<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">Cam:<br><br>Attached is an official interpretation I requested from ASHRAE concerning this issue. In my understanding, the supply fans that do not provide ventilation are not required to run continuously.<br><br>That being said, it is implied that the ventilation air is somehow distributed throughout the occupied space in order to provide air to all the rooms. I was modeling an apartment building with two PTAC systems in each apartment of 4 rooms. The ventilation air was introduced via an outlet over the apartment entry door. It would not be possible to distribute this air to the bedrooms or living room without ductwork. So in this case the PTAC units (2) in each apartment need to run in order to distribute this air, especially if the interior doors are closed.
<br><br>Of course, in the real world the occupants would not leave the PTAC fans running continuously 24 X 7 to distribute this air.<br><br>Has anyone submitted a model to LEED cycling the PTAC fans when ventilation air is provided by another system?<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> Cam Fitzgerald <cam@energyopportunities.com><br><b><span style="font-weight: bold;">To:</span></b> Richard Ellison <REllison@southlandind.com>; James Hess <JHess@tmecorp.com>; Kathryn Kerns
<kathryn.kerns@bceengineers.com>; equest-users@lists.onebuilding.org<br><b><span style="font-weight: bold;">Sent:</span></b> Wed, February 27, 2013 7:40:30 AM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [Equest-users] Baseline PTAC Fan Energy for a Proposed Merv13 + Return Duct System<br></font><br>
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--></style><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Agreed…the conditioning fans can only be cycled if they are not required to distribute the ventilation air from the DOAS.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </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";"> Richard Ellison [mailto:REllison@southlandind.com] <br><b>Sent:</b> Wednesday, February 27, 2013 7:35 AM<br><b>To:</b> Cam Fitzgerald; 'James Hess'; 'Kathryn Kerns'; equest-users@lists.onebuilding.org<br><b>Subject:</b> RE:
[Equest-users] Baseline PTAC Fan Energy for a Proposed Merv13 + Return Duct System</span></p></div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">I agree with your comment that “…suggestion below that the DOAS should be modeled as a process load is inappropriate for the baseline case.” However I have concerns on the final portion of your comment. Most real designs that would be proposed don’t dump OA directly into the space and DO require the terminal fan be running to be operating to distribute OA from the DOAS into the building. In this design you cannot assume the terminal unit is cycled in the proposed case and meet the 62.1 OA requirements.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </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 rel="nofollow" ymailto="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank" href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> [<a rel="nofollow" ymailto="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank" href="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Cam Fitzgerald<br><b>Sent:</b> Wednesday, February 27, 2013 7:27 AM<br><b>To:</b> 'James Hess'; 'Kathryn Kerns'; <a rel="nofollow" ymailto="mailto:equest-users@lists.onebuilding.org" target="_blank"
href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Equest-users] Baseline PTAC Fan Energy for a Proposed Merv13 + Return Duct System</span></p></div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Good morning, all,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">I inadvertently sent the following response only to Kathryn yesterday.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",
"sans-serif";color:#1F497D;">There is no fan power correction available for the baseline residential systems type 1 (PTAC) and type 2 (PTHP). The baseline systems are standardized to establish a benchmark for demonstrating energy savings. If the dormitory includes non-residential spaces (lounges, corridors, and other common areas) with a total area of 20,000 sf or more, then exception (a) to section G3.1.1 would apply and it is appropriate to used an alternate (non-residential) system type for these areas and if the proposed systems are fully ducted return systems with MERV 13 filters, then the adjustment factors for those devices may be applied in the fan power calculations for the non-residential systems.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",
"sans-serif";color:#1F497D;">In light of the suggestion below that the DOAS should be modeled as a process load is inappropriate for the baseline case. When DOAS supply tempered ventilation air directly to the space (e.g. not the return airstream of the unit conditioning the space) the ability to cycle the fans that condition the space to maintain the space temperature is acceptable (these fans are not required to provide ventilation so they do not need to operate continuously). In the Baseline case, the ventilation air is assumed to be delivered through the PTAC/PTHP units so these fans must operate continuously during occupied periods. The savings from cycling the fans in the residential units, the energy recovery, and air-side economizer generally compensates for the additional fan power required for the DOAS system. Note that if the DOAS system were modeled in the baseline case, it is possible that energy recovery would be required and
