<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial, helvetica, sans-serif;font-size:10pt"><DIV>Hi Paul,</DIV>
<DIV>Hmmm. Those situations do sound complex and tricky. I've only had to deal "plain vanilla" central plants at this point. </DIV>
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<DIV>My thought/comment would be that it seems valid to use a simple cost for the chw or hw ($/therm etc.) in the DES step 2 models in lieu of modeling a central plant <U><EM>IF</EM></U> that cost is truly reflective of the central plant's efficiency.</DIV>
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<DIV>In the cases you describe below, it sounds like there may be a disconnect between cost and efficiency. Sounds like you would need to model a central plant in Step 2 that is reflective of the central plants efficiency. You could ignore any unusual methods (burnt trash etc) in the model. Then you could calc the dollar savings by hand afterward and deduct that via the exceptional calc or renewable energy savings on the EA cr 1 template. This seems like it would meet the requirement to reflect the actual efficiency of your central plant but still give you credit for the dollar savings associated with burnt trash or other energy saving or renewable measures.</DIV>
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<DIV>Before you go through a lot of work though, it may be worth your time doing a CIR or calling LEED to determine an acceptable approach.</DIV>
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<DIV>----- Original Message ----<BR>From: Paul Riemer <Paul.Riemer@dunhameng.com><BR>To: Julia Beabout <juliabeabout@yahoo.com>; "bldg-sim@lists.onebuilding.org" <bldg-sim@lists.onebuilding.org><BR>Sent: Friday, September 12, 2008 10:51:45 AM<BR>Subject: RE: [Bldg-sim] District Thermal System<BR><BR>
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<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>Julia,</FONT></SPAN></DIV>
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<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>I have been a bit up in arms about how this document will apply to s</FONT></SPAN><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>ome of the DESs serving our client community who are perhaps a bit unique in doing things like:</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>- billing buildings only on peak demand (not consumption)</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>- generating chilled water from waste heat outside of CHP situation</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>- generating heat by burning some rather cheap things including garbage</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2> (if they get paid to take it and burn it, probably best to just count it as free and not press the luck on a negative fuel cost) </FONT></SPAN></DIV>
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<DIV dir=ltr align=left><FONT face=Arial><FONT color=#0000ff><FONT size=2><SPAN class=632081614-12092008><FONT size=+0><SPAN class=632081614-12092008>I have been assuming that the Step 2 template would have to include the proposed DES energy consumption documented in primary sources like electricity and natural gas and the corresponding costs extended from those specific consumption numbers. </SPAN></FONT></SPAN>T<SPAN class=632081614-12092008>hat could get pretty complicated for some of the above scenarios.</SPAN></FONT></FONT></FONT></DIV>
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<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>Your tact looks considerably simpler and could remain abstracted above my questions about detailed fuel sources and detailed utility rates.</FONT></SPAN></FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2></FONT></SPAN></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2>Thank you all for your comments so far and please do share if you have a Step 2 approach reviewed.</FONT></SPAN></FONT></SPAN></DIV>
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<DIV dir=ltr align=left><SPAN class=632081614-12092008><FONT face=Arial color=#0000ff size=2><SPAN class=632081614-12092008>Paul Riemer</SPAN></FONT></SPAN></DIV>
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<FONT face=Tahoma size=2><B>From:</B> Julia Beabout [mailto:juliabeabout@yahoo.com] <BR><B>Sent:</B> Wednesday, September 10, 2008 10:57 AM<BR><B>To:</B> Paul Riemer; Karen Walkerman; Eric Youngson<BR><B>Cc:</B> bldg-sim@lists.onebuilding.org; bldg-rate@lists.onebuilding.org<BR><B>Subject:</B> Re: [Bldg-sim] District Thermal System<BR></FONT><BR></DIV>
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<DIV>Let me reiterate, that I have not submitted my model yet to LEED. So, I don't have any feedback from them regarding the validity of my take on things. </DIV>
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<DIV>In aswer to your question: Yes and no. :)</DIV>
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<DIV>The way I see things:</DIV>
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<DIV>For Step 1, the DES document talks about using a "market" rate for the DES utilities. So, my take on that is that if there is a general prevailing rate for these utilities in your area, that should be used in Step 1. Where as the intent for Step 2 seems to be to use info (i.e. a rate or other method as discussed below) that reflects your plant's actual efficiency. </DIV>
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<DIV>In theory, for Step 1, the rate shouldn't matter since it's effect is neutralized by using it in both the proposed and baseline models. However, I'm thinking there may be a situation where if you have a really stellar (i.e. low CHW, steam, HW rate) or poor (i.e. high CHW, steam, or HW rate) performing proposed central plant and you use that rate in Step 1 in both the proposed and baseline models, it may impact your results in Step 1. Although, again, in theory, it shouldn't matter. But, as I do more models, it seems that the relationship between $ saved and the % saved is not linear - i.e. as you demonstrate more and more savings, it seems easier to get to the next LEED increment with smaller amounts of deltas - and vice versa (which to some degree makes sense since dividing by smaller numbers). But, I'm thinking this effect could impact your savings in Step 1
