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    <font size="+1"><tt>I haven't done a VRF system so my remarks apply
        to trying to get multiple zones under control using a single
        thermostat.  The biggest problem is you probably do not have
        enough airflow to begin with to carry the heat required.  The
        eQuest default is 0.5 chm/SF.  Once you get into heating
        dominated climates this is not nearly enough air to accomplish
        your heating with the air handler.  eQuest will size your
        airflow to handle the cooling demand which it has done in your
        case but leaves you with some pretty extreme under heated
        hours.  Start bringing up your cfm/SF up in 5% increments
        starting at 1.0 cfm/SF.  Monitor your heating capacity of your
        air handler(s) on the SV-A page.  The SS-J heating peaks will
        also start to increase.  Once you aren't getting any change in
        your heating capacity of the system air handler you have gone
        far enough and may need to backtrack a bit.  You can adjust your
        throttling range a bit say to 4 deg instead of 2.  You can
        adjust your control zone, or the location of your T-stat to see
        if you can find a better location.  Your main tool is the
        cfm/SF.  In my area, much colder than Oregon I get into the 1.2
        to 1.25 cfm/SF range.  On one I just did the under heated hours
        per zone went from the 900-1000 hour range down to 40 to 180
        hours for some of the trouble zones with a majority in the 0 to
        10 hour range.  Then I added in the baseboards and all the under
        heat hours vanished.  You don't want to use the baseboards for
        control too fast as you want to have your AHU carry the majority
        of the load because your AHU will typically use gas to heat and
        your baseboards will use electricity.  I think this will work
        with either work around for VRF.  You have a heat coil and a
        cooling coil each at a specific temperature.  The only other
        variable you have to heat or remove heat from your zone is your
        airflow.  So eQuest has provided your maximum airflow required
        for cooling at around 0.5 cfm/SF, it will adjust the flows to
        different zones, your increased airflow for heating will give
        you the approximate maximum flows required for heating.  So you
        have basically sized your terminal unit flow.  With your maximum
        heating and cooling effects all on the AHU you will get a better
        picture of what your work around system will have to handle. 
        Excessive heating with the baseboards could give you a false
        picture if you are not careful, you just want them for trimming
        to get your errors to disappear and hopefully most of your
        warnings.  They do provide the heating differentials from the
        control zone.  The SV-A will also give you a good picture of
        what is happening in each zone.  Other reports will help you
        track down trouble zones, what is happening and hopefully why.<br>
        Bruce Easterbrook P.Eng.<br>
        Abode Engineering<br>
      </tt></font><br>
    On 12/01/2012 04:21 PM, Neil Bulger wrote:
    <blockquote
cite="mid:E9AD575374574E439EA4C93EC054103A80F65493E9@vesuvius2.rumseyengineers.com"
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        <p class="MsoNormal"><span style="color:#1F497D">Hi Loi,<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></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.<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></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).<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></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.<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D">Would love to
            hear any other creative ideas out there for VRV
            work-arounds.<o:p></o:p></span></p>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
        <div>
          <p class="MsoNormal"><b><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:gray">Neil
                Bulger</span></b><span style="color:gray"><br>
            </span><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:gray">Project
              Engineer<o:p></o:p></span></p>
          <p class="MsoNormal"><b><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:#99CC00">________________________________</span></b><span
              style="color:#1F497D"><o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-family:"Arial","sans-serif";color:#999999">I
              N T E G R A L<o:p></o:p></span></p>
          <p class="MsoNormal"><b><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:#999999">               
                         </span></b><b><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:gray"> </span></b><b><span
style="font-size:8.0pt;font-family:"Arial","sans-serif";color:gray">GROUP</span></b><span
              style="font-size:8.0pt;font-family:"Times New
              Roman","serif";color:gray"><o:p></o:p></span></p>
          <p class="MsoNormal"><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:#999999"><o:p> </o:p></span></p>
          <p class="MsoNormal" style="margin-bottom:6.0pt"><span
style="font-size:8.5pt;font-family:"Arial","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:"Arial","sans-serif";color:gray">510
              663 2070 x 235<br>
            </span><span style="color:#1F497D"><a moz-do-not-send="true"
                href="mailto:nbulger@integralgroup.com"><span
style="font-size:8.5pt;font-family:"Arial","sans-serif"">nbulger@integralgroup.com</span></a></span><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:gray"><br>
            </span><span style="color:#1F497D"><a moz-do-not-send="true"
                href="http://www.integralgroup.com/"><span
style="font-size:8.5pt;font-family:"Arial","sans-serif"">www.integralgroup.com</span></a></span><span
              style="font-size:12.0pt;font-family:"Times New
              Roman","serif";color:#1F497D"><o:p></o:p></span></p>
          <p class="MsoNormal"><b><span
                style="font-size:8.0pt;color:#99CC00">DEEP GREEN
                Engineering.<o:p></o:p></span></b></p>
          <p class="MsoNormal" style="margin-bottom:6.0pt"><b><span
style="font-size:8.5pt;font-family:"Arial","sans-serif";color:#99CC00">________________________________<o:p></o:p></span></b></p>
        </div>
        <p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
        <div>
          <div style="border:none;border-top:solid #B5C4DF
            1.0pt;padding:3.0pt 0in 0in 0in">
            <p class="MsoNormal"><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 class="moz-txt-link-abbreviated" href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>
                [<a class="moz-txt-link-freetext" href="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</a>] <b>On
                  Behalf Of </b>Loi Ng<br>
                <b>Sent:</b> Thursday, January 12, 2012 9:38 AM<br>
                <b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:equest-users@onebuilding.org">equest-users@onebuilding.org</a><br>
                <b>Subject:</b> [Equest-users] Help - Modeling VRV-VRF
                System with eQuest<o:p></o:p></span></p>
          </div>
        </div>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal">Hi,<o:p></o:p></p>
        <p class="MsoNormal"><o:p> </o:p></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?<o:p></o:p></p>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal">Thanks!   <o:p></o:p></p>
        <p class="MsoNormal"><o:p> </o:p></p>
        <p class="MsoNormal"><b><span
              style="font-size:14.0pt;font-family:"Bradley Hand
              ITC"">Loi Ng<o:p></o:p></span></b></p>
        <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Arial","sans-serif"">Mechanical
            Engineer</span><span
style="font-size:12.0pt;font-family:"Arial","sans-serif"">,
          </span><span
style="font-size:9.0pt;font-family:"Arial","sans-serif"">LEED<sup>®</sup>
            AP</span><span
style="font-size:12.0pt;font-family:"Arial","sans-serif""><o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#0070C0">Diversified
            Engineering, Inc.<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#0070C0">914
            Silver Spring Avenue, Suite 208<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#0070C0">Silver
            Spring, MD 20190<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#0070C0">Tel:
            301-565-2000 x 234<o:p></o:p></span></p>
        <p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#0070C0">Fax
            301-495-1563 <o:p></o:p></span></p>
        <p class="MsoNormal"><o:p> </o:p></p>
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      <pre wrap="">_______________________________________________
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</pre>
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