<HTML dir=ltr><HEAD><TITLE>Re: [Bldg-sim] Building rotation per Appendix G</TITLE>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>Hello,</FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>I asked a question a few weeks ago about whether or not you have to rotate the Baseline building in a LEED-NC EAc1 calculation (or Appendix G calculation for some other reason).<SPAN style="mso-spacerun: yes"> </SPAN>Thank you everyone for your replies (see below)…it appears that yes, you do need to perform the four (4) separate runs for each direction.</FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT size=3><FONT face="Times New Roman">However, I have a more general question about modeling renovations to existing buildings.<SPAN style="mso-spacerun: yes"> </SPAN>According to the LEED-NC reference guide, you are to model the Baseline building (if it is existing) with the same “thermal parameters” as the existing building.<SPAN style="mso-spacerun: yes"> </SPAN>Appendix G, Table G3.1 Section 5f) says that “For Existing building envelopes, the baseline building design shall reflect existing conditions prior to any revisions that are part of the scope of work…”.<SPAN style="mso-spacerun: yes"> </SPAN></FONT></FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>Futhermore, the reference guide goes on to say that “For projects served by existing HVAC systems, such as a central plant on a campus, Section 10(a) of Table G3.1 states that when there is an existing HVAC system, the model shall reflect the actual system type using actual component capacities and efficiencies.”</FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>But this section is actually under the “Proposed” column, and I can’t find anywhere where it specifically says that the Baseline system should be modeled as the existing building currently stands.</FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>So I have two questions:</FONT></P>
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<P class=MsoListParagraphCxSpFirst style="MARGIN: 0in 0in 0pt 0.5in; TEXT-INDENT: -0.25in; mso-list: l0 level1 lfo1"><FONT face="Times New Roman"><SPAN style="mso-list: Ignore"><FONT size=3>1)</FONT><SPAN style="FONT: 7pt 'Times New Roman'"> </SPAN></SPAN><FONT size=3><SPAN style="mso-spacerun: yes"> </SPAN>If you have an existing building, is the HVAC system supposed to be modeled as it currently exists in the Baseline model, as well as things like the thermal parameters, etc?<SPAN style="mso-spacerun: yes"> </SPAN>What about the lighting?<SPAN style="mso-spacerun: yes"> </SPAN>If you have an existing building that you KNOW has a lighting density of 2.0 Watts / sq ft pre-retrofit, is that how you should model the Baseline building?</FONT></FONT></P>
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<P class=MsoListParagraphCxSpMiddle style="MARGIN: 0in 0in 0pt 0.5in; TEXT-INDENT: -0.25in; mso-list: l0 level1 lfo1"><FONT face="Times New Roman"><SPAN style="mso-list: Ignore"><FONT size=3>2)</FONT><SPAN style="FONT: 7pt 'Times New Roman'"> </SPAN></SPAN><FONT size=3>If I have an existing building that happens to have one exposure with NO windows, and part of the renovation is to install windows on that side of the building, while STILL BEING BELOW 40% total window area. How do I model the baseline building?<SPAN style="mso-spacerun: yes"> </SPAN>With windows there or not?<SPAN style="mso-spacerun: yes"> </SPAN>If not, then that is a major penalty, and in reality, I may want to compare my Proposed building to a Baseline model that is 90.1-2004 compliant.<SPAN style="mso-spacerun: yes"> </SPAN>Can you even do that if it is an existing building?<SPAN style="mso-spacerun: yes"> </SPAN>Can you choose whether to model the Baseline building it as it exists, or model it per minimum ASHRAE standards? </FONT></FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT size=3><FONT face="Times New Roman">I haven’t yet received a copy of 90.1-2007.<SPAN style="mso-spacerun: yes"> </SPAN>Does Appendix G in that version clarify any of this?<SPAN style="mso-spacerun: yes"> </SPAN></FONT></FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>Thanks in advance!</FONT></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>James Hansen</FONT></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>GHT Limited</FONT></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT face="Times New Roman" size=3>703-243-1200</FONT></P></FONT></DIV></DIV>
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<FONT face=Tahoma size=2><B>From:</B> bldg-sim-bounces@lists.onebuilding.org on behalf of Dakota Kelley<BR><B>Sent:</B> Wed 10/22/2008 4:15 PM<BR><B>To:</B> Kevin Kyte<BR><B>Cc:</B> bldg-sim@lists.onebuilding.org<BR><B>Subject:</B> Re: [Bldg-sim] Building rotation per Appendix G<BR></FONT><BR></DIV>
