<html><body bgcolor="#FFFFFF"><div>This discussion has perhaps underlined the differences in terminology between the US (where a significant part of development takes place) and the rest of the world. </div><div><br></div><div>For example, in the UK 90%+ of systems using an AHU are "DOAS" but I'd never heard of the term before dealing with E+. </div><div><br></div><div>Another thing we have come accross is the applcation of Fancoil systems appears to vary significantly between the US and EU. In Europe most fan coil systems are augmented by "DOAS". They can also be quite advanced pieces of kit with electically commutated (EC) fan motors for efficiency. </div><div><br></div><div>This is merely my observation from E+ where the Fourpipe fancoil object is quite dumb (i.e. Single speed fan that doesn't modulate on/off with the load).</div><div><br></div><div>I say quite dumb... It's obviously more clever than me!</div><div><br>Sent from my iPhone</div><div><br>On 27 Mar 2010, at 09:44, "James V Dirkes II, PE" <<a href="mailto:jvd2pe@tds.net">jvd2pe@tds.net</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>
<div class="Section1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">Dear Sambhav,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">There is good information available from ASHRAE which you should
read about DOAS.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D">A brief understanding is that certain HVAC systems, such as
chilled beams, VRF and water-source heat pumps, are used to remove <u>zone</u>
sensible cooling or heating loads. They are very effective at this
function but do not provide <u>outdoor air ventilation</u> for the zones.
As a result, a separate HVAC system is provided for the express purpose of
providing ventilation air. This is called a Dedicated Outdoor Air System
(DOAS).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" align="center" style="text-align:center"><b><span style="font-size:13.5pt;color:#1F497D">The Building Performance Team<br>
</span></b><b><span style="color:#1F497D">James V. Dirkes II, P.E., LEED AP<br>
</span></b><span style="color:#1F497D">1631 Acacia Drive NW<br>
Grand Rapids, MI 49504<br>
616 450 8653<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D"><o:p> </o:p></span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:10.0pt;
font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;
font-family:"Tahoma","sans-serif""> <a href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a>
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>sambhav
tiwari<br>
<b>Sent:</b> Saturday, March 27, 2010 12:37 AM<br>
<b>To:</b> <a href="mailto:bldg-sim@lists.onebuilding.org"><a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a></a><br>
<b>Subject:</b> [Bldg-sim] DOAS system<o:p></o:p></span></p>
</div>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:.5in">Hi All,<br>
I
would like to know what is DOAS system for what purpose it is used .I have only
heard about it but not used in any of the projects. It wil be so nice if anyone
can tell for what applications it is used.<br>
<br>
Thanks<br>
Sambhav Tiwari.<o:p></o:p></p>
</div>
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