Re: [EnergyPlus_Support] System volume for chilled and condenser water

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

There are example files which autocalculate loop volumes much smaller than 
10,000 gallons which show no stability problems.  For example, the reported 
loop volume for SolarCollectorFlatPlateWater.idf is 0.63787 m3 which is 168 
gallons.  The autocalculated loop volume is proportional to the loop maximum 
flow rate and the length of the zone time step.  If the loop maximum flow rate 
input is not autosized, be sure that it is not larger than it should be.  
Please send an example of an unstable simulation indicating what outputs 
(variable name and timestamp range) shows the instability.  You may upload the 
file to the yahoo group files area or send as a zipped e-mail attachment to 
energyplus-support@xxxxxxxx.

Mike


On 20 Apr 2007 at 17:57, maenebraska wrote:

> I have noticed that EnergyPlus becomes very unstable at system volumes 
> under 10,000 gallons.  
> 
> If I let the program autosize this value to something very large e.g. 
> 120,000 gal, what keeps the program from modeling such systems like a 
> thermal storage loop when the system volume is soo much larger than 
> the actual building and how can I improve program stability for 
> reasonable system volumes?
> 
> Thank you for your help,
> 
> Dan
> 
> 
> 
> 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 not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the
> Documentation link and press the "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 


========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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