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<P><FONT size=2>Kevin,<BR><BR>I have since reversed my stance; Eric O'Neill was kind enough to provide<BR>me with the following link:<BR><BR><A href="http://lists.onebuilding.org/htdig.cgi/bldg-sim-onebuilding.org/2007-Nov">http://lists.onebuilding.org/htdig.cgi/bldg-sim-onebuilding.org/2007-Nov</A><BR>ember/005709.html<BR><BR>I had not come across this thread before, and it sounds like existing<BR>buildings need to be rotated regardless of the situation.<BR><BR>Dakota<BR><BR>-----Original Message-----<BR>From: Kevin Kyte [<A href="mailto:kkyte@robsonwoese.com">mailto:kkyte@robsonwoese.com</A>]<BR>Sent: Wednesday, October 22, 2008 3:00 PM<BR>To: Dakota Kelley; JHANSEN@ghtltd.com<BR>Cc: bldg-sim@lists.onebuilding.org<BR>Subject: RE: [Bldg-sim] Building rotation per Appendix G<BR><BR>What if it is an existing building and there have been alterations to<BR>the<BR>floorplan?<BR><BR>-----Original Message-----<BR>From: bldg-sim-bounces@lists.onebuilding.org<BR>[<A href="mailto:bldg-sim-bounces@lists.onebuilding.org">mailto:bldg-sim-bounces@lists.onebuilding.org</A>] On Behalf Of Dakota<BR>Kelley<BR>Sent: Wednesday, October 22, 2008 3:16 PM<BR>To: JHANSEN@ghtltd.com<BR>Cc: bldg-sim@lists.onebuilding.org<BR>Subject: Re: [Bldg-sim] Building rotation per Appendix G<BR><BR>James,<BR><BR>It is my understanding that it is not necessary to do the rotation on an<BR>existing building. I am also working on an existing building, and I<BR>plan to submit without rotating. This topic has been debated on the<BR>forum in the past with opposing opinions, each side having reasonable<BR>arguments, but if my memory is correct the best/last argument was that<BR>existing buildings do not need to be rotated. I think this position<BR>makes more intuitive sense, too.<BR><BR>I don't believe a definitive resource exists for this question, which is<BR>why I plan to "learn the hard way" on my project. I have heard that<BR>2009 LEED revisions will address questions specific to existing<BR>buildings; hopefully this will be one of them. In the interim, I would<BR>ask that anyone with a differing opinion specify the resource guiding<BR>them.<BR><BR>Dakota Kelley<BR>Telios Engineers<BR><BR>-----Original Message-----<BR>From: bldg-sim-bounces@lists.onebuilding.org<BR>[<A href="mailto:bldg-sim-bounces@lists.onebuilding.org">mailto:bldg-sim-bounces@lists.onebuilding.org</A>] On Behalf Of<BR>bldg-sim-request@lists.onebuilding.org<BR>Sent: Wednesday, October 22, 2008 2:02 PM<BR>To: bldg-sim@lists.onebuilding.org<BR>Subject: Bldg-sim Digest, Vol 11, Issue 20<BR><BR>Send Bldg-sim mailing list submissions to<BR> bldg-sim@lists.onebuilding.org<BR><BR>To subscribe or unsubscribe via the World Wide Web, visit<BR> <BR><A href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org</A><BR>or, via email, send a message with subject or body 'help' to<BR> bldg-sim-request@lists.onebuilding.org<BR><BR>You can reach the person managing the list at<BR> bldg-sim-owner@lists.onebuilding.org<BR><BR>When replying, please edit your Subject line so it is more specific<BR>than "Re: Contents of Bldg-sim digest..."<BR><BR><BR>Today's Topics:<BR><BR> 1. Building rotation per Appendix G (James Hansen)<BR> 2. About weather data files (M F A Ramadan)<BR><BR><BR>----------------------------------------------------------------------<BR><BR>Message: 1<BR>Date: Tue, 21 Oct 2008 17:15:28 -0400<BR>From: "James Hansen" <JHANSEN@ghtltd.com><BR>Subject: [Bldg-sim] Building rotation per Appendix G<BR>To: <bldg-sim@lists.onebuilding.org><BR>Message-ID:<BR> <BR><25F2BDB6656B8F40A1289ED906D6B5CF038E117F@EXCHANGE1.cadd_group.ghtltd.co<BR>m><BR> <BR>Content-Type: text/plain; charset="us-ascii"<BR><BR>I'm working on a project where I am pursuing LEED EAc1 for an existing<BR>building. As I understand it from the LEED-NC reference guide, as well<BR>as from some snippets of 90.1, I actually model the baseline building as<BR>is currently exists. The reference guide says:<BR><BR>"For existing buildings that are being renovated, the building envelope<BR>design parameters for the Baseline Design should be modeled using the<BR>existing (pre-retrofit) building envelope thermal parameters rather than<BR>the ASHRAE 90.1 prescriptive building envelope requirements for the<BR>specified climate."<BR><BR>So I'm using actual window areas, actual insulation values, etc.<BR><BR>My question is: if I'm using this exception, do I also no longer have<BR>to do a simulation at the four different azimuth required by the LEED<BR>EAc1 template?<BR><BR>I find 90.1, as well as the user's manual, fairly lacking in describing<BR>how to apply Appendix G to existing buildings in general....<BR><BR>Thanks in advance!<BR><BR>GHT Limited<BR>James Hansen, PE, LEED AP<BR>Senior Associate<BR>1010 N. Glebe Rd, Suite 200<BR>Arlington, VA 22201-4749<BR>703-338-5754 (Cell)<BR>703-243-1200 (Office)<BR>703-276-1376 (Fax)<BR><A href="http://www.ghtltd.com">www.ghtltd.com</A> <<A href="http://www.ghtltd.com/">http://www.ghtltd.com/</A>><BR><BR></FONT></P></DIV></BODY><!--[object_id=#ghtltd.com#]--><P align=left><FONT size=2><FONT face=Tahoma><FONT color=#0000ff>
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