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[EnergyPlus_Support] Re: Fresh Air Issues

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Fresh Air Issues
From: "ntraughpee" <matthew.sverre.anderson@xxxxxxxxx>
Date: Tue, 01 Nov 2011 20:48:55 -0000
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Awesome, thank you sir

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Griffith, Brent" <brent.griffith@...> wrote:
>
> The way to get 100% OA in an AirLoopHVAC is to use the Minimum Fraction of Outdoor Air Schedule in the Controller:OutdoorAir object, and set it to 1.0 all the time.
> 
> 
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of ntraughpee
> Sent: Tuesday, November 01, 2011 12:29 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Fresh Air Issues
> 
> 
> 
> PS: and I don't just mean this system but any system?
> 
> I work for a University and we have a lot of labs which require 100% FA that in the future we will likely want to model and I am currently at a loss as how to arrange the model to show this.
> 
> I have tried searching but can't seem to find an acceptable answer.
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>, "Jim Dirkes" <jim@> wrote:
> >
> > Dear Matthew,
> >
> > Thinking about it more..
> >
> > The AirTerminal:DualDuct:ConstantVolume object should do the trick for you.
> > The physics are all the same as a multi-zone system. Check out the IO
> > Reference, pages
> >
> > . 569 (610 in the PDF) for air loop node creation
> >
> > . 1038 (1079) for the AirTerminal description
> >
> >
> >
> > This type of system will often run with a constant hot deck discharge temp
> > and also a constant cold deck discharge temp year 'round. The hot deck
> > sometimes is allowed to be just mixed air in the warm weather months (when
> > no real heat is required. The cold deck becomes just mixed air in the cold
> > weather months. Although the deck discharge temps can remain constant, they
> > are sometimes reset based on outdoor air temps.
> >
> >
> >
> > There are several example files which should be helpful (I have not looked
> > at them, however)
> >
> > . DDAutoSize.idf
> >
> > . DualDuctConstVolDamper.idf
> >
> > . DualDuctConstVolGasHC.idf
> >
> >
> >
> > p.s., I embedded a .png earlier; maybe it got stripped out.
> >
> > 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%40yahoogroups.com>
> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>] On Behalf Of ntraughpee
> > Sent: Tuesday, November 01, 2011 10:33 AM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > Subject: [EnergyPlus_Support] Re: Fresh Air Issues
> >
> >
> >
> >
> >
> > Your document wasn't attached (or I am too stupid to see it!) but I looked
> > at the ASHRAE handbook and yes it is a multi-zone air handler with a
> > constant volume fan and the dampers change position to alter the % of air
> > flow to each zone. However, there is no return air system, no fan, no
> > economizer (etc..)
> >
> > It is currently 100% Outside Air, and I am looking for a good way to model
> > such a system and then compare it to one with return air so I can calculate
> > savings.
> >
> > Hopefully this makes sense.
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com> , "Jim Dirkes" <jim@>
> > wrote:
> > >
> > > Dear Matthew,
> > >
> > >
> > >
> > > I'll bet you are looking at a multi-zone air handler, something like the
> > > image below (courtesy ASHRAE Handbook 2008, p4.13). That should be a
> > system
> > > E+ can handle, but I cannot find any objects that look appropriate or
> > > mention of it in the IO Reference.
> > >
> > > I've never had to model one (though I've designed them), so perhaps
> > someone
> > > else in the forum has tried it?
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > 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%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com> ] On Behalf Of ntraughpee
> > > Sent: Monday, October 31, 2011 4:13 PM
> > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > Subject: [EnergyPlus_Support] Re: Fresh Air Issues
> > >
> > >
> > >
> > >
> > >
> > > This is a real building with a constant volume air handler and three
> > dampers
> > > that proportionally modulate air flow to the different zones. I use the
> > term
> > > "proportionally modulate" in pretty loose terms there since the system is
> > > pneumatic, we have no plans, and I was born after dinosaurs walked the
> > Earth
> > > so it is difficult for me to figure out exactly how the system operates.
> > (By
> > > proportionally modulate it looks like the dampers are linked in such a way
> > > that 33% air flow goes to one zone, 33% to the 2nd, 33% to the 3rd and if
> > > one zone needs more it can shift to lets say 60%, 20%, 20%).
> > >
> > > One of my ideas is to put in some sort of return air system to cut down on
> > > the energy consumption which is currently 445 kBTu/SF. Obviously we will
> > > update to electronic controls and eliminate leaky valves etc...
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com> , YuanLu Li <yli006@>
> > > wrote:
> > > >
> > > >
> > > > Are you talking about a real building or something you dream up in your
> > > IDF?
> > > > Dr. Li
> > > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx<mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > From: matthew.sverre.anderson@
> > > > Date: Fri, 28 Oct 2011 20:49:18 +0000
> > > > Subject: [EnergyPlus_Support] Fresh Air Issues
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Hey Everybody,
> > > >
> > > >
> > > >
> > > > So I am currently trying to model a building for energy analysis. One
> > > glaring deficiency is that the building only pulls 100% fresh air, and
> > there
> > > is no return air ductwork or economizer. This is obviously a glaring issue
> > > that I want to fix, however I am currently at a loss as exactly how to do
> > > this or if there are any work-arounds that will let me do it in a an easy
> > > manner.
> > > >
> > > >
> > > >
> > > > Basically, my initial plan was to try to fenagle something in HVAC
> > > Templates where I set the fan CFM @ what it is measured at (ie 10,000 CFM)
> > > then set the max/min outdoor air @ the same CFM rate so that EnergyPlus is
> > > just assuming 100% FA all day, every day (such that it would be leaving
> > via
> > > the relief air ductwork). Is this the best way to do it? In reality there
> > is
> > > no relief air ductwork since the system just pressurizes the building and
> > > forces air out of the cracks etc...
> > > >
> > > >
> > > >
> > > > I was then working on the .expidf and was curious if anybody had a good
> > > way of doing this using the AirLoop HVAC?
> > > >
> > > >
> > > >
> > > > Basically: what is the best way to model a system with 100% fresh air
> > and
> > > no return ductwork/relief ductwork
> > > >
> > >
> >
>




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References:
- RE: [EnergyPlus_Support] Re: Fresh Air Issues
  - From: Griffith, Brent

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