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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi Manuela,<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'>Following is a plot of OADB (red) vs. interior space temperature (blue) for the C-DUMMY zone, for the first ~500 hours of the simulation:<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:black'><img width=962 height=241 id="Chart_x0020_4" src="cid:image002.png@01D1A086.5D092FC0"></span><span style='color:black'><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'>Note a few things:<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>Every hour your space temperature is bouncing like a pinball around your setpoint (40F), oftentimes beyond the throttling range (registering an unmet hour). <o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>While the hourly need for heating remains constant (OA remains below 40F), the “pendulum” swing hour by hour gradually lessens over time.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>When OA crosses the setpoint line (>40F), the resulting swing after it drops again can be either mitigated or exacerbated depending on whether the system was trying to heat in that hour. Kinda like jumping on a trampoline out of sync with a friend – depending on timing, you may lose all momentum or you may rocket into the sky! <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'>Now let’s look at the “whole year” picture for the same plot:<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>You can more clearly see the above behavior repeating through the winter months<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l1 level1 lfo2'><![if !supportLists]><span style='color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>The pendulum swinging is actually worst in the spring/autumn (when OA more frequently crosses the 40F line), but the general hourly behavior (hot/cold/hot/cold) doesn’t really ever go away…<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'><img width=974 height=244 id="Chart_x0020_2" src="cid:image004.png@01D1A086.5D092FC0"></span><span style='color:#1F497D'><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'>These behaviors led me to guess (correctly) that you have little (zero) thermal mass in your dummy zones. Freezing air comes in one hour so the system turns on, the space gets overheated next hour the next so system turns off, rinse and repeat.<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 tried making this tracked dummy zone bigger (100ft x 100ft), adding a single interior wall to the bottom (of type INTERNAL so no thermal connections elsewhere in your model), and assigning a library LAYERS construction (any of the ASHRAE Concrete walls should do) to effectively give it some thermal mass to store heat hour by hour. The result is zero unmet hours (for that zone) and this “bouncing” behavior goes away:<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'><img width=962 height=241 id="Chart_x0020_5" src="cid:image010.png@01D1A086.5D092FC0"></span><span style='color:#1F497D'><o:p></o:p></span></p><div><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>After fixing the flailing dummy zone temps by adding thermal mass, you may wish to re-evaluate whether the heatpumps are receiving tempered OA. <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’m not aware of a particularly simple/direct way to do so short of crunching a bunch of custom hourly SYSTEM and ZONE outputs to work it backwards from the coil leaving temperature (any tips from the crowd that uses dummy zone workarounds for DOAS more regularly?)… however if I more simply set you’re the above “DUCT” system to SUM & remove the associated OA-FROM-SYSTEM inputs (effectively pushing all required OA conditioning back onto the “receiving” heatpump systems – whose heating capacity inputs are fixed/specified), I observe the associated spaces shift from “many” annual unmet heating hours to “many more…” This suggests (A) the contributions of OA-FROM-SYSTEM tempering <i>exist</i> and are at least <i>mitigating</i> the situation, and (B) you probably have issues beyond OA temperatures to deal with.<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'>A few other things caught my eye along the way:<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo3'><![if !supportLists]><span style='font-family:Symbol;color:#1F497D'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>Like the dummy zone discussed above, ALL of your assigned envelope constructions & floors are “massless” (defined with the U-value specification method in lieu of layers). I expect if we plot more zone temperatures we would find more pinball behavior! Switching to constructions with thermal mass is probably going to help reduce unmet hours altogether.<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo3'><![if !supportLists]><span style='font-family:Symbol;color:#1F497D'><span style='mso-list:Ignore'>·<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='color:#1F497D'>I notice substantial unmet hours outside of the dummy zones, and that you have chosen to group zones with likely dissimilar load profiles under PVVT systems – bear in mind the typical relationship for the control zone vs. the “slave” zones when evaluating whether those unmet hours are meaningful… you might want to re-evaluate your system quantities and/or whether a few thermostat schedules should be removed where they don’t exist in the actual design.