Re: [EnergyPlus_Support] COMIS Cp Calculations

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

>From the Input Output Reference for COMIS SIMULATION "Wind Pressure 
Coefficients" field, five different sets of Cp arrays are calculated, "for the 
four vertical facades and the roof . . . The calculated wind pressure 
coefficients are shown in the eplusout.cif file."

If entering Cp arrays by hand, there does not need to be 360 sets for each 
degree of angle, they will interpolate.

See example files 3zvent.idf and 3zventAutoCalcOfWindPressureCoeffs.idf

Mike




On 14 Jun 2005, at 0:35, ruby98103 wrote:

> The COMIS 3.0 manual gives you the distict impression that it 
> calculates a Cp value specific to a location (x,y,z) on a face (pg. 
> 101 "These routines calculate Cp at any position of a surface element 
> on the envelope of a block shaped building"). 
> 
> But the EnergyPlus manual gives the distinct impression (pg. 323 -
>  "will automatically calculate surface-averaged Cp values for the walls 
> and roof of the building") that it calculates only a single Cp value 
> averaged over the entire building. You can also put in a schedule of Cp 
> values for each facade, but there only one value is allowed for each 
> facade-wind direction pair, not one for each "Associated EnergyPlus 
> Surface" object-wind direction pair. 
> 
> Since most natural ventilation depends on there being a significant 
> difference between the Cp value of the windward windows and the leeward 
> windows, often enhanced by a difference in elevation, a value averaged 
> over the entire building seems usless to calculate natural ventilation 
> flows. Could someone please clarify this. 
> 
> Thank you.
> 
> 
> 
> 
> 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.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 



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




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