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<DIV>Short answer: Yes. </DIV>
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<DIV>The temperature & humidity of the dummy/duct zone is used in place of the outside air to the system/zones which include the OA-FROM-SYS command. With no loads in this zone, its conditions should be the same as the supply air. To simulate proper dehumidification when modeling a DOAS as PSZ, the zone cooling setpoint schedule would need to be set to 55F or so, and the real DOAS capacities should probably be entered manually. Other model system/zone combinations generally better represent actual DOAS operation, and should be provided as discussion or example by the program authors.</DIV>
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<DIV>Fred Porter</DIV>
<DIV>AEC</DIV>
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<DIV><BR>>>> "Kevin Kyte" <kkyte@robsonwoese.com> 1/8/2008 10:02 AM >>><BR></DIV>
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<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">I understand that doe2.2 cannot accurately model energy recovery in these conditions. Would the zones receiving the outside air from the system at least receive the same tempered air as the dummy zone in the system? <o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'">Kevin<o:p></o:p></SPAN></P>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 11pt; COLOR: #1f497d; FONT-FAMILY: 'Calibri','sans-serif'"><o:p> </o:p></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><B><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">From:</SPAN></B><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'"> Fred Porter [mailto:FPorter@archenergy.com] <BR><B>Sent:</B> Friday, December 14, 2007 3:30 PM<BR><B>To:</B> bldg-sim@lists.onebuilding.org; Kevin Kyte<BR><B>Subject:</B> Re: Equest: ERU with added heat and vfd's<o:p></o:p></SPAN></P></DIV></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">Folks;<o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">Whatever else maybe wrong or right with these approaches, eQ/DOE-2.2 cannot generally correctly model energy recovery in the OA-FROM-SYS. This is because the exhaust/return air to the OA-FROM-SYS in a DOE-2 model is NOT from the occupied spaces, it is from the dummy/duct zone, which should never be at the room/return air conditions in either the model or reality. (It will usually be substantially cooler.) Too bad, because many real DOAS systems, (which would appear to be best represented with DOE-2's OA-FROM-SYS) include heat recovery and pre-conditioning.<o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'"> <o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">Anyone know if any of the other "typical" simulation programs (TRACE, E+) represent a DOAS supplying zonal HVAC more correctly? Obviously one could model them in TRNSYS, and IES-VE.<o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'"> <o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">Fred Porter<o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">AEC<o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'"> <o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'">P.S. I did actually once whip up a convoluted DOE-2.2 "workaround" for this arrangement. But I will not post it here because it really does not qualify as "simulation;" calling it a brittle kludge would be charitable. <o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'"> <o:p></o:p></SPAN></P></DIV>
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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Tahoma','sans-serif'"><BR>>>> "Kevin Kyte" <kkyte@robsonwoese.com> 12/14/2007 11:59 AM >>><BR><BR><BR>I am attempting to model an energy recovery unit (ERU) supplying outside air<BR>for 5 air handling units (AHUs). I have attempted to do this thus far by<BR>making the ERU a separate system PSZ with dumbo zone and the AHUs use ERU<BR>for OA-FROM-SYSTEM. <BR><BR><BR><BR>The problem lies within energy recovery capacities, the ERV report<BR>capacities are nowhere near as high as the designed energy recovered so the<BR>coiling coil is undersized and I am getting a lot of inadequate cooling<BR>capability warnings. The ERU has an additional gas furnace but no<BR>additional cooling.