some of the savings for this measure in the Proposed design would be lost.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Herein lies the value of energy modeling for design decisions…is the fan energy penalty for the DOAS system equal to or less than the potential savings?</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Have a great day!</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p
class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#3D9959;">Cam Fitzgerald</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#3D9959;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#3D9959;">Energy Opportunities/a 7group company</span></p><p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Calibri", "sans-serif";color:#3D9959;">1200 E Camping Area Rd, Wellsville, PA 17365</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </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 rel="nofollow" ymailto="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank" href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> [<a rel="nofollow" ymailto="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank" href="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>James Hess<br><b>Sent:</b> Wednesday, February 27, 2013 12:02 AM<br><b>To:</b> Kathryn Kerns; <a rel="nofollow"
ymailto="mailto:equest-users@lists.onebuilding.org" target="_blank" href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Equest-users] Baseline PTAC Fan Energy for a Proposed Merv13 + Return Duct System</span></p></div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Interesting question about DOAS and the current fan power allowance for system types 1 & 2. I think we very much need an update to Appendix G to account for the fan power requirements of the dedicated outdoor air systems that are (in my opinion) required for unitary type systems such as PTACs as well as the PSZ-ACs. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">I’m in the south, and so we cannot count on simply opening the windows to meet our ASHRAE ventilation requirements, at least not anymore </span><span style="font-size:11.0pt;font-family:Wingdings;color:#1F497D;">J</span><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> (we did exactly that through until ~ 1988 at the school in Louisiana I attending while growing up, at which point we finally got air conditioning and promptly shut the windows).</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">I would argue that a DOAS is necessary in the south to properly provide outside air, while
maintaining acceptable building humidity conditions, for unitary type systems. Anything less is negligent design, in our opinion. However, at the present time, Appendix G assumes that PTACs (or PSZ-ACs) will bring outside air continuously into the zones and cycle the compressor to control room temp while ignoring humidity. You can’t do that in real life. Where we have seen that done, you get condensation and eventually mold, and eventually you get sued.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">I think you have run into a gray area for which there is no good answer currently. Assuming that you are working on a LEED project, you’ll have to hope that you run up against a LEED reviewer that will
exercise good judgment and common sense, and understand that this area is not covered by Appendix G currently and that a reasonable allowance for DOAS fan power should work and should be allowed, since it can be argued that DOAS are required to meet the ASHRAE 62 ventilation requirements.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">The issue is that the 0.3 watts/CFM is only enough fan power allowance to account for a motel “thru the wall” type unit. No external ductwork (supply or return), barely a filter, and certainly no allowance for a DOAS.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">My recommended solution would be to model the DOAS with the same fan power in the Baseline as in the Proposed. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">That’s conservative in my opinion. You aren’t taking credit for any fan energy savings associated with the DOAS, but neither are you unnecessarily penalizing yourself either for something that is required for the Proposed Design.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",
"sans-serif";color:#1F497D;">Regarding AHRI fan power assumptions, I’m not sure about that question. But I did a quick test in eQuest. I built a quick sample model in the DD wizard, selected PTAC, and entered 11 EER for cooling efficiency. I then went to the detailed mode and the EIR conversion was the exact same that eQuest does for any system </span><span style="font-size:11.0pt;font-family:Wingdings;color:#1F497D;">à</span><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> EIR = 0.2580 for EER =11.0. Consequently, we know that eQuest is using the 365 watts/KCFM conversion. But that’s eQuest. I don’t know what AHRI 310 uses for fan power assumption, if anything. I looked into this a while back and I don’t think that eQuest is on the same page with the AHRI fan power assumptions used in the ratings. I could be incorrect, however.
