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



This difference cannot be the result of interpolation - there is just 
way too much difference between the input and the output - where do  
you suggest that I look to try to determine what is going on?

For example, our weather file for 11 am to 1 pm:
time   wind dir   speed
1100    290        3.6
1200    290        3.6
1300    290        3.6
 
Our report gives the following for Environment variables:
time   wind dir   speed
1100    352.5     4.225
1200    357.5     4.925
1300    352.5     5.575
> > 

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
<mjwitte@g...> wrote:
> 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@g...




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