<div dir="ltr">Thanks for the response, the total building load is 304 tons, and we will be dealing with chilled water as purchased, taking credit of the chiller plant is hard because you will need to satisfy the LEED "points floor" which is 6 points, this is equivalent to 22% of cost savings. So given that the chilled water is purchased, only the secondary pumps following the heat exchanger will be dealt with as downstream equipments and regardless of the load (i.e. even if the load is below 300 tons) these pumps must be variable for the base line, right?. the AHUs of the baseline are of the variable speed type, and by the way the climate of the project doesn't allow for the use of economizers, so no economizers are installed, also the building fabric for the proposed building will only save 1% energy 0.8% cost compared to the baseline fabric, the last factor of effect is lighting, say you can save 5 or 6% by daylight harvesting and more efficient fixtures, given all these data, achieving 10% cost savings will be extremely hard if not impossible I believe. please correct me if there is any factor I didn't consider.<br>
<br><div class="gmail_quote">On Wed, Sep 12, 2012 at 9:37 PM, Hall, Brendan <span dir="ltr"><<a href="mailto:BHall@karpinskieng.com" target="_blank">BHall@karpinskieng.com</a>></span> wrote:<br><blockquote style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class="gmail_quote">
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<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt">If you are a system 8 (Electric Heat), then the only pumps would be for chilled water. If your total cooling capacity is greater than 300 tons then the baseline
must have variable speed drives. Even if you are less than 300 tons it is a primary/secondary loop with pumps riding their curves so it’s less efficient but not straight constant volume. Also, with heat recovery it is important to look at how many hours you
would expect that it would run in your climate. For example, you would not want to run a ERU when a economizer would be available. There are obliviously other ways to get to 10% but it can be hard with district systems because by not being able to take credit
for having a chiller you are losing out on opportunity to gain efficiency. Good luck.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt">Brendan Hall<u></u><u></u></span></p>
<p class="MsoNormal"><span style="color:rgb(31,73,125);font-family:"Calibri","sans-serif";font-size:11pt"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="font-family:"Tahoma","sans-serif";font-size:10pt">From:</span></b><span style="font-family:"Tahoma","sans-serif";font-size:10pt"> <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a> [mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>]
<b>On Behalf Of </b>Yazan Abukhait<br>
<b>Sent:</b> Wednesday, September 12, 2012 2:26 PM<br>
<b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> [Equest-users] Would like to hear from you guys<u></u><u></u></span></p>
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<p class="MsoNormal">Dear all,<u></u><u></u></p>
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<p class="MsoNormal">I'm involved in a LEED project where my company have hired a LEED consultant, among the buildings is an office building consisting of 6 stories, being fed from a central utility plant located within the project, the base line is the same
that of the proposed building ( system 8) except that the VAV boxes are fan powered in the baseline. The mechanical engineer modeling the project is insisting that he can show a minimum of 10% energy savings by using variable speed pumps and AHUs and heat
recovery, I believe the heat recovery part, but using variable speed pumps and fans should also being modeled for the baseline as well, isn't it the case? ASHRAE 90.1-2007 will not allow you to use constant speed pumps for pumps and fans even when you use
the LEED supplemental document for district cooling plants treatment, would like to hear from you guys, and thanks in advance.<u></u><u></u></p>
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<p class="MsoNormal">Regards<u></u><u></u></p>
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