Another thing is that the fan power assumptions used in the AHRI ratings have absolutely nothing to do with the Appendix G fan power requirements. I do know that. I think we need to let eQuest do its thing in the wizard/detailed interface transition, and then go to the detailed interface and change the EIR ourselves to whatever is appropriate, if we can figure out what AHRI is doing regarding fan power assumptions.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Hope this helps! </span><span style="font-size:11.0pt;font-family:Wingdings;color:#1F497D;">J</span><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </span></p><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Regards,</span></p><p class="MsoNormal"><b><span style="font-size:8.0pt;font-family:"Calibri", "sans-serif";color:#339966;"> </span></b></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#339966;">JAH</span></b></p><p class="MsoNormal"><b><span style="font-size:8.0pt;font-family:"Calibri", "sans-serif";color:#339966;"> </span></b></p><p class="MsoNormal"><b><i><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#339966;">James A. Hess, PE, CEM, BEMP</span></i></b><span style="font-size:11.0pt;font-family:"Calibri",
"sans-serif";color:#1F497D;"><br>Energy Engineer<br>TME, Inc.<br>Little Rock, AR</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;">Mobile: (501) 351-4667</span></p></div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri", "sans-serif";color:#1F497D;"> </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 rel="nofollow" ymailto="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank" href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> [<a rel="nofollow"
ymailto="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank" href="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Kathryn Kerns<br><b>Sent:</b> Monday, February 25, 2013 5:57 PM<br><b>To:</b> <a rel="nofollow" ymailto="mailto:equest-users@lists.onebuilding.org" target="_blank" href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> [Equest-users] Baseline PTAC Fan Energy for a Proposed Merv13 + Return Duct System</span></p></div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";">Everyone, I have been modeling some dormitories with a proposed HVAC system involving a DOA with a full exhaust air HX and MERV 13 filters. The puzzle is what to do about the baseline PTAC fan power energy? If I use 0.3 w/cfm as Appendix G
suggests, my PTAC baseline system does not account for a fully ducted return\exhaust or MERV 13 filters. The commercial fan power equation for systems 3-8 accounts for this, but I am not supposed to use that formula for System 1 and 2.</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";">Another puzzle is if I develop an cooling EIR value for my baseline PTAC using the 365 w/kCFM conversion rule and equate that with 0.3 w/cfm, what happened to the other 65 w/kCFM? </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";">Maybe ARI 310/380 doesn’t use 365 w/cfm fan power? I read it and didn’t find any statement regarding fan power requirements, but I assume it works the same as ARI
210/240?</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";">I am wondering if a compromise of </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";"> PTAC fan power = CFM<i>s</i> *0.000365 + A where A= PD*CFM<i>s</i> /4131 and PD = 1.4</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";">might be a reasonable solution?</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",
"sans-serif";"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";"> PTAC fan power = 0.00063 kw/cfm</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";">Does anyone else have experience with this puzzle?</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial", "sans-serif";"> </span></p><p class="section1" style="margin:0in;margin-bottom:.0001pt;"><strong><span style="font-family:"Arial", "sans-serif";color:black;">Kathryn Kerns</span></strong></p><p class="section1"
style="margin:0in;margin-bottom:.0001pt;"><em><b><span style="font-size:11.0pt;font-family:"Arial", "sans-serif";font-style:normal;">Systems Specialist</span></b></em></p><p class="section1" style="margin:0in;margin-bottom:.0001pt;"><em><b><span style="font-variant:small-caps;color:teal;font-style:normal;">BCE</span></b></em><strong><span style="font-size:10.0pt;font-variant:small-caps;color:teal;"> </span><span style="font-variant:small-caps;color:teal;">Engineers, Inc.</span></strong></p><p class="section1" style="margin:0in;margin-bottom:.0001pt;"><strong><span style="font-size:9.0pt;color:black;">| Ph: 253.922.0446 | Fx: 253.922.0896 |</span></strong><span style="font-size:7.0pt;color:black;"> </span></p><p class="MsoNormal"><span style="font-size:13.5pt;font-family:"Arial", "sans-serif";color:black;"> </span></p><p class="MsoNormal"> </p></div></div></div></div>
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