[EnergyPlus_Support] Re: Modulation of openings in Airflow Network

["omarvelling" <laxoayi@xxxxxxxxxxxxxxxx>]

Dear Lixing,

Thanks a lot for your prompt reply. Changing the reporting frequency from timestep to detailed has actually helped in better understanding the modulation process. At a Detailed reporting frequency, the window/door opening factor for each timestep is either 0 or 1 whereas when reporting at a Timestep frequency the values are averaged which explains the above zero values.

Omar


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Omar:
> 
> The zone temperatures used to check window or door openings are the values
> at the previous time step. You may use report frequency "Detailed" to see
> what happens. The zone temperatures at the current time step are calculated
> based on window openings, if the temperature difference between the zone
> temperature at the previous time step and Tset determines to open a window.
> 
> Hope this helps.
> 
> Lixing Gu
> 
>  
> 
>  
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of omarvelling
> Sent: Friday, April 15, 2011 4:16 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Modulation of openings in Airflow Network
> 
>  
> 
> 
> 
> 
> 
> 
> Hi all,
> 
> I'm trying to modulate, or to be precise, cancel the modulation of the
> opening size of an AirflowNetwork:Multizone:Surface object so that it can
> either be fully open (i.e. Multiplier equals 1.0) or closed i.e. (Multiplier
> equals 0.0) depending on the ventilation control mode. I have managed to
> achieve this when the ventilation control mode is set to 'Constant' by
> specifying a venting availabilty schedule. However, when using 'Temperature'
> as the ventilation control mode and by setting the Ventilation control zone
> temperature setpoint at 22 C I found that the output for the 'Window/Door
> opening factor' is greater than 0.0 even when the zone temperature is below
> 22 C, that is when Tzone < Tset indicating that the window is partially
> open. As shown below, I've tried to overcome this by setting the minimum
> venting opening factor field in the AirflowNetwork:Multizone:Zone object to
> 1.0. I've also set the two sets of Opening factor Data in the
> AirflowNetwork:Multi 
> 
> Can anyone tell me why this is happening?
> 
> Thanks in advance,
> 
> Omar
> 
>  
> 
> AirflowNetwork:SimulationControl,
>     Simulation Control,      !- Name
>     MultizoneWithoutDistribution,  !- AirflowNetwork Control
>     Input,                   !- Wind Pressure Coefficient Type
>     All Angles,              !- AirflowNetwork Wind Pressure Coefficient
> Array Name
>     ExternalNode,            !- Height Selection for Local Wind Speed
> Calculation
>     ,                        !- Building Type
>     500,                     !- 
> 
> AirflowNetwork:MultiZone:Zone,
>     1,                       !- Zone Name
>     Temperature,             !- Ventilation Control Mode
>     NV Setpoint Schedule,    !- Ventilation Control Zone Temperature
> Setpoint Schedule Name
>     1,                       !- Minimum Venting Open Factor {dimensionless}
>     0,                       !- Indoor and Outdoor Temperature Difference
> Lower Limit For Maximum Venting Open Factor {deltaC}
>     100,            & 
> 
> AirflowNetwork:MultiZone:Surface,
>     1-S WIN,                 !- Surface Name
>     Window 1,                !- Leakage Component Name
>     South Node,              !- External Node Name
>     1,                       !- Window/Door Opening Factor, or Crack Factor
> {dimensionless}
>     ZoneLevel,               !- Ventilation Control Mode
>     ,                        !- Ventilation Control Zone Tempe 
> 
> AirflowNetwork:MultiZone:Surface,
>     1-N WIN,                 !- Surface Name
>     Window 1,                !- Leakage Component Name
>     North Node,              !- External Node Name
>     1,                       !- Window/Door Opening Factor, or Crack Factor
> {dimensionless}
>     ZoneLevel,               !- Ventilation Control Mode
>     ,                        !- Ventilation Control Zone Tempe 
> 
> AirflowNetwork:MultiZone:Component:DetailedOpening,
>     Window 1,                !- Name
>     0.001,                   !- Air Mass Flow Coefficient When Opening is
> Closed {kg/s-m}
>     0.65,                    !- Air Mass Flow Exponent When Opening is
> Closed {dimensionless}
>     NonPivoted,              !- Type of Rectanguler Large Vertical Opening
> (LVO)
>     0,                       !- Extra Crack Length or Height of Pivoting
> Axis {m}
>     2,     &nbs
>




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