and thus your ability to even get to Step 2. But, maybe I'm off base here. I'm speculating at this point in that regard.</DIV>
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<DIV>That being said, it does seem that the rate you used in Step 1 could be the same rate used in Step 2 for your proposed building and thus, the performance shown for the proposed building models on the LEED templates could be the same in both Steps. </DIV>
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<DIV>Another idea I had was that the DES rate could be used to back calculate the overall COP/efficiency of your plant. And then use those figures in your proposed model for Step 2. It may be easier to adjust those rates for distribution losses etc. All this assumes that your DES rate is based on metered data and actual production costs. It seems LEED may want some demonstration of this. </DIV>
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<DIV>----- Original Message ----<BR>From: Paul Riemer <Paul.Riemer@dunhameng.com><BR>To: Julia Beabout <juliabeabout@yahoo.com>; Karen Walkerman <kwalkerman@gmail.com>; Eric Youngson <ericy@pae-engineers.com><BR>Cc: "bldg-sim@lists.onebuilding.org" <bldg-sim@lists.onebuilding.org>; "bldg-rate@lists.onebuilding.org" <bldg-rate@lists.onebuilding.org><BR>Sent: Wednesday, September 10, 2008 11:07:16 AM<BR>Subject: RE: [Bldg-sim] District Thermal System<BR><BR>
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<DIV dir=ltr align=left><SPAN class=013135614-10092008><FONT face=Arial color=#0000ff size=2>Julia,</FONT></SPAN></DIV>
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<DIV dir=ltr align=left><SPAN class=013135614-10092008><FONT face=Arial color=#0000ff size=2>Thank you for your comments. Please allow me to ask a bit more.</FONT></SPAN></DIV>
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<DIV dir=ltr align=left><SPAN class=013135614-10092008><FONT face=Arial color=#0000ff size=2>Are you stating that Table 1.8.2(b) at the bottom of your Step 2 EAc1 template will have an energy type line item of "hot water", "steam", or "chilled water"? If so, will the numeric energy use value (e.g. 1,234 MBtu) be exactly the same as in Step 1's EAc1 template? Meaning the only differences between the proposed columns of the two submittal templates will be the dollar costs of the DES energy stream and total costs?</FONT></SPAN></DIV>
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<DIV dir=ltr align=left><SPAN class=013135614-10092008></SPAN><SPAN class=013135614-10092008><FONT face=Arial color=#0000ff size=2>Paul Riemer</FONT></SPAN></DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B> bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org] <B>On Behalf Of </B>Julia Beabout<BR><B>Sent:</B> Wednesday, September 10, 2008 9:32 AM<BR><B>To:</B> Karen Walkerman; Eric Youngson<BR><B>Cc:</B> bldg-sim@lists.onebuilding.org; bldg-rate@lists.onebuilding.org<BR><B>Subject:</B> Re: [Bldg-sim] District Thermal System<BR></FONT><BR></DIV>
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<DIV>I just finished my first DES project (not submitted yet, though) and have a couple more in the works. </DIV>
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<DIV>I agree with the interpretations below especially with respect to Step 2 and the utilization of the DES purchased rates as an acceptable means of reflecting the prposed/actual central plant's efficiency in the proposed energy model. Although, the DES purchased rates should reflect/be adjusted for the items Karen mentions. Additionally, I'd recommend confirming that the DES rate includes all the central plant's bits and pieces. The maintenance costs should also be extracted from the DES rate if possible. (The DES document seems to clarify that the maintenance costs do not need to be included. So, if those can be extracted that will be more of an apples to apples comparison with the baseline model and work in your proposed model's favor). </DIV>
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<DIV>In my estimation, the above method provides the most expedient, realistic and accurate method of determining the central plant's efficiency. The trick is that that info is not always available - especially in a campus situation. So, in that case you may need to use one of the other methods of modeling the central plant discussed in the DES document: other metering data, modeling of the central plant equipment, etc. However, sometimes even this data can be hard to come by and/or is not within the project's ability or budget to determine or model. So, in that type of situation, the default central plant efficiency values provided in the DES document could be used. </DIV>
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<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">----- Original Message ----<BR>From: Karen Walkerman <kwalkerman@gmail.com><BR>To: Eric Youngson <ericy@pae-engineers.com><BR>Cc: bldg-sim@lists.onebuilding.org; bldg-rate@lists.onebuilding.org<BR>Sent: Tuesday, September 9, 2008 3:08:28 PM<BR>Subject: Re: [Bldg-sim] District Thermal System<BR><BR>
<DIV dir=ltr>I am also in the middle of a DES project at the moment. The way that I interpreted Step 1 and 2 is as follows:<BR><BR>Step 1:<BR><BR>Baseline: all downstream (on-site) equipment, envelope components, etc, as in Appendix G. heating and cooling is purchased from a DES system.<BR>Proposed: all downstream (on-site) equipment, envelope components, etc, as designed. Heating and cooling is purchased from a DES system.<BR><BR>Step 2:<BR><BR>Baseline: all equipment is modeled as on-site. Boilers and Chillers are to be modeled as designed in Appendix G. Utility rates are to be local utility rates<BR>Proposed: building is to be modeled as built. Heating and cooling is purchased from a DES system, energy costs must take into account DES production and transmission losses.<BR><BR>In my opinion, the vocabulary in Table 1 is confusing, but the guidelines on pages 5 and 6 seem pretty clear. Am I on the same page as
everyone else here?<BR><BR>Thanks,<BR><BR>--<BR>Karen<BR><BR></DIV></DIV></DIV></DIV></BLOCKQUOTE></DIV></DIV></DIV></BLOCKQUOTE></DIV></DIV></div></body></html>