Mr. Dirkes and Mr. Spangler,<br><br>Thank you so much for both of your inputs on this. I am clear with the concept of oversizing and also what Appendix G says.<br><br>Thanks again!<br><br><div class="gmail_quote">On Thu, Jun 24, 2010 at 7:16 AM, Seth P. Spangler <span dir="ltr"><<a href="mailto:sspangle@rmf.com">sspangle@rmf.com</a>></span> wrote:<br>
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<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(0, 112, 192);">Vinay,</span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(0, 112, 192);"> </span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(0, 112, 192);">You are to increase the cooling/heating coil capacities as
required by ASHRAE Appendix G. However, the over sizing is for coil capacity
only – the airflow rate should be sized at 100% of what your energy modeling
program calculates as being required to meet the space load.</span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(0, 112, 192);"> </span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(0, 112, 192);">Thanks</span></p>
<p class="MsoNormal"><span style="font-size: 10pt; color: rgb(0, 112, 192);"> </span></p>
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<p class="MsoNormal"><span style="font-size: 10pt; font-family: "Georgia","serif"; color: rgb(0, 112, 192);">Seth Spangler, LEED® AP </span></p>
<p class="MsoNormal"><span style="font-family: "Georgia","serif"; color: rgb(0, 112, 192);"> </span></p>
<p class="MsoNormal"><span style="font-size: 10pt; font-family: "Georgia","serif"; color: rgb(0, 112, 192);">RMF Engineering, Inc </span></p>
<p class="MsoNormal"><span style="font-size: 10pt; font-family: "Georgia","serif"; color: rgb(0, 112, 192);">Ph: (843) 971-9639 ext:1497</span><span style="color: rgb(0, 112, 192);"></span></p>
<p class="MsoNormal"><span style="font-size: 10pt; font-family: "Georgia","serif"; color: rgb(0, 112, 192);">Fax: (843) 971-9641 </span></p>
<p class="MsoNormal"><span style="font-size: 10pt; font-family: "Georgia","serif"; color: rgb(0, 112, 192);"><a href="mailto:sspangle@rmf.com" target="_blank">sspangle@rmf.com</a></span><span style="font-size: 11pt; color: rgb(0, 112, 192);"></span></p>
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<p class="MsoNormal"><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;">
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>James V
Dirkes II, PE<br>
<b>Sent:</b> Wednesday, June 23, 2010 7:16 PM<br>
<b>To:</b> 'Vinay Devanathan'; <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br>
<b>Subject:</b> Re: [Bldg-sim] sizing for baseline case acc to App. G</span></p>
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<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">Dear Vinay,</span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);">I’m not sure of the rationale for the ASHRAE 90.1
oversizing requirements, however here are my thoughts:</span></p>
<p><span style="font-size: 11pt; font-family: Symbol; color: rgb(31, 73, 125);"><span>·<span style="font: 7pt "Times New Roman";">
</span></span></span><span style="font-size: 11pt; color: rgb(31, 73, 125);">I think the principal engineering rationale for oversizing is to
allow a building to reach its setpoint temperature quickly after a period of
inactivity. As an example, if a building is inactive during a holiday and
the temperature is allowed to float several degrees lower (in winter), the
additional 25% heating capacity will enable faster return to the normal
setpoint temperature. Steam heating systems can need even more capacity
for proper warmup capacity.</span></p>
<p><span style="font-size: 11pt; font-family: Symbol; color: rgb(31, 73, 125);"><span>·<span style="font: 7pt "Times New Roman";">
</span></span></span><span style="font-size: 11pt; color: rgb(31, 73, 125);">Oversizing is also a common practice as a “safety
factor”. Most load calculation software even has a separate input
for adding this “safety factor”. </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="font-size: 11pt; color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal" style="text-align: center;" align="center"><b><span style="font-size: 13.5pt; color: rgb(31, 73, 125);">The Building Performance Team<br>
</span><span style="color: rgb(31, 73, 125);">James V. Dirkes II, P.E., LEED AP<br>
</span></b><span style="color: rgb(31, 73, 125);">1631 Acacia Drive NW<br>
Grand Rapids, MI 49504<br>
616 450 8653</span></p>
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<p class="MsoNormal" style="margin-left: 0.5in;"><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;"> <a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Vinay
Devanathan<br>
<b>Sent:</b> Wednesday, June 23, 2010 10:00 AM<br>
<b>To:</b> <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br>
<b>Subject:</b> [Bldg-sim] sizing for baseline case acc to App. G</span></p>
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<p class="MsoNormal" style="margin-left: 0.5in;">Hello All,<br>
<br>
Just to clarify a point - <br>
<br>
What does the oversizing of capacities by 15% for cooling and 25% for heating
exactly mean? Do we only size the cooling and heating capacity or also increase
the airflow rate corresponding to the oversizing?<br>
<br>
Thank you.</p>
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