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[EnergyPlus_Support] Re: How do you disable modulation of opening factors?
Thanks for explaining that!
It's a little strange that the decision of whether or not to open the
windows occurs on a minute by minute basis (this is how it appeared
when I output in detailed mode). It would be nice if there was a
control that could force the windows to be either open or closed for
at least a half an hour (or something other time chunk) to avoid the
unrealistic modelling of windows being opened and closed every minute
based on temperature conditions.
Also, I am trying to model cross ventilation, but the opposite windows
are not always opening at the same times. Is there any way to model
ventilation with temperature control and force the windows to open
simultaneously? I am guessing this has to be done with the constant
control mode and a schedule, but then the windows are opened
regardless of the outdoor air temperatures.
Thanks,
Kendra
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Kendra:
>
> What you have done is right to make all opening factors either 0 or 1.
> Output results are also right at "timestep" report frequency.
>
> There are two timesteps used in EnergyPlus: zone time step and
system time
> step. The zone time step is your input from the TIMESTEP IN HOUR
object. The
> system time step is used internally and is determined by zone
temperature
> difference between previous timestep and current timestep. If the
difference
> is more than 0.3C, the system time step is shorter than the zone
time step.
> The AirflowNetwork model is performed at the system timestep level.
If you
> use "detailed" reprt frequency, you can see opening factors are
either 0 or
> 1.0. When "timestep" reprot frequncey is used, the opening factors
are gived
> as an average value over a zone timestep when system time step <
zone time
> step. That is why you see opening factors vary between 0 and 1.0.
>
> Please let me know if you have more concerns.
>
> Lixing Gu
> Florida Solar Energy Center
>
> ----- Original Message -----
> From: "colotupper" <kendra.tupper@...>
> To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
> Sent: Wednesday, September 06, 2006 9:12 PM
> Subject: [EnergyPlus_Support] How do you disable modulation of opening
> factors?
>
>
> >I am simulating Natural Ventilation with Airflow Networks and my
> > Ventilation Control Mode = Temperature. I want to have only 2
> > conditions: closed windows (opening factor = 0) and open windows
> > (opening factor = 1). I have set Limit Value on Multiplier for
> > Modulating Venting Open Factor = 1, and all opening factors equal to 1
> > as well.
> >
> > For some reason, when i output hourly results, my Opening Factor and
> > Opening Factor Multiplier for Venting Modulation vary between 0
and 1.
> >
> > I read past messages about this problem and tried changing my
> > timesteps and reporting frequency, but this had no effect. Right now,
> > I have my timestep set to 1 and my report frequency set to timestep.
> > I also tried letting all of the fields default to disable the
> > modulation, but this had no impact either.
> >
> > I am going to post this file - if anyone has any suggestion, I would
> > greatly appreciate it!
> >
> > Thanks,
> >
> > Kendra
> >
> >
> >
> >
> >
> >
> > 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.idf
and press
> > the "search" button.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
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