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<p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#20124d">Hi Tom,</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><font color="#20124d"><br><span style="font-size:12pt;font-family:"times new roman","serif""></span></font></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><font face="times new roman, serif" color="#20124d"><span style="font-size:12pt">You can model the aircooled chiller system as a </span><span style="font-size:16px">separate</span><span style="font-size:12pt"> system serving the treated outside air to various zones or system.</span></font></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#20124d">This can be done by making a system supplying to a dummy zone then the system serving the OA to various systems.</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#20124d">The supposed to be linked system comes in the outside air tab in air-side system.</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#20124d">To maintain the set-point you need to have design set-point below 60 degree.</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#20124d">In the model you need to have a design cooling set-point less than 60 degree for all the systems and then take help of SS-D report to have a look how the zone temperature is meeting the set-point.</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#20124d">For having the general system you can take packaged single zone and take hot water loop at the zone level (or system level).</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><br></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><b><font color="#660000">Thanks,</font></b></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""><font color="#990000">Sharad.Kumar</font></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-family:"times new roman",serif;font-size:12pt"><br></span></p><p style="margin-bottom:0.0001pt;line-height:normal" class="MsoNormal"><span style="font-family:"times new roman",serif;font-size:12pt">------------------------------ Forwarded message
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From: Tom Mickley via Equest-users
<<a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuildin<wbr>g.org</a>><br>
To: "<a href="mailto:equest-users@onebuilding.org" target="_blank">equest-users@onebuilding.<wbr>org</a>"
<<a href="mailto:equest-users@onebuilding.org" target="_blank">equest-users@onebuilding.org</a>><br>
Cc: <br>
Date: Thu, 22 Dec 2016 14:22:57 +0000<br>
Subject: [Equest-users] Packaged RTU w/ Precool Chiller</span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">Good morning,</span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">I’m molding an existing outpatient
facility and I’ve ran into an issue. </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">One of the HVAC units is a packaged
DX unit supplying a few surgical rooms. The HVAC was designed around a
class A or less operating room way back at the time of the original
install. They’ve since changed to class C operating rooms which have more
strict airflow requirements. The building owners decided to modify the existing
system rather than replace with new. </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">That being said, the unit is still a
DX cooled unit with in-duct steam humidification and HW reheat at the zone
level. There is electric backup heat in the unit if the boilers
fail. </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">Here’s the issue….</span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">The surgeons requested the rooms
maintain 60 degrees all year round. The existing unit couldn’t maintain
temperature. Therefore, there has been an air cooled packaged chiller
added with a chilled water coil attached to the outdoor air intake to cool and
dehumidify the outdoor air before entering the unit. </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">I cannot find a way to model DX and
chilled water at the same time. Does anyone have any suggestions? </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif""> </span></p>
<p style="line-height:normal" class="MsoNormal"><span style="font-size:12pt;font-family:"times new roman","serif"">Thanks in advance!</span></p>
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