------------------------------------------------------------------------------

1. Electricity consumption mismatch between model and bill
(Inga Goebel)

---------- Forwarded message ----------
From: Inga Goebel
To: "'equest-users at lists.onebuilding.org'" <
equest-users at lists.onebuilding.org>
Cc:
Bcc:
Date: Fri, 25 Oct 2019 19:52:53 +0000
Subject: [Equest-users] Electricity consumption mismatch between model and
bill

Hello,

I am currently struggling with a problem concerning the electricity
consumption of the building I modeled in eQuest. eQuest predicts a way
higher electricity consumption than it actually was billed for by the power
provider. eQuest predicts a usage of about 330 MWh a year and the actual
bills were at 73MWh for a year. Being sure that the power provider doesn?t
give away free electricity, I am currently trying to figure out where I
made a mistake.

One possible problem could be, that I included all the mechanicals (like
pumps, AHU, fan, unit heater, boiler,?) in the plug loads (misc.
equipment), which I read later, I should not do. But I am also not able to
find where I can correct it without going back to the wizard and losing all
my changes made in detailed mode. Now it is only shown as equipment load
which (if I understand correctly) includes my plug loads and also the
electricity consumption calculated by eQuest of the HVAC system. So is the
consumption of the HVAC system accounted for twice? Since I only want to
redo my plug loads, how can I do that without interfering with the eQuest
calculation of the HVAC electricity usage? Any help with that?

Also, these loads should not be a majority of the building and the overall
consumption will still be too high (at least that?s my guess). Anyone ever
had the same problem?

Lights consumption is about correct.

Thank you for your help.

Inga Goebel

_______________________________________________
Equest-users mailing list
Equest-users at lists.onebuilding.org
http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org

Sharad Kumar2's picture
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Hello Sharad:

equest-users at lists.onebuilding.org; equest-users at lists.onebuilding.org

Welcome to the world of whole-building energy simulation. Unfortunately, getting a simulation to match the utility bills for a specific building can be a challenge. There's a good review of the many methods that have been developed over the years in Coakley et al.

https://www.sciencedirect.com/science/article/abs/pii/S1364032114003232

In general, you need to have a process that "matches" those measurements that you can match, and then "calibrate" the rest to get the best match of the whole-building simulation. One of the earliest papers that provided a systematic method was Hsieh et al., which described the process for an office building in New Jersey.

https://www.sciencedirect.com/science/article/abs/pii/0378778894900051

More recently, newer methods have been proposed that begin to consider inputs that were previously assumed. For example, indoor temperatures when considering motion sensors on thermostats, for example Kim and Oldham's paper on modeling occupancy-based controls in hotels

http://scholar.google.com/scholar_url?url=https%3A%2F%2Foaktrust.library.tamu.edu%2Fhandle%2F1969.1%2F88028&hl=en&sa=T&ct=res&cd=2&d=2178238779268168983&ei=ZNq1XeGYIojYygSsz7KwDA&scisig=AAGBfm2IHuKrSyMK8rYGTWiIi3U9iZUNCQ&nossl=1&ws=1280x595&at=Review%20and%20Recommendations%20of%20Existing%20Methods%20and%20Tools%20for%20Building%20Energy%20Analysis%3A%20Subtask%202.4%20for%20the%20Southern%20Energy%20Efficiency%20Center&bn=1

Or, Shin et al's paper on modeling occupancy-based controls in a net zero building at Ft. Hood.

http://www.ibpsa.org/proceedings/BS2017/BS2017_346.pdf

And of course there are the classic papers, including Bronson et al.

https://www.osti.gov/biblio/6885248

Or even Bou Saada et al's work

https://asmedigitalcollection.asme.org/solarenergyengineering/article-abstract/120/3/193/435764

Hopefully, these will give you a sense of how to proceed.

Jeff

Graphical tools to help calibrate the DOE-2 simulation program (Journal Article) | OSTI.GOV
www.osti.gov
The U.S. Department of Energy's Office of Scientific and Technical Information

Jeff S. Haberl, Ph.D., P.E.inactive, FASHRAE,FIBPSA

Department of Architecture

Texas A&M University

College Station, TX 77845-3581

Office: 979-845-6507, Lab: 979-845-6065

Fax 979-862-2457

jhaberl at tamu.edu,www.esl.tamu.edu

Jeff Haberl2's picture
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Hello Sharad (again):

I also wanted to mention the important work that Janet Manke and Doug Hittle developed for the Gunnison Airport in Colorado in the 1990s where they spelled out how you "calibrate" the model by systematically varying the important inputs from 1/10 to 10x to get the best fit...

https://www.osti.gov/biblio/438671

Jeff

Calibrating building energy analysis models using short term test data (Book) | OSTI.GOV
www.osti.gov
The U.S. Department of Energy's Office of Scientific and Technical Information

Jeff

Manke, J., Hittle, D. and Hancock 1996. ?Calibrating building Energy Analysis Models Using Shortterm Test Data,? Proceedings of the 1996 International ASME conference.

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