Re: [EnergyPlus_Support] Re: create EPW weather file

["Linda Lawrie linda@xxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx>]

Did you look further at the audit file from the weather
converter?

 Warning ** DirectNormalRadiation > max
theoretical        290 times
 Resultant values were set to a corrected value (max
theoretical).
 Warning ** PerezSplit DirectNormalRadiation > max
theoretical        281 times
 Resultant values were set to a corrected value (max
theoretical).

so, the direct normal was changed from a value to the max theoretical
value 290 times.

the relationship of global to direct and diffuse is:

Direct_Horizontal + Diffuse_Horizontal = Global Horizontal

Direct Normal is found by a relationship to the current (calculated) sun
altitude .

Hope that helps.
In the weather converter you can choose "not to fix data" -- I
don't remember if that removes the correction when it is greater than max
theoretical or not.

Yes, usually the solar radiation gained from weather stations is Global
Horizontal.

At 09:18 AM 6/2/2015, la.epfl@xxxxxxxxx [EnergyPlus_Support]
wrote:


> Hello everyone, 
>
> I was trying to make sense out of some file transformation I have made. I
> attach the CSV file, the def file I am using as well as the audit file of
> the conversion. 
>
> I would like to know if everything is fine in the process and clarify
> some topics. 
>
> The original data from the CSV file comes from a weather station
> measurment and I am automatically transcribing it in the CSV. I am mostly
> interested in having correct solar radiation interpolation. The station
> gives me a measurement for sun which I assume to be horizontal global
> radiation. Does that sound like a reasonable assumption or it might be
> something else ? I do not have so much information about the weather
> station it comes from wunderground.com data.
>
> Second, the audit file gives me warnings like:
> Warning ** DirectNormalRadiation   1076.0 > max
> theoretical=   690.6 Wh/mâ?¤ on date= 1/ 1 at hour=14
> Does that mean that my original data is not good and should I do
> something about it ?(I have checked latitude longitude, looks fine).
> Then when I look at the EPW file I have created, the direct normal
> radiation for this hour is not 1076 nor 690 but 829Wh/m2, which I don't
> really understand. 
>
> Finally, I was expecting the direct radiation to be greater than the
> horizontal global radiation, but that is not what happens in practice. Is
> that then false ?
>
> Any other advice concerning weather conversion and creating EPW based on
> measured data is welcome as well :)
>
> Thanks in advance,
>
> Best regards

__._,_.___

---

Posted by: Linda Lawrie <linda@xxxxxxxxxxxxxx>

---

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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.

Visit Your Group

• New Members 7

• Privacy • Unsubscribe • Terms of Use

__,_._,___