Re: [EnergyPlus_Support] Environment variables: Flow from FromZone to ToZone

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

1.  Report variables labeled "Environment" refer to the weather surrounding the 
building, either from the weather file or from a design day definition.  For 
subhourly timesteps, EnergyPlus interpolates hourly instantaneous values and 
the csv file reports average values over the hour, so the two will not match.  
If you want to see the weather file values in the csv file, report at the 
Timestep frequency, or set TIMESTEP IN HOUR = 1.

2.  The explanations of these output variables in the Input Output Reference, 
pp. 328-329 (pdf pp. 361-362) should help clear this up.  If not, ask more 
questions.

Mike


On 6 Jul 2005, at 22:10, ruby98103 wrote:

> Two issues:
> 
> 1. I can't find an explanation in the manual of the Environment 
> variable key value. I assume that it means the air outside of and 
> surrounding the building. For the variables that are in our weather 
> file, I would assume that it would just echo the weather file data.(I 
> am asking for an hourly average of the variable and am using two 
> simulation periods per hour.) That is not happening. 
> 
> We modified a weather file so wind direction and speed would be 
> stable for several hours to get a more steady state value for our 
> COMIS air flows. The temperature, radiation and other variables were 
> left the same as they are in the TMY2 file. But the Environmenta 
> variable is not reporting the same number, nor is it stable.
> 
> Details: for example, our weather file for 11 am to 1 pm is:
> time   dry b   dir   speed
> 1100   23.9   290   3.6
> 1200   25.0   290   3.6
> 1300   26.1   290   3.6
> 
> Our report gives the following:
> 1100   23.75  352.5 4.225
> 1200   24.725 357.5 4.925
> 1300   25.825 352.5 5.575
> 
> Just what is this Environment variable? Can I echo the weather file 
> to be sure it is being read correctly?
> 
> 2. For the reporting pair:
> "Air Flow from FromZone to ToZone through COMIS link" and
> "Air Flow from ToZone to FromZone through COMIS link"
> 
> which is the FromZone and which is the ToZone? Sometimes I have a 
> number for the hourly average that is about the same for both for a 
> given COMIS "Name of Associated EnergyPlus Surface" and sometimes it 
> is zero for one and real for the other.
> 
> How do I interpret this?
> 
> 
> 
> 
> 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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