Re: [TRNSYS-users] Type 34 : strange output

[David Bradley <bradley@tess-inc.com>]

Jeff,
  I ran into the same problem a few years ago. After much searching, I 
realized that Type34 assumes an isotropic sky for diffuse radiation. If you 
have your Type109 set to use an anisotropic sky model, you can actually get 
more radiation on a "shaded" surface that has a non projecting overhang or 
wingwalls. If you change Type109 parameter 3 to "1" the problem should go away.
Kind regards,
 David


At 10:39 4/7/2006, jfamailbox-i3er@yahoo.fr wrote:
> Dear Diego,
> Thanks for your answer, but it's not more clear for
> me, because I'put FSKY to 0.5 in my BUI, so results
> should be the same ?
> Regards,
> JeFF
> --- DIEGO A ARIAS <daarias@wisc.edu> a écrit :
>
> > Dear Jeff,
> >
> > The mathematical description of Type34 (Volume 5,
> > section 5.7.15)
> > explains that type 34 calculates the view factor for
> > the opening to the
> > sky.  The view factor for an unshaded vertical
> > surface is 0.5.  The
> > presence of wingwalls or overhang reduce the view
> > factor.
> > If you have an unshaded surface (overhang projection
> > equal to zero),
> > type 34 will use a shading factor equal to 0.5.
> > Please let me know if this answers your question or
> > if you have any
> > additional questions.
> > Best regards,
> >
> > Diego
> >
> > ----- Original Message -----
> > From: jfamailbox-i3er@yahoo.fr
> > Date: Friday, April 7, 2006 5:11 am
> > Subject: [TRNSYS-users] Type 34 : strange output
> > To: trnsys-users@engr.wisc.edu
> >
> > > Hello TRNSYS users,
> > > I've done simulations of simple room with a window
> > > south oriented and several overhang (type 34)
> > > settings.
> > > And I?ve different value without type 34(directly
> > > connected to type 109) and connected to type 34
> > with
> > > overhang projection set to zero !!!
> > > Someone could explain it ?
> > > I linked TPF file
> > >
> > > Regards,
> > > JeFF
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
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>
>
>
>
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