[Equest-users] Total Site versus Total Source Energy BEPS

David S Eldridge DSE at grummanbutkus.com
Thu Oct 22 13:01:10 PDT 2009


I think if you modeled an on-site CHP system, the BEPS report should show roughly matching numbers for fuel consumed by a generator.

There may be a difference for source-to-site natural gas based on transportation from the gas well, but it shouldn't include the 25% waste heat from the diagram - that occurs on-site.

A value from the EPA is 4.7% for natural gas - so if eQuest used the same factor, I'd expect a CHP installation (assuming 100% of electricity usage was generated on-site) to show 4.7% difference between site and source in the BEPS report.

The link below will help explain:

http://www.energystar.gov/ia/business/evaluate_performance/site_source.pdf

The 25% losses of unrecoverable waste heat from the second diagram would be included in the on-site usage, and would show up in both lines of the BEPS.

David
____________________________________________________________________________________________________________________

David Eldridge, PE
LEED(r) AP, HBDP

Grumman/Butkus Associates | 820 Davis Street, STE 300 | Evanston, IL 60201 | Ph: (847) 328-3555, ext 224 | Fax: (847) 328-4550

Energy Consultants and Design Engineers
____________________________________________________________________________________________________________________





From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Vikram Sami
Sent: Thursday, October 22, 2009 2:27 PM
To: Jackson, Alan; James Geers
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Total Site versus Total Source Energy BEPS

In essence Alan is correct. However - for electric energy the largest losses are not the T&D losses (7.2% according to Wikipedia; 3% according to the chart below from the DOE) , but the conversion losses at the plant.  So the site-source utilization is around 33%

[cid:image001.jpg at 01CA5324.8383A010]

For an on-site CH&P generator, you would still have some losses - around 25% conversion loss, so the site-source utilization is around 75%, so there should still be a discrepancy between the two.
[cid:image002.jpg at 01CA5324.8383A010]

Vikram Sami, LEED AP
Direct Phone 404-253-1466 | Direct Fax 404-253-1366
LORD, AECK & SARGENT ARCHITECTURE

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Jackson, Alan
Sent: Thursday, October 22, 2009 1:15 PM
To: James Geers
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Total Site versus Total Source Energy BEPS

The Site is your building model. Source takes in to account losses and inefficiencies in delivery of energy from the source "plant", and hence reflects energy used at that source. If all energy was on site, they should be equal.

Alan Jackson, LEED AP
KlingStubbins

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of James Geers
Sent: Thursday, October 22, 2009 11:56 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Total Site versus Total Source Energy BEPS


I have noticed these two lines on my BEPS report.  Which number accurately reflects the energy consumption of my building?  What is the difference between the two?  If all of my energy was generated on site would the numbers be equal?







TOTAL SITE ENERGY      2517.74 MBTU     29.0 KBTU/SQFT-YR GROSS-AREA     29.0 KBTU/SQFT-YR NET-AREA

TOTAL SOURCE ENERGY    4867.80 MBTU     56.0 KBTU/SQFT-YR GROSS-AREA     56.0 KBTU/SQFT-YR NET-AREA





Thank you,




JAMES F. GEERS  |  ARCHITECT & LEED AP
513.721.0600 (x107) - DIRECT

SFA ARCHITECTS, INC.

CINCINNATI
300 WEST FOURTH STREET  |  CINCINNATI, OHIO 45202  |  513.721.0600 - OFFICE  |  513.721.0611 - FAX

DAYTON
120 WEST SECOND STREET  |  SUITE 1800  |  DAYTON, OHIO 45402  |  937.281.0600 - OFFICE  |  937.281.0611 - FAX

WWW.SFA-ARCHITECTS.COM<outbind://5-000000002A3AAC56F15D2E4D863C658A7EC1FD11C4022E00/www.sfa-architects.com>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20091022/a1bb19d5/attachment-0002.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 43883 bytes
Desc: image001.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20091022/a1bb19d5/attachment-0004.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 41918 bytes
Desc: image002.jpg
URL: <http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/attachments/20091022/a1bb19d5/attachment-0005.jpg>


More information about the Equest-users mailing list