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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">A couple of thoughts -- from your energy end-use breakdown the consumption in the heating season far outweighs the cooling season, so based on your particular situation, the extremes seem to be weighed towards heating.</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt"> </span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">Also your percentage of outside air in the office building is important. If the percentage of outside air isn't very high, most of the heating for the desired MAT comes from the return air. Try using the variable reporting to see how much load is on the preheat coil in your baseline case.</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt"> </span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">Lastly, if your building has major envelope losses, the ERV won't affect the use of your perimeter heating system if one is present, which may be carrying a lot of your heating load.</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt"> </span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">Hope this helps!</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt"> </span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">David</span></font></p><p class="MsoPlainText">
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<p class="MsoNormal"><font size="1" color="black" face="Calibri"><span style="font-size:8.0pt;color:black"> </span></font></p><p class="MsoNormal"><b><font size="2" color="#1f497d" face="Calibri"><span style="font-size:11.0pt;color:#1F497D;font-weight:bold">David S. Eldridge, Jr.</span></font></b><b><font color="#244061"><span style="color:#244061;font-weight:bold">, P</span></font></b><b><font color="#1f497d"><span style="color:#1F497D;font-weight:bold">.</span></font></b><b><font color="#244061"><span style="color:#244061;font-weight:bold">E</span></font></b><b><font color="#1f497d"><span style="color:#1F497D;font-weight:bold">.</span></font></b><b><font color="#244061"><span style="color:#244061;font-weight:bold">, LEED AP BD+C, BEMP, HBDP</span></font></b></p>
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<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> -----Original Message-----</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> From: <a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> [mailto:<a href="mailto:equest-users-">equest-users-</a></span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> <a href="mailto:bounces@lists.onebuilding.org">bounces@lists.onebuilding.org</a>] On Behalf Of Daniel Knapp</span></font></p><p class="MsoPlainText">
<font size="2" face="Consolas"><span style="font-size:10.5pt">> Sent: Thursday, December 09, 2010 11:56 AM</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> To: <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a></span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Subject: [Equest-users] ERV in Ottawa</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Hello,</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> I've been trying to understand how ERV works because I am finding the</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> energy savings to be somewhat less than I had expected. Ottawa has a very</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> cold climate in the winter and a warm, humid climate in the summer and I</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> would expect enthalpy wheels to be a very good energy saving strategy.</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Instead, I am finding that in many cases the building uses more energy and</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> in the best case scenario (OA exhaust DH, mixed air reset, modulate HX) on</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> a VAV system saves only 0.15%. I have built a simple box model with one</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> system in a two-storey office building and tried a number of different</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> control strategies (see attached tables for results). I have tried a VAV</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> and a SZ system. The ERV is able to save marginally more energy in the SZ</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> system, but in neither case are the results what I was expecting.</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> My question is this: are these results to be taken at face value and</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> believed or is there a better way to model ERVs in a Canadian climate? It</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> seems very unlikely to me that ERVs cannot be controlled in such a way as</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> to save significant energy in a climate of extremes. (.inp file attached</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> as well).</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> With thanks and best wishes,</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Dan</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p><p class="MsoPlainText">
<font size="2" face="Consolas"><span style="font-size:10.5pt">> —</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Daniel Knapp, PhD, LEED® AP O+M</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> <a href="mailto:danielk@arborus.ca">danielk@arborus.ca</a></span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Arborus Consulting</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Energy Strategies for the Built Environment <a href="http://www.arborus.ca">www.arborus.ca</a></span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> 76 Chamberlain Avenue</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Ottawa, ON, K1S 1V9</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Phone: (613) 234-7178 ext. 113</span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> Fax: (613) 234-0740</span></font></p>
<p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt">> </span></font></p><p class="MsoPlainText"><font size="2" face="Consolas"><span style="font-size:10.5pt"> </span></font></p></div></body></html>