<o:p></o:p></span></p><p class=MsoListParagraph><span style='color:#1F497D'><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 hope that helps you and others!<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'>~Nick<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#3A7A46'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#3A7A46'>------------------------------------------------------------------------------------------------------------------------------<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-family:"Arial","sans-serif";color:#3A7A46'>Nick Caton, P.E.</span></b><span style='color:#3A7A46'><o:p></o:p></span></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=724 style='width:543.0pt;border-collapse:collapse'><tr><td width=230 valign=top style='width:172.3pt;padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> Senior Energy Engineer</span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> Energy and Sustainability Services</span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> North America Operations</span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> Schneider Electric</span><span style='color:#1F497D'><o:p></o:p></span></p></td><td width=291 valign=top style='width:218.3pt;padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>D </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>913.564.6361 </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>M </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>785.410.3317 </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>E </span><span style='color:#1F497D'><a href="mailto:nicholas.caton@schneider-electric.com"><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>nicholas.caton@schneider-electric.com</span></a></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>F </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>913.564.6380</span><span style='color:#1F497D'><o:p></o:p></span></p></td><td width=203 valign=top style='width:152.4pt;padding:0in 0in 0in 0in'><p class=MsoNormal align=right style='text-align:right'><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>15200 Santa Fe Trail Drive<br>Suite 204<br>Lenexa, KS 66219<br>United States</span><span style='color:#1F497D'><o:p></o:p></span></p></td></tr><tr style='height:4.0pt'><td width=724 colspan=3 valign=top style='width:543.0pt;padding:0in 0in 0in 0in;height:4.0pt'><p class=MsoNormal style='mso-line-height-alt:4.0pt'><span style='color:#3A7A46'><img border=0 width=722 height=49 id="Picture_x0020_3" src="cid:image001.png@01D1A066.FA87B0C0" alt="cid:image001.png@01D189AB.58634A10"></span><span style='color:#3A7A46'><o:p></o:p></span></p></td></tr></table><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></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"'> Equest-users [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Manuela Mengue via Equest-users<br><b>Sent:</b> Wednesday, April 27, 2016 7:51 AM<br><b>To:</b> equest-users@lists.onebuilding.org<br><b>Subject:</b> [Equest-users] Electric duct heaters<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dear All,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Water source heat pumps are serving spaces in the cellar and first floor that are of concern for this model. Please review the eQuest energy model attached. I am trying to find the appropriate way to model <span style='color:black'>two </span>electric duct heaters <span style='color:black'>and outside air fans on the cellar & first floors </span>mainly utilized to provide outside air to <span style='color:black'>the WSHP </span>units <span style='color:black'>o</span>n the<span style='color:black'>se </span>floor<span style='color:black'>s</span>. <span style='color:black'>The electric duct heaters heat the outside air from 0F to 40F (cellar) or 60F (first floor). </span>The temperature of entering outside air should be 40F for units “C EXERCISE ROOM SYS”, “C AC SYS” AND “C SCREEN ROOM SYS” on cellar floor, and 60F for units “1 LOUNGE”, “1 LOBBY SYS” and “1 CORR BIKE MAIL SYS” on first floor. I created two heating and ventilation systems “C DUCT HEATER” and “1 DUCT HEATER”, and fixed the heating set point temperatures to 40F and 60F respectively. I also created and assigned dummy <span style='color:black'>zones</span> with no internal gains to these systems. After simulation, I am getting extremely high heating unmet hours for the dummy <span style='color:black'>zones</span>, plus the zones served by the above systems do not seem to receive outside air at the appropriate temperature. I am wondering if some inputs in my model are incorrect. If possible, can anyone please indicate how this design strategy should be modeled and the resulting issues addressed ?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='background:white'><span style='color:black'>Thank you,<o:p></o:p></span></p><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Futura Md BT";color:black'><o:p> </o:p></span></p><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Futura Md BT";color:black'>Manuela </span><span style='font-size:20.0pt;font-family:"Futura Md BT";color:black'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><br>______________________________________________________________________<br>This email has been scanned by the Symantec Email Security.cloud service.<br>______________________________________________________________________<o:p></o:p></span></p></div></body></html>