It should be "no re-cycle of zone air through a HVAC system" without special trement.
Lab air with special requirement is treated (filtered) before they are exhausted. The inlet air is also filtered. It is not really a HVAC comfort requirement. Energy usage is not an issue.
This is why I say that DOAS alone is not sufficient for the operating room of a hospital, and is not a requirement for providing fresh air to the building.
Many high rise building has a 100% DAOS equivalent because it takes air from the roof, blow it down every floor without defined volume control and exit through leaks in the building all the ways to the basement which is vented to outside. It does not have a return path, except as in my environment tank model.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: RRaustad@xxxxxxxxxxxx
Date: Tue, 1 Nov 2011 15:19:36 -0400
Subject: Re: [EnergyPlus_Support] Re: Fresh Air Issues
On 11/1/2011 2:29 PM, ntraughpee wrote:
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, "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
> > >
> >
>
-- Richard A. Raustad Senior Research Engineer Florida Solar Energy Center University of Central Florida 1679 Clearlake Road Cocoa, FL 32922-5703 Phone: (321) 638-1454 Fax: (321) 638-1439 or 1010 Visit our web site at: http://www.fsec.ucf.edu UCF - From Promise to Prominence: Celebrating 40 Years
__._,_.___
Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are currently allowed but be mindful that not everyone has a high speed connection. Limit attachments to small files.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___