RE: [EnergyPlus_Support] Time of runs

["Michael J. Witte" <mjwitte@xxxxxxxx>]

I would agree that memory may be the issue.  You can check this by monitoring 
memory usage in the Windows task manager.

I would add that warm up days should not be changed.  Each environment "warms 
up" the thermal history of the building by repeating the first day of the 
environment until the results change within the convergence tolerances 
specified in the BUILDING object.  The maximum number of warmup days is just an 
uppper limit.  The simulation reports the actual number of warmup days in the 
eio output file.

If the model has many detached shading surfaces (Surface:Shading:Detached:Fixed 
and Surface:Shading:Detached:Building), it may help to turn off the automatic 
mirroring of these shading surfaces:

  DIAGNOSTICS, DoNotMirrorDetachedShading;

This must be used with caution.  If DoNotMirrorDetachedShading is specified, 
then these surfaces must face toward the building being simulated, because 
surfaces only cast shadows in the direction they face.

In general, reducing the total number of surfaces helps speed up the 
simulation.  

Mike




On 4 Aug 2006 at 13:18, Edward G. Lyon wrote:

> I would say that you have a large model and that you need a fast machine with
> lots of memory to run it.  If you don't have enough memory, the computer
> spends most of its time swapping memory segments with the hard drive rather
> than calculating your program.
>  
> If you already have a super machine, I have no other suggestions.  I did find
> that changing the time steps with delighting calculations also affects the
> accuracy of the calculation, so that is a speed trade off.
> 
> ________________________________
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Clarice Bleil de
> Souza
> Sent: Friday, August 04, 2006 12:50
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Time of runs
> 
> 
> 
> Hi everybody,
> 
> I am running a simulation of a 3 storey building heavily glazed with 107
> zones. The simulation is taking too much time to run. I've tested the debug
> with 2 days only + the 2 design days and it took me around 10hs to run it. 
> 
> My settings are: 
> 1) minimal shading - but I'll need to change it to full
> 2) 25 warm up days - but I think I can reduce this one
> 3) 6 time steps in a hour
> 4) 14 periods of shading calculation - but I'd like to have less days if
> possible due to the heavily glazed facade
> 
> Can anybody give me a light about how can I reduce the calculation time so
> that I can run a whole year? My next try is going to be less time steps and
> less warm up days but full shading.
> 
> Thanks in advance for the help!
> 
> Best regards
> 
> Clarice
> 
> 
> 
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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