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RE: [EnergyPlus_Support] Re: system 8 - ASHRAE 90.1 G





Dante,

When pursuing the credit for 30% additional outdoor air, the Baseline model must use outdoor air amounts consistent with ASHRAE 62.1.  These values are set in DesignSpecification:Outdoor air, which is the method I normally use.  I think you can also use Sizing:System, System Outdoor Air Method (but I have not used that method)

Controller:OutdoorAir, Minimum Outdoor Air Flow Rate sets the minimum OA flow rate for all periods when the fan is operating unless you override it with the Minimum Outdoor Air Schedule Name or Minimum Fraction of Outdoor Air Schedule Name in the same object (Controller:OutdoorAir).  Study the Input Output Reference for that object to understand how each part works.

 

James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653

 

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of andresdagm
Sent: Wednesday, October 10, 2012 12:56 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: system 8 - ASHRAE 90.1 G

 

 

Thank you James,

just only one more question about the question below (bold type)

Dante García


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "andresdagm" <andresdagm@...> wrote:
>
> i understand better, thank you
>
> It is g.3.1.2.8, i forget to writte a 1 one.
>
> i am pursuing the LEED credit for 30% additional outdoor air, what i see is that according to g3.1.2.5 the minimun ventilation outdoor air rate need to be the same in both models (it is to dont claim for credit giving less outdoor air rate). Is need to be setup in Controller:OutdoorAir Minimun Outdoor Air flow rate?.
>
> Regarding about the schedule for HVAC Fan, how may I do if i want that the Air Lop (VAV) comply with minimun air flow rate and cooling capacity on ocupied hours. (What i think is if I setup the minimun outdoor air flow rate in each AirLoop, it will work with at least that flow rate, isn't it?)
>
> Thank you again
> I am learning a lot about ASHRAE
> That is good
>
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Jim Dirkes jim@ wrote:
> >
> > Dear Dante,
> >
> > * Normally (almost always) it is correct to size for the sensible load.
> >
> > * It is also correct that the outdoor air rates must normally be the same for both the Baseline and Proposed models. There are exceptions, however, if you are using Demand Controlled Ventilation in the Proposed design. If you are pursuing the LEED credit for 30% additional outdoor air, the models will also differ.
> >
> > * I do not know what you are referring to for "g.3.2.8", so you'll have to explain more clearly.
> >
> >
> > James V Dirkes II, PE, BEMP, LEED AP
> > www.buildingperformanceteam.com<http://www.buildingperformanceteam.com/>
> > Energy Analysis, Commissioning & Training Services
> > 1631 Acacia Drive, Grand Rapids, MI 49504 USA
> > 616 450 8653
> >
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of andresdagm
> > Sent: Thursday, October 04, 2012 4:11 PM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: [EnergyPlus_Support] Re: system 8 - ASHRAE 90.1 G
> >
> >
> >
> > thank you james
> > i understand, how need to be set the Type of load to size on (sensible/air requeriment)?. i think that it need to be sensible, because the air loop will meet the cooling load, but how about the renovation of air? ASHRAE said in g3.1.2.5 that minimun outdoor air ventilation rates need to be the same in both, proposed and baseline.
> >
> > As you said, Design outdoor air flow rate will be autosize, before considering the requeriments that said g.3.2.8 how you described below.
> > i am in troubles to understand it.
> > thank you again
> > Dante
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>, Jim Dirkes <jim@<mailto:jim@>> wrote:
> > >
> > > 1. Keep in mind that there is a normal requirement for a Baseline system to be modeled as one system per floor. (That probably won't affect your outcome very much, but it may save trouble from the LEED reviewer.)
> > >
> > > 2. The Baseline airflow will not be the same as Proposed. Baseline systems must be sized with 11.1C delta temperature and Proposed systems are often sized differently. In addition the loads will differ for Baseline / Proposed due to different wall and glazing. Both of these factors will combine to produce different airflows.
> > >
> > > 3. Cooling load is met exclusively by the Air Loop discharge temperature (Room temp of ~ 23C - 11.1C = ~12.2C discharge temp)
> > >
> > >
> > >
> > > James V Dirkes II, PE, BEMP, LEED AP
> > > www.buildingperformanceteam.com<http://www.buildingperformanceteam.com/>
> > > Energy Analysis, Commissioning & Training Services
> > > 1631 Acacia Drive, Grand Rapids, MI 49504 USA
> > > 616 450 8653
> > >
> > > From: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>] On Behalf Of andresdagm
> > > Sent: Thursday, October 04, 2012 10:48 AM
> > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > > Subject: [EnergyPlus_Support] Re: system 8 - ASHRAE 90.1 G
> > >
> > >
> > >
> > > no, i aren't. I am modeling baseline system 8.
> > > I use AirTerminal:SingleDuct:ParallelPIU:Reheat in each zone. About the AirLoop, which use VAV, it need to be made just only one like in my proposed design, the think that i dont understand is this: AirLoop whit the same air flow than in my proposed, acording to ASHRAE, this AirLoop will contain the water coil that will suply cool air, isn't it?
> > > Also, In each zone i will have a AirTerminal:SingleDuct:ParallelPIU:Reheat, So, in each zone i will only sep up this equipment to meet the heating load.
> > > what about coolin load, just the coil that i have in the
> > > Air Loop willl meet my confort temperture?
> > > thank you
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com><mailto:EnergyPlus_Support%40yahoogroups.com>, Jim Dirkes <jim@<mailto:jim@>> wrote:
> > > >
> > > > Are you modeling System #6?
> > > > If so , just make an Air Loop which uses VAV and AirTerminal:SingleDuct:ParallelPIU:Reheat in each zone.
> > > >
> > > > James V Dirkes II, PE, BEMP, LEED AP
> > > > www.buildingperformanceteam.com<http://www.buildingperformanceteam.com/>
> > > > Energy Analysis, Commissioning & Training Services
> > > > 1631 Acacia Drive, Grand Rapids, MI 49504 USA
> > > > 616 450 8653
> > > >
> > > > From: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com><mailto:EnergyPlus_Support%40yahoogroups.com> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com><mailto:EnergyPlus_Support%40yahoogroups.com>] On Behalf Of andresdagm
> > > > Sent: Thursday, October 04, 2012 9:43 AM
> > > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com><mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > Subject: [EnergyPlus_Support] Re: system 8 - ASHRAE 90.1 G
> > > >
> > > >
> > > >
> > > > Any help?
> > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com><mailto:EnergyPlus_Support%40yahoogroups.com><mailto:EnergyPlus_Support%40yahoogroups.com>, "andresdagm" <andresdagm@<mailto:andresdagm@>> wrote:
> > > > >
> > > > > good day,
> > > > >
> > > > > i am modeling a base line for LEED certification.
> > > > >
> > > > > this model use a VAV systems and PIU with REheat
> > > > > a have model it, my problems is may i connect each zone to a central air loop, because i my proposed model I am using a fan coil in each zone and a central air loop that supply air to each zone.
> > > > >
> > > > > thank you for youe help
> > > > >
> > > >
> > >
> > .
> >
>



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