<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Guo:<br><br>I don't have an instant solution, but let me try to understand your system.<br><br>This SOUNDS like essentially a "face and bypass" system, where you have a Cold Deck and a Neutral Deck. The Neutral Deck is where Outside Air is introduced.<br><br>But both deck do not have any dampers varying the flow from one deck to another.<br><br>Unless I misunderstood your description.<br><br>Is this a correct interpretation ??<br><br>--- On <b>Tue, 9/15/09, v i <i><hijkyyyy@yahoo.com></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: v i <hijkyyyy@yahoo.com><br>Subject: [Equest-users] Model DOAS & (AHU + 4-pipe Fan COil) in parallel using eQUEST?<br>To: Equest-users@lists.onebuilding.org<br>Date: Tuesday, September 15, 2009, 7:33 AM<br><br><div id="yiv1072522277"><table
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">I m trying to model a building served mainly by the following systems</font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">1. <b style="">Four </b>ventilating air handlers condition all the entering outside air for the building to 72 degree F. </font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">2. <b style="">Four</b> air handling units with return fans (they all have <b style="">cool-decks only, No Outside Air intakes</b>) that circulate and condition the return air of the whole building to 55 degree F.</font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3"><font face="Times New Roman"><b style="">Note: The 4 cool-deck-only air handling units don’t draw air straight off the ventilating air handling systems, instead they work in parallel. The conditioned air off each of </b>the<b style=""> </b>cool-deck-only air handlers<b style=""> only gets mixed with the conditioned air off </b>the ventilating air handler<b style=""> right before being discharged off each floor diffusers.</b></font></font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">3. The rest of the building air conditioning is done through the parameter 4-pipe fan coils system.</font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">The entire building’s cooling and heating demand relies on district chilled water and steam. </font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">Could you shed some light on how to model this system correctly? </font>
</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">My initial thought was to model it as an <b style="">Induction Unit (an air handler + the 4 pipe fan coils system) </b>with its outside air drawn from the dummy zone served by the Ventilating air handler. But in reality the cool-deck-only air handler doesn’t draw air straight off the ventilation air handlers. </font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">your suggestions and inputs are highly appreciated.</font>
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</p><p class="MsoNormal" style="margin: 0in 0in 0pt;"><font size="3" face="Times New Roman">Guo</font>
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