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[EnergyPlus_Support] Re: AFN How to Simulate Hung-Windows?

Dear Lixing,

if a hung-window is opened, the resulting effective opening area is one rectangular area and two triangles on the side - so i think for cross-ventilation (wind-driven) I might use the total area depending on the angle for the "effective area" model or, if the wind-pressure is strong enough not to generate any bidirectional flow, also the "detailed opening" model (Best may be to use a long vertical opening). May be the discharge coefficient has to be adopted. I am right?

The difficulty with the single sided bidirectional ventilation in combination with for example a bottom hung-window is that because of the resulting opening geometry (e.g. small triangular areas at the bottom and the bigger rectangular area at the top) the neutral pressure plane of that opening is more at the top and may be only 1/3 of the effective area is used for inflow (at the triangular areas).
So - to overcome this difficulty may be this neutral plane has to be shifted according to the geometry and opening angle. But may be there is some way around - like to use two openings which represent the hung-window. One for inflow - one for outflow. But this might be difficult to control. I thought may be you or somebody else in the support group has ideas how to model or read something about AFN and hung-windows...

Best,
Tobias




--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Tobias:
> 
> Glad to know you made it work using a small crack at the other side and
> verify results. I think you may use the detailed opening object to represent
> big windows, if you think the detailed opening model can meet your
> requirements. 
> 
> What is your definition of cross-ventilation?
> 
> Lixing
> 
> -----Original Message-----
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of tobiasschulzeoooitu
> Sent: Wednesday, October 05, 2011 11:54 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: AFN How to Simulate Hung-Windows?
> 
> Dear Lixing,
> 
> it does, if you chose a "detailed opening" for the bidirectional flow and as
> a second pseudo opening a very small crack on some other construction than
> the window (only to have two openings - which is necessary). I checked it
> against some simple analytical solutions and it worked out fine.
> 
> Any ideas for hung-windows and cross-ventilation?
> 
> Tobias
> 
> 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@> wrote:
> >
> > Tobias:
> > 
> > The AirflowNetwork model does not support single side ventilation. Please
> > let us know if you find a good network model to simulate two-way flows at
> a
> > single opening.
> > 
> > Hope this helps.
> > 
> > Lixing Gu
> > 
> > -----Original Message-----
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of
> tobiasschulzeoooitu
> > Sent: Wednesday, October 05, 2011 11:01 AM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: [EnergyPlus_Support] AFN How to Simulate Hung-Windows?
> > 
> > Hello,
> > 
> > I couldn't find how to describe Hung-Windows (top/bottom/side) in the AFN
> -
> > Model. May be the effective Area would be a way for cross ventilation, but
> > how to deal with bidirectional single sided ventilation? I plan to
> simulate
> > the ventilation rates according to an opening angle of hung windows.
> > Variables i could use (probably together with EMS) are the discharge
> > coefficient, the window hight, the window width and the opening factor. I
> > think for a controlled, bidirectional flow the detailed opening model
> should
> > be best. Do you have any recommendations how to model or some literature
> > describing the problem?
> > 
> > Thank you,
> > Tobias
> > 
> > 
> > 
> > 
> > 
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> 
> 
> 
> ------------------------------------
> 
> Primary EnergyPlus support is found at:
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> The primary EnergyPlus web site is found at:
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> Attachments are currently allowed but be mindful that not everyone has a
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