Re: [EnergyPlus_Support] Re: Ventilation Requirements per ASHRAE 90.1 Appendix G with a DOAS system

On Tue, Apr 3, 2012 at 6:24 PM, curtisjclark <cjcfromslc@xxxxxxxxx> wrote:

Jim,

Baseline HVAC System is based on ASHRAE 90.1 Appendix G for a VAV with reheat.

Proposed is a DOAS with chilled beam and radiant floors.

Two completely different system.

Curtis

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Pregas Srinivasan <pregas@...> wrote:
>
> For clear picture, is the system type is same in proposed and baseline? Is
> system type is DOAS +VAV. Looks to me two are completely different systems
> to begin with.
>
> PS
>
>
> On Tue, Apr 3, 2012 at 3:47 PM, curtisjclark <cjcfromslc@...> wrote:
>
> > **

> >
> >
> > Jim,
> >
> > For a 100% Outdoor Air System (Proposed) the formula is:
> >
> > Vot = Sum(Voz) 'Sum of the zone
> >
> > For Multi-Zone Recirculating (Baseline) the formula is:
> >
> > Vot = Vou/Ev 'Uncorrected outdoor air rate / Ventilation efficiency
> >
> > If we set the outdoor air requirements at the zone level (Voz) for both
> > models to be equal, Vot of the Baseline will not equal Vot of the Proposed.
> >
> > This may not satisfy requirement of ASHRAE Appendix G3.1.2.6 for
> > ventilation as states:
> >
> > Vot (Baseline) = Vot (Proposed)
> >
> > If we force the issue and set the Vot of Baseline to the Vot of the
> > Proposed, we will not meet the requirement of ASHRAE 62.1 for the Baseline
> > model.
> >
> > In addition, how is EnergyPlus reporting outdoor air because the two
> > reports (Controller:OutdoorAir and Minimum Outdoor Air) are not consistent.
> > I suspect that the Controller:OutdoorAir reports the Vou for a Multi-Zone
> > Recirculating system, not the Vot.
> >
> > Any insights would be appreciated.
> >
> > CURTIS CLARK PE, LEED AP BD+C
> > SUSTAINABILITY SERVICES
> > GSBS Architects
> >
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jim Dirkes" <jim@> wrote:
> > >
> > > Dear Curtis,
> > >
> > > I am not familiar with the report you mention. Where does it come from?
> > And
> > > what does it measure?
> > >
> > > On the other hand, you seem to have answered at least part your own
> > question
> > > by noting that minimums were identical for each of the two systems. Can
> > you
> > > run a 62.1 compliance check? Or get it from the design engineer? To see
> > if
> > > your minimum flows meet the 62.1 requirement?
> > >
> > >
> > >
> > > The Building Performance Team
> > > James V. Dirkes II, P.E., BEMP , LEED AP
> > > 1631 Acacia Drive NW
> > > Grand Rapids, MI 49504
> > > 616 450 8653
> > >
> > >
> > >
> > > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of curtisjclark
> > > Sent: Tuesday, April 03, 2012 12:40 PM
> > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > Subject: [EnergyPlus_Support] Re: Ventilation Requirements per ASHRAE
> > 90.1
> > > Appendix G with a DOAS system
> > >
> > >
> > >
> > >
> > >
> > > Each zone is hardwired using DesignSpecification:OutdoorAir object using
> > > "Flow/Area" values.
> > >
> > > Curtis
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > <mailto:EnergyPlus_Support%40yahoogroups.com> , Vinay Devanathan
> >
> > > <vinay.devanathan@> wrote:
> > > >
> > > > You could hardwire the same OA cfm for each zone to what it is in the
> > > > design case.
> > > >
> > > > On Tue, Apr 3, 2012 at 11:55 AM, curtisjclark <cjcfromslc@> wrote:
> > > >
> > > > > **
> > > > >
> > > > >
> > > > > We are using a DOAS system which delivers 100% outdoor air to the
> > space.
> > > > > In the Baseline model (appendix G), it is a VAV system which delivers
> > > mixed
> > > > > outdoor air with return air.
> > > > >
> > > > > To meet the requirements of ASHRAE 62.1 in the Baseline model, I used
> > > the
> > > > > Ventilation Rate Procedure calculation method to determine the
> > minimum
> > > > > outdoor air by using the Controller:MechanicalVentilation object with
> > > the
> > > > > same ventilation rates as in the DOAS system.
> > > > >
> > > > > The report for "Controller:OutdoorAir" shows the two system have same
> > > > > Minimum Outdoor Air Flow Rate. However, the report "Minimum Outdoor
> > Air
> > > > > During Occupied Hours" shows a 84% reduction in outdoor air.
> > > > >
> > > > > Have I meet the requirements of Appendix G3.1.2.6 for ventilation?
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Vinay Dev
> > > >
> > >
> >
> >
> >
>