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[EnergyPlus_Support] Re: Fresh Air Issues

Sorry if I keep beating a dead horse, but how do I get this to be a 100% fresh air system?

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "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@xxxxxxxxxxxxxxx] On Behalf Of ntraughpee
> Sent: Tuesday, November 01, 2011 10:33 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> 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> , "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@xxxxxxxxxxxxxxx
> <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> 
> > 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> , 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> 
> > > 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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