Re: [EnergyPlus_Support] Question: Simulation Time

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

Yes, the iteration errors are causing the long run time, especially in a 
buildin as large and complex as yours.  Maximum iteration errors are usually 
related to mass flow or temperature problems around the loop.  This occurs when 
the air loop side is doing something contrary to the zone equipment.  Examples 
of situations which may cause this include:  sum of peak terminal unit airflows 
does not equal the peak supply fan air flow, node connection errors, bad 
control nodes, incorrect use of active and passive branches, inconsistent 
equipment schedules, and inconsistent control setpoints.

Mike



On 6 May 2004, at 19:18, zhen tian wrote:

> Hi,All:
> 
> I have a question for the simulation time. I am simulating a big university
> building. I  just do two-days simulation and it takes hours to run and there
> will be warning "Warning ** SimHVAC: Maximum iterations exceeded for all HVAC
> loops, at CALGARY INT'L AB CAN WYEC2-B-25110 WMO#=718770, 01/02 09:45 - 09:52"
> and "Warning ** SimHVAC: Exceeding max iterations continues...250" . This
> warning continues until the end of the simualtion day. Is this problem causes
> such a long time simulation time? 
> 
> Could anybody tell me that which parameter causes this problem and how can I
> solve it?
> 
> Thanks.
> 
> David Tian
> 
> 
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> 
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx



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