Re: [EnergyPlus_Support] Solar Transmission

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

My apologies for the very delayed response (I don't see that anyone has replied 
yet).

If I understand correctly, you are varying the TIMESTEP IN HOUR from 1 to 6?  
EnergyPlus standard weather data is hourly, and when TIMESTEP IN HOUR is 
greater than 1, the weather data is interpolated.  Solar data in weather files 
represents the total over the previous hour which is converted to an average 
rate for the hour and then applied as the rate on the half-hour.  These mid-
hour rates are then interpolated for the shorter time steps.  

That said, is there any complex shading going on here that might affect the 
results?  I would suggest turning on some additional report variables to
 understand what is changing between the two cases:

Zone,Average,Diffuse Solar [W/m2]
Zone,Average,Direct Solar [W/m2]
Zone,Average,Ground Reflected Solar [W/m2]
Zone,Average,Solar Azimuth Angle [degree]
Zone,Average,Solar Altitude Angle [degree]
Zone,Average,Solar Hour Angle [degree]
Zone,Average,Surface Ext Sunlit Area [m2]
Zone,Average,Surface Ext Sunlit Fraction []
Zone,Average,Surface Ext Solar Incident[W/m2]
Zone,Average,Surface Ext Solar Beam Incident[W/m2]
Zone,Average,Surface Ext Solar Sky Diffuse Incident[W/m2]
Zone,Average,Surface Ext Solar Ground Diffuse Incident[W/m2]
Zone,Average,Surface Ext Solar Beam Cosine Of Incidence Angle[]
Zone,Average,Surface Ext Solar From Sky Diffuse Refl From Ground[W/m2]
Zone,Average,Surface Ext Solar From Sky Diffuse Refl From Obstructions[W/m2]
Zone,Average,Surface Ext Beam Sol From Bm-To-Bm Refl From Obstructions[W/m2]
Zone,Average,Surface Ext Diff Sol From Bm-To-Diff Refl From Obstructions[W/m2]
Zone,Average,Surface Ext Solar From Bm-To-Diff Refl From Ground[W/m2]
Zone,Average,Window Transmitted Solar[W]
Zone,Average,Window Transmitted Beam Solar[W]
Zone,Average,Window Transmitted Diffuse Solar[W]

If there are shading devices, perhaps try commenting them out and make the same 
comparison.  Once you have isolated what is happening, if you still see a 
problem that you cannot explain, please upload your file to the yahoo files 
area in the Problem Submittals folder (zipped please).

Mike


On 5 Oct 2005, at 23:21, mrgn_ellis wrote:

> I'm trying to calculate the amount of solar radiation transmitted 
> through the windows on a facade, using the 'zone transmitted solar' 
> output variable, but i'm getting some funny numbers.
> when i report the variable hourly with one time step i the peak 
> radiation being around 75% higher than reporting the variable per time 
> step with 6 timesteps.
> 
> is this common, or is there a problem with using the highest and 
> lowest timestep values?
> 
> any help would be greatly appreciated.  thanks heaps for any help and 
> time.
> 
> 
> 
> 
> 
> 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.idf 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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