[TRNSYS-users] solar zenith angle

[David Bradley]

Charles,
  Both are based on the equations that are laid out in Duffie and 
Beckman's _Solar Engineering of Thermal Processes_. Type15 performs the 
computation in a subroutine called GetIncidentRadiation (look at lines 
3517 to 3539 of Type15.f90.) Type109 calculates it in a subroutine 
called suncalc (lines 2435 to 2437 of Type109.f90).  When we were 
developing Trnsys17, we did note a number of discrepancies about the way 
that Type109 was operating at timesteps other than 1 hour. You might run 
your comparison at a 1 hour time step and see if the problem goes away.
Best,
  David



On 7/15/2010 02:11, LAUNAY Charles 226591 wrote:
>
> Dear all,
>
> I would like to know how types 15 and 109 compute the solar zenith 
> angle. I can't find this information in the manual.
>
> I'm using TRNSYS 16.
>
> Thanks for your help.
>
> Charles LAUNAY
>
>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
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bradley at tess-inc.com

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