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RE: [EnergyPlus_Support] Re: HVAC Descriptions
The DB "unitary multizone" is indeed the same system type as Mike describes
i.e. a system where one zone is controlled and the other zones act as
sub-zones with no direct control. It sounds like we should rename it given
the meaning the term "multizone" has for North-American users.
Andy
-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]On Behalf Of Michael J. Witte
Sent: 24 April 2007 18:05
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: HVAC Descriptions
When you use COMPACT HVAC:ZONE:UNITARY and COMPACT HVAC:SYSTEM:UNITARY to
create a single HVAC system serving multiple zones, you are getting a system
where one zone is controlled and the other zones act as sub-zones with no
direct control. The terminal unit objects used in this case are DIRECT AIR.
This is not a "multizone" system in the traditional North-American sense of
the
word. In more detail, this system will serve multiple thermal zones with
each
zone receiving some fixed flow rate when the system is on. The system fan
and/or coils will cycle to meet the loads of the control zone, and the other
zone will get their fixed portion of the total system flow.
Because Andy said that the DB "unitary multizone" system requires setting
one
zone to be the control zone, I assume that it is using the same approach as
above and is not a "multizone" as you define it. So that system is also the
type that you are seeking to model.
To model a "multizone" system as you know the term in EnergyPlus, you would
use
the "Dual Duct:Const Volume" terminal unit which is not (yet) a COMPACT HVAC
option.
Mike
On 24 Apr 2007 at 14:55, msemech wrote:
> Some clarification is needed here.
>
> In HVAC Parlance, a "multizone" is a single central unit that
> provides individual control to several zones through several
> different individual duct systems.
>
> It does not behave like a single zone/constant volume system.
>
> Having said that, does DB or EnergyPlus mean something different by
> the use of the term "multizone"?
>
> Thanks, Gentlemen.
>
> Bruce J. Gustafson
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Andy Tindale" <andy@...>
> wrote:
> >
> > You can serve multiple zones in DesignBuilder with a single unitary
> system
> > by selecting an HVAC template using the 'Unitary multizone' compact
> HVAC
> > type. In this case, it is necessary to set one of the zones as
> being
> > thermostatic control zone.
> >
> > Andy
> >
> > -----Original Message-----
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]On Behalf Of Michael J.
> Witte
> > Sent: 23 April 2007 17:37
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: Re: [EnergyPlus_Support] HVAC Descriptions
> >
> >
> > I am not sure if there is a way within DesignBuilder to serve
> multiple zones
> > on
> > the same unitary system.
> >
> > One approach is to delete all of the DesignBuilder HVAC input
> objects, then
> > use
> > COMPACT HVAC:ZONE:UNITARY and COMPACT HVAC:SYSTEM:UNITARY to create
> a single
> > HVAC system serving multiple zones, designating one zone to be the
> control
> > zone.
> >
> > Mike
> >
> >
> > On 23 Apr 2007 at 15:04, msemech wrote:
> >
> > > Greetings:
> > >
> > > A basic question.
> > >
> > > I'm doing an energy analysis to ASHRAE 90.1. We've created the
> model
> > > using DesignBuilder (DB), but that doesn't do enough for us with
> HVAC
> > > system descriptions.
> > >
> > > We understand, in a basic fashion, how to read the IDF files. We
> need
> > > to model a building that has several different "zones" on a
> constant
> > > volume-single zone system. DB creates a separate system for each
> zone
> > > of control.
> > >
> > > Question: How is each zone "linked" to the HVAC system?
> > >
> > > Bruce J. Gustafson
> > >
> > >
> > >
> > > 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 not allowed -- please post any files to the
> appropriate
> > folder
> > > in the Files area of the Support Web Site.
> > >
> > > EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf
> under the
> > > Documentation link and press the "search" button.
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> >
> >
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support
> > EnergyPlus-Support@...
> >
> >
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 not allowed -- please post any files to the appropriate
folder in the Files area of the Support Web Site.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the
Documentation link and press the "search" button.
Yahoo! Groups Links
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http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
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