[EnergyPlus_Support] Re: AFN width & height factor / detailed opening

["tobiasschulzeoooitu" <tobias.schulze@xxxxxxxxxxxxxx>]

Dear Lixing,
thank you for the explanation - I understand now. May be it is worth to write this issue down in the I/O reference.



--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Tobias:
> 
> I checked the source code. The pressure variation due to height is
> calculated based on the window geometry, regardless of real opening area due
> to modulation. The real opening area is used to calculate flow rate in the
> component level, such as detailed opening component. The program is not
> advanced enough to make adjustment due to modulation. It is similar to solar
> entry through a window. It assumes windows are closed, regardless of real
> window position. The half open windows may generate its own shading for
> solar entry.
> 
> Therefore, it is the program limitation and assumption. Since the real
> opening areas and window geometry are the same in Cases 1, 2 and 3, the same
> results are expected.
> 
> Hope this helps.
> 
> Lixing
> 
>  
> 
> -----Original Message-----
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of tobiasschulzeoooitu
> Sent: Wednesday, June 08, 2011 7:31 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: AFN width & height factor / detailed
> opening
> 
> Dear Linxing,
> 
> the opening factor AFN:Surface is 1 as you told me to check. And the window
> geometry is also same - BUT the flow rates should be different because of
> the different opening geometry (as part of the window geo) due to the h&w
> factors. Lets say due to the h&w in factors in AFN:DetailedOpening I assumed
> that in 1) the opening is 0,1m wide and 1m high. And in 2) the opening is 1m
> wide and 0,1m high -> different opening geometry -> should result in
> different ACH.
> 
> 3) and 4) are geometrically modelled and 3) is close 1)&2) and 4) is much
> less (less height = less ACH = correct)
> BUT therefore I assume 2) to be wrongly calculated. Should be close to 4)
> 
> I compare the "AirflowNetwork Zone Infiltration Air Change Rate". No weather
> file necessary -> only DesignDay. In & Outdoor temp is fixed (20/24°C).
> You can see that from the idf file containing all 4 scenarios. I will send
> you per mail (I hope it works).
> 
> What do you think?
> 
> Regards
> 
> 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@> wrote:
> >
> > Tobias:
> > 
> > There are two issues. The first issue is window opening factor. If the
> > opening factor for Cases 1 and 2 are 1.0, both windows should get the same
> > flow rate due to the same geometry. Since the input files are not
> attached,
> > you may check the opening factor by yourself first.
> > 
> > The second issue is flow rate comparison. Since a two way flow is
> expected,
> > what flow rate do you compare, incoming flow, outgoing flow or a sum?
> > 
> > Please let me know what happens after check. You may also send your input
> > files and provide weather date file name if the weather file is available
> in
> > the web site. Then you need to specify which part of output file (rows and
> > columns) make you think a program code fault. 
> > 
> > Thanks.
> > 
> > Lixing 
> > 
> >    
> > 
> > -----Original Message-----
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of
> tobiasschulzeoooitu
> > Sent: Monday, June 06, 2011 12:09 PM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: [EnergyPlus_Support] AFN width & height factor / detailed opening
> > 
> > Hello,
> > 
> > after some parametric analysis I realized, that for a single sided
> > ventilation strategy, the volume flow is same for these two options:
> > 1) width factor = 0,1 & height factor = 1
> > 2) height factor = 0,1 & width factor = 1
> > 
> > One can assume, that the volume flow in case 1) is higher because of the
> > bidirectional opening model and higher density differences from top of the
> > opening to the bottom of the opening as the opening height is bigger.
> > 
> > Therefore I repeated the same cases, but changing the window geometry
> > according the previously mentioned factors (leaving the factors as 1).
> Here
> > the resulting volume flow for 
> > 3) opening width=0,1 & opening height=1
> > is much higher than with a 
> > 4) opening height=0,1 & opening width=1
> > 
> > This is as I assumed and flow for case 3)is very close to 1) & 2)
> > 
> > Concluding, there may be is a program code fault with the opening factors
> > when changing the height factor.
> > 
> > Unfortunately the analytic solution for the cases as it is described in
> the
> > engineering reference is very difficult to realize but I can send the 3
> idf
> > test files.
> > 
> > Best Regards,
> > Tobias
> > 
> > 
> > 
> > ------------------------------------
> > 
> > Primary EnergyPlus support is found at:
> > http://energyplus.helpserve.com or send a message to
> > energyplus-support@
> > 
> > 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 currently allowed but be mindful that not everyone has a
> > high speed connection.  Limit attachments to small files.
> > 
> > EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the
> > Documentation link and press the "search" button.
> > Yahoo! Groups Links
> >
> 
> 
> 
> 
> ------------------------------------
> 
> Primary EnergyPlus support is found at:
> http://energyplus.helpserve.com or send a message to
> energyplus-support@...
> 
> 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 currently allowed but be mindful that not everyone has a
> high speed connection.  Limit attachments to small files.
> 
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the
> Documentation link and press the "search" button.
> Yahoo! Groups Links
>




------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/