<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:10pt">Neil:<br><br>I have modeled VRF systems as PTHP systems for high rise residential buildings where the required baseline system is a PTHP.<br><br>The compressor on the PTHP can be specified as variable speed. so it seems to work well. I just finished a 7 story building using a Daikin system. I built 4 custom curves per condensing unit and used the exceptional calculation method outlined in the BSUG slide presentation to calculate the recovered energy. The curves I created are the Cooling Capacity f(EWB,ODB), Cooling EIR f(EWB,ODB), Heating Capacity f(EDB, ODB) and Heating EIR f(EDB, ODB). <br><br>I ended up with a 28% cost savings for the proposed HVAC system compared to the baseline 90.1-2004 system which is in the range claimed by the manufacturer.<br><div> </div>Paul
Diglio, CEM, CBCP<br><br><div>87 Fairmont Avenue<br>New Haven, CT 06513<br>203-415-0082</div><br><br><div><span><a target="_blank" href="http://www.pdigliollc.com">www.pdigliollc.com</a></span><div><br></div><div style="font-family:times new roman, new york, times, serif;font-size:10pt"><br><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Neil Bulger <nbulger@integralgroup.com><br><b><span style="font-weight: bold;">To:</span></b> Loi Ng <Lng@DIVENG.COM>; "equest-users@onebuilding.org" <equest-users@onebuilding.org><br><b><span style="font-weight: bold;">Sent:</span></b> Thu, January 12, 2012 4:21:19 PM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [Equest-users] Help - Modeling VRV-VRF System with eQuest<br></font><br>
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--></style><div class="WordSection1"><p class="MsoNormal"><span style="color:#1F497D;">Hi Loi,</span></p><p class="MsoNormal"><span style="color:#1F497D;"> </span></p><p class="MsoNormal"><span style="color:#1F497D;">I have run across this as well with trying to model VRV in eQuest. PVVT is a difficult system to work with because it requires specifying 1 zone as the thermostat that drives the whole system. Therefore, 1 zone will drive what supply air temperature the central AHU delivers to each zone. This can make hours out of range on cooling difficult but, if heating is the issue you may have more flexibility with zone-level heating options (reheat or baseboards). However, that can start to look strange when in reality, these features do not exist. But, the hours out of range typically stem from this single-zone-thermostat issue with PVVT.</span></p><p class="MsoNormal"><span style="color:#1F497D;"> </span></p><p class="MsoNormal"><span
style="color:#1F497D;">Another approach I have not perfected yet that I thought of was to try using the eQuest Water Heat Pump system. The Water Heat Pump ties to a WLHP water-loop (it appears yellow in the Water-Side tab). If you were to place a dry-cooling tower on this loop, effectively, the dry cooling tower would be (in my mind) the same as an air-source condenser, like we would see in reality with a VRV system (typically).</span></p><p class="MsoNormal"><span style="color:#1F497D;"> </span></p><p class="MsoNormal"><span style="color:#1F497D;">This may be good or bad on the airside in eQuest (I am hoping good) in that it provides another set of options and heat flow control at each system. Again, I have not dug into how this would go together best and I would imagine some post processing would be needed to understand the results.</span></p><p class="MsoNormal"><span style="color:#1F497D;"> </span></p><p class="MsoNormal"><span
style="color:#1F497D;">Would love to hear any other creative ideas out there for VRV work-arounds.</span></p><p class="MsoNormal"><span style="color:#1F497D;"> </span></p><div><p class="MsoNormal"><b><span style="font-size:8.5pt;font-family:"sans-serif";color:gray;">Neil Bulger</span></b><span style="color:gray;"><br></span><span style="font-size:8.5pt;font-family:"sans-serif";color:gray;">Project Engineer</span></p><p class="MsoNormal"><b><span style="font-size:8.5pt;font-family:"sans-serif";color:#99CC00;">________________________________</span></b><span style="color:#1F497D;"></span></p><p class="MsoNormal"><span style="font-family:"sans-serif";color:#999999;">I N T E G R A L</span></p><p class="MsoNormal"><b><span style="font-size:8.5pt;font-family:"sans-serif";color:#999999;">
</span></b><b><span style="font-size:8.5pt;font-family:"sans-serif";color:gray;"> </span></b><b><span style="font-size:8.0pt;font-family:"sans-serif";color:gray;">GROUP</span></b><span style="font-size:8.0pt;font-family:"serif";color:gray;"></span></p><p class="MsoNormal"><span style="font-size:8.5pt;font-family:"sans-serif";color:#999999;"> </span></p><p class="MsoNormal" style="margin-bottom:6.0pt;"><span style="font-size:8.5pt;font-family:"sans-serif";color:gray;">427 13th Street, Oakland CA 94612</span><span style="color:gray;"><br></span><span style="font-size:8.5pt;font-family:"sans-serif";color:gray;">510 663 2070 x 235<br></span><span style="color:#1F497D;"><a rel="nofollow" ymailto="mailto:nbulger@integralgroup.com" target="_blank" href="mailto:nbulger@integralgroup.com"><span
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style="font-size:10.0pt;font-family:"sans-serif";">From:</span></b><span style="font-size:10.0pt;font-family:"sans-serif";"> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Loi Ng<br><b>Sent:</b> Thursday, January 12, 2012 9:38 AM<br><b>To:</b> equest-users@onebuilding.org<br><b>Subject:</b> [Equest-users] Help - Modeling VRV-VRF System with eQuest</span></p></div></div><p class="MsoNormal"> </p><p class="MsoNormal">Hi,</p><p class="MsoNormal"> </p><p class="MsoNormal">I am modeling VRV system based on a “Energy Trust of Oregon, Inc.” guidance document (attached) posted by Mathew Larson of Colorado dated 12/12/2011. The document recommends using a PVVT system to simulate a VRV system. I used an air cooled PVVT system to model a VRV system. However, the unmet hours on the heating is very high. The cooling part is okay. Does
anyone has experience on bringing down the unmet hours?</p><p class="MsoNormal"> </p><p class="MsoNormal">Thanks! </p><p class="MsoNormal"> </p><p class="MsoNormal"><b><span style="font-size:14.0pt;font-family:"Bradley Hand ITC";">Loi Ng</span></b></p><p class="MsoNormal"><span style="font-size:9.0pt;font-family:"sans-serif";">Mechanical Engineer</span><span style="font-size:12.0pt;font-family:"sans-serif";">, </span><span style="font-size:9.0pt;font-family:"sans-serif";">LEED<sup>®</sup> AP</span><span style="font-size:12.0pt;font-family:"sans-serif";"></span></p><p class="MsoNormal"><span style="font-size:9.0pt;font-family:"sans-serif";color:#0070C0;">Diversified Engineering, Inc.</span></p><p class="MsoNormal"><span style="font-size:9.0pt;font-family:"sans-serif";color:#0070C0;">914 Silver Spring Avenue, Suite 208</span></p><p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"sans-serif";color:#0070C0;">Silver Spring, MD 20190</span></p><p class="MsoNormal"><span style="font-size:9.0pt;font-family:"sans-serif";color:#0070C0;">Tel: 301-565-2000 x 234</span></p><p class="MsoNormal"><span style="font-size:9.0pt;font-family:"sans-serif";color:#0070C0;">Fax 301-495-1563 </span></p><p class="MsoNormal"> </p></div></div></div></div>
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