[Equest-users] Baseline DOAS for LEED

[Nicholas Caton]

Not to derail, but a related tangent:



1.        I cannot find the familiar short hyperlink list of downloadable
EAp2 “credit resources” under the revamped LEED Online site... does this
still exist and if so can anyone walk me through navigating there?

2.       What I did find, clicking around LEED Online while logged in, was
a link suggesting this particular resource (and the older version at that!)
is supposed to cost *$120* ($100 for USGBC members):
http://www.usgbc.org/resources/advanced-energy-modeling-leed-technical-manual

That isn’t a print copy, either…



I’ve collected 2 versions of the “Advanced Energy Modeling for LEED 2009”
technical manual in my references over the years… I don’t recall paying for
them (and some cursory googling shows they can still be easily found
without cost)… Is this a different resource or am I an unwitting pirate?



~Nick

*NICK CATON, P.E.*
*Owner*



*Caton Energy Consulting*
  1150 N. 192nd St., #4-202

  Shoreline, WA 98133
  office:  785.410.3317

www.catonenergy.com



*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On
Behalf Of *Nathan Miller
*Sent:* Tuesday, January 20, 2015 6:47 AM
*To:* Cam Fitzgerald; 'Paul Diglio'; equest-users at lists.onebuilding.org
*Subject:* Re: [Equest-users] Baseline DOAS for LEED



I would second that thought. I’ve worked on projects where a gas-fired unit
provides neutral air (DOAS) to apartment unit WSHP or VRF. You start
getting into some weird warping of results if you compare that system to
PTAC or PTHP baseline (heat pump heating uses less site energy than furnace
heating, but natural gas tends to have much lower energy cost). Anyway, in
the past I’ve successfully argued that G3.1.2.3 provides the basis that the
tempering system should be modeled in the proposed case, thus you get more
of an apples-to-apples comparison (gas unit picks up the vent load, heat
pumps pick up the skin load).

*G3.1.2.3 Preheat Coils. If the HVAC system in the proposed design has a
preheat coil and a preheat coil can be modeled in the baseline system, the
baseline system shall be modeled with a preheat coil controlled in the same
manner as the proposed design.*



I concede that a gas-fired furnace IS NOT a preheat coil, but it is
essentially serving the same purpose in many cases (heat pumps can’t handle
the incoming temp of the OA if it was delivered directly to the units…). At
any rate, the GBCI reviewers have accepted this rationale in the past, but
it in no-way ensures they will rule that way in the future.



As Cam points out, don’t double count fan energy. The 0.3 W/CFM for
PTHP/PTACs is total system fan energy, and in the projects I worked on I
zeroed out the fan power on the baseline DOAS unit.





*Nathan Miller, PE, LEED AP BD+C** – **Mechanical Engineer/Senior Energy
Analyst*

*RUSHING* | *D* 206-788-4577 | *O* 206-285-7100

*www.rushingco.com <http://www.rushingco.com/>*



*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
<equest-users-bounces at lists.onebuilding.org>] *On Behalf Of *Cam Fitzgerald
*Sent:* Tuesday, January 20, 2015 8:19 AM
*To:* 'Paul Diglio'; equest-users at lists.onebuilding.org
*Subject:* Re: [Equest-users] Baseline DOAS for LEED



Paul,



I didn’t see a response to your question. Although I cannot address the
issues raised by your reviewer, you may find it helpful to review the
Advanced Energy Modeling for LEED 2009 (free resource available under
project resources in LEED online). Table 3.1 under “Common Errors
“addresses this issue (page 33 in the September 2011 edition, 4th bullet)
which includes an exception for high-rise residential projects in hot,
humid climates. Note that this exception still prohibits any extra fan
power for this additional system in the Baseline case. Since your VRF units
will typically have very low fan power, the penalty for the additional
ventilation system fan power should be minimized and easily recaptured by
other efficiency improvements in the design.



Hope this helps,





Cam Fitzgerald



Energy Opportunities/a 7group company





*From:* Equest-users [mailto:equest-users-bounces at lists.onebuilding.org
<equest-users-bounces at lists.onebuilding.org>] *On Behalf Of *Paul Diglio
*Sent:* Friday, January 16, 2015 9:32 AM
*To:* equest-users at lists.onebuilding.org
*Subject:* [Equest-users] Baseline DOAS for LEED



Hi Folks:



I submitted a model to LEED of a 7 story apartment building.  In the
proposed design a DOAS was specified because natural ventilation could not
be provided per 62.1 due to the dimensions of the apartments.



Another issue is that the HVAC systems are Daikin VRF and they could not be
supplied with directly ducted outside air due to the installation locations
and the VRF cassettes do not have a fitting for an outside air duct.



The GBCI came back and said I could not include the DOAS in the baseline
model.  The baseline HVAC system per 90.1 requirements are PTHP.  I
responded to them twice with various reasons the DOAS needed to be included
in the baseline but they won't budge.



Has anyone successfully addressed this type of design?



Thank you,



Paul Diglio



87 Fairmont Avenue
New Haven, CT 06513
203-415-0082
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