[Equest-users] Ventilation for System 7-Ashrae-2007-Baseline

via Equest-users equest-users at lists.onebuilding.org
Wed Sep 14 10:52:35 PDT 2016

Hi Kumar, 


I think you've answered your query already...


For LEED specifically, the baseline ventilation rates should match the
minimums documented under IEQp1 (i.e. 62.1).  I would have those minimum
OA quantities delivered during all occupied (system ON) hours.  The
exception in the baseline case would be for any spaces for which DCV is
already required under 6.4 provisions (assembly, conference rooms,
auditoriums, and similar areas will pass the occupancy density
threshold).  If DCV is required under 6.4, model that in both baseline
and proposed cases in a consistent fashion.


One point of confusion in this matter might lie in your phrasing "my
proposed building uses 100% fresh air..."  I would interpret that to
mean you have airside economizer capacity capable of delivering 100% of
design airflow rates, but that should have zero direct bearing on your
baseline case systems.  Baseline system economizer function (if
occurring at all) should be determined in accordance with G3.1.2.6 & 7.


Hope that helps you keep rolling!







Nick Caton, P.E.

  Senior Energy Engineer
  Energy and Sustainability Services
  Schneider Electric

D  913.564.6361 
M  785.410.3317 
E  nicholas.caton at schneider-electric.com
<mailto:nicholas.caton at schneider-electric.com> 
F  913.564.6380

15200 Santa Fe Trail Drive
Suite 204
Lenexa, KS 66219
United States




From: Equest-users [mailto:equest-users-bounces at lists.onebuilding.org]
On Behalf Of Saurabh Kumar Srivastava via Equest-users
Sent: Wednesday, September 14, 2016 6:26 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Ventilation for System 7-Ashrae-2007-Baseline


Hi Guys!


I'm trying to model the Ventilation on the Baseline System 7(VAV with
Reheat) based on Ashrae-2007.


My Proposed building uses 100% Fresh Air with  Demand Control
Ventilation and Heat Recovery wheels.

Most of the office spaces inside have an area greater than 500sqft.


I'm trying to understand how the Ventilation  rate for baseline for such
a building should be modelled.

-Would the Baseline have same Ventilation as the Proposed   OR

-Would I have to use Ashrae 62.1 Ventilation (Fresh) Air rates for all
zones/Rooms  ?


Studying :-

The Table 1.4 and Appendix G of Ashrae 90.1 says:

-Demand control ventilation is modeled in the Baseline case for all
spaces larger than 500 square feet that have a design occupancy for
ventilation of greater than 40 people per 1,000 sf of floor area (except
for spaces served by Baseline systems that do not have one of the
following: an air-side economizer, automatic modulating control of the
outdoor air damper, or a design outdoor airflow of greater than 3,000
cfm) per G3.1.2.5 /


-The minimum outdoor air ventilation rates (including infiltration) are
the same for the Proposed and Baseline building designs consistent with
Section G3.1.2.5 unless demand control ventilation is modeled for
credit, in which case, the ASHRAE 62.1 minimum ventilation rates from
IEQp1 are modeled for all Baseline systems where credit is taken for
demand control ventilation.


Best Regards



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