<BR><BR><BR><BR>This is where I may be getting it mixed up because I set the<BR>COOLING-SCHEDULE flagged to off for the entire year and I end up with no<BR>energy recover on the cooling side. Even if I were to change the ERU to<BR>type PVAVS or SZRH it shows minimal or no recovery. How should I schedule<BR>cooling?<BR><BR><BR><BR>Are any other parameters that I may be missing, I have included the enthalpy<BR>wheel effectiveness and a control sequence. How about humidity controls?<BR>Since this suppose to be a LEED certified building will ECMs be necessary?<BR>Or should I go back to doing individual heat recovery for each AHU? So many<BR>questions.<BR><BR><BR><BR>Kevin<BR><BR><BR><BR>From: Brian Fountain [mailto:bfountain@greensim.com] <BR>Sent: Wednesday, November 21, 2007 11:27 AM<BR>To: kkyte@robsonwoese.com; BLDG-SIM@gard.com<BR>Subject: RE: [BLDG-SIM] Equest: ERU with added heat and vfd's<BR><BR><BR><BR>The way I would do it is to use the OA-FROM-SYSTEM keyword and add the ERU<BR>as a separate system with ventilation heat recovery. In this way, you can<BR>define the heat recovery and power and flow characteristics of the ERU<BR>explicitly. <BR><BR><BR><BR>I usually do this by first creating a very small (1 sq-ft) dummy space, then<BR>a dummy thermal zone for that space. Then, create the ERU as a 100% OA<BR>constant volume system serving that thermal zone. Now comes the fun part.<BR>You close eQUEST, open the .inp with a text editor and cut the new system<BR>and all its keywords from the bottom of the list of systems and paste it to<BR>the top of the system list. If you don't do this, when you run the<BR>simulation, it will complain that the OA-FROM-SYSTEM system referenced does<BR>not precede the current system and will abort the sim. Now, reopen eQUEST<BR>and in your 6 systems, use the OA-FROM-SYSTEM keyword on the system, OA tab<BR>to define that the ventilation air is coming from your ERU. <BR><BR><BR><BR>Hope this helps.<BR><BR><BR><BR>-----Original Message-----<BR>From: BLDG-SIM@gard.com [mailto:BLDG-SIM@gard.com] On Behalf Of Kevin Kyte<BR>Sent: November 21, 2007 10:55 AM<BR>To: BLDG-SIM@gard.com<BR>Subject: [BLDG-SIM] Equest: ERU with added heat and vfd's<BR><BR><BR><BR>Simulating an energy recovery unit which serves six air handling units. I<BR>suppose this is simply enough, I split the total cfm into percentages for<BR>each unit and incorporate into each unit's heat recovery, yes? Is there any<BR>way to include additional heat from the energy recovery unit? Perhaps split<BR>the total heat into percentages and include this in each unit's heating<BR>capacity. How about variable frequency drives on supply and exhaust fans<BR>for energy recovery unit? Perhaps this could be modeled as a 10% reduction<BR>in the fan power similar to occupancy sensors on lights? Regarding LEED,<BR>would usgbc need a credit interpretation request for something like this or<BR>maybe just mentioning it as a default overridden in the submittal would<BR>suffice. Would anyone who has encountered this care to chime in? Any<BR>suggestions would be forthcoming. Thank you.<BR><BR><BR><BR>Kevin Kyte, LEED AP<BR><BR>Jr. Mechanical Engineer<BR><BR>RobsonWoese, Inc.<BR><BR>T: 716-636-1800<BR><BR>F: 716-636-1856<BR><BR><BR><BR>From: BLDG-SIM@gard.com [mailto:BLDG-SIM@gard.com] On Behalf Of Zhen Tian<BR>Sent: Tuesday, November 20, 2007 5:38 PM<BR>To: BLDG-SIM@gard.com<BR>Subject: [BLDG-SIM] add ceiling in eQUEST<BR><BR><BR><BR>Dear all,<BR><BR>When I model a one-floor building in eQUEST, I found that adding the "lay-in<BR>acoustic tile" ceiling (no insulation added) will cause the peak load<BR>through roof to zero. When eliminate the ceiling, a large part of the<BR>building heat flow will go through the roof.<BR><BR>I also tried several buildings. When added ceiling, then the heat flow<BR>through roof turns to zero. Does anyone have an idea why this happens? <BR><BR>Thanks a lot.<BR><BR>Regards,<BR><BR>David<BR><BR> <BR><BR> _____ <BR><BR>Be a better sports nut! Let your teams follow you with Yahoo Mobile. Try<BR><<A href="http://us.rd.yahoo.com/evt=51731/*http:/mobile.yahoo.com/sports;_ylt=At9_qD">http://us.rd.yahoo.com/evt=51731/*http:/mobile.yahoo.com/sports;_ylt=At9_qD</A><BR>KvtAbMuh1G1SQtBI7ntAcJ > it now.<BR><BR><BR><BR>==================<BR>You received this e-mail because you are subscribed <BR>to the BLDG-SIM@GARD.COM mailing list. 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