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[EnergyPlus_Support] Re: COMIS
Good morning,
Thank you Mike and Edward for your inputs.
I do have more than one crack (4) and no openings for the zone. I do
have a crack (air mass flow coef. of 0.000001) for an adjoining zone,
although it´s just for COMIS purposes (all zones have to be connected
to each other).
I thought about using the infiltration or the ventilation object, but
I still need COMIS for some openings. And in order to use any of
these objects I would have to use the Simple airflow model, instead
of COMIS (at least I think that the infiltration object will be
an "orfan" when using COMIS airflow model).
I think that some time ago I had some problems regarding cracks in
non-vertical surfaces (tilted roof). Is there any problem with COMIS
and tilted surfaces?
Thanks a lot, have a nice week,
Alexandre
PS - I'm going to a workshop in Lisbon where Drury Crawley will be
speaking. I wish him a nice stay in Portugal.
--- In EnergyPlus_Support@yahoogroupscom, "Edward G. Lyon"
<eglyon@s...> wrote:
> The network nature of COMIS should need at least 2 openings. I
would expect less flow than the equation may suggest. If you have 2
openings with the same coefficients, the flow would need to be split
between the two openings.
>
> It is far simpler to control a minimum ventilation with zone
infiltration instead of COMIS. Infiltration uses the same type of
wind pressure flow equation, but it does work to enter coefficients
that cancel the wind pressure component and establish a constant
ventilation flow by infiltration. It also requires only one object
per zone and not a network description like COMIS needs.
>
> ________________________________
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx on behalf of Michael J.
Witte
> Sent: Thu 6/9/2005 1:14 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: Re: [EnergyPlus_Support] COMIS
>
>
> I am not an expert on COMIS, but I would guess that this flow is
being reduced
> due to the restrictions of other flow openings? Perhaps you need
an equal and
> opposite crack to maintain the minimum flow at all times?
>
> Mike
>
>
> On 7 Jun 2005, at 8:30, alexandrevarela2000 wrote:
>
> > Dear all,
> >
> > While using COMIS I wanted to define a minimum flow rate for the
> > building. In order to achieve this I created a COMIS AIR
FLOW:Crack
> > object like this:
> >
> > Name: Vent
> > Air mass flow coefficient: 0.025
> > Air mass flow exponent: 0.0
> > Crack length: 1
> >
> > When looking at Infiltration-Air Change Rate report I was hoping
to get
> > a minimum ach related to 0.025. As I'm getting ach values below
what I
> > was expecting I don´t know what to make of it.
> >
> > Thank you for help,
> > Alexandre
> >
> > PS - Everybody thinking abou taking a vacation in Portugal, the
weather
> > is great!
> >
> >
> >
> >
> > 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.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
>
> ========================================================
> Michael J. Witte, GARD Analytics, Inc.
> EnergyPlus Testing and Support
> EnergyPlus-Support@g...
>
>
>
>
> The primary EnergyPlus web site is found at:
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