Re: [EnergyPlus_Support] How do you disable modulation of opening factors?

[Lixing Gu <gu@xxxxxxxxxxxx>]

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@xxxxxxxxx>
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
>
>
>
>
>
>
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>
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>
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>
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>
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>
>
>
>
> 




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