RE: [EnergyPlus_Support] diffuse solar

[YuanLu Li <yli006@xxxxxxxxxxx>]

I think, these minor time shift and averaging appears with other variables as well.
 
For example, the outside dry bulb temperature listing at the output is unchanged at the hourly points when using timestep as listing interval (same as the EPW hourly value).  When listed as in a  hourly interval report, the value is the average of the preceding hour, which is slightly different from the original list value in the EPW.and is the same as the half hour points of the time step listing.
 
I have a feeling that this is done by the post processor using the ESO in time steps, and not at the simulation time.

 Dr. Li   
 

---

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: hujia06@xxxxxxxxx
Date: Sun, 31 Jan 2010 20:06:15 -0500
Subject: [EnergyPlus_Support] diffuse solar

 

Hi, all

 

In EnergyPlus, when timestep = 4, the diffuse solar in weather file is different from the output at the same hour. For example, in weather file, at 9:00, the diffuse solar is 58, while in the output, 58 appears at 8:30. This rule seems different from interpolation mentioned in help ref.

 

In calculating Daylight Factor, EP ref. mentions it uses hourly DF and then  interpolate the two hour DF to calculate the DF at time step in  one hour. So when calculating Daylight Factor, the Energyplus adopts which hour values of Diffuse and direct Radiation in the Outputfile?  Does EP use 58 (at 8:30 in the output), or use value at 8:00 in output (average values at 7:30 and 8:30, which are corresponding to 8: 00 and 9:00 in the weather file respectively) ? .

 

Thanks in advance,

 

jia

---

All your Hotmail contacts on your phone. Try it now.

__._,_.___

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.

Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe

__,_._,___