[Equest-users] Modeling an Existing Building - Calibrating to Utility Bills

[Michael Campbell]

I’ve made some changes to the model, so the updated model is attached.
Also, below are the consumption tables for electric, steam, and chilled
water.  The electric usage will not be accurate because I have not
accounted for plug loads yet, I’ve just used some arbitrary values.



*Start Date*

*End Date*


*Actual Electric Use (kWh)*

1/1/2013

1/31/2013

798,339

2/1/2013

2/28/2013

732,154

3/1/2013

3/31/2013

788,630

4/1/2013

4/30/2013

779,291

5/1/2013

5/31/2013

797,537

6/1/2013

6/30/2013

807,812

7/1/2013

7/31/2013

804,808

8/1/2013

8/31/2013

827,355

9/1/2013

9/30/2013

801,354

10/1/2013

10/31/2013

806,670

11/1/2013

11/30/2013

729,731

12/1/2013

12/31/2013

725,604



*Start Date*

*End Date*


*Actual Steam (klb)*


*Modeled Steam (klb)*

1/1/2013

1/31/2013

7,526

9,371

2/1/2013

2/28/2013

7,861

7,995

3/1/2013

3/31/2013

6,897

7,725

4/1/2013

4/30/2013

3,757

6,167

5/1/2013

5/31/2013

1,534

4,787

6/1/2013

6/30/2013

127

4,042

7/1/2013

7/31/2013

1,800

3,926

8/1/2013

8/31/2013

258

3,863

9/1/2013

9/30/2013

197

4,126

10/1/2013

10/31/2013

1,364

5,277

11/1/2013

11/30/2013

5,622

6,224

12/1/2013

12/31/2013

7,503

8,630



*Start Date*

*End Date*

*Actual Chilled Water (KTH)*

*Modeled Chilled Water (KTH)*

1/1/2013

1/31/2013

55.8

55.9

2/1/2013

2/28/2013

62.4

52.3

3/1/2013

3/31/2013

63.3

76.7

4/1/2013

4/30/2013

140.5

130.3

5/1/2013

5/31/2013

395.5

366.4

6/1/2013

6/30/2013

721.3

521.1

7/1/2013

7/31/2013

1,277.7

729.3

8/1/2013

8/31/2013

850.5

715.7

9/1/2013

9/30/2013

448.6

389.3

10/1/2013

10/31/2013

266.4

217.7

11/1/2013

11/30/2013

65.4

136.3

12/1/2013

12/31/2013

52.5

61.6



*Mike Campbell, E.I.T., LEED AP O+M*
*Sustainability Specialist*
*Sustainable Solutions Corporation*
Office: 610-569-1047

Mobile: 609-923-1743 <http://610-569-1047/>
www.SustainableSolutionsCorporation.com
<http://www.sustainablesolutionscorporation.com/>
*Sustainable Solutions Corporation is WBENC and BCorp Certified.*

*This email message and any attachments are for the sole use of the
intended recipient(s) and may contain confidential and privileged
information. Any unauthorized review, use, disclosure or distribution is
prohibited. If you are not the intended recipient, please contact the
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*From:* David Eldridge [mailto:DEldridge at grummanbutkus.com]
*Sent:* Wednesday, July 09, 2014 12:07 PM
*To:* Michael Campbell
*Cc:* equest-users at lists.onebuilding.org
*Subject:* Re: [Equest-users] Modeling an Existing Building - Calibrating
toUtility Bills



Mike, the below comments assume that you have electricity and steam matched
up fairly well. Otherwise you should present all of the discrepancies
together as these may provide clues to each other.



1) What are your calibration metrics now, and what are the targets?



2) When you look at the actual building there should be large lab AHUs that
will have cool enough air from OA to meet most cooling loads in the winter.



Are there any FCU or other single-zone cooling sources that might be
causing the cooling use in the model?



If not, can you run an hourly report showing the AHU cooling demand to
verify that these are the source?



3) Verify the range of the client's CHW meters. You may be calibrating to
data that has reduced accuracy at low flows.



DSE Mobile


On Jul 9, 2014, at 10:20 AM, "Kathryn Kerns" <kathryn.kerns at bceengineers.com>
wrote:

Michael, I suggest you take the written sequence of operation with a grain
of salt. Many years of experience has proved that just because a sequence
is written down, doesn’t mean the actual controls follow it. Chilled water
operation trend logs such as, supply and return loop temperatures, pump
status/speed, etc. would be very helpful diagnosing your problem. It is
possible that there is an OSA temperature cut off where the chilled water
system stops running completely or stops running to a non-critical area
that does not show up in the written sequence.  Another problem could be
that the 100% OSA heat exchanger doesn’t work the same in the winter as it
does in the summer. Sometimes, if you are use VAV cooling control, raising
the upper temperature limit from 65 F to 70 F on the WARMEST control will
lower winter cooling consumption. Then there is the variable infiltration
rate due to changing OSA temperature problem. In the end, you may just have
to fake something to get the cooling consumption to match. There are just
too many unknown variables. One of the reasons I avoid the LEED measurement
verification credit.


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

*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
<equest-users-bounces at lists.onebuilding.org>] *On Behalf Of *Michael
Campbell
*Sent:* Wednesday, July 09, 2014 7:41 AM
*To:* equest-users at lists.onebuilding.org
*Subject:* [Equest-users] Modeling an Existing Building - Calibrating
toUtility Bills



Hi,



I’m having some trouble calibrating my model to match the utility bills.
The issue I am trying to resolve right now is with the cooling energy.
Below is a table showing the metered chilled water usage for 2013.  As you
can see, the usage is minimal in the winter months and much higher in the
summer months.  This is a 100% OA laboratory building with fairly high
interior loads due to lab equipment.  It is a VAV system with district
chilled water cooling and district steam preheat, and hot water reheat
coils in the VAV boxes.    The problem I am having is that my modeled
chilled water usage is much higher in the winter than expected.  I have
tried just about everything I can think of without great results.  I have
attached the sequence of operations for the HVAC as well as the modeling
files.  If someone can take a look, that would be very helpful.



Thanks,





*Start Date*

*End Date*

*Chilled Water (KTH)*

1/1/2013

1/31/2013

55.8

2/1/2013

2/28/2013

62.4

3/1/2013

3/31/2013

63.3

4/1/2013

4/30/2013

140.5

5/1/2013

5/31/2013

395.5

6/1/2013

6/30/2013

721.3

7/1/2013

7/31/2013

1,277.7

8/1/2013

8/31/2013

850.5

9/1/2013

9/30/2013

448.6

10/1/2013

10/31/2013

266.4

11/1/2013

11/30/2013

65.4

12/1/2013

12/31/2013

52.5







*Mike Campbell, E.I.T., LEED AP O+M*
*Sustainability Specialist*
*Sustainable Solutions Corporation*
Office: 610-569-1047

Mobile: 609-923-1743 <http://610-569-1047/>
www.SustainableSolutionsCorporation.com
<http://www.sustainablesolutionscorporation.com/>
*Sustainable Solutions Corporation is WBENC and BCorp Certified.*

*This email message and any attachments are for the sole use of the
intended recipient(s) and may contain confidential and privileged
information. Any unauthorized review, use, disclosure or distribution is
prohibited. If you are not the intended recipient, please contact the
sender by reply email and destroy all copies of the original message and
any attachments.*



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