[EnergyPlus_Support] Re: Fresh Air Issues

["ntraughpee" <matthew.sverre.anderson@xxxxxxxxx>]

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, "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@xxxxxxxxxxxxxxx] On Behalf Of ntraughpee
> Sent: Monday, October 31, 2011 4:13 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> 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> , 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> 
> > From: matthew.sverre.anderson@
> > Date: Fri, 28 Oct 2011 20:49:18 +0000
> > Subject: [EnergyPlus_Support] Fresh Air Issues
> > 
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> > 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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